FOOT-AND-MOUTH DISEASE IN EXPERIMENTALLY INFECTED MULE DEER (ODOCOILEUS HEMIONUS)

Area of Science:

• Veterinary Virology
• Infectious Diseases
• Wildlife Health

Background:

• The 1924-25 California outbreak of foot-and-mouth disease (FMD) in mule deer (Odocoileus hemionus) is the only known wildlife FMD outbreak in the US.
• Limited information exists on FMD pathogenesis and epidemiology in deer.

Purpose of the Study:

• Compare mule deer susceptibility to cattle for FMD virus (FMDV) serotype O.
• Determine FMDV serotype O transmission potential between and within mule deer and cattle.
• Assess FMDV detection in mule deer using conventional laboratory tests.

Main Methods:

• Experimental inoculation of mule deer and cattle with FMDV serotype O.
• Co-housing of infected and susceptible animals to assess transmission.
• Clinical monitoring, necropsy, virus isolation, PCR, and serological testing.

Main Results:

• All mule deer and cattle developed clinical signs and lesions of FMDV infection.
• Mule deer exhibited high prevalence of myocarditis and mortality.
• FMDV was transmitted between mule deer, from cattle to mule deer, and from mule deer to cattle.
• Conventional laboratory tests detected FMDV and antibodies in both species.
• Virus shedding in deer was detected up to 9 days postexposure.

Conclusions:

• Mule deer are highly susceptible to FMDV serotype O, posing a significant risk for disease spread.
• Deer can serve as a reservoir and bridge for FMDV transmission to cattle.
• Effective diagnostic strategies are crucial for early detection in wildlife populations.