No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Modeling Vector-Borne Diseases in a Commoditized Landscape
Abstract
As Mandal et al. (2011) review, there is a rough hierarchy of models for vector-borne disease, focusing on malaria. These range from Ross (1911) through Macdonald (1957) to Anderson and May (1991), who present, respectively, two-, three-, and four-dimensional models. Macdonald and Anderson-May extend the Ross model to include latent periods in both human and vector. Further extensions explore the role of immune competence, superinfection, pathogen evolution, host and mosquito behavior, migration, population age structure, spatial dynamics, environmental factors, and so on, all largely variations on the Ross and Macdonald theme (Reiner et al. 2013). Yang (2000) studies a model containing ten differential equations.
ResearchGate has not been able to resolve any citations for this publication.
Black-and-gold howler monkeys Alouatta caraya, are arboreal primates, inhabitants of Neotropical forests, highly susceptible to the yellow fever virus, considered early 'sentinels' of outbreaks, and thus, of major epidemiological importance. Currently, anthropogenic habitat loss and modifications threatens their survival. Habitat modification can prevent, reduce or change dispersal behavior, which, in turn, may influence patterns of gene flow. We explored past and contemporary levels of genetic diversity, elucidated genetic structure and identified its possible drivers, in ten populations (n = 138) located in the southernmost distribution range of the species in South America, in Argentina and Paraguay. Overall, genetic variability was moderate (ten microsatellites: 3.16 ± 0.18 alleles per locus, allelic richness of 2.93 ± 0.81, 0.443±0.025 unbiased expected heterozygosity; 22 haplotypes of 491-bp mitochondrial Control Region, haplotypic diversity of 0.930 ± 0.11, and nucleotide diversity of0.01± 0.007). Significant evidence of inbreeding was found in a population that was, later, decimated by yellow fever. Population-based gene flow measures (FST = 0.13; θST = 018), hierarchical analysis of molecular variance and Bayesian clustering methods revealed significant genetic structure, grouping individuals into four clusters. Shared haplotypes and lack of mitochondrial differentiation (non-significant θST) among some populations seem to support the hypothesis of historical dispersal via riparian forests. Current resistance analyses revealed a significant role of landscape features in modeling contemporary gene flow: continuous forest and riparian forests could promote genetic exchange, whereas disturbed forests or crop/grassland fields may restrict it. Estimates of effective population size allow anticipating that the studied populations will lose 75% of heterozygosity in less than 50 generations. Our findings suggest that anthropogenic modifications on native forests, increasingly ongoing in Northeastern Argentina, Southern Paraguay and Southeastern Brazil, might prevent the dispersal of howlers, leading to population isolation. To ensure long-term viability and maintain genetic connectivity of A. caraya remnant populations, we recommend preserving and restoring habitat continuity. To conserve the species genetic pool, as well, the four genetic clusters identified here should be considered separate Management Units and given high conservation priority. In light of our findings and considering complementary non-genetic information, we suggest upgrading the international conservation status of A. caraya to “Vulnerable”.
Asia is considered an important source of influenza A virus (IAV) pandemics, owing to large, diverse viral reservoirs in poultry and swine. However, the zoonotic origins of the 2009 A/H1N1 influenza pandemic virus (pdmH1N1) remain unclear, due to conflicting evidence from swine and humans. There is strong evidence that the first human outbreak of pdmH1N1 occurred in Mexico in early 2009. However, no related swine viruses have been detected in Mexico or any part of the Americas, and to date the most closely related ancestor viruses were identified in Asian swine. Here, we use 58 new whole-genome sequences from IAVs collected in Mexican swine to establish that the swine virus responsible for the 2009 pandemic evolved in central Mexico. This finding highlights how the 2009 pandemic arose from a region not considered a pandemic risk, owing to an expansion of IAV diversity in swine resulting from long-distance live swine trade.
Zika virus (ZIKV) is a mosquito-borne flavivirus that has recently been responsible for a serious outbreak of disease in South and Central America. Infection with ZIKV has been associated with severe neurological symptoms and the development of microcephaly in unborn fetuses. Many of the regions involved in the current outbreak are known to be endemic for another flavivirus, dengue virus (DENV), which indicates that a large percentage of the population may have pre-existing DENV immunity. Thus, it is vital to investigate what impact pre-existing DENV immunity has on ZIKV infection. Here, we use primary human myeloid cells as a model for ZIKV enhancement in the presence of DENV antibodies. We show that sera containing DENV antibodies from individuals living in a DENV-endemic area are able to enhance ZIKV infection in a human macrophage-derived cell line and primary human macrophages. We also demonstrate altered pro-inflammatory cytokine production in macrophages with enhanced ZIKV infection. Our study indicates an important role for pre-existing DENV immunity on ZIKV infection in primary human immune cells and establishes a relevant in vitro model to study ZIKV antibody-dependent enhancement.
This paper argues that addressing the underlying structural drivers of disease vulnerability is essential for a ‘One Health’ approach to tackling zoonotic diseases in Africa. Through three case studies—trypanosomiasis in Zimbabwe, Ebola and Lassa fever in Sierra Leone and Rift Valley fever in Kenya—we show how political interests, commercial investments and conflict and securitization all generate patterns of vulnerability, reshaping the political ecology of disease landscapes, influencing traditional coping mechanisms and affecting health service provision and outbreak responses. A historical, political economy approach reveals patterns of ‘structural violence’ that reinforce inequalities and marginalization of certain groups, increasing disease risks. Addressing the politics of One Health requires analysing trade-offs and conflicts between interests and visions of the future. For all zoonotic diseases economic and political dimensions are ultimately critical and One Health approaches must engage with these factors, and not just end with an ‘anti-political’ focus on institutional and disciplinary collaboration.
This article is part of the themed issue ‘One Health for a changing world: zoonoses, ecosystems and human well-being’.
Spatial synchrony, defined as correlated temporal fluctuations among populations, is a fundamental feature of population dynamics, but many aspects of synchrony remain poorly understood. Few studies have examined detailed geographical patterns of synchrony; instead most focus on how synchrony declines with increasing linear distance between locations, making the simplifying assumption that distance decay is isotropic. By synthesising and extending prior work, we show how geography of synchrony, a term which we use to refer to detailed spatial variation in patterns of synchrony, can be leveraged to understand ecological processes including identification of drivers of synchrony, a long-standing challenge. We focus on three main objectives: (1) showing conceptually and theoretically four mechanisms that can generate geographies of synchrony; (2) documenting complex and pronounced geographies of synchrony in two important study systems; and (3) demonstrating a variety of methods capable of revealing the geography of synchrony and, through it, underlying organism ecology. For example, we introduce a new type of network, the synchrony network, the structure of which provides ecological insight. By documenting the importance of geographies of synchrony, advancing conceptual frameworks, and demonstrating powerful methods, we aim to help elevate the geography of synchrony into a mainstream area of study and application.
Emerging infectious diseases were cited as a cause of population decline of wild nonhuman primates (NHPs) by A. Estrada and collaborators in their review “Impending extinction crisis of the world’s primates” (Science Advances, 18 January, e1600946). Concurrent with the publication of this review, an epidemic of jungle yellow fever (YF) in the Atlantic Forest region of southeastern Brazil is affecting humans and NHPs alike, challenging health and wildlife conservation authorities and professionals. From December 2016 to 18 May 2017, YF has killed 264 people (42 additional deaths are under investigation) and caused, at least, 5,000 NHP deaths (1). Our field estimates sum many thousands of NHP deaths. Humans have access to an effective vaccine and about 85% of infected unvaccinated people are asymptomatic or develop a mild form of YF (2). Despite this resistance, there are 758 confirmed human cases and a further 622 cases under investigation, about 63% of them in regions of recommended vaccination prior to the current epidemic.
Transmission of Zika virus (ZIKV) in the Americas was first confirmed in May 2015 in northeast Brazil. Brazil has had the highest number of reported ZIKV cases worldwide (more than 200,000 by 24 December 2016) and the most cases associated with microcephaly and other birth defects (2,366 confirmed by 31 December 2016). Since the initial detection of ZIKV in Brazil, more than 45 countries in the Americas have reported local ZIKV transmission, with 24 of these reporting severe ZIKV-associated disease. However, the origin and epidemic history of ZIKV in Brazil and the Americas remain poorly understood, despite the value of this information for interpreting observed trends in reported microcephaly. Here we address this issue by generating 54 complete or partial ZIKV genomes, mostly from Brazil, and reporting data generated by a mobile genomics laboratory that travelled across northeast Brazil in 2016. One sequence represents the earliest confirmed ZIKV infection in Brazil. Analyses of viral genomes with ecological and epidemiological data yield an estimate that ZIKV was present in northeast Brazil by February 2014 and is likely to have disseminated from there, nationally and internationally, before the first detection of ZIKV in the Americas. Estimated dates for the international spread of ZIKV from Brazil indicate the duration of pre-detection cryptic transmission in recipient regions. The role of northeast Brazil in the establishment of ZIKV in the Americas is further supported by geographic analysis of ZIKV transmission potential and by estimates of the basic reproduction number of the virus.
Significance
Mathematical and computational modeling approaches can be essential in providing quantitative scenarios of disease spreading, as well as projecting the impact in the population. Here we analyze the spatial and temporal dynamics of the Zika virus epidemic in the Americas with a microsimulation approach informed by high-definition demographic, mobility, and epidemic data. The model provides probability distributions for the time and place of introduction of Zika in Brazil, the estimate of the attack rate, timing of the epidemic in the affected countries, and the projected number of newborns from women infected by Zika. These results are potentially relevant in the preparation and analysis of contingency plans aimed at Zika virus control.
Global viral diversity is substantial, but viruses that contribute little to the public health burden or to
agricultural damage receive minimal attention until a seemingly unimportant virus becomes a threat. The Zika
virus (ZIKV) illustrated this, as there was limited information and awareness of the virus when it was identified
as a public health emergency in February 2016. Predicting which virus may pose a future threat is difficult. This
is in part because significant knowledge gaps in the basic biology and ecology of an emerging virus can impede
policy development, delay decision making, and hinder public health action. We suggest using a phylogenetic
framework of pathogens and their infected host species for insight into which animals may serve as reservoirs.
For example, examining flaviviruses closely related to ZIKV, the phylogenetic framework indicates New World
monkeys are the most likely candidates to be potential reservoirs for ZIKV. Secondarily, mammals that are in
close proximity to humans should be considered because of the increased opportunity for pathogen exchange.
The increase in human-mediated environmental change is accelerating the probability of another previously
overlooked virus becoming a significant concern. By investing in basic science research and organizing our
knowledge into an evolutionary framework, we will be better prepared to respond to the next emerging
infectious disease.
Deforestation continues across the tropics at alarming rates, with repercussions for ecosystem processes, carbon storage and long term sustainability. Taking advantage of recent fine-scale measurement of deforestation, this analysis aims to improve our understanding of the scale of deforestation drivers in the tropics. To do this we examine trends in forest clearings of different sizes from 2000 – 2012 by country, region and development level. As tropical deforestation increased from approximately 6900 kha / yr in the first half of the study period, to > 7900 kha / yr in the second half of the study period, > 50% of this increase was attributable to increasing medium and large clearings (> 10 ha). This trend was most pronounced in Southeast Asia and in South America. Outside of Brazil > 60% of the observed increase in deforestation in South America was due to increasing medium- and large-scale clearings; Brazil had a divergent trend of decreasing deforestation, > 90% of which was attributable to a reduction in medium and large clearings. The increasing prominence of large-scale drivers of forest loss in many regions and countries suggests the growing need for policy interventions which target industrial-scale agricultural commodity producers. The experience in Brazil suggests that there are promising policy solutions to mitigate large-scale deforestation, but that these policy initiatives do not adequately address small-scale drivers. By providing up-to-date and spatially explicit information on the scale of deforestation, and the trends in these patterns over time, this study contributes valuable information for monitoring, and designing effective interventions addressing, deforestation.
The sudden appearance of overt human Zika virus infections that cross the placenta to damage fetal tissues, target sexual organs, and are followed in some instances by Guillain-Barré syndrome raises questions regarding whether these outcomes are caused by genetic mutations or if prior infection by other flaviviruses affects disease outcome. Because dengue and Zika viruses co-circulate in the urban Aedes aegypti mosquito–human cycle, a logical question, as suggested by in vitro data, is whether dengue virus infections result in antibody-dependent enhancement of Zika virus infections. This review emphasizes the critical role for epidemiologic studies (retrospective and prospective) in combination with the studies to identify specific sites of Zika virus infection in humans that are needed to establish antibody-dependent enhancement as a possibility or a reality.
We evaluated the nosocomial outbreak of Middle East Respiratory Syndrome (MERS) Coronavirus (CoV) in the Republic of Korea, 2015, from a healthcare operations management perspective. Establishment of healthcare policy in South Korea grants patients' freedom to select and visit multiple hospitals. Current policy enforces hospitals preference for multi-patient rooms to single-patient rooms, to lower financial burden. Existing healthcare systems tragically contributed to 186 MERS outbreak cases, starting from single "index patient" into three generations of secondary infections. By developing a macro-level health system dynamics model, we provide empirical knowledge to examining the case from both operational and financial perspectives. In our simulation, under base infectivity scenario, high ER occupancy circumstance contributed to an estimated average of 101 (917%) more infected patients, compared to when in low occupancy circumstance. Economic patient room design showed an estimated 702% increase in the number of infected patients, despite the overall 98% savings in total expected costs compared to optimal room design. This study provides an initial system dynamics model, performance measurements from an operational perspective. Importantly, the intent of this study was to provide evidence to motivate public, private, and government healthcare administrators' recognition of current shortcomings, to optimize performance as a whole system, rather than mere individual aspects.
We study the persistence and extinction of species in a simple food chain that is modelled by a Lotka-Volterra system with environmental stochasticity. There exist sharp results for deterministic Lotka-Volterra systems in the literature but few for their stochastic counterparts. The food chain we analyze consists of one prey and $n-1$ predators. The $j$th predator eats the $j-1$th species and is eaten by the $j+1$th predator; this way each species only interacts with at most two other species - the ones that are immediately above or below it in the trophic chain. We show that one can classify, based on an explicit quantity depending on the interaction coefficients of the system, which species go extinct and which converge to their unique invariant probability measure. Our work can be seen as a natural extension of the deterministic results of Gard and Hallam '79 to a stochastic setting. As one consequence we show that environmental stochasticity makes species more likely to go extinct. However, if the environmental fluctuations are small, persistence in the deterministic setting is preserved in the stochastic system. Our analysis also shows that the addition of a new apex predator makes, as expected, the different species more prone to extinction. Another novelty of our analysis is the fact that we can describe the behavior the system when the noise is degenerate. This is relevant because of the possibility of strong correlations between the effects of the environment on the different species.
Zika virus (ZIKV), a mosquito-borne positive-stranded RNA virus of the family Flaviviridae (genus Flavivirus), is now causing an unprecedented large-scale outbreak in the Americas. Historically, ZIKV spread eastward from equatorial Africa and Asia to the Pacific Islands during the late 2000s to early 2010s, invaded the Caribbean and Central and South America in 2015, and reached North America in 2016. Although ZIKV infection generally causes no symptoms or only a mild self-limiting illness, it has recently been linked to a rising number of severe neurological diseases, including microcephaly and Guillain-Barré syndrome. Because of the continuous geographic expansion of both the virus and its mosquito vectors, ZIKV poses a serious threat to public health around the globe. However, there are no vaccines or antiviral therapies available against this pathogen. This review summarizes a fast-growing body of literature on the history, epidemiology, transmission, and clinical presentation of ZIKV and highlights the urgent need for the development of efficient control strategies for this emerging pathogen.
Tropical forests are undergoing land use change in many regions of the world, including the African continent. Human populations living close to forest margins fragmented and disturbed by deforestation may be particularly exposed to zoonotic infections because of the higher likelihood for humans to be in contact with disease reservoirs. Quantitative analysis of the nexus between deforestation and the emergence of Ebola virus disease (EVD), however, is still missing. Here we use land cover change data in conjunction with EVD outbreak records to investigate the association between recent (2004–2014) outbreaks in West and Central Africa, and patterns of land use change in the region. We show how in these EVD outbreaks the index cases in humans (i.e. spillover from wildlife reservoirs) occurred mostly in hotspots of forest fragmentation.
The reemergence and growing burden of mosquito-borne virus infections have incited public fear and growing research efforts to understand the mechanisms of infection-associated health outcomes and to provide better approaches for mosquito vector control. While efforts to develop therapeutics, vaccines, and novel genetic mosquito-control technologies are underway, many important underlying ecological questions remain that could significantly enhance our understanding and ability to predict and prevent transmission. Here, we review the current knowledge about the transmission ecology of two recent arbovirus invaders, the chikungunya and Zika viruses. We introduce the viruses and mosquito vectors, highlighting viral biology, historical routes of transmission, and viral mechanisms facilitating rapid global invasion. In addition, we review factors contributing to vector global invasiveness and transmission efficiency. We conclude with a discussion of how human-induced biotic and abiotic environmental changes facilitate mosquito-borne virus transmission, emphasizing critical gaps in understanding. These knowledge gaps are tremendous; much of our data on basic mosquito ecology in the field predate 1960, and the mosquitoes themselves, as well as the world they live in, have substantially changed. A concerted investment in understanding the basic ecology of these vectors, which serve as the main drivers of pathogen transmission in both wildlife and human populations, is now more important than ever.
Since Zika virus (ZIKV) was detected in Brazil in 2015, it has spread explosively across the Americas and has been linked to increased incidence of microcephaly and Guillain-Barré syndrome (GBS). In one year, it has infected over 500,000 people (suspected and confirmed cases) in 40 countries and territories in the Americas. Along with recent epidemics of dengue (DENV) and chikungunya virus (CHIKV), which are also transmitted by Aedes aegypti and Ae. albopictus mosquitoes, the emergence of ZIKV suggests an ongoing intensification of environmental and social factors that have given rise to a new regime of arbovirus transmission. Here, we review hypotheses and preliminary evidence for the environmental and social changes that have fueled the ZIKV epidemic. Potential drivers include climate variation, land use change, poverty, and human movement. Beyond the direct impact of microcephaly and GBS, the ZIKV epidemic will likely have social ramifications for women’s health and economic consequences for tourism and beyond.
Background
Malaria control and elimination are challenged by diversity and complexity of the determinants on the international border in the Great Mekong Sub-region. Hekou, a Chinese county on the China–Vietnam border, was used to document Chinese experiences and lessons for malaria control and elimination. Methods
The design was an ecological study. Malaria burden before 1951 and procedures of 64 years (1952–2015) from malaria hyperendemicity to elimination are described. Single and bilinear regression analysis was utilized to analyse the relationship between the annual malaria incidence (AMI) and gross domestic product (GDP), urbanization rate, and banana planting area (BPA). ResultsThere was a huge malaria burden before 1951. AMI was reduced from 358.62 per 1000 person-years in 1953 to 5.69 per 1000 person-years in 1960. A system of primary health services, comprising three levels of county township hospitals and village health stations maintained malaria control and surveillance activities in changing political and social-economic settings. However, potential under-reported of malaria and market-oriented healthcare led to a malaria epidemic in 1987. Strong political commitment reoriented malaria from a control to an elimination programme. High coverage of malaria intervention and population access to intervention was crucial for malaria control and elimination; meanwhile, AMI was closely associated with socio-economic development, correlation coefficients (R) −0.6845 (95% CI −0.7978, −0.6845) for national GDP, −0.7014 (−0.8093, −0.7014) for national urbanization rate and −0.5563 (−0.7147, −0.3437) for BPA. Conclusions
Multifactor, including political commitment, effective interventions, social and economic development and changing ecological environment, and the complicated interactions between these factors contribute to malaria elimination in Hekou County.
Zika virus was discovered in Uganda in 1947 and is transmitted by Aedes mosquitoes, which also act as vectors for dengue and chikungunya viruses throughout much of the tropical world. In 2007, an outbreak in the Federated States of Micronesia sparked public health concern. In 2013, the virus began to spread across other parts of Oceania and in 2015, a large outbreak in Latin America began in Brazil. Possible associations with microcephaly and Guillain-Barré syndrome observed in this outbreak have raised concerns about continued global spread of Zika virus, prompting its declaration as a Public Health Emergency of International Concern by the World Health Organization. We conducted species distribution modelling to map environmental suitability for Zika. We show a large portion of tropical and sub-tropical regions globally have suitable environmental conditions with over 2.17 billion people inhabiting these areas.
This paper highlights the critical importance of evidence on vector-borne diseases (VBD) prevention and control interventions in urban settings when assessing current and future needs, with a view to setting policy priorities that promote inclusive and equitable urban health services. Research should produce knowledge about policies and interventions that are intended to control and prevent VBDs at the population level and to reduce inequities. Such interventions include policy, program, and resource distribution approaches that address the social determinants of health and exert influence at organizational and system levels.
Electronic supplementary material
The online version of this article (doi:10.1186/s40249-016-0198-6) contains supplementary material, which is available to authorized users.
Zika virus (ZIKV) originated and continues to circulate in a sylvatic transmission cycle between non-human primate hosts and arboreal mosquitoes in tropical Africa. Recently ZIKV invaded the Americas, where it poses a threat to human health, especially to pregnant women and their infants. Here we examine the risk that ZIKV will establish a sylvatic cycle in the Americas, focusing on Brazil. We review the natural history of sylvatic ZIKV and present a mathematical dynamic transmission model to assess the probability of establishment of a sylvatic ZIKV transmission cycle in non-human primates and/or other mammals and arboreal mosquito vectors in Brazil. Brazil is home to multiple species of primates and mosquitoes potentially capable of ZIKV transmission, though direct assessment of host competence (ability to mount viremia sufficient to infect a feeding mosquito) and vector competence (ability to become infected with ZIKV and disseminate and transmit upon subsequent feedings) of New World species is lacking. Modeling reveals a high probability of establishment of sylvatic ZIKV across a large range of biologically plausible parameters. Probability of establishment is dependent on host and vector population sizes, host birthrates, and ZIKV force of infection. Research on the host competence of New World monkeys or other small mammals to ZIKV, on vector competence of New World Aedes, Sabethes, and Haemagogus mosquitoes for ZIKV, and on the geographic range of potential New World hosts and vectors is urgently needed. A sylvatic cycle of ZIKV would make future elimination efforts in the Americas practically impossible, and paints a dire picture for the epidemiology of ZIKV and our ability to end the ongoing outbreak of congenital Zika syndrome.
Arboviruses pose a serious threat to public health worldwide, overloading the healthcare system and causing economic losses. These viruses form a very diverse group, and in Brazil, arboviruses belonging to the families Flaviviridae and Togaviridae are predominant. Unfortunately, the number of arboviruses increases in proportion with factors such as deforestation, poor sanitation, climate changes, and introduction of new viruses like Chikungunya virus and Zika virus.
In Brazil, dengue is endemic, along with the presence of other arboviruses. The situation is complicated by the scarcity of diagnostic infrastructure and the absence of approved vaccines for these diseases. Disease control, thus, relies solely on vector control. Therefore, enhanced clinical knowledge and improved general awareness about these arboviruses are indispensable to tackle diagnostic inadequacies.
As evidence linking Zika virus with serious health complications strengthens, public health officials and clinicians worldwide need to know which locations are likely to be at risk for autochthonous Zika infections. We created risk maps for epidemic and endemic Aedes-borne Zika virus infections globally using a predictive analysis method that draws on temperature, precipitation, elevation, land cover, and population density variables to identify locations suitable for mosquito activity seasonally or year-round. Aedes mosquitoes capable of transmitting Zika and other viruses are likely to live year-round across many tropical areas in the Americas, Africa, and Asia. Our map provides an enhanced global projection of where vector control initiatives may be most valuable for reducing the risk of Zika virus and other Aedes-borne infections.
Neoliberalism--the doctrine that market exchange is an ethic in itself, capable of acting as a guide for all human action--has become dominant in both thought and practice throughout much of the world since 1970 or so. Writing for a wide audience, David Harvey, author of The New Imperialism and The Condition of Postmodernity, here tells the political-economic story of where neoliberalization came from and how it proliferated on the world stage. Through critical engagement with this history, he constructs a framework, not only for analyzing the political and economic dangers that now surround us, but also for assessing the prospects for the more socially just alternatives being advocated by many oppositional movements.
A geographical analysis of the AIDS epidemic in the United States requires a reification of the individual by adopting a ‘social physics’ perspective. Carefully employed, spatial aggregation of individual cases circumvents the problem of patient confidentiality, and produces spatial series containing valuable scientific information generally ignored by traditional epidemiologists. The diffusion of AIDS from 1982 to 1990 at the national level provides the setting for a detailed analysis of a major epicenter, the New York Metropolitan Region. Here the space is strongly structured by daily commuter flows, which both focus the epidemic on Manhattan, and provide the detailed mechanisms for the spatially contagious diffusion generalized at the national scale. AIDS rates are highly predictable over time and space from measures of commuting intensity derived from a Markov analysis. This leads to a consideration of a canonical form related to classical diffusion theory, except that spatial homogeneity is now replaced by the complex structures of commuting in the region. Three phases in the epidemic, homosexual, drug injection, and heterosexual are all associated with social and spatial marginalization reflected in the movement of HIV acting as a tracer for social pathologies. Controlling the HIV requires the serious address of such pathologies.
Providing universal food security and conserving biodiversity are prominent challenges facing humanity in the 21st century. Typically, these challenges are believed to involve a trade-off, especially in farming landscapes of the Global South. We conducted a multivariate analysis of social–ecological data from 110 landscapes in the Global South, and found that different system characteristics lead to partly predictable outcomes, resulting either in trade-offs or, unexpectedly, in synergies (mutual benefits) between food security and biodiversity. Specifically, these synergies are fostered by social equity, by reliable access to local land, and by increasing social capital (eg maintenance of traditions) and human capital (eg health). In contrast, we also found high degrees of food security in landscapes with adequate infrastructure, market access, and financial capital, but this increased security came at the expense of biodiversity. Our findings demonstrate that a social–ecological systems perspective can help to identify previously unrecognized synergies between food security and biodiversity conservation.
Beginning to End Hunger presents the story of Belo Horizonte, home to 2.5 million people and the site of one of the world’s most successful city food security programs. Since its Municipal Secretariat of Food and Nutritional Security was founded in 1993, malnutrition in Belo Horizonte has declined dramatically, leading it to serve as an inspiration for Brazil’s renowned Zero Hunger programs. The Municipal Secretariat’s work with local family farmers also offers a glimpse of how food security, rural livelihoods, and healthy ecosystems can be supported together. While inevitably imperfect, Belo Horizonte offers a vision of the path away from food system dysfunction, unsustainability, and hunger. This case study by M. Jahi Chappell shows the vital importance of holistic approaches to food security, offers ideas on how to design successful policies to end hunger, and lays out strategies for making policy change happen. With these tools, we can take the next steps toward achieving similar reductions in hunger and food insecurity elsewhere in the developed and developing worlds.
Urban slums provide conditions that increase the risk of exposure to vector-borne and zoonotic pathogens. Large interventions, such as social and sanitary changes, are a priority but their implementation is challenging. Integration between the multidisciplinary understanding of pathogens’ dynamics and community participatory approaches is a key prevention strategy.
The book is a unique exploration of a spectrum of unexpected analogs to psychopathologies likely to afflict real-time critical systems, written by a specialist in the epidemiology of mental disorders. The purpose of this book is to develop a set of information-theoretic statistical tools for analyzing the instabilities of real-time cognitive systems at those varying scales and levels of organization, with special focus on high level machine function. The book should be of particular interest to both industry and academic scientists, and government regulators, concerned with driverless cars on intelligent roads. Many of the same concerns also afflict high-end automated weapons systems. The book should appeal to students, researchers, and industrial and governmental administrators facing the design, operation, and maintenance of real time critical systems ranging across manufacturing facilities, transportation, finance, and military operations. © 2017 by World Scientific Publishing Co. Pte. Ltd. All rights reserved.
I Preliminaries.- II Semimartingales and Stochastic Integrals.- III Semimartingales and Decomposable Processes.- IV General Stochastic Integration and Local Times.- V Stochastic Differential Equations.- VI Expansion of Filtrations.- References.
This article investigates the contradictions between public health protocols and infection containment efforts concerning Zika virus and reproductive rights. In El Salvador, for example, women are being advised to avoid pregnancy until 2018, at which time local authorities hope that the virus will be under control. This is not so easy, however, as there is limited access to contraception, abortion is illegal in all instances, and women tend to have little household authority. In this article, I examine the policy, legal, and political contradictions related to the global proliferation of Zika virus in the context of ongoing debates about stratified reproduction. This term conceptualizes the phenomenon that accords different values to reproductive tasks undertaken by women in different socioeconomic, cultural, and national contexts. Whereas reproduction and reproductive autonomy tend to be highly respected and protected for relatively privileged women in the Global North, they tend to be much less so for women of the Global South. Furthermore, the adherence to public and private divisions in both national and transnational contexts segregates reproductive rights from the mainstream of political negotiation and public health intervention, and in doing so frustrates progress toward the realization of global reproductive rights.
Background: The first autochthonous Chikungunya virus transmission in Colombia was reported in September 2014. Three months later, every town in the Caribbean region was affected, including the bordering towns of Ovejas and Corozal, in the department of Sucre. The objective of the study was to analyze and compare the temporal dynamics of the outbreak of Chikungunya in two towns of the department of Sucre.
This article suggests an approach to economic-geographic quantification that is relevant to engaging the socionatural blurring of an Anthropocene. It develops representations of commodities and of economies that draw upon concepts of absolute, relative, and relational space to help move beyond legacies of the Nature-Society divide in economic-geographic thought. To supplement familiar ways of knowing commodities as bounded objects with associated single values (prices), the piece rereads input-output approaches, providing accounts of how commodities enfold relations among socionatural phenomena. It quantifies and maps the activities and flows of the global economy in 2007 in terms of their embodied carbon emissions, labor times, and harvested land areas alongside their monetary values. Comparing the perspectives that result, it identifies empirical and theoretical challenges that a political-industrial ecology could help address.
This volume compiles five papers modeling the effects of neoliberal economics on the emergence of Ebola and its aftermath. Neoliberalism is currently the world’s primary economic philosophy. It centers international relations around globalizing laissez-faire economics for multinational companies, promoting free trade, deregulating economic markets, and shifting state expenditures in favor of private property. The multidisciplinary teams represented here place both Ebola Makona, the Zaire Ebola virus variant that has infected 28,000 in West Africa, and Ebola Reston, which is currently emerging in industrial hog farms in the Philippines and China, within a multi-plank modeling framework. Using a stochastic extinction model that one group spatializes, environmental stochasticity across the ecologies in which Ebola evolves is treated as an ecosystemic prophylaxis. An agroecological logic gate is developed for epidemic control. A Black-Scholes model explicitly links economic margins across agricultural systems to success in biocontrol. This new control theory is further developed around the data-rate and rate-distortion theorems, a turbulence model, and cognitive symmetry breaking. Lastly, a model of pandemic penetrance is used to explore the domino effects of serious outbreaks amplifying through the cascades of disasters that can follow deadly pandemics. All the models presented are contextualized by socioeonomic geographies specific to outbreak locales.Together the models suggest shifts in regional agroeconomics under the neoliberal doctrine, driving deforestation and monoculture production, destroying the ecosystemic “friction” with which local forests typically disrupt Ebola transmission. The resulting collapse in such an ecological function accelerates pathogen spillover and propagation across the remaining host populations. The failure on the part of current control efforts to assimilate such a structural context may render even an efficacious vaccine dysfunctional. The authors propose an alternate science of disease and an adjunct program of interventions useful to researchers and public health officials alike.
This article charts the diverse pathways through which austerity and other policy shifts associated with neoliberalism have come to be embodied globally in ill-health. It combines a review of research on these processes of embodiment with the development of a theory of the resulting forms of biological sub-citizenship. This theory builds on other studies that have already sought to complement and complicate the concept of biological citizenship with attention to the globally uneven experience and embodiment of bioinequalities. Focused on the unevenly embodied sequelae of austerity, the proceeding theorization of biological sub-citizenship is developed in three stages of review and conceptualization: 1) Biological sub-citizenship through exclusion and conditionalization; 2) Biological sub-citizenship through extraction and exploitation; and 3) Biological sub-citizenship through financialized experimentation. In conclusion the paper argues that the analysis of biological sub-citizenship needs to remain open-ended and relational in order to contribute to socially-searching work on the social determinants of health.
This chapter focuses on the impacts of changing climate on arthropod vectors of disease, their relationship with the pathogens they transmit, and the implications of these phenomena for disease transmission,ceteris paribus, that is, assuming everything else stays the same. It introduces a case study that illustrates some of the complexities present when untangling the potential role of climate change on the distribution of disease vectors. Useful concepts to study impacts of climate change on insect vectors of disease are illustrated with this study on changes in the distribution of two major globally invasive vectors: Aedes albopictus and Aedes japonicus, facing the emergence of Aedes flavopictus, formerly a rare species along an altitudinal gradient in Nagasaki, Japan. The basic pattern that has been observed regarding the impact of temperature on pathogens developing inside vectors of disease is that the extrinsic incubation period (EIP).
Urbanization and climate change are the two major environmental challenges of the 21st century. The dramatic expansion of cities around the world creates new conditions for the spread, surveillance, and control of infectious diseases. In particular, urban growth generates pronounced spatial heterogeneity within cities, which can modulate the effect of climate factors at local spatial scales in large urban environments. Importantly, the interaction between environmental forcing and socioeconomic heterogeneity at local scales remains an open area in infectious disease dynamics, especially for urban landscapes of the developing world. A quantitative and conceptual framework on urban health with a focus on infectious diseases would benefit from integrating aspects of climate forcing, population density, and level of wealth. In this paper, we review what is known about these drivers acting independently and jointly on urban infectious diseases; we then outline elements that are missing and would contribute to building such a framework.
Mosquitoes transmit many viruses to a variety of hosts. Cycles of mosquito borne arbovirus transmission are the result of complex interactions between the mosquito, the arbovirus and the host that are influenced by genetic variations in a variety of traits in each that are all influenced by many environmental factors. R0, the basic reproduction number or mean number of individuals infected from a single infected individual, is a measure of mosquito borne arbovirus transmission. Understanding the causes for the distribution of R0 in any transmission cycle is a daunting challenge due to the lack of information on the genetic and environmental variances that influence R0. Information about the major factors influencing R0 for specific transmission cycles is essential to develop efficient and effective strategies to reduce transmission in different cycles and locations.
The conclusion highlights the major contributions of the book both for anthropologists and for public-health practitioners. By focusing on both bodies and the urban landscapes they inhabit, I emphasize the particularities of dengue in Ciudad Sandino to understand how the regulation of human and nonhuman life produces specific forms of belonging and exclusion. I suggest that the politics of life in emerging infectious-disease complexes is as much about ecologically imagined, multispecies communities—about landscapes that include people and mosquitoes and garbage and viruses—as it is about biomedically imagined human bodies. While much of contemporary global health orients itself to the future, seeking ways to anticipate or head off pandemics, I believe that anthropology’s role should be a bit different. In order to critically examine global health, we cannot be futurists. Rather, for anthropologists, understanding dengue and diseases like it entails trailing, working from behind (or even along with) pathogens and vectors and people, gathering knowledge from the traces they—and we—leave. These traces, I argue, play a significant role in how we think of health.
The complexity and connectedness of eco-social processes have major influence on the emergence and spread of infectious diseases amongst humans and animals. The disciplinary nature of most research activity has made it difficult to improve our understanding of interactions and feedback loops within the relevant systems. Influenced by the One Health approach, increasing efforts have recently been made to address this knowledge gap. Disease emergence and spread is strongly influenced by host density and contact structures, pathogen characteristics and pathogen population and molecular evolutionary dynamics in different host species, and host response to infection. All these mechanisms are strongly influenced by eco-social processes, such as globalization and urbanization, which lead to changes in global ecosystem dynamics, including patterns of mobility, human population density and contact structures, and food production and consumption. An improved understanding of epidemiological and eco-social processes, including their interdependence, will be essential to be able to manage diseases in these circumstances. The interfaces between wild animals, domestic animals and humans need to be examined to identify the main risk pathways and put in place appropriate mitigation. Some recent examples of emerging infectious disease are described to illustrate eco-social processes that are influencing disease emergence and spread.