Wildlife Diseases and Toxicology II

Contributed Paper
ROOM: HCCC, Room 20
SESSION NUMBER: 67
 

12:50PM Ground-Dwelling Songbirds as Competent Carriers and Reservoirs of Lyme Borreliosis
Christopher M. Lituma; Amanda Hill; Matthew E. Wilson; Jean Meade
The One Health initiative, focuses on increasing interdisciplinary collaboration between the fields of human medicine, veterinary medicine, and environmental health, and considers zoonotic diseases to be a primary concern due to their impact on both humans and animals. Lyme disease is the most common vector-borne disease in the United States. It is spread across species through interactions bewteen ticks and hosts, including small and large mammals, birds, reptiles, and humans. Both Borrelia burgdorferi (the causative agent of Lyme disease) and Ixodes scapularis (the primary vector for Lyme disease in the Northeastern United States) are expanding their ranges. Our objective is to understand the role of migratory songbirds in the geographic expansion of Lyme disease. Specifically, we documented tick infestation rates on ground-dwelling songbirds, Borrelia burdorferi prevalence of ticks collected from songbirds, as well as prevalence collected from avian blood. During Spring and Fall of 2017, we captured birds of 14- ground-dwelling species at 3 banding stations: Braddock Bay Bird Observatory, NY; Powdermill Avian Research Center, PA; Allegheny Front Bird Migration Observatory, WV. Ticks (nymphs) were removed from all infested birds, and blood was drawn from a random sample of both tick infested and non-infested birds. We used PCR to detect Borrelia burgdorferi in the ticks and avian blood. Our most common species were; common yellowthroat (Geothlypis trichas, 33% of total captures), and gray catbird (Dumetella carolinensis, 21% of total captures). The prevalence of birds carrying ticks was 35.58% (132/371). Of the 284 ticks removed from the 371 birds, 25.35% (72/284) tested PCR positive for Borrelia burgdorferi. Borrelia burgdorferi was detected in 7.87% (14/178) of the avian blood samples collected. These results indicate that ground-dwelling migratory songbirds are competent carriers of the primary vector and causative agent of Lyme disease, therefore, they play a role in its geographic expansion.
1:10PM Influenza D Virus Transmission in Feral Swine
Fred L. Cunningham; Lucas Ferguson; Kaijian Luo; Alicia K. Olivier; Sherry Blackmon; Katie Hanson-Dorr; Hailiang Sun; John Baroch; Mark Lutman; Bianca Quade; William Epperson; Richard Webby; Thomas J. Deliberto; Xiu-Feng Wan
Influenza D virus (IDV) has been identified in domestic cattle, swine, camelid, and small ruminant populations across North America, Europe, Asia, South America, and Africa. A serological survey of 256 feral swine samples collected 2012-2013 found 19.1% seropositive for IDV. Of 96 archived influenza A positive samples collected 2010-2013, 42.7% were also seropositive for IDV. To test the transmissibility of IDV in feral swine, we randomly separated 26 captive feral swine into 3 groups: inoculated (IDV, n = 12), contact (n = 8), and control (saline, n = 6). Pens contained 1 or 2 inoculated animals and 1 contact animal. Control feral swine were housed separately and remained negative for IDV. At 2 days post inoculation (dpi), a contact animal was introduced into pens with inoculated feral swine. We collected nasal washes and blood on days 0, 3, 5, 7, 9, 11and 21 dpi. Pigs were euthanized and necropsied 3, 5, 7, 9, 11 and 21 dpi to collect tissue samples from the respiratory tract. Viral titration of nasal washes showed that, at 3 dpi, 7 of 12 (58.3%) D/46N-inoculated swine shed virus. At 5 dpi, 6 of the 8 (75%) remaining virus-inoculated swine shed virus. The remaining 5 virus-inoculated swine did not shed virus by 7 dpi. Hemagglutination inhibition assay results indicated that 7 of 11 (63.6%) of the inoculated animals seroconverted at 5 dpi, and the remaining virus-inoculated animals seroconverted at 7 dpi. Titrations in tissues indicated virus in the nasal turbinate, soft palate, trachea and lung. The transmissibility of IDV through direct contact is similar to that in domestic swine; but less efficient than that in cattle. Given the limited transmissibility of IDV in feral swine, we speculate that feral swine could have additional opportunities for exposure to IDV from other species such as cattle.
1:30PM Gut Microbial Diversity Decreases with Urbanization and Mediates the Prevalence of a Zoonotic Pathogen in a Wading Bird
Sonia M. Hernandez; Maureen Murray; Emily W. Lankau; Anjelika Kidd; Erin Lipp
The gut microbiome influences many aspects of host health, including metabolism and susceptibility to pathogen colonization. These relationships are thought to be largely mediated by microbiome composition and diversity, both of which are influenced by host diet, age, and environment. Although studies of humans and livestock have demonstrated the importance of these relationships, the drivers and health consequences of microbiome differences in wildlife have received less attention. American white ibises (Eudocimus albus) experience substantial shifts in diet when residing in increasingly urbanized habitats in south Florida, primarily through increased consumption of food provided by people in urban parks (e.g. bread and other processed foods rich in carbohydrates). We assessed the effects of habitat use, bread consumption, and age on microbiome composition and diversity, and tested whether ibises with less diverse microbial communities were more likely to be shedding Salmonella enterica, a zoonotic enteric pathogen we have tracked on ibis for 5 years. We sampled 82 free-living ibis from 16 sites along an urbanization gradient in south Florida, USA. We aged ibis using plumage and measured assimilation of bread using stable isotope analyses of red blood cells. We isolated Salmonella spp. from fresh fecal samples and characterized the gut microbiome from frozen feces using 16S rRNA Illumina sequencing. Ibises captured at more urbanized sites had a lower proportion of Firmicutes but higher proportions of Bacteroidetes, Proteobacteria, and TM7, and this shift was primarily associated with higher anthropogenic food consumption. The average Shannon diversity of genera detected in ibis gut microbiomes was significantly negatively associated with urbanization and bread consumption, positively associated with age, and lower diversity was associated with higher Salmonella prevalence. As species adapt to urban/disturbed environments, understanding the link between their diet, gut microbial community composition and diversity, and health and pathogen susceptibility is paramount.
1:50PM Evolutionary Rescue of Little Brown Bat Populations Infected Bywhite-Nose Syndrome
Sarah Gignoux-Wolfsohn; Malin Pinsky; Kathleen Kerwin; Nina Fefferman; Brooke Maslo
Some populations of the little brown bat (Myotis lucifugus) appear to be stabilizing in the years following catastrophic declines due to white-nose syndrome (WNS). Recent modeling has suggested that this may be due to a selective sweep of the pathogen through bat populations in favor of more robust genotypes. If remnant infected colonies contain genetically resistant individuals that continue to survive and reproduce, population dynamics could revert to positive growth, a phenomenon known as evolutionary rescue. To better understand the evolutionary potential of infected bat populations, we collected DNA samples from little brown bats from three locations: New Jersey, New York, and Vermont, USA. For each site, we collected 30 samples each from individuals representing the genetic variation within the population both before and after disease emergence. We then used low-coverage whole genome sequencing to characterize the genetic makeup of populations before and after WNS-caused population declines. We find strong evidence of disease-induced selection for certain genotypes, including both quantifiable genetic differentiation between populations before and after WNS arrival, as well as regions of the genome that are likely under selection (as determined by Fst outliers). These regions code for genes associated with fitness and may be involved in genetically-determined behavioral changes in remnant populations that allow them to survive WNS infection. These results will help inform management strategies for both remnant populations and populations that have not yet been exposed to WNS.
2:10PM Are There Canonical Decision Problems in Managing Emerging Infectious Diseases of Wildlife?
Riley F. Bernard; Evan H. C. Grant
Emerging infectious diseases (EIDs) of wildlife are notoriously difficult to manage, leading to reactive and often ineffective management strategies. Currently, two fungal pathogens, Pseudogymnoascus destructans (Pd) and Batrachochytrium salamandrivorans (Bsal), are causing declines in novel host species, leaving managers with little time, and few options, to respond. As risk of fungal pathogens increases, necessitating the need for an improved response model, we aimed to identify the underlying challenges that often lead to delayed rather than proactive disease management actions. Using an online survey platform, we queried wildlife managers, motivated by Pd and Bsal, regarding their management concerns, objectives, and disease mitigation actions. We also characterized their impediments to initiating disease mitigation actions to identify if there are characteristics of EID management that are shared across agencies and pathogens. We received 91 Pd and 81 Bsal responses from state, federal and provincial agencies. Across both pathogens, 52% of managers felt the most pressing concern was the current or possible loss of susceptible species. However, this concern did not necessarily lead to proactive management, with most managers stating the need to consider multiple management objectives such as multi-use management, public use, and other species of conservation concern. Although managers would consider initiating proactive responses to EIDs, the amount of uncertainty and associated risk with untested treatments often outweighs the fear of species loss. By formally framing management problems as decisions, managers can effectively identify possible proactive solutions and recognize context-specific constraints, such as agency mandates, trade-offs among other mission elements, and relevant uncertainties that aid in recognizing and sustaining conservation success through proactive management actions. Although Pd and Bsal affect different taxa, we identified aspects of each decision problem that were shared regardless of pathogen, region, or agency, suggesting that there are indeed canonical decision problem elements for fungal pathogen management.
2:30PM Refreshment Break
3:20PM Better Bullets to Shoot Small Mammals Without Poisoning Scavengers
Michael McTee
Millions of small mammals are shot each year for recreation and damage control. Scavengers that ingest the carcasses can be poisoned if lead bullets are used. Bullets that deposit little or no lead exist, but their performance and potential risk to leave lead in carcasses is understudied. Additionally, the species that scavenge these carcasses need to be identified. We collected carcasses of Columbian ground squirrels (Urocitellus columbianus) that were shot at farms and ranches in Idaho and Montana, USA. Shooters used .17 HMR (Hornady Magnum Rimfire), .22 LR (long rifle), and .223 Rem (Remington) rifles in both expanding and nonexpanding lead and nonlead bullets. We also documented whether the bullets instantly incapacitated ground squirrels. In additional areas, we placed remote cameras near carcasses to photograph scavenging wildlife. For each of the different lead bullets used, there was residual lead in at least one-third of carcasses. Expanding bullets in the .17 HMR and .223 Rem left the highest average concentrations of lead in ground squirrels, with an average of 23.6 mg and 91.2 mg lead/carcass, respectively. Nonlead bullets incapacitated as well as lead bullets. Remote cameras captured various scavengers, including rodents, badgers, and several species of hawks. Our results indicate that shooting small mammals likely exposes a diverse scavenger community to lead. This risk can be eliminated if shooters would use nonlead bullets.
3:40PM The Effects of Dermal Exposure to Poly- and Perfluoroalkyl Substances on Post-Metamorphic Amphibians
Sarah A. Abercrombie; Michael Iacchetta; Chloe de Perre; Maria S. Sepúlveda; Linda S. Lee; Jason T. Hoverman
Poly- and perfluoroalkyl substances (PFASs) are distributed throughout ecosystems globally and have been targeted for regulation due to their persistence in the environment, widespread accumulation in both humans and wildlife, and potential for a variety of adverse effects. While PFAS toxicity has been examined in a variety of taxa (e.g., birds, mammals, fish), research on amphibians is limited. We examined the effects of PFAS exposure via contaminated substrate on the survival and growth of juvenile American Toads (Anaxyrus americanus), Eastern Tiger Salamanders (Ambystoma tigrinum) and Northern Leopard Frogs (Lithobates pipiens). Treatments included perfluorooctanoic acid (PFOA), perfluoroocatane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), and 6:2 fluorotelomer sulfonate (6:2 FTS) at concentrations of 10, 100, and 1000 parts per billion, and a control treatment. Individuals were uniquely identified to assess percent changes in mass and snout-vent length (SVL) over the 30-d experiment. While there was no influence of PFASs on survival or mass of the species, we found significant effects on SVL. Salamanders exposed to PFASs generally exhibited 5 to 10% greater growth in SVL compared to the control, while frogs and toads displayed the opposite pattern. Effects on SVL growth were strongest with exposure to 6:2 FTS and weakest with PFOA. There was limited evidence for a dose-response relationship for the PFASs. We also applied a residual condition index (RCI) to evaluate relative body condition, with controls as our reference RCI. Salamanders showed decreased RCI for all treatments with the exception of PFOS, frogs decreased regardless of treatment, and toads were highly variable. While additional research is needed to determine the mechanisms underlying the contrasting effects of PFASs on salamanders and anurans, our work demonstrates that PFASs can have sublethal effects on amphibians.
4:00PM Trophic Magnification of Legacy and Alternative Flame Retardants in a Northwestern Atlantic Food Web
Hillary R. Marler; Douglas H. Adams; Clayton K. Nielsen; Da Chen
Due to bans and voluntary phase outs of commercial polybrominated diphenyl ether (PBDE) flame retardant (FR) mixtures, several chlorinated and brominated flame retardants have been developed. These alternative FRs are currently subject to increased production and use to meet flammability standards for consumer products. PBDEs have been well studied and are known to biomagnify in many different food webs around the world. Increasing numbers of studies are also demonstrating that some of the alternative FRs can also biomagnify in a variety of terrestrial, freshwater, and marine systems. We investigated the trophic magnification of alternative FRs in a Northwestern Atlantic food web. We utilized tissue samples (liver, muscle, and whole body composites) from a variety of species, from invertebrates to apex predators, for chemical residue and stable isotope analysis. All samples were collected from coastal and offshore waters of the northeastern United States between 2010 and 2014. Median concentrations of total PBDEs ranged from 18 ng/g lipid weight to 800 ng/g lipid weight for the species studied. Median concentrations of total Dechlorane plus related compounds ranged from 1 ng/g lipid weight to 44 ng/g lipid weight. Trophic levels represented ranged from 1.7 to 4.6 as determined by δ15 nitrogen analysis. Trophic magnification factors (TMFs) were >1 for legacy and alternative flame retardants, indicating that magnification of both PBDEs and their replacements is occurring in this food web. Total PBDE magnification (4.1) was higher than total Dechlorane plus related compound magnification (2.6), although TMFs for individual congeners and analogues in each group varied. Our research indicates that alternative FRs should be considered in future biomonitoring and assessment of contaminants in the Northwestern Atlantic Ocean.
4:20PM Effects of Mycoplasma Ovipneumoniae and Other Factors on Adult Female Bighorn Survivorship Following a Pneumonia Epizootic and Die-Off in the Mojave Desert, California
Daniella J. Dekelaita; Clinton W. Epps; Kelley M. Stewart; James Sedinger; Jenny Powers; Ben Gonzales; Regina Vu; Neal Darby; Debra Hughson
In May and June of 2013, a pneumonia outbreak linked to the pathogen Mycoplasma ovipneumoniae (M. ovi) led to an all-age die-off of desert bighorn sheep (O. c. nelsoni) at Old Dad Peak (Kelso Mountains) in the Mojave Desert, California. Subsequently, symptoms of respiratory disease were observed in multiple ranges throughout the system. Our objective was to investigate post-outbreak survivorship of adult female bighorn across 9 populations for 3.5 years in the Mojave Desert, and evaluate the effect of M. ovi infection on seasonal survival, while testing effects of range-specific factors that could potentially drive differences in herd response (i.e., forage quality, fall and winter precipitation, and population size). We collared and tested the disease status of 115 adult females, tracked survival via radio collars, and used the known-fates module in Program MARK to model seasonal survival from November 2013 to March 2017. We found that infection at time of capture had the strongest negative effect on survival, followed by population size and winter precipitation, with population size having a slightly stronger negative effect per unit increase than winter precipitation, and the effect of infection being nearly 30% stronger than either of the latter. Fall forage quality had the only positive effect on survival, and the magnitude of the effect as represented by NDVI was less than that of infection but greater than population size and winter precipitation per unit increase. Our results suggest that adults who were infected with M. ovi at capture had lower survival, likely due to chronic infection, but range-specific factors may have further influenced disease impacts.
4:40PM Supplementation of Lutein Improved Antioxidant Status and Immunity for Ex-Situ Conservation of Indian Leopard
Sharad M. Durge; Asit Das; S. K. Saha; Ankur Saxena; P. Singh; A. K. Sharma; A. K. Verma
Natural diet of Indian leopard (Panthera pardus fusca) contains ungulates, primates, rodents and birds in the wild; while they are being fed buffalo meat in ex-situ conservation. Wild animals are natural accumulator of carotenoids in their body unlike the domestic buffalo. Felids have highest level of circulating carotenoids; which are potent antioxidants and immune-modulator. Hence, the study was planned with an objective to evaluate effect of lutein supplementation on antioxidant status and immunity of Indian leopard. Total nine Leopards (5 Male and 4 Female, age 3-15 years) were randomly distributed in three groups A, B and C, based on replicated Latin square design. All groups were fed fresh buffalo meat on bone at 2-2.5 kg/d/animal. Group A was fed no supplement; however, groups B and C were supplemented with 20 and 40 ppm of lutein on dry matter basis. Each trial was of 25 d including 4 d of collection period. The feed dry matter intake was similar in all three groups which was 37.4, 39.0 and 36.5 g/kgW0.75 in group A, B and C, respectively; whereas, the carotenoids intake was significantly higher (P<0.001) in lutein supplemented groups B and C (788.9 and 1467.1 µg/kgW0.75) compared to control group A (7.11 µg/kgW0.75) and showed a linear trend of increase with lutein supplementation. Serum concentration of total immunoglobulin (µg/mL) and the activity of SOD was significantly (P<0.005) higher in group B than A and C. The lymphocyte stimulation index was significantly higher (P<0.001) in groups B and C, lutein supplemented group as compared to group A. There was a linear decreased (P<0.001) in level of fecal Cortisol with supplementation of lutein in group B and C respectively. It was concluded that the supplementation of 20 ppm lutein alleviates the antioxidant and cellular immune response of lymphocyte and helps to combat stress.

 

Contributed Paper
Location: Huntington Convention Center of Cleveland Date: October 10, 2018 Time: 12:50 pm - 5:00 pm