The two main ways in which disease and nutrition can influence fertility are by reducing fecundity or by extending the birth interval. Fecundity refers to reproductive ability, that is the potential to breed, as compared to fertility which denotes actual childbearing . Reduced fecundity, which is usually referred to as subfecundity, results from impairment of any of the biological aspects of reproduction, including coital inability, conceptive failure as well as pregnancy loss. Subfecundity is only one factor operating to reduce (...) fertility; other factors include those governing mate exposure and birth control. (shrink)

Fast and effective detection of the causative agent of malaria in humans, protozoan Plasmodium parasites, is of crucial importance for increasing the effectiveness of treatment and to control a devastating disease that affects millions of people living in endemic areas. The microscopic examination of Giemsa‐stained blood films still remains the gold‐standard in Plasmodium detection today. However, there is a high demand for alternative diagnostic methods that are simple, fast, highly sensitive, ideally do not rely on blood‐drawing and can (...) potentially be conducted by the patients themselves. Here, the history of Plasmodium detection is discussed, and advantages and disadvantages of diagnostic methods that are currently being applied are assessed. (shrink)

Securitization of infectious diseases may involve suspension of ordinary human rights and liberties. In the event of an epidemic, therefore, it is important to limit the occasions upon which draconian disease control measures are implemented in the name of security. The term ‘security’, moreover, should not be used too loosely if it is to retain force and meaning in political discourse. It may be argued that the bar for disease securitization should be set high so that it is (...) limited to contexts involving rapidly spreading pathogens. Such an approach, however, would rule out securitization of more slowly spreading, endemic diseases such as HIV/AIDS. An advantage of characterizing HIV/AIDS as a security threat in developing countries, where the burden of the disease is concentrated, is that this is likely to mobilize resources needed to improve the situation there. That is, if HIV/AIDS is convincingly framed as a security threat, then governments may recognize self‐interested reasons to ramp up control measures. Following consideration of arguments for narrow (excluding HIV/AIDS) versus broad (including HIV/AIDS) conceptions of security, we conclude that the legitimacy of ‘securitizing’ HIV/AIDS ultimately turns on empirical and semantic issues, and we emphasize the importance of distinguishing (1) the nature of the threat posed by HIV/AIDS and (2) the measures required to address that threat. (shrink)

With a large number of forcibly displaced people seeking safety, the EU is facing a challenge in maintaining solidarity. Europe has seen millions of asylum seekers crossing European borders, the largest number of asylum seekers since the second world war. Endemic diseases and often failing health systems in their countries of origin, and arduous conditions during transit, raise questions around how to meet the health needs of this vulnerable population on arrival in terms of screening, vaccination, and access to (...) timely and appropriate statutory health services. This paper explores the potential role of the principle of reciprocity, defined as the disposition ‘to return good in proportion to the good we receive, and to make reparations for the harm we have done’, as a mid-level principle in infectious disease screening policies. More than half of the European countries implemented screening programmes for newly arrived asylum seekers. Screening may serve to avoid potential infectious disease risks in the receiving countries as well as help identify health needs of asylum seekers. But screening may infringe upon basic rights of those screened, thus creating an ethical dilemma. The use of the principle of reciprocity can contribute to the identification of potential improvements for current screening programmes and emphasizes the importance of certain rights into guidelines for screening. It may create a two way moral obligation, upon asylum seekers to actively participate in the programme, and upon authorities to reciprocate the asylum seekers’ participation and the benefits for the control of public health. The authors argue that the reciprocity principle leads to a stronger ethical justification of screening programmes and help achieve a balance between justifiable rights claims of the host population and the asylum seekers. The principle deserves a further and more thorough exploration of its potential use in the field of screening, migration and infectious diseases. (shrink)

Controlled human infection challenge studies (CHIs) involve intentionally exposing research participants to, and/or thereby infecting them with, micro‐organisms. There have been increased calls for more CHIs to be conducted in low‐ and middle‐income countries (LMICs) where many relevant diseases are endemic. This article is based on a research project that identified and analyzed ethical and regulatory issues related to endemic LMIC CHIs via (a) a review of relevant literature and (b) qualitative interviews involving 45 scientists and ethicists with (...) relevant expertise. In this article we argue that though there is an especially strong case for conducting CHIs in endemic (LMIC) settings, certain ethical issues related to the design and conduct of such studies (in such settings) nonetheless warrant particularly careful attention. We focus on ethical implications of endemic LMIC CHIs regarding (a) potential direct benefits for participants, (b) risks to participants, (c) third‐party risks, (d) informed consent, (e) payment of participants, and (f) community engagement. We conclude that there is a strong ethical rationale to conduct (well‐designed) CHIs in endemic LMICs, that certain ethical issues warrant particularly careful consideration, and that ethical analyses of endemic LMIC CHIs can inform current debates in research ethics more broadly. (shrink)

BackgroundIn the context of limited health care budgets in countries where Neglected Tropical Diseases (NTDs) are endemic, scaling up disease control interventions entails the setting of priorities. However, solutions based solely on cost‐effectiveness analyses may lead to biased and insufficiently justified priorities.ObjectivesThe objectives of this paper are to 1) demonstrate how a range of equity concerns can be used to identify feasible priority setting criteria, 2) show how these criteria can be fed into a multi‐criteria decision‐making matrix, and (...) 3) discuss the conditions under which this decision‐making procedure should be carried out in a real‐world decision‐making context.MethodsThis paper draws on elements from theories of decision analysis and ethical theories of fair resource allocation. We explore six typical NTD interventions by employing a modified multi‐criteria decision analysis model with predefined criteria, drawn from a priority setting guide under development by the WHO. To identify relevant evidence for the six chosen interventions, we searched the PubMed and Cochrane databases.DiscussionOur in vitro multi‐criteria decision analysis suggested that case management for visceral leishmaniasis should be given a higher priority than mass campaigns to prevent soil‐transmitted helminthic infections. This seems to contradict current health care priorities and recommendations in the literature. We also consider procedural conditions that should be met in a contextualised decision‐making process and we stress the limitations of this study exercise.ConclusionBy exploring how several criteria relevant to the multi‐facetted characteristics of NTDs can be taken into account simultaneously, we are able to suggest how improved priority settings among NTDs can be realised. (shrink)

Human infection challenge studies (HCS) involve intentionally infecting research participants with pathogens (or other micro-organisms). There have been recent calls for more HCS to be conducted in low-income and middle-income countries (LMICs), where many relevant diseases are endemic. HCS in general, and HCS in LMICs in particular, raise numerous ethical issues. This paper summarises the findings of a project that explored ethical and regulatory issues related to LMIC HCS via (i) a review of relevant literature and (ii) 45 qualitative (...) interviews with scientists and ethicists. Among other areas of consensus, we found that there was widespread agreement that LMIC HCS can be ethically acceptable, provided that they have a sound scientific rationale, are accepted by local communities and meet usual research ethics requirements. Unresolved issues include those related to (i) acceptable approaches to trade-offs between the scientific aim to produce generalisable results and the protection of participants, (iii) the sharing of benefits with LMIC populations, (iii) the acceptable limits to risks and burdens for participants, (iv) the potential for third-party risk and whether the degree of acceptable third-party risk is different in endemic settings, (v) the conditions under which (if any) it would be appropriate to recruit children for disease-causing HCS, (v) appropriate levels of payment to participants and (vi) appropriate governance of (LMIC) HCS. This paper provides preliminary analyses of these ethical considerations in order to (i) inform scientists and policymakers involved in the planning, conduct and/or governance of LMIC HCS and (ii) highlight areas warranting future research. Insofar as this article focuses on HCS in (endemic) settings where diseases are present and/or widespread, much of the analysis provided is relevant to HCS (in HICs or LMICs) involving pandemic diseases including COVID19. (shrink)

Pre-existing medical conditions and co-infections are common to all human populations, although the natures of the pre-existing conditions and the types of co-infections vary. For these reasons, among others, the arrival of a highly infectious pathogenic agent may differentially affect the disease burden in different sub-populations, as a function of varying combinations of endemic disease, chronic disease, genetic or epigenetic vulnerabilities, compromised immunological status, and socially determined risk exposure. The disease burden may also vary considerably (...) by age cohort and socio-economic status. The social consequences of infection, the medical sequelae, and the paths of recovery from infection may also vary, according to these variables. As a result, different sub-populations may have different experiences of a disease process, including when and how an epidemic comes to an end. This essay suggests that historians' engagement with path-breaking biological and medical anthropological research will allow new approaches to understanding disease processes that will enrich the study of epidemics and their endings. It is organized in three sections. The first discusses some general approaches to and assumptions about epidemics that are used by many historians. The second introduces new perspectives on the study of historical epidemics opened up by the medical anthropological concept of syndemic disease interactions and by an engagement with biological scientific perspectives. It briefly discusses two rural epidemics-one of anemia caused by the syndemic interaction of hookworm and malaria co-infections in early 20th-century British Malaya, and the other of rebound infections caused by the loss of acquired immunity to falciparum malaria in mid-20th-century Liberia-that illustrate, respectively, the utility of the concept of syndemic disease interactions and the centrality of immunological status in understanding epidemic outbreaks in these discrete populations. The third section addresses some of the research considerations involved in moving beyond the single pathogen model of epidemic disease. (shrink)

Background: Dengue Disease is a mosquito-borne tropical disease caused by the dengue virus, symptoms typically begin three to fourteen days after infection. This may include a high fever, headache, vomiting, muscle and joint pains, and a characteristic skin rash. Dengue serology is applied in different settings, such as for surveillance, in health care facilities in endemic areas and in travel clinics in non-endemic areas. The applicability and quality of serological tests in dengue endemic regions has (...) to be judged against a background of potential cross reactivity with other flavi-viruses, difficulties in distinguishing primary from secondary infections and technological problems related to the fact that most dengue endemic regions are relatively poor of resources .Objectives: to help doctors and patients in diagnosing Dengue Disease and give them the information of how to prevent Dengue Disease and to be able to understand the signs and symptoms of Dengue Disease. Methods: We collected all relevant material for Dengue Disease. Then we designed and implemented a knowledge based system for diagnosing Dengue Disease using SL5 Object Language. Results: The knowledge based system was evaluated by a group of Patients and specialized doctors and they found it very friendly and easy to use. (shrink)

Background In the context of limited health care budgets in countries where Neglected Tropical Diseases are endemic, scaling up disease control interventions entails the setting of priorities. However, solutions based solely on cost-effectiveness analyses may lead to biased and insufficiently justified priorities. Objectives The objectives of this paper are to 1) demonstrate how a range of equity concerns can be used to identify feasible priority setting criteria, 2) show how these criteria can be fed into a multi-criteria decision-making (...) matrix, and 3) discuss the conditions under which this decision-making procedure should be carried out in a real-world decision-making context. Methods This paper draws on elements from theories of decision analysis and ethical theories of fair resource allocation. We explore six typical NTD interventions by employing a modified multi-criteria decision analysis model with predefined criteria, drawn from a priority setting guide under development by the WHO. To identify relevant evidence for the six chosen interventions, we searched the PubMed and Cochrane databases. Discussion Our in vitro multi-criteria decision analysis suggested that case management for visceral leishmaniasis should be given a higher priority than mass campaigns to prevent soil-transmitted helminthic infections. This seems to contradict current health care priorities and recommendations in the literature. We also consider procedural conditions that should be met in a contextualised decision-making process and we stress the limitations of this study exercise. Conclusion By exploring how several criteria relevant to the multi-facetted characteristics of NTDs can be taken into account simultaneously, we are able to suggest how improved priority settings among NTDs can be realised. (shrink)

Modelling contagious diseases needs to include a mechanistic knowledge about contacts between hosts and pathogens as specific as possible, e.g., by incorporating in the model information about social networks through which the disease spreads. The unknown part concerning the contact mechanism can be modelled using a stochastic approach. For that purpose, we revisit SIR models by introducing first a microscopic stochastic version of the contacts between individuals of different populations (namely Susceptible, Infective and Recovering), then by adding a random (...) perturbation in the vicinity of the endemic fixed point of the SIR model and eventually by introducing the definition of various types of random social networks. We propose as example of application to contagious diseases the HIV, and we show that a micro-simulation of individual based modelling (IBM) type can reproduce the current stable incidence of the HIV epidemic in a population of HIV-positive men having sex with men (MSM). (shrink)

Common monogenic genetic diseases, ones that have unexpectedly high frequencies in certain populations, have attracted a great number of conflicting evolutionary explanations. This paper will attempt to explain the mystery of why two particularly extensively studied common genetic diseases, Tay Sachs disease and cystic fibrosis, remain evolutionary mysteries despite decades of research. I review the most commonly cited evolutionary processes used to explain common genetic diseases: reproductive compensation, random genetic drift (in the context of founder effect), and especially heterozygote (...) advantage. The latter process has drawn a particularly large amount of attention, having so successfully explained the elevated frequency of sickle cell anemia in malaria-endemic areas. However, the empirical evidence for heterozygote advantage in other common genetic diseases is quite weak. I introduce and illustrate the significance of a hierarchy of genetic disease phenomena found within the genetic disease explanations, which include the phenomena: single mutation variants of a common genetic disease, single genetic diseases, and classes of diseases with related phenotypic effects. I demonstrate that some of the confusion over the explanations of common genetic diseases can be traced back to confusions over which phenomena are being explained. I proceed to briefly evaluate the existing evidence for two common human genetic diseases: Tay Sachs disease and cystic fibrosis. The above considerations will ultimately shed light on why these diseases’ evolutionary explanations remain so deeply unresolved after so such a great volume of research. (shrink)

The globalization in business and tourism becomes crucial more and more for the economical sustainability of local communities. In the presence of an epidemic outbreak, there must be such a decision on the policy by the host community as whether to accept visitors or not, the number of acceptable visitors, or the condition for acceptable visitors. Making use of an SIRI type of mathematical model, we consider the influence of visitors on the spread of a reinfectious disease in a (...) community, especially assuming that a certain proportion of accepted visitors are immune. The reinfectivity of disease here means that the immunity gained by either vaccination or recovery is imperfect. With the mathematical results obtained by our analysis on the model for such an epidemic dynamics of resident and visitor populations, we find that the acceptance of visitors could have a significant influence on the disease’s endemicity in the community, either suppressive or supportive. (shrink)

This paper attempts to show how leading contemporary disciplines influenced the discovery of Chagas' disease and the formation of the early disease concept. Chagas was among the first generation of Brazilian trained scientists who incorporated modern principles of tropical medicine in its research. Thus, Chagas was familiar with characteristics of vector borne tropical diseases such as malaria and yellow fever. The detection of a hitherto unknown trypanosome in the gut of a reduviid bug prompted him to search for (...) a related vector borne disease. Among the disciplines that were influential on Chagas' discovery and early disease description were pathology, entomology and parasitology. Parasitology as a new discipline was of crucial importance to tropical medicine and had a political dimension in the context of colonial medicine. Hence, leading scientists in tropical medicine were located in European countries and in the United States of America. One of these was the German Schaudinn School of Protozoology. The early description of American Trypanosomiasis can also be seen as a reflection of the Schaudinn School of Protozoology which dominated Chagas' scientific orientation towards parasitology with regard to the interpretation of the observed phenomena of the life cycle and the morphology and biology of T. cruzi. The first Chagas' disease concept was based on research of the biology and entomology of the trypanosome and its vector as well as on pathological studies of fatal cases. This concept was characterized by a confusion of some of the chronic forms of the disease, as iodine deficiency and goitre were endemic in some rural regions in Brazil. Therefore, early concepts of the disease faced strong opposition and even raised doubts about its existence. (shrink)

International health research in malaria-endemic settings may include screening for sickle cell disease, given the relationship between this important genetic condition and resistance to malaria, generating questions about whether and how findings should be disclosed. The literature on disclosing genetic findings in the context of research highlights the role of community consultation in understanding and balancing ethically important issues from participants’ perspectives, including social forms of benefit and harm, and the influence of access to care. To inform research (...) practice locally, and contribute to policy more widely, this study aimed to explore the views of local residents in Kilifi County in coastal Kenya on how researchers should manage study-generated information on sickle cell disease and carrier status. (shrink)

Until the recent spread of public-private partnerships, pharmaceutical firms had avoided research and development into neglected tropical diseases (NTDs). Because these are diseases that affect the poorest populations in developing regions, research and development initiatives have for the most part depended on the resources and expertise drawn from academia, international organizations, and intermittent state interventions in disease-endemic countries. Over the last few decades, however, public-private product development partnerships (PDPs) have been introducing new collaborative agreements in which the existing (...) resources and expertise combine with the those traditionally withheld by the pharmaceutical industry and global health NGOs. This paper explores recent transformations in the representation of NTDs by examining the shifting logic and spaces of knowledge production which the advent of PDPs has enabled. An analysis of two case studies focused on Chagas disease-related initiatives addresses recurring preoccupations in Science, Technology and Society studies as well as in critical analyses of PDPs: that is, the back-and-forth movement of the disease from being an object of scientific inquiry to a public health concern, and the legitimacy risks and material asymmetries entailed in global health PDPs. Both cases show that it is major global health stakeholders and experts in non-endemic countries, rather than transnational pharmaceutical firms, that exert the greatest influence upon these changing representations: PDPs attempt to expand the preexisting biomedical focus on NTDs by means of incorporating “real world” drug development preoccupations (which I term epistemic shifts), but they also combine their stated global humanitarian aim with security concerns about the diseases spreading to non-endemic, industrialized countries (which I term geographical shifts). (shrink)

Donald Kuspit's The Cult of the Avant‐Garde Artist traces the therapeutic mission of modern art through its rise and decline into postmodern decadence. The problems Kuspit rightly finds in such artists as Warhol and Koons, however, are endemic to modernism itself: its diagnosis of bourgeois society as sick and in need of cure is fundamentally unsound. The modernist cure is, moreover, worse than the purported disease. What modernists call kitsch is, in many cases, a healthy, tragic view of (...) life. And while modernist metaphysics teaches the need for unmediated sensory experience and the inauthenticity of reproduction and representation, contemporary science shows these ideas to be without foundation. (shrink)

As COVID-19 drags on and new vaccines promise widespread immunity, the world's attention has turned to predicting how the present pandemic will end. How do societies know when an epidemic is over and normal life can resume? What criteria and markers indicate such an end? Who has the insight, authority, and credibility to decipher these signs? Detailed research on past epidemics has demonstrated that they do not end suddenly; indeed, only rarely do the diseases in question actually end. This article (...) examines the ways in which scholars have identified and described the end stages of previous epidemics, pointing out that significantly less attention has been paid to these periods than to origins and climaxes. Analysis of the ends of epidemics illustrates that epidemics are as much social, political, and economic events as they are biological; the “end,” therefore, is as much a process of social and political negotiation as it is biomedical. Equally important, epidemics end at different times for different groups, both within one society and across regions. Multidisciplinary research into how epidemics end reveals how the end of an epidemic shifts according to perspective, whether temporal, geographic, or methodological. A multidisciplinary analysis of how epidemics end suggests that epidemics should therefore be framed not as linear narratives—from outbreak to intervention to termination—but within cycles of disease and with a multiplicity of endings. (shrink)

Nigeria is developing country where the practice of euthanasia is not legalized. But a look at the socio-economic conditions of Nigeria calls for the need to legalize the practice in this country. This paper examines the features of this country such as poverty, endemic diseases and a low level of investment in healthcare systems . It argues for the need to legalize euthanasia by justifying it as a policy and practice and identifying factors which are to be taken into (...) account. They include poor standard of living which reduces the life span of many and limited health care resources which prevents access to health care. The paper justifies legalizing euthanasia in Nigeria by responding to some arguments against euthanasia raised by critics emphasizing at the same time ethical issues such as autonomy, dignity and quality of life for euthanasia debate. It concludes by stressing that in Nigeria, a competent person who is terminally ill and undergoing severe pain should be able to determine how and when to end his life; the possibility of this will only depend on the legalization of euthanasia in this country. (shrink)

Next SectionAccess to medicines, vaccination and care in resource-poor settings is threatened by the emigration of physicians and other health workers. In entire regions of the developing world, low physician density exacerbates child and maternal mortality and hinders treatment of HIV/AIDS. This article invites philosophers to help identify ethical and effective responses to medical brain drain. It reviews existing proposals and their limitations. It makes a case that, in resource-poor countries, ’locally relevant medical training’—teaching primarily locally endemic diseases and (...) practice in scarcity conditions, training in rural communities and admitting rural students preferentially—could help improve retention. Locally relevant training would arguably diminish medical brain drain in five ways. It would (i) make graduates less attractive for Western employers, (ii) align graduates’ expectations with actual practice, diminishing ‘burn-out’, (iii) enhance the professional prestige of local practice, (iv) hold rotations in, and recruit applicants from, rural areas, which is known to improve retention there, and (v) create local career development options that attract practitioners to stay. Such educational reform may raise worries about poor-quality care, breach of the freedom of education and occupation, breach of the freedom of movement, unequal distribution of opportunities among students, hypocrisy and resistance from influential actors. We address these worries. (shrink)

The circumstances that create the need for humanitarian action are rarely morally neutral. The extremes of deprivation and want that demand a humanitarian response are often themselves directly caused by acts of war, persecution or misgovernment. And even when the direct causes lie elsewhere—when suffering and loss are caused by natural disaster, endemic disease or poverty of natural resources—the explanations of why some people are afflicted, and not others, are not morally neutral. It is those without economic or (...) political power who starve in famines, those who inhabit the most marginal areas who are killed by floods and landslides, those without access to basic education and health care who die from easily preventable diseases. The societies in which these things can happen are unjust, and the injustice of disempowerment is both itself one of the universal afflictions of poverty and a condition of its many other vulnerabilities. (shrink)

Italian medical history in the age of positivism showed a strong interest in epidemics. This can be seen in Alfonso Corradi’s monumental Annali (1865-1895) and in works of other 19th-century historians who addressed major public health issues in the newly unified country. Local history was also widely practiced in Italy, and it was instrumental in discovering and publishing a wealth of documentation on past epidemic and endemic diseases, as well as on measures such as quarantines that were invented or (...) introduced in the peninsula as early as the late Middle Ages. The way Italian historians looked at epidemics in the 20th century was shaped by politics, religion and literature more than by demography, epidemiology, or technical knowledge in the medical field. This article and its accompanying bibliography will focus on regional historiography and deal with the history of plague, smallpox, cholera and malaria, and other diseases addressed in works published after the 1980s. (shrink)

The rapid changes that syphilis underwent after the first major outbreak that occurred in Naples in the mid-1490s are believed to constitute the first well-documented example of a human disease. The new plague was of exceptional virulence, highly contagious and causing severe ulceration at the site of infection. According to medical and other historical sources, the ‘genius epidemics’ changed some years after this onset, and a slower-progressing form of syphilis seems to have replaced the initial severe form, as do (...) many virulent epidemic infectious diseases that appear in devastating forms in a previously uninfected population. But what exactly were the features of the disease at the moment of its appearance in Europe at the end of the fifteenth century? How many years did it take for the early, virulent form to be replaced and become endemic? What was the pace of these changes through the decades following the onset of the epidemic? In this essay, I review these issues through an analysis of a large number of chronologically-ordered primary historical sources. (shrink)

CRISPR‐Cas technology accelerates development of fast, accurate, and portable diagnostic tools, typified by recent applications in COVID‐19 diagnosis. Parasitic helminths cause devastating diseases afflicting 1.5 billion people globally, representing a significant public health and economic burden, especially in developing countries. Currently available diagnostic tests for worm infection are neither sufficiently sensitive nor field‐friendly for use in low‐endemic or resource‐poor settings, leading to underestimation of true prevalence rates. Mass drug administration programs are unsustainable long‐term, and diagnostic tools – required to (...) be rapid, specific, sensitive, cost‐effective, and user‐friendly without specialized equipment and expertise – are urgently needed for rapid mapping of helminthic diseases and monitoring control programs. We describe the key features of the CRISPR‐Cas12/13 system and emphasise its potential for the development of effective tools for the diagnosis of parasitic and other neglected tropical diseases (NTDs), a key recommendation of the NTDs 2021–2030 roadmap released by the World Health Organization. (shrink)

Addiction: A Philosophical Approach CHAPTER ABSTRACTS “Introduction: Dismantling the Catchphrase” by Candice Shelby Shelby dismantles the catchphrase “disease of addiction.” The characterization of addiction as a disease permeates both research and treatment, but that understanding fails to get at the complexity involved in human addiction. Shelby introduces another way of thinking about addiction, one that implies that is properly understood neither as a disease nor merely as a choice, or set of choices. Addiction is a phenomenon emergent (...) from a complex dynamic system that is at once physical, psychological, social, and more. “A Philosophical Analysis of Addiction” by Candice Shelby Shelby brings much-needed clarity to the discourse surrounding the topic of addiction. Arguing that addiction can neither properly be understood as a disease nor as merely a set of choices, Shelby exposes the weaknesses of both approaches. She shows that addicted persons do not exhibit the elements characteristic of compulsion, nor does an account of addiction in terms of weakness of will, or irrational choosing, provide a satisfying explanation. Instead, by replacing traditional substance ontology with process ontology, and accepting the reality of emergent entities, a coherent account of persons, minds, and addiction can be provided. A fundamental philosophical shift is necessary to see that bodies, minds, values, and addictions are all part of the natural world. “Addiction at the Individual Level” by Candice Shelby Shelby discusses the most influential accounts of addiction as it is understood at the purely individual level. From hedonic theories to incentive sensitization, to habit theories of addiction, to behavioral theories and the ego depletion theory, Shelby considers a variety of approaches to understanding addiction in individuals, as framed in both psychological and in neuroscientific terms. She notes some important caveats that should be considered before accepting the research regarding addiction at the individual level, namely that the scanning studies that are so popularly used to characterize addiction in neurobiological terms are ambiguous, and rely on numerous assumptions that may be false, and that certainly mislead. Shelby provides much-needed critique of both disease and choices models as they characterize addiction at the individual level. “Addiction and the Local Environment” by Candice Shelby Shelby argues that human addiction cannot be understood without serious consideration of the individual’s local environment, her home and family. From the gestational environment to interactions with caregivers during post-natal development to the adult environment in which people become addicted, Shelby shows that no one becomes an addict in a vacuum. Stress is a major influence in the environment throughout life, and has serious consequences for addictive vulnerability. Genetic influences as well are important to addictive vulnerability, but genes always express in interaction with their environment. Social acceptance or rejection is another particularly important factor in the local environment with respect to both coming to be addicted and transitioning out of it. “The Relation Between Addiction and Culture” by Candice Shelby Shelby provides a groundbreaking analysis of the relation between addicts and the cultures that breed them. In this cultural critique, Shelby shows that addictions to certain substances have historically been both the solution to the problem of how to grow economies and control people, and a problem for economic productivity and controlling citizens. Not all cultures have even the concept of addiction, while others, such as the contemporary Western world, and the U.S. in particular, seem to foster it. Shelby shows that addiction is both a cultural construct and, from another way of thinking about it, the result of conditions created by particular cultures. Social inequities, alienation, driving capitalism, and in particular the power of pharmaceutical companies, all contribute to the spiraling endemic of addiction. “Addiction and Meaning” by Candice Shelby Shelby provides a unique argument that understanding how meanings work is essential to a complete analysis of addiction. Individuals experiencing addiction and those who care about and for them often utterly fail to communicate. This is because their respective systems of meanings come to be significantly different. Meanings are not, Shelby argues, best understood in the symbolic terms that characterized the theory of language in the 20th century, but are better apprehended as emotion-rich prototypes carved from repeated interaction with the world. Becoming addicted essentially changes one’s entire system of meanings. Requisite to transitioning out of addiction is a Gestalt-type shift in one’s system of meanings. This holistic way of understanding meanings also provides one level of explanation of what happens when an addict relapses. “The Phenomenology of Addiction and its Implications” by Candice Shelby One way of judging theories of addiction is by how well they capture the phenomenal descriptions that addicts give of their own experiences. Shelby considers variations on 5 basic patterns of addictive experience through the eyes of particular individuals who lived through addictive periods, and shows how even the most influential theories of addiction fail to capture all of them. She argues that an important implication of taking the details of individuals’ addictive stories seriously is that addiction must be understood as a personal phenomenon emergent from a particular complex dynamic system. As her theory of addiction would lead one to expect, no two addicts are the same, and no single-focus theory can explain why not. “Possibilities for Transitioning Out of Addiction” by Candice Shelby Shelby provides numerous strategies for transitioning out of addiction. Given that the vast majority of addiction treatment programs currently available are 12-step based and only successful about 5-8% of the time, it is essential that other approaches be undertaken. Shelby canvasses a variety of options for helping addicted individuals to make the transition out of their troubled pattern of thinking and behaving. From direct brain interventions to drugs to trauma therapy to exercise and nutrition to habit reformation to use of narrative and changing one’s social context as ways of redefining the self, Shelby shows that the possibilities for transitioning out of addiction are legion. Perhaps the best approach is to understand addiction treatment in terms of providing physical, psychological, and social tool kits. “Addiction Emerges from a Complex Dynamic System” by Candice Shelby Shelby considers whether there truly exists such a thing as “an addict” or “addictive thinking” in the universal sense. She concludes that within the context of disruptive substance use or repetitive engagement in certain activities, ordinary human cognitive biases and behavior patterns are categorized as addictive. Addiction, she argues, is best understood as an irreducible human reality, emergent from a sufficiently complex dynamic system (an organism with self-awareness, within a particular cultural milieu) that is both shaped by and contributes to the shaping of its environment. Attempts to simplify addiction into one or a few dimensions may create a solvable problem, but by doing so they fail to solve the real one. (shrink)

In controlled human infection (CHI) studies, investigators deliberately infect healthy individuals with pathogens in order to study mechanisms of disease or obtain preliminary efficacy data on investigational vaccines and medicines. CHI studies offer a fast and cost‐effective way of generating new scientific insights, prioritizing investigational products for clinical testing, and reducing the risk that large numbers of people are exposed to ineffective or harmful substances in research or in practice. Yet depending on the pathogen, CHI studies can involve significant (...) risks or burdens for participants, pose risks to individuals or communities not involved in the research, and lead to public controversy. It is therefore essential to ensure that the risks of CHI studies are justified by their social value—that is, their potential to generate benefits for society—and that public trust can be maintained. In this paper, we aim to clarify how research sponsors, research ethics committees and other reviewers should judge the social value of CHI studies. We develop a list of relevant considerations for making social value judgments based on the standard view of social value. We then use this list to discuss the example of potentially conducting dengue virus CHI studies in endemic settings. We argue that dengue virus CHI studies in endemic settings would fall on the higher end of the spectrum of social value, mostly because of their potential to redirect all fields of future dengue research. Drawing on this discussion, we derive several general recommendations for how reviewers should judge the social value of CHI studies. (shrink)

In the early 1990s, Microcebus murinus, a small primate endemic to Madagascar, emerged as a potential animal model for the study of aging and Alzheimer’s disease. This paper traces the use of the lesser mouse lemur in research on aging and associated neurodegenerative diseases, focusing on a basic material precondition that made this possible, namely, the conversion of a wild animal into an experimental organism that lives, breeds, and survives in the laboratory. It argues that the “old” mouse (...) lemur model can be considered as an eco-zootechnical acquisition. This is shown by examining how, since the early 1970s, French mouse lemur researchers have articulated colony productivity and viability with the influence of environmental factors on the demographics and physiology of the species. The appearance and maintenance of a growing number of old mouse lemurs in French research facilities are related to three developments: the application of the ecological notion of “social stress” to the understanding and management of the behavior of the captive population; the experimental demonstration that a variety of seasonal physiological changes in the species were influenced by the photoperiod; and the related attempt to accelerate aging in mouse lemurs through the manipulation of annual light conditions. (shrink)

This article discusses the history of rabies in South Africa since the early twentieth century. It argues that rabies is a zoonotic disease that traverses rural and urban spaces, that transfers itself between wild and domestic animals and remains a potential threat to human life in the region. Scientists discovered an indigenous form of rabies, found primarily in the yellow mongoose, after the first biomedically confirmed human fatalities in 1928. Since the 1950s canine rabies, presumed to have moved southwards (...) from across the Zambezi River, has become endemic also. South Africa is home to a comparatively large number of rabies strains and animal carriers, making it a particularly interesting case study. Environmental changes during the colonial and apartheid periods have helped to explain the increase in rabies cases since the midtwentieth century. Moreover, developments in the biological and ecological sciences have provided insights into why the rabies virus has become endemic in certain wildlife species. (shrink)

During the mid-twentieth century, Soviet scientists developed the “natural focus” theory–practice framework to explain outbreaks of diseases endemic to wild animals and transmitted to humans. Focusing on parasitologist-physician Evgeny N. Pavlovsky and other field scientists’ work in the Soviet borderlands, this article explores how the natural focus framework’s concepts and practices were entangled in political as well as material ecologies of knowledge and practice. We argue that the very definition of endemic plague incorporated both hands-on materialist experience and (...) ideological concepts that supported Soviet colonization. Theorizing and fighting plague assisted with the goals of controlling and improving landscapes and peoples in southern Russia and Central Asia. The history of the natural focus framework illustrates how Soviet disease ecology co-developed with the needs of local and central political powers in the Soviet borderlands. (shrink)

BackgroundThe consent process for a genetic study is challenging when the research is conducted in a group stigmatized because of beliefs that the disease is familial. Podoconiosis, also known as 'mossy foot', is an example of such a disease. It is a condition resulting in swelling of the lower legs among people exposed to red clay soil. It is a very stigmatizing problem in endemic areas of Ethiopia because of the widely held opinion that the disease (...) runs in families and is untreatable. The aim of this study was to explore the impact of social stigma on the process of obtaining consent for a study on the genetics of podoconiosis in Southern Ethiopia.MethodsWe adapted a rapid assessment tool validated in The Gambia. The methodology was qualitative involving focus-group discussions (n = 4) and in-depth interviews (n = 25) with community members, fieldworkers, researchers and staff of the Mossy Foot Treatment and Prevention Association (MFTPA) working on prevention and treatment of podoconiosis.ResultsWe found that patients were afraid of participation in a genetic study for fear the study might aggravate stigmatization by publicizing the familial nature of the disease. The MFTPA was also concerned that discussion about the familial nature of podoconiosis would disappoint patients and would threaten the trust they have in the organization. In addition, participants of the rapid assessment stressed that the genetic study should be approved at family level before prospective participants are approached for consent. Based on this feedback, we developed and implemented a consent process involving community consensus and education of fieldworkers, community members and health workers. In addition, we utilized the experience and established trust of the MFTPA to diminish the perceived risk.ConclusionThe study showed that the consent process developed based on issues highlighted in the rapid assessment facilitated recruitment of participants and increased their confidence that the genetic research would not fuel stigma. Therefore, investigators must seek to assess and address risks of research from prospective participants' perspectives. This involves understanding the issues in the society, the culture, community dialogues and developing a consent process that takes all these into consideration. (shrink)

Extent health humanities readings of Gabriel García Márquez’s _Love in the Time of Cholera_ have focused on the doctor-patient relationship, the physician-scientist as a model for aspiring practitioners, and how individuals relate to the novel’s health themes of death, disease, and disability. However, such medicine-focused readings neglect the population-level public health concerns of the novel as they relate to contagion, community, and quarantine. This paper contributes to the growing field of public health humanities by using a close reading method (...) to explore how the competing endemic and epidemic public health issues shape the plot and metaphors of the novel. (shrink)

The use of placebos in randomised controlled trials is a subject of considerable ethical debate. In this paper we present a set of considerations to evaluate the ethics of placebo controlled trials that includes: social value of the study; need for a randomised controlled trial and placebo; standards of care; risks of harm due to administration of placebo and the harm benefit balance; clinical equipoise; and double standards. We illustrate the application of these considerations using a case study of a (...) large ongoing multicentre, placebo-controlled, double-blinded, randomised trial to determine primaquine anti-relapse efficacy in vivax malaria. There is an urgent need for primaquine anti-relapse studies in order to rationalise the management of a potentially fatal disease. An ethical justification for the use of the placebo arm is provided on the grounds that the actual current applied standard of care in most endemic places does not include primaquine. It has also been argued that there is clinical equipoise among the primaquine study arms and that the risk of harms of being in the placebo arm is the risk of having relapse, which is no more than not being included in the trial, and that there are no double standards. Based on our set of considerations, we conclude that a placebo arm is not only justified but imperative in this study. We propose that similar considerations should be prospectively applied to other placebo controlled trials and observational control arms where no treatment is offered. (shrink)

A Karger 'Publishing Highlights 1890-2015' title This 2nd, revised edition is still the reference work available in print and electronically on Paracelsus by the Paracelsus authority. Furthermore, it makes a very good read. See also Pagel's last book The Smiling Spleen on Paracelsianism as a historical phenomenon. '...a work in the brilliant tradition of biographical research... even the casual reader will be impressed to learn that, four centuries ago, the man who had the courage to burn in public the writings (...) of Avicenna, recognised pulmonary disease in miners as an occupational hazard, cretinism and goitre as endemic in certain areas, and chorea and hysteria as manifestations of disease, not demonic possession.' The Lancet. (shrink)

BackgroundLittle is known about volunteers from Northern research settings who participate in vaccine trials of highly infectious diseases with no approved treatments. This article explores the motivations of HIV immunocompromised study participants in Canada who volunteered in a Phase II clinical trial that evaluated the safety and immunogenicity of an Ebola vaccine candidate.MethodsObservation at the clinical study site and semi-structured interviews employing situational and discursive analysis were conducted with clinical trial participants and staff over one year. Interviews were recorded, transcribed (...) and analysed using critical qualitative interpretivist thematic analytical techniques. Patterns were identified, clustered and sorted to generate distinct and comprehensive themes. We then reassembled events and contexts from the study participants’ stories to develop two ideal portraits based on "composite characters" based on study participants features. These provide ethnographically rich details of participants’ meaningful social worlds while protecting individual identities.ResultsTen of the 14 clinical trial participants, and 3 study staff were interviewed. Participant demographics and socio-economic profiles expressed limited contextual diversity. Half were men who have sex with men, half were former injection drug users experiencing homelessness, one was female, none were racialized minorities and there were no people from HIV endemic countries. Fully 90% had previous involvement in other clinical studies. Their stories point to particular socio-economic situations that motivated their participation as clinical labor through trial participation.ConclusionsOur findings support Fisher’s argument of “structural coercion” in clinical trial recruitment of vulnerable individuals experiencing precarious living conditions. Clinical trials should provide more detail of the structural socio-economic conditions and healthcare needs which lie “under consent” of study participants. Going well beyond an overly convenient narrative of altruism, ethical deliberation frameworks need to sufficiently address the structural conditions of clinical trials. We offer concrete possibilities for this and acknowledge that further research and clinical data should be made available underlying study participant contexts with regards to recruitment and participation in resource poor settings, in both the South and the North. (shrink)

In this article, we investigated a deterministic model of pneumonia-meningitis coinfection. Employing the Atangana–Baleanu fractional derivative operator in the Caputo framework, we analyze a seven-component approach based on ordinary differential equations. Furthermore, the invariant domain, disease-free as well as endemic equilibria, and the validity of the model’s potential results are all investigated. According to controller design evaluation and modelling, the modulation technique devised is effective in diminishing the proportion of incidences in various compartments. A fundamental reproducing value is (...) generated by exploiting the next generation matrix to assess the properties of the equilibrium. The system’s reliability is further evaluated. Sensitivity analysis is used to classify the impact of each component on the spread or prevention of illness. Using simulation studies, the impacts of providing therapy have been determined. Additionally, modelling the appropriate configuration demonstrated that lowering the fractional order from 1 necessitates a rapid initiation of the specified control technique at the largest intensity achievable and retaining it for the bulk of the pandemic’s duration. (shrink)

This issue of the Journal of Medical covers a range of ethical issues and care settings making the task of beginning to summarise these papers challenging. They reflect the diversity of our field, representing different branches of bioethics focussing on specific areas or topics using a variety of methodologies: but how do we categorise these branches of bioethics? What demarks one branch from another? And what function do such categorisations fulfil? From the early days of medical ethics we now have (...) a growing proliferation of different branches, from those with a more specific focus: clinical ethics, global ethics, nursing ethics, public health ethics for example, to a widening out, in terms of bioethics becoming the broader usage and medical ethics sitting within that. More recently, a new area of ethical focus has arisen, One Health, the subject of Johnson and Degeling’s article in this issue. They define One Health as follows: ‘One Health is generally construed as an integrated approach to understanding and managing disease. Although primarily associated with the prevention and control of Emerging Infectious Diseases, the approach is also relevant to dealing with endemic and zoonotic animal diseases, as well as securing food safety. In its most comprehensive form, it extends to fostering the health of humans, animals and their shared environments.’ This raises, in many ways, a different set of ethical concerns from those usually encountered in bioethics and medical ethics and this leads Johnson and Degeling to ask whether One Health merits having its own ‘ethical framework’. They use ethical frameworks in two senses: as value neutral deliberative tools and as embodying values, and consider how each usage could be applied in One Health. In terms of the first usage they state: ‘When ethical frameworks are regarded as a procedural tool then, the One Health perspective can broaden …. (shrink)

Rift Valley Fever is a vector-borne disease mainly transmitted by mosquito. To gain some quantitative insights into its dynamics, a deterministic model with mosquito, livestock, and human host is formulated as a system of nonlinear ordinary differential equations and analyzed. The disease threshold $$\mathcal{R}_0$$ is computed and used to investigate the local stability of the equilibria. A sensitivity analysis is performed and the most sensitive model parameters to the measure of initial disease transmission $$\mathcal{R}_0$$ and the (...) class='Hi'>endemic equilibrium are determined. Both $$\mathcal{R}_0$$ and the disease prevalence in mosquitoes are more sensitive to the natural mosquito death rate, d m . The disease prevalence in livestock and humans are more sensitive to livestock and human recruitment rates, $$\Uppi_l$$ and $$\Uppi_h$$, respectively, suggesting isolation of livestock from humans is a viable preventive strategy during an outbreak. Numerical simulations support the analytical results in further exploring theoretically the long-term dynamics of the disease at the population level. (shrink)

Here, an epidemiological model considering pro and anti-vaccination groups is proposed and analyzed. In this model, susceptible individuals can migrate between these two groups due to the influence of false and true news about safety and efficacy of vaccines. From this model, written as a set of three ordinary differential equations, analytical expressions for the disease-free steady state, the endemic steady state, and the basic reproduction number are derived. It is analytically shown that low vaccination rate and no (...) influx to the pro-vaccination group have similar impacts on the long-term amount of infected individuals. Numerical simulations are performed with parameter values of the COVID-19 pandemic to illustrate the analytical results. The possible relevance of this work is discussed from a public health perspective. (shrink)

To date, our knowledge of Rift Valley fever disease spread and maintenance is still limited, as flooding, humid weather and presence of biting insects such as mosquitoes, have not completely explained RVF outbreaks. We propose a model that includes livestock, mosquitoes and ticks compartments structured according to their questing and feeding behaviour in order to study the possible role of ticks on the dynamics of RVF. To quantify disease transmission at the initial stage of the epidemic, we derive (...) an explicit formula of the basic reproductive number, $$R_0$$ R 0. Using the concept of Metzler matrix, we state necessary conditions for global asymptotic stability of the disease-free equilibrium. Results suggest that although host-ticks interactions may serve as disease reservoirs or disease amplifiers, the Aedes reproductive number should be kept under unity if disease post-epizootics activities are to be controlled. Results of both local and global sensitivity analysis of selected model parameters indicate that $$R_0$$ R 0 is more sensitive to the ticks attachment and detachment rates, probability of transmission from ticks to host and from host to ticks, length of infection in livestock and ticks death rate. Furthermore, when comparing the mean value of $$R_0$$ R 0 with that from previous studies which did not include ticks we found that our $$R_0$$ R 0 is very much larger resulting in an increase in the exponential phase of an outbreak. These findings suggest that if ticks are capable of transmitting the virus, they may be contributing to disease outbreaks and endemicity. (shrink)

In this study, for COVID-19, we divide people into four categories: susceptible S t, closely contacted C t, infective I t, and removed R t according to the current epidemic situation and then investigate two models: the SCIR models with immigration and without immigration. For the former, Model 1, we obtain the condition for global stability of its disease-free equilibrium. For the latter, Model 2, we establish the local asymptotic stability of its endemic equilibrium by constructing Lyapunov function. (...) Afterwards, by the bifurcation theory, we qualitatively analyze the properties of its Hopf bifurcations of the latter. Finally, numerical simulations are given to illustrate the obtained results of two models. The results imply the importance of finding closely contacted and overseas imports on epidemic control. It indicates that not only the incubation delay τ is crucial for the containment of the COVID-19 but also the scientific and rigorous containment measures are the key factors of the success of the containment. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:The Limits of Our ObligationsRyan C. MavesDisclaimers. No funding was utilized for this manuscript. Dr. Maves is a retired U.S. Navy officer, and the opinions contained herein are his own. The opinions in this manuscript do not reflect the official opinion of the Department of the Navy, Department of Defense, nor of the U.S. Government.In 2012, I was a commander in the United States Navy, deployed to the NATO (...) Role 3 Multinational Medical Unit in Kandahar Airfield (KAF), Afghanistan. The KAF Role 3 began as a tent hospital under Canadian command, built along the flight line at Ahmad Shah Baba International Airport as [End Page 176] part of an expanding NATO base. By the time of my arrival, it was a small but capable brick-and-mortar building under U.S. Navy command, with four operating rooms, two CT scanners, and a busy intensive care unit (ICU).Not long before my deployment, the KAF Role 3 was described as one of the busiest trauma hospitals in the world. Casualties arrived every day, usually by helicopter. Blast injuries from improvised explosive devices (IEDs) were common, ranging in severity from concussions in passengers in armored vehicles, to multiple amputations from blast injuries with concomitant thoracic, abdominal, and pelvic trauma. KAF had a daytime population of over 30,000 in 2012, and our hospital was effectively the referral center for the region, so patients with non-surgical diagnoses were similarly common: myocardial infarctions, seizures, pulmonary emboli, and endemic infections, to name a few.As an infectious disease (I.D.) specialist, I functioned mainly as a hospitalist, managing patients postoperatively, but I also provided any consultative support when needed. During mass casualty events, the intensivists and I would act as backups in the trauma bay, freeing up the surgeons for the most acutely injured patients. It turned out that an I.D. doctor’s skillset lent itself well to acute trauma evaluations; we are well known for having an eye for fine details, combined with low-grade paranoia. These traits served me well during what I came to describe as “my involuntary trauma fellowship.”Our patients could be divided into five key groups: Afghan National Security Forces (ANSF, including the army and national police), non-Afghan coalition military (mostly U.S. and other NATO members), Afghan civilians, NATO civilian contract staff, and the Taliban. Our approach to each of these groups was different. For all patient groups, we would provide the same emergency care, including acute resuscitation and immediate life-saving surgery. It was after this emergency care period that our management plans diverged.For coalition forces, our next priority after acute resuscitation and stabilization was to assess whether a patient could remain in theater. Stable patients with relatively minor injuries could often undergo rehabilitation at KAF; many personnel could subsequently return to combat duty with their units. More seriously-injured patients would be transported out of Afghanistan within 24-48 hours (if not faster). Usually, this would involve stops at Bagram Airfield near Kabul and then Landstuhl Regional Medical Center in Germany before reaching a military hospital in their home countries. There were few limits on whom could be transported. Dedicated critical care air transport teams (CCATT) included intensivists, respiratory therapists, and critical care nurses, who could manage the most unstable patients on board what was effectively a flying ICU. The “lung team” in Landstuhl could fly to KAF to start patients with severe respiratory failure on extracorporeal membrane oxygenation (ECMO) and then fly them out on maximal support.NATO civilian contractors would receive comparable care, although the exact details of how they would be transported out of theater would depend on their home countries and the nature of their contract. We cared for one civilian contractor with newly-diagnosed HIV infection whom we were able to stabilize on the ventilator, get him extubated, start on initial antiretroviral therapy, and transport him home with a referral to his local HIV care program.Afghan soldiers were part of the coalition, but there was no distant home country where we could transport them. They were home. After their resuscitations and surgeries, we would arrange transfer to the Kandahar Regional... (shrink)

To mitigate the spread of schistosomiasis, a deterministic human-bovine mathematical model of its transmission dynamics accounting for contaminated water reservoirs, including treatment of bovines and humans and mollusciciding is formulated and theoretically analyzed. The disease-free equilibrium is locally and globally asymptotically stable whenever the basic reproduction number R0<1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$R_0<1$$\end{document}, while global stability of the endemic equilibrium is investigated by constructing a suitable Lyapunov function. To support the analytical results, parameter values (...) from published literature are used for numerical simulations and where applicable, uncertainty analysis on the non-dimensional system parameters is performed using the Latin Hypercube Sampling and Partial Rank Correlation Coefficient techniques. Sensitivity analysis to determine the relative importance of model parameters to disease transmission shows that the environment-related parameters namely, εs\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varepsilon _s$$\end{document} (snails shedding rate of cercariae), ps\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$p_s$$\end{document} (probability that cercariae shed by snails survive), c (fraction of the contaminated environment sprayed by molluscicides) and μc\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mu _c$$\end{document} (mortality rate of cercariae) are the most significant to mitigate the spread of schistosomiasis. Mollusciciding, which directly impacts the contaminated environment as a single control strategy is more effective compared to treatment. However, concurrently applying mollusciciding and treatment will yield a better outcome. (shrink)

Schistosomiasis, a vector-borne chronically debilitating infectious disease, is a serious public health concern for humans and animals in the affected tropical and sub-tropical regions. We formulate and theoretically analyze a deterministic mathematical model with snail and bovine hosts. The basic reproduction number R0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$R_0$$\end{document} is computed and used to investigate the local stability of the model’s steady states. Global stability of the endemic equilibrium is carried out by constructing a suitable (...) Lyapunov function. Sensitivity analysis shows that the basic reproduction number is most sensitive to the model parameters related to the contaminated environment, namely: shedding rate of cercariae by snails, cercariae to miracidia survival probability, snails-miracidia effective contact rate and natural death rate of miracidia and cercariae. Numerical results show that when no intervention measures are implemented, there is an increase of the infected classes, and a rapid decline of the number of susceptible and exposed bovines and snails. Effects of the variation of some of the key sensitive model parameters on the schistosomiasis dynamics as well as on the initial disease transmission threshold parameter R0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$R_0$$\end{document} are graphically depicted. (shrink)

The greatest risks of Covid-19 are not arising from its direct effects on morbidity and mortality but from exaggerated aspirations to control such effects politically. A swift transformation from an epidemic to an endemic state of affairs may in case of a disease with comparatively low and unequally distributed mortality like covid-19 be an option, too. This needs to be laid out but it is not the task of science to plead for this or any other option.

ABSTRACT This paper focuses on poverty and inequality in the world today. First, it points out how this topic is a main concern for the IAB. Second, it proposes ‘new’ theoretical tools in order to analyze global justice and our obligations towards the needy. I present John Rawls's denial that the egalitarian principle can be applied to the global sphere, his proposed weak duty of assistance, and his consideration of endemic poverty as essentially homegrown. In opposition, I focus on (...) Thomas Pogge as representative of a cosmopolitan view who also holds a critical position towards the international systems which allow and cause poverty. I endorse the general normative proposal that defends every human being as an ultimate unit of moral concern, as well as the strategy of moving away from the charity model of bilateral aid to the realm of rights and duties. These ideas should redesign and broaden the normative and practical roles of institutions, and should also help provide a new approach on bioethical issues such as drug patenting or the imbalance in global research and neglected diseases. (shrink)

At the end of the 1920s, Tanganyika Territory experienced several serious rodent outbreaks that threatened cotton and other grain production. At the same time, regular reports of pneumonic and bubonic plague occurred in the northern areas of Tanganyika. These events led the British colonial administration to dispatch several studies into rodent taxonomy and ecology in 1931 to determine the causes of rodent outbreaks and plague disease, and to control future outbreaks. The application of ecological frameworks to the control of (...) rodent outbreaks and plague disease transmission in colonial Tanganyika Territory gradually moved from a view that prioritised 'ecological interrelations' among rodents, fleas and people to one where those interrelations required studies into population dynamics, endemicity and social organisation in order to mitigate pests and pestilence. This shift in Tanganyika anticipated later population ecology approaches on the African continent. Drawing on sources from the Tanzania National Archives, this article offers an important case study of the application of ecological frameworks in a colonial setting that anticipated later global scientific interest in studies of rodent populations and rodent-borne disease ecologies. (shrink)

Neospora caninum infection, one of the major causes of abortions in dairy cattle, has brought a huge loss to farmers worldwide. In this study, we develop a six-compartment susceptible-infected model of N. caninum transmission which is later reduced to a two-equation system. Potential controls including medication, test-and-cull, and vaccination are proposed and analyzed, and the corresponding reproduction numbers are derived. The conditions for the global stabilities of disease-free and endemic equilibria are investigated with analytical solutions and geometric approach. (...) Furthermore, uncertainty and sensitivity analysis shows that three control strategies are effective towards the varied environment, whereas the effectiveness of each measure highly depends on parameters related to control actions. Dynamics of reproduction numbers illustrate that disease elimination can be achieved by three types of controls: adopting medication with medicine efficacy higher than 0.4 to prevent vertical transmission, implementing test-and-cull with culling coverage larger than 0.3, and taking vaccine with coverage larger than 0.1. Numerical results suggest that preventive measures should at least include the prevention of access of other hosts, such as dogs, to cattle; otherwise, these control measures will lose effectiveness. Our presented study provides guidance for decision-making on N. caninum infected farm management. (shrink)