Risk factors for HIV infection in a rural cohort in Zimbabwe: a pilot study.

OBJECTIVE: To identify demographic, sexual behavioural and cultural risk factors for human immunodeficiency virus (HIV) infection in a rural community in Zimbabwe. DESIGN: Prospective study. SETTING: Rural area in Zimbabwe. SUBJECTS: 207 subjects (81 males, 126 females) mean age 31.6 years (SD 15.3), range 12 to 76 years living in the area. MAIN OUTCOME MEASURES: HIV seropositivity and seroconversion, exposure or no exposure to risk factor. RESULTS: Prevalence of HIV was 7.7% and was associated with being divorced or widowed [Odds ratio (OR) 4.26, 95% confidence interval (CI) 1.17 to 14.97] and past history of sexually transmitted diseases (STDs) [(OR 3.54, 95% CI 1.31 to 9.89)]. Seroconversion rate was 3.6% per year and was associated with history of STD [Relative Risk (RR) 13.22, 95% CI 1.15 to 156.1)] during the follow up period. Individuals over 20 years of age, those reporting one or more sexual partners, those reporting irregular use of condoms and those scarified were at greater risk than their counterparts. Individuals who reported being circumcised were at slightly lesser risk than those who did not report circumcision. CONCLUSION: STDs were major determinants of HIV transmission in the study area. In addition being divorced or widowed was a risk factor for HIV infection. Scarification, tattooing and circumcision require further investigations.

Retrospective study on the criteria for diagnosis of HIV infection in adults in Zimbabwe.

OBJECTIVE: To review the criteria for diagnosis of HIV infection in adults in order to improve upon the Zimbabwe Adult AIDS case definition. DESIGN: A descriptive study which involved the analysis of "Request fo r HIV Antibody Test" forms which had been submitted by clinicians to Masvingo Public Health Laboratory, between June 1990 and December 1992. SETTING: Masvingo Public Health Laboratory, Zimbabwe. SUBJECTS: 627 adult patients. MAIN OUTCOME MEASURES: HIV seroprevalence; specific, sensitivity and positive predictive values of the Adult AIDS case definition. RESULTS: The HIV seroprevalence in 627 adult patients whose forms had been submitted to Masvingo Public Health Laboratory was 79pc. The criterion for the diagnosis of HIV infection had a very high specificity value of 93pc but low sensitivity of 53pc. The positive predictive value of the case definition was very high (97pc). The positive predictive values of individual symptoms were calculated and only weight loss and persistent generalized lymphodenopathy had high values of 99pc and 72pc respectively. CONCLUSIONS: This study has shown that the criterion used in the diagnosis of HIV infection in Zimbabwe is highly specific but relatively insensitive at identifying seropositive patients. This shows the ability of clinicians to identify HIV positive patients irrespective of the stage of the disease (i.e. HIV related symptoms, AIDS related complex or full blown AIDS). There is also a need for constant monitoring of the clinical manifestations of AIDS patients to keep abreast with newer disease manifestations.

PIP: In Zimbabwe, researchers analyzed data on blood samples collected from 627 adult patients at least 14 years old at all hospitals in the 7 districts of Masvingo Province during June 1990-December 1992 to reexamine the criteria for diagnosis of HIV infection in hopes of improving the Zimbabwe Adult AIDS case definition. This case definition is: an illness characterized by at least 2 major signs and 1 minor sign provided serologic tests for HIV are positive (major signs: weight loss 10% of body weight, chronic diarrhea for 1 month, and fever for 1 month; minor signs: cough 1 month, general pruritic dermatitis, recurrent Herpes zoster, oropharyngeal candidates, chronic progressive and disseminated Herpes simplex infection, and generalized lymphadenopathy). 79.1% tested positive for HIV infection. 271 of all adult patients had signs and symptoms that met the criterion for diagnosis of HIV infection. 97.1% of them actually had HIV infection. The specificity for this criterion was 93.9%, but its sensitivity was 53%, suggesting a high ability of clinicians to identify HIV positive patients but low ability to correctly exclude HIV infection. The positive predictive value was higher than that in Uganda (97% vs. 74%). The symptom with the highest positive predictive value and the highest sensitivity value was weight loss greater than 10% of body weight (98.9% vs. 2-71.9% and 74.6% vs. 1.5-57.4%, respectively). Candidiasis and chronic diarrhea had the highest specificity values (86.3% and 85.4%, respectively, vs. 26.4-80.9%). In conclusion, the criterion for diagnosis of HIV infection in Zimbabwe is very specific but rather insensitive at identifying HIV positive patients.