DISEASE(S) AND SYMPTOMS

• fever, malaise, headache, lymphadenopathy, anorexia

• fever usually lasts 2 weeks

• meningitis is occasionally reported

DIAGNOSIS

• poor; few laboratories have antigen for immunoflourescence serology by surrogate E. canis antigen

INFECTIOUS AGENT

• Ehrlichia chaffeensis, a rickettsia

• reservoir is unknown

MODE OF TRANSMISSION

• an undetermined tick transmits the agent (possibly the widely distributed species, Amblyomma americanum)

• no evidence of person-to-person transmission

• although other types of Ehrlichia are transmitted to dogs by the brown dog tick, dogs have not been found to be reservoirs of human disease

DISTRIBUTION

• Southern and mid-Atlantic United States

INCUBATION PERIOD

• unknown; possibly 1 to 3 weeks

TREATMENT

• oral antibiotics: tetracycline

PREVENTION AND CONTROL

• avoidance of tick-infested areas; securing of clothing at entry points (ankles, cuffs, etc.); application of tick repellent to outer clothing

FACTORS FACILITATING EMERGENCE

• organism is probably newly recognized

• possible increase in reservoir and vector populations