Rickettsiae are unusual bacteria that cause diseases like Rocky Mountain spotted fever. Unlike most bacteria, they can live and multiply only inside host cells.
Each type of rickettsia likes to live in a particular animal and is spread via insect carriers, such as ticks, mites, fleas, or lice. Animals that spread the infection may or may not get sick from it themselves. People and animals usually become infected when bitten by insects that have fed on animals infected with rickettsia.
Signs of infection with rickettsia vary by the animal species affected and the type of rickettsia organism causing the infection. In dogs, possible signs include:
fever
poor appetite
weakness
decreased ability to exercise
lameness
coughing
These infections are seen more often in warm months and usually are not fatal. If the infection becomes long-term, serious damage can occur in the kidneys, lungs, brain, spleen, and bone marrow. Weakness, weight loss, and sometimes death can result.
A history of tick or flea exposure raises suspicion for infection with rickettsia, although exposure is not always obvious. Rickettsiae are hard to detect with standard lab tests. Blood tests and PCR can help confirm the diagnosis when available, Treatment is often started before the results are known, but the key is recognizing that infection with rickettsia could be present.
If treatment begins early, infections with rickettsia usually respond quickly to appropriate antibiotics. Improvement often begins within 1–2 days, and fever generally disappears within 2–3 days. Antibiotics must be given for at least a week, and longer treatment and additional care (including hospitalization) are often needed. If treatment is delayed, recovery is slower and the risk of death increases.
