Introduction: Since effective treatment against HIV has become available, HIV infection surveillance is focussed not only on AIDS cases, but also on new cases of HIV infection. One of the methods used for this task is compilation of case records. We report the results of 18 years of recording information on new diagnoses of HIV (1985-2002) in the area of Salamanca (Spain).
Methods: Our report system is based on active monitoring of results from the microbiology laboratory of the Salamanca Health Area. All patients testing positive in HIV analytical studies and who had not been previously diagnosed as HIV-infected are included in the report system.
Results: A total of 188 579 analytical results were studied. We found 16,772 (9.23%) HIV-positive results, 1984 of which were new HIV infection diagnoses. The incidence for the entire period was 556 cases/100,000 inhabitants. The highest incidence was found in 1992 (62.2 cases/100,000), with a progressive decrease thereafter to 2002 (5.18/100,000). Among the total, 75.3% of patients were men between 20 and 39 years old and more than half (62.2%) were intravenous drug users. Over the period studied, there has been an increase in the age of patients at the time of diagnosis, a trend to increases in the number of cases acquired through heterosexual transmission and a reduction in the number of drug users. During the study period, 312 AIDS cases were declared.
Conclusions: Epidemiological information systems for HIV surveillance are essential to know the features, magnitude and evolution of the epidemic. Creation of a national HIV infection surveillance system to compile the information from smaller regional or local organisms would contribute substantially to our understanding of the epidemiology and evolution of HIV infection.