Current epidemiology of Pneumocystis pneumonia

Abstract

Pneumocystis pneumonia (PCP) has historically been one of the leading causes of disease among persons with AIDS. The introduction of highly active antiretroviral therapy in industrialized nations has brought about dramatic declines in the incidence of AIDS-associated complications, including PCP. In the adult population, the incidence of PCP has significantly decreased, but it remains among the most common AIDS-defining infections. Similar declines have been documented in the pediatric population. In much of the developing world, PCP remains a significant health problem, although its incidence among adults in sub-Saharan Africa has been debated. This review discusses the epidemiology of PCP during the current era of the AIDS epidemic. Although fewer cases of PCP occur in industrialized countries, increasing drug-resistant HIV infections, possible drug-resistant PCP, and the tremendous number of AIDS cases in developing countries make this disease of continued public health importance.

Figure 1

Yearly opportunistic infection rates per 1,000 person-years, CDC Adult and Adolescent Spectrum of Disease Project, 1994–2001. CMV, cytomegalovirus; HAART, highly active antiretroviral therapy; KS, Kaposi's sarcoma; MAC, Mycobacterium avium complex; PCP, Pneumocystis pneumonia. Data are standardized to the population of AIDS cases reported nationally in the same year by age, sex, race, HIV exposure mode, country of origin, and CD4+ lymphocyte count.

Figure 2

Classification of Pneumocystis pneumonia cases from 1999–2001, CDC Adult and Adolescent Spectrum of HIV Disease Project, n = 1,073.

Figure 3

Yearly opportunistic infection rates per 1,000 HIV-infected children, CDC Pediatric Spectrum of Disease Project, 1994–2001. Bacterial, bacterial infections; CMV, cytomegalovirus; HAART, highly active antiretroviral therapy; LIP, lymphocytic interstitial pneumonia; MAC, Mycobacterium avium complex; PCP, Pneumocystis pneumonia. Incidence rates were calculated per 1,000 children at risk each year. All trends were significant at p < 0.05 in chi-square for trend analysis for four age groups (<1 year, 1–5 years, 6–9 years, and >10 years) except for the <1-year-old group for PCP, bacterial, and MAC.