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Effective, long-term strategies to manage the threat of bovine tuberculosis and brucellosis spillback from northern, diseased bison to the Canadian cattle herd and adjacent disease-free wood bison (Bison bison athabascae) herds have eluded policy makers in recent decades. A controversial plan to depopulate infected herds and repopulate them with disease-free wood bison was rejected in 1990 because of significant public concern. Since then, technical advances in vaccine technology, genetic salvage, selective culling, and diagnostic test development have occurred. Containment strategies to reduce further spread of these diseases are a necessary first step; recent progress has been made in this area, but challenges remain. This progress has produced more options for management of these herds in northern Canada, and it is time to consider wood bison conservation and long-term disease eradication as equally important goals that must satisfy concerns of conservation groups, agriculture sectors, aboriginal groups, and the general public. Management of wildlife disease reservoirs in other areas, including Yellowstone and Riding Mountain national parks, has demonstrated that effective disease management is possible. Although combinations of different strategies, including vaccination, genetic salvage techniques, and selective culling, that use sensitive and specific diagnostic tests may offer alternatives to depopulation/repopulation, they also have logistic constraints and cost implications that will need consideration in a multistakeholder, collaborative-management framework. We feel the time is right for this discussion, so a long-term solution to this problem can be applied.
Greater interaction between humans and wildlife populations poses significant risks of anthropogenic impact to natural ecosystems, especially in the marine environment. Understanding the spread of microorganisms at the marine interface is therefore important if we are to mitigate adverse effects on marine wildlife. We investigated the establishment of Escherichia coli in the endangered Australian sea lion (Neophoca cinerea) by comparing fecal isolation from wild and captive sea lion populations. Fecal samples were collected from wild colonies March 2009–September 2010 and from captive individuals March 2011–May 2013. Using molecular screening, we assigned a phylotype to E. coli isolates and determined the presence of integrons, mobile genetic elements that capture gene cassettes conferring resistance to antimicrobial agents common in fecal coliforms. Group B2 was the most abundant phylotype in all E. coli isolates (n = 37), with groups A, B1, and D also identified. Integrons were not observed in E. coli (n = 21) isolated from wild sea lions, but were identified in E. coli from captive animals (n = 16), from which class I integrases were detected in eight isolates. Sequencing of gene cassette arrays identified genes conferring resistance to streptomycin-spectinomycin (aadA1) and trimethoprim (dfrA17, dfrB4). Class II integrases were not detected in the E. coli isolates. The frequent detection in captive sea lions of E. coli with resistance genes commonly identified in human clinical cases suggests that conditions experienced in captivity may contribute to establishment. Identification of antibiotic resistance in the microbiota of Australian sea lions provides crucial information for disease management. Our data will inform conservation management strategies and provide a mechanism to monitor microorganism dissemination to sensitive pinniped populations.
Francisellatularensis is a highly virulent, zoonotic bacterium that causes significant natural disease and is of concern as an organism for bioterrorism. Serologic testing of wildlife is frequently used to monitor spatial patterns of infection and to quantify exposure. Cottontail rabbits (Sylvilagus spp.) are a natural reservoir for F. tularensis in the US, although very little work has been done experimentally to determine how these animals respond to infection; thus, information gathered from field samples can be difficult to interpret. We characterized clinical disease, bacteremia, pathology, and antibody kinetics of North American cottontail rabbits experimentally infected with five strains of F. tularensis. Rabbits were infected with four field strains, including MA00-2987 (type A1b), WY96-3418 (type A2), KY99-3387, and OR96-0246 (type B), and with SchuS4 (type A1a), a widely used, virulent laboratory strain. Infection with the different strains of the bacterium resulted in varied patterns of clinical disease, gross pathology, and histopathology. Each of the type A strains were highly virulent, with rabbits succumbing to infection 3–13 d after infection. At necropsy, numerous microabscesses were observed in the livers and spleens of most rabbits, associated with high bacterial organ burdens. In contrast, most rabbits infected with type B strains developed mild fever and became lethargic, but the disease was infrequently lethal. Those rabbits infected with type B strains that survived past 14 d developed a robust humoral immune response, and F. tularensis was not isolated from liver, spleen, or lung of those animals. Understanding F. tularensis infection in a natural reservoir species can guide serosurveillance and generate new insights into environmental maintenance of this pathogen.
West Nile virus (WNV) is an arbovirus transmitted enzootically by Culex mosquitoes among avian hosts. Since 2000, the California Dead Bird Surveillance Program (DBSP) has tracked avian mortality reported by the public on a telephone hotline and website and measured the prevalence of WNV infection in dead birds. We summarize herein WNV prevalence in dead birds tested and variation of WNV transmission over time and space with the use of DBSP data from 2003 to 2012. Prevalence among dead birds was highest in 2004, 2008, and 2012. This pattern was similar to peak WNV infection years for mosquitoes but not to human WNV incidence. Although American Crows (Corvus brachyrhynchos) were most frequently reported and tested, this species ranked third in infection prevalence (44%) after Yellow-billed Magpies (Pica nuttalli; 62%) and Western Scrub-Jays (Aphelocoma californica; 48%). Overall prevalence in American Robin (Turdus migratorius), House Finch (Haemorhous mexicanus), and House Sparrow (Passer domesticus) carcasses ranged from 18% to 22%. Corvid WNV prevalence was highest in South Coast, Bay/Delta, Sacramento, and San Joaquin valleys, and Klamath/North Coast bioregions, overlapping areas of elevated WNV activity in other surveillance measurements. Bioregional analysis revealed the avian species most likely to be reported and found positive in each bioregion. Our results may be useful to WNV surveillance and control efforts and provide insight into bird population trends in California.
Although rat feces are widely suspected to be a source of pathogenic bacteria, few investigators have studied fecal pathogens in rats. We investigated the prevalence and characteristics of Escherichia coli and Salmonella spp. in Norway and black rats (Rattus norvegicus and Rattus rattus, respectively) from an urban neighborhood of Vancouver, Canada, collected September 2011–August 2012. Colon content was cultured for E. coli and Salmonella spp. and screened for the seven most-common enteropathogenic Shiga toxin–producing E. coli (STEC) serotypes by PCR. Isolates were tested for antimicrobial resistance and Salmonella isolates were serotyped. We detected E. coli in 397/633 (62.7%) urban rats. Forty-one of 397 (6.5%) E. coli isolates were resistant to ≥1 antimicrobial while 17 (4.3%) were multidrug resistant (including two isolates demonstrating extended-spectrum β-lactamase resistance). Ten of 633 (1.6%) urban rats were carrying STEC serotypes including O145, O103, O26, and O45. Norway rats were more likely to be carrying E. coli compared to black rats, and there was geographic clustering of specific resistance patterns and STEC serotypes. Salmonella spp. were detected in 3/633 (0.5%) rats including serotypes Derby, Indiana, and Enteritidis. In contrast to zoonotic pathogens for which rats are the natural reservoir (e.g., Leptospira interrogans, Rickettsia typhi, Seoul virus), rats likely acquired E. coli and Salmonella spp. from their environment. The ability of rats to be a ‘sponge’ for environmental pathogens has received little consideration, and the ecology and public health significance of these organisms in rats requires further investigation.
Eileen M. McKee, Edward D. Walker, Tavis K. Anderson, Uriel D. Kitron, Jeffrey D. Brawn, Bethany L. Krebs, Christina Newman, Marilyn O. Ruiz, Rebecca S. Levine, Mary E. Carrington, Robert G. McLean, Tony L. Goldberg, Gabriel L. Hamer
Antibody duration, following a humoral immune response to West Nile virus (WNV) infection, is poorly understood in free-ranging avian hosts. Quantifying antibody decay rate is important for interpreting serologic results and for understanding the potential for birds to serorevert and become susceptible again. We sampled free-ranging birds in Chicago, Illinois, US, from 2005 to 2011 and Atlanta, Georgia, US, from 2010 to 2012 to examine the dynamics of antibody decay following natural WNV infection. Using serial dilutions in a blocking enzyme-linked immunosorbent assay, we quantified WNV antibody titer in repeated blood samples from individual birds over time. We quantified a rate of antibody decay for 23 Northern Cardinals (Cardinalis cardinalis) of 0.198 natural log units per month and 24 individuals of other bird species of 0.178 natural log units per month. Our results suggest that juveniles had a higher rate of antibody decay than adults, which is consistent with nonlinear antibody decay at different times postexposure. Overall, most birds had undetectable titers 2 yr postexposure. Nonuniform WNV antibody decay rates in free-ranging birds underscore the need for cautious interpretation of avian serology results in the context of arbovirus surveillance and epidemiology.
Intracranial abscess disease is a cause of natural mortality for mature male white-tailed deer (Odocoileus virginianus). Most cases of abscesses are associated with bacterial infection by Trueperella (Arcanobacterium) pyogenes, but a complete understanding of the epidemiology of this disease is lacking. We quantified the effects of individual characteristics, site-specific herd demographics, land cover, and soil variables in estimating the probability of this disease. We examined 7,545 white-tailed deer from 60 sites throughout Georgia US for signs of cranial abscesses, the predecessor of intracranial abscesses, and recorded the presence or absence of cranial abscesses for each individual examined. We detected no cranial abscesses in 2,562 female deer but 91 abscesses in 4,983 male deer examined (1.8%). A generalized linear mixed model, treating site as a random effect, was used to examine several potential explanatory risk factors including site-level landscape and soil characteristics (soil and forest type), demographic factors (deer density and male to female ratio), and individual host factors (deer sex and age). Model results indicated that the probability of a male having a cranial abscess increased with age and that adult sex ratio (male:female) was positively associated with this disease. Site-specific variables for land cover and soil types were not strongly associated with observations of the disease at the scale measured and a large amount of among-site variability remained. Given the demonstrated effect of age, gender, and local sex ratios but the remaining unexplained spatial variability, additional investigation into spatiotemporal variation of the presumed bacterial causative agent of cranial abscesses appears warranted.
We estimated the sensitivity and specificity of the caudal-fold skin test (CFT), the fluorescent polarization assay (FPA), and the rapid lateral-flow test (RT) for the detection of Mycobacterium bovis in free-ranging wild wood bison (Bison bison athabascae), in the absence of a gold standard, by using Bayesian analysis, and then used those estimates to forecast the performance of a pairwise combination of tests in parallel. In 1998–99, 212 wood bison from Wood Buffalo National Park (Canada) were tested for M. bovis infection using CFT and two serologic tests (FPA and RT). The sensitivity and specificity of each test were estimated using a three-test, one-population, Bayesian model allowing for conditional dependence between FPA and RT. The sensitivity and specificity of the combination of CFT and each serologic test in parallel were calculated assuming conditional independence. The test performance estimates were influenced by the prior values chosen. However, the rank of tests and combinations of tests based on those estimates remained constant. The CFT was the most sensitive test and the FPA was the least sensitive, whereas RT was the most specific test and CFT was the least specific. In conclusion, given the fact that gold standards for the detection of M. bovis are imperfect and difficult to obtain in the field, Bayesian analysis holds promise as a tool to rank tests and combinations of tests based on their performance. Combining a skin test with an animal-side serologic test, such as RT, increases sensitivity in the detection of M. bovis and is a good approach to enhance disease eradication or control in wild bison.
To determine the antimicrobial susceptibility profiles and prevalence of resistance genes in Escherichia coli isolated from yaks (Bos grunniens) and herdsmen in nine plateau pastures in Tibet, we isolated 184 nonidentical strains of E. coli from yaks and herdsmen. Antimicrobial susceptibility testing of 15 antimicrobials was conducted and the prevalence of sulfonamide resistance genes (sul1, sul2, and sul3) and florfenicol resistance genes (floR, cfr, cmlA, fexA, pexA, and estDL136) was determined. Escherichia coli isolated from yaks had a high resistance rate to sulfamethoxazole (44%), sulphafurazole (40.4%), and florfenicol (11.4%). Escherichia coli isolated from herdsmen had a high resistance rate to sulfamethoxazole (57%) and sulphafurazole (51%). In addition, sul genes were present in 93% of sulfonamide-resistant isolates (84/90), and 17 floR genes and four cmlA genes were found in 19 florfenicol-resistant isolates. Even though florfenicol is prohibited from use in humans, three floR genes were detected in strains isolated from herdsmen. The three floR-positive isolates from herdsmen had pulsed-field gel electrophoresis patterns similar to isolates from yaks. In addition to documenting the sul and floR genes in E. coli isolated from yaks and herdsmen in the Tibetan pasture, we demonstrated the potential risk that antimicrobial-resistant E. coli could spread among herdsmen and yaks.
Aeromonas hydrophila is a gram-negative, rod-shaped, facultative, anaerobic bacterium that is ubiquitous in freshwater and slightly brackish aquatic environments and infects fish, humans, reptiles, and birds. Recent severe outbreaks of disease in commercial channel catfish (Ictalurus punctatus) aquaculture ponds have been associated with a highly virulent A. hydrophila strain (VAH), which is genetically distinct from less-virulent strains. The epidemiology of this disease has not been determined. Given that A. hydrophila infects birds, we hypothesized that fish-eating birds may serve as a reservoir for VAH and spread the pathogen by flying to uninfected ponds. Great Egrets (Ardea alba) were used in this transmission model because these wading birds frequently prey on farmed catfish. Great Egrets that were fed VAH-infected catfish shed VAH in feces demonstrating their potential to spread VAH.
Timothy J. Smyser, Shylo R. Johnson, Melissa D. Stallard, Ashley K. McGrew, L. Kristen Page, Nikki Crider, Lora R. Ballweber, Robert K. Swihart, Kurt C. VerCauteren
Baylisascaris procyonis is a common gastrointestinal parasite of raccoons (Procyon lotor) and is a zoonotic helminth with the potential to cause severe or fatal infection. Raccoons thrive in human-dominated landscapes, and the fecal-oral transmission pathway and lack of effective treatment make B. procyonis a serious threat to public health. The distribution of medicinal baits has emerged as a socially acceptable and cost-effective method for managing disease in free-ranging wildlife. We assessed the suitability of a mass-producible anthelmintic bait for B. procyonis mitigation by evaluating the willingness of free-ranging raccoons to consume anthelmintic baits and determining whether bait consumption successfully cleared B. procyonis infections from raccoons. Anthelmintic baits were modified from standard fishmeal polymer baits, the food attractant commonly used in oral rabies vaccine baits, with the introduction of 220 mg of pyrantel pamoate into the fishmeal mixture. We captured 16 naturally infected raccoons, presented one anthelmintic bait, and monitored B. procyonis infection over 90 d by screening feces for eggs. Treatment cleared B. procyonis infections for nine of 12 raccoons that consumed >10 g of the 15 g bait. We used remote cameras to monitor in situ patterns of bait consumption for anthelmintic baits relative to standard baits. Both anthelmintic and standard baits were rapidly consumed, with no differences in the rate of consumption between bait types. However, after bait contact, raccoons demonstrated a greater willingness to consume standard baits while ignoring anthelmintic baits more frequently (P = 0.06). Initial trials of anthelmintic baits show promise, although refinement in both dose and palatability is needed. At mass production scales, the addition of pyrantel pamoate to fishmeal polymer baits would be inexpensive, potentially making anthelmintic baits a viable management option when coupled with an oral rabies vaccine or used independently for B. procyonis mitigation.
During a study on health and disease in Red-crowned Parakeets (Cyanoramphus novaezelandiae) on Tiritiri Matangi Island and Little Barrier Island (Hauturu-o-Toi) in New Zealand between 2011 and 2013, an outbreak of feather loss prompted the collection of skin biopsies (n = 135) under anesthesia from the head of captured birds. A subset of samples (n = 7) was frozen to obtain whole specimens for identification of ectoparasites. Mites (range 1–11) were observed in 79/135 (58.5%) skin biopsies, whereas feather loss was only found in 47/142 (33.1%) birds captured during the sampling period. Compact orthokeratotic hyperkeratosis and acanthosis were found in association with mites. Procnemidocoptes janssensi (Acari: Epidermoptidae, Knemidokoptinae) was identified from whole mites obtained from skin biopsies. We describe the presence, pathology, and stages of infestation for knemidokoptinid mange in a wild parrot population in New Zealand. Given the clinical and pathologic changes observed and poor knowledge of the parasite's New Zealand host and geographic distribution, further work is recommended for this and sympatric parrots, to understand relationships between the host, parasite, environment, and expression of disease. Results from this study reinforce the value of including biopsy samples for the investigation of skin disease in wild birds, particularly to link etiologic agents with pathologic changes.
M. Colter Chitwood, Morgan B. Swingen, Marcus A. Lashley, James R. Flowers, Maria B. Palamar, Charles S. Apperson, Colleen Olfenbuttel, Christopher E. Moorman, Christopher S. DePerno
Coyotes (Canis latrans) have expanded recently into the eastern US and can serve as a source of pathogens to domestic dogs (Canis lupus familiaris), livestock, and humans. We examined free-ranging coyotes from central North Carolina, US, for selected parasites and prevalence of antibodies against viral and bacterial agents. We detected ticks on most (81%) coyotes, with Amblyomma americanum detected on 83% of those with ticks. Fifteen (47%) coyotes were positive for heartworms (Dirofilaria immitis), with a greater detection rate in adults (75%) than juveniles (22%). Serology revealed antibodies against canine adenovirus (71%), canine coronavirus (32%), canine distemper virus (17%), canine parvovirus (96%), and Leptospira spp. (7%). We did not detect antibodies against Brucella abortus/suis or Brucella canis. Our results showed that coyotes harbor many common pathogens that present health risks to humans and domestic animals and suggest that continued monitoring of the coyote's role in pathogen transmission is warranted.
The meningeal worm (Parelaphostrongylus tenuis) is a parasite of white-tailed deer (Odocoileus virginianus) and is also a significant pathogen of moose (Alces alces) and other ungulates. Changes in climate or habitat may facilitate range expansion or increase the prevalence of meningeal worm infection in white-tailed deer, resulting in increased exposure to susceptible ungulates. We examined 3,730 white-tailed deer during 2002–05 to determine the prevalence and range of meningeal worm infection in North Dakota, US, and investigated whether these had changed since earlier surveys. We used multiple logistic regression to model potential effects of habitat and climate on prevalence in white-tailed deer. We also examined how habitat influences intermediate hosts by comparing gastropod abundance and microclimate among habitat types. Prevalence in deer was 14% statewide, and prevalence and geographic range had increased since the early 1990s. Natural woodlands provided the best habitat for intermediate hosts, and increases in prevalence of infection in deer may be due to recent patterns in growing-season precipitation. This study has redefined the geographic distribution of meningeal worm infection and increased understanding of how climate and habitat influence the prevalence and distribution of this parasite.
The Amargosa vole (Microtus californicus scirpensis) is a profoundly endangered rodent found only in the Central Mojave Desert, Inyo County, California, US. In 2010, severe cases of trombiculiasis, caused by larval Neotrombicula microti mites, were discovered among voles and sympatric small mammals. We evaluated Amargosa voles and sympatric rodents for infestation with N. microti December 2011–November 2012 and evaluated histopathology of ear tissue from 13 actively N. microti–infested Amargosa voles and 10 Amargosa voles with no gross evidence of current or past infestation. Rodents with current infestation had mites visible on tissue, typically ear pinnae, whereas mites were not seen on rodents with presumptive past infestation, but some of these animals had gross tissue scarring and loss consistent with healing from infestation. Ears from infested voles had severe granulocytic and necrotizing dermatitis, most associated with stylostome fragments, whereas few lesions were present in grossly uninfested voles. There was no association between body condition and infestation or severity of lesions. Significantly more voles were infested (37%) with N. microti than sympatric rodents (3%), suggesting that sympatric rodents do not serve as an important source of N. microti exposure to voles. Although this chigger infestation was common and induced severe localized pathology, we did not detect a fitness cost to infestation and recommend further evaluation of the disease to discern its significance in this conservation context.
Understanding causes of death can aid management and recovery of endangered bird populations. Toward those ends, we systematically examined 300 carcasses of endangered Hawaiian Geese (Nene; Branta sandvicensis) from Hawaii, Maui, Molokai, and Kauai between 1992 and 2013. The most common cause of death was emaciation, followed by trauma (vehicular strikes and predation), and infectious/inflammatory diseases of which toxoplasmosis (infection with Toxoplasma gondii) predominated. Toxicoses were less common and were dominated by lead poisoning or botulism. For captive birds, inflammatory conditions predominated, whereas emaciation, trauma, and inflammation were common in free-ranging birds. Mortality patterns were similar for males and females. Trauma predominated for adults, whereas emaciation was more common for goslings. Causes of death varied among islands, with trauma dominating on Molokai, emaciation and inflammation on Kauai, emaciation on Hawaii, and inflammation and trauma on Maui. Understanding habitat or genetic-related factors that predispose Nene (particularly goslings) to emaciation might reduce the impact of this finding. In addition, trauma and infection with T. gondii are human-related problems that may be attenuated if effectively managed (e.g., road signs, enforcement of speed limits, feral cat [Felis catus] control). Such management actions might serve to enhance recovery of this endangered species.
An adult male striped dolphin (Stenella coeruleoalba) stranded alive at Arico, Tenerife, Canary Islands, Spain. The dolphin died shortly after stranding, and a complete postmortem examination was performed. The most remarkable gross findings were two fleshy masses of approximately 1 cm diameter, near the tip of the penis. These masses were composed of hyperplastic epithelial cells with pigmentary incontinence. Ballooning degeneration and margination of chromatin was observed within the stratum corneum of the epidermis. A universal nested PCR assay that amplifies a conserved region within the polymerase gene of Herpesviridae was positive. The sequenced product was most closely related to a gammaherpesvirus that shared nucleotide identities of 93% with penile lesions from Atlantic and Mediterranean bottlenose dolphins (Tursiops truncatus). This similarity supports the hypothesis of sexual transmission between species.
As the number of free-living wild boars (Sus scrofa L.) continues to rise in Slovakia, the probability of pathogen transmission between susceptible species increases. We investigated the distribution and genetic characterization of porcine parvovirus type 3 (PPV3), porcine circovirus type 2 (PCV2), and their coinfection in wild boars. Among 194 animals tested, 19.1% were positive for PPV3 and 43.8% for PCV2. Similar rates of coinfection with both viruses reaching 11.0% and 11.8% were observed in juvenile and mature wild boars, respectively. Phylogenetic analysis of PPV3 sequences from VP1 and NS1 genomic regions revealed a close genetic relationship among isolates from Slovakia and those sampled worldwide. Prevalence of PCV2 in wild boars was lower than that reported in domestic pigs in Slovakia. The PCV2 variants originating from sylvatic and domestic hosts in Slovakia were grouped in the same clusters, namely PCV2b-1A/1B and PCV2a-2D.
Medical records of 931 reptiles admitted to the Australian Wildlife Health Centre, Healesville Sanctuary, Healesville, Victoria, Australia, from 2000 to 2013 were reviewed to determine the causes of morbidity and mortality. Thirty-nine species were presented; the most common were the common long-neck turtle (Chelodina longicollis; n = 311, 33.4%), the eastern bluetongue lizard (Tiliqua scincoides; n = 224, 4.1%), the blotched bluetongue lizard (Tiliqua nigrolutea; n = 136, 14.6%), and the lowland copperhead (Austrelaps superbus; n = 55, 5.9%). Trauma was the most significant reason for admissions, accounting for 73.0% of cases. This was followed by not injured (11.7%), displacement (6.4%), snake removal (4.2%), human interference (3.1%), introduced species (1.1%), sick/diseased (0.2%), and illegal pet (0.2%). Within the category of trauma, impact with motor vehicle (41.0% of trauma cases) and domestic animal attack (33.2% of trauma cases) were the most common subcategories. Our results indicate that indirect anthropogenic factors are a significant cause of morbidity and mortality in Australian reptiles.
Trypanosomaevansi is a protozoan blood parasite and etiologic agent of “surra,” a disease affecting a wide range of domestic and wild mammals, some identified as potential reservoirs. Although T. evansi has been detected in several small wild rodent species, their role in the epidemiology of surra is unclear. There is molecular evidence of T. evansi in wild rodents in Asia, but it is not known whether they can carry the parasite for sufficient time to significantly contribute to the epidemiology of surra. We assessed the susceptibility of the Oriental house rat (OHR; Rattus tanezumi) to T. evansi infection. Five adult male OHRs trapped in Bangkhen district, Bangkok, Thailand, and five laboratory Wistar rats (Rattus norvegicus) as positive controls, were experimentally infected with a local strain of T. evansi. The five controls and three of the five OHRs were highly susceptible and rapidly exhibited the high levels of parasitemia usually observed in Wistar rats. They died or were euthanized just prior to expected death. Two OHRs presented fluctuating levels of parasitemia, without obvious clinical signs, throughout 40 d of monitoring. These results highlight the moderate susceptibility of some OHRs and their ability to carry the infection over time. Along with the molecular evidence of T. evansi in captured OHRs (demonstrated elsewhere), our results bring new information on the potential role of OHRs in the complex epidemiology of surra.
Blood samples are often collected from free-ranging wildlife for antibody detection. However, filter-paper (FP) strips are more cost efficient and easy to collect and store. We evaluated trapper-collected FP strips and body-cavity blood for canine distemper (CDV) and parvovirus (CPV-2) antibody detection in raccoons (Procyon lotor) and coyotes (Canis latrans). From 2008 to 2010, licensed trappers near Madison and Milwaukee, Wisconsin, US collected paired samples from harvested animals. Canine distemper antibodies were detected using virus neutralization and parvovirus antibodies were detected using hemagglutination inhibition. Titers ≥1:32 for CDV and ≥1:25 for CPV-2 were considered evidence of exposure. Using Cohen's kappa test of agreement, FP strip titers agreed with sera for CDV in coyotes (n = 28, K = 0.772) and raccoons (n = 29, K = 0.858) and for CPV-2 in coyotes (n = 40, K = 0.775) and raccoons (n = 70, K = 0.646). However, raccoons determined to be exposed to CPV-2 from sera were unexposed by FP strips in 35% of the samples. Titer results may be affected by quality and volume of blood samples, interval between collection and processing, small sample sizes, and diagnostic testing procedures. Filter-paper strips can be useful for detecting CDV and CPV-2 exposure in coyotes and raccoons with correct field sample collection and appropriate diagnostic testing procedures.
Sarcoptic mange occurs in free-ranging wild boar (Sus scrofa) but has been poorly described in this species. We evaluated the performance of a commercial indirect enzyme-linked immunosorbent assay (ELISA) for serodiagnosis of sarcoptic mange in domestic swine when applied to wild boar sera. We tested 96 sera from wild boar in populations without mange history (“truly noninfected”) collected in Switzerland between December 2012 and February 2014, and 141 sera from free-ranging wild boar presenting mange-like lesions, including 50 live animals captured and sampled multiple times in France between May and August 2006 and three cases submitted to necropsy in Switzerland between April 2010 and February 2014. Mite infestation was confirmed by skin scraping in 20 of them (“truly infected”). We defined sensitivity of the test as the proportion of truly infected that were found ELISA-positive, and specificity as the proportion of truly noninfected that were found negative. Sensitivity and specificity were 75% and 80%, respectively. Success of antibody detection increased with the chronicity of lesions, and seroconversion was documented in 19 of 27 wild boar sampled multiple times that were initially negative or doubtful. In conclusion, the evaluated ELISA has been successfully applied to wild boar sera. It appears to be unreliable for early detection in individual animals but may represent a useful tool for population surveys.
The collection and consumption of animal carcasses is a common activity in forested areas of the Congo River basin and creates sustainability, conservation, and health concerns. Residents of the Tshuapa District reported collecting the remains of 5,878 animals from >30 species when surveyed about their wildlife consumption habits. Carcasses were discovered in varying degrees of decomposition and were often consumed at home or sold in local markets. The most commonly collected animals were Cricetomys gambianus (Northern giant pouched rat), Cercopithecus ascanius (red-tailed monkey), and Heliosciurus rufobrachium (red-legged sun squirrel). Many of the species recorded may be hosts of zoonotic pathogens, creating concern for spillover events.
Trichomonas gallinae is a protozoan parasite commonly found in columbids, passerines, and several raptor species. Although T. gallinae is thought to spread between individuals and across species through shared water sources, little research has been conducted regarding the persistence of T. gallinae in the environment. To determine the persistence of T. gallinae in various communal water sources, we inoculated 1×106 trichomonads into 500 mL samples of distilled water, quarry water, bird bath water, and rain barrel water in two replicates. Aliquots of 0.5 mL were collected from each source at −1, 0, 15, 30, and 60 min; aliquots were incubated at 37 C and examined for trichomonads by light microscopy for five consecutive days. Live trichomonads were observed in all samples and at all sampling times except prior to inoculation (−1 min). The pH of water sources ranged from an average of 5.9 to 7.4 postsampling. Our findings indicate that T. gallinae can persist for up to 60 min in various water treatments and thus be infectious for birds drinking T. gallinae-contaminated water.
Recent detection of a European-type haplotype of the cestode Echinococcus multilocularis in a newly enzootic region in British Columbia prompted efforts to determine if this haplotype was present elsewhere in wildlife in western Canada. In coyote (Canis latrans) definitive hosts in an urban region in central Saskatchewan (SK), we found a single haplotype of E. multilocularis that was most similar to a haplotype currently established in the core of this parasite's distribution in Europe and to the European-type haplotype found in coyotes and a dog (Canis lupus familiaris) in British Columbia. We found six haplotypes of E. multilocularis from deer mouse (Peromyscus maniculatus) intermediate hosts in southwestern SK that were closely related to, and one haplotype indistinguishable from, a haplotype previously reported in the adjacent north-central US. This is a higher level of diversity than has previously been recognized for this parasite, which suggests that the population native to central North America is well established, rather than a recent introduction from the Arctic. These findings, in combination with recent cases of alveolar hydatid cysts in dogs in Canada, raise concerns that European haplotypes of E. multilocularis may be increasing in distribution within wildlife in Canada. European haplotypes may pose greater risks to veterinary and human health than native haplotypes long established in central North America.
The rat lungworm (Angiostrongylus cantonensis) is a parasitic nematode that causes rat lungworm disease. It is the leading cause of eosinophilic meningitis and is a zoonotic health risk. We confirmed the presence of A. cantonensis using species-specific, quantitative PCR in 18 of 50 (36%) giant African land snails (Lissachatina fulica) collected from Miami, Florida, US in May 2013. These snails were collected from seven of 21 core areas that the Florida Department of Agriculture and Consumer Services monitor weekly. Rat lungworms have not previously been identified in these areas. Duplicate DNA extractions of foot muscle tissue from each snail were tested. Of the seven core areas we examined, six were positive for A. cantonensis and prevalence of infection ranged from 27% to 100%. Of the 18 positive snails, only five were positive in both extractions. Our results confirm an increase in the range and prevalence of rat lungworm infection in Miami. We also emphasize the importance of extracting sufficient host tissue to minimize false negatives.
Avian bornaviruses, recently described members of the family Bornaviridae, have been isolated from captive parrots and passerines as well as wild waterfowl in which they may cause lethal neurologic disease. We report detection of avian bornavirus RNA in the brains of apparently healthy gulls. We tested 439 gull brain samples from 18 states, primarily in the northeastern US, using a reverse-transcriptase PCR assay with primers designed to detect a conserved region of the bornavirus M gene. Nine birds yielded a PCR product of appropriate size. Sequencing of PCR products indicated that the virus was closely related to aquatic bird bornavirus 1 (ABBV-1). Viral RNA was detected in Herring Gulls (Larus argentatus), Ring-billed Gulls (Larus delawarensis), and Laughing Gulls (Leucophaeus atricilla). Eight of the nine positive birds came from the New York/New Jersey area. One positive Herring Gull came from New Hampshire. Histopathologic examination of one well-preserved brain from a Herring Gull from Union County New Jersey, showed a lymphocytic encephalitis similar to that observed in bornavirus-infected parrots and geese. Bornavirus N protein was confirmed in two Herring Gull brains by immunohistochemistry. Thus ABBV-1 can infect gulls and cause encephalitic brain lesions similar to those observed in other birds.
Wildlife can act as long-term asymptomatic reservoirs for zoonotic bacteria, such as Salmonella. The prevalence and antimicrobial-susceptibility profiles of Salmonella spp. were assessed in 263 cases in wildlife from 22 animal orders from a wildlife rehabilitation center in Catalonia (NE Spain), September 2013–May 2014. Eleven of 263 tested animals were positive for Salmonella spp., representing an overall prevalence of 4.2%. Prevalences by taxonomic categories were 2% in mammals, 4.7% in birds, and 4.5% in reptiles. By species, one each of European hedgehog (Erinaceus europeus; from a sample of n = 26), Eurasian Eagle Owl (Bubo bubo; n = 2), Barn Owl (Tyto alba; n = 3), Tawny Owl (Strix aluco; n = 20), Egyptian Vulture (Neophron percnopterus; n = 1), Griffon Vulture (Gyps fulvus; n = 1), and Hoopoe (Upupa epops; n = 2), and two each Common Kestrels (Falco tinnunculus; n = 16) and pond sliders (Trachemys scripta; n = 25) were positive for Salmonella. By serotyping, seven of eleven isolates were classified as S. enterica subsp. enterica serovar Typhimurium, and five of seven belonged to the monophasic variant 4,12:i:-. All the monophasic variants were isolated from birds (4/5 in raptors) and showed a multidrug-resistance (MDR) profile to at least ampicillin, streptomycin, sulfonamide, and tetracycline (R-type ASSuT), and up to 12 antibiotics. The large proportion of S. Typhimurium monophasic MDR strains detected in wildlife never treated with antibiotics, especially in raptors, adds more complexity to the epidemiologic control of one of the most frequent serovars involved in human and livestock infection.
P. Ryan Clarke, William H. Edwards, Steven G. Hennager, Jean F. Block, Angela M. Yates, Eric Ebel, Douglas J. Knopp, Antonio Fuentes-Sanchez, Jessica Jennings-Gaines, Rebecca L. Kientz, Marilyn Simunich
Brucellosis (caused by the bacterium Brucella abortus) is a zoonotic disease endemic in wild elk (Cervus canadensis) of the Greater Yellowstone Ecosystem, US. Because livestock and humans working with elk or livestock are at risk, validated tests to detect the B. abortus antibody in elk are needed. Using the κ;-statistic, we evaluated the buffered, acidified plate antigen (BAPA) assay for agreement with the results of the four serologic tests (card test [card], complement fixation test [CF], rivanol precipitation plate agglutination test [RIV], standard plate agglutination test [SPT]) that are approved by the US Department of Agriculture for the detection of the B. abortus antibody in elk. From 2006 to 2010, serum samples collected from elk within B. abortus–endemic areas (n = 604) and nonendemic areas (n = 707) and from elk culture-positive for B. abortus (n = 36) were split and blind tested by four elk serum diagnostic laboratories. κ;-Values showed a high degree of agreement for the card (0.876), RIV (0.84), and CF (0.774) test pairings and moderate agreement for the SPT (0.578). Sensitivities for the BAPA, card, RIV, CF, and SPT were 0.859, 0.839, 0.899, 1.00, and 0.813, whereas specificities were 0.986, 0.993, 0.986, 0.98, and 0.968, respectively. The positive predictive values and the negative predictive values were calculated for 2.6%, 8.8%, and 16.2% prevalence levels. These findings suggest the BAPA test is a suitable screening test for the B. abortus antibodies in elk.
We examined sera from snowshoe hares (Lepus americanus) livetrapped in the northern Greater Yellowstone Area (GYA), US, for antibodies to Brucella abortus, Francisella tularensis, and snowshoe hare virus (SSHV). Zero of 90, 0 of 67, and 40 of 100 samples were antibody positive for B. abortus, F. tularensis, and SSHV, respectively. Hares were trapped from 2009 to 2012, and of the six animals that were captured twice with at least 1 yr between captures, four developed antibody to SSHV, indicating active exposure to the agent. These findings suggest snowshoe hares in the GYA do not play a significant role as a reservoir of B. abortus, but do maintain the zoonotic, encephalitic SSHV in the population.
Brian R. Amman, Cesar G. Albariño, Brian H. Bird, Luke Nyakarahuka, Tara K. Sealy, Stephen Balinandi, Amy J. Schuh, Shelly M. Campbell, Ute Ströher, Megan E. B. Jones, Megan E. Vodzack, DeeAnn M. Reeder, Winyi Kaboyo, Stuart T. Nichol, Jonathan S. Towner
In August 2012, a wildlife biologist became ill immediately following a 6-wk field trip to collect bats and rodents in South Sudan and Uganda. After returning to the US, the biologist was admitted to the hospital with multiple symptoms including fever, malaise, headache, generalized myalgia and arthralgia, stiffness in the neck, and sore throat. Soon after admission, the patient developed a maculopapular rash and oropharynx ulcerations. The patient remained hospitalized for 14 d. Several suspect pathogens, including viral hemorrhagic fever viruses such as Ebola viruses and Marburg viruses, were ruled out through standard diagnostic testing. However, deep sequencing and metagenomic analyses identified a novel paramyxovirus, later named Sosuga virus, in the patient's blood. To determine the potential source, bat tissues collected during the 3-wk period just prior to the onset of symptoms were tested for Sosuga virus, and several Egyptian rousette bats (Rousettus aegyptiacus) were found to be positive. Further analysis of archived Egyptian rousette tissues collected at other localities in Uganda found additional Sosuga virus–positive bats, suggesting this species could be a potential natural reservoir for this novel paramyxovirus.
Northern Bobwhites (Colinus virginianus) have been in decline throughout the southeastern US. Prevalence of Trichomonas gallinae in wild bobwhites is unknown, although T. gallinae caused morbidity and mortality in experimentally infected bobwhites. Many species of Columbidae (pigeons and doves) in Texas are hosts to T. gallinae. Bobwhites potentially may become exposed to this protozoan through supplemental feed or water sources contaminated by columbids infected with T. gallinae. All of 506 bobwhites collected in Oklahoma and Texas, 2011–13, were PCR negative for T. gallinae. These data suggest T. gallinae is not contributing to the population decline of bobwhites in this region.
Using a fecal flotation technique, we detected three genera of endoparasites in the critically endangered Waved Albatross (Phoebastria irrorata) of Galápagos. These genera were Contracaecum, Tetrabothrius, and Cardiocephaloides. Juvenile albatrosses were more likely to be infected than adults, but we found no effect of sex or mass on infection probability.
Rosiléia Marinho de Quadros, João Fábio Soares, Juliane Scharlau Xavier, Celso Pilati, Jocelim Lotário da Costa, Bruno Alonso Miotto, Luiz Claudio Miletti, Marcelo B. Labruna
Rangeliavitalii is a piroplasmid that causes canine rangeliosis, a severe hemorrhagic disease of domestic dogs in South America. We report about R. vitalii infecting a pampas fox (Lycalopex gymnocercus). The fox, which developed a fatal illness, was also infected by Hepatozoon canis and Capillaria hepatica.
A male Rio Grande Wild Turkey (Meleagris gallopavo intermedia) living in semidomestication was submitted for necropsy. Emaciation, a greatly enlarged heart, and chronic passive congestion of the liver were present. Dilated cardiomyopathy occurs in domestic turkey flocks but has not been reported in Wild Turkeys.
We report granulomatous lymphadenitis in red deer (Cervus elaphus) in Portugal caused by coinfection with Corynebacterium pseudotuberculosis, Mycobacterium bovis, and Mycobacterium avium subsp. paratuberculosis, as demonstrated by molecular methods.
We provide hematologic (n = 34) and biochemical (n = 30) blood values for wild-caught Australian bush rats (Rattus fuscipes). Hematology values have similar range limits compared with other rat species. Biochemistry values for glucose, alanine transaminase, aspartate aminotransferase, and creatine kinase have higher maximum ranges compared with other rats.
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