Janet E Foley

University of California, Davis, Davis, California, United States

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Publications (120)276.07 Total impact

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    ABSTRACT: Equine infection with Corynebacterium pseudotuberculosis can manifest in several forms, including external or internal abscesses. The objective of this study was to phenotype clinical isolates of C. pseudotuberculosis and to investigate the relationship between lesion location and extent of lesions in the animals from which they were collected. One hundred and seventy-one C. pseudotuberculosis biovar equi isolates were collected from horses presenting to the University of California Veterinary Medical Teaching Hospital and two other sources in the period between September 1996 and December 2011. Bacterial isolates were grouped on the bases of biochemical characteristics and growth on brain heart infusion agar. Six phenotypes were identified: (1) large colonies that metabolized sucrose (n = 81); (2) large sucrose-negative colonies (n = 47); (3) medium sucrose-positive (n = 20); (4) medium sucrose-negative (n = 11); (5) small sucrose-positive (n = 7), and (6) small sucrose-negative (n = 5). Medical records corresponding to each isolate were accessed from the University's administrative computer system or from the submitting source in order to determine the anatomical site from which the isolate was collected (n = 171), as well as the extent of lesions (n = 164) in the patient. The relationship between phenotype, lesion location and extent of lesions was then investigated statistically. No significant relationship between strain and lesion location or extent of lesions was found. This suggests that phenotypic differences during in vitro culture does not account for external versus internal disease in horses. Further work to characterize strains genotypically and to identify determinants for bacterial virulence should be performed. Importantly, host and environmental factors should also be further investigated.
    The Veterinary Journal 05/2014; · 2.42 Impact Factor
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    ABSTRACT: Abstract From June to October 2010, 48 endangered riparian brush rabbits (Sylvilagus bachmani riparius) were trapped at a captive propagation site in central California with the intention of release into re-established habitats. During prerelease examinations, ticks and blood samples were collected for surveillance for Rickettsia spp., Anaplasma phagocytophilum, Borrelia burgdorferi, and Bartonella spp. Ticks were identified, and DNA was extracted for PCR analysis. Serology was performed to detect exposure to Rickettsia spp., B. burgdorferi, and A. phagocytophilum. DNA was extracted from blood samples and analyzed for A. phagocytophilum using PCR assays. Rabbit blood samples were also cultured for Bartonella spp. Haemaphysalis leporispalustris ticks were detected on all rabbits except one. A total of 375 ticks were collected, with 48% of the rabbits (23 rabbits) having a burden ranging from 0 to 5 ticks, 15% (seven rabbits) from 6 to 10 ticks, 25% (12 rabbits) from 11 to 15 ticks, and 12% (six rabbits) with >15 ticks. There was no evidence of B. burgdorferi or R. rickettsii in tick or rabbit samples. There was also no evidence of Bartonella spp. in the rabbit samples. Four tick samples and 14 rabbits were weakly PCR positive for A. phagocytophilum, and six rabbits were antibody positive for A. phagocytophilum. These results suggest that there may be little risk of these tick-borne diseases in riparian brush rabbits or to the people in contact with them.
    Journal of wildlife diseases 02/2014; · 1.27 Impact Factor
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    ABSTRACT: We investigated the involvement of birds in the ecology of the western black-legged tick, Ixodes pacificus, and its associated zoonotic bacteria, Borrelia burgdorferi and Anaplasma phagocytophilum, at two interior coast-range study sites in northern California. Anaplasma phagocytophilum, the agent of granulocytic anaplasmosis (GA), and B. burgdorferi s.s., the agent of Lyme disease (LD), are tick-borne pathogens that are well established in California. We screened blood and ticks from 349 individual birds in 48 species collected in 2011 and 2012 using pathogen-specific PCR. A total of 617 immature I. pacificus was collected with almost three times as many larvae than nymphs. There were 7.5 times more I. pacificus at the Napa County site compared to the Yolo County site. Two of 74 (3%) nymphal pools from an Oregon junco (Junco hyemalis) and a hermit thrush (Catharus guttatus) and 4 individual larvae (all from Oregon juncos) were PCR-positive for B. burgdorferi. Blood samples from a golden-crowned sparrow (Zonotrichia atricapilla) and a European starling (Sturnus vulgaris) were positive for A. phagocytophilum DNA at very low levels. Birds that forage on ground or bark and nest on the ground, as well as some migratory species, are at an increased risk for acquiring I. pacificus. Our findings show that birds contribute to the ecologies of LD and GA in California by serving as a blood-meal source, feeding and transporting immature I. pacificus, and sometimes as a source of Borrelia infection.
    Ticks and Tick-borne Diseases 01/2014; · 2.35 Impact Factor
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    ABSTRACT: The primary challenge to mountain lion population viability in California is habitat loss and fragmentation. These habitat impacts could enhance disease risk by increasing contact with domestic animals and by altering patterns of exposure to other wild felids. We performed a serologic survey for feline pathogens in California mountain lions (Puma concolor) using 490 samples from 45 counties collected from 1990 to 2008. Most mountain lions sampled were killed because of depredation or public safety concerns and 75% were adults. Pathogens detected by serosurvey in sampled mountain lions included feline panleukopenia virus (39.0%), feline calicivirus (33.0%), feline coronavirus (FCoV, 15.1%), feline herpesvirus (13.0%), heartworm (12.4%), feline leukemia virus (5.4%), and canine distemper virus (3%). An outbreak of heartworm exposure occurred from 1995 to 2003 and higher than expected levels of FCoV-antibody-positive mountain lions were observed from 2005 to 2008, with foci in southern Mendocino and eastern Lake counties. We show that the majority of mountain lions were exposed to feline pathogens and may be at risk of illness or fatality, particularly kittens. Combined with other stressors, such as ongoing habitat loss, infectious disease deserves recognition for potential negative impact on mountain lion health and population viability.
    Journal of wildlife diseases 04/2013; 49(2):279-93. · 1.27 Impact Factor
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    ABSTRACT: In July 2010, a horse from a rural farm (Farm A) in coastal Northern California was diagnosed with Salmonella Oranienburg infection following referral to a veterinary hospital for colic surgery. Environmental sampling to identify potential sources and persistence of Salmonella on the farm was conducted from August 2010 to March 2011. Salmonella was cultured using standard enrichment and selective plating. Pure colonies were confirmed by biochemical analysis, serotyped and compared by pulsed-field gel electrophoresis (PFGE) analysis. A total of 204 clinical and environmental samples at Farm A were analysed, and Salmonella spp. was isolated from six of eight (75%) horses, an asymptomatic pet dog, two of seven (28.6%) water samples from horse troughs, nine of 20 (45%) manure storage pile composites, 16 of 71 (22.5%) wild turkey faeces and four of 39 (10.3%) soil samples from the family's edible home garden. Well water and garden vegetable samples and horse faecal samples from a neighbouring ranch were negative. S. Oranienburg with a PFGE pattern indistinguishable from the horse clinical strain was found in all positive sample types on Farm A. The investigation illustrates the potential for widespread dissemination of Salmonella in a farm environment following equine infections. We speculate that a recent surge in the wild turkey population on the property could have introduced S. Oranienburg into the herd, although we cannot rule out the possibility wild turkeys were exposed on the farm or to other potential sources of Salmonella. Findings from the investigation indicated that raw horse manure applied as fertilizer was the most likely source of garden soil contamination. Viable S. Oranienburg persisted in garden soil for an estimated 210 days, which exceeds the 120-day standard between application and harvest currently required by the National Organic Program. The study underscores the need to educate the public about potential food safety hazards associated with using raw animal manure to fertilize edible home gardens.
    Zoonoses and Public Health 02/2013; · 2.09 Impact Factor
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    ABSTRACT: Identifying predators of threatened and endangered species is important for understanding and reducing the impacts of predation. Visible evidence collected from a carcass alone is often insufficient to accurately identify predator species. The DNA from the predator left on the carcass allows for a definitive identification of predator species associated with the carcass, but DNA can be difficult to isolate independently from the prey. We developed field collection and molecular protocols for amplifying canid and felid predator DNA from saliva on fisher (Martes pennanti) carcasses without amplifying fisher DNA itself. We tested the protocol on fisher carcasses suspected of having been killed by a bobcat (Lynx rufus), mountain lion (Puma concolor), coyote (Canis latrans), and domestic dog. We successfully amplified and sequenced DNA from these 4 predator species, confirming predation by them on fishers. We confirmed that these protocols could also identify other felid and canid predators of several other small North American carnivores. © 2013 The Wildlife Society.
    Wildlife Society Bulletin 01/2013; · 0.95 Impact Factor
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    ABSTRACT: In the summer and fall of 2010, a series of outdoor-housed rhesus macaques were diagnosed with tularemia. PCR analysis or positive culture confirmed 11 cases, and 9 additional animals with similar clinical signs responded to empiric antibiotic treatment. A serosurvey conducted in the 9 mo after the outbreak found 53% (43 of 81 macaques) seropositivity in the southern outdoor colony, which had an average population of 700 animals. A prospective survey of small mammal reservoirs and arthropod vectors was conducted during the late summer and fall of 2011. PCR analyses of tissues from all 135 mice, 18 ground squirrels, 1 rat, 3 raccoons, 2 cats, and 3 jackrabbits and their fleas were negative for DNA of Francisella tularensis. Conventional PCR evaluation of stored DNA from affected macaques identified the causative organism as F. tularensis subsp. holartica. DNA evaluated from historic cases of tularemia in nonhuman primates confirmed that the organism that infected the colony during the late 1980s likewise was F. tularensis subsp. holartica. The macaque tularemia epizootic of 2010 appears to have been an extreme example of the periodic resurgence of tularemia. No evidence of rodent disease was found in the immediate vicinity during the 2011 interepizootic period. The concurrent widespread seropositivity (53%) and low incidence of clinical disease (2.7%) in 2010 suggests that this strain of Francisella has low pathogenicity in macaques.
    Comparative medicine 01/2013; 63(2):183-90. · 1.12 Impact Factor
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    ABSTRACT: The aim of this study was to assess the prevalence and phylogenetic characterisation of Anaplasma phagocytophilum in ticks in three parks of the Emilia-Romagna region of northern Italy, an area in which no survey of this agent had previously been conducted. A total of 360 tick samples were analysed; 292 were sourced from the environment and 68 from animals and humans. Real-time polymerase chain reaction revealed that 33 tick samples (9.2%) were positive for A. phagocytophilum. Ixodes ricinus was the only species found positive from the samples retrieved from the environment and was the most commonly infected among ticks removed from hosts. Sequence analysis of the 23S-5S rRNA gene performed on 23 samples revealed six variant sequences that differed by only a few nucleotides when compared to the GenBank sequences from humans, horse and small mammals. Msp4 gene sequences obtained from 7 samples were compared to those described in ruminants, especially roe deer (Capreolus capreolus) and goat isolates from different countries. The results of this study provided evidence of the circulation of A. phagocytophilum in the sites studied and indicated the possible involvement of wild ruminants. Additional studies that extend the sampling areas, or cover different sites, would contribute to a better understanding of the ecology and disease dynamics of A. phagocytophilum in northern Italy and would provide valuable information on zoonotic risks.
    Veterinaria italiana 10/2012; 48(4):413-23. · 0.52 Impact Factor
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    ABSTRACT: Abstract Sera collected from 442 mountain lions in 48 California counties between the years of 1987 and 2010 were tested using immunofluorescence assays and agglutination tests for the presence of antibodies reactive to Yersinia pestis, Francisella tularensis, Bartonella henselae, Borrelia burgdorferi, and Anaplasma phagocytophilum antigens. Data were analyzed for spatial and temporal trends in seropositivity. Seroprevalences for B. burgdorferi (19.9%) and B. henselae (37.1%) were relatively high, with the highest exposure in the Central Coast region for B. henselae. B. henselae DNA amplified in mountain lion samples was genetically similar to human-derived Houston-1 and domestic cat-derived U4 B. henselae strains at the gltA and ftsZ loci. The statewide seroprevalences of Y. pestis (1.4%), F. tularensis (1.4%), and A. phagocytophilum (5.9%), were comparatively low. Sera from Y. pestis- and F. tularensis-seropositive mountain lions were primarily collected in the Eastern and Western Sierra Nevada, and samples reactive to Y. pestis antigen were collected exclusively from adult females. Adult age (≥2 years) was a risk factor for B. burgdorferi exposure. Over 70% of tested animals were killed on depredation permits, and therefore were active near areas with livestock and human residential communities. Surveillance of mountain lions for these bacterial vector-borne and zoonotic agents may be informative to public health authorities, and the data are useful for detecting enzootic and peridomestic pathogen transmission patterns, particularly in combination with molecular characterization of the infecting organisms.
    Vector borne and zoonotic diseases (Larchmont, N.Y.) 08/2012; · 2.61 Impact Factor
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    ABSTRACT: To evaluate disease progression in sheep experimentally inoculated with Anaplasma phagocytophilum and determine the Anaplasma spp seroprevalence in sheep in free-ranging flocks in the Sierra Nevada foothills and Oregon Coast Range. 10 mature ewes seronegative for Anaplasma spp and 251 sheep from 8 flocks. 10 ewes received 1 of 3 treatments: A phagocytophilum Webster strain (n = 4), A phagocytophilum MRK strain (4), or human promyelocytic leukemia cells (control treatment [2]). Sheep were monitored for signs of clinical disease, and blood samples were obtained for serologic and PCR assay evaluation intermittently for 48 days. From a subsample of sheep from each of 8 free-ranging flocks, blood samples were obtained to determine Anaplasma spp seroprevalence. Sheep inoculated with A phagocytophilum developed subclinical or mild disease, whereas sheep inoculated with the control treatment did not develop any signs of disease. Only 2 ewes seroconverted; both had received the MRK strain. Anaplasma-specific DNA was detected in blood samples from 1 sheep in the Webster strain-inoculated group and 3 sheep in the MRK strain-inoculated group. Sheep seropositive for Anaplasma spp were detected in 5 of 8 flocks, and flocks in the Sierra Nevada foothills had higher within-flock seroprevalence (22%) than did flocks in the Oregon Coast Range (6.4%). Infection with A phagocytophilum in mature sheep generally resulted in subclinical disease. Higher Anaplasma spp seroprevalence in sheep in the Sierra Nevada foothills corresponded to the geographic distribution of anaplasmosis reported for dogs, horses, and humans.
    American Journal of Veterinary Research 07/2012; 73(7):1029-34. · 1.35 Impact Factor
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    ABSTRACT: Urban and agricultural land use may increase the risk of disease transmission among wildlife, domestic animals, and humans as we share ever-shrinking and fragmented habitat. American badgers (Taxidae taxus), a species of special concern in California, USA, live in proximity to urban development and often share habitat with livestock and small peridomestic mammals. As such, they may be susceptible to pathogens commonly transmitted at this interface and to anticoagulant rodenticides used to control nuisance wildlife on agricultural lands. We evaluated free-ranging badgers in California for exposure to pathogens and anticoagulant rodenticides that pose a risk to wildlife, domestic animals, or public health. We found serologic evidence of badger exposure to Francisella tularensis, Toxoplasma gondii, Anaplasma phagocytophilum, canine distemper virus, and three Bartonella species: B. henselae, B. clarridgeiae, and B. vinsonii subsp. berkhoffii. Badger tissues contained anticoagulant rodenticides brodifacoum and bromadiolone, commonly used to control periurban rodent pests. These data provide a preliminary investigation of pathogen and toxicant exposure in the wild badger population.
    Journal of wildlife diseases 04/2012; 48(2):467-72. · 1.27 Impact Factor
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    ABSTRACT: The fungal pathogen Batrachochytrium dendrobatidis (Bd), which causes the disease chytridiomycosis, has been associated with declines and extinctions of montane amphibians worldwide. To gain insight into factors affecting its distribution and prevalence we focus on the amphibian community of the Klamath Mountains in northwest California. The Cascades frog (Rana cascadae), one of the most common amphibians in these mountains, experienced increased mortality as a result of Bd exposure in laboratory trials and has experienced recent, dramatic declines in other parts of California. We surveyed 112 sites in the Klamaths, all of which supported R. cascadae between 1999 and 2002, for amphibians and Bd to (1) determine the distribution of Bd, (2) evaluate changes in the distribution of R. cascadae, and (3) assess associations between potential biotic and abiotic drivers and Bd infection. Bd was widely distributed in the Klamath Mountains – we detected the pathogen at 64% of sites. R. cascadae was found at 79% of sites, and was often infected with Bd. These results suggest that Bd has not caused dramatic declines in R. cascadae in the Klamaths in recent years. Subadult R. cascadae had a higher Bd prevalence than other R. cascadae life stages (subadults: 36%, adults: 25%, metamorphs: 4%, larvae: 1%), and while the probability of infection decreased over the season for adults, it did not for subadults, suggesting that subadults may be more vulnerable to chytridiomycosis than other R. cascadae life stages. Bd prevalence in R. cascadae was highest early in the season at high-elevation sites, which may indicate that populations inhabiting high elevation sites may have a greater risk of being affected by chytridiomycosis. Three other common amphibian species also tested positive for Bd: Pacific chorus frog (Pseudacris regilla), western toad (Anaxyrus boreas), and rough-skinned newt (Taricha granulosa).
    Biological Conservation 12/2011; · 3.79 Impact Factor
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    ABSTRACT: Background/Question/Methods The fungal pathogen Batrachochytrium dendrobatidis (Bd) is associated with declines and extinctions of amphibians worldwide. In the western United States, frogs and toads in montane habitats have proven to be particularly susceptible. We focus on the effects of Bd on the Cascades frog (Rana cascadae) and other native amphibians in the mountains of northern California and ask: 1) What biotic and abiotic factors are associated with Bd prevalence? 2) How does Bd affect R. cascadae populations in the field? In 2008 and 2009, we conducted a survey for Bd throughout the California range of R. cascadae, sampling amphibians at over 110 sites. To provide detailed information on the effects of Bd on R. cascadae populations, we intensively sampled 15 populations throughout the 2009 and 2010 summer seasons. We individually marked a subset of the animals in each population, allowing us to follow infection dynamics at both the individual and the population level. Results/Conclusions The 2008-2009 survey indicated that Bd is widespread throughout the region, occurring in amphibians at 67% of all sites surveyed. The pathogen was detected in 26% of post-metamorphic R. cascadae and 1.5% larvae. In addition, the pathogen was detected in three other common amphibians – Western Toad (Bufo boreas), Pacific Chorus Frog (Pseudacris regilla), and Rough-skinned Newt (Taricha torosa). The survey also indicated that the prevalence of Bd in post-metamorphic R. cascadae was greatest at high-elevation sites early in the season. Furthermore, seasonal changes in prevalence depended on life stage, with prevalence increasing over the course of the season in subadults, while tending to decrease in adults. Preliminary results from intensively-sampled populations suggest that declining populations have low proportions of juveniles and subadults relative to stable or growing populations. We suggest that younger, smaller individuals are less effective at clearing the pathogen, and are therefore more susceptible to the disease that it causes, leading to low recruitment and population declines.
    96th ESA Annual Convention 2011; 08/2011
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    ABSTRACT: This study was carried out to compare different diagnostic techniques to reveal the presence of piroplasms in asymptomatic cattle kept at pasture. Nineteen blood samples were collected from animals of two different areas of Emilia Romagna Region of Italy and processed for microscopic observation, PCR, serological test (IFAT) for Babesia bovis and Babesia bigemina antibodies and in vitro cultivation. The cultures were performed on both bovine and ovine erythrocytes. Seventeen blood smears (89%) were positive for piroplasms, while PCR was positive on 18 samples (95%). DNA sequencing of 18S rRNA identified the piroplasms as Theileria spp. In vitro cultures were successful for 6 samples (32%) cultured on bovine blood and subsequent identified these as Babesia major by PCR. On IFAT analyses of 16 samples, 36.8% resulted positive for B. bovis and 31.6% positive for B. bigemina. These results show, in the same animals, the co-infection with Babesia spp. and Theileria spp.; the detection of B. major was possible only using the in vitro cultures.
    Veterinary Parasitology 07/2011; 183(3-4):364-8. · 2.38 Impact Factor
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    Janet E Foley, Nathan C Nieto
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    ABSTRACT: The redwood chipmunk contributes to the maintenance of tick-borne diseases in northern California. The range of redwood chipmunks overlaps that of western black-legged ticks and tick-borne disease, including granulocytic anaplasmosis and Lyme borreliosis. Chipmunks have high Anaplasma phagocytophilum PCR- and seroprevalence, are infested with a diversity of Ixodes spp. ticks, and are reservoir competent for Borrelia burgdorferi. We hypothesized that chipmunks could maintain tick-borne disease on the forest floor while also potentially bridging infection to arboreal sciurids as well. We used radio-telemetry to evaluate chipmunk movement and use of trees, characterized burrows, described prevalence of tick-borne disease, and identified ticks on these chipmunks. A total of 192 chipmunks from Hendy Woods, Mendocino County, California, USA, was evaluated between November 2005 and April 2009. The mean density was 2.26-5.8 chipmunks/ha. The longest detected life span was 3 years. Female weights ranged from 80-120 g and males from 80-180 g. The A. phagocytophilum and Borrelia spp. seroprevalence was 21.4% and 24.7%, respectively, and PCR prevalence for these pathogens was 10.6% and 0%, respectively. Ixodes spp. ticks included I. angustus, I. ochotonae, I. pacificus, and I. spinipalpis. The mean infestation level was 0.92 ticks/chipmunk. Based on telemetry of 11 chipmunks, the greatest distance traveled ranged from 0.14-0.63 km for females and 0.1-1.26 km for males. Areas occupied by chipmunks ranged from 0.005-0.24 km(2) for females and 0.006-0.73 km(2) for males. On 3 occasions, chipmunks were found in trees. Burrows were identified under a moss-covered redwood log, deep under a live redwood tree, under a Douglas fir log, in a clump of huckleberry, in a root collection from an overturned Douglas fir tree, and in a cluster of exposed huckleberry roots. The biology of the redwood chipmunk has multiple features that allow it to be an important reservoir host for tick-borne disease in northwestern California.
    Ticks and Tick-borne Diseases 06/2011; 2(2):88-93. · 2.35 Impact Factor
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    ABSTRACT: Granulocytic anaplasmosis (GA) is a tick-borne emerging infectious disease caused by the bacterium Anaplasma phagocytophilum. From fall 2005 to spring 2007, A. phagocytophilum infection prevalence in small mammals and tick abundance were monitored at 4 study sites in coastal California. The abundance of different life stages of questing Ixodes pacificus ticks fluctuated seasonally with the number of adults peaking December to February, nymphs peaking May to July, and larvae peaking April to June. Numerous Ixodes tick species were found attached to dusky-footed woodrats (Neotoma fuscipes), chimunks (Tamias spp.), and deer mice (Peromyscus maniculatus); however, attached tick larvae on all 3 rodent species were primarily I. pacificus, attached nymphs were primarily I. angustus, and adults were either I. ochotonae, I. spinipalpis, or I. woodi. A. phagocytophilum DNA was detected by PCR in 2.2% (n=275, 95% C.I.=0.09-4.9) of sampled ticks. The overall A. phagocytophilum seroprevalence among small mammals was 7.4% (n=654, 95% C.I.=5.5-9.7) while 7.2% (n=125, 95% C.I.=3.5-13.4) of the animals were found to be PCR-positive. Seropositive animals included woodrats, chipmunks, and deer mice, although only woodrats and chipmunks had PCR-detectable infections. Seroprevalence varied temporally among species with the majority of exposed deer mice detected in fall 2006 and the majority of exposed woodrats and chipmunks identified in spring 2007. This study highlights the importance of multiple-year monitoring of both vectors and wildlife hosts in order to better understand the complex ecology of A. phagocytophilum and other related tick-borne disease agents.
    Ticks and Tick-borne Diseases 06/2011; 2(2):81-7. · 2.35 Impact Factor
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    ABSTRACT: Anthropogenic environmental change is often implicated in the emergence of new zoonoses from wildlife; however, there is little mechanistic understanding of these causal links. Here, we examine the transmission dynamics of an emerging zoonotic paramyxovirus, Hendra virus (HeV), in its endemic host, Australian Pteropus bats (fruit bats or flying foxes). HeV is a biosecurity level 4 (BSL-4) pathogen, with a high case-fatality rate in humans and horses. With models parametrized from field and laboratory data, we explore a set of probable contributory mechanisms that explain the spatial and temporal pattern of HeV emergence; including urban habituation and decreased migration-two widely observed changes in flying fox ecology that result from anthropogenic transformation of bat habitat in Australia. Urban habituation increases the number of flying foxes in contact with human and domestic animal populations, and our models suggest that, in addition, decreased bat migratory behaviour could lead to a decline in population immunity, giving rise to more intense outbreaks after local viral reintroduction. Ten of the 14 known HeV outbreaks occurred near urbanized or sedentary flying fox populations, supporting these predictions. We also demonstrate that by incorporating waning maternal immunity into our models, the peak modelled prevalence coincides with the peak annual spill-over hazard for HeV. These results provide the first detailed mechanistic framework for understanding the sporadic temporal pattern of HeV emergence, and of the urban/peri-urban distribution of HeV outbreaks in horses and people.
    Proceedings of the Royal Society B: Biological Sciences 05/2011; 278(1725):3703-12. · 5.68 Impact Factor
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    ABSTRACT: Ticks, fleas, and vector-borne pathogens were surveyed in diverse small mammals in Yosemite National Park, California, from 2005 to 2007. A total of 450 unique captures of small mammals was collected during a 3-yr period and yielded 16 species of fleas and 10 species of ticks, including known vectors of Anaplasma phagocytophilum and Borrelia burgdorferi and plague. Serology was performed for A. phagocytophilum, spotted fever group Rickettsia spp., B. burgdorferi, and Yersinia pestis. A. phagocytophilum exposure was identified in 12.1% of all wild small mammals tested, with seropositive animals in 10 species, notably Belding's ground squirrels (Spermophilus beldingi), jumping mice (Zapus princeps), and voles (Microtus sp.). Spotted fever group Rickettsia spp. exposure was detected in 13.9% of all small mammals tested, with seropositive animals in eight species. Additionally, 37.0% of rodents in five species tested were seropositive for B. burgdorferi. No individuals were seropositive for Y. pestis. No animals were polymerase chain reaction positive for any pathogen tested. These results provide baseline data for future research and prediction of emerging vector-borne disease in Yosemite National Park, as well as adding to the known ranges and host species for tick and fleas in California.
    Journal of Medical Entomology 01/2011; 48(1):101-10. · 1.86 Impact Factor
  • Janet E. Foley
    Entomological Society of America Annual Meeting 2010; 12/2010
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    ABSTRACT: Wildlife managers often need to assess the current health status of wildlife communities before implementation of management actions involving surveillance, reintroductions, or translocations. We estimated the sensitivity and specificity of a commercially available domestic canine rapid diagnostic antigen test for canine parvovirus and a rapid enzyme-linked immunosorbent assay for the detection of antibodies toward Anaplasma phagocytophilum on populations of fishers (Martes pennanti) and sympatric gray foxes (Urocyon cinereoargenteus). Eighty-two fecal samples from 66 fishers and 16 gray foxes were tested with both SNAP((R)) PARVO rapid diagnostic test (RDT) and a nested polymerase chain reaction (PCR). Whole blood samples from 23 fishers and 53 gray foxes were tested with both SNAP 4Dx RDT and immunofluorescence assays (IFAs). The SNAP PARVO RDT detected no parvovirus, whereas PCR detected the virus in 17 samples. Eleven samples were positive using the SNAP 4Dx RDT, whereas 46 samples tested by IFA were positive for A. phagocytophilum. Both RDTs had low sensitivity and poor test agreement. These findings clearly demonstrate the importance of validating RDTs developed for domesticated animals before using them for wildlife populations.
    Journal of wildlife diseases 07/2010; 46(3):966-70. · 1.27 Impact Factor

Publication Stats

2k Citations
276.07 Total Impact Points


  • 1997–2014
    • University of California, Davis
      • • School of Veterinary Medicine
      • • Department of Wildlife, Fish and Conservation Biology
      • • Department of Veterinary Medicine and Epidemiology
      Davis, California, United States
  • 2013
    • Wisconsin National Primate Research Center
      Madison, Wisconsin, United States
  • 2010
    • Integral Ecology Research Center
      Blue Lake, California, United States
  • 2008
    • Seoul National University
      • College of Veterinary Medicine
      Seoul, Seoul, South Korea
  • 2001–2007
    • CSU Mentor
      Long Beach, California, United States
  • 2006
    • University of Florida
      Gainesville, Florida, United States