Significance of herpes zoster in HIV/AIDS in Kweneng district, Botswana

OBJECTIVE: To determine the relevance of herpes zoster eruption or scar relative to other symptoms and signs of HIV/AIDS and to look for a syndromic model that could be used in the diagnosis of HIV infection. DESIGN: Retrospective case-control study on data from the results of HIV request forms in the district from 1st January 1993 to 31st March 1996. HIV request forms bearing ELISA positive results represented the cases. SETTING: All the 55 health facilities and one district hospital in Kweneng district, Botswana. SUBJECTS: Six hundred and forty one valid request forms across all age groups and both sexes were analysed. MAIN OUTCOME MEASURES: Proportion of herpes zoster among cases and controls. Sensitivity and specificity test values for herpes zoster as a screening test. Logistic regression on 11 symptoms and signs found to have a significant relationship to ELISA either on the chi 2 test or on tests for the attributes of an ideal screening test. RESULTS: Herpes zoster ranked sixth as the most common sign associated with a positive ELISA result. The difference in the proportion of herpes zoster among cases and controls was highly significant, (chi 2 = 13.1, OR 3.75, CI =1.7-9.3. p = 0.0003). The following also had a significant relationship; chronic diarrhoea, persistent generalised lymphadenopathy (PGL) and non-healing genital ulcers. In addition, herpes zoster and chronic diarrhoea were highly specific and had high positive predictive values for a positive HIV ELISA positive result in 95.5% cases; chronic diarrhoea, weight loss, herpes zoster, persistent generalised lymphadenopathy and non-healing genital ulcers. CONCLUSION: Herpes zoster is an important predictor of HIV/AIDS in Kweng district (PPV = 90%). Used in the above model, prediction rises up to 95.5%. In the absence of an HIV ELISA test, this model alone could be sufficient for a clinical diagnosis of HIV infection, at least in Kweneng. It is also suggested that the presence or a history of herpes zoster scar or eruption be elevated to the status of a major sign in the World Health Organization (WHO) clinical definition for AIDS surveillance.