During the past decade, HIV infection has exploded in Asian countries. At present, Thailand and India have large populations of HIV-infected individuals, while China and Burma are lagging several years behind but showing virtually identical patterns of infection. In India, seroprevalence among clients at a STD clinic has risen from less then 5 percent in 1988 to 40 percent in 1993. Latin American and the Caribbean . Haiti was one of the original foci of the HIV epidemic, and seroprevalence is estimated at 10 percent in urban areas and 4 percent in rural areas.
Brazil is the most severely affected country in South America.
Viral Variation and Tracking the Spread of the Epidemic HIV isolates can be broken down into different families, or clades, based on degrees of similarity of genetic sequence. Using these relationships as an epidemiological tool, one can determine how the infection spread. All HIV types are found in Africa. Types of HIV prevalent in Europe and North America are closely-related. The HIV found in India is different from that in Thailand.