Animal sentinels for environmental and public health

Zoonotic spillover and viral mutations from low and middle-income countries: improving prevention strategies and bridging policy gaps

The increasing frequency of zoonotic spillover events and viral mutations in low and middle-income countries presents a critical global health challenge. Contributing factors encompass cultural practices like bushmeat consumption, wildlife trade for traditional medicine, habitat disruption, and the encroachment of impoverished settlements onto natural habitats. The existing "vaccine gap" in many developing countries exacerbates the situation by allowing unchecked viral replication and the emergence of novel mutant viruses. Despite global health policies addressing the root causes of zoonotic disease emergence, there is a significant absence of concrete prevention-oriented initiatives, posing a potential risk to vulnerable populations. This article is targeted at policymakers, public health professionals, researchers, and global health stakeholders, particularly those engaged in zoonotic disease prevention and control in low and middle-income countries. The article underscores the importance of assessing potential zoonotic diseases at the animal-human interface and comprehending historical factors contributing to spillover events. To bridge policy gaps, comprehensive strategies are proposed that include education, collaborations, specialized task forces, environmental sampling, and the establishment of integrated diagnostic laboratories. These strategies advocate simplicity and unity, breaking down barriers, and placing humanity at the forefront of addressing global health challenges. Such a strategic and mental shift is crucial for constructing a more resilient and equitable world in the face of emerging zoonotic threats.

Rapid loss of maternal immunity and increase in environmentally mediated antibody generation in urban gulls

Monitoring pathogen circulation in wildlife sentinel populations can help to understand and predict the spread of disease at the wildlife-livestock-human interface. Immobile young provide a useful target population for disease surveillance, since they can be easily captured for sampling and their levels of antibodies against infectious agents can provide an index of localized circulation. However, early-life immune responses include both maternally-derived antibodies and antibodies resulting from exposure to pathogens, and disentangling these two processes requires understanding their individual dynamics. We conducted an egg-swapping experiment in an urban-nesting sentinel seabird, the yellow-legged gull, and measured antibody levels against three pathogens of interest (avian influenza virus AIV, Toxoplasma gondii TOX, and infectious bronchitis virus IBV) across various life stages, throughout chick growth, and between nestlings raised by biological or non-biological parents. We found that levels of background circulation differed among pathogens, with AIV antibodies widely present across all life stages, TOX antibodies rarer, and IBV antibodies absent. Antibody titers declined steadily from adult through egg, nestling, and chick stages. For the two circulating pathogens, maternal antibodies declined exponentially after hatching at similar rates, but the rate of linear increase due to environmental exposure was significantly higher in the more prevalent pathogen (AIV). Differences in nestling antibody levels due to parental effects also persisted longer for AIV (25 days, vs. 14 days for TOX). Our results suggest that yellow-legged gulls can be a useful sentinel population of locally transmitted infectious agents, provided that chicks are sampled at ages when environmental exposure outweighs maternal effects.

Accelerometer-based detection of African swine fever infection in wild boar

Infectious wildlife diseases that circulate at the interface with domestic animals pose significant threats worldwide and require early detection and warning. Although animal tracking technologies are used to discern behavioural changes, they are rarely used to monitor wildlife diseases. Common disease-induced behavioural changes include reduced activity and lethargy ('sickness behaviour'). Here, we investigated whether accelerometer sensors could detect the onset of African swine fever (ASF), a viral infection that induces high mortality in suids for which no vaccine is currently available. Taking advantage of an experiment designed to test an oral ASF vaccine, we equipped 12 wild boars with an accelerometer tag and quantified how ASF affects their activity pattern and behavioural fingerprint, using overall dynamic body acceleration. Wild boars showed a daily reduction in activity of 10-20% from the healthy to the viremia phase. Using change point statistics and comparing healthy individuals living in semi-free and free-ranging conditions, we show how the onset of disease-induced sickness can be detected and how such early detection could work in natural settings. Timely detection of infection in animals is crucial for disease surveillance and control, and accelerometer technology on sentinel animals provides a viable complementary tool to existing disease management approaches.

Interrupted Lives: Welfare Considerations in Wildlife Rehabilitation

Each year in the United States, thousands of sick, injured, or displaced wild animals are presented to individuals or organizations who have either a federal or state permit that allows them to care for these animals with the goal of releasing them back to the wild. The purpose of this review is to demonstrate the complexity of considerations rehabilitators and veterinarians face while trying to optimize the welfare of wild animals in need of care and rehabilitation. The process of rehabilitation is inherently stressful for wildlife. Maintaining an animal's welfare during the rehabilitation process-from initial contact and tria+ge to the animal's euthanasia, release, or captive placement-requires deliberate, timely and humane decision making. The welfare of wild animals can be improved by preventing human-related causes of admission, providing resources and support for wildlife rehabilitation (almost all rehabilitation in the United States is privately funded and access to veterinary care is often limited); further developing evidence-based wildlife rehabilitation methods and welfare measures, attracting more veterinary professionals to the field, harmonizing regulatory oversight with standards of care, training, and accountability, and increasing public education.

Clearance and persistence of Escherichia coli in the freshwater mussel Unio mancus

The excessive use of antibiotics has led to the emergence of resistant bacteria, mainly from the Enterobacterales group, with high pathogenic/zoonotic potentials that can lead to problems in public health. The increasing presence in freshwater ecosystems highlights the need to evaluate potential sentinel species as risk indicators for both ecosystem and human health. The freshwater mussels provide several ecosystem services, may represent potential sentinel species due to their ability to filter water and retain both organic and inorganic particles. We tested the capability of U. mancus to retain Escherichia coli as a model bacterial organism. Under experimental conditions, the mussels could clear suspended E. coli, facilitating its rapid elimination from water within the first 24 h after exposure. The species also presented a maximum retention time of 4 days. We also provide allometric equations correlating the filtering capacity with the length and the weight of mussel body parts often used in biometric studies. We provide a first assessment of the potential of the bivalve Unio mancus to act as a sentinel species for the detection of Enterobacterales and demonstrate the ability to act as a water cleaner.

Operationalizing "One Health" as "One Digital Health" Through a Global Framework That Emphasizes Fair and Equitable Sharing of Benefits From the Use of Artificial Intelligence and Related Digital Technologies

The operationalization of One Health (OH) through digitalization is a means to deploy digital technologies (including Artificial Intelligence (AI), big data and related digital technologies) to better capacitate us to deal with growing climate exigency and related threats to human, animal and plant health. With reference to the concept of One Digital Health (ODH), this paper considers how digital capabilities can help to overcome ‘operational brakes’ in OH through new and deeper insights, better predictions, and more targeted or precise preventive strategies and public health countermeasures. However, the data landscape is fragmented and access to certain types of data is increasingly restrictive as individuals, communities and countries seek to assert greater control over data taken from them. This paper proposes for a dedicated global ODH framework—centered on fairness and equity—to be established to promote data-sharing across all the key knowledge domains of OH and to devise data-driven solutions to challenges in the human-animal-ecosystems interface. It first considers the data landscape in relation to: (1) Human and population health; (2) Pathogens; (3) Animal and plant health; and (4) Ecosystems and biodiversity. The complexification from the application of advance genetic sequencing technology is then considered, with focus on current debates over whether certain types of data like digital (genetic) sequencing information (DSI) should remain openly and freely accessible. The proposed ODH framework must augment the existing access and benefit sharing (ABS) framework currently prescribed under the Nagoya Protocol to the Convention on Biological Diversity (CBD) in at least three different ways. First, the ODH framework should apply to all genetic resources and data, including DSI, whether from humans or non-humans. Second, the FAIRER principles should be implemented, with focus on fair and equitable benefit-sharing. Third, the ODH framework should adopt multilateral approaches to data sharing (such as through federated data systems) and to ABS. By operationalizing OH as ODH, we are more likely to be able to protect and restore natural habitats, secure the health and well-being of all living things, and thereby realize the goals set out in the post-2020 Global Biodiversity Framework under the CBD.

Antibiotic Resistance Genes in Lemur Gut and Soil Microbiota Along a Gradient of Anthropogenic Disturbance

The overuse of man-made antibiotics has facilitated the global propagation of antibiotic resistance genes in animals, across natural and anthropogenically disturbed environments. Although antibiotic treatment is the most well-studied route by which resistance genes can develop and spread within host-associated microbiota, resistomes also can be acquired or enriched via more indirect routes, such as via transmission between hosts or via contact with antibiotic-contaminated matter within the environment. Relatively little is known about the impacts of anthropogenic disturbance on reservoirs of resistance genes in wildlife and their environments. We therefore tested for (a) antibiotic resistance genes in primate hosts experiencing different severities and types of anthropogenic disturbance (i.e., non-wildlife animal presence, human presence, direct human contact, and antibiotic treatment), and (b) covariation between host-associated and environmental resistomes. We used shotgun metagenomic sequencing of ring-tailed lemur (Lemur catta) gut resistomes and associated soil resistomes sampled from up to 10 sites: seven in the wilderness of Madagascar and three in captivity in Madagascar or the United States. We found that, compared to wild lemurs, captive lemurs harbored greater abundances of resistance genes, but not necessarily more diverse resistomes. Abundances of resistance genes were positively correlated with our assessments of anthropogenic disturbance, a pattern that was robust across all ten lemur populations. The composition of lemur resistomes was site-specific and the types of resistance genes reflected antibiotic usage in the country of origin, such as vancomycin use in Madagascar. We found support for multiple routes of ARG enrichment (e.g., via human contact, antibiotic treatment, and environmental acquisition) that differed across lemur populations, but could result in similar degrees of enrichment. Soil resistomes varied across natural habitats in Madagascar and, at sites with greater anthropogenic disturbance, lemurs and soil resistomes covaried. As one of the broadest, single-species investigations of wildlife resistomes to date, we show that the transmission and enrichment of antibiotic resistance genes varies across environments, thereby adding to the mounting evidence that the resistance crisis extends outside of traditional clinical settings.

A One Health perspective of the impacts of microplastics on animal, human and environmental health

Microplastics contamination is widespread in the environment leading to the exposure of both humans and other biota. While most studies overemphasize direct toxicity of microplastics, particle concentrations, characteristics and exposure conditions being used in these assays needs to be taken into consideration. For instance, toxicity assays that use concentrations over 100,000 times higher than those expected in the environment have limited practical relevance. Thus, adverse effects on animal and human health of current environmental concentrations are identified as a knowledge gap. Conversely, this does not suggest the lack of any significant effects of microplastics on a global scale. The One Health approach provides a novel perspective focused on the intersection of different areas, namely animal, human, and environmental health. This review provides a One Health transdisciplinary approach to microplastics, addressing indirect effects beyond simple toxicological effects. Microplastics can, theoretically, change the abiotic properties of matrices (e.g., soil permeability) and interfere with essential ecosystem functions affecting ecosystem services (e.g., biogeochemical processes) that can in turn impact human health. The gathered information suggests that more research is needed to clarify direct and indirect effects of microplastics on One Health under environmentally relevant conditions, presenting detailed knowledge gaps.

Lowland tapir exposure to pesticides and metals in the Brazilian Cerrado

Abstract ContextThe Cerrado is a Global Biodiversity Hotspot as well as Brazil’s main frontier for large-scale agriculture and livestock production, making it one of the most threatened biomes in the country. Brazil is one of the biggest consumers of pesticides in the world and allows the use of chemicals that are banned in many other countries due to their adverse health effects in a wide range of species, including humans. AimsThis study aimed to assess pesticide and metal exposure of the lowland tapir – a threatened, large herbivorous mammal – to support future studies of the role of these chemicals in tapir health, survivorship, and population viability. MethodsFoot pad, proboscis, stomach contents, liver, bone, and nail samples were obtained from tapir carcasses found along highways (n=87). (i) Atomic absorption spectrophotometry (AAS) was used to detect metals in bone, nail and liver tissue; (ii) gas chromatography – nitrogen phosphorous detector (GC-NPD) to detect organophosphates in liver and skin; and (iii) high performance liquid chromatography – ultraviolet (HPLC-UV) to detect pyrethroids and carbamates in stomach contents. Key resultsTwo carbamates (aldicarb and carbaryl), three organophosphates (diazinon, malathion, and mevinphos), two pyrethroids (deltamethrin and permethrin), and two toxic metals (cadmium and lead) were detected in different tapir tissue samples, some at concentrations high enough to cause adverse health effects. In 90% of roadkill tapirs that were subjected to a full post-mortem examination (n=25), macroscopic alterations of liver and/or kidney tissue were observed. ConclusionsThis study provides the first report to date of the detection of pesticides and metals in lowland tapirs. ImplicationsSome of the reported pesticide concentrations exceed environmental safety thresholds. Consequently, results from this study raise concerns over potential adverse health effects in tapirs that could lead to population level impacts, thus requiring further investigation.

Examining toxic trace element exposure in American alligators

Toxic trace element exposure occurs through release of the ubiquitous and naturally occurring elements arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg). The unique environmental conditions of the wetland ecosystems along the southeastern Atlantic coast of the United States lead to the accumulation of Hg which is greater than in most other ecosystems in the country. There are also point sources of As, Cd, and Pb in this region. To effectively monitor trace element concentrations, and consequently the potential human exposure, accessible local sentinel species are needed. In this study, concentrations of As, Cd, Pb, Hg and six other trace elements (Al, Ni, Cu, Zn, Se, Mo) were examined in American alligators (Alligator mississippiensis) from seven wetland sites in South Carolina and Florida and assessed for their utility as a sentinel species for human trace element exposure. Alligators were chosen as a potential sentinel as they share a common exposure with the local human population through their aquatic diet, and they are directly consumed commercially and through recreation hunting in this region. Sex was significantly related to the concentration of Zn, Mo, and Al, but not As, Pb, Hg, Cd, Se, or Cu. Site specific differences in element concentrations were observed for As, Pb, Hg, Cd, Se, Zn, and Mo. Size/age was significantly related to the element Hg and Pb concentrations observed. The observed concentration ranges for the four toxic elements, As (6-156 ng/g), Cd (0.3-1.3 ng/g), Pb (3-4872 ng/g), and Hg (39-2765 ng/g), were comparable to those previously reported in diverse human populations. In this region alligators are hunted recreationally and consumed by the local community, making them a vehicle of direct human toxic element exposure. We propose that the similarity in As, Cd, Pb, and Hg concentrations between alligators observed in this study and humans underscores how alligators can serve as a useful sentinel species for toxic element exposure.

Descriptive analysis of ovine mortality in sentinel sheep flocks in Ireland

Background

Studies of sheep mortality or cause-specific mortality, in Ireland or internationally, are relatively scarce but are important in presenting baseline levels and changing trends of endemic disease. This study assessed sheep mortality and cause-specific mortality in 33 sentinel sheep flocks in Ireland.

Methods

Sentinel flocks were requested to submit carcases of all sheep that died to the regional veterinary laboratories (RVLs) of the Department of Agriculture, Food and Marine during a calendar year (2016). Postmortem examinations were performed on 1247 submissions to Athlone, Kilkenny and Sligo RVLs.

Results

The median overall submission rate was 13.8 per cent (range 2.5 per cent–35.8 per cent) per adult female sheep in the flock in January 2016. The median fetal, perinatal, lamb and adult submissions per adult female sheep in the flock in January 2016 were 2.1 per cent (0.0 per cent–15.2 per cent), 3.5 per cent (0.0 per cent–20.0 per cent), 3.0 per cent (0.0 per cent–12.4 per cent) and 2.8 per cent (0.8 per cent–7.1 per cent), respectively. The frequency of detection of categories of postmortem diagnoses in fetuses, perinates, lambs and adults are presented.

Conclusions

Comparisons with existing passive surveillance findings reflect some differences in the relative frequency of detection of certain categories of disease suggesting that sentinel flock surveillance could usefully supplement existing passive animal disease surveillance activities for ovine disease.

Dogs (Canis familiaris) as Sentinels for Human Infectious Disease and Application to Canadian Populations: A Systematic Review

In a world where climate change, vector expansion, human activity, and pathogen dispersal do not respect boundaries, the human⁻animal⁻pathogen interface has become less defined. Consequently, a One Health approach to disease surveillance and control has generated much interest across several disciplines. This systematic review evaluates current global research on the use of domestic dogs as sentinels for human infectious disease, and critically appraises how this may be applied within Canada. Results highlighted a bias in research from high- and middle-income-economy countries, with 35% of the studies describing data from the Latin America/Caribbean region, 25% from North America, and 11% from the European/Central Asia region. Bacteria were the most studied type of infectious agent, followed by protozoa, viruses, helminths, and fungi. Only six out of 142 studies described disease in Canada: four researched a variety of pathogens within Indigenous communities, one researched Borrelia burgdorferi in British Columbia, and one researched arboviruses in Quebec. Results from this review suggest that dogs could provide excellent sentinels for certain infectious-disease pathogens in Canada, yet are currently overlooked. Further research into the use of dog-sentinel surveillance is specifically recommended for California serogroup viruses, Chikungunya virus, West Nile virus, Lyme borreliosis, Rickettsia spp., Ehrlichia spp., and Dirofilaria immitis.

The One Health Concept: 10 Years Old and a Long Road Ahead

Over the past decade, a significant increase in the circulation of infectious agents was observed. With the spread and emergence of epizootics, zoonoses, and epidemics, the risks of pandemics became more and more critical. Human and animal health has also been threatened by antimicrobial resistance, environmental pollution, and the development of multifactorial and chronic diseases. This highlighted the increasing globalization of health risks and the importance of the human-animal-ecosystem interface in the evolution and emergence of pathogens. A better knowledge of causes and consequences of certain human activities, lifestyles, and behaviors in ecosystems is crucial for a rigorous interpretation of disease dynamics and to drive public policies. As a global good, health security must be understood on a global scale and from a global and crosscutting perspective, integrating human health, animal health, plant health, ecosystems health, and biodiversity. In this study, we discuss how crucial it is to consider ecological, evolutionary, and environmental sciences in understanding the emergence and re-emergence of infectious diseases and in facing the challenges of antimicrobial resistance. We also discuss the application of the "One Health" concept to non-communicable chronic diseases linked to exposure to multiple stresses, including toxic stress, and new lifestyles. Finally, we draw up a list of barriers that need removing and the ambitions that we must nurture for the effective application of the "One Health" concept. We conclude that the success of this One Health concept now requires breaking down the interdisciplinary barriers that still separate human and veterinary medicine from ecological, evolutionary, and environmental sciences. The development of integrative approaches should be promoted by linking the study of factors underlying stress responses to their consequences on ecosystem functioning and evolution. This knowledge is required for the development of novel control strategies inspired by environmental mechanisms leading to desired equilibrium and dynamics in healthy ecosystems and must provide in the near future a framework for more integrated operational initiatives.

Animals and Human Health

Human health and animal health are closely intertwined. We share hundreds of diseases with animals, and they are vectors for many diseases that assail humans—but, at the same time, they are essential to many treatments and cures. We discuss in this chapter various aspects of intimate relationship between human and animal health, giving examples of the importance of multidisciplinary studies in understanding these connections and the fundamental aspects of strategies for promoting the health and well-being of both groups.

Mortality related to cold and heat. What do we learn from dairy cattle?

Extreme temperatures are associated with increased mortality among humans. Because similar epidemiologic studies in animals may add to the existing evidence, we investigated the association between ambient temperature and the risk of mortality among dairy cattle. We used data on 87,108 dairy cow deaths in Belgium from 2006 to 2009, and we combined a case-crossover design with distributed lag non-linear models. Province-specific results were combined in a multivariate meta-analysis. Relative to the estimated minimum mortality temperature of 15.4°C (75th percentile), the pooled cumulative relative risks over lag 0-25 days were 1.26 (95% CI: 1.11, 1.42) for extreme cold (1st percentile, -3.5°C), 1.35 (95% CI: 1.19, 1.54) for moderate cold (5th percentile, -0.3°C), 1.09 (95% CI: 1.02, 1.17) for moderate heat (95th percentile, 19.7°C), and 1.26 (95% CI: 1.08; 1.48) for extreme heat (99th percentile, 22.6°C). The temporal pattern of the temperature-mortality association was similar to that observed in humans, i.e. acute effects of heat and delayed and prolonged effects of cold. Seasonal analyses suggested that most of the temperature-related mortality, including cold effects, occurred in the warm season. Our study reinforces the evidence on the plausibility of causal effects in humans.

Reservoir host competence and the role of domestic and commensal hosts in the transmission of Trypanosoma cruzi

We review the epidemiological role of domestic and commensal hosts of Trypanosoma cruzi using a quantitative approach, and compiled >400 reports on their natural infection. We link the theory underlying simple mathematical models of vector-borne parasite transmission to the types of evidence used for reservoir host identification: mean duration of infectious life; host infection and infectiousness; and host-vector contact. The infectiousness of dogs or cats most frequently exceeded that of humans. The host-feeding patterns of major vectors showed wide variability among and within triatomine species related to their opportunistic behavior and variable ecological, biological and social contexts. The evidence shows that dogs, cats, commensal rodents and domesticated guinea pigs are able to maintain T. cruzi in the absence of any other host species. They play key roles as amplifying hosts and sources of T. cruzi in many (peri)domestic transmission cycles covering a broad diversity of ecoregions, ecotopes and triatomine species: no other domestic animal plays that role. Dogs comply with the desirable attributes of natural sentinels and sometimes were a point of entry of sylvatic parasite strains. The controversies on the role of cats and other hosts illustrate the issues that hamper assessing the relative importance of reservoir hosts on the basis of fragmentary evidence. We provide various study cases of how eco-epidemiological and genetic-marker evidence helped to unravel transmission cycles and identify the implicated hosts. Keeping dogs, cats and rodents out of human sleeping quarters and reducing their exposure to triatomine bugs are predicted to strongly reduce transmission risks.

Detecting genomic damages in the frog Dendropsophus minutus: preserved versus perturbed areas

The aim of the study was to use the comet assay (single-cell gel electrophoresis) and micronucleus test to assess the extent of genomic damage in the whole blood of Dendropsophus minutus from agroecosystems with great use of agrochemicals and to compare the results to those obtained from animals living in unpolluted areas. Our results indicated that specimens of D. minutus collected in perturbed areas exhibited higher amounts of DNA damage in blood cells in comparison to animals from areas free of agricultural activities. The average and standard deviation of all comet assay parameters (tail length, percentage of DNA in the tail, and olive tail moment) and micronuclei frequency were significantly higher in specimens collected in perturbed areas than in the animals from preserved areas. Our study showed that animals from perturbed areas, such as agroecosystems, tend to have higher amounts of DNA damage than animals from reference areas. Moreover, we can conclude that D. minutus tadpoles could be included as a model organism in biomonitoring studies.

Early detection of emerging zoonotic diseases with animal morbidity and mortality monitoring

Diseases transmitted between animals and people have made up more than 50% of emerging infectious diseases in humans over the last 60 years and have continued to arise in recent months. Yet, public health and animal disease surveillance programs continue to operate independently. Here, we assessed whether recent emerging zoonotic pathogens (n = 143) are known to cause morbidity or mortality in their animal host and if so, whether they were first detected with an animal morbidity/mortality event. We show that although sick or dead animals are often associated with these pathogens (52%), only 9% were first detected from an animal morbidity or mortality event prior to or concurrent with signs of illness in humans. We propose that an animal morbidity and mortality reporting program will improve detection and should be an essential component of early warning systems for zoonotic diseases. With the use of widespread low-cost technology, such a program could engage both the public and professionals and be easily tested and further incorporated as part of surveillance efforts by public health officials.

Serosurvey for zoonotic viral and bacterial pathogens among slaughtered livestock in Egypt

INTRODUCTION

Zoonotic diseases are an important cause of human morbidity and mortality. Animal populations at locations with high risk of transmission of zoonotic pathogens offer an opportunity to study viral and bacterial pathogens of veterinary and public health concern.

METHODS

Blood samples were collected from domestic and imported livestock slaughtered at the Muneeb abattoir in central Egypt in 2009. Samples were collected from cattle (n=161), buffalo (n=153), sheep (n=174), and camels (n=10). Samples were tested for antibodies against Leptospira spp. by a microscopy agglutination test, Coxiella burnetii by enzyme immunoassay, Brucella spp. by standard tube agglutination, and Rift Valley Fever virus (RVFV), Crimean-Congo hemorrhagic fever virus (CCHFV), sandfly fever Sicilian virus (SFSV), and sandfly fever Naples virus (SFNV) by enzyme-linked immunosorbent assay.

RESULTS

Antibodies against Leptospira spp. were identified in 64 (40%) cattle, 45 (29%) buffalo, 71 (41%) sheep, and five (50%) camels; antibodies against C. burnetii in six (4%) buffalo, 14 (8%) sheep, and seven (70%) camels; and antibodies against Brucella spp. in 12 (8%) cattle, one (1%) buffalo, seven (4%) sheep, and one (10%) camel. Antibodies against RVFV were detected in two (1%) cattle and five (3%) buffalo, and antibodies against CCHFV in one (1%) cow. No antibodies against SFSV or SFNV were detected in any species.

DISCUSSION

RESULTS indicate that livestock have been exposed to a number of pathogens, although care must be taken with interpretation. It is not possible to determine whether antibodies against Leptospira spp. and RVFV in cattle and buffalo are due to prior vaccination or natural exposure. Similarly, antibodies identified in animals less than 6 months of age may be maternal antibodies transferred through colostrum rather than evidence of prior exposure. RESULTS provide baseline evidence to indicate that surveillance within animal populations may be a useful tool to monitor the circulation of pathogens of veterinary and public health concern in Egypt.

Factors associated with the seroprevalence of leishmaniasis in dogs living around Atlantic Forest fragments

Canine visceral leishmaniasis is an important zoonosis in Brazil. However, infection patterns are unknown in some scenarios such as rural settlements around Atlantic Forest fragments. Additionally, controversy remains over risk factors, and most identified patterns of infection in dogs have been found in urban areas. We conducted a cross-sectional epidemiological survey to assess the prevalence of leishmaniasis in dogs through three different serological tests, and interviews with owners to assess features of dogs and households around five Atlantic Forest remnants in southeastern Brazil. We used Generalized Linear Mixed Models and Chi-square tests to detect associations between prevalence and variables that might influence Leishmania infection, and a nearest neighbor dispersion analysis to assess clustering in the spatial distribution of seropositive dogs. Our findings showed an average prevalence of 20% (ranging from 10 to 32%) in dogs. Nearly 40% (ranging from 22 to 55%) of households had at least one seropositive dog. Some individual traits of dogs (height, sterilization, long fur, age class) were found to positively influence the prevalence, while some had negative influence (weight, body score, presence of ectoparasites). Environmental and management features (number of cats in the households, dogs with free-ranging behavior) also entered models as negative associations with seropositivity. Strong and consistent negative (protective) influences of the presence of chickens and pigs in dog seropositivity were detected. Spatial clustering of cases was detected in only one of the five study sites. The results showed that different risk factors than those found in urban areas may drive the prevalence of canine leishmaniasis in farm/forest interfaces, and that humans and wildlife risk infection in these areas. Domestic dog population limitation by gonadectomy, legal restriction of dog numbers per household and owner education are of the greatest importance for the control of visceral leishmaniasis in rural zones near forest fragments.

Mercury, pets' and hair: baseline survey of a priority environmental pollutant using a noninvasive matrix in man's best friend

Pet cats and dogs have been successfully used as indicators of environmental pollution by a great variety of chemicals, including metals. However, information on mercury (a well know priority environmental pollutant) concentrations in household pets tissues and/or organs is scarce. Thus, in the present work we quantified total mercury (Hg(Total)) in blood and hair samples from twenty-six household dogs. The obtained results disclose relatively low levels of total mercury in the surveyed dogs, with values ranging from 0.16 to 12.38 ng g(-1) in blood; and from 24.16 to 826.30 ng g(-1) in hair. Mercury concentrations were independent of gender, age and diet type. A highly significant positive correlation was established between total mercury in blood and hair, validating the latter as a surrogate, non-invasive matrix for mercury exposure evaluation. Additionally, the obtained blood to hair ratio (200) is similar to the one described for humans reinforcing the suitability of dogs as sentinels. Overall, the determination of total mercury levels in dogs' hair samples proved to be a good screening method for the estimation of mercury burden in this species. We propose the quantification of Hg(Total) in hair as a screening method for sentinels like household pets to be performed in routine veterinary visits.

Modeling of wildlife-associated zoonoses: applications and caveats

Wildlife species are identified as an important source of emerging zoonotic disease. Accordingly, public health programs have attempted to expand in scope to include a greater focus on wildlife and its role in zoonotic disease outbreaks. Zoonotic disease transmission dynamics involving wildlife are complex and nonlinear, presenting a number of challenges. First, empirical characterization of wildlife host species and pathogen systems are often lacking, and insight into one system may have little application to another involving the same host species and pathogen. Pathogen transmission characterization is difficult due to the changing nature of population size and density associated with wildlife hosts. Infectious disease itself may influence wildlife population demographics through compensatory responses that may evolve, such as decreased age to reproduction. Furthermore, wildlife reservoir dynamics can be complex, involving various host species and populations that may vary in their contribution to pathogen transmission and persistence over space and time. Mathematical models can provide an important tool to engage these complex systems, and there is an urgent need for increased computational focus on the coupled dynamics that underlie pathogen spillover at the human-wildlife interface. Often, however, scientists conducting empirical studies on emerging zoonotic disease do not have the necessary skill base to choose, develop, and apply models to evaluate these complex systems. How do modeling frameworks differ and what considerations are important when applying modeling tools to the study of zoonotic disease? Using zoonotic disease examples, we provide an overview of several common approaches and general considerations important in the modeling of wildlife-associated zoonoses.

Concurrent 2009 pandemic influenza A (H1N1) virus infection in ferrets and in a community in Pennsylvania

We report a fall 2010 cluster of pandemic influenza A/H1N1 (pH1N1) infections in pet ferrets in Lehigh Valley region of Pennsylvania. The ferrets were associated with one pet shop. The influenza cluster occurred during a period when the existing human surveillance systems had identified little to no pH1N1 in humans in the Lehigh Valley, and there were no routine influenza surveillance systems for exotic pets. The index case was a 2.5-month-old neutered male ferret that was presented to a veterinary clinic with severe influenza-like illness (ILI). In response to laboratory notification of a positive influenza test result, and upon request from the Pennsylvania Department of Health (PADOH), the Pennsylvania Department of Agriculture (PDA) conducted an investigation to identify other ill ferrets and to identify the source and extent of infection. PDA notified the PADOH of the pH1N1 infection in the ferrets, leading to enhanced human surveillance and the detection of pH1N1 human infections in the surrounding community. Five additional ferrets with ILI linked to the pet shop were identified. This simultaneous outbreak of ferret and human pH1N1 demonstrates the important link between animal health and public health and highlights the potential use of veterinary clinics for sentinel surveillance of diseases shared between animals and humans.

Adapting the buccal micronucleus cytome assay for use in wild birds: age and sex affect background frequency in pigeons

Micronucleus (MN) formation has been used extensively as a biomarker of damage from genotoxic exposures. The Buccal MN Cytome (BMCyt) assay provides a noninvasive means of quantifying MN frequency in humans, but it has not been developed for use in wildlife. We adapted the BMCyt assay for use in wild birds, with a focus on feral pigeons (Columba livia) as a potential indicator species. Five of six urban bird species sampled using oral cavity swabs produced sufficient buccal cells for the BMCyt assay. The body size of species sampled ranged almost 100-fold (~60 to 5,000 g), but was a not major factor influencing the number of buccal cells collected. Pigeon cells were stained and scored following published BMCyt assay protocols for humans, but with a modified fixation approach using heat and methanol. Pigeons had the same common nuclear abnormalities reported in human studies, and a similar background MN formation frequency of 0.88 MN/1,000 cells. Adult pigeons had on average a threefold higher rate of MN formation than juveniles, and males had a 1.4- to 2.2-fold higher frequency than females. Domestic and feral pigeons did not differ in overall MN frequency. Our results indicate that the BMCyt assay can be used on wild birds, and could provide a means of assessing environmental genotoxicity in pigeons, a useful indicator species. However, bird age and sex are important factors affecting background MN frequency, and thereby the design of environmental studies.

Mobile phone-based infectious disease surveillance system, Sri Lanka

Because many infectious diseases are emerging in animals in low-income and middle-income countries, surveillance of animal health in these areas may be needed for forecasting disease risks to humans. We present an overview of a mobile phone-based frontline surveillance system developed and implemented in Sri Lanka. Field veterinarians reported animal health information by using mobile phones. Submissions increased steadily over 9 months, with ≈4,000 interactions between field veterinarians and reports on the animal population received by the system. Development of human resources and increased communication between local stakeholders (groups and persons whose actions are affected by emerging infectious diseases and animal health) were instrumental for successful implementation. The primary lesson learned was that mobile phone-based surveillance of animal populations is acceptable and feasible in lower-resource settings. However, any system implementation plan must consider the time needed to garner support for novel surveillance methods among users and stakeholders.

A niche for infectious disease in environmental health: rethinking the toxicological paradigm

OBJECTIVE

In this review we highlight the need to expand the scope of environmental health research, which now focuses largely on the study of toxicants, to incorporate infectious agents. We provide evidence that environmental health research would be strengthened through finding common ground with the tools and approaches of infectious disease research.

DATA SOURCES AND EXTRACTION

We conducted a literature review for examples of interactions between toxic agents and infectious diseases, as well as the role of these interactions as risk factors in classic "environmental" diseases. We investigated existing funding sources and research mandates in the United States from the National Science Foundation and the National Institutes of Health, particularly the National Institute of Environmental Health Sciences.

DATA SYNTHESIS

We adapted the toxicological paradigm to guide reintegration of infectious disease into environmental health research and to identify common ground between these two fields as well as opportunities for improving public health through interdisciplinary research.

CONCLUSIONS

Environmental health encompasses complex disease processes, many of which involve interactions among multiple risk factors, including toxicant exposures, pathogens, and susceptibility. Funding and program mandates for environmental health studies should be expanded to include pathogens in order to capture the true scope of these overlapping risks, thus creating more effective research investments with greater relevance to the complexity of real-world exposures and multifactorial health outcomes. We propose a new model that integrates the toxicology and infectious disease paradigms to facilitate improved collaboration and communication by providing a framework for interdisciplinary research. Pathogens should be part of environmental health research planning and funding allocation, as well as applications such as surveillance and policy development.

Mass culture and characterization of tumor cells from a naturally occurring invertebrate cancer model: applications for human and animal disease and environmental health

On the northeastern coast of the United States and Canada, Mya arenaria, the soft shell clam, develops a diffuse, hemopoetic tumor (a fatal leukemia-like cancer) resulting from inactivation of p53-like family member proteins.These malignant cells provide a model for an unrelated set of human cancer cells that are also characterized by mortalin-based cytoplasmic sequestration of wild-type p53 tumor suppressor protein (mortalin is the mitochondrial Hsp70 protein). Here we describe methods for mass culture and long-term storage of tumor cells from this cancer. These are the first successful efforts at maintaining malignant cells from any marine invertebrate in vitro. Following passage (subculture), these cultures undergo transition from primary cultures to non-immortalized cell lines that continue to proliferate and do not re-differentiate the normal hemocyte phenotype. We also characterize normal clam hemocytes and the pathology of cancerous clam hemocytes in vitro and in vivo using light and electron microscopy, cyto- and immunocytochemistry, molecular biology, and a phagocytosis assay. Our protocols provide biomedical and environmental researchers with ready access to this naturally occurring cancer model. We discuss the clam cancer model regarding (a) human health and disease; (b) animal health, disease, and aquaculture; (c) environmental health monitoring; and (d) future research directions.

From "us vs. them" to "shared risk": can animals help link environmental factors to human health?

Linking human health risk to environmental factors can be a challenge for clinicians, public health departments, and environmental health researchers. While it is possible that nonhuman animal species could help identify and mitigate such linkages, the fields of animal and human health remain far apart, and the prevailing human health attitude toward disease events in animals is an "us vs. them" paradigm that considers the degree of threat that animals themselves pose to humans. An alternative would be the development of the concepts of animals as models for environmentally induced disease, as well as potential "sentinels" providing early warning of both noninfectious and infectious hazards in the environment. For such concepts to truly develop, critical knowledge gaps need to be addressed using a "shared risk" paradigm based on the comparative biology of environment-host interactions in different species.

Effects of climate change on Arctic marine mammal health

The lack of integrated long-term data on health, diseases, and toxicant effects in Arctic marine mammals severely limits our ability to predict the effects of climate change on marine mammal health. The overall health of an individual animal is the result of complex interactions among immune status, body condition, pathogens and their pathogenicity, toxicant exposure, and the various environmental conditions that interact with these factors. Climate change could affect these interactions in several ways. There may be direct effects of loss of the sea ice habitat, elevations of water and air temperature, and increased occurrence of severe weather. Some of the indirect effects of climate change on animal health will likely include alterations in pathogen transmission due to a variety of factors, effects on body condition due to shifts in the prey base/food web, changes in toxicant exposures, and factors associated with increased human habitation in the Arctic (e.g., chemical and pathogen pollution in the runoff due to human and domestic-animal wastes and chemicals and increased ship traffic with the attendant increased risks of ship strike, oil spills, ballast pollution, and possibly acoustic injury). The extent to which climate change will impact marine mammal health will also vary among species, with some species more sensitive to these factors than others. Baseline data on marine mammal health parameters along with matched data on the population and climate change trends are needed to document these changes.

A framework for evaluating animals as sentinels for infectious disease surveillance

The dynamics of infectious diseases are highly variable. Host ranges, host responses to pathogens and the relationships between hosts are heterogeneous. Here, we argue that the use of animal sentinels has the potential to use this variation and enable the exploitation of a wide range of pathogen hosts for surveillance purposes. Animal sentinels may be used to address many surveillance questions, but they may currently be underused as a surveillance tool and there is a need for improved interdisciplinary collaboration and communication in order to fully explore the potential of animal sentinels. In different contexts, different animal hosts will themselves vary in their capacity to provide useful information. We describe a conceptual framework within which the characteristics of different host populations and their potential value as sentinels can be evaluated in a broad range of settings.

Sentinel surveillance systems with special focus on vector-borne diseases

In the past few decades, vector-borne diseases have been spreading into countries previously free of these agents. It is necessary for a surveillance method to be tailored to the biology of these agents in order to detect their incursion. Using a sentinel herd system, it is possible to target high-risk areas where occurrence is most probably due to vector presence. Since the 1970s, diseases such as Akabane, vesicular stomatitis and Bluetongue disease have successfully been monitored using cattle herds as sentinels in many countries such as Saudi Arabia, Australia, China, Indonesia, Sultanate of Oman and most recently in countries in Western Europe. This paper reviews the strengths and weaknesses of sentinel herd surveillance systems in general. In order to determine their efficacy, the following criteria were found to be essential: the choice of sentinel locations, sentinel animal, seasonality of sampling and diagnostic testing methods. We conclude that due to its ability to focus on a specific disease, sentinel herd systems have been successful in the early detection of the spread of a targeted agent. This review is used as a basis for recommendations for the development of future sentinel herd systems.