Since March 2007, Veterinary Public Health has received reports of four dogs suspected of having Rocky Mountain Spotted Fever (RMSF) based on serological testing. A recent California Department of Public Health (CDPH) statewide survey found 10 Southern California veterinarians diagnosed cases of RMSF in the past 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 three 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.
Tick, flea, and blood testing for dogs is being offered by these state and federal agencies to further evaluate the risk of RMSF and other related rickettsial vector-borne diseases. This testing program is anticipated to last approximately 12 months.
- Please see the separate Canine RMSF Surveillance Program Instruction Sheet for information on how to report cases and submit samples. Free testing might not be available in all cases. Please do not hesitate to call if you have any questions about sample submission or this program. Ask for Dr Emily Beeler or Dr Karen Ehnert (213)-989-7060.
- Please report your suspected cases of RMSF even if you do not plan to submit samples through our office for testing. Fill out and fax in the Canine Rocky Mountain Spotted Fever Reporting Form
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.
RMSF Reporting Veterinarian Instructions
RMSF Case Reporting Form
RMSF CLIENT HANDOUT