Typhus, Tick

Denotes a variety of spotted rickettsial fevers, often named by their

• Geographic location (eg, Mediterranean spotted fever, Queensland tick typhus, Oriental spotted fever, African tick bite fever, Siberian tick typhus, North Asian tick typhus)

• Morphology (eg, boutonneuse fever)

Illnesses are caused by various rickettsial organisms (eg, R africae, R australis, R conorii, R japonica, R massiliae, R parkeri, R sibirica, and R 364D)

Dogs and wild animals, usually rodents and even reptiles, may serve as reservoirs

Travel is a risk factor for disease, particularly among elderly ecotourists

Fever, headache, myalgias, and rash

Pathogens usually produce an eschar or black spot (tâche noire); however, spotless boutonneuse fever occurs

Painful lymphadenopathy or lymphangitis may also occur

Rarely, papulovesicular lesions may resemble rickettsialpox

Endothelial injury produces perivascular edema and dermal necrosis

Regional adenopathy, disseminated lesions, kidney disease, splenic rupture, and focal hepatic necrosis are observed

Neurologic manifestations are rare but include

• Encephalitis

• Internuclear ophthalmoplegia

• Coronary involvement

• Hemophagocytic syndrome

Clinical

Serologic tests or polymerase chain reaction (PCR) used for confirmation

Start therapy upon clinical suspicion since delayed therapy is the usual cause of increased morbidity

Oral treatment with doxycycline (100 mg/day twice daily) or chloramphenicol (50–75 mg/kg/day in four divided doses) for 7–10 days is indicated

Caution is advised with use of ciprofloxacin because it

• Is associated with a poor outcome

• Increases the severity of Mediterranean spotted fever

Macrolides are often given to manage acute febrile illness in endemic areas

The combination of erythromycin and rifampin is effective and safe in pregnancy

Prevention entails protective clothing, repellents, and inspection for and removal of ticks