The ecology of human-caused mortality for a protected large carnivore.

Mitigating human-caused mortality for large carnivores is a pressing global challenge for wildlife conservation. However, mortality is almost exclusively studied at local (within-population) scales creating a mismatch between our understanding of risk and the spatial extent most relevant to conservation and management of wide-ranging species. Here, we quantified mortality for 590 radio-collared mountain lions statewide across their distribution in California to identify drivers of human-caused mortality and investigate whether human-caused mortality is additive or compensatory. Human-caused mortality, primarily from conflict management and vehicles, exceeded natural mortality despite mountain lions being protected from hunting. Our data indicate that human-caused mortality is additive to natural mortality as population-level survival decreased as a function of increasing human-caused mortality and natural mortality did not decrease with increased human-caused mortality. Mortality risk increased for mountain lions closer to rural development and decreased in areas with higher proportions of citizens voting to support environmental initiatives. Thus, the presence of human infrastructure and variation in the mindset of humans sharing landscapes with mountain lions appear to be primary drivers of risk. We show that human-caused mortality can reduce population-level survival of large carnivores across large spatial scales, even when they are protected from hunting.

Feline Leukemia Virus Frequently Spills Over from Domestic Cats to North American Pumas.

Feline leukemia virus (FeLV) is a gammaretrovirus with horizontally transmitted and endogenous forms. Domestic cats are the primary reservoir species, but FeLV outbreaks in endangered Florida panthers and Iberian lynxes have resulted in mortalities. To assess prevalence and interspecific/intraspecific transmission, we conducted an extensive survey and phylogenetic analysis of FeLV infection in free-ranging pumas (n = 641) and bobcats (n = 212) and shelter domestic cats (n = 304). Samples were collected from coincident habitats across the United States between 1985 and 2018. FeLV infection was detected in 3.12% of the puma samples, 0.47% of the bobcat samples, and 6.25% of the domestic cat samples analyzed. Puma prevalence varied by location, with Florida having the highest rate of infection. FeLV env sequences revealed variation among isolates, and we identified two distinct clades. Both progressive and regressive infections were identified in cats and pumas. Based on the time and location of sampling and phylogenetic analysis, we inferred 3 spillover events between domestic cats and pumas; 3 puma-to-puma transmissions in Florida were inferred. An additional 14 infections in pumas likely represented spillover events following contact with reservoir host domestic cat populations. Our data provide evidence that FeLV transmission from domestic cats to pumas occurs widely across the United States, and puma-to-puma transmission may occur in genetically and geographically constrained populations. IMPORTANCE Feline leukemia virus (FeLV) is a retrovirus that primarily affects domestic cats. Close interactions with domestic cats, including predation, can lead to the interspecific transmission of the virus to pumas, bobcats, or other feline species. Some infected individuals develop progressive infections, which are associated with clinical signs of disease and can result in mortality. Therefore, outbreaks of FeLV in wildlife, including the North American puma and the endangered Florida panther, are of high conservation concern. This work provides a greater understanding of the dynamics of the transmission of FeLV between domestic cats and wild felids and presents evidence of multiple spillover events and infections in all sampled populations. These findings highlight the concern for pathogen spillover from domestic animals to wildlife but also identify an opportunity to understand viral evolution following cross-species transmissions more broadly.

Extinction vortex dynamics of top predators isolated by urbanization.

Extinction risk is elevated in small, isolated populations due to demographic and genetic interactions. Therefore, it is critical to model these processes realistically in population viability analyses (PVA) to inform local management and contribute to a greater understanding of mechanisms within the extinction vortex. We conducted PVA's for two small mountain lion populations isolated by urbanization in southern California to predict population growth, extinction probability, and loss of genetic diversity with empirical data. Specifically, we (1) provide the first PVA for isolated mountain lions in the Santa Ana Mountains (SAM) that considers both demographic and genetic risk factors and (2) test the hypothesis that variation in abundance and mortality between the SAM and Santa Monica Mountains (SMM) result in differences in population growth, loss of heterozygosity, and extinction probability. Our models predicted 16-21% probability of local extinction in the SAM due purely to demographic processes over 50 yr with current low levels or no immigration. Our models also predicted that genetic diversity will further erode in the SAM such that concern regarding inbreeding depression is warranted unless gene flow is increased, and that if inbreeding depression occurs, rapid local extinction will be highly likely. Dynamics of the two populations were broadly similar, but they also exhibited differences driven by larger population size and higher mortality in the SAM. Density-independent scenarios predicted a rapidly increasing population in the SMM, whereas growth potential did not differ from a stable trend in the SAM. Demographic extinction probability and loss of heterozygosity were greater in the SMM for density-dependent scenarios without immigration. However, higher levels of immigration had stronger, positive influences on both demographic viability and retention of genetic diversity in the SMM driven by lower abundance and higher adult survival. Our results elucidate demographic and genetic threats to small populations within the extinction vortex, and how these vary relative to demographic structure. Importantly, simulating seemingly attainable increases in connectivity was sufficient to greatly reduce extinction probability. Our work highlights that conservation of large carnivores is achievable within urbanized landscapes, but requires land protection, connectivity, and strategies to promote coexistence with humans.

Pathogen exposure varies widely among sympatric populations of wild and domestic felids across the United States.

Understanding how landscape, host, and pathogen traits contribute to disease exposure requires systematic evaluations of pathogens within and among host species and geographic regions. The relative importance of these attributes is critical for management of wildlife and mitigating domestic animal and human disease, particularly given rapid ecological changes, such as urbanization. We screened > 1000 samples from sympatric populations of puma (Puma concolor), bobcat (Lynx rufus), and domestic cat (Felis catus) across urban gradients in six sites, representing three regions, in North America for exposure to a representative suite of bacterial, protozoal, and viral pathogens (Bartonella sp., Toxoplasma gondii, feline herpesvirus-1, feline panleukopenea virus, feline calicivirus, and feline immunodeficiency virus). We evaluated prevalence within each species, and examined host trait and land cover determinants of exposure; providing an unprecedented analysis of factors relating to potential for infections in domesticated and wild felids. Prevalence differed among host species (highest for puma and lowest for domestic cat) and was greater for indirectly transmitted pathogens. Sex was inconsistently predictive of exposure to directly transmitted pathogens only, and age infrequently predictive of both direct and indirectly transmitted pathogens. Determinants of pathogen exposure were widely divergent between the wild felid species. For puma, suburban land use predicted increased exposure to Bartonella sp. in southern California, and FHV-1 exposure increased near urban edges in Florida. This may suggest interspecific transmission with domestic cats via flea vectors (California) and direct contact (Florida) around urban boundaries. Bobcats captured near urban areas had increased exposure to T. gondii in Florida, suggesting an urban source of prey Bobcats captured near urban areas in Colorado and Florida had higher FIV exposure, possibly suggesting increased intraspecific interactions through pile-up of home ranges. Beyond these regional and pathogen specific relationships, proximity to the wildland-urban interface did not generally increase the probability of disease exposure in wild or domestic felids, empha- sizing the importance of local ecological determinants. Indeed, pathogen exposure was often negatively associated with the wildland-urban interface for all felids. Our analyses suggest cross-species pathogen transmission events around this interface may be infrequent, but followed by self-sustaining propagation within the new host species. virus; puma (Puma concolor); Toxoplasma gondii; urbanization.

Novel gammaherpesviruses in North American domestic cats, bobcats, and pumas: identification, prevalence, and risk factors.

UNLABELLED: Gammaherpesviruses (GHVs) are a diverse and rapidly expanding group of viruses associated with a variety of disease conditions in humans and animals. To identify felid GHVs, we screened domestic cat (Felis catus), bobcat (Lynx rufus), and puma (Puma concolor) blood cell DNA samples from California, Colorado, and Florida using a degenerate pan-GHV PCR. Additional pan-GHV and long-distance PCRs were used to sequence a contiguous 3.4-kb region of each putative virus species, including partial glycoprotein B and DNA polymerase genes. We identified three novel GHVs, each present predominantly in one felid species: Felis catus GHV 1 (FcaGHV1) in domestic cats, Lynx rufus GHV 1 (LruGHV1) in bobcats, and Puma concolor GHV 1 (PcoGHV1) in pumas. To estimate infection prevalence, we developed real-time quantitative PCR assays for each virus and screened additional DNA samples from all three species (n = 282). FcaGHV1 was detected in 16% of domestic cats across all study sites. LruGHV1 was detected in 47% of bobcats and 13% of pumas across all study sites, suggesting relatively common interspecific transmission. PcoGHV1 was detected in 6% of pumas, all from a specific region of Southern California. The risk of infection for each host varied with geographic location. Age was a positive risk factor for bobcat LruGHV1 infection, and age and being male were risk factors for domestic cat FcaGHV1 infection. Further characterization of these viruses may have significant health implications for domestic cats and may aid studies of free-ranging felid ecology. IMPORTANCE: Gammaherpesviruses (GHVs) establish lifelong infection in many animal species and can cause cancer and other diseases in humans and animals. In this study, we identified the DNA sequences of three GHVs present in the blood of domestic cats (Felis catus), bobcats (Lynx rufus), and pumas (Puma concolor; also known as mountain lions, cougars, and panthers). We found that these viruses were closely related to, but distinct from, other known GHVs of animals and represent the first GHVs identified to be native to these feline species. We developed techniques to rapidly and specifically detect the DNA of these viruses in feline blood and found that the domestic cat and bobcat viruses were widespread across the United States. In contrast, puma virus was found only in a specific region of Southern California. Surprisingly, the bobcat virus was also detected in some pumas, suggesting relatively common virus transmission between these species. Adult domestic cats and bobcats were at greater risk for infection than juveniles. Male domestic cats were at greater risk for infection than females. This study identifies three new viruses that are widespread in three feline species, indicates risk factors for infection that may relate to the route of infection, and demonstrates cross-species transmission between bobcats and pumas. These newly identified viruses may have important effects on feline health and ecology.

First reproductive signs of inbreeding depression in Southern California male mountain lions (Puma concolor).

Long-term studies of mountain lions (Puma concolor) in Southern California have documented persistent small population sizes and the lowest genetic variation of any mountain lion population, except for the Federally endangered mountain lion subspecies, the Florida panther (Puma concolor coryi). There is overwhelming molecular evidence supporting inbreeding and low genetic diversity in these Southern California populations but there is a lack of phenotypical evidence of inbreeding depression. The primary goal of this study was to assess male mountain lions, in Southern California, for teratospermia (>60% abnormal sperm production), one of the first signs of inbreeding depression in mountain lions that are associated with decreased reproduction and population decline. From December 2019 to December 2020, we surveyed mountain lions during live captures, after mortality events, and in images collected from camera traps in the following populations: Santa Monica Mountains, Santa Susana Mountains, Santa Ana Mountains, and the Eastern Peninsular Range. Mountain lions were sampled for known physical abnormalities associated with inbreeding depression such as teratospermia, cryptorchidism, and distal tail kinks. For teratospermia, we extracted testes from five males post-mortem to assess sperm morphology. Epididymal sperm evaluations revealed all males were teratospermic. Across all samples, on average, 93% of observed spermatozoa were abnormal. We physically examined 32 mountain lions (males and females) for distal tail kinks, and we observed one individual affected. We examined 15 male mountain lions for cryptorchidism, and we observed one unilaterally cryptorchid male and one male with testes that differed significantly in size, likely reflecting asynchronous migration of the testes during puberty. Further, we identified three other animals in camera-trap images that had distal tail kinks, for a total of four. In conclusion, from December 2019 to December 2020, we identified nine individuals exhibiting physical signs of inbreeding depression. These reproductive and physical signs of inbreeding depression in Southern California mountain lions increase the urgency of conservation efforts in the region.

Multi-population puma connectivity could restore genomic diversity to at-risk coastal populations in California.

Urbanization is decreasing wildlife habitat and connectivity worldwide, including for apex predators, such as the puma (Puma concolor). Puma populations along California's central and southern coastal habitats have experienced rapid fragmentation from development, leading to calls for demographic and genetic management. To address urgent conservation genomic concerns, we used double-digest restriction-site associated DNA (ddRAD) sequencing to analyze 16,285 genome-wide single-nucleotide polymorphisms (SNPs) from 401 pumas sampled broadly across the state. Our analyses indicated support for 4-10 geographically nested, broad- to fine-scale genetic clusters. At the broadest scale, the four genetic clusters had high genetic diversity and exhibited low linkage disequilibrium, indicating that pumas have retained genomic diversity statewide. However, multiple lines of evidence indicated substructure, including 10 finer-scale genetic clusters, some of which exhibited fixed alleles and linkage disequilibrium. Fragmented populations along the Southern Coast and Central Coast had particularly low genetic diversity and strong linkage disequilibrium, indicating genetic drift and close inbreeding. Our results demonstrate that genetically at risk populations are typically nested within a broader-scale group of interconnected populations that collectively retain high genetic diversity and heterogenous fixations. Thus, extant variation at the broader scale has potential to restore diversity to local populations if management actions can enhance vital gene flow and recombine locally sequestered genetic diversity. These state- and genome-wide results are critically important for science-based conservation and management practices. Our nested population genomic analysis highlights the information that can be gained from population genomic studies aiming to provide guidance for the conservation of fragmented populations.

Multi-level, multi-scale resource selection functions and resistance surfaces for conservation planning: Pumas as a case study.

The importance of examining multiple hierarchical levels when modeling resource use for wildlife has been acknowledged for decades. Multi-level resource selection functions have recently been promoted as a method to synthesize resource use across nested organizational levels into a single predictive surface. Analyzing multiple scales of selection within each hierarchical level further strengthens multi-level resource selection functions. We extend this multi-level, multi-scale framework to modeling resistance for wildlife by combining multi-scale resistance surfaces from two data types, genetic and movement. Resistance estimation has typically been conducted with one of these data types, or compared between the two. However, we contend it is not an either/or issue and that resistance may be better-modeled using a combination of resistance surfaces that represent processes at different hierarchical levels. Resistance surfaces estimated from genetic data characterize temporally broad-scale dispersal and successful breeding over generations, whereas resistance surfaces estimated from movement data represent fine-scale travel and contextualized movement decisions. We used telemetry and genetic data from a long-term study on pumas (Puma concolor) in a highly developed landscape in southern California to develop a multi-level, multi-scale resource selection function and a multi-level, multi-scale resistance surface. We used these multi-level, multi-scale surfaces to identify resource use patches and resistant kernel corridors. Across levels, we found puma avoided urban, agricultural areas, and roads and preferred riparian areas and more rugged terrain. For other landscape features, selection differed among levels, as did the scales of selection for each feature. With these results, we developed a conservation plan for one of the most isolated puma populations in the U.S. Our approach captured a wide spectrum of ecological relationships for a population, resulted in effective conservation planning, and can be readily applied to other wildlife species.

A single migrant enhances the genetic diversity of an inbred puma population.

Migration is essential for maintaining genetic diversity among populations, and pumas (Puma concolor) provide an excellent model for studying the genetic impacts of migrants on populations isolated by increasing human development. In densely populated southern California, USA, puma populations on the east and west side of interstate highway 15 (I-15) have become fragmented into a small inbred population on the west side (Santa Ana Mountains) and a relatively larger, more diverse population on the east side (Eastern Peninsular Range). From 146 sampled pumas, genetic analyses indicate seven pumas crossed I-15 over the last 15 years, including four males from west to east, and three males from east to west. However, only a single migrant (named M86) was detected to have produced offspring and contribute to gene flow across the I-15 barrier. Prior to the M86 migration, the Santa Ana population exhibited inbreeding and had significantly lower genetic diversity than the Eastern Peninsular Range population. After M86 emigrated, he sired 11 offspring with Santa Ana females, decreasing inbreeding measures and raising heterozygosity to levels similar to pumas in the Eastern Peninsular Range. The emigration of M86 also introduced new alleles into the Santa Ana population, although allelic richness still remained significantly lower than the Eastern Peninsular population. Our results clearly show the benefit of a single migrant to the genetics of a small, isolated population. However, ongoing development and habitat loss on both sides of I-15 will increasingly strengthen the barrier to successful migration. Further monitoring, and potential human intervention, including minimizing development effects on connectivity, adding or improving freeway crossing structures, or animal translocation, may be needed to ensure adequate gene flow and long-term persistence of the Santa Ana puma population.

Surveillance for highly pathogenic influenza A viruses in California during 2014-2015 provides insights into viral evolutionary pathways and the spatiotemporal extent of viruses in the Pacific Americas Flyway.

We used surveillance data collected in California before, concurrent with, and subsequent to an outbreak of highly pathogenic (HP) clade 2.3.4.4 influenza A viruses (IAVs) in 2014-2015 to (i) evaluate IAV prevalence in waterfowl, (ii) assess the evidence for spill-over infections in marine mammals and (iii) genetically characterize low-pathogenic (LP) and HP IAVs to refine inference on the spatiotemporal extent of HP genome constellations and to evaluate possible evolutionary pathways. We screened samples from 1496 waterfowl and 1142 marine mammals collected from April 2014 to August 2015 and detected IAV RNA in 159 samples collected from birds (n=157) and pinnipeds (n=2). HP IAV RNA was identified in three samples originating from American wigeon (Anas americana). Genetic sequence data were generated for a clade 2.3.4.4 HP IAV-positive diagnostic sample and 57 LP IAV isolates. Phylogenetic analyses revealed that the HP IAV was a reassortant H5N8 virus with gene segments closely related to LP IAVs detected in mallards (Anas platyrhynchos) sampled in California and other IAVs detected in wild birds sampled within the Pacific Americas Flyway. In addition, our analysis provided support for common ancestry between LP IAVs recovered from waterfowl sampled in California and gene segments of reassortant HP H5N1 IAVs detected in British Columbia, Canada and Washington, USA. Our investigation provides evidence that waterfowl are likely to have played a role in the evolution of reassortant HP IAVs in the Pacific Americas Flyway during 2014-2015, whereas we did not find support for spill-over infections in potential pinniped hosts.

Pathology and Epidemiology of Ceruminous Gland Tumors among Endangered Santa Catalina Island Foxes (Urocyon littoralis catalinae) in the Channel Islands, USA.

In this study, we examined the prevalence, pathology, and epidemiology of tumors in free-ranging island foxes occurring on three islands in the California Channel Islands, USA. We found a remarkably high prevalence of ceruminous gland tumors in endangered foxes (Urocyon littoralis catalinae) occurring on Santa Catalina Island (SCA)--48.9% of the dead foxes examined from 2001-2008 had tumors in their ears, and tumors were found in 52.2% of randomly-selected mature (≥ 4 years) foxes captured in 2007-2008, representing one of the highest prevalences of tumors ever documented in a wildlife population. In contrast, no tumors were detected in foxes from San Nicolas Island or San Clemente Island, although ear mites (Otodectes cynotis), a predisposing factor for ceruminous gland tumors in dogs and cats, were highly prevalent on all three islands. On SCA, otitis externa secondary to ear mite infection was highly correlated with ceruminous gland hyperplasia (CGH), and tumors were significantly associated with the severity of CGH, ceruminous gland dysplasia, and age group (older foxes). We propose a conceptual model for the formation of ceruminous gland tumors in foxes on SCA that is based on persistent, ubiquitous infection with ear mites, and an innate, over exuberant inflammatory and hyperplastic response of SCA foxes to these mites. Foxes on SCA are now opportunistically treated with acaricides in an attempt to reduce mite infections and the morbidity and mortality associated with this highly prevalent tumor.

Ear Mite Removal in the Santa Catalina Island Fox (Urocyon littoralis catalinae): Controlling Risk Factors for Cancer Development.

Ear mites (Otodectes cynotis) and ear canal tumors are highly prevalent among federally endangered Island foxes (Urocyon littoralis catalinae) living on Santa Catalina Island off the coast of Southern California. Since studies began in the 1990s, nearly all foxes examined were found to be infected with ear mites, and ceruminous gland tumors (carcinomas and adenomas) were detected in approximately half of all foxes ≥ 4 years of age. We hypothesized that reduction of ear mite infection would reduce otitis externa and ceruminous gland hyperplasia, a risk factor for tumor development. In this study, we conducted a randomized field trial to assess the impact of acaricide treatment on ear mite prevalence and intensity of infection, otitis externa, ceruminous gland hyperplasia, and mite-specific IgG and IgE antibody levels. Treatment was highly effective at eliminating mites and reducing otitis externa and ceruminous gland hyperplasia, and mite-specific IgG antibody levels were significantly lower among uninfected foxes. Ceruminous gland hyperplasia increased in the chronically infected, untreated foxes during the six month study. Our results provide compelling evidence that acaricide treatment is an effective means of reducing ear mites, and that mite removal in turn reduces ear lesions and mite-specific IgG antibody levels in Santa Catalina Island foxes. This study has advanced our understanding of the underlying pathogenesis which results in ceruminous gland tumors, and has helped inform management decisions that impact species conservation.

Survival and Mortality of Pumas (Puma concolor) in a Fragmented, Urbanizing Landscape.

Wide-ranging large carnivores pose myriad challenges for conservation, especially in highly fragmented landscapes. Over a 13-year period, we combined monitoring of radio collared pumas (Puma concolor) with complementary multi-generational genetic analyses to inform puma conservation in southern California, USA. Our goals were to generate survivorship estimates, determine causes of mortality, identify barriers to movement, and determine the genetic and demographic challenges to puma persistence among >20,000,000 people and extensive urban, suburban, and exurban development. Despite protection from hunting, annual survival for radio collared pumas was surprisingly low (55.8%), and humans caused the majority of puma deaths. The most common sources of mortality were vehicle collisions (28% of deaths), and mortalities resulting from depredation permits issued after pumas killed domestic animals (17% of deaths). Other human-caused mortalities included illegal shootings, public safety removals, and human-caused wildfire. An interstate highway (I-15) bisecting this study area, and associated development, have created a nearly impermeable barrier to puma movements, resulting in severe genetic restriction and demographic isolation of the small puma population (n ~ 17-27 adults) in the Santa Ana Mountains west of I-15. Highways that bisect habitat or divide remaining "conserved" habitat, and associated ongoing development, threaten to further subdivide this already fragmented puma population and increase threats to survival. This study highlights the importance of combining demographic and genetic analyses, and illustrates that in the absence of effective measures to reduce mortality and enhance safe movement across highways, translocation of pumas, such as was done with the endangered Florida panther (P. c. coryi), may ultimately be necessary to prevent further genetic decline and ensure persistence of the Santa Ana Mountains population.

Fractured genetic connectivity threatens a southern california puma (Puma concolor) population.

Pumas (Puma concolor; also known as mountain lions and cougars) in southern California live among a burgeoning human population of roughly 20 million people. Yet little is known of the consequences of attendant habitat loss and fragmentation, and human-caused puma mortality to puma population viability and genetic diversity. We examined genetic status of pumas in coastal mountains within the Peninsular Ranges south of Los Angeles, in San Diego, Riverside, and Orange counties. The Santa Ana Mountains are bounded by urbanization to the west, north, and east, and are separated from the eastern Peninsular Ranges to the southeast by a ten lane interstate highway (I-15). We analyzed DNA samples from 97 pumas sampled between 2001 and 2012. Genotypic data for forty-six microsatellite loci revealed that pumas sampled in the Santa Ana Mountains (n = 42) displayed lower genetic diversity than pumas from nearly every other region in California tested (n = 257), including those living in the Peninsular Ranges immediately to the east across I-15 (n = 55). Santa Ana Mountains pumas had high average pairwise relatedness, high individual internal relatedness, a low estimated effective population size, and strong evidence of a bottleneck and isolation from other populations in California. These and ecological findings provide clear evidence that Santa Ana Mountains pumas have been experiencing genetic impacts related to barriers to gene flow, and are a warning signal to wildlife managers and land use planners that mitigation efforts will be needed to stem further genetic and demographic decay in the Santa Ana Mountains puma population.

Biochemical and hematologic reference intervals for the endangered island fox (Urocyon littoralis).

Hematologic and serum biochemical data collected must be interpreted by comparison with normal reference intervals generated from healthy animals, within a similar population, because many blood parameters are influenced by diet, environment, and stress. Species-specific reference intervals for the endangered island fox (Urocyon littoralis) are not available. We reviewed hematology and serum biochemistry panels from 280 island foxes sampled from 1999-2008 and established normal reference intervals from clinically healthy foxes using a nonparametric approach. Blood parameters were analyzed for differences in age, sex, island of origin, and captivity status. Alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, and creatine kinase activities, as well as calcium and phosphorus concentrations, were significantly higher in juveniles than in adults, but total protein and globulin concentration was lower for juveniles than for adults. Lymphocyte and eosinophil counts, and blood urea nitrogen (BUN) concentration, in foxes from the northern Channel islands of California, USA (Santa Cruz, Santa Rosa, and San Miguel) were higher when compared with foxes from Santa Catalina Island to the south. Higher lymphocyte and eosinophil numbers in the northern island foxes may be associated with increased levels of parasitism on the northern islands. Differences in BUN concentration in both free-ranging and captive foxes may reflect dietary differences among islands. Although aggressive conservation programs have been enacted, island foxes are still susceptible to infectious and neoplastic diseases and, potentially, to toxins. Island fox species-specific reference intervals will enable managers and veterinarians to better care for sick and injured foxes and will contribute to future population health monitoring.

Three pathogens in sympatric populations of pumas, bobcats, and domestic cats: implications for infectious disease transmission.

Anthropogenic landscape change can lead to increased opportunities for pathogen transmission between domestic and non-domestic animals. Pumas, bobcats, and domestic cats are sympatric in many areas of North America and share many of the same pathogens, some of which are zoonotic. We analyzed bobcat, puma, and feral domestic cat samples collected from targeted geographic areas. We examined exposure to three pathogens that are taxonomically diverse (bacterial, protozoal, viral), that incorporate multiple transmission strategies (vector-borne, environmental exposure/ingestion, and direct contact), and that vary in species-specificity. Bartonella spp., Feline Immunodeficiency Virus (FIV), and Toxoplasma gondii IgG were detected in all three species with mean respective prevalence as follows: puma 16%, 41% and 75%; bobcat 31%, 22% and 43%; domestic cat 45%, 10% and 1%. Bartonella spp. were highly prevalent among domestic cats in Southern California compared to other cohort groups. Feline Immunodeficiency Virus exposure was primarily associated with species and age, and was not influenced by geographic location. Pumas were more likely to be infected with FIV than bobcats, with domestic cats having the lowest infection rate. Toxoplasma gondii seroprevalence was high in both pumas and bobcats across all sites; in contrast, few domestic cats were seropositive, despite the fact that feral, free ranging domestic cats were targeted in this study. Interestingly, a directly transmitted species-specific disease (FIV) was not associated with geographic location, while exposure to indirectly transmitted diseases--vector-borne for Bartonella spp. and ingestion of oocysts via infected prey or environmental exposure for T. gondii--varied significantly by site. Pathogens transmitted by direct contact may be more dependent upon individual behaviors and intra-specific encounters. Future studies will integrate host density, as well as landscape features, to better understand the mechanisms driving disease exposure and to predict zones of cross-species pathogen transmission among wild and domestic felids.