Spotted fever group
Rickettsia are a group of bacteria that can cause disease in humans, specifically Rocky Mountain spotted fever (RMSF) and Pacific Coast tick fever (PCTF). The bacteria that cause RMSF and PCTF are transmitted by the bite of an infected tick. Symptoms of these diseases usually include a fever and rash ("spots").
In California, the American dog tick (Dermacentor similis*), the Pacific Coast tick (Dermacentor occidentalis), and the brown dog tick (Rhipicephalus sanguineus) can transmit the bacteria that cause RMSF to people and dogs. PCTF is transmitted by the bite of an infected Pacific Coast tick (Dermacentor occidentalis). These ticks can infect a person shortly after they
attachā.
The best way to prevent diseases like RMSF and PCTF that come from ticks is to protect yourself from tick bites: use
tick repelālent when going outside in areas where ticks are common, and check yourself and pets often for ticks while outside and after you return indoors. ā
āā* The American dog tick has been divided into two different species: Dermacentor variabilis primarily occurring east of the Rocky Mountains in North America and
Dermacentor similis occurring west of the Rocky Mountains (Lado et al., 2021). While the predominant species in California has been found to be
D. similis, there may be areas in California where
D. variabilis occurs.ā