A comparative study of gastrointestinal infections in United States soldiers receiving doxycycline or mefloquine for malaria prophylaxis
Arthur, J.D.; Echeverria, P.; Shanks, G.D.; Karwacki, J.; Bodhidatta, L.; Brown, J.E.
American Journal of Tropical Medicine and Hygiene 43(6): 608-613
1990
ISSN/ISBN: 0002-9637 PMID: 2267964 Document Number: 361061
A double blind study of daily doxycycline (100 mg) vs. weekly mefloquine (250 mg) was performed on United States soldiers training in Thailand, to assess the effect of doxycycline malaria prophylaxis on the incidence of gastrointestinal infections. During a 5 week period, 49% (58/119) of soldiers receiving doxycycline and 48% (64/134) of soldiers receiving mefloquine reported an episode of diarrhoea. Infection with bacterial enteric pathogens was identified in 39% (47/119) of soldiers taking doxycycline and 46% (62/134) of soldiers taking mefloquine. Forty-four percent (59/134) of soldiers receiving mefloquine and 36% (43/119) of soldiers receiving doxycycline were infected with enterotoxigenic Escherichia coli (ETEC), while 9% (12/134) of soldiers receiving mefloquine and 4% of soldiers receiving doxycycline were infected with Campylobacter. Side effects from either medication were minimal. After 5 weeks in Thailand, the percentage of non-ETEC strains resistant to >=2 antibiotics increased from 65% (77/119) to 86% (95/111) in soldiers on mefloquine and from 79% (84/106) to 93% (88/95) in soldiers on doxycycline. Doxycycline prophylaxis did not prevent or increase diarrhoeal disease in soldiers deployed to Thailand where ETEC and other bacterial pathogens are often resistant to tetracyclines. The aim of this study was to assess the effect of malaria prophylaxis with either daily doxycycline (100 mg) or weekly mefloquine (250 mg) on the incidence of gastrointestinal infections in US soldiers training in Thailand.In mid-1988, 310 volunteers entered the study and received either mefloquine or doxycycline (plus an identical placebo). During the 5 weeks of the study, no soldier developed malaria. However, 49% of those receiving doxycycline and 48% of those receiving mefloquine developed diarrhoea, and 109 individuals had a stool analysis performed. Enterotoxigenic Escherichia coli was found in 44% of soldiers receiving mefloquine and 36% of soldiers receiving doxycycline. Campylobacter was found in 9% of those on mefloquine and 4% of those on doxycycline. Doxycycline prophylaxis did not prevent or increase diarrhoea diseases in these soldiers.Mary Black.