Surveillance for Highly Pathogenic Avian Influenza Virus in Wild Birds during Outbreaks in Domestic Poultry, Minnesota, 2015.

In 2015, a major outbreak of highly pathogenic avian influenza virus (HPAIV) infection devastated poultry facilities in Minnesota, USA. To understand the potential role of wild birds, we tested 3,139 waterfowl fecal samples and 104 sick and dead birds during March 9-June 4, 2015. HPAIV was isolated from a Cooper's hawk but not from waterfowl fecal samples.

COMPARISON OF CHRONIC WASTING DISEASE DETECTION METHODS AND PROCEDURES: IMPLICATIONS FOR FREE-RANGING WHITE-TAILED DEER (ODOCOILEUS VIRGINIANUS) SURVEILLANCE AND MANAGEMENT.

Throughout North America, chronic wasting disease (CWD) has emerged as perhaps the greatest threat to wild cervid populations, including white-tailed deer (WTD; Odocoileus virginianus). White-tailed deer are the most sought-after big game species across North America with populations of various subspecies in nearly all Canadian provinces, the contiguous US, and Mexico. Documented CWD cases have dramatically increased across the WTD range since the mid-1990s, including in Minnesota, US. CWD surveillance in free-ranging WTD and other cervid populations mainly depends upon immunodetection methods such as immunohistochemistry and enzyme-linked immunosorbent assay (ELISA) on medial retropharyngeal lymph nodes and obex. More recent technologies centered on prion protein amplification methods of detection have shown promise as more sensitive and rapid CWD diagnostic tools. Here, we used blinded samples to test the efficacy of real-time quaking-induced conversion (RT-QuIC) in comparison to ELISA for screening tissues collected in 2019 from WTD in southeastern Minnesota, where CWD has been routinely detected since 2016. Our results support previous findings that RT-QuIC is a more sensitive tool for CWD detection than current antibody-based methods. Additionally, a CWD testing protocol that includes multiple lymphoid tissues (e.g., medial retropharyngeal lymph node, parotid lymph node, and palatine tonsil) per animal can effectively identify a greater number of CWD detections in a WTD population than a single sample type (e.g., medial retropharyngeal lymph nodes). These results show that the variability of CWD pathogenesis, sampling protocol, and testing platform must be considered for the effective detection and management of CWD throughout North America.

Assessing Lead Exposure in Free-Ranging Gray Wolves (Canis lupus) in Minnesota, USA.

The gray wolf (Canis lupus) is both an apex predator and a scavenger in Minnesota, US. Monitoring the health of Minnesota's gray wolf population is an important component of wolf management. Concern regarding whether wolves are being exposed to lead through scavenging viscera of hunter-harvested cervids left on the landscape, led to our study to determine lead-exposure rates. In fall 2012, livers from 147 hunter-harvested wolves (89 females, 58 males) were screened for lead and 20 other elements by inductively coupled plasma-atomic emission spectroscopy. Ten wolves (6.8%) were exposed to lead; only one had high enough exposure (6.14 ppm) to suggest lead toxicosis. Lead exposure varied by time of harvest, with nearly all lead-exposed wolves taken in the late hunting and trapping season (from 24 November 2012 to 31 January 2013), compared with the earlier hunting-only season (3-18 November 2012). Further, eight of 10 lead-exposed wolves were taken from deer-permit areas that harvested >1 deer/km2; only two of 10 were taken where deer harvest was less. This suggests the availability of viscera on the landscape may influence exposure risk of lead to wolves. More research is needed to determine baseline levels for toxic concentrations of lead in gray wolves and to determine clinical signs of lead poisoning in wild canids.

Emergence of the arterial worm Elaeophora schneideri in moose (Alces alces) and tabanid fly vectors in northeastern Minnesota, USA.

BACKGROUND: Moose (Alces alces) are a culturally and economically valued species in Minnesota. However, the moose population has experienced a sudden, marked decline in their range, including extirpation in the northwest and a 66% decline in the last decade in the northeast portions of the state. Although the exact cause of this decline is unclear, parasitic metastrongylid and filarioid nematode infections are known causes of morbidity and mortality in moose across North America. METHODS: To determine if these parasitic nematodes could be contributing to the Minnesota moose population decline, we molecularly examined banked tissues obtained from moose that died of known and unknown causes for the presence of nematode DNA. Extracted brain DNA of 34 individual moose was amplified utilizing primers targeting the 18S rRNA gene and internal transcribed spacer regions of nematodes. RESULTS: DNA sequencing revealed that PCR products obtained from 15 (44.1%) of the moose were 99% identical to Parelaphostrongylus tenuis, a metastrongylid known to cause neurological disease and death. Additionally, brain tissue from 20 (58.8%) individuals yielded sequences that most closely aligned with Elaeophora schneideri, a parasite associated with neurological impairment but previously unreported in Minnesota. Setaria yehi, a common filarioid parasite of deer, was also detected in the brain tissue of 5 (14.7%) moose. Molecular screening of 618 captured tabanid flies from four trapping sites revealed E. schneideri was present (6%) in the Minnesota environment and transmission could occur locally. Prevalence rates among the flies ranged between 0-100% per trapping site, with Chrysops spp. and Hybomitra spp. implicated as the vectors. CONCLUSIONS: Ultimately, these data confirm that P. tenuis is widespread in the Minnesota moose population and raises the question of the significance of E. schneideri as a contributing factor to morbidity and mortality in moose.

Surveillance for Highly Pathogenic Avian Influenza in Wild Turkeys ( Meleagris gallopavo ) of Minnesota, USA during 2015 Outbreaks in Domestic Poultry.

An outbreak of a novel reassortant of highly pathogenic avian influenza A (H5N2) virus (HPAIV) decimated domestic turkeys ( Meleagris gallopavo ) from March through mid-June, 2015 in the state of Minnesota, US. In response, as part of broader surveillance efforts in wild birds, we designed a pilot effort to sample and test hunter-harvested Wild Turkeys ( Meleagris gallopavo ) for HPAIV in Minnesota counties with known infected poultry facilities. We also collected opportunistic samples from dead Wild Turkeys or live Wild Turkeys showing neurologic signs (morbidity and mortality samples) reported by the public or state agency personnel. Cloacal and tracheal samples were collected from each bird and screened for avian influenza virus (AIV) RNA by real-time reverse transcription PCR. From 15 April to 28 May 2015, we sampled 84 hunter-harvested male Wild Turkeys in 11 Minnesota counties. From 7 April 2015 through 11 April 2016, we sampled an additional 23 Wild Turkeys in 17 Minnesota counties. We did not detect type A influenza or HPAIV from any samples, and concluded, at the 95% confidence level, that apparent shedding prevalence in male Wild Turkeys in central Minnesota was between 0% and 2.9% over the sampling period. The susceptibility of wild turkeys to HPAIV is unclear, but regular harvest seasons make this wild gallinaceous bird readily available for future AIV testing.

A SEROSURVEY OF DISEASES OF FREE-RANGING GRAY WOLVES (CANIS LUPUS) IN MINNESOTA, USA.

We tested serum samples from 387 free-ranging wolves ( Canis lupus ) from 2007 to 2013 for exposure to eight canid pathogens to establish baseline data on disease prevalence and spatial distribution in Minnesota's wolf population. We found high exposure to canine adenoviruses 1 and 2 (88% adults, 45% pups), canine parvovirus (82% adults, 24% pups), and Lyme disease (76% adults, 39% pups). Sixty-six percent of adults and 36% of pups exhibited exposure to the protozoan parasite Neospora caninum . Exposure to arboviruses was confirmed, including West Nile virus (37% adults, 18% pups) and eastern equine encephalitis (3% adults). Exposure rates were lower for canine distemper (19% adults, 5% pups) and heartworm (7% adults, 3% pups). Significant spatial trends were observed in wolves exposed to canine parvovirus and Lyme disease. Serologic data do not confirm clinical disease, but better understanding of disease ecology of wolves can provide valuable insight into wildlife population dynamics and improve management of these species.

New roles in hemicellulosic sugar fermentation for the uncultivated Bacteroidetes family BS11.

Ruminants have co-evolved with their gastrointestinal microbial communities that digest plant materials to provide energy for the host. Some arctic and boreal ruminants have already shown to be vulnerable to dietary shifts caused by changing climate, yet we know little about the metabolic capacity of the ruminant microbiome in these animals. Here, we use meta-omics approaches to sample rumen fluid microbial communities from Alaskan moose foraging along a seasonal lignocellulose gradient. Winter diets with increased hemicellulose and lignin strongly enriched for BS11, a Bacteroidetes family lacking cultivated or genomically sampled representatives. We show that BS11 are cosmopolitan host-associated bacteria prevalent in gastrointestinal tracts of ruminants and other mammals. Metagenomic reconstruction yielded the first four BS11 genomes; phylogenetically resolving two genera within this previously taxonomically undefined family. Genome-enabled metabolic analyses uncovered multiple pathways for fermenting hemicellulose monomeric sugars to short-chain fatty acids (SCFA), metabolites vital for ruminant energy. Active hemicellulosic sugar fermentation and SCFA production was validated by shotgun proteomics and rumen metabolites, illuminating the role BS11 have in carbon transformations within the rumen. Our results also highlight the currently unknown metabolic potential residing in the rumen that may be vital for sustaining host energy in response to a changing vegetative environment.

Epidemiology of the lymphatic-dwelling filarioid nematode Rumenfilaria andersoni in free-ranging moose (Alces alces) and other cervids of North America.

BACKGROUND: Moose (Alces alces) are a culturally and economically valued species in Minnesota, where the northeast population has decreased by 60 % since 2006. The cause of the decline is currently unclear; however, parasites, predation, and climate change have all been implicated. Nematode parasites are important pathogens in North American moose, potentially causing severe disease and mortality. Recent spread of Rumenfilaria andersoni, a filarioid nematode of moose, has been documented in Finnish cervids; however, little is known about the epidemiology of this parasite in North America. METHODS: To investigate the prevalence and distribution of R. andersoni, 584 blood samples were collected from live-captured and dead animals and screened microscopically for the presence of microfilariae using a modified Knott's test. Microfilariae were identified based on morphological characteristics. A subset of Knott's-positive animals was subjected to polymerase chain reaction (PCR) with filarioid-specific primers targeting the first internal transcribed spacer region (ITS-1) of the rRNA gene cluster. RESULTS: Rumenfilaria microfilariae were present in 20.5 % of Minnesota moose (n = 352), with slight fluctuations observed over four years. Minnesota white-tailed deer (Odocoileus virginianus) (n = 2) and moose (n = 44) from Alaska, Montana, Washington, Maine, and New Hampshire also harbored R. andersoni, suggesting this parasite occurs widely throughout North American moose herds, and white-tailed deer can serve as a patent host. Sequence analysis of cervid blood (moose, n = 15; white-tailed deer, n = 1) confirmed the identity of R. andersoni and revealed the existence of two distinct clades. Genetic comparisons of R. andersoni isolates from North America and semi-domesticated Finnish reindeer found the two groups to be closely related, supporting previous hypotheses that R. andersoni was recently introduced into Finland by the importation of deer from the United States. CONCLUSIONS: To the best of our knowledge these observations represent the first report of R. andersoni within the contiguous United States and reveal this nematode as a common parasite of North American moose and white-tailed deer. Although the implications of R. andersoni infection on moose health is unclear, increased awareness of this parasite will help prevent unintentional introduction of R. andersoni into naïve populations via the translocation of wild and captive cervids.