Improving rapid detection methods for pathogens is important for research as we collectively aim to improve the health of ecosystems globally. In the northern hemisphere, the success of salmon (Oncorhynchus spp.) populations is vitally important to the larger marine, aquatic, and terrestrial ecosystems they inhabit. This has led to managers cultivating salmon in hatcheries and aquaculture to bolster their populations, but young salmon face many challenges, including diseases such as bacterial kidney disease (BKD). Early detection of the BKD causative agent, Renibacterium salmoninarum, is useful for managers to avoid outbreaks in hatcheries and aquaculture stocks to enable rapid treatment with targeted antibiotics. Isothermal amplification and CRIPSR-Cas12a systems may enable sensitive, relatively rapid, detection of target DNA molecules from environmental samples compared to quantitative PCR (qPCR) and culture methods. We used these technologies to develop a sensitive and specific rapid assay to detect R. salmoninarum from water samples using isothermal recombinase polymerase amplification (RPA) and an AsCas12a RNA-guided nuclease detection. The assay was specific to R. salmoninarum (0/10 co-occurring or closely related bacteria detected) and sensitive to 0.0128 pg/µL of DNA (approximately 20–40 copies/µL) within 10 min of Cas activity. This assay successfully detected R. salmoninarum environmental DNA in 14/20 water samples from hatcheries with known quantification for the pathogen via previous qPCR (70% of qPCR-positive samples). The RPA-CRISPR/AsCas12a assay had a limit of detection (LOD) of >10 copies/µL in the hatchery water samples and stochastic detection below 10 copies/µL, similar to but slightly higher than the qPCR assay. This LOD enables 37 C isothermal detection, potentially in the field, of biologically relevant levels of R. salmoninarum in water. Further research is needed to develop easy-to-use, cost-effective, sensitive RPA/CRISPR-AsCas12a assays for rapidly detecting low concentrations of wildlife pathogens in environmental samples.

Introduced fungal pathogens have caused declines and extinctions of naïve wildlife populations across vertebrate classes. Consequences of introduced pathogens to hosts with small ranges might be especially severe because of limited redundancy to rescue populations and lower abundance that may limit the resilience of populations to perturbations like disease introduction. As a complement to biosecurity measures to prevent the spread of pathogens, surveillance programs may enable early detection of pathogens, when management actions to limit the effects of pathogens on naïve hosts might be most beneficial. We analyzed surveillance data for the endangered and narrowly endemic Dixie Valley toad (Anaxyrus [= Bufo] williamsi) from two time periods (2011–2014 and 2019–2021) to estimate the minimum detectable prevalence of the amphibian fungal pathogen Batrachochytrium dendrobatidis (Bd). We assessed if detection efficiency could be improved by using samples from both Dixie Valley toads and co-occurring introduced American bullfrogs (Lithobates catesbeianus) and literature-derived surveillance weights. We further evaluated a weighted surveillance design to increase the efficiency of surveillance efforts for Bd within the toad's small (<6 km²) range. We found that monitoring adult and larval American bullfrogs would probably detect Bd more efficiently than monitoring Dixie Valley toads alone. Given that no Bd was detected, minimum detectable prevalence of Bd was <3% in 2011–2014, and <5% (Dixie Valley toads only) and <10% (American bullfrogs only) in 2019–2021. Optimal management for Bd depends on the mechanisms underlying its apparent absence from the range of Dixie Valley toads, but a balanced surveillance scheme that includes sampling American bullfrogs to increase the likelihood of detecting Bd, and adult Dixie Valley toads to ensure broad spatial coverage where American bullfrogs do not occur, would probably result in efficient surveillance, which might permit timely management of Bd if it is detected.

Exposure of a dam to pathogens may potentially affect her fawns positively or negatively. Mammalian females transfer immunologic protection to their offspring via colostrum obtained while nursing. Conversely, chronic diseases in dams may potentially result in small and weak neonates, reduced milk production or quality, or infection. Little is known about how pathogen exposure in adult female white-tailed deer (Odocoileus virginianus) affects offspring survival. Our objective was to assess pathogen exposure for female white-tailed deer and subsequent survival rates of fawns in Dunn and Grant counties, North Dakota, and Perkins County, South Dakota, USA. We collected blood serum from 150 adult female deer during 2014. We compared survival of 49 fawns to maternal exposure to 10 pathogens from 37 of 150 adult females. There was no difference in fawn mass between dams based on antibody status and no difference in fawn survival for nine pathogens. The 12-wk survival for fawns born to mothers with antibodies against bovine herpesvirus 1 (BoHV-1, causing infectious bovine rhinotracheitis) was lower than for fawns born from mothers without antibodies against BoHV-1; however, the indirect or direct impacts of BoHV-1 exposure in mothers on fawn survival are unclear. Although our findings suggest that the cost of exposure to previous diseases may have minimal impact on short-term fawn survival for most pathogens, additional research with increased sample sizes is needed to confirm our findings.

The small Indian mongoose (Urva auropuncata) is a rabies reservoir in Puerto Rico and accounts for over 70% of reported animal rabies cases annually. The presence of rabies virus–neutralizing antibodies (RVNA) is often used as a tool to measure exposure to rabies virus in wildlife populations. We conducted a serosurvey of mongooses at 11 sites representing six habitat types across Puerto Rico. We collected a serum sample from 464 individual mongooses during 2014–21. Overall, 80/464 (17.0%; 95% confidence interval, 14.1–20.9%; 55 male, 23 female, and two sexes not recorded) of individual mongooses sampled across all habitats were RVNA positive. The geometric mean (SD) RVNA titer for 80 unique seropositive animals was 0.58 (2.92) IU/mL. Our models indicated that the probability of mongooses being RVNA seropositive mostly varied by habitat, with some influence of sex in the individual-level analyses. Population-level RVNA seroprevalence is dynamic in mongoose populations, but these data may shed light on rabies virus transmission across regions to help inform rabies management activities in Puerto Rico.

A Eurasian lineage highly pathogenic avian influenza virus (HPAIV) of the clade 2.3.4.4b (Goose/Guangdong lineage) was detected in migratory bird populations in North America in December 2021, and it, along with its reassortants, have since caused wild and domestic bird outbreaks across the continent. Relative to previous outbreaks, HPAIV cases among wild birds in 2022 exhibited wider geographic extent within North America and higher levels of mortality, suggesting the potential for population-level impacts. Given the possible conservation implications of HPAIV in wild birds, natural resource managers have sought guidance on actions that may mitigate negative effects of disease among North American bird populations, including modification of existing management practices. Banding of waterfowl is a critical tool for population management for several harvested species in North America, but some banding techniques, such as bait trapping, can lead to increased congregation of waterfowl, potentially altering HPAIV transmission. We used an expert opinion exercise to assess how bait trapping of dabbling ducks in Canada may influence HPAIV transmission and wild bird health. The expert group found that it is moderately likely that bait trapping of dabbling ducks in wetlands will significantly increase the transmission of HPAIV among individual ducks, but there is a low probability that this will result in significant population-level effects on North American dabbling ducks. Considering the lack of empirical work studying how capture and handling methods may change transmission of HPAIV among waterfowl, as well as the importance of bait trapping for waterfowl management in North America, future work should focus on filling knowledge gaps pertaining to the influence of baiting on HPAIV occurrence to better inform banding procedures and management decision making.

The aim of this study was to compare the effects of two anesthetic induction protocols for long procedures carried out in the field in Tapiridae. Sixteen tapirs were divided into two groups (n=8) receiving either detomidine (DET) or dexmedetomidine (DEX) for anesthetic induction. All animals were anesthetized by intramuscular administration of a combination of ketamine (1.5 mg/kg), midazolam (0.2 mg/kg), plus either DET (0.04 mg/kg) or DEX (0.007 mg/kg). Anesthetic maintenance was by continuous infusion of ketamine, midazolam, and glyceryl guaiacol ether at 2 mg/kg per hour, 0.1 mg/kg per hour, and 100 mg/kg per hour, respectively). The animals were kept anesthetized for a total of 50 min to allow physical examination and collection of biological material as part of a research program, and physiological variables (heart rate [HR], respiratory rate, oxyhemoglobin saturation [SpO₂], rectal temperature [RT], mean arterial pressure [MAP], blood glucose [GLI], and cortisol) and electrocardiogram were recorded during anesthesia. Anesthetic recovery was monitored by two researchers who were not informed of the induction protocol group. The recorded results were statistically evaluated. In both groups there was an initial increase in MAP, which subsequently decreased; RT gradually decreased during anesthesia; HR and GLI increased throughout the procedure; SpO₂ was below normal throughout the procedure. Cortisol levels were significantly higher in the DEX group than in the DET group. Also, the animals in the DEX group had a longer recovery time than those in the DET group. On the basis of the results, we conclude that the combination of alpha-2 agonists and midazolam, ketamine, and glyceryl guaicol ether is an appropriate protocol for the anesthesia of tapirs in the field. However, in moderately extended procedures oxygen supplementation is recommended. Additionally, DEX resulted in fewer cardiovascular effects and longer-lasting sedation than DET.

We evaluated a combination of nalbuphine HCl (40 mg/mL), azaperone tartrate (10 mg/mL), and medetomidine HCl (10 mg/mL), a combination known as NAM or NalMed-A, in 23 ringtails (Bassariscus astutus) during 29 handling events for a radio-collaring study in southern Oregon, US, from August 2020 to March 2022. The combination was delivered to ringtails by hand injection at 0.075 mL NAM per estimated 1 kg body mass. The mean (± standard deviation, SD) dosage calculated post hoc was 3.366 (±0.724) mg/kg nalbuphine, 0.841 (±0.181) mg/kg medetomidine, and 0.841 (±0.181) mg/kg azaperone. All captured ringtails were effectively immobilized with a mean (SD) induction time of 13.24 (±3.57) min. The medetomidine and nalbuphine components were antagonized with a combination of atipamezole and naltrexone HCl with a mean (SD) recovery time of 2.48 (±1.94) min. This combination appeared to be safe and effective for immobilizing ringtails with a low volume dose, smooth antagonism, and rapid recovery. In addition, NAM does not contain any drugs that are US Drug Enforcement scheduled, which makes it useful for immobilization procedures by wildlife professionals in the US.

Mortality patterns in cetaceans are critical to understanding population health. Common bottlenose dolphins (Tursiops truncatus truncatus) inhabiting the Indian River Lagoon (IRL), Florida have been subjected to four unusual mortality events (UMEs), highlighting the need to evaluate morbidity and mortality patterns. Complete gross examinations were conducted on 392 stranded dolphins and histopathological analyses were conducted for 178 animals (2002–2020). The probable causes of mortality were grouped by etiologic category: degenerative, metabolic, nutritional, inflammatory (infectious and noninfectious disease), and trauma. Probable cause of mortality was determined in 57% (223/392) of cases. Inflammatory disease (infectious/noninfectious) and trauma were the most common. Inflammatory disease accounted for 41% of cases (91/223), with the lungs (pneumonia) most commonly affected. Trauma accounted for 36% of strandings (80/223). The majority of trauma cases were due to anthropogenic activities (entanglement, fishing gear or other debris ingestion, and propeller strikes), accounting for 58% of trauma cases (46/80). Natural trauma (prey-associated esophageal obstruction or asphyxiation, shark bites, and stingray interactions) accounted for 12% of all cases (26/223), and trauma of undetermined origin was identified in 4% of cases (8/223). Starvation or inanition (nutritional) were the probable cause of mortality in 17% of cases and peaked during the 2013 UME (61% of cases). Degenerative and metabolic etiologies accounted for 5% of cases. This study represents the most comprehensive evaluation of morbidity and mortality patterns in IRL dolphins. Because IRL dolphins are routinely exposed to anthropogenic threats and have endured multiple UMEs, these baseline data are critical to the conservation and management of this population.

A retrospective study was conducted to categorize and describe the causes of mortality in harbor seals (Phoca vitulina) along the British Columbia coast that presented to the Vancouver Aquarium Marine Mammal Rescue Centre (MMR) for rehabilitation from 2012 to 2020. Medical records for 1,279 predominantly perinatal live-stranded harbor seals recovered in this region were reviewed. Approximately 20.0% (256 individuals; 137 males, 118 females, 1 unknown) of these animals died while at MMR. Infectious disease was the most common cause of death, accounting for 60.5% of mortality across all age classes. This was followed by nonanthropogenic trauma (7.1%), metabolic illness (5.4%), nutritional deficiency (5.0%), parasitic illness (5.0%), congenital disorders (2.5%), and human-associated trauma (0.4%). Pups were the most common age class (87.4%) amongst mortalities and predominantly died of an infectious process (62.5%). Phocid herpesvirus-1 infection was identified in 18.9% of the mortalities, with the highest prevalence occurring in 2019 (30.8%). Fungal disease was detected in six seals: three cases of pulmonary mycosis due to Cryptococcus gattii and three cases consistent with mucormycosis. In six cases, mortality was attributed to congenital disorders. Two of these cases involved axial skeletal malformities that are not currently described in the literature. This is the first study to describe the causes of mortality in harbor seals undergoing rehabilitation in British Columbia.

Our understanding of wildlife multihost pathogen transmission systems is often incomplete due to the difficulty of observing contact between hosts. Understanding these interactions can be critical for preventing disease-induced wildlife declines. The proliferation of high-throughput sequencing technologies provides new opportunities to better explore these cryptic interactions. Parelaphostrongylus tenuis, a multihost parasite, is a leading cause of death in some moose (Alces alces) populations threatened by local extinction in the midwestern and northeastern US and southeastern Canada. Moose contract P. tenuis by consuming infected gastropod intermediate hosts, but little is known about which gastropod species moose consume. To gain more insight, we used a genetic metabarcoding approach on 258 georeferenced and temporally stratified moose fecal samples collected May–October 2017–20 from a declining population in the north-central US. We detected moose consumption of three species of gastropods across five positive samples. Two of these (Punctum minutissimum and Helisoma sp.) have been minimally investigated for the ability to host P. tenuis, while one (Zonitoides arboreus) is a well-documented host. Moose consumption of gastropods documented herein occurred in June and September. Our findings prove that moose consume gastropod species known to become infected by P. tenuis and demonstrate that fecal metabarcoding can provide novel insight on interactions between hosts of a multispecies pathogen transmission system. After determining and improving test sensitivity, these methods may also be extended to document important interactions in other multihost disease systems.

Helminths, in particular eyeworms (Oxyspirura petrowi) and cecal worms (Aulonocephalus pennula), may be a factor influencing northern bobwhite (Colinus virginianus) populations in Texas. Previous research has shown a discrepancy in helminth infections between the Rolling Plains and Rio Grande Plains of Texas, US, potentially caused by differences in intermediate host distribution and abundance. We explored an alternative hypothesis centered on plant diversity, given that many plants possess phytochemicals with anthelmintic properties. We predicted that plant diversity would be greater and bobwhite diet more diverse in the Rio Grande Plains than the Rolling Plains, which in turn would potentially expose bobwhites to more plants with anthelmintic properties and therefore result in lower parasite prevalence and intensity. We conducted a literature review of plant diversity, anthelmintic plants, and bobwhite diet in Texas to explore this hypothesis. We also quantified the relationship between helminth prevalence in bobwhites and latitude. We documented trends for higher plant species richness, greater number of anthelmintic plants, and more diverse bobwhite diet in the Rio Grande Plains compared to the Rolling Plains. In addition, we documented a trend for increasing helminth prevalence with latitude for eyeworms but not cecal worms. Our study provides circumstantial evidence supporting the plant-diversity hypothesis and warrants experimental testing.

Plague, caused by Yersinia pestis, is a widespread threat to endangered black-footed ferrets (Mustela nigripes) and their primary prey, prairie dogs (Cynomys spp.). Wildlife biologists most commonly manage plague using insecticides to control fleas, the primary vectors of Y. pestis. We tested edible baits containing the insecticides lufenuron and/or nitenpyram in prairie dogs. During a laboratory study, we treated 26 white-tailed prairie dogs (Cynomys leucurus) with lufenuron at 300 mg/kg body mass. All animals remained clinically healthy over the 9 wk monitoring period. Although serum lufenuron concentrations were >130 ppb in two treatment groups at week 1, concentrations declined to ≤60 ppb after 3 wk in non-torpid prairie dogs and after 7 wk in torpid prairie dogs. In a field experiment, we tested baits containing a combination of 75 mg lufenuron and 6 mg nitenpyram, respectively, in black-tailed prairie dogs (Cynomys ludovicianus). We uniformly distributed baits at 125 baits/ha on two plots (treated once) and 250 baits/ha on two plots (each treated twice 4.4 wk apart). Following treatments, flea abundance increased on prairie dogs and remained stable in burrows. Our findings indicate that baits containing lufenuron and nitenpyram, at the reported treatment rates, are ineffective tools for flea control on prairie dogs. Future experiments might evaluate efficacy of higher doses of lufenuron and nitenpyram, and repetitive treatments at differing intervals over time to evaluate potentially therapeutic treatments.

Chagas disease, a significant public health concern in the Americas, is caused by a protozoan parasite, Trypanosoma cruzi. The life cycle of T. cruzi involves kissing bugs (Triatoma spp.) functioning as vectors and mammalian species serving as hosts. Raccoons (Procyon lotor) and opossums (Didelphis virginiana) have been identified as important reservoir species in the life cycle of T. cruzi, but prevalence in both species in the southeastern US is currently understudied. We quantified T. cruzi prevalence in these two key reservoir species across our study area in South Carolina, US, and identified factors that may influence parasite detection. We collected whole blood from 183 raccoons and 126 opossums and used PCR to detect the presence of T. cruzi. We then used generalized linear models with parasite detection status as a binary response variable and predictor variables of land cover, distance to water, sex, season, and species. Our analysis indicated that raccoons experienced significantly higher parasite detection rates than Virginia opossums, with T. cruzi prevalence found to be 26.5% (95% confidence interval [CI], 20.0–33.8) in raccoons and 10.5% (95% CI, 5.51–17.5) in opossums. Overall, our results concur with previous studies, in that T. cruzi is established in reservoir host populations in natural areas of the southeastern US.

The tapeworm Echinococcus multilocularis is an emerging pathogen of significance to human and animal health in Canada, yet little is known about key rodent intermediate hosts in local urban ecosystems. In Europe, invasive muskrats (Ondatra zibethicus) are an important indicator intermediate host species; however, the role of this semiaquatic rodent in the ecology of E. multilocularis is undetermined in the North American context. We examined 93 muskrats that were livetrapped in the spring of 2017 within Calgary, Alberta, Canada, for the presence of E. multilocularis infection. The objectives of this study were to 1) diagnose alveolar echinococcosis using macroscopic assessment, histopathology, and molecular analyses; 2) quantify infection severity; and 3) assess host demographic risk factors for infection. Macroscopic cysts consistent with alveolar echinococcosis were present in 24% of muskrats (22/93). Most individuals had hepatic cysts; however, cysts were also occasionally detected in the mesentery, reproductive organs, omentum, peritoneum, spleen, diaphragm, lung, or kidney. The mean number of cysts per liver was 2.1 (range, 1–4). We examined hepatic cysts from 18 individuals using histology; all had lesions compatible with alveolar echinococcosis. Protoscoleces, indicative of patent infections, were present in 14/18 (78%). No demographic risk factors (sex, body condition, body mass) were significantly associated with infection. Muskrats in the North American context are competent intermediate hosts with high infection prevalence and may play an important role in the ecology of this emerging parasite.

Waterfowl infected with avian influenza A viruses (IAVs) shed infectious virus into aquatic environments, providing a mechanism for transmission among waterfowl, while also exposing the entire aquatic ecosystem to the virus. Aquatic invertebrates such as freshwater snails are likely exposed to IAVs in the water column and sediment. Freshwater snails comprise a significant portion of some waterfowl species' diets, so this trophic interaction may serve as a novel route of IAV transmission. In these experiments, tadpole snails (Physa spp.) were exposed to a low-pathogenicity IAV (H3N8) to determine whether snails can accumulate the virus and, if so, how long virus persists in snail tissues. Snail tissues were destructively sampled and tested by reverse-transcription quantitative real-time PCR. Our experiments demonstrated that tadpole snails do accumulate IAV RNA in their tissues, although at low titers, for at least 96 h. These results indicate that it may be possible for IAV transmission to occur between waterfowl via ingestion of a natural invertebrate prey item; however, the time frame for transmission may be limited.

Disease surveillance testing for emerging zoonotic pathogens in wildlife is a key component in understanding the epidemiology of these agents and potential risk to human populations. Recent emergence of SARS-CoV-2 in humans, and subsequent detection of this virus in wildlife, highlights the need for developing new One Health surveillance strategies. We used lymph node exudate, a sample type that is routinely collected in hunter-harvested white-tailed deer (WTD, Odocoileus virginianus) for surveillance of chronic wasting disease, to assess anti-SARS-CoV-2 neutralizing antibodies. A total of 132 pairs of retropharyngeal lymph nodes collected from Nebraska WTD harvested in Nebraska, US, in 2019 (pre–SARS-CoV-2 pandemic) and 2021 (post–SARS-CoV-2 pandemic) were tested for SARS-CoV-2 with reverse transcription PCR. Thereafter, exudates obtained from these same lymph nodes were tested for SARS-CoV-2 neutralizing antibodies using a surrogate virus neutralization test. Neutralizing antibodies were detected in the exudates with high diagnostic specificity (100% at proposed cutoff of 40% inhibition). Application of this testing approach to samples collected for use in other disease surveillance activities may provide additional epidemiological data on SARS-CoV-2 exposure, and there is further potential to apply this sample type to detection of other pathogens of interest.

One of the major threats for the massive loss in global amphibian diversity is chytridiomycosis, caused by chytrid fungi Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal). Following its discovery in 2013, Bsal has emerged as a severe threat to the global survival of urodelans. In 2018, a study reported a high prevalence of Bsal (65.6%) in the Hong Kong newts (Paramesotriton hongkongensis, Near Threatened) of a southern China population adjacent to Hong Kong (HK). Uncertainty regarding the Bsal infection status of P. hongkongensis inhabiting HK raised deep concern over the risk of introducing Bsal from that population. We screened the skin swabs from wild individuals of P. hongkongensis, 15 sympatric amphibian species, and 16 imported amphibian species in HK for chytrids. We found that both Bsal and Bd occur in low prevalences in P. hongkongensis (Bsal 1.7%, 5/293; Bd 0.34%, 1/293), Hong Kong cascade frog, Amolops hongkongensis, family Ranidae (Bsal only, 5.26%, 1/19), and Asian common toad, Duttaphrynus melanostictus, family Bufonidae (Bsal only, 5.88%, 1/17), populations of HK, with infected individuals being asymptomatic, suggesting a potential role of these species as reservoirs of Bsal. Conversely, Bd, but not Bsal, was present on 13.2% (9/68) of imported amphibians, indicating a high chytrid introduction risk posed by international amphibian trade. Long-term surveillance of the presence of Bd and Bsal in wild and captive amphibians would be advisable, and we recommend that import and export of nonnative chytrid carriers should be prevented, especially to those regions with amphibian populations naïve to Bd and Bsal.

Rocky Mountain spotted fever (RMSF), caused by the bacterium Rickettsia rickettsii, is a re-emerging tick-borne zoonosis in North America, with hundreds of human fatalities in multiple outbreaks in northern Mexico and the southwestern US in the past few decades. Free-roaming dogs are key because they are reservoirs for the pathogen and the main hosts of the brown dog tick (Rhipicephalus sanguineus), which vectors RMSF in this region. Because coyotes (Canis latrans) can be infected with R. rickettsii and infested with Rh. sanguineus, we hypothesized that space sharing among dogs and coyotes could enhance disease risks. In summer 2021, we captured and sampled 11 coyotes at two sites in Baja California, Mexico, near population centers with human cases of RMSF, and fitted seven individuals with GPS logging collars. We also tested tissue samples, sera, and ectoparasites for DNA of R. rickettsii with PCR and used serology to detect antibodies to R. rickettsii. Finally, we deployed an array of cameras to document dog-coyote interactions. Mean home range size was 40.37 km². Both GPS and camera data showed considerable home range overlap both between individual coyotes and between coyotes and dogs. Coyotes were active in areas where dogs occur including the domestic interface surrounding human settlements. Although none of our samples were positive for R. rickettsii on PCR, 72.7% (8/11) of the samples were seropositive with titers ≥64. Our data confirm shared space use and risk of shared parasites and disease between coyotes and dogs.

Rabies is an acute progressive encephalitis caused by infection with rabies viruses, with reservoirs among bats and mesocarnivores, but all mammals are susceptible. Despite its distribution and abundance, cases of rabies are much less common in rodents and lagomorphs. Familiarity with current rabies prevalence data is important for informed decisions on human postexposure prophylaxis after rodent and lagomorph bites. This study is an update of rabies cases reported in rodents and lagomorphs in the US from 2011 to 2020. Rabies reports were collected passively from laboratory testing agencies in the US and Puerto Rico from 2011 to 2020. Descriptive analysis was conducted to determine the percent positivity of rabies cases by species. A total of 401 cases of rabies in rodents and lagomorphs were reported from 2011 to 2020. Most reported cases were in groundhogs (Marmota monax), representing >90% of cases, and the trend closely aligned with rabies in raccoons (Procyon lotor). In any given year, the percent positivity of rabies in rodents and lagomorphs was <2.5%, and the trend of percent positivity from 2011 to 2020 was stable. Groundhog and North American beaver (Castor canadensis) percent positivity was significantly higher than the rest of the rodents and lagomorphs. Most rabies cases occurred during the months of May–September. Documented cases of rabies in rodents and lagomorphs are generally rare, but with variation between species. Groundhogs and North American beavers had rabies percent positivity similar to high-risk species, such as bats and raccoons, and constituted 97% of all rodent and lagomorph positive cases. Since 1993, the trend in rabies cases in groundhogs has significantly declined. These results can be used to help inform public health officials on rodent and lagomorph prevention and control efforts, as well as rabies postexposure prophylaxis.

Characterizing host factors affecting individual health can be important in the conservation of many chelonians, including the Blanding's turtle (Emydoidea blandingii). However, many routine clinical pathology tests do not reliably detect differences in health status in reptiles. The erythrocyte sedimentation rate (ESR) has been shown to characterize inflammation in many species, including tortoises, and may be useful in assessing Blanding's turtles. The purpose of our study was to evaluate two methods of ESR measurement in free-ranging Blanding's turtles. Sixty Blanding's turtles captured at two sites in Illinois received a complete physical examination, and blood was collected for determination of packed cell volume, total solids, and ESR with both microhematocrit tubes and commercial kits (Winpette). Method agreement was assessed with Passing-Bablok regression. Associations between ESR and demographic, environmental, and health factors were determined by linear regression. The microhematocrit tube method proportionately overestimated ESR compared with the Winpette. With the use of both measurement methods, ESR was significantly different between study sites, higher in adult Blanding's turtles, and higher in females that were gravid compared with those that were not. ESR was also negatively associated with packed cell volume. ESR values in Blanding's turtles are comparable to other reptiles, and although microhematocrit tube and Winpette results are not interchangeable, their associations with biological predictors are similar, and either method has the potential to be used with separate reference intervals to assess turtles for inflammatory conditions.

Elaeophora schneideri is a filarial nematode of North America that occasionally infects aberrant ruminant hosts such as moose (Alces alces). The role E. schneideri plays in clinical morbidity or mortality of moose remains uncertain. We sampled predominantly hunter-killed adult moose (n=127) to characterize the spatial patterns of prevalence and intensity of worms in carotid arteries of moose in Montana. We compared prevalence and intensity of E. schneideri within these moose to a separate sample of adult moose that died of health-related causes (n=34). We found lower prevalence in northwest Montana (0.06) than in the remainder of the state (0.42). We also found both higher prevalence of E. schneideri and higher intensity to be correlated with increased probability of health-related mortality. Our results suggest presence and intensity of E. schneideri correlate with mortality of moose, although the mechanisms of mortality remain uncertain.

Respiratory disease is a significant barrier for bighorn sheep (Ovis canadensis) conservation, and a need remains for management options in both captive and free-ranging populations. We treated Mycoplasma ovipneumoniae infection in six bighorn lambs and five bighorn yearlings at two captive research facilities with twice daily oral doxycycline for 8 wk or longer. Doses of 5 mg/kg twice daily mixed in formula for lambs and 10 mg/kg twice daily mixed in moistened pellets for older lambs and yearlings were tolerated well with minimal side effects. All animals in this case report remain Mycoplasma ovipneumoniae free over 2 yr later. Further evaluation is warranted to confirm efficacy of this therapeutic approach.

Twenty-four American white ibis (Eudocimus albus) nestlings were collected in Florida (USA) on 17 April 2017 to establish a captive flock. On 7 May 2017, three birds died suddenly, following severe lethargy, hemorrhaging from the mouth and nares, anorexia, and production of bright-green colored feces. An additional ibis with delayed growth and pathological fractures was euthanized 18 May 2017. Severe ventriculitis associated with Macrorhabdus ornithogaster was noted in all four birds, bacterial sepsis was confirmed in one bird by culture and histologic examination, and bacterial endotoxemia was suspected in two birds based on gross and histologic examination, but no bacteria were isolated from these birds. Birds also had vitamin E liver levels consistent with coagulopathy previously described in pelicans. We sampled feces from 91 adult, free-living, healthy ibis in Florida in July 2017 and found 71% were shedding organisms with morphologic characteristics consistent with Macrorhabdus sp. Molecular characterization of the ibis-origin M. ornithogaster showed it was phylogenetically related to numerous M. ornithogaster sequences. It is unknown if M. ornithogaster infection resulted in clinical disease as a result of dietary or stress-related dysbiosis, or other factors. Macrorhabdus-associated disease has not previously been confirmed in wading birds. We discuss potential associations of gastric M. ornithogaster infection with morbidity and mortality in these cases and highlight the need for additional studies on this pathogen in free-living birds.

A Eurasian strain of H5N1 highly pathogenic avian influenza virus (HPAIV) was first detected in North America in December 2021 and has since been confirmed in numerous wild and domestic avian species. In April 2022, 41 Wild Turkeys (Meleagris gallopavo) were found dead in Johnson County, Wyoming, USA adjacent to a property with confirmed HPAIV in a backyard poultry flock. Oropharyngeal swabs were collected from 11 of the 41 turkeys and necropsy was performed on seven. Avian influenza virus RNA was detected in all 11 turkeys by real-time reverse-transcription PCR. Acute, multiorgan necrosis was observed grossly and identified in all seven turkeys evaluated by histopathology, most consistently in the lung, spleen, liver, gastrointestinal tract, and gonads. Lesions indicate high virulence of subclade 2.3.4.4b H5N1 HPAIV in Wild Turkeys, with infections presenting as clusters of acute mortality. Although documented cases of HPAIV in Wild Turkeys are rare, these findings signify a risk of spillback from domestic poultry, which may be heightened by the recent rise in backyard poultry ownership and the use of peridomestic habitat by wild birds. Additional research is needed to better understand the risk of disease transmission at the interface of Wild Turkeys and backyard poultry and the potential conservation and management implications of HPAIV in wild gallinaceous birds.

The frequency of arthropod-borne viral disease in naïve hosts is subject to change based on complex interactions among vector, host, virus, and external factors (e.g., climate). Thus, continual monitoring for both disease susceptibility and host infection dynamics is needed, especially for viruses that have proven detrimental to the health of wildlife hosts of conservation concern. The Greater Sage-grouse (Centrocercus urophasianus) is a gamebird of ecological and economic importance in the western United States for which population declines have led to a Near Threatened conservation status. Although these declines have mainly been attributed to habitat loss, West Nile virus (WNV) also poses a threat, with regional transmission potentially fueled by anthropogenic landscape alterations that may facilitate mosquito breeding. With limited WNV monitoring in Greater Sage-grouse after recognition of high susceptibility to mortality early after its initial detection in the western United States, the potential long-term impacts of WNV on this species are poorly understood. We used the plaque reduction neutralization test of filter paper strip–eluted sera to assess for anti-WNV antibodies, indicating prior infection, in opportunistically collected samples. From 2020 to 2022, 85 Greater Sage-grouse in Wyoming were sampled; none had anti-WNV antibodies. This result corroborates findings of previous studies documenting low seroprevalence. With the tenuous conservation status of the species, all potential population health risks should be considered in future management strategies, especially in the face of changing climate and landscapes.

We identified by light microscopy micro- and macrogametes and oocysts of renal coccidia in 78 of 220 (35.5%) Northern Gannets (Morus bassanus) from the western North Atlantic population. This infection was not considered clinically significant in any of the affected birds, although the potential effect of this parasite in breeding colonies, particularly among nestlings, is unknown. Analysis of the 18S rRNA gene from frozen renal tissue by PCR and subsequent sequencing revealed 95.6% identity with Eimeria auritusi from Double-crested Cormorants (Phalacrocorax auritus), suggesting a novel Eimeria sp. in the Northern Gannets.

Since 2001, high-mortality outbreaks of border disease (BD) have negatively affected populations of Pyrenean chamois (Rupicapra pyrenaica pyrenaica). Studies in the affected areas determined that sympatric wild ruminants did not seem to have an epidemiologic role in the circulation of border disease virus (BDV). However, the recent increase in European mouflon (Ovis aries musimon) densities might enhance the risk of pathogen transmission among chamois and mouflons. We conducted a serologic and virologic investigation of BDV in European mouflon from the Spanish Pyrenees, with the aim of determining potential changes in the role of this species in BDV epidemiology. From 2018 to 2022, we detected antibodies against BDV in 31/185 (16.7%) animals but did not detect BDV RNA in any spleen sample (0/65). These results indicate that BDV infection is occurring in these mouflon populations to a greater extent than previously described, which could shift the current understanding of BD epidemiology in the Pyrenees and cause an unpredictable effect on both chamois and mouflon populations. Further studies on the molecular identification of BDV in mouflon and chamois are required to better understand the contribution of mouflon in the epidemiology of BD.

At a visit to an unfenced desert conservation reserve in Dubai, United Arab Emirates in February 2022, severe skin disease was noted among resident Arabian oryx (Oryx leucoryx), manifesting as dark grayish to black bark-like thickened skin. Between and 45% and 60% of the oryx showed unrest and pruritus. Sarcoptes scabiei was detected at necropsy of six adult animals. Treatment with ivermectin-medicated pellets at 0.3 mg/kg estimated body weight over two periods of 7 d with a 14-d interval between treatments resulted in improved body and skin condition and hair regrowth. Although severe hyperkeratosis was still present shortly after treatment, no live Sarcoptes mites were found in parasitological examination of skin scrapings of two necropsied animals. By 4 mo post treatment the oryx had returned to normal body condition and coat condition.

As threats to amphibian health increase, there is a growing need for diagnostic tools to assess and monitor their health status. Plasma protein electrophoresis has proven to be useful in other nonmammalian species. It enables quantification of protein fractions in plasma that may be altered in various disease processes, and is therefore useful in narrowing down differential diagnoses and detecting inflammation, in combination with other modalities such as biochemical and hematologic testing. The amphibian electrophoretogram must be defined before baseline reference intervals are obtained across species. Agarose gel electrophoresis was performed on plasma samples collected from presumed clinically normal individuals of one anuran and six urodelans: Osteopilus septentrionalis (n=2), Gyrinophilus porphyriticus (n=1), Notophthalmus viridescens (n=1), Eurycea guttolineata (n=2), Amphiuma tridactylum (n=2), Cryptobranchus alleganiensis (n=5), and Siren lacertina (n=6). The electrophoretograms varied in number of fractions between each species; however, the number of fractions was consistent within a species. An albumin migrating fraction was consistently observed in all species. A prealbumin migrating fraction was identified in species that primarily use organs other than skin for respiration. This study provides preliminary examples of a normal plasma protein electrophoretogram for seven amphibian species. Further studies quantifying reference intervals and identification of protein fractions will help establish protein electrophoresis as a useful tool in amphibian health investigations.

A Common Loon (Gavia immer) was found recumbent at Island Beach State Park, New Jersey, US, and euthanized. Necropsy revealed a caseous mass in the kidney, from which bacteria were isolated and phenotypically and molecularly identified as Edwardsiella tarda.

A cutaneous mass in a free-ranging brush rabbit (Sylvilagus bachmani) was composed of neoplastic spindle to polygonal cells with multinucleated giant cells, which were positive for CD204 and negative for smooth muscle actin and desmin. Histiocytic sarcoma with giant cells was diagnosed; this neoplasm has not been reported previously in free-ranging lagomorphs.

Ehrlichia minasensis, a pathogen of cattle in Brazil, was detected in genomic DNA of a female Dermacentor albipictus feeding on a moose (Alces alces) in west-central Saskatchewan, Canada. This bacterium has not previously been confirmed in ticks in Canada. It is unknown whether moose are reservoirs for E. minasensis.

A free-living Bald Eagle (Haliaeetus leucocephalus) displayed acute onset neurologic signs. Postmortem analysis of adipose tissue identified desmethylbromethalin, the active metabolite of bromethalin. Antemortem signs, detection of desmethylbromethalin, and results of other diagnostics support the possibility of secondary bromethalin toxicosis. Investigation of bromethalin's potential risk to wildlife is critically needed.

Book reviews express the opinions of the individual authors regarding the value of the book's content for Journal of Wildlife Diseases readers. The reviews are subjective assessments and do not necessarily reflect the opinions of the editors, nor do they establish any official policy of the Wildlife Disease Association.