Doxycycline for malaria prophylaxis in Australian soldiers deployed to United Nations missions in Somalia and Cambodia.

The operational effectiveness of daily doxycycline alone or combined with weekly chloroquine were assessed during deployments of Australian Defence Force personnel to malaria-endemic countries. Doxycycline was given as part of mandated disease prevention measures during United Nations missions to Somalia (900 men for 4 months) and Cambodia (600 men for 12 months over two annual rotations). In Somalia the soldiers were in an area of low endemicity and experienced only three malaria cases (one Plasmodium falciparum, two P. vivax), all occurring after returning to Australia. In Cambodia the level of malaria exposure varied greatly, resulting in eight malaria cases during the entire 2-year mission (two P. falciparum, six P. vivax). Doxycycline was generally well tolerated, with 1.7% (Somalia) and 0.6% (Cambodia) of the men requiring a change of medication to mefloquine due to adverse effects. Doxycycline is an effective chemoprophylactic agent during operational deployments when soldiers truly take it every day.