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USGS National Wildlife Health Center

September 9-12, 2018

Update to the Association of Fish and Wildlife Agencies from the USGS National Wildlife Health Center

INSIDE THIS UPDATE:

Avian Influenza 1 Amphibian Diseases 2 Chronic Wasting Disease 3 Harmful Algal Blooms 4 Vaccine Development 5 White-Nose Syndrome 6

We’re Here to Assist The USGS National Wildlife Health Center (NWHC) assists state, federal and tribal natural resource partners in the investigation of wildlife morbidity and mortality events in the United States. For routine services, the only cost incurred by partners is for collection and shipment of carcasses to the NWHC. Analyses for each diagnostic case are initiated within an average of 48 hours following receipt of carcasses, and initial findings are communicated back to the submitter within 24 to 48 hours following necropsy. The NWHC can provide management recommendations as well as assist partners with communication and messaging during wildlife mortality events.

Investigation of morbidity and mortality events in wildlife is a collaborative effort, and the NWHC thanks AFWA partners for allowing us to assist you in your management decisions. If you are a new partner interested in exploring the services we provide, or if you currently work with us and would like to know more about other capabilities at the NWHC that may meet your agency needs, please contact us at nwhc-epi@usgs.gov or visit our Diagnostic Services page at www.usgs.gov/nwhc/services. For more information contact Dr. LeAnn White: clwhite@usgs.gov.

AVIAN INFLUENZA Avian influenza continues to circulate worldwide Highly pathogenic avian influenza (HPAI) viruses continue to surprise us each passing year with their amazing capacity for adaptive change. In 2017-2018, over one-hundred HPAI outbreaks occurred in Europe. H5N6 viruses circulated in multiple countries bordering on the North and Baltic Seas, while HPAI H5N8 viruses circulated in the southern regions of Europe in Italy and Bulgaria. All of the European H5N8 outbreaks were in commercial poultry operations, while a mixture of wild bird, backyard flocks and commercial operations were affected by H5N6. While HPAI H5N6 appeared for the first time in the Philippines, it was also found in two provinces in Vietnam, and it caused fewer outbreaks in Korea and Japan than in previous years. H5N8 was widespread in Iran, and to a lesser extent in Iraq. The distribution of H5N8 extended to South Africa, where a number of wild bird species were affected, including the endangered African penguin (Spheniscus demersus). Finally, the HPAI H5N1 virus was found in two provinces each in India and Malaysia, and in four provinces in Cambodia. Additionally, an endogenous HPAI H5N2 continues to circulate in Taiwan. Although the pace of outbreaks worldwide has generally slowed during summer months, nearly 80 HPAI H5 outbreaks have occurred in backyard flocks in multiple states and republics in western Russia since June, including a farm with half a million chickens in the Kostromskaya which was infected with HPAI H5N2. While there is no evidence indicating that HPAI viruses are circulating in wild birds of North America, the USGS National Wildlife Health Center (NWHC) remains vigilant and continues to consistently screen submissions from avian mortality events for presence of avian influenza viruses. For more information contact: Dr. Hon Ip hip@usgs.gov.

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Can low path avian influenza exposure protect against high path avian influenza infection? In the winter of 2014-15, there was an outbreak of highly pathogenic avian influenza virus (HPAI) in wild birds and poultry in the United States. Although HPAI was initially found in wild waterfowl, detections in wild birds decreased despite an increase in poultry cases and extensive surveillance efforts in wild birds*. The NWHC is examining whether the low apparent prevalence of HPAI in wild waterfowl during the outbreak was due to immunity in the waterfowl population conferred through previous exposure to other low pathogenic avian influenza viruses (LPAI). Waterfowl previously exposed to LPAI will be experimentally challenged with the H5N2 HPAI from the recent outbreak. These data will increase our understanding of HPAI virus transmission in wild birds and may be useful for predicting the timing or likelihood of future outbreaks. For more information contact: Dr. Jeff Hall jshall@usgs.gov. *Krauss S, Stallknecht DE, Slemons RD, Bowman AS, Poulson RL, Nolting JM, Knowles JP, Webster RG. 2016. The enigma of the apparent disappearance of Eurasian highly pathogenic H5 clade 2.3.4.4 influenza A viruses in North American waterfowl. Proceedings of the National Academy of Sciences, 113(32),201608853. https://doi.org/10.1073/pnas.1608853113

Adult male mallard, which is often associated with free range poultry, can be reservoirs of avian influenza viruses. (Credit: John Mossesso, USGS. Public domain.)

AMPHIBIAN DISEASES Disentangling drivers of amphibian survival Amphibian populations have continued to decline worldwide due to multiple factors including land use change, contaminants, changes in precipitation, and disease. To examine the combined effect of these drivers, the USGS NWHC and USGS Amphibian Research and Monitoring Initiative have initiated a large-scale study to examine the combined effects of pathogens and environmental factors on adult amphibian survival. Both amphibians and water from around the country are being sampled for Batrachocytrium dendrobatis (Bd) and the exotic salamander fungal pathogen B. salamandrivorans (Bsal). This multi-year study will examine the effects of Bd infection on vital rates of multiple species of amphibians (frogs, toads, salamanders) and examine whether environmental drivers exacerbate or ameliorate the effects of Bd. The goal of the study is to help us formulate regionally based management applications aimed at bolstering amphibian populations. For more information contact: Dr. Dan Grear dgrear@usgs.gov.

An eastern newt is ready for release after being sampled for pathogens and implanted with a passive induced transponder tag for recapture. (Credit: Dan Grear, USGS. Public domain.)

Case definition for severe Perkinsea infection of frogs The USGS National Wildlife Health Center identified severe Perkinsea infection (SPI; a pathogenic protozoa) as the 3rd most common source of tadpole mortality in the NWHC wildlife mortality records (following chytridiomycosis and ranavirosis). To assist with identification of mortality caused by this pathogen, NWHC scientists recently published* a case definition for SPI. Since case definitions include criteria used for disease classification, they are important for consistently counting cases of a disease among jurisdictions, researchers, or laboratories. The publication also summarizes the macroscopic and histologic pathology of over 175 wild frogs with SPI including the frequency and severity of lesions in affected organs. Due to the epidemiological and pathological similarities among SPI and other diseases of tadpoles such as ranavirosis, we stress the importance of complete pathologic evaluation during anuran disease investigations. For more information contact: Dr. Dan Grear dgrear@usgs.gov. *Isidoro-Ayza, M., Grear, D.A., Chambouvet, A. 2018. Pathology and case definition of Severe Perkinsea Infections of frogs. Veterinary Pathology, in press.

Histopathology (H&E stain) showing spherical structures with thick walls that are the Perkinsea organisms spore-like stages (black arrow) and smaller pale structures that are the actively replicating Perkinsea organisms (trophozoite-like; white arrow). These Perkinsea organism stages can replace greater than 60% of tadpole internal organ tissue in a severe infection. (Credit: Marcos Isidoro-Ayza, USGS. Public domain.)

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CHRONIC WASTING DISEASE Can infectious prions be spread in plants? To examine the potential for environmental reservoirs to spread chronic wasting disease (CWD), the USGS National Wildlife Health Center recently investigated whether prions internalized by common crop plants can cause disease in susceptible hosts. Mice were fed the stem and leaf tissues from Arabidopsis thaliana, maize (Zea mays), barley (Hordeum vulgare) and alfalfa (Medicago sativa) grown in culture media containing prions. The study is ongoing but to date, approximately 30% of mice that consumed prion-contaminated crop plants tested positive in brain tissue, as determined by serial protein misfolding cyclic amplification (sPMCA). Testing by sPMCA of spleens has also detected disease-associated prion protein in peripheral tissue outside the central nervous system in some of the mice that consumed prion-contaminated plants. Our results suggest plants represent a currently under-investigated environmental factor that may contribute to CWD transmission and exposure. As CWD continues to increase in both distribution and prevalence, understanding the roles that soil and plants contribute to environmental transmission may be a critical element in managing CWD. For more information contact: Jay Schneider jrschneider@usgs.gov.

Mule deer migration. (Credit: Matt Kauffman, USGS. Public domain.)

Chronic wasting disease surveillance and management...is there a better way? Multiple state, federal, and university partners* have teamed up to forecast CWD growth and spread across the landscape in regions where CWD is endemic or emerging. These forecasts will be used to design surveillance efforts to increase the probability of early detections of CWD. The novel statistical models developed for this project will also be used to examine the effectiveness of historical CWD management activities such as harvest regulation on slowing the growth and spread of CWD. Together, the results of this study will be used to design surveillance systems and targeted management interventions that will most likely assist with detecting and controlling CWD on the landscape. For more information contact: Dr. Dan Walsh dwalsh@usgs.gov. * USGS National Wildlife Center, Kansas State University, University of Wisconsin, Wisconsin Department of Natural Resources, Michigan Department of Natural Resources, Minnesota Department of Natural Resources, Iowa Department of Natural Resources, the US Fish and Wildlife Service, USDA-APHIS Wildlife Services, and University of Wisconsin Steven’s Point

Talking to the public about chronic wasting disease A significant historic and ongoing issue with chronic wasting disease has been delivering accurate, credible scientific and management information to stakeholders. Despite the continuing efforts of natural resource agencies and wildlife health professionals to disseminate accurate information, the abundance of misinformation on CWD has complicated disease management efforts. Editorials, letters to the Editor, and social media posts that express doubt about CWD transmission or management have the ability to alter public perception about CWD facts even when the statements have little scientific merit. The USGS National Wildlife Health Center continues to provide accurate, science-based CWD information in printed and electronic formats (https://pubs.er.usgs.gov/publication/ofr20171138). Our scientists also regularly meet with professional organizations, the media, and assist states with stakeholder meetings to discuss CWD. Most recently we participated in a popular hunter-based podcast, the MeatEater (http://www.themeateater.com/podcasts/ep-070-chronic-wasting-disease/), and a mainstream podcast, The Joe Rogan Experience (http://podcasts.joerogan.net/podcasts/doug-duren-bryan-richards). Although these forums are not the typical venue for many scientists, we encourage natural resource agencies to identify and embrace non-traditional communication forums as they can be used to reach millions of public listeners with accurate information about CWD. For more information contact: Bryan Richards brichards@usgs.gov.

NWHC scientist, Bryan Richards, discusses chronic wasting disease on The Joe Rogan Experience podcast in Los Angeles, CA. (Public domain.)

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HARMFUL ALGAL BLOOMS Are harmful algal blooms harming our wildlife?

Harmful algal blooms (HABs) have the potential to cause harm to fish and wildlife, domestic animals, livestock, and humans through toxin production or ecological disturbances such as oxygen depletion and blockage of sunlight. To investigate the effect of algal toxins on wildlife, the USGS National Wildlife Health Center has examined over 300 dead animals collected during freshwater and marine HAB events since 2000. Varying levels of algal toxins were found in over 100 of these animals. In some cases, the history, clinical signs, and high toxin levels have allowed scientists to attribute mortality to algal toxicosis. Recent events have included Kittlitz’s murrelets (Brachyramphus brevirostris) in Alaska that died after consuming sand lance high in saxitoxin (Shearn-Bochsler et al. 2014), green tree frogs (Hyla cinerea) in Texas with suspected brevetoxicosis in association with a red tide event (Buttke et al. 2018), and little brown bats (Myotis lucifugus carissima) in Utah found dead during a HAB event at a reservoir commonly used for recreation and as a source of municipal drinking water (Isidoro-Ayza et al. In press). In other cases, algal toxins have been detected in wildlife, but their contribution to mortality remains unclear. Part of the reason that these results have been difficult to interpret is that the toxic dose of many algal toxins in wildlife species is unknown and the microscopic lesions, if any in birds, have not been well described. To better understand the effects of saxitoxin, an algal toxin that can occur in both marine and freshwater environments,

on avian species, the NWHC is currently conducting a laboratory exposure trial to determine the lethal dose of saxitoxin in waterfowl followed by an examination of repeated exposure to sub-lethal saxitoxin ingestion. In addition to the exposure trial, a retrospective review of algal toxin detection in the NWHC’s caseload is underway to identify demographic, spatiotemporal, and diagnostic features associated with wildlife exposure to algal toxins. For more information contact: Bob Dusek rdusek@usgs.gov. Literature Cited Buttke DE, Walker A, Huang I, Flewelling L, Lankton J, Ballmann AE, Clapp T, Lindsay J, Zimba PV. 2018. Green Tree Frog (Hyla cinerea) and Ground Squirrel (Xerospermophilus spilosoma) Mortality Attributed to Inland Brevetoxin Transport at Padre Island National Seashore, Texas, USA, 2015. Journal of Wildlife Diseases 54:142- 146. Isidoro-Ayza M, Jones L, Dusek RJ, Lorch JM, Landsberg JH, Wilson P, Graham S. In press. Mortality of Little Brown Bats (Myotis lucifugus carissima) Naturally Exposed to Microcystin-LR. Journal of Wildlife Diseases. Shearn-Bochsler V, Lance EW, Corcoran R, Piatt J, Bodenstein B, Frame E, Lawonn J. 2014. Fatal Paralytic Shellfish Poisoning in Kittlitz's Murrelet (Brachyramphus brevirostris) Nestlings, Alaska, USA. Journal of Wildlife Diseases 50: 933- 937.

Harmful algal bloom in Scofield, Utah. (Credit: Utah Department of Environmental Quality)

Little brown bats found dead during the harmful algal bloom in Scofield, Utah. (Credit: Utah Department of Environmental Quality)

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VACCINE DEVELOPMENT Development of a vaccine for white-nose syndrome

The USGS National Wildlife Health Center is investigating the potential for a virally-vectored vaccine to protect bats against Pseudogymnoascus destructans (Pd), the cause of white-nose syndrome (WNS). This experimental vaccine uses a recombinant raccoon poxvirus vector (which the NWHC successfully used for the sylvatic plague vaccine) and includes two potential antigens, calnexin and serine protease. Initial testing showed promise in reducing morbidity and mortality of bats from WNS. Survival of orally vaccinated bats in a laboratory was much higher and the lesions and impact of WNS were less severe than controls. Work to register WNS vaccines with the USDA Center for Veterinary Biologics (CVB) is in progress to clear the path for eventual field studies. For more information contact: Dr. Tonie Rocke trocke@usgs.gov.

Sylvatic plague vaccine

Plague, caused by Yersinia pestis, is widespread throughout the western US and frequently occurs in wild rodents. All four species of prairie dogs in the US are susceptible to plague, suffering high mortality rates during outbreaks (> 90%). The loss of prairie dogs negatively impacts numerous other species that depend on them for food or shelter, including endangered black-footed ferrets. The USGS National Wildlife Health Center conducted a large, collaborative field test (from 2013-2015 in 7 western states) of the sylvatic plague vaccine (SPV). This study involved state, federal, tribal and non-government agencies organized under the Black-footed Ferret Recovery Implementation Team (BFFRIT), a multi-agency effort led by the US Fish and Wildlife Service. We found that vaccine treatment increased prairie dog abundance and also increased survival at sites with plague outbreaks. Ongoing research is being conducted by partners in USFWS and state agencies to scale-up SPV use and further test it on a landscape scale (sites with 1,000 acres or more) as a management tool for threatened and endangered species, including black-footed ferrets. For more information contact: Dr. Tonie Rocke trocke@usgs.gov.

A gunnison's prairie dog consuming a peanut butter flavored dose of sylvatic plague vaccine. (Credit: Tonie Rocke, USGS. Public domain.)

Oral delivery of vaccine to control rabies in vampire bats (Desmodus rotundus)

Rabies transmitted by vampire bats to cattle or people is a tremendous economic burden in Central and South American countries. Vampire bats are also moving north and in the next decade are expected to disperse into southern Texas. Currently, managers cull vampire bats to reduce their populations by applying a poison to the skin of captured bats and releasing them for transfer to other bats via mutual grooming. Using this effective transfer mechanism as a basis for vaccine delivery, the USGS National Wildlife Health Center is developing an oral vaccine for rabies that can be applied to the skin and transferred to other bats during grooming. An experimental trial will begin soon to confirm efficacy of the vaccine and determine the minimum required dose. The intended goal of this project is to find better ways to manage rabies in bats, reducing risks to humans and domestic animals. This work is being conducted in close collaboration with USDA-APHIS in Mexico.

A vampire bat stares wearily at a researcher who will apply a thick paste with biomarker to the bats back and wings to study how grooming behaviors may help confer immunity to non-captured bats. (Credit: Tonie Rocke, USGS. Public domain.)

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WHITE-NOSE SYNDROME Coordination of white-nose syndrome diagnostics

Coordination of laboratory diagnostics for official reportingis well established within the fields of human and domesticanimal health. By forming a network of laboratories thatstandardizes their work, this collaboration provides certainty of diagnostic results for infectious diseases of consequence to animal welfare, the economy, and society. Although a formal diagnostic network does not currently exist for wildlife pathogens, the need for accurate and comparable results forwildlife have been detailed in previous documents such as the National White-Nose Syndrome Plan*. To that end, the USGS National Wildlife Health Center will soon begindiscussions with laboratorians conducting white-nose syndrome diagnostics to explore opportunities to harmonizelaboratory protocols, interpretation standards, and reportingprocedures for diagnostic test results for Pseudogymnoascus destructans (Pd), the causative agent of white-nose syndrome (WNS). By using the the collective expertise of laboratorians we can increase access to WNS diagnostics while stillpromoting consistency and accuracy of results. Through these efforts we can reduce the amount of uncertainty managersface when considering actions based on diagnostic results.This work is funded by both US Fish Wildlife Service andUSGS. For more information contact: Dr. David Blehertdblehert@usgs.gov and Dr. Katie Richgelskrichgels@usgs.gov. *https://s3.amazonaws.com/org.whitenosesyndrome.assets/prod/b0634260-77d3-11e8-b37b-4f3513704a5e-white-nose_syndrome_national_plan_may_2011.pdf

The wing of a northern long-eared bat is examined for damage at Fort Laramie National Monument, Wyoming. (Credit: Ian Abernethy, Wyoming Natural Diversity Database)

White-nose syndrome continues to spread in North America White-nose syndrome continued to spread in 2018 with detections this past season on bats in two new states (Kansas, South Dakota) and two Canadian provinces (Manitoba, Newfoundland).Pseudogymnoascus destructans, the fungus that causes white-nose syndrome, was also detected on bats dispersing to summer roosts in May 2018 in eastern Wyoming (Goshen County). The Wyoming detections involved big brown bats and a new myotis species, the Western small-footed bat(Myotis ciliolabrum), that had evidence of wing damage. Because these bats were not trapped in association with a hibernaculum, the source(s) of exposure to the fungus is unknown but the WNS detection in South Dakota (Jewel Cave National Monument, Custer County, South Dakota) islocated approximately 200 km away. Documenting population level effects associated with Pd expansion in many western states could bechallenging since the locations of susceptible bat species is less well known. The total number of North America jurisdictions with confirmed cases of the disease now stands at 33 States and seven Canadian provinces. For more information contact: Dr. Anne Ballmann aballmann@usgs.gov.

A little brown bat hanging on a cave wall. Little brown bats are highly susceptible to white-nose syndrome and have experienced wide spread population declines due to the disease. (Credit: Ohio Department of Natural Resources)