Doxycycline Prophylaxis for Human Scrub Typhus

Abstract

The use of doxycycline, as a prophylactic antibiotic against scrub typhus was investigated in a prospective, randomized, double-blind study. Twenty volunteers were divided into two similar groups. Beginning three days before exposure to Leptotrombidium fletcheri chiggers infected with Rickettsia tsutsugamushi, and continuing for six weeks after exposure, one group received weekly 200-mg oral doses of doxycycline and the other group received a placebo. Nine of 10 doxycycline-treated subjects remained well during prophylaxis but developed antibody to scrub typhus, whereas nine of 10 subjects given the placebo required treatment for scrub typhus. Therefore, the efficacy of the regimen in preventing scrub typhus was 89% (eight cases prevented of nine expected). Ten days after successfully completing prophylaxis, eight of nine subjects reported minor self-limiting symptoms. A single dose of doxycycline was given on day 3 of illness to volunteers who developed scrub typhus. Such therapy was initially effective but was frequently followed by relapse and cannot be recommended.

Rickettsioses and Q fever in travelers (2004–2013)

“…Nine of 10 doxycycline-treated subjects remained healthy during prophylaxis, but developed antibodies to scrub typhus, whereas nine of the 10 subjects given the placebo required treatment for scrub typhus. Therefore, the efficacy of the regimen in preventing scrub typhus was 89% [110].…”

Scrub typhus and rickettsial diseases in international travelers: A review

“…Once-weekly doses of doxycycline (200 mg) can prevent scrub typhus [24,25]. However, it is unknown if daily doxycycline given for malaria prophylaxis would be similarly effective, and doxycycline-resistant strains of O. tsutsugamushi have been described [26,27].…”

Rickettsial Infections in Southeast Asia: Implications for Local Populace and Febrile Returned Travelers

“…95 Doxycycline (100 mg, twice a day for 5-7 days) is recommended for treatment of all SFGR infections. Once a week doses of doxycycline (200 mg) can prevent scrub typhus, 96,97 but there have been no studies on prophylaxis therapy for other rickettsioses. The use of insect repellents, such as N,N-diethyl-3-methylbenzamide (DEET) and permethrinimpregnated clothing and bedding, may also form part of preventive measures against scrub typhus in travelers to disease-endemic areas in Southeast Asia.…”