An estimate of the future size of the tuberculosis problem in sub-Saharan Africa resulting from HIV infection.
The impact of the human immunodeficiency virus (HIV) on tuberculosis is well documented. Its effect in populations with a high proportion of dually infected individuals is likely to be significant. Sub-Saharan Africa is one such region and to better document the effect of HIV infection on tuberculosis there we developed a mathematical model to predict the likely extra numbers of tuberculosis cases due to it. A mathematical model was developed using a variety of scenarios giving a range of risks for the period 1980-2000. The four scenarios included (1) a low rate of 1% risk of tuberculosis infection in year 0 (1980) with 45% tuberculosis infection prevalence, and an HIV prevalence of 2% in 1989; (2) a 2% risk of tuberculosis infection in year 0 with 60% tuberculosis infection prevalence, and a 2% HIV prevalence in 1989; (3) a 2% risk of tuberculosis infection in year 0 with 60% tuberculosis infection prevalence, and a 10% HIV prevalence in 1989; and (4) a 2% risk of tuberculosis infection in year 0 with 60% tuberculosis infection prevalence and a 20% HIV prevalence in 1989. Under scenarios 1 and 2, a 50-60% increase in smear-positive rates in the subpopulation (15-45 years old) is predicted for the year 2000, under scenario 3, smear-positive rates in the subpopulation in the year 2000 are expected to increase four-fold from the 1980 baseline. Under scenario 4, a 10-fold increase in smear-positive rates in 2000 is expected in the subpopulation. Under this scenario, total disease will have increased 12-fold in the subpopulation.(ABSTRACT TRUNCATED AT 250 WORDS)
Schulzer
M
M
Department of Medicine, Vancouver General Hospital, British Columbia, Canada.
Fitzgerald
J M
JM
Enarson
D A
DA
Grzybowski
S
S
D000293:Adolescent; D000328:Adult; D000349:Africa / Q000453:epidemiology; D002648:Child; D015658:HIV Infections / Q000150:complications*; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D008954:Models, Biological; D009894:Opportunistic Infections / Q000150:complications / Q000453:epidemiology*; D015995:Prevalence; D012307:Risk Factors; D014397:Tuberculosis, Pulmonary / Q000150:complications / Q000453:epidemiology*