Expansion of surveillance case definition for AIDS in resource-poor countries

Genetic susceptibility to herpes simplex virus 1 encephalitis in mice and humans

PURPOSE OF REVIEW

Herpes simplex encephalitis is a rare complication of herpes simplex virus 1 infection that strikes otherwise healthy individuals. Its pathogenesis has long remained elusive. We highlight the investigations dealing with the genetic basis of herpes simplex encephalitis in mice and humans.

RECENT FINDINGS

Mouse models have revealed the impact of various host genes on protective immunity to herpes simplex encephalitis through strain-dependent variability (forward genetics) and via targeted knockouts (reverse genetics). These studies established in particular the crucial role of IFNalpha/beta in immunity to herpes simplex virus 1, paving the way towards the elucidation of the genetic cause of human herpes simplex encephalitis. Two children with rare, specific STAT1 or NEMO mutations displayed a broad impairment of IFNalpha/beta and IFNlambda-mediated immunity and predisposition to several infectious diseases including herpes simplex encephalitis. In contrast, children with UNC93B1 and TLR3 mutations displayed a selective impairment of dsRNA-induced IFNalpha/beta and IFNlambda production and predisposition to isolated herpes simplex encephalitis.

SUMMARY

Herpes simplex encephalitis results from a series of monogenic primary immunodeficiencies that impair the TLR3 and UNC-93B-dependent production of IFNalpha/beta and IFNlambda in the central nervous system, at least in a fraction of children. This is not only crucial for the understanding of immunity to herpes simplex virus 1, but also for the diagnosis and treatment of herpes simplex encephalitis.

Posterior segment manifestations of HIV/AIDS

The ocular posterior segment manifestations of AIDS may be divided into four categories: retinal vasculopathy, unusual malignancies, neuro-ophthalmologic abnormalities, and opportunistic infections. Microvasculopathy is the most common manifestation. Opportunistic infections, particularly cytomegalovirus retinitis and progressive outer retinal necrosis, are the most likely to result in visual loss due to infection or subsequent retinal detachment. Diagnosis and treatment are guided by the particular conditions and immune status of the patient.

Pleural tuberculosis in Harare, Zimbabwe: the relationship between human immunodeficiency virus, CD4 lymphocyte count, granuloma formation and disseminated disease

OBJECTIVE

To elucidate the relationship between HIV, CD4+ count and pleural TB.

METHOD

In a prospective study, 94 patients presenting at two large Harare hospitals with clinically suspected pleural TB were enrolled over a 10-month period. All underwent standardized evaluation, closed pleural aspiration and biopsy. Patients receiving directly observed anti-TB therapy were followed-up.

RESULTS

Pleural TB was diagnosed in 90 individuals (median age 33 years; range 18-65; 64 males); the seroprevalence of HIV was 85%. HIV-positive patients were older than HIV-negative individuals (median age 33 vs 23 years, P = 0.013) and had a significantly lower median CD4+ count (191 vs 1106 x 10(6)/l respectively, P = 0.004). A CD4+ count of <200 x 10(6)/l was associated with a length of illness >30 days (65% vs 37%; P = 0.05), a positive pleural fluid smear (37% vs 0%; P = 0.0006) and a positive pleural biopsy Ziehl-Neelsen stain (35% vs 7%; P = 0.021). However, a relationship between CD4+ count and either pleural granuloma formation or radiological evidence of disseminated disease was not observed.

CONCLUSION

In sub-Saharan Africa, TB pleural effusions have become associated with older age, a chronic onset, and an increased mycobacterial load. These data emphasize the complex relationship between pleural TB, HIV infection and a low CD4+ count.

Impact of the 1994 expanded World Health Organization AIDS case definition on AIDS surveillance in university hospitals and tuberculosis centers in Côte d'Ivoire

OBJECTIVE

To assess the impact of the 1994 expanded World Health Organization (WHO) AIDS case definition on AIDS surveillance in Côte d'Ivoire.

DESIGN

Prospective AIDS case surveillance.

METHODS

From March 1994 through December 1996, passive AIDS case surveillance was conducted at the three university hospitals in Abidjan, and active AIDS case surveillance was conducted at the eight tuberculosis (TB) centers in Côte d'Ivoire. Standardized questionnaires were administered and blood samples for HIV serologic testing were collected from the patients evaluated. The numbers of persons who met the modified 1985 WHO clinical AIDS case definition (Bangui definition) and the 1994 expanded WHO AIDS case definition were determined, and the clinical characteristics of these patients were assessed.

RESULTS

Of 8648 university hospital patients, 3658 (42.3%) met the clinical and/or the expanded case definition: 744 (20.3%) HIV-seropositive persons met only the expanded definition, 44 (1.2%) HIV-seropositive persons met only the clinical definition, 2334 (63.8%) HIV-seropositive persons met both definitions, and 536 (14.7%) HIV-seronegative persons met only the clinical definition. Of 18,661 TB center patients, 9664 (51.8%) met the clinical and/or the expanded definition: 5685 (58.8%) HIV-seropositive persons met only the expanded definition, none of the HIV-seropositive persons met only the clinical definition (by definition), 2625 (27.2%) HIV-seropositive persons met both definitions, and 1354 (14.0%) HIV-seronegative persons met only the clinical definition.

CONCLUSIONS

Because of the inclusion of multiple severe HIV-related illnesses into the expanded definition, the number of reportable AIDS cases in HIV-seropositive patients increased 31.3% in the university hospitals, and 217% in the TB centers. The inclusion of HIV seropositivity as a criterion for the expanded definition also enhanced the specificity of AIDS case reporting, eliminating 536 cases in the university hospitals and 1354 cases in the TB centers in HIV-seronegative patients who had clinical signs of AIDS. The use of the 1994 expanded definition for surveillance purposes should be encouraged in areas of the developing world where HIV serologic testing is available.

AIDS in Africa: what drugs do the carers want or need?

Our objectives were: (1) to discover requirements for treatment of patients with AIDS (PWAs) for health-care workers in eight English-speaking African countries; (2) to establish policies for supply of drugs, and develop a method for determining the contents of parcels (PWA-BOXes) for the relief of PWAs. Fifty-seven questionnaires were sent to non-government medical units treating PWAs, supplied by the charity Inter Care. Of these 37 units replied, two had no known PWAs, three were swamped by refugees; therefore, the total number analysed was 32. Only 24 units had access to HIV testing and the mean number of PWAs per unit was 58. The reported complications of AIDS were: diarrhoea 28 units; tuberculosis 27 units; pneumonia 28 units; sexually transmitted diseases 26; candidiasis 28 units; and herpes zoster 20. Lists of drug requirements were received. We present a protocol for calculation of contents of PWA-BOXes in the hope that this will provide guidelines for other workers in this field.

Evaluation of performance of reused HIVCHEK 1 + 2 test blocks which have shown negative result: a reliable method for rural hospital?

The performance of the reusing of test membranes which have been used previously for negative tests for the detection of antibody to HIV (HIVCHEK 1 + 2 of Ortho Diagnostic Systems, Paris, France) was evaluated under field conditions. The sensitivity and specificity of the reusing strategy compared with a HIV determination obtained by using new HIVCHECK 1 + 2 tests were 89.1% and 100%, respectively. The positive predictive value was 100% and the negative predictive value was 91.5%. The authors conclude that the reduction in sensitivity of the reusing strategy in comparison with the use of new tests makes this strategy ethically unacceptable for the detection of HIV infection in blood donors. On the other hand, the reusing strategy could be very useful for diagnostic purpose and for epidemiological HIV surveillance in resource-poor countries.

Response to treatment, mortality, and CD4 lymphocyte counts in HIV-infected persons with tuberculosis in Abidjan, Côte d'Ivoire

We examined the severity of immune deficiency in patients with HIV-associated tuberculosis in Côte d'Ivoire and assessed its effect on mortality and response to treatment. Consecutive patients attending a tuberculosis treatment centre in Abidjan with smear-positive pulmonary or clinically diagnosed extrapulmonary tuberculosis were tested for HIV-1 and HIV-2 infections and had CD4 lymphocyte counts measured. Patients received standard short-course chemotherapy. Analysis of outcome (restricted to smear-positive tuberculosis patients) was done at 6 months. The 247 HIV-positive patients were significantly more likely than the 312 HIV-negative patients to have CD4 lymphocyte counts of less than 200/microL (43% vs 1%; odds ratio 56.9; [95% CI 19.7-185.3]) and 200-499/microL (39% vs 14%, odds ratio 3.8; [2.5-5.9]). Among HIV-positive patients, median CD4 lymphocyte counts in those with extrapulmonary tuberculosis (198/microL; n = 67) was lower, but not significantly so, than among those with pulmonary tuberculosis (257/microL; n = 180). Among 460 patients with pulmonary tuberculosis, the overall mortality rate was significantly higher in HIV-positive than HIV-negative persons (6% vs 0.4%; relative risk 17.1 [2.2-131.4]), and increased with the severity of immune deficiency; mortality rates in HIV-positive patients with CD4 counts of < 200/microL and 200-499/microL were 10% and 4%, relative risk 27.6 (3.5-220.8); and 11.5 (1.2-109), respectively, compared to HIV-negatives. Among patients completing treatment, cure rates were similar in HIV-positive patients (93%) and HIV-negative patients (92%), and were not related to CD4 counts. Severity of immune deficiency was the major determinant of mortality in HIV-associated tuberculosis. Among people completing treatment, microbiological response was satisfactory irrespective of serological or immune status.

Contribution of tuberculosis to slim disease in Africa

OBJECTIVES

To assess the contribution of tuberculosis to the aetiology of the HIV wasting syndrome (slim) in Africa, a condition usually considered an enteropathy.

METHODS

Clinical examination and representative necropsy study of adult patients positive for HIV.

SETTING

Hospital medical wards in Abidjan, Ivory Coast.

SUBJECTS

Adults positive for HIV.

MAIN OUTCOME MEASURES

CD4 T lymphocyte counts before death, clinical and anthropometric data, and gross and microscopic pathology.

RESULTS

Necropsy was done on 212 HIV positive adults. Tuberculosis was found in 41 of 93 with the clinical HIV wasting syndrome and in 32 of 119 without (odds ratio 2.1, 95% confidence interval 1.2 to 4.0). A significant association existed between the prevalence of tuberculosis at necropsy and the degree of cadaveric wasting (no wasting 25% (15/59); moderate wasting 40% (23/58); skeletal wasting 44% (42/95); P = 0.02). Wasting was also associated with a history of chronic diarrhoea, but no association existed between diarrhoea and tuberculosis. Median CD4 T lymphocyte counts were lowest in wasted patients irrespective of findings at necropsy and in those with chronic diarrhoea (< 60 x 10(6)/l).

CONCLUSION

Wasting and chronic diarrhoea are late stage manifestations of HIV disease in Africa. The importance of tuberculosis as a contributing factor in the pathogenesis of the slim syndrome has been underestimated. In nearly half of patients dying with severe wasting, tuberculosis was the dominant pathological finding.