When 290 Marines of the 26th Marine Expeditionary Unit and attached units went ashore in Liberia in early September, 80 soon contracted malaria. Of the 157 troops who spent at least one night ashore, 69 became infected. This large outbreak of malaria among Marines was apparently caused by a nearly wholesale failure of the troops to follow protective measures, particular by not taking a once-a-week malaria-preventing drug.
There was a mad scramble by military medical investigators to find out why the infection rates were so high, particularly since there are supposed to be multiple levels of protection (since just one by itself isn't 100% effective). Investigators originally thought there were three possible reasons for the outbreak: The strain of malaria was resistant to the drug taken; the drug wasn't taken correctly; or the drug had gone bad or been manufactured incorrectly.
The findings presented to the House and Senate Armed Services committees showed that only 5 percent of the troops had been regularly taking the recommended drug, (mefloquine), only 12 percent wore uniforms properly treated with the insecticide (permethrin), only 27 percent reported using the time-released insect repellant issued to them and none slept under insecticide-treated mosquito nets.
While the same series of recommendations were given for Liberia as for Afghanistan, Djibouti and Iraq, the risk of contracting malaria in Liberia is about 1,000 times higher than in the Persian Gulf or in Central Asia. The area around Monrovia is a perfect marshy breeding ground for mosquitoes and there is a 50 percent chance that someone taking no protective measures will be infected within a month. Furthermore, all three levels of malaria protection failed, in full or part.
The investigation found that the troops simply weren't taking their Mefloquine (sold under the trade name Lariam), complacency being the main reason the Marines didn't take it - possibly since they knew of the drug's reported side effects: vomiting, dizziness, anxiety, paranoia, sleep disturbances, and abnormal dreams.
The permethrin dipping solution for the uniforms didn't arrive until after the unit left the United States, so they used spray cans to treat the desert-camouflage uniforms the troops wore during their deployment to Iraq and Djibouti. In Liberia, the Marines switched to woodland BDUs and only 12 percent of the troops treated those with the bug juice. The permethrin-treated sleeping nets were not taken ashore, since the mission required that the Marines travel light.
A team of military and civilian epidemiologists, infectious disease physicians and preventive medicine specialists concluded that better education about the risk of malaria is the best way to prevent future outbreaks. They did not think that requiring unit commanders to directly observe people taking their medicine would be practical or necessary. To improve troop protection, military planners noted that there was a need for more choices of drugs.
In 1993, American forces in Somolia encountered malaria. The disease was diagnosed in 131 returning U.S. soldiers and Marines (including 48 who became ill while in Somalia). This raised concern about the need for prompt recognition and treatment in military personnel. Thankfully, the military doctors on board the USS Iwo Jima had completed familiarization training and were able to identify the most extreme cases in Liberia for medevac. - Adam Geibel
Malaria Among U.S. Military Personnel Returning from Somalia, 1993