HIV-1 seroprevalence in Zambian patients with acute diarrhea: a community-based study

A package of primary health care services for comprehensive family-centred HIV/AIDS care and treatment programs in low-income settings

Particularly in resource-limited settings, HIV/AIDS is a family concern. Separate services for children and adults may make accessing care more difficult for families than services where family members can be cared for together. Implicit in comprehensive, family-centred approaches to care are the broader notions of longitudinal primary care and linkages to other services, including those based in communities. As highly-active antiretroviral therapy becomes more available, and the direct burden of HIV-associated morbidity diminishes, HIV-infected individuals require primary care that goes beyond exclusive management of HIV and related conditions, including preventive services and the management of common medical issues. The prevention of tuberculosis, diarrhoea, and, in endemic regions, malaria; the addressing of debilitating depression; cervical screening; and the management of chronic cardiovascular disease and its risk factors are all of benefit to patients accessing HIV/AIDS care. Packaging such services is an effective means both of standardizing care within a program and of ensuring patients receives a full roster of available interventions. As family-centred care models develop in resource-limited settings, the availability of evidence-based service packages such as presented here will help program designers prioritize available human and materiel resources toward those interventions that improve patients' global health and well being.

Characteristics and presenting complaints of outpatients with undiagnosed HIV infection: potential utility in selecting subjects for HIV testing

HIV testing of individuals presenting to outpatient medical clinics has generally been based upon a selection system, with testing limited to those having signs or symptoms previously found associated with HIV-1 infection among hospitalized patients. However, little is known about the efficacy of this approach, particularly in Africa. Among patients presenting to a large outpatient infectious disease clinic in Dakar, Senegal, the utility of using specific demographic and behavioral characteristics and individual presenting complaints to identify individuals with previously undiagnosed HIV-1 or HIV-2 infection was examined. Using a simple statistical approach, a composite screening rule was estimated to identify subjects with the highest probability of testing HIV positive, ie, patients who would most benefit from HIV testing. Using the presenting complaint allows identification of 83% of HIV-infected women by testing only 35% of women presenting to the clinic. Similarly, using the presenting complaint and various demographic and behavioral characteristics, it was possible to identify 84% of HIV-infected men by screening 40% of men presenting to the clinic. This study suggests that this method might provide a cost-effective approach that permits limited screening resources to be spent in a way that maximizes individual and societal benefit.

Rapid detection of active and latent tuberculosis infection in HIV-positive individuals by enumeration of Mycobacterium tuberculosis-specific T cells

OBJECTIVES

An accurate test for Mycobacterium tuberculosis infection is urgently needed. The tuberculin skin test (TST) lacks sensitivity, particularly in HIV-infected individuals, and has poor specificity because of antigenic cross-reactivity with Bacillus Calmette-Guérin (BCG) vaccination. ESAT-6 and CFP-10 are antigens expressed in Mycobacterium tuberculosis, but not in Mycobacterium bovis BCG and most environmental mycobacteria. We investigated whether T cells specific for these antigens could serve as accurate markers of M. tuberculosis infection in an area of high tuberculosis and HIV prevalence.

METHODS

Using the rapid ex-vivo enzyme-linked immunospot (ELISPOT) assay for IFN-gamma, we enumerated T cells specific for ESAT-6, CFP-10 and purified protein derivative (PPD) in blood samples from 50 Zambian tuberculosis patients, 75 healthy Zambian adults, and 40 healthy UK residents. TSTs were performed in 49 healthy Zambian adults.

RESULTS

All (100%; n = 11) and 90% (n = 39) of HIV-negative and HIV-positive tuberculosis patients, respectively, had detectable ESAT-6- or CFP-10-specific T cells. The ESAT-6/CFP-10-based ELISPOT assay was positive in 37 out of 54 HIV-negative healthy Zambians, suggesting a 69% prevalence of latent M. tuberculosis infection. Fewer HIV-positive Zambians possessed ESAT-6/CFP-10-specific T cells, but the impact of HIV infection was less on this assay than on the PPD-based ELISPOT or TST.

CONCLUSION

The ESAT-6/CFP-10-based ELISPOT assay detects active tuberculosis in HIV-positive individuals with high sensitivity. It is more specific, and possibly more sensitive, than PPD-based methods of detecting latent M. tuberculosis infection, and may potentially improve the targeting of isoniazid preventative therapy to HIV-positive individuals with latent tuberculosis infection.