Between 2007 and 2008, Veterinary Public Health
received reports of four dogs suspected of having Rocky Mountain Spotted Fever (RMSF) based on serological testing. A
2008 California Department of Public Health (CDPH) statewide survey found 10 Southern California veterinarians diagnosed cases of RMSF in the
prior year.
RMSF is an acute bacterial disease, caused by
Rickettsia rickettsii, which is transmitted by ticks. Dogs are considered sentinels for human cases of RMSF. However, it is not well-established if the canine cases described above represent true RMSF cases as other spotted fever group rickettsiae can induce cross-reactive antibody responses that may be misinterpreted as a positive RMSF titer.
RMSF in Southern California Ticks
The agent is considered to be rare in local ticks. In 2005, it was detected in one brown dog tick in Riverside County and in 2007 is was found in a Pacific Coast tick in Orange County. (See references below)
Local reporting requirement for suspected RMSF cases
Los Angeles County Veterinary Public Health is asking all veterinarians in LA County to report suspected cases of RMSF in dogs. The Centers for Disease Control and Prevention, and CDPH are assisting Los Angeles County Veterinary Public Health with this program.
References
Wikswo, M.E., Hu, R., Metzger, M.E., and Eremeeva, M.E. (2007) Detection of
Rickettsia rickettsii and
Bartonella henselae in Rhipicephalus sanguineus Ticks from California.
J Med Entomol. 44(1):158-162.
Orange County Vector Control District Press Release. April 2, 2007. Rocky Mountain Spotted Fever Confirmed in County Park.
VETERINARIANS: Report a case of tick-borne disease by using
this form
and email it in to
vet@ph.lacounty.gov or fax to 213-481-2375.
Last updated: July 31, 2020
