in the 18 years that we have known the acquired immunodeficiency syndrome ( aids ), medical science has made significant advances towards combating the menace. The human immunodeficiency virus ( hiv ) has been isolated and characterised, several drugs have been discovered in record time, vaccine initiatives have been launched with funds that are unprecedented in amount for a single disease. Also, possibly the biggest-ever public health campaign has been launched to prevent its spread.

While efforts to reduce the number of new infections have been successful in the West, there is no let up in hiv infections in developing countries. Data just released by the World Health Organisation ( who ) identifies aids as the fourth biggest killer disease, climbing three notches from it seventh place last year.

According to who , there are over 30 million hiv carriers in the world, with India accounting for about four million; about 2.3 million have already perished due to aids .

Drug therapy, though expensive, is considered to be an important means of controlling the spread of the virus within the body. The 11 anti-retroviral (anti- hiv ) drugs now available