Infectious Complications

How can epidemiology assist in guiding interventions for the acquired immunodeficiency syndrome/human immunodeficiency virus?

In a single decade, the pandemic of human immunodeficiency virus (HIV) infection has become an international health, social, and economic emergency. Early and effective intervention is urgently needed for both prevention of HIV infection and for the amelioration of clinical disease. Results of therapeutic trials have suggested expanding the population for which chemotherapy is indicated. In this paper, we first review the findings from selected recent drug trials, using zidovudine and pentamidine as examples. We then discuss six issues that we believe to be crucial for future epidemiologic research in the service of vaccine and drug development: 1. To identify which complications of HIV infection most urgently require development of new therapies, we must characterize the frequency and severity of specific medical events (outcomes) in persons taking a variety of treatments. 2. Currently, acquired immunodeficiency syndrome (AIDS) therapeutic trials gauge the effectiveness of new therapies by their impact on such clinical parameters as the time to development of AIDS or death. These approaches take too long to provide information. We urgently need to identify surrogate markers of clinical outcome that will be useful in the early assessment of treatment efficacy. 3. Progress in vaccine development is being retarded because we do not have enough data from natural history studies on host immunologic responses to suggest that a given response is protective. We therefore need to identify natural correlates of immunity, which can help set priorities in vaccine development. 4. Discovery that a therapy works in the setting of a clinical trial is only a first step in intervention. We must also assess the impact of new therapies on the health of the public, evaluating access to health care, compliance, and other barriers to treatment. 5. Clinical trials are usually associated with the effort to prevent disease in infected persons. However, other trials are needed to assess efforts to interrupt viral transmission through use of condoms, use of virucides, and treatment of sexually transmitted diseases, and by effecting specific behavioral changes. 6. Traditional methods of conducting clinical therapeutic research may not be adequate to address urgent questions in the AIDS/HIV epidemic. We must develop innovative clinical research methods, including better use of data from observational studies, to infer what we can about the effect of treatment on the clinical course.

HIV seropositivity and tuberculosis in a rural Malawi hospital

This study was undertaken to determine the extent to which human immunodeficiency virus (HIV) infection has increased hospital admissions for tuberculosis (TB) in a rural population of southern Malawi. The notes and chest X-rays of TB patients admitted to Malamulo hospital in 1983 and 1984, before the recognition of acquired immune deficiency syndrome (AIDS) in Malawi, were compared with those of patients admitted in 1987 and 1988. We found a 160% increase in TB admissions between the 2 periods. Extrapulmonary TB, especially pleural TB, was much commoner in 1987-1988 and occurred in a younger age group. HIV seroreactivity was measured in a third group of 152 tuberculosis patients admitted during 1988-1989. HIV seropositivity was found in 52% of all tuberculosis admissions and in 75% of those with extrapulmonary disease. There was no difference in clinical response to TB therapy between the HIV seropositive patients and those who were seronegative. Extrapulmonary TB should be considered in all HIV seropositive patients, especially in areas where the prevalence of TB is high. Health personnel involved in TB programmes where HIV and TB infections are prevalent should plan for a large increase in the TB case load secondary to the HIV pandemic.

Enterovesical fistula in a patient with cryptosporidiosis and AIDS. CT demonstration

A case of an enterovesical fistula demonstrated by computed tomography (CT) scan in an AIDS patient with cryptosporidiosis is reported. Other studies including barium enema and endoscopy were unsuccessful in detection of the fistula. The value of CT in both the AIDS patient and the patient with suspected enterovesical fistula is reviewed.