Environmental risk factors for infection with Mycobacterium avium complex.

Infection with Mycobacterium avium complex is acquired from the environment, but risk factors for M. avium complex infection and disease are poorly understood. To identify risk factors for infection, the authors performed a 1998-2000 cross-sectional study in western Palm Beach County, Florida, using a population-based random household survey. M. avium complex infection was identified by use of the M. avium sensitin skin test. Of 447 participants, 147 (32.9%) had a positive test reaction, 186 (41.6%) had a negative test reaction, and, for 114 (25.5%), test results were indeterminate. Among the 333 participants with positive or negative M. avium sensitin skin tests, age-adjusted independent predictors of M. avium complex infection in a multivariate model included Black race (odds ratio = 3.8, 95% confidence interval: 2.2, 6.6), birth outside the United States (odds ratio = 2.1, 95% confidence interval: 1.1, 3.9), and more than 6 years' cumulative occupational exposure to soil (odds ratio = 2.7, 95% confidence interval: 1.3, 6.0). Exposure to water, food, or pets was not associated with infection. Results indicate that soil is a reservoir for M. avium complex associated with human infection and that persons whose occupations involve prolonged soil exposure are at increased risk of M. avium complex infection.

Human immunodeficiency virus infection in a rural community in the United States.

In 1986, a population-based survey of human immunodeficiency virus (HIV) infection in a rural Florida community showed that HIV prevalence was 28/877 (3.2%, 95% confidence interval (CI): 2.0, 4.4). In 1998-2000, the authors performed a second population-based survey in this community and a case-control study to determine whether HIV prevalence and risk factors had changed. After 609 addresses had been randomly selected for the survey, 516 (85%) residents were enrolled, and 447 (73%) were tested for HIV. HIV prevalence was 7/447 (1.6%, 95% CI: 0.4, 2.7) in western Palm Beach County and 5/286 (1.7%, 95% CI: 0.2, 3.3) in Belle Glade (p=0.2 in comparison with 1986). Independent predictors of HIV infection in both 1986 and 1998-2000 were having a history of sexually transmitted disease, number of sex partners, and exchanging money or drugs for sex. A history of having sex with men was a risk factor among men in 1986 but not in 1998-2000; residence in specific neighborhoods was a risk factor in 1998-2000 but not in 1986. The authors conclude that heterosexually acquired HIV infection did not spread throughout the community between 1986 and 1998 but persisted at a low level in discrete neighborhoods. Interventions targeting HIV-endemic neighborhoods will be needed to further reduce HIV prevalence in this area.