Foot-and-mouth disease in a limited number of experimentally infected mule deer (Odocoileus hemionus)

Authors: RHYAN, JACK - Animal And Plant Health Inspection Services (APHIS), National Wildlife Center; MCCOLLUM, MATTHEW - Animal And Plant Health Inspection Services (APHIS), National Wildlife Center; GIDLEWSKI, THOMAS - Animal And Plant Health Inspection Services (APHIS), National Wildlife Center; SHALEV, MOSHE - Us Deparment Of Homeland Security; WARD, GORDON - Animal And Plant Health Inspection Service (APHIS); DONAHUE, BRENDA - Animal And Plant Health Inspection Service (APHIS); Arzt, Jonathan; STENFELDT, CAROLINA - Orise Fellow; MOHAMED, FAWZI - Animal And Plant Health Inspection Service (APHIS); NOL, PAULINE - Animal And Plant Health Inspection Services (APHIS), National Wildlife Center; DENG, MING - Animal And Plant Health Inspection Service (APHIS); METWALLY, SAMIA - Animal And Plant Health Inspection Service (APHIS); SALMAN, MO - Colorado State University

Submitted to: Journal of Wildlife Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/30/2019
Publication Date: 1/1/2020
Citation: Rhyan, J., Mccollum, M., Gidlewski, T., Shalev, M., Ward, G., Donahue, B., Arzt, J., Stenfeldt, C., Mohamed, F., Nol, P., Deng, M., Metwally, S., Salman, M. 2020. Foot-and-mouth disease in a limited number of experimentally infected mule deer (Odocoileus hemionus). Journal of Wildlife Diseases. https://doi.org/10.7589/2019-03-059.
DOI: https://doi.org/10.7589/2019-03-059

Interpretive Summary: Foot and mouth disease (FMD), caused by FMD virus (FMDV), is an important livestock disease which remains a major threat to agriculture in the USA. Although it is known that the virus can infect numerous wildlife species, the specific effect in mule deer has not been described in detail. Furthermore, mule deer were known to have been infected during an outbreak of FMD in 1924, but the extent to which they might affect the course of an outbreak today is not known. The goal of this study was to characterize the effects of FMDV on mule deer under controlled laboratory conditions, including testing the ability of the virus to transmit between deer and cattle. We found that mule deer were highly susceptible to the virus and transmission occurred both from cattle to deer and from deer to cattle. Additionally several deer died from a severe form of infection in which the virus infects the heart (myocarditis). This study contributes to understanding the role that wildlife might play in the event of an outbreak of FMD in the USA. The information is critical to planning outbreak responses including animal movement, depopulation, and vaccination.

Technical Abstract: The only known outbreak of foot-and-mouth disease (FMD) in wildlife in the US occurred in mule deer (Odocoileus hemionus) in California in 1924-25. There is little recorded information on the pathogenesis and epidemiology of the disease in deer in that outbreak. In this experimental study, we compared the susceptibility of mule deer to FMD virus (FMDV) serotype O, to that of cattle. We also determined the potential for intra- and interspecies transmission of FMDV serotype O in mule deer and cattle, and assessed conventional laboratory tests in their ability to detect FMDV in mule deer. Two mule deer and one steer were each infected by intraepithelial tongue inoculation with 10,000 bovine tongue infective doses of FMDV, strain O1 Manisa. Inoculated animals were housed with contact animals of both species. When contact-exposed animals developed fever they were placed in rooms with previously unexposed animals. All inoculated and exposed mule deer (n=14) and cattle (n=6) developed clinical disease typical of FMD. Deer had a high prevalence of myocarditis and high mortality. Virus transmission occurred between mule deer, from cattle to mule deer, and from mule deer to cattle. Conventional laboratory tests detected virus and antibodies against nonstructural FMDV proteins in mule deer and cattle. Virus shedding was detected by PCR and virus isolation up to 9 d post-exposure in deer.