Tumor-Inducing Retroviruses in Wild Turkeys

Background information

Lymphoproliferative disease virus (LPDV) was first detected in North America in 2009 in a wild turkey from Arkansas that had lymphoid tumors. Since its initial diagnosis, multiple surveillance projects across the eastern United States and Canada have detected a varying and often high prevalence (26-83%) of LPDV in healthy and diseased wild turkeys. Despite a low proportion of LPDV-infected wild turkeys developing cancer, many individuals are co-infected with other infectious agents, including bacteria and fowlpox virus. Co-infections with a similar retrovirus, reticuloendotheliosis virus (REV), also is frequently detected.

High LPDV prevalence has been concomitant with population declines in wild turkeys in the midwestern and eastern United States. REV is known to cause immunosuppression, and infected individuals may develop fatal secondary infections. This may also be true for LPDV but because little is known about how LPDV-associated disease develops in wild turkeys, its impact on populations is unclear.

Multiple projects at SCWDS are underway to investigate the pathogenesis of and develop tools to diagnose LPDV. Through experimental infections, we have demonstrated that whole blood, spleen, and bone marrow are reliable diagnostic samples to detect LPDV. Moreover, REV is most frequently detected in bone marrow from turkeys submitted for diagnostic evaluation. Additional studies developing laboratory methods to highlight LDPV and REV in tissues and LDPV-infection impact on wild turkey behavior are underway.

For more information

Manuscripts outlining the experimental infection findings and comparing the LDPV and REV infection prevalence in diagnostic submissions are forthcoming.

Publications of our past work are included below:

Allison, Andrew B., et al. “Avian oncogenesis induced by lymphoproliferative disease virus: a neglected or emerging retroviral pathogen?” Virology 450 (2014): 2-12.

Niedringhaus, Kevin D., et al. “Multicentric round cell neoplasms and their viral associations in wild turkeys (Meleagris gallopavo) in the southeastern United States.” Veterinary pathology 56.6 (2019): 915-920.

Thomas, Jesse M., et al. “Molecular surveillance for lymphoproliferative disease virus in wild turkeys (Meleagris gallopavo) from the eastern United States.” Plos one 10.4 (2015): e0122644.

How you can help

Independent research and projects utilizing diagnostic submissions are ongoing. SCWDS is collaborating with agencies and other researchers to connect LPDV and REV infection with antemortem indicators of health. If your agency is interested in participating, please contact Chloe Goodwin at [email protected].

Canine Distemper Virus Surveillance in North America

Background information

Canine distemper virus (CDV) is a highly infectious Morbillivirus (Family Paramyxoviridae) that causes morbidity and mortality in wild and domestic carnivores, though it has been found in a variety of other mammalian hosts. Species in the families Canidae, Procyonidae, and Mustelidae are among those most susceptible to CDV. CDV is endemic in much of the eastern United States, with epizootic cycles occurring every 3-4 years. During these epizootics, susceptible wildlife species may experience population-level impacts. In the southeast, raccoons serve as the primary reservoir host of CDV, though many carnivore species are highly susceptible. As many of these carnivores are abundant in urban and suburban environments, there is increased risk of CDV spillover into domestic dogs.

Signs of CDV can resemble those of other respiratory, gastrointestinal, and/or neurologic diseases, including rabies virus. Following the introduction of raccoon rabies in the state of North Carolina, CDV testing in the state was hindered, as animals exhibiting neurologic disease were submitted to the North Carolina Department of Public Health (DPH) for rabies screening with no subsequent testing for CDV or other pathogens. In collaboration with the North Carolina Wildlife Resources Commission, SCWDS is conducting a project to analyze prevalence and spatiotemporal patterns of CDV in North Carolina. This includes a retrospective survey of CDV from clinically neurologic animals submitted to DPH for rabies screening, as well as surveillance for CDV in apparently healthy wild carnivores across the state. Additionally, this project aims to assess the effectiveness of a field-friendly sampling method in comparison to more traditional sample collection.

For more information

More information on canine distemper virus can be found on North Carolina Wildlife Resources Commission’s webpage or SCWDS’s recent publication.

How you can help

SCWDS is conducting surveillance for CDV in collaboration with the North Carolina Wildlife Resources Commission. In addition, SCWDS offers diagnostics to its member agencies. If you see any wildlife exhibiting signs resembling canine distemper virus infection, contact your state’s natural resources agency or local animal control. For questions regarding this project, contact Seth Lattner ([email protected]) or Chris Cleveland ([email protected]).

West Nile Virus Surveillance in Mosquito Vector and Animal Hosts

Background information

West Nile virus (WNV) is most commonly spread by the bite of a mosquito. After its introduction to the United States in 1999, WNV is now endemic in much of North America and is the leading cause of mosquito-borne disease in the continental United States. WNV primarily affects birds, causing deaths in over 300 species. It can also infect a wide range of additional hosts including humans, domestic animals including horses, and wildlife such as squirrels, chipmunks, skunks, and bats. Although many WNV infections cause no signs of illness, others can lead to encephalitis, lethargy, paralysis, and/or death. The primary way to prevent WNV transmission is through an integrated approach. This includes eliminating or reducing sources of standing water where mosquitoes lay their eggs, educating the public on mosquito bite prevention, and adult mosquito control.

Prior to the detection of WNV in Georgia in 2001, SCWDS began working with the Georgia Department of Public Health to provide laboratory support for the state’s arbovirus surveillance program. Arboviruses include WNV and other viruses that are spread to people or animals by the bite of an infected arthropod, such as mosquitoes. Subsequently, other states and mosquito control agencies have contracted with SCWDS to provide support for their arbovirus surveillance activities.

For more information

Yearly maps for WNV activity throughout the United States can be found here.

Additional information on WNV in humans can be found here.

More information on WNV in birds can be found here.

Additional information on the activity of several arboviruses in the United States can be found here.

Echinococcus Surveillance in North American Canids

Background information

Echinococcus species tapeworms (Family Taeniidae) are globally distributed parasites that can have profound impacts on agricultural animal health, resulting in economic losses. Furthermore, Echinococcus species are zoonotic, and pose a risk to human health. Adult tapeworms are typically found in the gut of both domestic and wild canid definitive hosts and shed infectious eggs via feces. These embryonated eggs can infect a variety of rodents, even-toed ungulates, and humans.

Historically in the North America, Echinococcus has been found in Canada, midwestern, and northeastern United States. Recently, however, cases of Echinococcus have been documented in the eastern U.S. in coyotes (Canis latrans) and red foxes (Vulpes vulpes). The goals of our research are to screen wild canids for the presence of Echinococcus species in the eastern U.S., determine if Echinococcus species are becoming established in this region, and evaluate the population genetic structure of these parasites in North America. Molecular analyses are used to identify the species of Echinococcus that are found, resulting in additional insight into the intermediate hosts involved in the parasite’s lifecycle.

For more information

Lifecycle of Echinococcus and risk to humans: visit the CDC DPDx page.

How you can help

If you or your state are interested in submitting wild canid gastrointestinal tracts for screening of Echinococcus species please contact [email protected] or [email protected].