The significant but understudied impact of pathogen transmission from humans to animals

Flexible grouping patterns in a western and eastern chimpanzee community

Primate social organizations, or grouping patterns, vary significantly across species. Behavioral strategies that allow for flexibility in grouping patterns offer a means to reduce the costs of group living. Chimpanzees (Pan troglodytes) have a fission-fusion social system in which temporary subgroups ("parties") change in composition because of local socio-ecological conditions. Notably, western chimpanzees (P. t. verus) are described as showing a higher degree of bisexual bonding and association than eastern chimpanzees, and eastern female chimpanzees (P. t. schweinfurthii) are thought to be more solitary than western female chimpanzees. However, reported comparisons in sociality currently depend on a small number of study groups, particularly in western chimpanzees, and variation in methods. The inclusion of additional communities and direct comparison using the same methods are essential to assess whether reported subspecies differences in sociality hold in this behaviorally heterogeneous species. We explored whether sociality differs between two communities of chimpanzees using the same motion-triggered camera technology and definitions of social measures. We compare party size and composition (party type, sex ratio) between the western Gahtoy community in the Nimba Mountains (Guinea) and the eastern Waibira community in the Budongo Forest (Uganda). Once potential competition for resources such as food and mating opportunities were controlled for, subspecies did not substantially influence the number of individuals in a party. We found a higher sex-ratio, indicating more males in a party, in Waibira; this pattern was driven by a greater likelihood in Gahtoy to be in all-female parties. This finding is the opposite of what was expected for eastern chimpanzees, where female-only parties are predicted to be more common. Our results highlight the flexibility in chimpanzee sociality, and caution against subspecies level generalizations.

Phylogenomic analysis supports Mycobacterium tuberculosis transmission between humans and elephants

Introduction

Tuberculosis is an infectious disease caused by a group of acid-fast bacilli known as Mycobacterium tuberculosis complex (MTC), which has a major impact on humans. Transmission of MTC across the human-animal interface has been demonstrated by several studies. However, the reverse zoonotic transmission from humans to animals (zooanthroponosis) has often been neglected.

Methods

In this study, we used Nanopore MinION and Illumina MiSeq approaches to sequence the whole genome of M. tuberculosis strains isolated from two deceased Asian elephants (Elephas maximus) and one human in Chitwan, Nepal. The evolutionary relationships and drug resistance capacity of these strains were assessed using the whole genome data generated by the stand-alone tool Tb-Profiler. Phylogenomic trees were also constructed using a non-synonymous SNP alignment of 2,596 bp, including 94 whole genome sequences representative of the previously described M. tuberculosis lineages from elephants worldwide (lineages 1 and 4) and from humans in Nepal (lineages 1, 2 and 3).

Results and Discussion

The new genomes achieved an average coverage of 99.6%, with an average depth of 55.67x. These M. tuberculosis strains belong to lineage 1 (elephant DG), lineage 2 (elephant PK) and lineage 4 (human), and none of them were found to have drug-resistant variants. The elephant-derived isolates were evolutionarily closely related to human-derived isolates previously described in Nepal, both in lineages 1 and 2, providing additional support for zooanthroponosis or bidirectional transmission between humans and elephants. The human-derived isolate clustered together with other published human isolates from Argentina, Russia and the United Kingdom in the lineage 4 clade. This complex multi-pathogen, multi-host system is challenging and highlights the need for a One Health approach to tuberculosis prevention and control at human-animal interface, particularly in regions where human tuberculosis is highly endemic.

Staphylococcus aureus Host Spectrum Correlates with Methicillin Resistance in a Multi-Species Ecosystem

Although antibiotic resistance is a major issue for both human and animal health, very few studies have investigated the role of the bacterial host spectrum in its dissemination within natural ecosystems. Here, we assessed the prevalence of methicillin resistance among Staphylococcus aureus (MRSA) isolates from humans, non-human primates (NHPs), micromammals and bats in a primatology center located in southeast Gabon, and evaluated the plausibility of four main predictions regarding the acquisition of antibiotic resistance in this ecosystem. MRSA strain prevalence was much higher in exposed species (i.e., humans and NHPs which receive antibiotic treatment) than in unexposed species (micromammals and bats), and in NHP species living in enclosures than those in captivity-supporting the assumption that antibiotic pressure is a risk factor in the acquisition of MRSA that is reinforced by the irregularity of drug treatment. In the two unexposed groups of species, resistance prevalence was high in the generalist strains that infect humans or NHPs, supporting the hypothesis that MRSA strains diffuse to wild species through interspecific transmission of a generalist strain. Strikingly, the generalist strains that were not found in humans showed a higher proportion of MRSA strains than specialist strains, suggesting that generalist strains present a greater potential for the acquisition of antibiotic resistance than specialist strains. The host spectrum is thus a major component of the issue of antibiotic resistance in ecosystems where humans apply strong antibiotic pressure.

A Review on Zoonotic Pathogens Associated with Non-Human Primates: Understanding the Potential Threats to Humans

Non-human primates (NHP) share a close relationship with humans due to a genetic homology of 75-98.5%. NHP and humans have highly similar tissue structures, immunity, physiology, and metabolism and thus often can act as hosts to the same pathogens. Agriculture, meat consumption habits, tourism development, religious beliefs, and biological research have led to more extensive and frequent contact between NHPs and humans. Deadly viruses, such as rabies virus, herpes B virus, Marburg virus, Ebola virus, human immunodeficiency virus, and monkeypox virus can be transferred from NHP to humans. Similarly, herpes simplex virus, influenza virus, and yellow fever virus can be transmitted to NHP from humans. Infectious pathogens, including viruses, bacteria, and parasites, can affect the health of both primates and humans. A vast number of NHP-carrying pathogens exhibit a risk of transmission to humans. Therefore, zoonotic infectious diseases should be evaluated in future research. This article reviews the research evidence, diagnostic methods, prevention, and treatment measures that may be useful in limiting the spread of several common viral pathogens via NHP and providing ideas for preventing zoonotic diseases with epidemic potential.

Potential SARS-CoV-2 Susceptibility of Cetaceans Stranded along the Italian Coastline

Due to marine mammals' demonstrated susceptibility to SARS-CoV-2, based upon the homology level of their angiotensin-converting enzyme 2 (ACE2) viral receptor with the human one, alongside the global SARS-CoV-2 occurrence and fecal contamination of the river and marine ecosystems, SARS-CoV-2 infection may be plausibly expected to occur also in cetaceans, with special emphasis on inshore species like bottlenose dolphins (Tursiops truncatus). Moreover, based on immune and inflammatory responses to SARS-CoV-2 infection in humans, macrophages could also play an important role in antiviral defense mechanisms. In order to provide a more in-depth insight into SARS-CoV-2 susceptibility in marine mammals, we evaluated the presence of SARS-CoV-2 and the expression of ACE2 and the pan-macrophage marker CD68. Aliquots of tissue samples, belonging to cetaceans stranded along the Italian coastline during 2020-2021, were collected for SARS-CoV-2 analysis by real-time PCR (RT-PCRT) (N = 43) and Immunohistochemistry (IHC) (N = 59); thirty-two aliquots of pulmonary tissue sample (N = 17 Tursiops truncatus, N = 15 Stenella coeruleoalba) available at the Mediterranean Marine Mammal Tissue Bank (MMMTB) of the University of Padua (Legnaro, Padua, Italy) were analyzed to investigate ACE2 expression by IHC. In addition, ACE2 and CD68 were also investigated by Double-Labeling Immunofluorescence (IF) Confocal Laser Microscopy. No SARS-CoV-2 positivity was found in samples analyzed for the survey while ACE2 protein was detected in the lower respiratory tract albeit heterogeneously for age, gender/sex, and species, suggesting that ACE2 expression can vary between different lung regions and among individuals. Finally, double IF analysis showed elevated colocalization of ACE2 and CD68 in macrophages only when an evident inflammatory reaction was present, such as in human SARS-CoV-2 infection.

Between forest and croplands: Nocturnal behavior in wild chimpanzees of Sebitoli, Kibale National Park, Uganda

Some animal species have been presumed to be purely diurnal. Yet, they show flexibility in their activity rhythm, and can occasionally be active at night. Recently, it has been suggested that chimpanzees may rarely engage in nocturnal activities in savannah forests, in contrast to the frequent nocturnal feeding of crops observed at Sebitoli, Kibale National Park, Uganda. Here we thus aimed to explore the factors that might trigger such intense nocturnal activity (e.g. harsher weather conditions during daytime, low wild food availability or higher diurnal foraging risk) in this area. We used camera-traps set over 18 km2 operating for 15 months. We report activities and group composition from records obtained either within the forest or at the forest interface with maize fields, the unique crop consumed. Maize is an attractive and accessible food source, although actively guarded by farmers, particularly during daytime. Out of the 19 156 clips collected, 1808 recorded chimpanzees. Of these, night recordings accounted for 3.3% of forest location clips, compared to 41.8% in the maize fields. Most nocturnal clips were obtained after hot days, and most often during maize season for field clips. At night within the forest, chimpanzees were travelling around twilight hours, while when at the border of the fields they were foraging on crops mostly after twilight and in smaller parties. These results suggest that chimpanzees change their activity rhythm to access cultivated resources when human presence and surveillance is lower. This survey provides evidence of behavioral plasticity in chimpanzees in response to neighboring human farming activities, and emphasizes the urgent need to work with local communities to mitigate human-wildlife conflict related to crop-feeding.

Risk of human-to-wildlife transmission of SARS-CoV-2

It has been a long time since the world has experienced a pandemic with such a rapid devastating impact as the current COVID-19 pandemic. The causative agent, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is unusual in that it appears capable of infecting many different mammal species. As a significant proportion of people worldwide are infected with SARS-CoV-2 and may spread the infection unknowingly before symptoms occur or without any symptoms ever occurring, there is a non-negligible risk of humans spreading SARS-CoV-2 to wildlife, in particular to wild non-human mammals. Because of SARS-CoV-2's apparent evolutionary origins in bats and reports of humans transmitting the virus to pets and zoo animals, regulations for the prevention of human-to-animal transmission have so far focused mostly on these animal groups. We summarise recent studies and reports that show that a wide range of distantly related mammals are likely to be susceptible to SARS-CoV-2, and that susceptibility or resistance to the virus is, in general, not predictable, or only predictable to some extent, from phylogenetic proximity to known susceptible or resistant hosts. In the absence of solid evidence on the susceptibility and resistance to SARS-CoV-2 for each of the >6500 mammal species, we argue that sanitary precautions should be taken by humans interacting with any other mammal species in the wild. Preventing human-to-wildlife SARS-CoV-2 transmission is important to protect these animals (some of which are classed as threatened) from disease, but also to avoid establishment of novel SARS-CoV-2 reservoirs in wild mammals. The risk of repeated re-infection of humans from such a wildlife reservoir could severely hamper SARS-CoV-2 control efforts. Activities during which direct or indirect interaction with wild mammals may occur include wildlife research, conservation activities, forestry work, pest control, management of feral populations, ecological consultancy work, management of protected areas and natural environments, wildlife tourism and wildlife rehabilitation in animal shelters. During such activities, we recommend sanitary precautions, such as physical distancing, wearing face masks and gloves, and frequent decontamination, which are very similar to regulations currently imposed to prevent transmission among humans. We further recommend active surveillance of domestic and feral animals that could act as SARS-CoV-2 intermediate hosts between humans and wild mammals.

Opportunities for respiratory disease transmission from people to chimpanzees at an East African tourism site

Respiratory illnesses, including COVID-19, present a serious threat to endangered wild chimpanzee (Pan troglodytes) populations. In some parts of sub-Saharan Africa, chimpanzee tracking is a popular tourism activity, offering visitors a chance to view apes in their natural habitats. Chimpanzee tourism is an important source of revenue and thus benefits conservation; however, chimpanzee tracking may also increase the risk of disease transmission from people to chimpanzees directly (e.g., via aerosol transmission) or indirectly (e.g., through the environment or via fomites). This study assessed how tourist behaviors might facilitate respiratory disease transmission at a chimpanzee tracking site in Kibale National Park, Uganda. We observed tourists, guides, and student interns from the time they entered the forest to view the chimpanzees until they left the forest and noted behaviors related to disease transmission. Common behaviors included coughing, sneezing, and urinating, which respectively occurred during 88.1%, 65.4%, and 36.6% of excursions. Per excursion, individuals touched their faces an average of 125.84 ± 34.45 times and touched large tree trunks or branches (which chimpanzees might subsequently touch) an average of 230.14 ± 108.66 times. These results show that many pathways exist by which pathogens might move from humans to chimpanzees in the context of tourism. Guidelines for minimizing the risk of such transmission should consider tourist behavior and the full range of modes by which pathogen transmission might occur between tourists and chimpanzees.

Assessing the SARS-CoV-2 threat to wildlife: Potential risk to a broad range of mammals

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can infect animals, however, the whole range of potential hosts is still unknown. This work makes an assessment of wildlife susceptibility to SARS-CoV-2 by analyzing the similarities of Angiotensin Converting Enzyme 2 (ACE2) and Transmembrane Protease, Serine 2 (TMPRSS2)-both recognized as receptors and protease for coronavirus spike protein-and the genetic variation of the viral protein spike in the recognition sites. The sequences from different mammals, birds, reptiles, and amphibians, and the sequence from SARS-CoV-2 S protein were obtained from the GenBank. Comparisons of aligned sequences were made by selecting amino acids residues of ACE2, TMPRSS2 and S protein; phylogenetic trees were reconstructed using the same sequences. The species susceptibility was ranked by substituting the values of amino acid residues for both proteins. Our results ranked primates at the top, but surprisingly, just below are carnivores, cetaceans and wild rodents, showing a relatively high potential risk, as opposed to lab rodents that are typically mammals at lower risk. Most of the sequences from birds, reptiles and amphibians occupied the lowest ranges in the analyses. Models and phylogenetic trees outputs showed the species that are more prone to getting infected with SARS-CoV-2. Interestingly, during this short pandemic period, a high haplotypic variation was observed in the RBD of the viral S protein, suggesting new risks for other hosts. Our findings are consistent with other published results reporting laboratory and natural infections in different species. Finally, urgent measures of wildlife monitoring are needed regarding SARS-CoV-2, as well as measures for avoiding or limiting human contact with wildlife, and precautionary measures to protect wildlife workers and researchers; monitoring disposal of waste and sewage than can potentially affect the environment, and designing protocols for dealing with the outbreak.

Possibility for reverse zoonotic transmission of SARS-CoV-2 to free-ranging wildlife: A case study of bats

The COVID-19 pandemic highlights the substantial public health, economic, and societal consequences of virus spillover from a wildlife reservoir. Widespread human transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) also presents a new set of challenges when considering viral spillover from people to naïve wildlife and other animal populations. The establishment of new wildlife reservoirs for SARS-CoV-2 would further complicate public health control measures and could lead to wildlife health and conservation impacts. Given the likely bat origin of SARS-CoV-2 and related beta-coronaviruses (β-CoVs), free-ranging bats are a key group of concern for spillover from humans back to wildlife. Here, we review the diversity and natural host range of β-CoVs in bats and examine the risk of humans inadvertently infecting free-ranging bats with SARS-CoV-2. Our review of the global distribution and host range of β-CoV evolutionary lineages suggests that 40+ species of temperate-zone North American bats could be immunologically naïve and susceptible to infection by SARS-CoV-2. We highlight an urgent need to proactively connect the wellbeing of human and wildlife health during the current pandemic and to implement new tools to continue wildlife research while avoiding potentially severe health and conservation impacts of SARS-CoV-2 "spilling back" into free-ranging bat populations.

Staphylococcus aureus Epidemiology in Wildlife: A Systematic Review

Staphylococcus aureus is a common bacterial colonizer of humans and a variety of animal species. Many strains have zoonotic potential, moving between humans and animals, including livestock, pets, and wildlife. We examined publications reporting on S. aureus presence in a variety of wildlife species in order to more cohesively review distribution of strains and antibiotic resistance in wildlife. Fifty-one studies were included in the final qualitative synthesis. The most common types documented included ST398, ST425, ST1, ST133, ST130, and ST15. A mix of methicillin-resistant and methicillin-susceptible strains were noted. A number of molecular types were identified that were likely to be found in wildlife species, including those that are commonly found in humans or other animal species (including livestock). Additional research should include follow-up in geographic areas that are under-sampled in this study, which is dominated by European studies.

Molecular characterization of group A rotavirus from rhesus macaques (Macaca mulatta) at human-wildlife interfaces in Bangladesh

Group A rotavirus (RVA) is an important cause of diarrhoea in people, especially children, and animals globally. Due to the segmented nature of the RVA genome, animal RVA strains have the potential to adapt to the human host through reassortment with other co-infecting human viruses. Macaques share food and habitat with people, resulting in close interaction between these two species. This study aimed to detect and characterize RVA in rhesus macaques (Macaca mulatta) in Bangladesh. Faecal samples (N = 454) were collected from apparently healthy rhesus macaques from nine different sites in Bangladesh between February and March 2013. The samples were tested by one-step, real-time, reverse transcriptase-polymerase chain reaction (PCR). Four percent of samples (n = 20; 95% CI 2.7%-6.7%) were positive for RVA. RVA positive samples were further characterized by nucleotide sequence analysis of two structural protein gene fragments, VP4 (P genotype) and VP7 (G genotype). G3, G10, P[3] and P[15] genotypes were identified and were associated as G3P[3], G3P[15] and G10P[15]. The phylogenetic relationship between macaque RVA strains from this study and previously reported human strains indicates possible transmission between humans and macaques in Bangladesh. To our knowledge, this is the first report of detection and characterization of rotaviruses in rhesus macaques in Bangladesh. These data will not only aid in identifying viral sharing between macaques, human and other animals, but will also improve the development of mitigation measures for the prevention of future rotavirus outbreaks.

Infectious Disease Risk Across the Growing Human-Non Human Primate Interface: A Review of the Evidence

Most of the human pandemics reported to date can be classified as zoonoses. Among these, there is a long history of infectious diseases that have spread from non-human primates (NHP) to humans. For millennia, indigenous groups that depend on wildlife for their survival were exposed to the risk of NHP pathogens' transmission through animal hunting and wild meat consumption. Usually, exposure is of no consequence or is limited to mild infections. In rare situations, it can be more severe or even become a real public health concern. Since the emergence of acquired immune deficiency syndrome (AIDS), nobody can ignore that an emerging infectious diseases (EID) might spread from NHP into the human population. In large parts of Central Africa and Asia, wildlife remains the primary source of meat and income for millions of people living in rural areas. However, in the past few decades the risk of exposure to an NHP pathogen has taken on a new dimension. Unprecedented breaking down of natural barriers between NHP and humans has increased exposure to health risks for a much larger population, including people living in urban areas. There are several reasons for this: (i) due to road development and massive destruction of ecosystems for agricultural needs, wildlife and humans come into contact more frequently; (ii) due to ecological awareness, many long distance travelers are in search of wildlife discovery, with a particular fascination for African great apes; (iii) due to the attraction for ancient temples and mystical practices, others travelers visit Asian places colonized by NHP. In each case, there is a risk of pathogen transmission through a bite or another route of infection. Beside the individual risk of contracting a pathogen, there is also the possibility of starting a new pandemic. This article reviews the known cases of NHP pathogens' transmission to humans whether they are hunters, travelers, ecotourists, veterinarians, or scientists working on NHP. Although pathogen transmission is supposed to be a rare outcome, Rabies virus, Herpes B virus, Monkeypox virus, Ebola virus, or Yellow fever virus infections are of greater concern and require quick countermeasures from public health professionals.

Facial dysplasia in wild forest olive baboons (Papio anubis) in Sebitoli, Kibale National Park, Uganda: Use of camera traps to detect health defects

BACKGROUND

Primate populations are in decline, mainly affected by agriculture leading to habitat loss, fragmentation but also chemical pollution. Kibale National Park (Uganda), Sebitoli forest, surrounded by tea and crop fields, is the home range of chimpanzees presenting congenital facial dysplasia. This study aimed to identify to what extent the same phenotypical features are observed in baboons (Papio anubis) of this area.

METHODS

A total of 25 390 clips recorded by 14 camera traps between January 2017 and April 2018 were analyzed.

RESULTS

We identified 30 immature and adult baboons of both sexes with nose and lip deformities. They were more frequently observed in the northwestern part of the area.

CONCLUSIONS

A possible effect of pesticides used in crops at the border of their habitat is suspected to alter the embryonic development. This study emphasizes the importance of non-invasive methods to detect health problems in wild primates that can act as sentinels for human health.

Optimizing syndromic health surveillance in free ranging great apes: the case of Gombe National Park

1. Syndromic surveillance is an incipient approach to early wildlife disease detection. Consequently, systematic assessments are needed for methodology validation in wildlife populations. 2. We evaluated the sensitivity of a syndromic surveillance protocol for respiratory disease detection among chimpanzees in Gombe National Park, Tanzania. Empirical health, behavioural and demographic data were integrated with an agent-based, network model to simulate disease transmission and surveillance. 3. Surveillance sensitivity was estimated as 66% (95% Confidence Interval: 63.1, 68.8%) and 59.5% (95% Confidence Interval: 56.5%, 62.4%) for two monitoring methods (weekly count and prevalence thresholds, respectively), but differences among calendar quarters in outbreak size and surveillance sensitivity suggest seasonal effects. 4. We determined that a weekly detection threshold of ≥2 chimpanzees with clinical respiratory disease leading to outbreak response protocols (enhanced observation and biological sampling) is an optimal algorithm for outbreak detection in this population. 5. Synthesis and applications. This is the first quantitative assessment of syndromic surveillance in wildlife, providing a model approach to detecting disease emergence. Coupling syndromic surveillance with targeted diagnostic sampling in the midst of suspected outbreaks will provide a powerful system for detecting disease transmission and understanding population impacts.

Food for contagion: synthesis and future directions for studying host-parasite responses to resource shifts in anthropogenic environments

Human-provided resource subsidies for wildlife are diverse, common and have profound consequences for wildlife-pathogen interactions, as demonstrated by papers in this themed issue spanning empirical, theoretical and management perspectives from a range of study systems. Contributions cut across scales of organization, from the within-host dynamics of immune function, to population-level impacts on parasite transmission, to landscape- and regional-scale patterns of infection. In this concluding paper, we identify common threads and key findings from author contributions, including the consequences of resource subsidies for (i) host immunity; (ii) animal aggregation and contact rates; (iii) host movement and landscape-level infection patterns; and (iv) interspecific contacts and cross-species transmission. Exciting avenues for future work include studies that integrate mechanistic modelling and empirical approaches to better explore cross-scale processes, and experimental manipulations of food resources to quantify host and pathogen responses. Work is also needed to examine evolutionary responses to provisioning, and ask how diet-altered changes to the host microbiome influence infection processes. Given the massive public health and conservation implications of anthropogenic resource shifts, we end by underscoring the need for practical recommendations to manage supplemental feeding practices, limit human-wildlife conflicts over shared food resources and reduce cross-species transmission risks, including to humans.This article is part of the theme issue 'Anthropogenic resource subsidies and host-parasite dynamics in wildlife'.

An epidemiologic study of antimicrobial resistance of Staphylococcus species isolated from equine samples submitted to a diagnostic laboratory

Background

Antimicrobial resistance limits traditional treatment options and increases costs. It is therefore important to estimate the magnitude of the problem so as to provide empirical data to guide control efforts. The aim of this study was to investigate the burden and patterns of antimicrobial resistance (AMR) among equine Staphylococcus samples submitted to the University of Kentucky Veterinary Diagnostic Laboratory (UKVDL) from 1993 to 2009. Retrospective data of 1711 equine Staphylococcus samples submitted to the UKVDL during the time period 1993 to 2009 were included in the study. Antimicrobial susceptibility testing, that included 16 drugs, were performed using cultures followed by the Kirby-Bauer disk diffusion susceptibility test. The proportion of resistant isolates by animal breed, species of organism, sample source, and time period were computed. Chi-square and Cochran-Armitage trend tests were used to identify significant associations and temporal trends, respectively. Logistic regression models were used to investigate predictors of AMR and multidrug resistance (MDR).

Results

A total of 66.3% of the isolates were resistant to at least one antimicrobial, most of which were Staphylococcus aureus (77.1%), while 25.0% were MDR. The highest level of resistance was to penicillins (52.9%). Among drug classes, isolates had the highest rate of AMR to at least one type of β-lactams (49.2%), followed by aminoglycosides (30.2%). Significant (p < 0.05) associations were observed between odds of AMR and horse breed, species of organism and year. Similarly, significant (p < 0.05) associations were identified between odds of MDR and breed and age. While some isolates had resistance to up to 12 antimicrobials, AMR profiles featuring single antimicrobials such as penicillin were more common than those with multiple antimicrobials.

Conclusion

Demographic factors were significant predictors of AMR and MDR. The fact that some isolates had resistance to up to 12 of the 16 antimicrobials assessed is quite concerning. To address the high levels of AMR and MDR observed in this study, future studies will need to focus on antimicrobial prescription practices and education of both practitioners and animal owners on judicious use of antimicrobials to slow down the development of resistance.

Tuberculosis serosurveillance and management practices of captive African elephants (Loxodonta africana) in the Kavango-Zambezi Transfrontier Conservation Area

Transfrontier conservation areas represent an international effort to encourage conservation and sustainable development. Their success faces a number of challenges, including disease management in wildlife, livestock and humans. Tuberculosis (TB) affects humans and a multitude of non-human animal species and is of particular concern in sub-Saharan Africa. The Kavango-Zambezi Transfrontier Conservation Area encompasses five countries, including Zimbabwe, and is home to the largest contiguous population of free-ranging elephants in Africa. Elephants are known to be susceptible to TB; thus, understanding TB status, exposure and transmission risks to and from elephants in this area is of interest for both conservation and human health. To assess risk factors for TB seroprevalence, a questionnaire was used to collect data regarding elephant management at four ecotourism facilities offering elephant-back tourist rides in the Victoria Falls area of Zimbabwe. Thirty-five working African elephants were screened for Mycobacterium tuberculosis complex antibodies using the ElephantTB Stat-Pak and the DPP VetTB Assay for elephants. Six of 35 elephants (17.1%) were seropositive. The risk factor most important for seropositive status was time in captivity. This is the first study to assess TB seroprevalence and risk factors in working African elephants in their home range. Our findings will provide a foundation to develop guidelines to protect the health of captive and free-ranging elephants in the southern African context, as well as elephant handlers through simple interventions. Minimizing exposure through shared feed with other wildlife, routine TB testing of elephant handlers and regular serological screening of elephants are recommended as preventive measures.

TRYPANOSOMA CRUZI AND LEISHMANIA SP. INFECTION IN WILDLIFE FROM URBAN RAINFOREST FRAGMENTS IN NORTHEAST BRAZIL

:  Trypanosoma cruzi and Leishmania sp. are important protozoan parasites for humans and animals in the Americas, causing Chagas disease and cutaneous or visceral leishmaniasis, respectively. These vector-borne diseases affect permanent and transient populations in developing tropical countries that exhibit favorable conditions for the perpetuation of the parasite cycle. Our objective was to investigate the occurrence of infection with these parasites in wild animals from urban rainforest fragments in the city of Salvador, the largest city in the northeast region of Brazil. Sixty-five wild animals were captured, clinically examined, and sampled for parasite detection by PCR and culture. Ten different mammalian genera were identified, being 58% (38/65) marsupials. The prevalence of T. cruzi and Leishmania sp. infections was 13% and 43%, respectively. Both parasites were detected by PCR in 11% (7/65), three of which were also double infected as determined by culture. Among the 28 animals found infected with at least one parasite (43%, 28/65), 68% (19/28) were marsupials, two specimens were Callithrix sp. (7%), and one was Trinomys sp. (3%). Most infected animals (89%) had no clinical signs of disease. We found that healthy free-living animals from urban rainforest fragments harbored pathogenic trypanosomatids and should be included in epidemiology studies of diseases in big cities in tropical countries, as these cities grow and engulf rainforest remnants.

Host and viral traits predict zoonotic spillover from mammals

The majority of human emerging infectious diseases are zoonotic, with viruses that originate in wild mammals of particular concern (for example, HIV, Ebola and SARS). Understanding patterns of viral diversity in wildlife and determinants of successful cross-species transmission, or spillover, are therefore key goals for pandemic surveillance programs. However, few analytical tools exist to identify which host species are likely to harbour the next human virus, or which viruses can cross species boundaries. Here we conduct a comprehensive analysis of mammalian host-virus relationships and show that both the total number of viruses that infect a given species and the proportion likely to be zoonotic are predictable. After controlling for research effort, the proportion of zoonotic viruses per species is predicted by phylogenetic relatedness to humans, host taxonomy and human population within a species range-which may reflect human-wildlife contact. We demonstrate that bats harbour a significantly higher proportion of zoonotic viruses than all other mammalian orders. We also identify the taxa and geographic regions with the largest estimated number of 'missing viruses' and 'missing zoonoses' and therefore of highest value for future surveillance. We then show that phylogenetic host breadth and other viral traits are significant predictors of zoonotic potential, providing a novel framework to assess if a newly discovered mammalian virus could infect people.

Host and viral traits predict zoonotic spillover from mammals

Analysis of a comprehensive database of mammalian host–virus relationships reveals that both the total number of viruses that infect a given species and the proportion likely to be zoonotic are predictable and that this enables identification of mammalian species and geographic locations where novel zoonoses are likely to be found.

Zoonotic viruses, many originating in wild mammals, pose a serious threat to global public health. Peter Daszak and colleagues create a comprehensive database of mammalian host–virus relationships, which they analyse to determine patterns of virus and zoonotic virus distribution in mammals. They identify various factors that influence the number and diversity of viruses that infect a given species as well as factors that predict the proportion of zoonotic viruses per species. In doing so, they identify mammalian species and geographic locations where novel zoonoses are likely to be found.

The majority of human emerging infectious diseases are zoonotic, with viruses that originate in wild mammals of particular concern (for example, HIV, Ebola and SARS)^1,2,3. Understanding patterns of viral diversity in wildlife and determinants of successful cross-species transmission, or spillover, are therefore key goals for pandemic surveillance programs⁴. However, few analytical tools exist to identify which host species are likely to harbour the next human virus, or which viruses can cross species boundaries^5,6,7. Here we conduct a comprehensive analysis of mammalian host–virus relationships and show that both the total number of viruses that infect a given species and the proportion likely to be zoonotic are predictable. After controlling for research effort, the proportion of zoonotic viruses per species is predicted by phylogenetic relatedness to humans, host taxonomy and human population within a species range—which may reflect human–wildlife contact. We demonstrate that bats harbour a significantly higher proportion of zoonotic viruses than all other mammalian orders. We also identify the taxa and geographic regions with the largest estimated number of ‘missing viruses’ and ‘missing zoonoses’ and therefore of highest value for future surveillance. We then show that phylogenetic host breadth and other viral traits are significant predictors of zoonotic potential, providing a novel framework to assess if a newly discovered mammalian virus could infect people.

Streptococcus pyogenes Infection in a Free-Living European Hedgehog (Erinaceus europaeus)

Streptococcus pyogenes, a common pathogen of humans, was isolated from the carcass of a free-living European hedgehog (Erinaceus europaeus) found in northern England in June 2014. The animal had abscessation of the deep right cervical lymph node, mesenteric lymph nodes and liver. The S. pyogenes strain isolated from the lesions, peritoneal and pleural cavities was characterised as emm 28, which can be associated with invasive disease in humans. This is the first known report of S. pyogenes in a hedgehog and in any free-living wild animal that has been confirmed by gene sequencing. As close associations between wild hedgehogs and people in England are common, we hypothesise that this case might have resulted from anthroponotic infection.

Mycobacterium tuberculosis at the human/wildlife interface in a high TB burden country

This study reports on an investigation of Mycobacterium tuberculosis cases in mostly captive wild animals using molecular typing tools [Variable Number of Tandem Repeat (VNTR) typing and Restriction Fragment Length Polymorphism typing]. The investigation included cases from (i) the National Zoological Gardens of South Africa (NZG) recorded between 2002 and 2011; (ii) Johannesburg Zoo, where tuberculosis was first diagnosed in 2007 and has since been detected in three antelope species; (iii) a rehabilitation centre for vervet monkeys (Chlorocebus pygerythrus) in which M. tuberculosis was diagnosed in 2008; and (iv) incidental cases in other facilities including a sable antelope (Hippotragus niger), two unrelated cases in chacma baboons (Papio ursinus) (one of which was from a free-ranging troop) and a colony of capuchin monkeys (Cebus capucinus). Identical genetic profiles of the latter three isolates indicate the persistence of a single M. tuberculosis strain in this population since at least 2006. Results of the outbreak investigation in the captive vervet monkey colony indicate that it was caused by two unrelated strains, while all 13 M. tuberculosis isolates from 11 animal species in the NZG showed different VNTR patterns. A substantial increase in tuberculosis cases of 60% was recorded in the NZG, compared with the previous reporting period 1991-2001, and may indicate a countrywide trend of increasing spillover of human tuberculosis to wild animals. South Africa ranks among the countries with the highest-tuberculosis burden worldwide, complicated by an increasing rate of multidrug-resistant strains. Exposure and infection of captive wildlife in this high prevalence setting is therefore a growing concern for wildlife conservation but also for human health through potential spillback.

Molecular typing of Giardia duodenalis isolates from nonhuman primates housed IN a Brazilian zoo

Giardia infections in captive nonhuman primates (NHP) housed at a Brazilian zoo were investigated in order to address their zoonotic potential. Fresh fecal samples were collected from the floors of 22 enclosures where 47 primates of 18 different species were housed. The diagnosis of intestinal parasites after concentration by sedimentation and flotation methods revealed the following parasites and their frequencies: Giardia (18%); Entamoeba spp. (18%); Endolimax nana (4.5%); Iodamoeba spp. (4.5%); Oxyurid (4.5%) and Strongylid (4.5%). Genomic DNA extracted from all samples was processed by PCR methods in order to amplify fragments of gdh and tpi genes of Giardia. Amplicons were obtained from samples of Ateles belzebuth, Alouatta caraya, Alouatta fusca and Alouatta seniculus. Clear sequences were only obtained for the isolates from Ateles belzebuth (BA1), Alouatta fusca (BA2) and Alouatta caraya (BA3). According to the phenetic analyses of these sequences, all were classified as assemblage A. For the tpi gene, all three isolates were grouped into sub-assemblage AII (BA1, BA2 and BA3) whereas for the gdh gene, only BA3 was sub-assemblage AII, and the BA1 and BA2 were sub-assemblage AI. Considering the zoonotic potential of the assemblage A, and that the animals of the present study show no clinical signs of infection, the data obtained here stresses that regular coproparasitological surveys are necessary to implement preventive measures and safeguard the health of the captive animals, of their caretakers and of people visiting the zoological gardens.

Reverse zoonotic disease transmission (zooanthroponosis): a systematic review of seldom-documented human biological threats to animals

Background

Research regarding zoonotic diseases often focuses on infectious diseases animals have given to humans. However, an increasing number of reports indicate that humans are transmitting pathogens to animals. Recent examples include methicillin-resistant Staphylococcus aureus, influenza A virus, Cryptosporidium parvum, and Ascaris lumbricoides. The aim of this review was to provide an overview of published literature regarding reverse zoonoses and highlight the need for future work in this area.

Methods

An initial broad literature review yielded 4763 titles, of which 4704 were excluded as not meeting inclusion criteria. After careful screening, 56 articles (from 56 countries over three decades) with documented human-to-animal disease transmission were included in this report.

Findings

In these publications, 21 (38%) pathogens studied were bacterial, 16 (29%) were viral, 12 (21%) were parasitic, and 7 (13%) were fungal, other, or involved multiple pathogens. Effected animals included wildlife (n = 28, 50%), livestock (n = 24, 43%), companion animals (n = 13, 23%), and various other animals or animals not explicitly mentioned (n = 2, 4%). Published reports of reverse zoonoses transmission occurred in every continent except Antarctica therefore indicating a worldwide disease threat.

Interpretation

As we see a global increase in industrial animal production, the rapid movement of humans and animals, and the habitats of humans and wild animals intertwining with great complexity, the future promises more opportunities for humans to cause reverse zoonoses. Scientific research must be conducted in this area to provide a richer understanding of emerging and reemerging disease threats. As a result, multidisciplinary approaches such as One Health will be needed to mitigate these problems.

Human-Wildlife Contact and Emerging Infectious Diseases

The majority of all emerging pathogens in humans are zoonotic (nonhuman animal) in origin. Population, ecological, and behavioral changes that increase contact with wildlife exacerbate emergence of these pathogens. Anthropogenic modification of the physical environment has altered not only our risk of zoonotic infection from wildlife but also the likelihood of pathogen transmission from human to nonhuman animal populations. This is particularly the case for primates that share a number of common infections with humans. In this chapter, I use a series of case studies involving SARS, HIV, Nipah virus, Lyme disease, malaria, and Ebola to exemplify how various anthropogenic factors have facilitated pathogen transmission between human and nonhuman animal populations. The costs and benefits of primate-based ecotourism are also reviewed to better illustrate how human-wildlife contact can affect both populations. Responsible health monitoring of human-wildlife interactions is a necessary prerequisite for prevention of the transmission of future emerging infectious diseases.

Detection of methicillin-resistant Staphylococcus aureus in Iberian pigs

AIMS

Iberian pigs are bred in Spain for the production of high-value dry-cured products, whose export volumes are increasing. Animals are typically reared outdoors, although indoor farming is becoming popular. We compared carriage of methicillin-resistant Staphylococcus aureus (MRSA) in Iberian pigs, raised indoors and outdoors, with intensively farmed Standard White pigs.

METHODS AND RESULTS

From June 2007 to February 2008, 106 skin swabs were taken from Iberian pigs and 157 samples from SWP at slaughterhouses in Spain. We found that Iberian pigs carried MRSA, although with a significantly lower prevalence (30/106; 28%) than SWP (130/157; 83%). A higher prevalence of indoor Iberian pigs compared with animals reared under outdoor conditions was not significant; however, all but one positive indoor Iberian pig samples were detected from one slaughterhouse. Overall, 16 different spa types were identified, with t011 predominating in all three animal populations. A subset of isolates was characterized by MLST. Most of these belonged to ST398. MRSA isolates from Iberian pigs presented a higher susceptibility to antibiotics than those isolated from SWP.

CONCLUSIONS

Despite limited contact with humans, pigs raised outdoors are colonized by an MRSA population that genetically overlaps with that of intensively farmed pigs, although antimicrobial resistance is lower.

SIGNIFICANCE AND IMPACT OF THE STUDY

To our knowledge, this is the first detection of MRSA in food animals raised in free-range conditions.

Primates and primatologists: social contexts for interspecies pathogen transmission

Humans and nonhuman primates (NHP) interact in a variety of contexts. The frequency, duration, and intensity of interspecies interaction influence the likelihood that contact results in cross-species transmission of infectious agents. In this study, we present results of a cross-sectional survey of attendees at a national conference of primatologists, characterizing their occupational exposures to NHP. Of 116 individuals who participated in the study, 68.1% reported having worked with NHP in a field setting, 68.1% in a laboratory setting, and 24.1% at a zoo or animal sanctuary. Most subjects (N=98, 84.5%) reported having worked with multiple NHP taxa, including 46 (39.7%) who had worked with more than five distinct taxa. Sixty-nine subjects (59.5%) recalled having been scratched by a NHP and 48 (41.1%) had been bitten; 32 subjects reporting being bitten more than once. Eleven subjects (9.5%) reported having been injured by a needle containing NHP tissue or body fluids. We conclude that primatologists are at high risk for exposure to NHP-borne infectious agents. Furthermore, primatologists' varied occupational activities often bring them into contact with multiple NHP species in diverse contexts and geographic areas, over extended periods of time, making them a unique population with respect to zoonotic and anthropozoonotic disease risk.

One health: zoonoses in the exotic animal practice

Zoonoses make up approximately ¾ of today’s emerging infectious diseases; many of these zoonoses come from exotic pets and wildlife. Recent outbreaks in humans associated with nondomestic animals include Sudden Acute Respiratory Syndrome, Ebola virus, salmonellosis, and monkeypox. Expanding human populations, increased exotic pet ownership and changes in climate may contribute to increased incidence of zoonoses. Education and preventive medicine practices can be applied by veterinarians and other health professionals to reduce the risk of contracting a zoonotic disease. The health of humans, animals, and the environment must be treated as a whole to prevent the transmission of zoonoses.

Confirmed infection with intestinal schistosomiasis in semi-captive wild-born chimpanzees on Ngamba Island, Uganda

BACKGROUND

Intestinal schistosomiasis, caused by Schistosoma mansoni, is endemic to Lake Victoria, with high prevalence of the disease observed in human lakeshore communities. However, nonhuman primates have recently been overlooked as potential hosts of the disease, despite known susceptibility.

METHODS

Using a variety of stool, urine, and serological diagnostic methods, 39 semi-captive wild-born chimpanzees and 37 staff members at Ngamba Island Chimpanzee Sanctuary, Lake Victoria, Uganda, were examined for S. mansoni infection. Miracidia recovered from stool were DNA barcoded to investigate cross-over between humans and chimpanzees. The island was also surveyed for Biomphalaria intermediate host snails, which were examined for infection with S. mansoni.

RESULTS

Chimpanzees were unequivocally shown to be infected with intestinal schistosomiasis with a seroprevalence in excess of 90%. Three egg-positive cases were detected, although the sensitivity of the diagnostic tests varied due to earlier prophylactic praziquantel treatment. Miracidia hatched from chimpanzee stool revealed three DNA haplotypes commonly found in humans living throughout Lake Victoria, including staff on Ngamba Island, as well as two novel haplotypes. At one site, a snail was observed shedding schistosome cercariae.

CONCLUSIONS

The anthropozoonotic potential of intestinal schistosomiasis on Ngamba Island is greater than previously thought. Moreover, the ability of chimpanzees to void schistosome eggs capable of hatching into viable miracidia further suggests that these nonhuman primates may be capable of maintaining a local zoonotic transmission of schistosomiasis independently of humans. The implications for management of captive and wild primate populations at risk of exposure are discussed.