Scrub typus -

Ans. is 'a' i.e., R. tsutsugamushi Scmb typhuso Caused by orient! a tsutsugamushio Reservoir of infection is the trombiculid mite.o It is transmitted to man by the bite of infected larval mites.o The nymphal and adult stages of the mite are free living in the soil; they do not feed on vertebrate host. It is the larva (chigger) that feed on vertebrate hosts and picks up the rickettsiae.o The infection is maintained in nature trans-ovarially from one generation of mite to next.o Clinical featursI P. 10-12 days.Chills, fever, headache, malaise.Macular rash appear on 5th day.Punched out ulcer with black eschar at the site of bite.o T/t - Doxycycline is drug of choice for all rickettsial infections.