Peripheral blood smear of a patient with relapse of a fever seven days after remittance is shown. True statement about the etiological agent-: (A) The only reservoir is humans, (B) Vector is hard tick or body louse, (C) It is non-cultivable on cell free media., (D) Soft tick or body louse can transmit the disease
Answer is D. Loosely wound spiral forms on peripheral blood smear shows Borrelia. Diagnosis is relapsing fever. Louse-borne/Epidemic Relapsing fever Tick-borne/endemic relapsing fever Cause-Borrelia recurrentis At least 15 spp- B.duttonii, B.parkeri, B.hermsii B. turicata Tends to occur as epidemic Sporadic cases in endemic areas Vector-body louse Vector-soft tick Inoculation of louse feces into skin Transmitted by bite of soft tick No extra-human reservoir Rodents and other mammals Disease -severe. Disease -milder. CFR-4-40% CFR-1-4% Relapses-1/2 Frequent relapses