Journal of Wildlife Diseases最新文献

The collection and storage of swab samples for molecular diagnostics is a routine component of wildlife health surveillance. The suitability of different sample storage conditions for maximizing the recovery of pathogen DNA in most species has not been assessed; therefore, the aim of this study was to identify a preferred storage method for swabs collected for the detection of frog virus 3 (FV3), a significant chelonian pathogen. Sterile swabs were inoculated in triplicate with a plasmid containing known quantities of FV3 DNA from 100 to 107 copies. Swabs were then stored under one of the following four conditions: 1) dry frozen at -20 °C; 2) immersed in phosphate-buffered saline (PBS) and frozen at -20 °C; 3) immersed in a nucleic acid preservative (RNAlater) and frozen at -20 °C; and 4) immersed in 100% ethanol at ambient room temperature. Swabs remained undisturbed under designated storage conditions for 14 d, at which point DNA extraction and conventional and quantitative PCR for FV3 detection were performed. Conventional PCR amplified down to the lowest expected FV3 target copy number (10,000 copies/swab) for the dry-frozen and PBS-frozen treatment groups. Conventional PCR amplification was inconsistent for the ethanol and RNAlater treatment groups. Quantitative PCR on dry-frozen samples successfully amplified as low as 100 FV3 target copies/swab with a mean recovery of 90%, with all other storage methods amplifying only down to 10,000 copies/swab. Findings suggest there is improved detection of pathogen DNA for samples stored from collection to extraction under the dry-frozen method. Swab sample storage recommendations for future applications should be observed within the context of study-specific objectives and target pathogens. Furthermore, failure to detect fewer than 100 copies/swab of FV3 from any storage method may have clinically significant ramifications and suggests that the differences in DNA recovery based on extraction method should also be examined.

This study detected Trichomonas gypaetinii in Black-tailed Gulls (Larus crassirostris) in South Korea. We collected 83 samples (80 oropharyngeal swabs from live birds and three carcass-derived specimens) from breeding colonies on Nando and Hongdo islands and coastal habitats in Taean, South Korea, in 2023-24. Molecular analysis using nested PCR targeting the ITS region revealed an exceptionally high prevalence (98.8%) of Trichomonas spp., with both Trichomonas gallinae and Trichomonas gypaetinii identified. We observed significant seasonal variation in Trichomonas spp. distribution, with T. gallinae predominating in winter (85%), while T. gypaetinii became more prevalent during breeding and migration periods (67%). Co-infections were documented at both breeding colonies, suggesting potential interspecies interactions. Sex-based differences in infection patterns were statistically significant (P<0.05); T. gypaetinii showed higher prevalence in adult males at Nando Island (88%) and in adult females at Hongdo Island (88%). Despite the high infection rate, no distinctive lesions were observed in examined carcasses, raising questions about pathogenicity and host adaptation. These findings expand the known host range of this protozoan parasite beyond raptors. This, together with previous detection of T. gallinae in other seabird species (Streaked Shearwater [Calonectris leucomelas] and Swinhoe's Petrel [Hydrobates monorhis]), highlights the need for expanded surveillance of Trichomonas spp. in nonraptor species and further investigation into transmission dynamics, pathogenicity, and potential impacts on reproductive success and population health in colonial nesting birds.

The decline in koala (Phascolarctos cinereus) populations has been significantly driven by infectious diseases, with chlamydial disease contributing to this trend. Chlamydia pecorum is often codetected with viruses such as phascolarctid gammaherpesvirus 1 and 2 (PhaHV-1 and PhaHV-2). Koalas can also be infected with other bacteria, including Bordetella bronchiseptica, which causes sporadic respiratory disease outbreaks. Respiratory infections and respiratory disease in koalas remain under-investigated. This study reports the detection of C. pecorum, Chlamydia pneumoniae, Chlamydia psittaci, B. bronchiseptica, PhaHV-1, and PhaHV-2 in 102 samples from 49 koalas that presented to veterinary facilities in South East Queensland, Australia from 2018 to 2023. The koalas included seemingly healthy individuals (n=21), koalas with respiratory disease (n=18), and koalas with other diseases (n=10). Overall, C. pecorum was detected in 37% of koalas, C. pneumoniae in 2%, C. psittaci in 0%, B. bronchiseptica in 18%, PhaHV-1 in 41%, and PhaHV-2 in 6%. Coinfections with three agents were common, particularly in koalas with signs of disease. Among the 18 koalas with respiratory disease, one was coinfected with four agents (B. bronchiseptica, C. pecorum, PhaHV-1, and PhaHV-2), and four were coinfected with three agents (B. bronchiseptica, C. pecorum, and PhaHV-1). Additionally, six koalas had coinfections involving two agents: two with C. pecorum and PhaHV-1, two with B. bronchiseptica and PhaHV-1, one with B. bronchiseptica and C. pecorum, and one with PhaHV-1 and PhaHV-2. Analysis of the genetic diversity of infecting chlamydial strains detected in koalas with respiratory and other diseases, based on the full-length ompA gene, identified previously characterized C. pecorum and C. pneumoniae ompA genotypes, as well as a unique C. pecorum ompA genotype. This study highlights the need for incorporating these infectious agents into koala respiratory diagnostics and emphasizes the need for continued research to investigate the complexities of these infections.

Abstract: Mycoplasma bovis is a growing threat to American bison (Bison bison) health and restoration efforts, causing significant mortality and disease in affected bison herds. Despite this, little is known about the epidemiology or clinical course of M. bovis infection in bison. In this study, we present continued observations from a cohort of naturally infected American bison, in which maintenance of subclinical M. bovis infections was previously reported. Most (8 of 11) surviving previously infected animals mounted a detectable immunoglobulin G (IgG) response that waned within 6-24 mo. Two bison mounted and maintained robust IgG antibody responses throughout the study period; one of these also remained quantitative PCR and culture positive throughout the study. One animal failed to mount a detectable IgG response despite becoming infected with M. bovis during the study. Also, naïve animals (n=4) were added to the environment where positive animals were previously kept, shared a water tank with known positive animals, and were finally added to the cohort and sampled at 3-mo intervals for a 2-yr follow-up period. The four naïve animals, and a calf born to one of them, remained M. bovis negative despite commingling with known positive animals in the cohort. We discuss limitations of current antemortem test approaches and the need for more accurate testing to support healthy bison restoration and management.

This study provides the first record of helminth prevalence associated with Magellanic penguins (Spheniscus magellanicus) at the southernmost limit of their distribution, in the Beagle Channel, Argentina. Using a noninvasive and indirect nest soil sampling approach, we detected multiple helminth morphotypes, including nematodes, cestodes, trematodes, and acanthocephalans. Nematodes were the most frequently encountered group. Helminth load was greater during chick rearing than in the postbreeding period, likely due to increased fecal deposition and favorable environmental conditions. Parasite occurrence also varied across colony erosion zones shaped by penguin activity and natural processes, suggesting that microhabitat characteristics influence helminth persistence. These findings underscore the utility of soil sampling for monitoring temporal patterns of parasite exposure, particularly in remote wildlife populations, highlighting the need for continued surveillance of penguin health. Future research integrating direct parasitological and molecular techniques will improve taxonomic resolution and advance the understanding of parasite transmission dynamics.

Eurasian beavers (Castor fiber) were reintroduced to Scotland, UK, after more than two centuries of extinction. Giardia spp. are important protozoal parasites causing waterborne gastroenteritis in humans, with the zoonosis known as "beaver fever" in North America, raising public health concerns in Scotland. Using a rapid enzyme immunochromatographic assay (SNAP Giardia, IDEXX Laboratories, Inc) for soluble Giardia antigen, we tested 274 live wild beavers trapped for translocation (2019-25) and 26 wild beavers found dead. Prevalence was 1.83% (n=5/274) in live beavers (95% confidence interval, 0.6-4.21), with no clinical illness observed. Beavers that were positive for Giardia antigen on testing were treated and retested as negative before translocation. Prevalence was highest in kits at 3.7% (n=3/81) and lowest in adults at 0.71% (n=1/140), but the difference did not reach statistical significance. One dead adult female tested positive, with no evidence of disease and death was attributed to sepsis from bite wounds. Wild Eurasian beavers in Scotland currently do not appear to pose a notable Giardia infection risk to humans or animals, especially compared with the higher prevalence in local domestic animals.

Necropsy and histopathology of a juvenile bobcat (Lynx rufus) revealed neuronal necrosis with nuclear inclusion bodies and vacuolation and immunolabeling with parvovirus immunohistochemistry. Infection with canine parvovirus was confirmed by PCR. This brain lesion is an uncommon manifestation of parvovirus in non-neonatal animals and is particularly rare in wild felids.

At their southern range limits in North America, moose (Alces alces) experience increased overlap with white-tailed deer (Odocoileus virginianus) and associated parasites through shared habitat use. Moose persist at low densities in New York state, USA, and are incidental hosts to multiple pathogenic endoparasites. Understanding the contributions of endoparasitism to moose morbidity and mortality requires investigation into their health status and drivers of parasite infection. We summarized health data from 60 live-captured and 191 opportunistically necropsied moose (spanning 2000-23) and used generalized linear modeling to assess the determinants of moose infection by giant liver fluke (Fascioloides magna) and meningeal worm (Parelaphostrongylus tenuis). Despite 98% of live moose having good or excellent body condition, 75% were potentially infected with at least one internal parasite species. Hematologic analyses of live moose indicated elevated eosinophil and lymphocyte counts. Infestations with winter tick (Dermacentor albipictus) were common on live-captured New York moose (74%), although intensities were considerably lower than on moose in neighboring states. Necropsied moose were commonly infected with F. magna and P. tenuis, but most often succumbed to trauma from vehicle collisions. Density of white-tailed deer, definitive host to both endoparasites, was the primary driver of P. tenuis infection in moose. For F. magna, moose age and sampling year were positively associated, whereas deer density and road density were negatively associated with moose infection probability. Limiting deer densities in core moose areas may help reduce the risk of P. tenuis infection, and targeted management efforts could promote resilience of small moose populations to multiple parasites.

Abstract: Besnoitia tarandi is a protozoan commonly reported in reindeer and caribou (Rangifer tarandus spp.), in which it can be associated with morbidity and even mortality. Anecdotal observations suggest that the prevalence and intensity of this parasitic infection vary between caribou herds, but the lack of a standardized method to evaluate the intensity of infection limits inter-herd comparisons. The presence and intensity of Besnoitia sp. infection in metatarsal skin were evaluated using a standardized histopathologic technique in 1,361 migratory caribou sampled from eight herds across Canada, Alaska (USA), and Greenland. Besnoitia sp. was not detected in the two Greenlandic herds but was observed in animals from the six other herds sampled, with prevalence ranging from 4.2-63.9% for subsets of caribou by season and/or sex, and cyst density ranging from 0.08-13.14 cysts/mm2 among herds. Observed prevalence of infection was highest in the two Canadian Québec-Labrador herds (Rivière-George and Rivière-aux-Feuilles) and lowest in the Canadian Southampton Island herd. This study provides new insights into the epidemiology of besnoitiosis in migratory caribou populations in North America.

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.