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Some pathogens sustain transmission in multiple different host species, but how this epidemiologically important feat is achieved remains enigmatic. Sarcoptes scabiei is among the most host generalist and successful of mammalian parasites. We synthesize pathogen and host traits that mediate sustained transmission and present cases illustrating three transmission mechanisms (direct, indirect, and combined). The pathogen traits that explain the success of S. scabiei include immune response modulation, on-host movement capacity, off-host seeking behaviors, and environmental persistence. Sociality and host density appear to be key for hosts in which direct transmission dominates, whereas in solitary hosts, the use of shared environments is important for indirect transmission. In social den-using species, combined direct and indirect transmission appears likely. Empirical research rarely considers the mechanisms enabling S. scabiei to become endemic in host species—more often focusing on outbreaks. Our review may illuminate parasites’ adaptation strategies to sustain transmission through varied mechanisms across host species.

Mites from the family Halarachnidae Oudemans 1906 are obligate endoparasites that colonize the respiratory tracts of free-living and captive marine mammals. Infestations can range from mild to severe and result in respiratory tract irritation or impairment. Nasopulmonary acariasis was determined to be a contributing cause of death among several southern sea otters Enhydra lutris nereis Merriam 1904 in a longitudinal study of otter mortality, and proximity to Pacific harbor seals Phoca vitulina richardii Gray 1864 was a significant risk factor for sea otter infestation. Beyond scattered opportunistic reports, each halarachnid mite species' affinity for particular hosts and the extent of mite transmission between host species is poorly understood. We investigated the identity and prevalence of nasopulmonary mites from Pacific harbor seals, California sea lions Zalophus californianus Lesson 1828, northern elephant seals Mirounga angustirostris Gill 1866, northern fur seals Callorhinus ursinus Linnaeus 1758, and Guadalupe fur seals Arctocephalus philippii townsendi Merriam 1897 to complement published nasopulmonary mite findings from sympatric southern sea otters during a comparable timeframe. Halarachnid mite infestation was common among California sea lions (74.1%), northern fur seals (73.3%), and northern elephant seals (46.6%), but was less common among harbor seals (18.7%) and Guadalupe fur seals (8.8%). Observed host-mite relationships suggest a distinct host specificity, with genus Orthohalarachne infesting otariids, and genus Halarachne infesting phocids and lutrinids along the California coast. Harbor seals and southern sea otters were the primary hosts of H. halichoeri, but one nothern elephant seal was infested with both H. miroungae and a single H. halichoeri. We also present the first high-resolution SEM images for H. miroungae and O. attenuata and possible evidence for a new host record for H. halichoeri., Graphical abstract Image 1, Highlights • Host-mite relationships suggest a distinct host specificity among halarachnid genera. • Halarachnid mite infestation is common among Pacific pinnipeds. • Harbor seals and southern sea otters were the primary hosts of H. halichoeri. • 16S sequences of mites from Halarachne and Orthohalarachne were generated. • Scanning electron micrographs of H. miroungae and O. attenuata were generated.

Over one hundred cases of human rickettsiosis, many fatal, are reported annually across the US-Mexico transboundary region, representing a likely undercount. Although cases are often attributed to Rickettsia rickettsii, the agent of Rocky Mountain spotted fever, multiple other Rickettsia pathogens are present in North America. We conducted multiple-host surveillance of domestic, synanthropic, and sylvatic mammals and their ectoparasites to investigate the ecology of Rickettsia species in this region. A total of 499 mammals, including 83 dogs, 23 wild carnivores, five lagomorphs, and 388 rodents were sampled, and 413 fleas and 447 ticks belonging to 15 and 4 species, respectively, were collected during 2017 and 2018. We detected Rickettsia spp. DNA in one blood sample of coyote (Canis latrans), 11 ear tissues of rodents (10.6%), and 79 ectoparasites (9.5%). Of the 64 Rickettsia-positive fleas, 54 were Echidnophaga gallinacea and 10 were Pulex simulans, while of the 15 ticks, 11 were Rhipicephalus sanguineus s.l. and four Ixodes pacificus. The DNA sequence alignment of gltA and ompB regions revealed one and ten genetic variants of Rickettsia spp., respectively. These variants were clustered in clades of zoonotic species (R. felis, R. massiliae, R. parkeri, R. rickettsii, and R. typhi) and organisms of unknown pathogenic significance (R. asembonensis and Candidatus Rickettsia tarasevichiae). The finding of a coyote infected with R. rickettsii and the multiple zoonotic SFG rickettsial agents in the study area suggest that: 1) wild canids could serve as an amplifying host for RMSF, an alternate host for Rh. sanguineus s.l. ticks, and a means to spread infection and ticks over large areas; and 2) at least some of the human rickettsiosis cases attributed to R. rickettsii could be caused by other Rickettsia species. This study strongly supports the importance of multiple-host and vector eco-epidemiological studies and the One Health approach to better understand disease in a RMSF-epidemic region.

Timber harvest may impact tick-borne disease by affecting small mammal and tick community structures. We assessed tick and small mammal populations in older second-growth redwood (Sequoia sempervirens (D. Don) Endl) habitat at two harvested sites in Santa Cruz County, California, where local risk of tick-borne disease is high and determined the prevalence of tick-borne pathogens in ticks. After single-tree removal harvest in 2014, there was a modest reduction in canopy, primarily toward the end of the study. Harvested sites showed strong reductions in California mouse (Peromyscus californicus, (Gambel)) captures 2-yr after harvest, resolving such that treatments and controls were comparable by the end of the study. Following harvest, treated sites experienced a transient decreased tick infestation while control plots experienced an increase. Ixodes angustus (Neumann) infestation probability on harvested plots decreased immediately after harvest, increasing with time but remaining lower than control plots, whereas I. pacificus (Cooley and Kohls) prevalence was higher shortly after the harvest on harvested plots, and continued to increase. Mean abundance of ticks on vegetation increased on control plots. We detected Borrelia burgdorferi ((Johnson et al.) Baranton) and Anaplasma phagocytophilum ((Foggie 1949) Dumler) in 3.8 and 3.1% of ticks on rodents, but no differences were associated with harvest. Impacts of forest harvest on tick-borne disease depend on removal practice and intensity, whether or not hosts are habitat specialists, and whether or not ticks are host specialists.

OBJECTIVE To perform a cross-sectional survey to estimate prevalence of and potential risk factors for Leptospira spp infection and exposure in peri-urban wildlife throughout California. ANIMALS 723 animals representing 12 wildlife species. PROCEDURES Blood and urine samples were obtained from wildlife in California from 2007 to 2017. Live animals were captured in humane traps, anesthetized, and released. Carcasses were donated by wildlife services and necropsied for urine, blood, and kidney tissue samples. Samples were tested for antibodies against 6 serovars of Leptospira spp with a microscopic agglutination test and for pathogenic Leptospira spp DNA with a real-time PCR assay targeting the LipL32 gene. Potential risk factors for Leptospira spp exposure were assessed by logistic regression. Genetic relatedness of Leptospira spp were assessed with DNA sequencing of the rrs2 gene and multiple locus sequence analysis. RESULTS Statewide Leptospira spp seroprevalence was 39.1%, and prevalence of positive PCR assay results for Leptospira spp DNA was 23.0%. Risk factors for Leptospira spp exposure included being an adult, being from northern California, and being a western gray squirrel, coyote, striped skunk, raccoon, gray fox, or mountain lion. Antibodies against serovar Pomona predominated in most species, followed by serovar Copenhageni. Complete rrs2 sequences were identified as Leptospira interrogans and multiple locus sequence type analysis revealed sequence type 140. CONCLUSIONS AND CLINICAL RELEVANCE Pathogenic Leptospira spp appeared to be common and widespread among peri-urban wildlife in California. Our data highlight the potential for exposure to infectious disease for both humans and domestic animals at the urban-wildland interface.

Tickborne diseases are an increasing public health threat in the United States. Prevention and diagnosis of tickborne diseases are improved by access to current and accurate information on where medically important ticks and their associated human and veterinary pathogens are present, their local abundance or prevalence, and when ticks are actively seeking hosts. The true extent of tick and tickborne pathogen expansion is poorly defined, in part because of a lack of nationally standardized tick surveillance. We surveyed 140 vector-borne disease professionals working in state, county, and local public health and vector control agencies to assess their 1) tick surveillance program objectives, 2) pathogen testing methods, 3) tick control practices, 4) data communication strategies, and 5) barriers to program development and operation. Fewer than half of respondents reported that their jurisdiction was engaged in routine, active tick surveillance, but nearly two-thirds reported engaging in passive tick surveillance. Detection of tick presence was the most commonly stated current surveillance objective (76.2%). Most of the programs currently supporting tick pathogen testing were in the Northeast (70.8%), Upper and Central Midwest (64.3%), and the West (71.4%) regions. The most common pathogens screened for were Rickettsia spp. (Rickettsiales: Rickettsiaceae) and bacterial and viral agents transmitted by Ixodes (Acari: Ixodidae) ticks. Only 12% of respondents indicated their jurisdiction directly conducts or otherwise financially supports tick control. Responses indicated that their ability to expand the capacity of tick surveillance and control programs was impeded by inconsistent funding, limited infrastructure, guidance on best practices, and institutional capacity to perform these functions.

Leptospirosis is a globally important, fatal disease of humans, and over 160 species of animals are associated with more than 250 bacterial serovars in 64 species, but its ecology varies regionally...

The sensu lato (s.l.) complexes of Borrelia burgdorferi and Anaplasma phagocytophilum include pathogenic genospecies each with distinct ecologies in northern California, yet, most work conflates the genospecies of each pathogen into one sensu lato species. Detailed understanding of the differences in geographic distributions and ecology among genospecies is lacking. We aimed to evaluate whether two B. burgdorferi and two A. phagocytophilum genospecies in high-risk locations in coastal northern California were spatially clustered and if presence of a particular genospecies was associated with geographical site, host species, or other demographic or ecological variables. DNA sequencing was performed to differentiate genospecies of Borreliae and Anaplasma from PCR-positive dusky-footed woodrats (Neotoma fuscipes) and sciurids (chipmunks, Tamias spp., and Douglas squirrels, Tamiasciurus douglasii) at four sites in northwestern California. Logistic regression was performed to assess associations of genospecies with the predictor variables host species, host sex, site, season, and year. Spatial clustering was assessed using a Poisson spatial scan statistic in SaTScan. Host species was a significant predictor for Borrelia bissettiae, B. burgdorferi sensu stricto (s.s.), A. phagocytophilum s.s., and the DU1 Anaplasma genospecies. Woodrats were significantly more likely to be PCR-positive for B. bissettiae and A. phagocytophilum DU1 genospecies, while A. phagocytophilum s.s. and B. burgdorferi s.s. were significantly associated with sciurids. We report a single Borrelia lanei in an Allen's chipmunk (Tamias senex) from the Hoopa Valley Tribal Reservation. A significant spatial cluster of A. phagocytophilum s.s. was detected at Hendy Woods State Park in Mendocino County. These results highlight the need to better understand genospecies partitioning according to host species to further assess human risks, aid in future surveillance, and inform targeted research.

Disease may limit recovery of endangered species. We surveyed parasites in the federally endangered salt marsh harvest mouse (SMHM; Reithrodontomys raviventris halicoetes) and sympatric rodents in Suisun Marsh (Solano County, California, USA) from April 2018 through March 2019. We investigated individual SMHM risk factors (age, sex, reproductive status, and body condition) for infection and relationships among the estimated parasite prevalence and season and habitat management (natural tidal habitats versus diked, nontidal habitats). We captured 625 individual rodents, including 439 SMHM, and tested these for infection with Bartonella spp., Borrelia spp., Rickettsia spp., Francisella tularensis, Leptospira spp., Cryptosporidium spp., Giardia spp., and Toxoplasma gondii by PCR. Over one-third (34.6%, confidence interval [CI], 30.2%-39.3%) of SMHM tested positive for at least one parasite. Four percent (CI, 2.8%-6.3%) of SMHM were infected with F. tularensis holarctica, a virulent bacterium that causes mortality in rodents shortly after infection. Additionally, we detected three species of Bartonella (B. henselae, B. rochalimae, B. vinsonii arupensis), Leptospira borgpetersenii serovar Ballum, Cryptosporidium sp. (deer mouse [Peromyscus maniculatus] genotype), Cryptosporidium parvum, Giardia intestinalis, and an unidentified Borrelia sp. The only parasite that was associated with habitat management was Bartonella spp., which was more prevalent in diked than tidal areas. Male SMHM were more likely to be parasitized than females, and individuals in modestly poor body condition were most likely to be infected with Bartonella spp. The estimated sample prevalence of multiple parasites varied by season and by host species. This is the first major parasite assessment in a long-endangered species, and these results will assist managers to incorporate parasitic disease into recovery planning and provide a critical baseline for future investigations, including how climatically induced habitat and species composition changes could alter disease dynamics.

As the world's most ubiquitous carnivore, domestic dogs maintain unique proximity to human populations. Partly because dogs potentially serve as hosts of zoonotic diseases, determinants of canine health are increasingly the focus of interdisciplinary research. Emerging perspectives suggest that dogs' health may vary as a function of their owners' wealth and financial resources, a correlation that could potentially inform public health programs and conservation efforts. The objective of this study was to evaluate associations between household wealth and the health of domestic dogs (n = 208) among indigenous Mayangna communities in the Bosawás Biosphere Reserve, Nicaragua. The dogs were evaluated using serum biochemistry, complete blood count, and physical exam findings. Using these data, a principal components analysis (PCA) determined the presence of four "syndromes": 1) decreased body condition score (BCS) & hypoalbuminemia; 2) lymphocytosis & eosinophilia; 3) segmented neutrophilia; and 4) lymphadenopathy, tick infestation, & hyperglobulinemia. An inventory of possessions indexed household wealth. For all four syndromes, household wealth was a weak and uninformative predictor of the dogs' health. The few differences seen among dogs from households with different degrees of wealth likely reflect that nearly all dogs had marginal health and all households were relatively poor. Results from this study imply that owners' wealth may have diverse effects on canine health in rural settings.

Ixodes (Ixodes) mojavensis, n. sp. (Acari: Ixodidae), is described from all parasitic stages collected from the endangered vole Microtus californicus scirpensis Bailey, 1900 (Rodentia: Cricetidae), Mus musculus L. 1758 (Rodentia: Muridae), and Reithrodontomys megalotis (Baird; 1857) (Rodentia: Cricetidae) in the Amargosa Valley of California. When first collected in 2014, this tick was tentatively identified as Ixodes minor Neumann, 1902 because the nucleotide similarity between its 16S rDNA sequence and a homologous GenBank sequence from an I. minor from the eastern U.S. was 99.51%. Nevertheless, adults of I. mojavensis differ morphologically from I. minor by hypostomal dentition, absence of a spur on palpal segment I, and punctation patterns; nymphs by the shapes of basis capituli, auriculae, cervical grooves and external files of hypostomal denticles; and larvae by the length of idiosomal setae and hypostomal dentition. DNA sequencing of fragments of 4 different genes, 12S rDNA, 16S rDNA, cytochrome c oxidase subunit I (COI), and intergenic transcribed spacer 2 (ITS2) of I. mojavensis and of closely related species of Ixodes shows that the mitochondrial gene sequences of the new tick species are almost identical to the I. minor homologous genes. Phylogenetically, the two species do not cluster in mutually exclusive monophyletic clades. However, ITS2 sequences of I. mojavensis and I. minor diverge deeply (≥ 5.74% maximum likelihood divergence) and are as different as homologous genes from other recognized species. The discrepancy between the two sets of genes is suggestive of past mitochondrial introgression or incomplete mitochondrial lineage sorting.

Background Fire strongly affects animals’ behavior, population dynamics, and environmental surroundings, which in turn are likely to affect their immune systems and exposure to pathogens. However, little work has yet been conducted on the effects of wildfires on wildlife disease. This research gap is rapidly growing in importance because wildfires are becoming globally more common and more severe, with unknown impacts on wildlife disease and unclear implications for livestock and human health in the future. Results Here, we discussed how wildfires could influence susceptibility and exposure to infection in wild animals, and the potential consequences for ecology and public health. In our framework, we outlined how habitat loss and degradation caused by fire affect animals’ immune defenses, and how behavioral and demographic responses to fire affect pathogen exposure, spread, and maintenance. We identified relative unknowns that might influence disease dynamics in unpredictable ways (e.g., through altered community composition and effects on free-living parasites). Finally, we discussed avenues for future investigations of fire-disease links. Conclusions We hope that this review will stimulate much-needed research on the role of wildfire in influencing wildlife disease, providing an important source of information on disease dynamics in the wake of future wildfires and other natural disasters, and encouraging further integration of the fields of fire and disease ecology.

There is a paucity of data on human exposure to tick-borne pathogens in the western United States. This study reports prevalence of antibodies against three clinically important tick-borne...

Parvoviruses in the genera Bocaparvovirus (HBoV), Erythroparvovirus (B19) and Tetraparvovirus (PARV4) are the only autonomous parvoviruses known to be associated with human and non‐human primates based on studies and clinical cases in humans worldwide and non‐human primates in Asia and Africa. Here, the presence of these agents with pathogenic potential was assessed by PCR in blood and faeces from 55 howler monkeys, 112 white‐face monkeys, 3 squirrel monkeys and 127 spider monkeys in Costa Rica and El Salvador. Overall, 3.7% (11/297) of the monkeys had HboV DNA, 0.67% (2/297) had B19 DNA, and 14.1% (42/297) had PARV4 DNA, representing the first detection of these viruses in New World Primates (NWP). Sex was significantly associated with the presence of HBoV, males having greater risk up to nine times compared with females. Captivity was associated with increased prevalence for PARV4 and when all viruses were analysed together. This study provides compelling molecular evidence of parvoviruses in NWPs and underscores the importance of future research aimed at understanding how these viruses behave in natural environments of the Neotropics and what variables may favour their presence and transmission. UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones en Productos Naturales (CIPRONA) UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biología UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Química

Halarachne sp. nasal mites infest harbor seals (Phoca vitulina) and southern sea otters (Enhydra lutris nereis) in California, but little is known about the pathophysiology of these infestations, or risk factors for exposure. To investigate these questions, a retrospective case-control study was performed using necropsy data from 70 mite-infested sea otters, and 144 non-infested controls. Case records for sea otters examined by pathologists from February 1999 through May 2015 were examined to assess risk factors for infestation, and lesions associated with nasopulmonary acariasis. Animals with a history of captive care within 10 days of death or carcass recovery were 3.2 times more likely to be infested with nasopulmonary mites than those with no history of recent rehabilitation. Sea otters stranding within 1 km of Elkhorn Slough in Monterey Bay were 4.9 times more likely to be infested with nasal mites than other areas; this site is characterized by high sea otter contact with sympatric harbor seals (a common host for Halarachne sp.), and a comparatively large population of rehabilitated and released sea otters. Aged adult otters were 9.4 times more likely to be infested than younger animals, and sea otters with nasopulmonary acariasis were 14.2 times more likely to have upper respiratory inflammation than un-infested animals. Additional findings in otters with nasopulmonary acariasis included lower respiratory tract bacterial infections, presence of medium-sized and/or fresh nose wounds at necropsy (indicators of recent face-to-face interaction between otters during copulation or fighting), and turbinate bone erosion. Our findings, although preliminary, suggest that captive rehabilitation and close contact with harbor seals could facilitate nasopulmonary mite transmission to sea otters. We also identified a high-risk zone for nasopulmonary acariasis in sea otters. We also provide preliminary data to suggest that nasopulmonary mite infestations can cause significant respiratory pathology in sea otters. Keywords: Enhydra lutris, Epidemiology, Halarachne sp., Nasal (nasopulmonary) mite, Risk factor, Sea otter

The genus Amdoparvovirus includes the newly discovered skunk amdoparvovirus and the well-characterized Aleutian disease virus which causes significant health impacts in farmed mink worldwide. In 2010-2013, an outbreak of fatal amdoparvovirus-associated disease was documented in free-ranging striped skunks (Mephitis mephitis) from the San Francisco Bay Area of California. To characterize the geographic distribution, earliest occurrence and abundance of this virus, as well as possible impacts on sympatric mustelids of conservation concern, we tested blood samples from skunks throughout California and fishers (Pekania pennanti) from northern California for amdoparvovirus DNA. Amdoparvovirus DNA was detected in 64.8% of sampled skunks (140/216), and test-positive skunks were distributed widely throughout the state, from as far north as Humboldt County and south to San Diego County. The first test-positive skunks were detected from 2004, prior to the 2010-2013 outbreak. No significant spatial or temporal clustering of infection was detected. Although healthy and clinically ill animals tested positive for amdoparvovirus DNA, histopathologic evaluation of a subset from clinically ill skunks indicated that positive PCR results were associated with pneumonia as well as there being more than one inflammatory type lesion. None of 38 fishers were PCR-positive. Given the widespread geographic distribution and lack of a clear epizootic centre, our results suggest the presence of an endemic skunk-associated amdoparvovirus strain or species. However, if the virus is not host-specific, skunks' ubiquitous presence across rural and urban habitats may pose a risk to susceptible domestic and wild species including mustelids of conservation concern such as fishers and Pacific martens (Martes caurina).

An epidemic of Rocky Mountain spotted fever (RMSF) is ongoing in Mexicali, México. We visited 100 neighborhoods with diagnosed human cases and 100 control neighborhoods to evaluate knowledge of the epidemic; obtain data on the spatial distribution of dogs, canine seroprevalence and active infection, tick infestations, and presence of rickettsial DNA in ticks; and evaluate risk factors for human cases, seropositivity, and tick infestation within an unbiased study design. The majority (80%) of residents had heard of RMSF, but only 48% used acaricides in the home or on dogs. Case neighborhoods and those with high canine seroprevalence tended to be on the city periphery or in the agricultural valley. No dogs were polymerase chain reaction (PCR) positive for Rickettsia rickettsii, and the overall seroprevalence was 65% (titers from 64 to 1,024). PCR prevalence in ticks was 0.70%, confirmed by DNA sequencing as R. rickettsii; neighborhood prevalence ranged from 0.7% to 6.1%. Twelve percent of dogs had high tick burdens, and all ticks were Rhipicephalus sanguineus. Epidemiologically significant risk factors were ground covering for a neighborhood having a human case; dogs having poor body condition and weighing < 10 kg for canine seropositivity; dogs living at the home for the number of ticks in the environment; and being near canals, having trash on the patio, and a dog being thin for tick burdens on dogs. A One Health approach is crucial to understanding RMSF and brown dog ticks.

Sarcoptic mange is a skin disease caused by the mite Sarcoptes scabiei that can devastate populations of wild species. S. scabiei can survive off-host and remain infective for specific periods. In den-dwelling species, dislodged mites could be protected from the environmental conditions that impair their survival thus supporting pathogen transmission. To assess the potential role of dens in the spread, establishment, and persistence of sarcoptic mange in a population of hosts, we constructed an agent-based model of the endangered San Joaquin kit fox (SJKF; Vulpes macrotis mutica) population in Bakersfield, California, that explicitly considered the denning ecology and behavior of this species. We focused on this SJKF urban population because of their vulnerability and because a sarcoptic mange epizootic is currently ongoing. Further, SJKF is a social species that lives in family groups year-round and contact between individuals from different family groups is rare, but they will occupy the same dens intermittently. If mites remain infective in dens, they could support intra-family disease transmission via direct (den sharing) and indirect (contaminated den) contact, but also inter-family transmission if susceptible individuals from different families occupy contaminated dens. Simulations showed that den-associated transmission significantly increases the chances for the mite to spread, to establish and to persist. These findings hold for different within-den S. scabiei off-host survival periods assessed. Managers dealing with S. scabiei in this species as well as in other den-dwelling species should consider den-associated transmission as they could be targeted as part of the control strategies against this mite. Keywords: Sarcoptic mange, Sarcoptes scabiei, Den, Burrow, Indirect transmission, San Joaquin Kit Fox

Rhipicephalus sanguineus is a species complex of ticks that vector disease worldwide. Feeding primarily on dogs, members of the complex also feed incidentally on humans, potentially transmitting disease agents such as Rickettsia rickettsii, Rickettsia conorii, and Ehrlichia species. There are two genetic Rh. sanguineus lineages in North America, designated as the temperate and tropical lineages, which had occurred in discrete locations, although there is now range overlap in parts of California and Arizona. Rh. sanguineus in Europe are reportedly more aggressive toward humans during hot weather, increasing the risk of pathogen transmission to humans. The aim of this study was to assess the impact of hot weather on choice between humans and dog hosts among tropical and temperate lineage Rh. sanguineus individuals. Ticks in a two-choice olfactometer migrated toward a dog or human in trials at room (23.5°C) or high temperature (38°C). At 38°C, 2.5 times more tropical lineage adults chose humans compared with room temperature, whereas temperate lineage adults demonstrated a 66% reduction in preference for dogs and a slight increase in preference for humans. Fewer nymphs chose either host at 38°C than at room temperature in both lineages. These results demonstrate that risk of disease transmission to humans may be increased during periods of hot weather, where either lineage is present, and that hot weather events associated with climatic change may result in more frequent rickettsial disease outbreaks.

Human babesiosis is a life-threatening infectious disease that causes societal and economic impact worldwide. Several species of Babesia cause babesiosis in terrestrial vertebrates, including humans. A one-day clinic was held in Ontario, Canada, to see if a red blood cell parasite, which is present in blacklegged ticks, Ixodes scapularis, is present in humans. Based on PCR testing and DNA sequencing of the 18S rRNA gene, we unveiled B. odocoilei in two of 19 participants. DNA amplicons from these two patients are almost identical matches with the type strains of B. odocoilei in GenBank. In addition, the same two human subjects had the hallmark symptoms of human babesiosis, including night sweats, chills, fevers, and profound fatigue. Based on symptoms and molecular identification, we provide substantive evidence that B. odocoilei is pathogenic to humans. Dataset reveals that B. odocoilei serologically cross-reacts with Babesia duncani. Clinicians must realize that there are more than two Babesia spp. in North America that cause human babesiosis. This discovery signifies the first report of B. odocoilei causing human babesiosis.

The composition of tick microbiomes varies both within and among tick species. Whether this variation is intrinsic (related to tick characteristics) or extrinsic (related to vertebrate host and habitat) is poorly understood but important, as microbiota can influence the reproductive success and vector competence of ticks. We aimed to uncover what intrinsic and extrinsic factors best explain the microbial composition and taxon richness of 11 species of neotropical ticks collected from eight species of small mammals in 18 forest fragments across central Panama. Microbial richness varied among tick species, life stages, and collection sites but was not related to host blood source. Microbiome composition was best explained by tick life stage, with bacterial assemblages of larvae being a subset of those of nymphs. Collection site explained most of the bacterial taxa with differential abundance across intrinsic and extrinsic factors. Francisella and Rickettsia were highly prevalent, but their proportional abundance differed greatly among tick species, and we found both positive and negative cooccurrence between members of these two genera. Other tick endosymbionts (e.g., Coxiella and Rickettsiella) were associated with specific tick species. In addition, we detected Anaplasma and Bartonella in several tick species. Our results indicate that the microbial composition and richness of neotropical ticks are principally related to intrinsic factors (tick species and life stage) and collection site. Taken together, our analysis informs how tick microbiomes are structured and can help anchor our understanding of tick microbiomes from tropical environments more broadly. IMPORTANCE Blood-feeding arthropod microbiomes often play important roles in disease transmission, yet the factors that structure tick microbial communities in the Neotropics are unknown. Utilizing ticks collected from live animals in neotropical forest fragments, this study teases apart the contributions of intrinsic and extrinsic tick-associated factors on tick microbial composition as well as which specific microbes contribute to differences across tick species, tick life stages, the mammals they fed on, and the locations from where they were sampled. Furthermore, this study provides revelations of how notable tick-associated bacterial genera are interacting with other tick-associated microbes as well as the forest animals they encounter.

Sarcoptic mange epidemics can have long-lasting impacts on susceptible wildlife populations, potentially contributing to local population declines and extirpation. Since 2013, there have been 460 reported cases of sarcoptic mange in an urban population of endangered San Joaquin kit foxes (Vulpes macrotis mutica) in Bakersfield, CA, with many of them resulting in fatality. As part of a multifaceted response to mitigate mange-caused mortalities and reduce this conservation threat, a 2-yr randomized field trial was conducted to assess the efficacy of long-acting flumethrin collars against sarcoptic mange in kit foxes. Thirty-five kit foxes living in a high-density population on a college campus were captured, examined, administered selamectin, and each fox randomly assigned to either receive a flumethrin collar placed within a VHF radio collar or a VHF radio collar without flumethrin. The survival and mange-infestation status of study animals was monitored via radio telemetry, remote cameras, and periodic recapture examinations and compared among treated and control kit foxes using a Cox proportional hazards model. The average time to onset of mange for treated kit foxes (176 days) was similar to controls (171 days) and treatment with flumethrin did not significantly reduce mange risk for all kit foxes. Kit foxes that had a mild mange infestation at the beginning of the study were four times more likely to develop mange again, regardless of flumethrin treatment, compared with kit foxes that had no signs at initial recruitment. This study demonstrates an approach to evaluating population-level protection and contributes to the limited literature on efficacy, safety, and practicality of acaricides in free-ranging wildlife.

Southern sea otters (Enhydra lutris nereis) rely on intact pelage for thermoregulation, and thus clinically significant demodicosis and associated alopecia can cause morbidity and death.This study aimed to describe lesions associated with follicular Demodex sp. infestation, estimate the prevalence and intensity of infestation, describe mite distribution across key anatomical regions, and assess mite presence or absence in relation to lesions and host risk factors.Twenty necropsied, wild southern sea otters that stranded along the central California coast from 2005 to 2018.Grossly normal and abnormal integument from the head, perineum, genitals, mamillary papillae and limbs was assessed microscopically for mites and mite-associated pathological findings.Intrafollicular mites were observed in the integument of 55% of otters and 20% had clinical demodicosis. Demodicosis was considered to be contributory to death or euthanasia in two cases. Although Demodex sp. mites often were observed microscopically in grossly normal skin, the presence of multiple densely-packed intrafollicular mites generally was associated with pigmentary incontinence, ectatic follicles, lymphoplasmacytic perifolliculitis, and neutrophilic and lymphoplasmacytic, dermal inflammation. Other findings included epidermal hyperplasia, orthokeratotic hyperkeratosis of epidermis and follicular epithelium, concurrent pyoderma and cell necrosis. Perioral integument, especially of the chin, had the highest prevalence of mites and the highest mite density, suggesting facial contact as a means of mite transmission.Our research confirmed demodectic mange as a contributor to morbidity and mortality in sea otters, with important implications for clinical care, rehabilitation and conservation.La loutre de mer de Californie (Enhydra lutris nereis) utilise son pelage intact pour sa thermorégulation et ainsi, une démodécie cliniquement significative et l’alopécie associée peuvent causer une morbidité et la mort. HYPOTHÈSES/OBJECTIFS: Cette étude a pour but de décrire les lésions associées à une infestation folliculaire de Demodex sp., estimer la prévalence et l’intensité de l’infestation, décrire la distribution des acariens à l’aide de régions anatomiques clés et déterminer la présence ou l’absence d’acariens et les facteurs de risque des hôtes.Vingt loutres de mer de Californie sauvages ont été autopsiées après s’être échouées le long de la côte californienne de 2005 à 2018. MATÉRIELS ET MÉTHODES: La peau macroscopiquement normale et anomale de la tête, du périnée, des zones génitales, des papilles mammaires et des membres a été évaluée microscopiquement pour les acariens et les lésions pathologiques liées aux acariens. RÉSULTATS: Les acariens intrafolliculaires ont été observés dans la peau de 55% des loutres et 20% avaient une démodécie clinique. La démodécie a été considérée comme contribuant à la mort ou à l’euthanasie dans deux cas. Bien que les acariens Demodex sp. soient souvent observées dans la peau macroscopiquement normale, la présence multiple d’acariens intrafolliculaires regroupés en amas denses était généralement associée avec de l’incontinence pigmentaire, des follicules ectatiques, une périfolliculite lymphoplasmocytaire et une inflammation dermique neutrophilique et lymphoplasmocytaire. Les autres données regroupent une hyperplasie épidermique, une hyperkératose orthokératosique de l’épiderme et de l’épithélium folliculaire, une pyodermite concomitante et une nécrose cellulaire. La peau péri-orale, en particulier le menton, avait la prévalence la plus élevée d’acariens et la densité en acarien la plus élevée suggérant un contact facial comme mode de transmission.Nos recherches confirment que la démodécie participe à la morbidité et à la mortalité des loutres de mer avec implications importantes pour les soins de cliniques, de réhabilitation et de conservation.INTRODUCCIÓN: las nutrias marinas del sur (Enhydra lutris nereis) dependen de un pelaje en buenas condiciones para la termorregulación y, por lo tanto, la demodicosis clínicamente significativa y la alopecia asociada pueden causar morbilidad y muerte. HIPÓTESIS/OBJETIVOS: Este estudio tuvo como objetivo describir las lesiones asociadas con la infestación folicular por Demodex sp., estimar la prevalencia e intensidad de la infestación, describir la distribución de ácaros en regiones anatómicas clave y evaluar la presencia o ausencia de ácaros en relación con las lesiones y los factores de riesgo del huésped. ANIMALES: Veinte nutrias marinas salvajes del sur necropsiadas que quedaron varadas a lo largo de la costa central de California entre 2005 y 2018. MÉTODOS Y MATERIALES: Se evaluó microscópicamente el tegumento macroscópicamente normal y anormal de la cabeza, el perineo, los genitales, las papilas mamilares y las extremidades para detectar ácaros y hallazgos patológicos asociados a los ácaros. RESULTADOS: Se observaron ácaros intrafoliculares en el tegumento del 55% de las nutrias y el 20% presentó demodicosis clínica. Se consideró que la demodicosis contribuyó a la muerte o la eutanasia en dos casos. Aunque ácaros de Demodex sp. a menudo se observaron microscópicamente en piel macroscópica normal, la presencia de múltiples ácaros intrafoliculares densamente empaquetados generalmente se asoció con incontinencia pigmentaria, folículos ectásicos, perifoliculitis linfoplasmocítica e inflamación dérmica neutrofílica y linfoplasmacítica. Otros hallazgos incluyeron hiperplasia epidérmica, hiperqueratosis ortoqueratósica de epidermis y epitelio folicular, pioderma concurrente y necrosis celular. El tegumento perioral, especialmente del mentón, tuvo la mayor prevalencia de ácaros y la mayor densidad de ácaros, lo que sugiere el contacto facial como medio de transmisión de ácaros. CONCLUSIONES E IMPORTANCIA CLÍNICA: Nuestra investigación confirmó que la sarna demodécica contribuye a la morbilidad y mortalidad en las nutrias marinas, con importantes implicaciones para la atención clínica, la rehabilitación y la conservación.Der Seeotter des Südpazifiks (Enhydra lutris nereis) benötigt zur Thermoregulierung zwingend ein intaktes Haarkleid und daher kann eine klinisch signifikante Demodikose und eine damit einhergehende Alopezie Erkrankung und Tod verursachen.Diese Studie zielte darauf ab, Veränderungen, die mit einer follikulären Demodex sp. Infektion einhergehen, zu beschreiben, die Prävalenz und die Intensität des Befalls abzuschätzen, die Milbenverteilung an den anatomischen Schlüsselregionen zu beschreiben, und die Milbenpräsenz oder deren Fehlen in Relation zu den Veränderungen und den Risikofaktoren des Wirtes zu beurteilen.Es wurden zwanzig wilde südliche Seeotter, die entlang der Küste Zentralkaliforniens zwischen 2005 und 2018 gestrandet waren, autopsiert.Makroskopisch normale und abnormale Haut von Kopf, Perineum, den Genitalien, der Brustwarzen und der Extremitäten wurden mikroskopisch auf Milben und auf pathologische Befunde im Zusammenhang mit Milben untersucht.Es wurden intrafollikuläre Milben in der Haut von 55% der Otter gefunden, wobei 20% von ihnen eine klinische Demodikose aufwiesen. Die Demodikose wurde als ursächlich für den Tod und die Euthanasie in zwei Fällen angesehen. Obwohl Demodex sp. Milben oft mikroskopisch in mit freiem Auge normaler Haut gefunden wurden, wurde das Vorkommen von multiplen dicht gepackten intrafollikulären Milben generell mit Pigmentinkontinenz, ektatischen Follikeln, lymphoplasmazytischer Perifollikulitis, und neutrophiler und lymphoplasmazytischer, dermaler Entzündung gesehen. Die Haut rundum den Mund, vor allem am Kinn, zeigte die höchste Prävalenz von Milben und die höchste Milbendichte, was auf einen Gesichtskontakt als Übertragungsweg für die Milben hinweist.Unsere Forschung bestätigte die Demodexmilbe als Beitragende zur Morbidität und Mortalität der Seeotter, was wichtige Implikationen für ihre klinische Versorgung, Rehabilitation und Erhaltung darstellt.背景: 南方ラッコ (Enhydra lutris nereis)の体温調節は無傷の毛に依存するため、臨床的に著しいニキビダニ症およびそれに伴う脱毛症は、病的疾患や死亡の原因となることがある。 仮説/目的: 本研究の目的は、毛包寄生性ニキビダニ属に関連する病変の記述、寄生の有病率および強度の推定、主要な解剖学的領域におけるダニの分布の記述、病変および宿主の危険因子との関連におけるダニの有無を評価することであった。 被験動物: 2005年から2018年までカリフォルニア中央海岸で座礁した野生の南方ラッコ20頭を剖検した。 材料と方法: 頭部、会陰部、生殖器、乳頭および四肢の総じて正常または異常な皮膚を顕微鏡的に評価し、ダニおよびダニに関連した病理学的所見を調査した。 結果: ラッコの55%の皮膚には毛包内にダニが観察され、20%には臨床的にニキビダニ症が認められた。そのうち2例は死亡または安楽死の原因と考えられた。正常な皮膚においてしばしばニキビダニが顕微鏡下で観察されたが、毛包内に密に詰まった複数のダニの存在は、一般的に色素脱、拡張性毛包、リンパ球形質細胞性毛包周囲炎、好中球性およびリンパ球形質細胞性の真皮の炎症と関連していた。その他の所見としては、表皮過形成、表皮および毛包漏斗部の正角化性角化亢進、膿皮症および細胞壊死を併発していた。口周囲の皮膚、特に顎部でダニの有病率が最も高く、ダニ密度も最も高かったことから、顔面接触がダニの感染手段であることが示唆された。 結論と臨床上の重要性: 本研究は、ラッコの罹患率および死亡率の一因であるニキビダニを確認し、臨床ケア、リハビリテーション、管理に重要な意味を持つことを示した。.背景: 方海獭依赖于被毛完整来进行体温调节, 因此具有临床意义的蠕形螨病和造成的脱毛可导致其发病和死亡。 假设/目的: 本研究旨在描述毛囊蠕形螨侵染造成的病变, 评估侵染的流行率和严重程度, 描述关键解剖区域的螨虫分布, 并评估是否存在造成病变的螨虫, 以及宿主风险因素。 动物: 2005年至2018年, 在加利福尼亚中部海岸搁浅并进行尸检的20只野生南方海獭。 方法和材料: 采自外观正常和异常的头部、会阴、生殖器、乳头和四肢皮肤, 评估显微镜下螨虫及螨虫相关的病理学结果。 结果: 在55%的水獭皮肤中观察到毛囊内螨虫, 20%患有临床蠕形螨病。在2个病例中, 蠕形螨病导致了死亡或因此而人道处死。尽管在外观正常的皮肤中, 通过显微镜经常能观察到蠕形螨虫体, 多处毛囊内出现的密集螨虫, 通常造成色素失禁、毛囊扩张、淋巴浆细胞性毛囊周炎以及中性粒细胞和淋巴浆细胞性真皮炎症。其他结果包括表皮增生、表皮和毛囊上皮的正角化性过度角化、并发脓皮病和细胞坏死。口周皮肤, 尤其是颏部, 螨虫侵染率最高, 螨虫密度最高, 这提示面部接触是螨虫传播的一种途径。 结论和临床重要性: 我们的研究证实蠕形螨是海獭发病和死亡的因素, 临床护理、康复和保护具有重要意义。.As lontras do mar do Sul (Enhydra lutris nereis) dependem da pelagem intacta para termorregulação e, portanto, demodiciose clinicamente significativa e alopecia associada podem causar morbidade e morte. HIPÓTESE/OBJETIVOS: Este estudo teve como objetivo descrever lesões associadas à infestação folicular por Demodex sp., estimar a prevalência e intensidade da infestação, descrever a distribuição de ácaros nas principais regiões anatômicas e avaliar a presença ou ausência de ácaros em relação a lesões e fatores de risco do hospedeiro.Vinte lontras do mar do Sul selvangens necropsiadas que ficaram presas ao longo da costa central da Califórnia de 2005 a 2018. MÉTODOS E MATERIAIS: Tegumento grosseiramente normal e anormal da cabeça, períneo, genitais, papilas mamilares e membros foram avaliados microscopicamente para pesquisa de ácaros ácaros e achados patológicos associados aos ácaros.Observou-se ácaros intrafoliculares no tegumento de 55% das lontras e 20% apresentaram demodiciose clínica. A demodiciose foi considerada como contribuinte para a morte ou eutanásia em dois casos. Embora os ácaros Demodex sp. tenham sido frequentemente observados microscopicamente na pele grosseiramente normal, a presença de múltiplos ácaros intrafoliculares densamente compactados geralmente estava associada a incontinência pigmentar, folículos ectáticos, perifoliculite linfoplasmocitária e inflamação dérmica neutrofílica e linfoplasmocitária. Outros achados incluíram hiperplasia epidérmica, hiperceratose ortoqueratótica da epiderme e epitélio folicular, pioderma concomitante e necrose celular. O tegumento perioral, principalmente do mento, apresentou a maior prevalência de ácaros e a maior densidade de ácaros, sugerindo o contato facial como meio de transmissão dos ácaros. CONCLUSÕES E IMPORTÂNCIA CLÍNICA: Nossa pesquisa confirmou a sarna demodécica como contribuinte para a morbidade e mortalidade em lontras marinhas, com implicações importantes para o atendimento clínico, reabilitação e conservação.

Songbirds widely disperse ticks that carry a diversity of pathogens, some of which are pathogenic to humans. Among ticks commonly removed from songbirds, the blacklegged tick, Ixodes scapularis, can harbor any combination of nine zoonotic pathogens, including Babesia species. From May through September 2019, a total 157 ticks were collected from 93 songbirds of 29 species in the Canadian provinces of Ontario and Qu&eacute, bec. PCR testing for the 18S gene of Babesia species detected Babesia odocoilei in 12.63% of I. scapularis nymphs parasitizing songbirds in Ontario and Qu&eacute, bec, none of the relatively small numbers of Ixodes muris, Ixodes brunneus, or Haemaphysalis leporispalustris were PCR-positive. For ticks at each site, the prevalence of B. odocoilei was 16.67% in Ontario and 8.89% and 5.26% in Qu&eacute, bec. Of 31 live, engorged I. scapularis larvae and nymphs held to molt, 25 ticks completed the molt, five of these molted ticks were positive for B. odocoilei. PCR-positive ticks were collected from six bird species&mdash, namely, Common Yellowthroat, Swainson&rsquo, s Thrush, Veery, House Wren, Baltimore Oriole, and American Robin. Phylogenetic analysis documented the close relationship of B. odocoilei to Babesia canis canis and Babesia divergens, the latter a known pathogen to humans. For the first time in Canada, we confirm the transstadial passage of B. odocoilei in I. scapularis molting from larvae to nymphs. A novel host record reveals I. scapularis on a Palm Warbler. Our findings show that B. odocoilei is present in all mobile life stages of I. scapularis, and it is widely dispersed by songbirds in Ontario and Qu&eacute, bec.

Background In 2013, sarcoptic mange, caused by Sarcoptes scabiei mites, precipitated a catastrophic decline of the formerly stable urban population of endangered San Joaquin kit foxes (Vulpes macrotis mutica) in Bakersfield, California, USA. In 2019, a smaller sarcoptic mange outbreak affected kit foxes 58 km southwest of Bakersfield in the town of Taft, California. To determine whether the Taft outbreak could have occurred as spillover from the Bakersfield outbreak and whether epidemic control efforts must involve not only kit foxes but also sympatric dogs (Canis lupus familiaris), coyotes (Canis latrans), and red foxes (Vulpes vulpes), we evaluated genotypes and gene flow among mites collected from each host species. Methods We used 10 Sarcoptes microsatellite markers (SARM) to perform molecular typing of 445 S. scabiei mites collected from skin scrapings from twenty-two infested kit foxes, two dogs, five coyotes, and five red foxes from Bakersfield, Taft, and other nearby cities. Results We identified 60 alleles across all SARM loci; kit fox- and red fox-derived mites were relatively monomorphic, while genetic variability was greatest in Bakersfield coyote- and dog-derived mites. AMOVA analysis documented distinct mite populations unique to hosts, with an overall FST of 0.467. The lowest FST (i.e. closest genetic relationship, FST = 0.038) was between Bakersfield and Taft kit fox-derived mites while the largest genetic difference was between Ventura coyote- and Taft kit fox-derived mites (FST = 0.843). Conclusions These results confirm the close relationship between the Taft and Bakersfield outbreaks. Although a spillover event likely initiated the kit fox mange outbreak, mite transmission is now primarily kit fox-to-kit fox. Therefore, any large-scale population level intervention should focus on treating kit foxes within the city.

The apicomplexan parasite Toxoplasma gondii has been found in more than 350 species of homoeothermic vertebrates in diverse climates and geographic areas. In most animals, T. gondii produces mild or asymptomatic infection. However, acute and hyperacute toxoplasmosis is associated with high mortality rates observed in Neotropical primates (NP) in captivity. NP are distributed in 20 countries across the Americas, and although infection has been reported in certain countries and species, toxoplasmosis in the wild and its impact on NP population survival is unknown. Differences among species in exposure rates and disease susceptibility may be due in part to differences in host behavior and ecology. Costa Rica has four species of NP, howler (Alouatta palliata), spider (Ateles geoffroyi), capuchin (Cebus imitator), and squirrel monkeys (Saimiri oerstedii). Here we report for the first time NP exposure to T. gondii using a modified agglutination test (MAT) in 245 serum samples of NP (198 wild and 47 from captivity) from Costa Rica. Associations of serostatus with environmental (forest cover, annual mean temperature), anthropogenic (human population density), and biological (sex) variables in howler and capuchin monkeys were evaluated. The seroprevalence among wild NP was 11.6% (23/198), compared with 60% (28/47) in captive monkeys, with significant differences between species (P 8192), suggesting higher exposure due to management factors and increased life span in captivity. Seropositivity in howler monkeys was positively related to forest cover and inversely related to annual rainfall. For capuchins, annual rainfall was inversely related to seropositivity. Surveillance of T. gondii in NP in captivity and in the wild is required to understand drivers of the infection and develop novel strategies to protect them.

The critically endangered Amargosa vole (Microtus californicus scirpensis) is found only in rare marsh habitat near Tecopa, California in a plant community dominated by three-square bulrush (Schoenoplectus americanus). Since the earliest research on the Amargosa vole, the existing paradigm has been that these voles are obligatorily dependent on bulrush as their only food source and for the three-dimensional canopy and litter structure it provides for predator avoidance. However, no prior research has confirmed the diet of the Amargosa vole. In this study we characterized the Amargosa vole' nutritional needs, analyzed the quality of bulrush by forage analysis, and performed microhistological and metabarcoding analyses of vole feces to determine what foods were consumed in the wild. All bulrush plant tissues analyzed were low in fat (from 0.9% of dry matter in roots to 3.6% in seeds), high in neutral detergent fiber (from 5.9% in rhizomes to 33.6% in seeds), and low in protein (7.3-8.4%). These findings support the conclusion that bulrush alone is unlikely to support vole survival and reproduction. Fecal microhistology and DNA metabarcoding revealed relatively diverse diets including plants in 14 families, with rushes (Juncaceae), bulrushes (Cyperaceae), and grasses (Poaceae) being the most common diet items. On microhistology, all analyzed samples contained bulrush, sedges (Carex sp.), rushes (Juncus sp.), and beaked spikerush (Eleocharis rostrellata) even from marshes where non-bulrush plants were uncommon. There was evidence of insects at

Sarcoptic mange epidemics can have long-lasting impacts on susceptible wildlife populations, potentially contributing to local population declines and extirpation. Since 2013, there have been 460 reported cases of sarcoptic mange in an urban population of endangered San Joaquin kit foxes (

Leptospirosis is reported infrequently in wild and domestic felids. We estimated the prevalence of Leptospira spp. infection and exposure using real-time PCR and serology, respectively, in 136 mountain lions (Puma concolor) and 39 bobcats (Lynx rufus) that died or were euthanized between 2009 and 2017 from several regions of California, US. Felids were classified as Leptospira-positive if they were test-positive using real-time PCR targeting the LipL32 gene of pathogenic Leptospira spp. or microscopic agglutination test for six serovars of Leptospira spp. The overall Leptospira spp. prevalence was 46% (63/136) for mountain lions and 28% (11/39) for bobcats. The most common serovar detected in both felid species was Leptospira interrogans serovar Pomona. Age class and geographic location were significantly associated with Leptospira spp. in mountain lions, but not in bobcats. Interstitial nephritis, predominately lymphocytic, was diagnosed in 39% (41/106) of mountain lions and 16% (4/25) of bobcats evaluated histologically and was significantly associated with being Leptospira spp.-positive in both species. Our findings suggest that Leptospira spp. infection is common and widespread in California's wild felids and may have clinical impacts on renal and overall health of individuals. Key words: Bobcat, Leptospira spp., leptospirosis, Lynx rufus, mountain lion, nephritis, pathology, Puma concolor.

Staff at a university laboratory responsible for management of a captive insurance colony of endangered Amargosa voles ( Microtus californicus scirpensis) discovered an outbreak of tropical rat mites ( Ornithonyssus bacoti) infesting 106 voles. This bloodsucking mesostigmatid mite typically occurs in laboratory settings and can cause weight loss, wounds, or other negative impacts on health. The source of the infestation was likely feral rodents, and the route was suspected to be straw bedding. Twenty-nine of the 106 (27.4%) infested voles developed ulcerated dorsal skin lesions that resolved when treated with topical selamectin. A triad approach was implemented to eradicate the mites, consisting of environmental management, individual animal treatment, and training. Voles were moved individually into a clean room containing only autoclaved materials (including straw), cages were treated with permethrin-impregnated cotton, treatment order was instituted to avoid transferring mites, and voles coming from outside were quarantined. All animals in an infested room were treated with topical selamectin, and personnel were trained on risks and new procedures. No adverse effects from the use of selamectin were identified, and this efficient protocol does not require the long-term use of acaricides. This report documents infestation of an endangered rodent with an exotic parasite, safe use of permethrin and selamectin in this species, and comprehensive management to manage a large infestation.

Increasing rates of Rocky Mountain spotted fever (RMSF) in the southwestern United States and northern Mexico underscore the importance of studying the ecology of the brown dog tick, Rhipicephalus sanguineus, the vector in that region. This species is reported to comprise distinct tropical and temperate lineages that may differ in vectorial capacity for RMSF and are hypothesized to be limited in their geographical range by climatic conditions. In this study, lineage was determined for ticks from 9 locations in California, Arizona, and Mexico by DNA sequencing of 12S, 16S, and D-loop ribosomal RNA. As expected, sites in northern California and eastern Arizona had temperate-lineage ticks, and phylogenetic analysis revealed considerable genetic variability among these temperate-lineage ticks. However, tropical-lineage ticks extended north from Oaxaca, Mexico were well established along the entire border from San Diego, California to western Arizona, and were found as far north as Lytle Creek near Los Angeles, California (a site where both lineages were detected). Far less genetic variability in the tropical lineage despite the large geographical distances is supportive of a hypothesis of rapid northward expansion. Discovery of the tropical lineage north of the identified climatic limitations suggests that more work is needed to characterize this tick's ecology, vectorial capacity, expansion, possible evolution, and response to climate change.