An infectious disease transmitted by ticks
Tularemia, rabbit or deerfly fever, is a relatively rare bacterial disease transmitted to humans and animals by the bite of ticks. It is much less common that Lyme disease in California and is primarily transmitted by the American dog tick (Dermacentor variablis) and possibly by the Pacific Coast tick (Dermacentor occidentalis). These tick species are common as adults during the spring and summer in San Mateo County. It is a very infectious bacteria and can be transmitted other ways, such as contaminated water, inhalation of airborne bacteria, or handling infected animal carcasess (usually rabbits or rodents).
Symptoms of tularemia are variable, depending on the type of transmission. If transmitted by a tick or deer fly, a person may have an ulcer at the bite site, and swelling of lymph nodes. Sometimes the bacteria enters through the eye, which causes ocular swelling and inflammation. Ingesting contaminated water can cause a sore throat, mouth sores and swollen tonsils. If the bacteria was acquired as an aerosol, symptoms include difficulty breathing, cough and chest pain. All types of transmission are associated with a fever. Tularemia may be cured by early diagnosis and appropriate antibiotic treatment.
Previous human cases of tularemia in San Mateo County have been from ticks on the coast, from a feral cat bite at San Bruno Mountain, and unknown exposures near San Carlos. A confirmed human case occurs only every few years, however, because the disease is treatable by antibiotics, there are likely additional cases that are resolved without disease testing.