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Free-living wildlife across Africa is found across expansive rangelands, frequently interacting with pastoral communities, their livestock, and domestic dogs (Canis familiaris). African wildlife populations are threatened by development, poaching and disease. Infectious diseases have caused significant declines, sabotaging conservation efforts. Canine distemper virus (CDV) infections have increased in incidence in wildlife over the past four decades. Sympatric domestic dogs have been presumed to be the reservoirs of the virus for wildlife. A systematic review using Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines was carried out to investigate CDV infections in wildlife in Africa, to 1) analyze the conservation concerns associated with the disease, 2) identify the dynamics of the virus across different ecoregions, and 3) ascertain the source of the virus for free-living wildlife. The database searches identified 65 articles relevant to the study questions and an additional 43 valuable for wider discussion of the topic area. Canine distemper outbreaks were reported to occur in wildlife in six African countries, with mortality rates between 30% and 94% across all species affected. Eleven wildlife species were identified as susceptible, 64% of which (7/11) are classified as threatened by the International Union for Conservation of Nature. Disease dynamics varied between ecoregions because of differences in land use; virus strains; climate change and concurrent infections; ecotones; domestic and wildlife population densities; wildlife monitoring capacity; and wildlife movement. Nine countries reported outbreaks in domestic dog populations in or near wildlife habitats, but none reported confirmed transmission to wildlife. Of 23 reports investigating the role of domestic dogs as CDV reservoirs, 14 (61%) concluded that domestic dogs acted as either reservoirs or sources of CDV for wildlife, four (17%) did not identify dogs as reservoirs, and five (22%) were not sure of the role played by domestic dogs. This review highlights the importance of integrating active CDV surveillance in wildlife conservation programs.
Respiratory rate (mean number of breaths per minute) and respiratory interval (mean time between breaths) can offer insight into a diving mammal's activity state, metabolic rate, behavior, and synchronization due to social cohesion. Also, respiratory rate can reflect an individual animal's health and has the potential to be an informative remotely assessed health metric for monitoring individual animal health in endangered whale species and populations such as southern resident killer whales (Orcinus orca). Using data collected from noninvasive, land-based theodolite tracking, we analyzed swimming speed and surfacing intervals (i.e., mean dive time or mean time between breaths) from 20,613 surfacings of 98 individuals from two populations of the fish-eating, resident killer whale ecotype, namely, one growing (northern resident) and one declining and endangered (southern resident) population. Focal animal sampling was used to measure behavior of individuals of known age and sex in various activity states. Our objective was to evaluate variability and generate normal ranges for respiratory intervals and swimming speeds for killer whales of the Northeast Pacific Ocean resident, fish-eating ecotype to identify baseline respiratory intervals. We found that median respiratory intervals for fish-eating killer whales were between 26 and 29 s for all activity states and that swimming speeds varied by activity state. Median swimming speeds were similar for foraging and traveling (1.6 and 1.7 m/s, respectively), but were significantly slower during resting (1.1 m/s) and social activity (1.3 m/s) states. Three southern resident killer whales in poor body condition (had body condition scores in the lowest 20th percentile of the population) swam at reduced speeds and had shorter median respiratory intervals than outwardly healthy whales of similar age and sex. Respiratory rates, respiratory intervals, and swimming speeds are valuable remotely sensed metrics of health for free-swimming killer whales, especially when combined with other metrics as is the standard in veterinary examinations.
Alexis Davidson, Michelle W. Kendall, Maura Ryan, Kayla Ladez, Samantha Bradley, Carley Lionetto, William Graser, Gary Glowacki, Daniel Thompson, Richard B. King, Callie K. Golba, Kaitlin Moorhead, Laura Adamovicz, Matthew C. Allender
Blanding's turtles (Emydoidea blandingii) are a species of conservation concern throughout their natural range. Headstarting is a common chelonian conservation technique in which neonates are reared in managed-care settings before release, but health assessments are rarely incorporated. From 2020 to 2021 we assessed headstarted turtle health pre-release and 1 mo, 1 yr, and 2 yr after release using physical examination, hematology, plasma biochemistry, protein electrophoresis, and pathogen detection in three Illinois counties. Results were compared to wild-reared juveniles in the same habitats. Overall, 767 assessments from 561 turtles were included. Wild-reared and 2 yr post-release headstarts had higher incidence of hemoparasites, asymmetrical nares, and increased creatine kinase and aspartate aminotransferase activities (P<0.05) compared to all other groups. Erythrocyte sedimentation rate and heterophil:lymphocyte ratio were greater, while total leukocyte and lymphocyte counts were lower (P<0.05) in pre-release headstarts compared to wild-reared juveniles. Total solids, albumin, and beta globulins were higher, while the calcium:phosphorous ratio was lower (P<0.05) in pre-release headstarts and wild-reared juveniles vs. other groups. Bile acid levels were highest in pre-release headstarts (P<0.05). Body condition and gamma globulins increased following release, while alpha globulins and the albumin:globulin ratio decreased following release (P<0.05). Two pre-release and one post-release headstart tested positive for Emydomyces testavorans, one post-release headstart was positive for Mycoplasmopsis sp., and nine post-release turtles were positive for adenoviruses. Overall, rearing conditions have a profound and temporally dynamic impact on Blanding's health assessment parameters. Future studies should evaluate long-term impacts on morbidity and mortality to support positive health status and conservation outcomes.
Dredging is commonly used to maintain navigational channels in freshwater lakes such as Lake Erie, and the dredged material may be discarded in confined disposal facilities (CDFs). The effects of these CDFs on wildlife health are largely unknown. We compared health assessments of painted turtles (Chrysemys picta) at two sites in southwestern Lake Erie, Ohio, USA in May 2022: CDF for dredged material (n=27), and a protected coastal marsh (PCM; n=24). Each turtle underwent a physical examination, blood collection for hematology and plasma biochemistry profiles, and testing for Chlamydia spp., herpesviruses, ranavirus (frog virus 3), and Mycoplasmopsis spp. via oral and cloacal swabs. Six turtles were positive for Chlamydia spp. (11.8%; 95% confidence interval [CI]: 4.4%–23.9%), two from the CDF and four from the PCM. One Chlamydia-positive turtle was co-infected with herpesvirus (2.0%; 95% CI: 0%–10.5%) with 96.3% homology with emydid herpesvirus. No ranavirus or Mycoplasmopsis species were detected (0%, 95% CI: 0%–6.7%). Turtles captured from the CDF had significantly higher heterophil percentages, heterophil/lymphocyte ratios, and glucose levels, but significantly lower total protein and calcium/phosphorus ratios than turtles from PCM. Turtles living in the CDF were hyperglycemic, potentially indicating increased stress levels compared to the normoglycemic turtles from PCM. As humans continue to alter wetland habitats, the impact of anthropogenic sites such as CDFs on freshwater chelonian health and welfare should be monitored.
Damani N. Bryant, Roxanne J. Larsen, Kristin J. Bondo, Andrew S. Norton, Andrew J. Lindbloom, Steven L. Griffin, Peter A. Larsen, Tiffany M. Wolf, Stuart S. Lichtenberg
Sensitive and specific antemortem diagnostic tests are a prerequisite for effective management of chronic wasting disease (CWD). Paired with readily accessible samples that accurately reflect CWD status, the real-time quaking-induced conversion (RT-QuIC) assay has the potential to enable more effective CWD surveillance and interventions. We evaluated the feasibility of RT-QuIC as a CWD diagnostic test using 6-mm ear tissue biopsies from elk (Cervus canadensis). First, we evaluated the effect of ear spatial location on seeding activity. We observed an effect of ear punch spatial location on the amyloid formation rate (AFR): Samples collected from the periphery of the ear evidenced a statistically significant increase in AFR relative to ear punches from the ventral midline. Gross microdissection of an ear pinna suggested that there was more small nerve innervation around the periphery of the ear. Second, we evaluated the diagnostic sensitivity, specificity, and predictive value of RT-QuIC using ear punches from elk that had been previously diagnosed via ELISA testing. We evaluated the impact of nonstatistical and statistical approaches on diagnostic accuracy. Specificity and positive predictive value were perfect when statistical analyses were used to evaluate the binomial distribution (CWD positive versus CWD negative) of the data. Conversely, sensitivity and negative predictive value were modest, independent of the application of statistical analysis, indicating that RT-QuIC may be susceptible to false-negative data in this context. Taken together, our data support the idea that RT-QuIC, when paired with US Department of Agriculture–approved diagnostic tests, may provide more time to stakeholders for making major management decisions.
Polar bear (Ursus maritimus) life history is intimately associated with the distribution of sea ice and their prey in Arctic ecosystems. These ecosystems are changing in response to climate warming, resulting in the increased prevalence of pathogens in polar bears. Erysipelothrix rhusiopathiae has a long history of infection in domestic species and more recently in wildlife in the Canadian Arctic. As a result of increasing reports of E. rhusiopathiae causing morbidity and mortality in Arctic terrestrial mammals, we tested the seroprevalence of E. rhusiopathiae in Beaufort Sea polar bears sampled in 1985–87, 1992, 1994, and 2003–11. Our sample of 180 polar bears (117 females, 61 males, two unknown) with a median age of 9 yr (range 1–26 yr) had a seropositivity of 27.2% (49/ 180 individuals). We used binomial logistic regressions to investigate biotic and abiotic factors that may be linked to seropositivity. The resulting top model found that increased predation on adult ringed seals (Pusa [Phoca] hispida) and negative winter Arctic Oscillation Index (AOI) years were associated with a higher probability of seropositivity. Ringed seals may be a reservoir for E. rhusiopathiae via their consumption of infected prey, as the pathogen can persist in marine fish, molluscs, and crustaceans. Negative winter AOIs in our data set reflected high ice volume years, which reduced ringed seal natality, resulting in fewer seal pups available as prey. Our results suggest that exposure to E. rhusiopathiae in Beaufort Sea polar bears is modulated by a predator–prey mechanism.
Infectious diseases can have detrimental effects on wildlife populations, particularly those that persist at small sizes, have low genetic diversity, and are affected by fragmented habitat. One such example is the endangered Florida panther (Puma concolor coryi), which has been intensively managed since the early 1980s, with the current population ranging between 120 and 230 individuals. For more than three decades, panthers have been captured, demographics recorded, and blood samples collected to monitor for multiple infectious diseases; however, an updated comprehensive study of many of these pathogens has not occurred since 1991. Our goal was to identify temporal patterns and spatial clustering in seroprevalence; determine if the pathogens of interest tend to co-occur; and describe relationships between an individual's genetic assignment (admixed or canonical) and seropositivity. We analyzed serology data for eight pathogens representing different modes of transmission (direct, indirect, vector borne) and infection duration (acute, chronic) from 232 panthers collected between 1992 and 2017. Panthers held consistently high seropositivity for feline calicivirus (62.3%) and panleukopenia virus (79.7%) throughout the study, whereas feline herpesvirus and feline leukemia virus were at lower prevalence (3.1% and 2.4%, respectively), although neither had been noted prior to 1992. Panthers were frequently seropositive for canine distemper virus and feline immunodeficiency virus, and seroprevalence fluctuated through time. West Nile virus seropositivity increased over the study period following its introduction in North America in 1999. Panthers were consistently negative for feline coronavirus, which causes feline infectious peritonitis. Genetics and demographics (sex and age) had little influence on serostatus, and coexposure among pathogens did not tend to occur. Both feline immunodeficiency virus and feline leukemia virus appeared to have spatial clusters of seropositive individuals. Our findings enhance the understanding of pathogen exposure in panthers, informing and supporting ongoing surveillance efforts for timely detection and management of potential disease threats in vulnerable populations.
Julien Hirschinger, Sylvain Larrat, Guillaume Le Loc'h, Pascal Arné, Philippe Gourlay, Claire Le Moal, Laure Prevost, Philippe Berny, Eve Ramery, Lionel Zenner, Thomas Rambaud, Pauline Hubert, Emmanuelle Gilot-Fromont, Karin Lemberger
The European hedgehog (Erinaceus europaeus), common in rural and suburban environments, is perceived as declining within its native range, prompting conservation concerns. This study of hedgehogs admitted to a French rehabilitation center aimed to identify causes of death, detect potential emerging diseases, and systematically screen dead hedgehogs for toxicants and hemopathogens. Using clinical information, necropsy examination, and ancillary testing in 159 dead hedgehogs, we identified the primary cause of death of 92% of them. The leading causes of death were impaired general condition (30%); bacterial infections (26%), frequently caused by Salmonella Enteritidis; and trauma (20%). Additional factors contributing to death were identified in 78%, including a high proportion with significant parasite infestations. Toxicologic screening revealed that 42% of hedgehogs had been exposed to anticoagulant rodenticides, including 6.4% hedgehogs with levels compatible with acute intoxication. These hedgehogs were also exposed to trace metals, especially lead, but no pesticides residues were detected. Hemopathogen screening revealed a low diversity and prevalence of blood pathogens with 3.6, 2.9, and 2.9% individuals infected with Anaplasma phagocytophilum, Mycoplasma turicensis, and Mycoplasma wenyonii, respectively. The variety of diagnoses suggests that there is no unique prominent or emerging disease responsible for the mortality of these hedgehogs. This study also highlighted the high exposure of hedgehogs to various toxicants. To further investigate the extent and causes of population declines, health information issued from several centers should be combined with demographic data as well as ecologic assessments on the availability and quality of natural resources.
Butorphanol-azaperone-medetomidine (BAM) is commonly used for white-tailed deer (Odocoileus virginianus) immobilization in captive and free-ranging populations. It is a federally regulated controlled substance requiring stringent regulatory compliance, complicating field application. A prescription-only drug combination, nalbuphine-medetomidine-azaperone® (NalMed-A) provides a less-regulated alternative for use by wildlife professionals. Efficacy and safety of these drug combinations for immobilization of deer have not been compared in a controlled trial, and reports of dose-specific effects of NalMed-A on white-tailed deer physiology are lacking. Additionally, residual effects of these drugs on deer behavior, food consumption, and stress response have not been reported. In February through April 2021, we immobilized 30 captive female, adult white-tailed deer in three treatment groups (n=10 each). Hand-injected doses were 1.5 mL BAM intramuscularly (IM; 41.0 mg butorphanol, 13.6 mg azaperone, 16.4 mg medetomidine), 1.5 mL NalMed-A IM (60.0 mg nalbuphine, 15.0 mg medetomidine, 15.0 mg azaperone), and 2.0 mL NalMed-A IM (80.0 mg nalbuphine, 20.0 mg medetomidine, 20.0 mg azaperone). We compared quality of immobilizations and reversals and times to induction and reversal among treatments, collected biological samples to measure stress hormones and blood gases, and conducted observations to determine treatment-related variations in behaviors. When an effective dose was administered, both BAM and NalMed-A produced rapid and smooth immobilization and recovery after reversal. All treatments in combination with manual restraint caused some degree of hyperthermia, hypoxemia, hypercarbia, bradycardia, respiratory and metabolic acidosis, and elevated lactate and serum cortisol. At 60 d, all deer were still alive, with no apparent residual effects. Vital signs of deer exposed to manual restraint and these drug combinations should be monitored closely, with supportive therapy provided when needed. We suggest BAM and NalMed-A are safe for immobilizing deer in situations similar to our trials, although doses may perform differently in deer remotely injected without manual restraint.
This study describes two different doses of dexmedetomidine combined with tiletamine-zolazepam (TZ) for anesthesia in snow leopards (Panthera uncia). A total of 11 adult snow leopards were anesthetized in Xining City, Qinghai Province, China from November 2019 to June 2023. We recorded the onset time, anesthesia duration, head-up time, and walking time. Vital signs were recorded every 5 min during anesthesia. Arterial blood gas analysis was performed approximately 20 min after the onset of anesthesia by collecting blood from the femoral artery. All results were presented as mean±SD. There were no significant differences in onset time, anesthesia duration, head-up time, and walking time between the two anesthesia protocols. Heart rate, respiratory rate, body temperature, and blood pressure had a gradual decreasing trend, and blood oxygen saturation gradually increased. Our results suggest that using dexmedetomidine at doses of 21.25±1.38 lg/kg to 30.95±1.13 lg/kg combined with TZ at 2.07±0.08 mg/kg to 2.13±0.15 mg/kg can provide safe and effective anesthesia for snow leopards.
Kayla G. Adcock, Alisia A. W. Weyna, Michael J. Yabsley, Rowan E. Bäck, Kayla Buck Garrett, Kevin D. Niedringhaus, Melanie R. Kunkel, Heather M. A. Fenton, M. Kevin Keel, Charlie S. Bahnson, Elizabeth Elsmo, Nicole M. Nemeth
The Wild Turkey (Meleagris gallopavo) is a geographically widespread, popular game bird and conservation icon in North America. Following successful reestablishment in parts of the US and Canada, regional declines have fueled population health concerns; therefore, understanding mortality causes and spatiotemporal patterns of disease is important to uncover potential ongoing and future health risks. Histomonosis, caused by the trichomonad Histomonas meleagridis, is a well-established and potentially fatal disease in Wild Turkeys; however, its prevalence and potential population health impacts remain poorly understood. Moreover, molecular tools recently have allowed for the detection of additional trichomonads that similarly can cause fatal disease in Wild Turkeys. We describe and compare disease due to H. meleagridis with that of Tetratrichomonas gallinarum, Tritrichomonas sp., and Simplicimonas sp. in Wild Turkeys in the southeastern US. Among 857 Wild Turkeys evaluated postmortem from 2002 to 2023, 34 (4.0%) were diagnosed with trichomonad disease, often assumed to be histomonosis prior to molecular testing. However, among 25 debilitating to fatal trichomonad disease cases for which etiologies were confirmed by PCR from 2015 to 2023, H. meleagridis was detected in 16/25 (64.0%), T. gallinarum in 6/25 (24.0%), Tritrichomonas sp. in 2/25 (8.0%) and Simplicimonas sp. in 1/25 (4.0%). These turkeys had similar clinical manifestations, and although lesion patterns varied to some extent, liver and/or intestinal tract was most commonly affected. Coinfections were common among all turkeys with trichomonad disease from 2015 to 2023 (21/25, 84.0%) and included viruses (lymphoproliferative disease virus, avian poxvirus), bacteria (Streptococcus gallolyticus, Listeria monocytogenes, Escherichia coli), and other protozoa (Sarcocystis sp., Haemoproteus sp.). Our results highlight the importance of molecular diagnostic testing in determining etiologies of trichomonad disease in Wild Turkeys. Further evaluation of the epidemiology and pathogenesis of trichomonad disease and its varied etiologies in Wild Turkeys and other birds is warranted to better understand risk factors and otential health im acts.
Through evaluation of serum and plasma buterylcholinesterase (BChE) and brain acetylcholinesterase (AChE) activity, we investigated the possibility of the involvement of an acute organophosphate toxicosis in the pathogenesis of ongoing annual outbreaks of paresis and paralysis that in some cases progress to death, in endangered Western Australian Carnaby's cockatoos (Zanda latirostris). The condition, named Carnaby's hindlimb paralysis syndrome (CHiPS), was first described in 2012. Following initial investigations involving clinical, epidemiologic, toxicologic, gross necropsy, and histologic evaluation, a toxic etiology, specifically an organophosphate toxicosis, was considered most likely. The study aimed to validate the BChE assay for use in serum and plasma in Carnaby's cockatoos. This study found no evidence of changes in serum or plasma BChE or brain AChE that indicate an acute organophosphate toxicosis as the cause of CHiPS. Although these results render an acute organophosphate toxicosis unlikely, an organophosphate-induced delayed neuropathy has not been ruled out. Based on the results from the BChE validation study, the authors can recommend this assay for the evaluation of BChE measurement in plasma and serum from Carnaby's cockatoos with results showing excellent accuracy and precision.
Rehabilitation and release of wild birds hinge upon a comprehensive understanding of both biologic and nonbiologic factors, including the medical and physical fitness of the animal. The objectives of this study were to determine reference intervals of packed cell volume and plasma chemistry values for healthy Eurasian Eagle Owls (Bubo bubo) and to compare blood values between age and sex classes. There were significant differences between males and females in total protein and globulin mean values, with males having higher values than females. Adult and juvenile Eagle Owls differed significantly in the mean values of calcium, alkaline phosphatase, and uric acid, with juveniles having higher values than adults. The calculated reference intervals for Eagle Owls can be used in Eurasian Eagle Owls admitted to rescue centers to assist veterinarians and wildlife managers to clinically evaluate and monitor the health of Eagle Owls and make decisions about when to release them after treatment.
Leptospirosis caused by the pathogenic serovars of Leptospira spp. is a zoonotic disease of global importance. Brown rats (Rattus norvegicus), due to their worldwide distribution and reservoir host status, are considered the most important reservoir for environmental leptospiral persistence and infections in animals. We aimed to isolate, identify, and characterize Leptospira spp. circulating among brown rat populations in Zaria, Kaduna state, Nigeria. Kidney samples from 305 brown rats from different locations in Zaria were collected April–June 2022 and cultured using bacteriologic methods. We also extracted DNA from 24 kidney tissue samples for molecular detection of pathogenic Leptospira spp. and for phylogenetic analysis. Leptospira spp. was detected in 57.7% of the samples by using culture methods and in 91.7% of the samples by using PCR. The phylogenetic tree revealed two distinct clusters among the reference sequences, aligning with the known P1 and P2 subclades. The sequences from this study all clustered together on the phylogenetic tree and were most similar to Leptospira interrogans serovar Pomona strain RZ 11. The high prevalence of Leptospira spp. detected in Zaria suggests that further surveillance and assessment of the public risk are warranted.
Klebsiella spp. are gram-negative facultative anaerobic heavily encapsulated bacteria associated with opportunistic and primary infections in a wide range of species. We assessed a series of cases (n=8) of necrosuppurative peritonitis, lymphadenitis, and/or pyelonephritis in wild juvenile raccoons (Procyon lotor) that died under rehabilitator care in New York, New Jersey, and Wisconsin, US, between July 2020 and December 2023, plus a retrospective case of a juvenile raccoon necropsied from New York in August 2011. Gross necropsy (n=9) and histopathology (n=9) were performed to characterize the lesions, whereas bacterial culture (n=8) was used to identify and characterize the bacteria and associated phenotype. We observed gram-negative short rods and coccobacilli (7/9; 78%), fibrinosuppurative peritonitis of variable severity (7/9; 78%) correlated to gross pyoabdomen (5/9; 56%) or abscessation (2/9; 22%), lymphadenomegaly and associated necrosuppurative lymphadenitis (5/9; 56%), and urinary tract disease (3/9; 33%). Aerobic culture of affected tissues isolated Klebsiella pneumoniae (n=4), K. pneumoniae subsp. ozaenae (n=2), Klebsiella variicola (n=1), and Klebsiella sp. (n=1). Our study strongly suggests an association of bacteria within the K. pneumoniae complex with peritonitis, lymphadenitis, and pyelonephritis in raccoons. Disease might be associated with underlying nosocomial infection given that all animals were under rehabilitator care at the time of death.
Brandon M. McDonald, Michael V. Cove, Mark G. Ruder, Michael J. Yabsley, Kayla B. Garrett, Alec T. Thompson, Nicole M. Nemeth, Jeremy D. Dixon, Marcus A. Lashley
We collected and screened black rats (Rattus rattus) in Key Largo, Florida, USA, to determine the potential role of disease or parasites in the collapse of the local population. Rats appeared healthy, but 94% (n=15/16) tested positive for Sarcocystis sp. The partial 18S rRNA gene sequence was 98.7–99.7% similar to a strain of Sarcocystis zuoi that is now considered a strain of the newly described Sarcocystis kani within the larger S. zuoi species complex that contains numerous new species. These Sarcocystis spp. use Asian snakes as definitive hosts and rodents, shrews, or tree shrews as intermediate hosts. Pythons are the definitive host for several Sarcocystis spp. in Asia, including a related parasite (Sarcocystis singaporensis) that has been used as a biologic control agent for Rattus spp. in southeast Asia. It is probable that increasing numbers of invasive Burmese pythons (Python bivittatus) in the Florida Keys are contributing to the spread of this parasite in addition to imposing predation pressure on both rodents and native snakes. As such, further surveillance and molecular and morphologic characterization of parasites from rodents and snakes in south Florida should be prioritized.
Wildlife may be infected with a high diversity of piroplasms and may serve as hosts or reservoirs for piroplasms of importance for domestic animals and public health. In the US, some piroplasms (e.g., Babesia spp. and Theileira cervi) have been associated with disease in native and exotic ungulates. Blood from 447 ruminants in Nevada were PCR tested for piroplasms, with 115 individuals from five species or subspecies found positive: 28/46 California bighorn sheep (Ovis canadensis californiana), 1/16 desert bighorn sheep (Ovis canadensis nelson), 70/255 mule deer (Odocoileus hemionus), 14/53 elk (Cervis canadensis nelsoni), and 2/55 pronghorn (Antilocapra americana). Six mountain goats (Oreamnos americanus) and four moose (Alces alces) were negative. Four piroplasm species were detected—Babesia duncani, Babesia sp. RD63, Babesia odocoilei, and Theileria cervi–like spp.—but three B. duncani strains were detected, giving seven unique species or strains. Babesia duncani, the most common piroplasm detected (83%), occurred in California and desert bighorn sheep, elk, and mule deer. Bighorn sheep were only infected with B. duncani, whereas mule deer and elk were each infected with three piroplasm species or strains. The single Theileria sp. and B. odocoilei detections were in pronghorn. Free-ranging ruminants in Nevada are infected with a high diversity of piroplasms, several of which are zoonotic or reported to cause disease in both wild and domestic ruminants.
Elly M. Blake, Kaylee A. Byers, Michael Joseph Lee, Jingxin Cao, Christine Layne, Jamie Borlang, Denise Huynh, Anton Andonov, Kevin S. Kuchinski, Jessie Lynch, Sarah J. Robinson, Anne-Marie Nicol, Chelsea G. Himsworth
Hepatitis E virus (HEV) is a globally distributed pathogen that causes acute hepatitis in people. Recent human cases of HEV arising after contact with urban rats (Rattus spp.) have raised concerns regarding whether rats may be a source of HEV infection. We investigated whether urban Norway rats (Rattus norvegicus) could be a source of HEV in an underserved urban neighborhood of Vancouver, Canada. We found that 15% of rats tested positive for rat HEV, and that HEV status was associated with increasing rat body length and family relationships. Rat HEV isolates were clustered according to their location on either the east or west side of a busy roadway bisecting this neighborhood, suggesting that this street is a barrier to HEV spread. Widespread distribution of HEV among rats in this neighborhood poses potential human health risks, emphasizing the need to reduce close contact of people with rats and their excreta.
Chronic wasting disease (CWD) is a fatal neurodegenerative disease of cervids caused by an infectious misfolded protein (prion). Several members of the Cervidae, including Rocky Mountain elk (Cervus canadensis nelsoni), are susceptible to CWD. There is no evidence of complete genetic resistance to CWD; the M132L polymorphism in the elk prion protein gene influences the incubation period: longest in 132LL, intermediate in 132ML, and shortest in 132MM elk. We retrospectively analyzed six female 132LL elk housed in an environment heavily contaminated with prions to 1) document clinical outcomes and incubation periods, 2) describe PrPSc distribution and extent in tissues, and 3) characterize their histologic lesions. In five of six elk, PrPSc was detected postmortem, with a distribution pattern distinct from that of 132MM and 132ML elk; time to clinical CWD onset CWD ranged from 73 to 117 mo (6.1–9.8 yr). Although the remaining animal was observed for 220 mo (18.3 yr), PrPSc was not detected in its tissues postmortem. This study suggests that 132LL elk infected via natural exposure may live even longer with CWD than previously thought, but ultimately remain susceptible. We also report a distinct distribution of PrPSc in 132LL genotypes and highlight unusual histologic findings. Understanding the relationship between cervid genetics and CWD is of increasing importance, especially given the growing interest in leveraging genetics that delay disease onset despite not preventing infection.
Toad flies in the genus Lucilia (previously referred to as Bufolucilia spp.) parasitize and cause myiasis in several amphibian species in North America. From 2019 to 2022, we documented Lucilia bufonivora infections in post-metamorphic western toads (Anaxyrus boreas) during amphibian surveys in four wetlands in Glacier National Park, Montana, US. We found nine infected adult toads in 2019, seven infected adults in 2020, one infected juvenile in 2021, and five infected adults plus one infected juvenile in 2022. We also captured Columbia spotted frogs (Rana luteiventris) during these same surveys but detected no infections. Only one of the four wetlands had infected toads in 2019, despite their proximity and hydrologic connectivity, but two of these wetlands had infections in 2020, and a third had a single infection in 2021. The same three of four wetlands had infections in 2022. In 2008, a similar parasitic infection in one western toad had been noted at the same wetland as in 2019. That toad had been captured again two years later without signs of infection.
Molecular approaches are becoming more prevalent for the diagnosis of neurodegenerative diseases in human medicine and can be extended to diagnosis of wildlife diseases such as chronic wasting disease and other prion diseases. These diseases have been associated with exosome-bound molecular biomarkers of disease progression, such as proteins and micro RNA molecules (miRNA). We tested and optimized a method for exosomal miRNA isolation from minimally invasive, small-volume serum samples obtained from white-tailed deer (Odocoileus virginianus). We confirmed the isolation of exosomes and optimized a commercially available benchtop kit to obtain sufficient and pure RNA for miRNA sequencing. The selected method for RNA extraction combines two 500-mL serum aliquots into one elution column and re-eluting the final product of the column. We identified 137 miRNA present in healthy white-tailed deer that can be used as a baseline to identify putative miRNA biomarkers of disease progression and mechanisms of infection in future comparative disease studies. This approach to biomarker discovery may help to inform biological processes in wildlife populations and provide alternatives to invasive or postmortem samples.
We estimated the probabilities of detecting one or more chronic wasting disease (CWD) cases (Pdet) in free-ranging cervids in the continental US during 1997 - 2001. Based on sample sizes reported by respective state authorities at the time and a target for detectable apparent prevalence (i.e., a design prevalence) of 0.001 (one positive per 1,000 animals statewide), estimated Pdet were <50% for 39/46 states where CWD had not been detected in the wild prior to 1997 and were <5% in 20/26 states located east of the Mississippi River. The survey designs and sample sizes reported by most states prior to 2002 would have yielded exceedingly small detection probabilities for focal CWD outbreaks. Although most CWD foci in the US were first detected in 2002 or after, the data presented here and elsewhere suggest it is plausible that an unknown number of these—some established perhaps decades earlier—were already present but had simply eluded detection. These data highlight uncertainty regarding timelines for CWD emergence in the US. Accepting—and to the extent possible quantifying—uncertainty in the historical distribution of CWD throughout the US seems a necessary foundation for better understanding its emergence, its drivers and patterns of spread, and its response to various interventions—past, present, and future.
We investigated the prevalence of arthropod-borne viral diseases in a population of free-ranging mantled howler monkeys (Alouatta palliata) in Costa Rica in 1998. Blood samples were opportunistically collected from monkeys anesthetized for another study. Serology was performed on 64 individuals to assess exposure of this population to vesicular stomatitis virus, equine encephalitis viruses, Mayaro virus, St. Louis encephalitis virus, yellow fever virus, and dengue virus. The New Jersey serotype of vesicular stomatitis (VSV-NJ) was the only pathogen for which the population tested positive (44% [28/64]). This is the first report of antibodies against VSV-NJ in nonhuman primates in Costa Rica.
Baylisascaris procyonis is a roundworm that does not affect its definitive host, raccoons (Procyon lotor), but may have a devastating effect when ingested by paratenic hosts such as Allegheny woodrats (Neotoma magister). Despite being considered a major factor in woodrat population extirpation and decline in states northward, there have been no large-scale surveys for raccoon roundworm in Virginia, US. From 2022 to 2024, we visited 60 karst or nonkarst rocky habitats known (current or historical) or suspected to be Allegheny woodrat locations in western Virginia. We opportunistically collected raccoon feces as individual piles or subsampled from visible latrines. We used fecal flotation to determine the presence and prevalence of raccoon roundworm eggs in samples collected from 44 sites across 15 counties and 1 independent city. We found evidence of this roundworm at eight (18.2%) sites in six counties. Because woodrats are especially vulnerable to fatal larval infections with B. procyonis, the presence of the parasite at multiple sites suggests conservation measures should be implemented to protect these populations.
Emydomyces testavorans is an onygenalean fungus associated with shell and skin lesions in chelonians and is increasingly linked to morbidity and mortality. Effective disinfection methods are a critical component of biosecurity protocols to prevent and manage emydomycosis; however, disinfectant efficacy against E. testavorans is unknown. This study determined the in vitro efficacy of 13 disinfectants across a range of concentrations and exposure times used in veterinary, wildlife, and environmental settings against E. testavorans. Pure E. testavorans culture material was exposed to each disinfectant at manufacturer-recommended concentration and exposure times in triplicate. Disinfectant was removed via centrifugation and cultures were inoculated onto inhibitory media plates, maintained at room temperature (20–22 C), and examined weekly for fungal growth. After 6 wk of incubation, ethanol, Virkon S (active ingredient potassium peroxymonosulfate 21.41%), benzalkonium chloride, and desiccation proved ineffective at completely inhibiting fungal growth. All other agents, including bleach, chlorhexidine, and accelerated hydrogen peroxides, effectively inhibited fungal growth. These data suggest that several effective disinfection options are available for use against E. testavorans. These findings can be used in managed care and field settings to reduce transmission of E. testavorans between turtles through contaminated surfaces and equipment.
Ectoparasite loads of birds may be governed, in part, by the climatic characteristics of their environment. We surveyed live-trapped American Kestrels (Falco sparverius caribaearum) for lice and other ectoparasites on the humid subtropical island of Puerto Rico during March–May 2024. The main goal was to compare the prevalence and abundance of lice on kestrels in Puerto Rico to recently published data on the lice of kestrels 1000 km away in the Bahamas, and to the lice of kestrels in an arid region of the western US (Utah). A brief general inspection of the plumage of 39 captured birds was followed by careful examination of the underside of wing primary feathers under a dissecting microscope. Two species of lice were collected, Colpocephalum subzerafae and Degeeriella carruthi, neither previously recorded from kestrels in Puerto Rico. The same two species are present on kestrels in the Bahamas. The prevalence and abundance of lice on kestrels in Puerto Rico and the Bahamas were similar, while being much greater than the prevalence and abundance of lice on kestrels in arid Utah, US. We also collected two species of hippoboscid flies (Diptera: Hippoboscidae): Microlynchia pusilla, not previously recorded on the American Kestrel, and Ornithoctona erythrocephala. These flies, as well as the lice, might affect the health of kestrels both directly, e.g., causing anemia by feeding on blood, and indirectly by vectoring endoparasites.
Effects on physiology were evaluated in 49 free-ranging moose (Alces alces), 11 adult males, 36 females, two of unknown sex) in Minnesota, USA, immobilized by helicopter darting with thiafentanil (10 mg) and xylazine (30 mg) in February 2020 and March 2021. Pursuit time (PT), induction time (IT), recumbency time (RT), recovery time (RC), temperature (T), and body position were recorded. For 14 females, respiratory rate (RR), pulse rate (PR), and pulse oximetry (SpO2) were obtained before and at 1, 5, and 10 min after 4 L/min nasal oxygen supplementation was started; pH, lactate (Lac), arterial oxygen (PaO2), and carbon dioxide (PaCO2) tensions were obtained pre-treatment and 5 min post-treatment. Immobilizations were reversed with naltrexone (200 mg) and tolazoline (800 mg) intramuscularly. Median PT and IT were 4 min; a longer dart needle significantly reduced IT (P=0.0274). Most (98%) remained sternal; 77% held their head upright. Median RC was 3 min. Temperature remained ≤41.2 C. Median RR, PR, and SpO2 were RR=20 breaths/min, PR=70 beats/min, SpO2=91% pre-treatment and RR=30 breaths/min, PR=72 beats/min, SpO2=97% 5-min post-treatment. Median blood gas values were pH=7.45, Lac=5.62 mmol/L, PaCO2=44 mmHg, and PaO2=65 mmHg pre-treatment and pH=7.48, Lac=4.99 mmol/L, PaCO2=41.1 mmHg, and PaO2=78 mmHg 5-min post-treatment. Physiologic improvement from oxygen supplementation was clinically relevant but not statistically significant. All moose survived immobilization. Thiafentanil and xylazine combination provided safe and effective immobilization in free-ranging moose.
Anna Didkowska, Víctor Martín-Santander, Marlena Wojciechowska, Wanda Olech, Krzysztof Anusz, Antonio Fernández, Janine E. Davies, Marta Ruíz de Arcaute, Delia Lacasta, Sergio Villanueva-Saz, Diana Marteles
The European Bison (Bison bonasus) is the largest mammal in Europe and is classified as an endangered species. Leishmaniosis is a vector-borne disease caused by the protozoan Leishmania infantum. In general, this infection has been associated with dogs, cats, and humans. However, epidemiologic studies and reports confirm that the parasite is able to infect many other mammalian species. Recent evidence has demonstrated that ruminants in endemic areas are exposed to L. infantum infection. Moreover, climate change has allowed the northward spread of vector species, causing the expansion of L. infantum infection in regions traditionally classified as nonendemic in Europe. The aim of this study was to determine the presence or absence of anti–L. infantum antibodies in serum samples from 343 European bison in Poland, collected from 2017 to 2023. For this purpose, the presence of anti-Leishmania antibodies was analyzed using an in-house multispecies ELISA. Anti-Leishmania antibodies were detected in four animals, an overall seroprevalence of 1.17%. The results provide scientific evidence of serologic exposure to the parasite in Poland, a country previously considered nonendemic for L. infantum infection.
Kathleen Apakupakul, Ainoa Nieto-Claudin, Tsanta F. Rakotonanahary, Lilian S. Catenacci, Fidisoa Rasambainarivo, Santatriniaina Randrianarisoa, Carlos Sacristán, Encarnación Madueño, Bonnie L. Raphael, Sharon L. Deem
Mycoplasmosis is of concern for chelonian conservation. We detected a Mycoplasma sp. in confiscated radiated tortoises (Astrochelys radiata) and spider tortoises (Pyxis arachnoides). Sequence analysis of the 16S-23S ribosomal RNA intergenic spacer region was consistent with Mycoplasma agassizii. Mycoplasma spp. have not been previously reported in native tortoises in Madagascar.
Transmissible spongiform encephalopathy, or prion disease, poses a serious threat to wildlife; however, the susceptibility of apex predators is still being assessed. We investigated variation in the prion protein gene in Florida panthers (Puma concolor coryi) and found that admixture from Central American pumas probably introduced a novel, albeit benign, prion allele.
To examine whether Ostertagia mossi and Ostertagia dikmansi from white-tailed deer (Odocoileus virginianus) are separate species, we obtained DNA sequences for the cytochrome C oxidase subunit I and internal transcribed spacer 2 gene targets for phylogenetic analyses. Neither target revealed separation between morphotypes, confirming they are the same species and providing new data on Ostertagia morphotypes.
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