No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
Disease Risk Analysis in Wildlife Health Studies
... The number of activated mammae/functional teats may have acted as a selective constraint in litter size of wild mammals (Korhonen, 1992). Thus, teat functionality is an aspect that may be considered in domestication of new species (Deem, 2012). Within these species, the agouti (Dasyprocta leporina) (Linnaeus, 1758) is highly prized for its meat and one of the most consumed game species in Neotropical countries (Cummins et al., 2015;Robinson and Redford, 1991). ...
... The agouti is a rodent of an average weight of 4.5 kg. The female agouti has eight mammae, two pairs in the thoracic region and two pairs in the abdominal region (Baas et al., 1976;Deem, 2012). It is a non-seasonal breeder (Baas et al., 1976;Campos et al., 2015;Guimarães et al., 2011;Singh et al., 2014) and under captive conditions, when receiving an abundance of food with a high plane of nutrition may produce larger litters (Singh and Garcia, 2015). ...
The red-rumped agouti (Dasyprocta leporina) produces precocial young and is the most hunted and farmed game species in several Neotropical countries. An understanding of the reproductive biology, including the relationship between litter size and teat functionality is crucial for conservation management of this animal. In precocial mammals, as the red-rumped agouti, maintaining maternal contact to learn foraging patterns may be more important than the energy demands and nutritional constraints during lactation and suckling may not play important roles when compared to altricial mammals. Therefore, in this study we evaluated the relationship between mammary functionality with litter size, litter birth weight, and parturition number in captive red-rumped agouti. Functionality was assessed by manual palpation of teats from un-sedated females (N=43). We compared the average birth weight of all newborns, male newborns and female newborns among agoutis with different litter sizes and different parturitions by one way ANOVA’s, while Pearson’s Chi-squared tests were used to detect relationships between teat functionality, litter size, and parturition number. Parturition number had no effect on the mean birth weight of all young (F0.822, P > 0.05), male young (F0.80, P > 0.05) or female young (F0.66, P > 0.05) in the litters. We found (i) no significant correlations (P > 0.05) between teat functionality and litter size and (ii) no significant correlations (P > 0.05) between teat functionality and parturition number. This suggests that whilst all teat pairs were functional, functionality was a poor indicator of litter size; suggesting that female agouti young may not have a high dependency on maternal nutrition; an possible evolutionary strategy resulting in large wild populations; hence its popularity as a game species.
... A disease risk analysis (DRA) can be qualitative, quantitative or semi-quantitative and is used to direct and perform translocations more effectively (Deem 2012). DRA is a structured, evidencebased process utilised prior to translocations to maximise translocated animals' health and minimise the risk of introducing potential pathogens to the destination population (IUCN/SSC 2013). ...
The Mauritian pink pigeon Nesoenas mayeri is at risk of extinction; only 470 birds remain in the free-living population. Being a recovered bottleneck species, this population suffers from genetic loss and inbreeding depression. Genetic variation in the European Association of Zoos and Aquaria (EAZA) Ex situ Programme (EEP) population is absent from free-living birds. EEP birds will be translocated to the captive breeding colony in Mauritius for genetic rescue. A disease risk analysis for this translocation was performed, following a four-step process outlined in International Union for Conservation of Nature guidelines: 1) problem description, 2) hazard identification, 3) risk assessment and 4) risk management. Potential pathogens were assessed and categorised as low, medium or high risk. Twenty-one pathogens were medium or high risk to the pink pigeon population, requiring risk mitigation strategies. Some pathogens were considered a risk to the poultry industry or endemic wild birds. A pre-export quarantine protocol was created which includes mitigation strategies to reduce these pathogens' risk rating to low. Recommendations include 30 days quarantine; general clinical examination and visual inspection for ectoparasites and pigeon pox lesions; radiography; blood sampling, cloacal swabbing, pharyngeal swabbing, faecal sampling and crop swabbing for various pathogens; and prophylactic endoparasite and ectoparasite treatment. Due to potential impacts on poultry and endemic wild birds, additional testing for avian influenza, Newcastle disease (avian paramyxovirus-1) and Mycoplasma spp. should be considered. This protocol can guide future EEP pink pigeon translocations to Mauritius.
... stress, malnutrition, aging, comorbidity). Captive-breeding programs and wildlife translocation, while successful to prevent extinctions under some circumstances, may also facilitate the spread of microorganisms and disease if animals are translocated without com-prehensive risk analyses and proper veterinary advice (Deem, 2012;Hunter et al., 2019;Kock et al., 2010;Sainsbury & Vaughan-Higgins, 2012 Based on our results, we obtained more positive herpesvirus diagnoses from oral swabs than from ocular swabs in Galapagos tortoises; therefore, we suggest standardising the methodology to conduct long term tortoise surveillance of herpesvirus and adenovirus based on oral and cloacal swabs, respectively, and for using either PCR or qPCR protocols. We suggest the use of both adenovirus consensus primers and the specific primers described within this work when working with Galapagos tortoise samples, as specific primers may produce cleaner sequences and less false positive results than consensus primers. ...
Emerging infectious diseases (EIDs) have been reported as causes of morbidity and mortality in free-living animal populations, including turtles and tortoises, and they have even resulted in species extinctions, with human activities contributing to the spread of many of these diseases. In the Galapagos, giant tortoises are endangered due to habitat change, invasive species, and other human impacts; however, the impact of EIDs on Galapagos tortoise conservation remains understudied. To fulfil this gap, we conducted health assessments of five tortoise species from the islands of Santa Cruz, Isabela, and Española. We performed health evaluations of 454 animals and PCR testing for pathogens known to be relevant in other tortoise species. We identified two novel sequences of adenoviruses and four of herpesviruses. Based on alignments of the DNA polymerase gene and maximum likelihood phylogenetic analyses, we found both novel adenoviruses to be most closely related to red footed tortoise adenovirus 2 by nucleotide sequence and red footed tortoise adenovirus 1 based on amino acid sequence. Three of the herpesvirus sequences translated into the same deduced amino acid sequence; therefore, they may be considered the same viral species, closely related to terrapene herpesvirus 2. The fourth herpesvirus sequence was highly divergent from any sequence previously detected and is related to an eagle owl herpesvirus based on nucleotide sequence and to loggerhead oro-cutaneous herpesvirus based on amino acids. These novel viruses seem to be pathogenic for giant tortoises under specific conditions (e.g., stress). Continued screening is crucial to determine if these viruses play a role in tortoise fitness, morbidity, and survival. This information allows us to provide recommendations to the Galapagos National Park Directorate and other institutions to improve the management of these unique species both in Galapagos and globally, and for tortoise reintroduction plans throughout the archipelago.
This article is protected by copyright. All rights reserved
... Greg is the author of over 100 popular and scientific articles about invertebrates, fishes, amphibians and reptiles and speaks locally, nationally and internationally on these subjects. He's also authored or co-authored 25 book chapters related to veterinary medicine of the above-mentioned taxonomic groups and edited or co-edited four veterinary textbooks: Self Assessment Colour Review of Ornamental Fish (Manson Publishing and ISU Press, 1998) (Manson Publishing, 2008), and the multiple award winning Invertebrate Medicine (WileyBlackwell Publishing, 2006;2012). ...
Durante los días 5–9 de diciembre de 2016, el taller para desarrollar un Plan de Salud de la Vida Silvestre de Galápagos se llevó a cabo en Puerto Ayora, Galápagos. Al taller asistieron 43 participantes representantes de organizaciones estatales en Ecuador (Agencia de Regulacióny Control de la Bioseguridad y Cuarentena para Galápagos, Dirección del Parque Nacional Galápagos, Instituto Nacional de Biologíay Ministerio de Agricultura, Ganadería, Acuacultura y Pesca); universidades tanto del
Ecuador (Escuela Superior Politécnica del Litoral –Facultad de Ciencias de la Vida, Universidad Central del Ecuador, y Universidad San Francisco de Quito) como de Estados Unidos (Colorado State University; North Carolina State University College of Veterinary Medicine; University of California, Davis School of Veterinary Medicine; and College of Veterinary Medicine, University of Minnesota); funcionarios/as de organizaciones de conservación no gubernamentales con base en las Galápagos (Fundación Charles Darwin, Island Conservation, Galápagos Conservancy,Sea Shepherd, y WILDAID) así como otras organizaciones internacionales (Houston Zoo,San Diego Zoo Global, San Diego Zoo, Wildlife Conservation Society, Zoological Society of London y Fundación Pro Zoológicos).
La Visión del Plan de Salud para los próximos 25 años es la siguiente: “Un impacto
antropogénico menor y decreciente habilita ecosistemas funcionales y resilientes que
sostienen poblaciones silvestres saludables, en equilibrio con sus parásitos naturales, y cumplen con sus roles ecológicos.” Definimos parásitos
en el sentido ecológico amplio, incluyendo virus, bacterias, hongos, protozoos, helmintos,
artrópodos, y anélidos que tienen un ciclo de vida parasitario.
Las actividades del taller siguieron los procesos de trabajo de CBSG, donde los expertos ensalud de vida silvestre conformaron seis gruposde trabajo para analizar la situación actual y recomendaron prioriades de salud de las especiesnativas de Galápagos, especies domésticas ysilvestres, y sus ecosistemas. Estos grupos fueron
los siguientes:
Reptiles Endémicos de Galápagos
Aves Endémicas de Galápagos
Mamíferos Endémicos de Galápagos
Especies Introducidas e Invasoras en
Galápagos
Animales Domésticos
Protocolos y Recopilación de Datos cuando se Manipulan Animales Silvestres
Challenges that threaten the long term survival of nonhuman primates (NHP) include habitat fragmentation, hunting, and increasingly, infectious diseases. In addition to direct mortality from non-infectious diseases (e.g., hunting) and infectious diseases (e.g., Ebola), human driven alterations of environments that support NHP often contribute to a decline in population viability. This decline is frequently the result of physiological stress, poor reproduction, decreased immunity, and exposure to novel pathogens. To better understand the diseases that threaten NHP populations, a conservation medicine approach—the application of medicine to augment the conservation of wildlife and ecosystems—is imperative so that we may provide management solutions to help ensure the long-term survival of NHP. Additionally, it is crucial that we gain a better understanding of pathogens at the interface of nonhuman and human primates since the zoonotic potential may create conservation challenges; or alternatively may provide the impetus for conservation actions to be practiced (e.g., minimize bushmeat trade).
Reintroductions are increasingly utilized for the conservation of endangered avian species. To avert disease‐related failures, studies to determine disease risks should be performed prior to the implementation of any avian reintroduction program. The presence, and prevalence, of disease‐causing agents in both the source population and in birds at the site of reintroduction may help better direct reintroduction programs. In this study, we determined the prevalence of parasitic and pathogenic agents in chickens and wild birds on Floreana Island prior to the reintroduction of the critically endangered Floreana mockingbird Mimus trifasciatus. We investigated avian diseases on Floreana in 175 chickens and 274 wild birds. In addition to a number of clinical abnormalities, chickens tested positive for antibodies to paramyxovirus‐1 (30%), adenovirus (11.3%) and seven other pathogens of concern for both domestic and wild birds. Wild birds on Floreana had antibodies to paramyxovirus‐1 (3.0%) and adenovirus (2.4%). This is the first report of possible spillover of disease from domestic to wild birds in the archipelago. Based on these findings, and the lack of disease exposure documented in the source mockingbird population, we recommend improved poultry biosecurity measures on Floreana, and that mockingbirds only be reintroduced in areas on the island far from poultry and human presence and following further prerelease analyses. This study provides valuable data for the reintroduction of this iconic bird species and serves as a template for other avian reintroduction programs.
Among biologists, the awareness of infectious diseases and their population-, community-, and ecosystem-level impacts has increased dramatically over the past de cade. This growth in interest seems to have paralleled an unpre ce dented global rise in the appearance of new pathogens, the spread of old pathogens, and changes in the pathology of many infectious agents in both humans and wildlife. However, the paucity of historical data makes it diffi cult to assess whether these current patterns represent a new or unique threat to ecosystem health. To evaluate the level of threat infectious diseases may pose to ecosystems, it is important to examine if, how, and why the impacts of diseases are changing in the modern world. Rec ords of disease outbreaks in humans and livestock go back thousands of years, but relatively little historical information exists about infectious disease dynamics in natural ecosystems. As such, a fundamental question for disease ecologists is whether the ecosystem-level impacts of wildlife diseases are increasing on a global scale. In addition, given the mounting evidence implicating anthropogenic environmental changes in the emergence of various human infectious diseases, a second critical question is whether humans also contribute to the increased emergence and impact of infectious diseases in natural ecosystems. In this chapter we explore both questions by evaluating existing evidence from the literature and outline a research agenda for moving the fi eld of disease ecol ogy toward more defi nitive answers to these pressing questions. The research agenda we propose includes retrospective analyses of existing data on plant, animal, and human diseases to explore historical patterns of pathogen distribution, diversity, and prevalence; prospective long-term research projects to monitor infectious diseases in natural populations and communities; and experimental testing of probable drivers of disease emergence. For this research agenda to meet the ultimate objective of an increased capability to forecast disease outbreaks and to mitigate the negative impacts of these diseases, it must have multiple, integrated foci, each of which contributes to the understanding of wildlife management, ecosystem conservation, and human health in our changing world.
Disease plays a significant role as a risk factor in wildlife conservation programmes involving animal movements, such as translocation, transportation among zoos or reintroduction. However, the traditional ‘zero-risk tolerance’ approach to the assessment of disease risk in these programmes is unattainable and unmanageable, often leading to an excessively cautious attitude towards the risks that are involved. It is therefore critically important to develop a comprehensive, unified and broadly applicable set of descriptive and analytical tools that can more realistically and accurately assess disease-based risks in conservation-based animal-movement programmes. The Conservation Breeding Specialist Group, of the IUCN – World Conservation Union, has brought together an international team of wildlife medicine professionals to construct a set of qualitative and quantitative tools to assess disease risk. The tools are flexible, intuitive and span a broad range of complexities. These tools are designed to enable professionals to incorporate not only published, statistically valid data but also to make reasonable decisions under conditions of uncertainty, and to capture valuable information from more basic field or clinical experience. Selected tools from the larger ‘toolkit’ are described here, with examples from actual case studies where available.
We developed and evaluated a methodology to prioritise pathogens for a wildlife disease surveillance strategy in New Zealand. The methodology, termed 'rapid risk analysis' was based on the import risk analysis framework recommended by the Office Internationale des Epizooties (OIE), and involved: hazard identification, risk estimation, and ranking of 48 exotic and 34 endemic wildlife pathogens. The risk assessment was more rapid than a full quantitative assessment through the use of a semi-quantitative approach to score pathogens for probability of entry to NZ (release assessment), likelihood of spread (exposure assessment) and consequences in free-living wildlife, captive wildlife, humans, livestock and companion animals. Risk was estimated by multiplying the scores for the probability of entry to New Zealand by the likelihood of spread by the consequences for free-living wildlife, humans and livestock. The rapid risk analysis methodology produced scores that were sufficiently differentiated between pathogens to be useful for ranking them on the basis of risk. Ranking pathogens on the basis of the risk estimate for each population sector provided an opportunity to identify the priorities within each sector alone thus avoiding value-laden comparisons between sectors. Ranking pathogens across all three population sectors by summing the risk estimate for each sector provided a comparison of total risk which may be useful for resource allocation decisions at national level. Ranking pathogens within each wildlife taxonomic group using the total risk estimate was most useful for developing specific surveillance strategies for each group.
With increasing awareness of disease as an endangering process, an assessment of which pathogens might pose a problem and their patterns of infection in natural hosts is necessary. This paper examines the exposure of sympatric Ethiopian wolves (Canis
simensis) and domestic dogs to canine distemper virus (CDV), canine adenovirus (CAV) and canine parvovirus (CPV) in the Bale region, Ethiopia and then relates these data to population trends of wolves. Wolves (n = 30) sampled between 1989 and 1992 had been exposed to CDV, CAV and CPV, but only CAV might be able to persist in this wolf population. Anecdotal and serological evidence suggested that an epidemic of CDV occurred in the dog population of the Bale Mountains National Park (BMNP) in 1992–93. All park dogs born since this time were seronegative to CDV, although some young dogs in the nearby urban population were seropositive. Despite evidence of CAV infection in wolves, none of the dogs sampled in the park were CAV seropositive, although this virus appeared highly seroprevalent and endemic in urban dogs. All dogs tested for CPV antibodies were seropositive. The BMNP wolf population declined in the late 1980s and early 1990s, with rabies responsible for a dramatic population reduction between 1990 and 1992. Although the population declined further up until 1995, it is not possible to assess whether the concurrent canine distemper epidemic in park dogs also affected wolves. Nevertheless, with evidence of rabies, CDV, CAV and CPV infections in sympatric domestic dogs and Ethiopian wolves, canid diseases clearly pose a significant threat to the future persistence of this Ethiopian wolf population.
Infectious disease constitutes a substantial threat to the viability of endangered species. Population viability analysis (PVA) can be a useful tool for directing conservation management when decisions must be made and information is absent or incomplete. Incorporating epidemiological dynamics explicitly into a PVA framework is technically challenging, but here we make a first attempt to integrate formal stochastic models of the combined dynamics of rabies and canine distemper into a PVA of the Ethiopian wolf ( Canis simensis), a critically endangered canid. In the absence of disease, populations in habitat patches of every size were remarkably stable and persistent. When rabies virus was introduced, epidemics, assumed to arise from sporadic dog-to-wolf transmission, caused extinction probabilities over 50 years to rise linearly with the force of infection from the dog reservoir and particularly steeply in smaller populations. Sensitivity analysis revealed that although the overall pattern of results was not altered fundamentally by small to moderate changes in disease-transmission rates or the way in which interpack disease transmission was modeled, results were sensitive to the process of female recruitment to male-only packs. Completely protecting wolf populations from rabies through vaccination is likely to be impractical, but the model suggested that direct vaccination of as few as 20–40% of wolves against rabies might be sufficient to eliminate the largest epidemics and therefore protect populations from the very low densities that make recovery unlikely. Additional simulations suggested that the affect of periodic epidemics of canine distemper virus on wolf population persistence was likely to be slight, even when modeled together with rabies. From a management perspective, our results suggest that conservation action to protect even the smallest populations of Ethiopian wolves from rabies is both worthwhile and urgent.
Contact between humans and nonhuman primates (NHPs) frequently occurs at monkey temples (religious sites that have become associated with free-ranging populations of NHPs) in Asia, creating the potential for NHP-human disease transmission. In March 2003 a multidisciplinary panel of experts participated in a workshop designed to model the risk of NHP-human pathogen transmission. The panel developed a risk assessment model to describe the likelihood of cross-species transmission of simian foamy virus (SFV) from temple macaques (Macaca fascicularis) to visitors at monkey temples. SFV is an enzootic simian retrovirus that has been shown to be transmitted from NHPs to humans. In operationalizing the model field data, laboratory data and expert opinions were used to estimate the likelihood of SFV transmission within this context. This model sets the stage for a discussion about modeling as a risk assessment tool and the kinds of data that are required to accurately predict transmission.
Disease outbreaks, either in isolation or in concert with other risk factors, can pose serious threats to the long-term persistence of mammal populations, and these risks become elevated as population size decreases and/or population isolation increases. Many chimpanzee study sites are increasingly isolated by loss of habitat due to human encroachment, and managers of parks that contain chimpanzees perceive that disease outbreaks have been and continue to be significant causes of mortality for chimpanzees. Major epidemics at Gombe National Park include suspected polio in 1966; respiratory diseases in 1968, 1987, 1996, 2000, and 2002; and sarcoptic mange in 1997. These outbreaks have led park managers and researchers working in Gombe to conclude that disease poses a substantial risk to the long-term survival of Gombe's chimpanzee population. We surveyed behavioral data records spanning 44 years for health-related data and found a combination of standardized and nonstandardized data for the entire period. Here we present the types of data found during the survey, discuss the usefulness of these data in the context of risk assessment, and describe how our current monitoring effort at Gombe was designed based on our findings.
Emerging infectious diseases are a key threat to conservation and public health, yet predicting and preventing their emergence is notoriously difficult. We devised a predictive model for the introduction of a zoonotic vector-borne pathogen by considering each of the pathways by which it may be introduced to a new area and comparing the relative risk of each pathway. This framework is an adaptation of pest introduction models and estimates the number of infectious individuals arriving in a location and the duration of their infectivity. We used it to determine the most likely route for the introduction of West Nile virus to Galápagos and measures that can be taken to reduce the risk of introduction. The introduction of this highly pathogenic virus to this unique World Heritage Site could have devastating consequences, similar to those seen following introductions of pathogens into other endemic island faunas. Our model identified the transport of mosquitoes on airplanes as the highest risk for West Nile virus introduction. Pathogen dissemination through avian migration and the transportation of day-old chickens appeared to be less important pathways. Infected humans and mosquitoes transported in sea containers, in tires, or by wind all represented much lower risk. Our risk-assessment framework has broad applicability to other pathogens and other regions and depends only on the availability of data on the transport of goods and animals and the epidemiology of the pathogen.
Improved understanding and assessment of the complex factors associated with disease emergence and spread will lead to better management and thus reduction of risk for disease occurrence. Specific biological, ecologic, environmental, and societal factors have been identified that precede emerging infections. Based on these factors, a qualitative tool was developed to assess risk for disease emergence and spread. Within this tool, three separate assessment elements were developed: novel disease evolution, pathways by which a disease agent could be introduced into a country, and domestic spread from the location of introduction or evolution. Risk factors identified for each of the three elements consist of specific descriptions of production practices, consumer demand, trade, health conditions, and environmental conditions, and are categorized as primary or secondary. Using this tool, those factors contributing greatest to risk of disease emergence can be identified and targeted for mitigation. In addition, risk can be monitored over time, focusing on factors that are primary or that have the greatest potential for increasing disease emergence risk.