Scrub typhus is treated with antibiotics. The drug most commonly used is doxycycline;
but chloramphenicol is an alternative. A combination therapy with doxycycline and
rifampicin should be used in areas where there is poor response to doxycycline
alone (37). Azithromycin or chloramphenicol is useful for treating infection in children
or pregnant women (doxycycline is relatively contraindicated in children). Antibiotic
therapy brings about prompt disappearance of the fever and dramatic clinical
improvement. Rapid defervescence after antibiotic treatment is so characteristic that
it is used as a diagnostic test for O. tsutsugamushi infection (38). These antibiotics are
bacteriostatic and merely slow the multiplication of the organism while the patient
develops a protective immune response. Both animals and humans develop nonsterile
immunity and viable rickettsiae have been recovered from lymph tissue long
after infection (39).
If the antibiotic treatment is discontinued too quickly, especially in patients treated
within the first few days of the fever, relapses may occur. Secondary infections, such
as bacterial pneumonia, should be treated appropriately. No significant morbidity or
mortality occurs in patients who receive appropriate treatment.