Routine surveillance of HIV(human immunodeficiency virus) infection an
d AIDS has been established over the past decade in many countries aro
und the world. HIV estimates derived from empirical data are essential
to the assessment of the HIV situation in different parts of the worl
d and trends are used in tracking the development of regional epidemic
s, thereby keeping intervention activities focused on realities. As of
the end of 1995, and following an extensive country-by-country review
of HIV/AIDS data, a cumulative total of 6 million AIDS cases were est
imated to have occurred in adults and children worldwide and currently
20.1 million adults are estimated to be alive and infected with HIV o
r have AIDS, Of the total prevalent HIV infections, the majority remai
n concentrated in eastern, central and southern Africa, but the epidem
ic is evolving with spread of infection from urban to rural areas, as
well as to West and South Africa, India and South-east Asia, and to a
lesser extent - with proportional shifts to heterosexual infections -
in North America, western Europe and Latin America. While the longer-t
erm dimensions of the HIV epidemic al global level cannot be forecast
with confidence, WHO currently projects a cumulative total of close to
40 million HIV infections in men, women and children by the year 2000
. By that time, the male:female ratio of new infections will be close
to I:1. Recent trends indicate that HIV prevalence levels may be stabi
lizing or even decreasing among pregnant women in southern Zaire and p
arts of Uganda, among military recruits aged 21 in Thailand, and in so
me populations of northern Europe and the USA. While these changes may
take place as part of the intrinsic dynamic of the epidemic, there is
some evidence that declines in HIV prevalence are related to declines
in HIV incidence which are, at least partly, due to prevention effort
s. The challenge of surveillance and evaluation methods is now to iden
tify the ingredients of success which may reveal a glimmer of hope.