By innoculating monkeys with SIV, the simian version of HIV, scientists traced which tissues in the mouth and digestive tract were infected during the first week. Furthermore, they traced which organs and lymph nodes were first infected and uncovered likely routes of infection. The findings are published in today's issue of the journal AIDS.

"This is the first study to assess which tissues had SIV nucleic acid at the earliest times following an oral infection," said Dr. Donald Sodora, senior author of the paper.

Oral transmission of HIV is problematic, especially in developing countries where bottle-feeding infants is not practical. Up to one third of newborns may become infected with the virus that causes AIDS as a result of breastfeeding from an infected mother. There is no evidence that saliva transmits the virus from one person to another. However, oral exposure to the virus through breast milk or semen (during sexual contact) may result in a higher number of infections than originally thought.

The new findings better define early infection in the monkey model, which researchers say they hope will lead to a future vaccine. The animal studies were conducted at the California National Primate Center at the University of California, Davis in collaboration with Dr. Marta Marthas.

"Our goal is to assist in the design of vaccines by providing a more thorough understanding of the early events following oral infection," said Dr. Sodora, assistant professor of internal medicine and microbiology.

In the study, monkeys were infected with SIV administered onto the cheek pouch of the rhesus macaque, likely coming into contact with the oral mucosa and tonsils before being swallowed. Studying the monkeys af
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Contact: Katherine Morales
katherine.morales@utsouthwestern.edu
214-648-3404
UT Southwestern Medical Center
3-Dec-2004