Anopheles claviger and soon after they described the developmental stages of P. falciparum and P. vivax, two of the most important malaria parasite species.
A bitter debate surrounded the discovery that malaria parasites are transmitted by anopheline mosquitoes. Both Grassi and his co-workers, as well as Sir Ronald Ross, a British military doctor working in India, were doing research on the problem at the same time and were influenced by another British scientist, Patrick Manson, who stimulated the working hypothesis that mosquitoes were responsible for malaria transmission. Using avian malaria as a model, Ross was the first to demonstrate the cycle of malaria in mosquitoes. But it was the Italians who definitively documented that only Anopheles mosquitoes can transmit human malaria, and a classic monograph by Grassi in 1900 details the complete development cycle of the parasite in these mosquitoes. In 1902, Ross was awarded the Nobel Prize in Medicine for his work on malaria.
Malaria remains a disease of tremendous concern to the military. Its debilitating effects can often do more damage than the enemy. In a major outbreak during World War I, for example, more than 100,000 British and French troops on the Macedonian front were sidelined. Responding to a 1916 order to attack, an exasperated French general sent a telegram to Paris complaining, “Mon armee est immobilisee dans les hopitaux.” His army had malaria (Wenyon et al., 1921 quoted in Bruce-Chwatt, 1988).
In World War II, both Allied and Axis troops felt the effects of malaria. The U.S. Army alone recorded over 500,000 cases during the war; the Navy and Marine Corps recorded another 90,000 (Ognibene and Barrett, 1982; D. Robinette, Institute of Medicine, personal communication, 1991). “This will be a long war, if for every division I have facing the enemy, I must count on a second division in the hospital with malaria, and a third division convalescing from this debilitating disease,” said General Douglas MacArthur from the Pacific theater (Russell et al., 1946).
Malaria had a major impact on the American war effort in Vietnam, especially at the beginning of the conflict. In late 1965, nearly 10 percent of soldiers had the disease. “During that period, rates for certain units operating in the Ia Drang valley were as high as 600 per 1,000 per year, and at least two maneuver battalions were rendered ineffective by malaria,” General Spurgeon Neel reported in 1973 (Neel, 1973). Over 80,000 cases of malaria were diagnosed in American troops in Vietnam from 1965 to 1971. The overall mortality rate of 1.7 per 1,000 was low, however, because of rapid diagnosis and treatment of cases as they occurred (Canfield, 1972).