which resulted in 4,908 deaths (WHO, 2001f). Africa accounted for 87 percent of the global total. Asia, with a three-fold decrease, still reported 11,246 cases. Central and South America reported 3,101 cases and 40 deaths, these despite reportedly large decreases in Brazil, Ecuador, Guatemala, and Nicaragua. The actual number of cholera cases is believed to be higher in all countries because of alleged underreporting and other surveillance system limitations.

The sixth and most recent global cholera pandemic began in 1961 in Celebes, Indonesia, caused by V. cholera O1, biotype El Tor. It spread rapidly to surrounding countries of eastern Asia and reached Bangladesh in 1963; India in 1964; and the Soviet Union, Iran, and Iraq in 1965–1966 (WHO, 2000d). In 1970, cholera was found in West Africa, where it eventually proliferated and became endemic throughout most of the continent. It then spread to Latin America in 1991, and within the year had reached 11 countries in this region. By the 1990s, cholera had become endemic to Latin America, Africa, and Asia, where periodic countrywide epidemics continued into the twenty-first century.

In 1992, large outbreaks of cholera began in India and Bangledesh that were caused by a previously unrecognized serogroup of Vibrio cholerae, designated O139, synonym Bengal. The epidemic was widespread in the Asiatic continent, with imported cases reported from developed countries. Some regarded this as the eighth cholera pandemic, although the epidemic remained confined to Bangladesh and India. After 1992, V. cholerae O1 was again epidemic in that region (Seas and Gotuzzo, 2000).

Plague

Thanks to modern sanitation and the availability of antibiotics and pesticides, another occurrence of the Black Death5 due to plague appears unlikely. However, isolated cases of plague are still reported in various parts of the world, including the United States, and plague outbreaks are still possible where wild rodent populations are persistently infected with the plague bacillus. Such regions include the western United States and parts of South America, Africa, and Asia. The last great plague epidemic occurred in the early twentieth century in India and resulted in more than 10 million deaths.

Plague is caused by the bacterium Yersinia pestis, which is transmitted to humans by fleas whose primary hosts are rodents; rats, ground squirrels,

5  

Black Death, a devastating pandemic that swept through much of Asia and Europe during the Middle Ages, killed some 20 million people, representing 20 to 25 percent of Western Europe’s total populace.



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