East during the Persian Gulf War in 1991 were at risk of contracting malaria, which is endemic in western Saudi Arabia, Yemen, Oman, northern Iraq, and parts of the United Arab Emirates (Gasser et al., 1991). Fortunately, only six cases were diagnosed during the conflict (L. Roberts, Entomology Consultant, Office of the Surgeon General, U.S. Army, personal communication, 1992).
Dengue affects more people worldwide than any other arthropod-borne disease except malaria. More than 2 billion people are at risk, and in some Asian cities virtually every child has been infected by age 12. A small but significant percentage of those infected with dengue virus have severe disease, with hemorrhagic fever and shock.
Epidemiologically, dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) has become an increasingly important international disease. During the first half of the 1980s, 804,000 cases were reported, more than during the previous 25 years. Another 993,000 cases were reported from 1985 through 1989 (Halstead, 1990). Also troubling is the fact that by the early 1990s, Aedes aegypti mosquitoes, the primary vector for dengue virus transmission to humans, had returned in large numbers to most of Central and South America, presenting abundant opportunity for new epidemics.
In 1985, another potential dengue vector, Ae. albopictus, was found to be established in the southern United States; it had been introduced in used tires imported from Japan. This mosquito, commonly known as the Asian tiger mosquito, has spread rapidly across the South and established itself as a permanent resident. Although it has not been found to carry dengue in the United States, it has other troubling features. Eastern equine encephalitis (EEE) virus was recently isolated from Ae. albopictus mosquitoes collected in and around a tire dump in Polk County, Florida, demonstrating the ability of this imported mosquito to carry a native virus (Centers for Disease Control, 1992d). EEE virus is perpetuated in nature in a cycle that includes primarily marsh-nesting and shore birds and the strictly bird-feeding mosquito Culiseta melanura. These Ae. albopictus mosquitoes probably acquired the virus by feeding on infected birds.
Tuberculosis (TB) was the leading cause of death from infectious disease in the United States and Western Europe until the first decade of this century, and it remained the second leading cause from that time until the advent of antimicrobial drugs in the 1950s (Rich, 1944; Waksman, 1964; Dubos and Dubos, 1987). At present, TB kills more people worldwide than