Priorities for antiretroviral therapy research in sub-Saharan Africa: a 2002 consensus conference in Zambia

BACKGROUND

A consensus conference was held to discuss priorities for antiretroviral therapy (ART) research in Zambia, one of the world's most heavily HIV-afflicted nations. Zambia, like other resource-limited settings, has increasing access to highly active antiretroviral therapy (HAART) because of declining drug costs, use of government-purchased generic medications, and increased global donations. For sustained delivery of care with HAART in a resource-constrained medical and public health context, operational research is required and clinical trials are desirable. The priority areas for research are most relevant today given the increasing availability of HAART.

METHODS

A conference was held in Lusaka, Zambia, in January 2002 to discuss priority areas for ART research in Zambia, with participants drawn from a broad cross section of Zambian society. State-of-the-art reviews and 6 intensive small group discussions helped to formulate a suggested research agenda.

RESULTS

Conference participants believed that the most urgent research priorities were to assess how therapeutic resources could be applied for the greatest overall benefit and to minimize the impact of nonadherence and viral resistance. Identified research priorities were as follows:Conference participants recommended that HIV-related clinical care and research be integrated within home-based care services and operated within the existing health delivery structures to ensure sustainability, reduce costs, and strengthen the structures.

CONCLUSION

Our consensus was that antiretroviral clinical trials and operational research are essential for Zambia to address the new challenges arising from increasing ART availability. There is global consensus that antiretroviral clinical trials in resource-constrained countries are possible, and the capacity for such trials should be developed further in Africa.

Tuberculosis in children with human immunodeficiency virus infection

For a number of reasons--but especially the human immunodeficiency virus (HIV) epidemic--tuberculosis (TB) is currently increasing in many parts of the world where it threatens the lives of millions of infants and children. The diagnosis of childhood TB, which has always been difficult, is now even more challenging in infants and children co-infected with HIV and Mycobacterium tuberculosis. Both TB and HIV infection require multiple drugs for effective treatment and to prevent the development of resistance by the infecting agents. Drug-drug interactions are therefore common, and knowledge of these is essential in the management of dually infected infants and children. Due to problems with drug toxicity and the need for prolonged treatment, compliance is also a major issue in these children. Chemoprophylaxis against TB in HIV-infected children needs further research, as do the pharmacokinetics of antiretroviral drugs in children. Integrated management of children co-infected with TB and HIV should be encouraged, especially in resource-poor settings.

Study of familial Parkinson's disease in Russia, Uzbekistan, and Zambia

OBJECTIVE

The aims of this study were (A) to determine inheritance patterns of familial Parkinson's disease in three different geographical areas (Russia, Uzbekistan, and Zambia); (B) compare clinical characteristics of familial with sporadic Parkinson's disease; and (C) assess whether there were ethnic differences in clinical manifestations of the disease.

METHODS

Fifty two index cases of familial Parkinson's disease in Moscow, 55 in Tashkent, and 27 in Lusaka were selected on the basis of the typical clinical features of Parkinson's disease with a familial history. The sex ratio, transmission patterns, and segregation ratio were determined by pedigree analysis.

RESULTS

Familial Parkinson's disease was found in all three countries (30 families in Russia, 12 in Uzbekistan, and seven in Zambia), and appeared more common in Russia. Both autosomal dominant and autosomal recessive patterns of inheritance were seen, but autosomal dominance was more common in all countries.

CONCLUSIONS

In all three countries men have a higher risk of developing Parkinson's disease than women and there are ethnic differences in clinical manifestations of the disease. The onset of both familial and sporadic Parkinson's disease in Zambian patients occurs at a younger age and is associated with slow progression and a benign course, and generally responds well to levodopa treatment.

Whole blood versus plasma spots for measurement of HIV-1 viral load in HIV-infected African patients

The increasing availability of antiretroviral drugs to HIV-infected populations in developing countries highlights the need to develop field-friendly practical methods for HIV-1 viral load measurements to monitor the effects of treatment. We compared use of whole-blood spots versus plasma dried on filter paper to quantify HIV-1 viral load in 51 African patients with HIV-1. The mean log10 HIV-1 viral loads were 4.22 for dried plasma spots (DPS) and 4.20 for dried whole-blood spots (DBS). The difference between the pairs of log10 viral load for DPS and DBS were significantly correlated with their mean (Spearman's r=0.31, p=0.03). This correlation between the difference and mean of viral load was no longer evident for values of log10 DPS that were less than 5 (r=0.01, p=0.93). For the 38 paired values with log10DPS of less than 5, the mean difference (log10DPS-log10DBS) was -0.04 (SD 0.29). Dried whole blood stored on filter paper at room temperature shows potential as a field-friendly alternative to plasma for measurement of HIV-1 viral load.

Use of dried whole blood spots to measure CD4+ lymphocyte counts in HIV-1-infected patients

As antiretroviral drugs become widely available in developing countries, practical, field-friendly, and cheap methods of measuring CD4+ lymphocyte counts need to be developed. We tested use of whole blood spots dried on filter paper to measure CD4+ lymphocyte counts. We obtained blood from 42 HIV-1-infected patients from Zambia. We dried blood spots on filter paper and measured CD4+ lymphocyte counts with an established commercial enzyme immunoassay. We compared these measurements with those obtained from matched liquid whole-blood samples analysed with standard flow cytometry. Results of the filter-paper method accorded well with flow cytometry CD4 counts greater than 200 cells/microL (mean difference 13.6 [SD 52.4]). Dried whole blood stored on filter paper could be developed into a field-friendly alternative for CD4+ lymphocyte count measurements.

The relentless spread of tuberculosis in Zambia--trends over the past 37 years (1964-2000)

OBJECTIVE

To review trends in the rates of tuberculosis (TB) case notifications over a 37-year period.

DESIGN

A retrospective study of Ministry of Health records on TB notifications between 1 January 1964 and 31 December 2000.

SETTING

Zambia, sub-Saharan Africa.

METHODS

Retrospective analysis of case-notification data for TB of the Zambia Ministry of Health annual returns.

OUTCOME MEASURES

Annual TB case-notification rates and trends over the past 37 years.

RESULTS

TB case-notification data from 1964 to 2000 show a 12-fold increase over the past two decades, and apparent gains in controlling TB seen in the 1960s and 1970s have been reversed over the past two decades. A stable situation during the period 1964-1984 (case-notification rate remained around 100 per 100,000 population) was followed by an exponential increase since the mid-1980s. The absolute number of new TB cases increased from 8,246 in 1985 (124/100,000) to 38,863 (409/100,000) in 1996 and 52,000 (512/100,000) in 2000. Comparison of case-notification rates over the past 2 decades with neighbouring countries (Zimbabwe, Malawi and Tanzania) show that Zambia has one of the highest case-notification rates in the region.

CONCLUSIONS

Zambia, like many countries in Africa, is in the midst of a serious TB epidemic and there are no signs that it is abating. This increase was most likely due to the impact of the HIV/AIDS epidemic and subsequent breakdown of TB services. Concerted donor-government efforts should invest appropriately in long-term plans for TB control.

Lung diseases at necropsy in African children dying from respiratory illnesses: a descriptive necropsy study

BACKGROUND

Accurate information about specific causes of death in African children dying of respiratory illnesses is scarce, and can only be obtained by autopsy. We undertook a study of children who died from respiratory diseases at University Teaching Hospital, Lusaka, Zambia.

METHODS

137 boys (93 HIV-1-positive, 44 HIV-1-negative], and 127 girls (87 HIV-1-positive, 40 HIV-1-negative) aged between 1 month and younger than 16 years underwent autopsy restricted to the chest cavity. Outcome measures were specific lung diseases, stratified by age and HIV-1 status.

FINDINGS

The presence of multiple diseases was common. Acute pyogenic pneumonia (population-adjusted prevalence 39.1%, 116/264), Pneumocystis carinii pneumonia (27.5%, 58/264), tuberculosis (18.8%, 54/264), and cytomegalovirus infection (CMV, 20.2%, 43/264) were the four most common findings overall. The three most frequent findings in the HIV-1-negative group were acute pyogenic pneumonia (50%), tuberculosis (26%), and interstitial pneumonitis (18%); and in the HIV-1-positive group were acute pyogenic pneumonia (41%), P carinii pneumonia (29%), and CMV (22%). HIV-1-positive children more frequently had P carinii pneumonia (odds ratio 5.28, 95% CI 2.12-15.68, p=0.0001), CMV (7.71, 2.33-40.0, p=0.0002), and shock lung (4.15, 1.20-22.10, p=0.03) than did HIV-1-negative children. 51/58 (88%) cases of P carinii pneumonia were in children younger than 12 months, and five in children aged over 24 months. Tuberculosis was common in all age groups, irrespective of HIV-1 status.

INTERPRETATION

Most children dying from respiratory diseases have preventable or treatable infectious illnesses. The presence of multiple diseases might make diagnosis difficult. WHO recommendations should therefore be updated with mention of HIV-1-positive children. Improved diagnostic tests for bacterial pathogens, tuberculosis, and P carinii pneumonia are urgently needed.

Identification of Pneumocystis carinii DNA in oropharyngeal mouth washes from AIDS children dying of respiratory illnesses

Polymerase chain reaction (PCR) using Pneumocystis carinii-specific primers pAZ 102-H(5'-GTGTACGTTGCAAAGTACTC-3') and pAZ 102-E(5'-GATGGCTGTTTCCAAGCCCA-3') was performed on oropharyngeal washes obtained at autopsy from 22 AIDS children with histologically confirmed P. carinii pneumonia (PCP), and 48 control AIDS children who died from other infections. Fifteen of 22 (68%) PCP samples and none of 48 (0%) control samples had detectable P. carinii DNA (sensitivity 68%; specificity 100%; positive predictive value 100%; negative predictive value 87%). This method requires further validation in clinical practice.

Identification of Pneumocystis carinii DNA by polymerase chain reaction in necropsy lung samples from children dying of respiratory tract illnesses

Polymerase chain reaction for Pneumocystis carinii DNA was performed on necropsy lung samples from children by means of P carinii -specific primers.P carinii DNA was identified in 22 of 22 (100%) samples with histologically proven P carinii pneumonia and 13 of 75 (17%) with non-P carinii pneumonia respiratory illness (sensitivity, 100%; specificity, 83%). The low specificity precludes the use of polymerase chain reaction as an alternative to histopathologic diagnosis.

Clinical presentation, natural history, and cumulative death rates of 230 adults with primary cryptococcal meningitis in Zambian AIDS patients treated under local conditions

SETTING

Inpatient medical wards, Department of Medicine, University Teaching Hospital, Lusaka, Zambia.

OBJECTIVE

To define the natural history, clinical presentation, and management outcome of microbiologically confirmed cryptococcal meningitis in adult AIDS patients treated under local conditions where antifungal and antiretroviral therapies are not routinely available.

DESIGN

A descriptive, longitudinal, observational study.

METHODS

All adult patients admitted to the medical wards of the University Teaching Hospital, Lusaka, Zambia with cerebrospinal fluid culture proved, primary cryptococcal meningitis, during a 12 month period were enrolled into the study. The following details were acquired: clinical features, HIV status, laboratory data, treatment accorded, and survival.

RESULTS

A total of 230 patients with primary cryptococcal meningitis were studied (median age 32 years; range 15-65 years; 112 males, 118 females). Cryptococcal meningitis was the first AIDS defining illness in 210 (91%) patients. One hundred and thirty of the 230 (56%) patients had received treatment with fluconazole monotherapy and 100 (43%) patients received palliative care only without any antifungal therapy. A 100% case fatality rate was observed in both groups at follow up: by seven weeks in the untreated group and at six months in the fluconazole treated group. The cumulative median survival from time of diagnosis was 19 days (range 1-164 days) for the fluconazole treated group and 10 days (range 0-42 days) for the untreated group.

CONCLUSION

Cryptococcal meningitis, under current treatment accorded at the University Teaching Hospital, Lusaka, has a 100% mortality in young Zambian adults with AIDS. The current treatment accorded to Zambian adults with cryptococcal meningitis is inappropriate. An urgent need exists to improve strategies for the clinical management of AIDS patients in poor African countries. The wider ethical and operational issues of making available antifungals to African AIDS patients are discussed.

Helicobacter pylori infection in an urban African population

We have studied 221 adults drawn from an impoverished urban population with high human immunodeficiency virus (HIV) seroprevalence (35%) to determine the prevalence of gastroduodenal pathology and its relationship to serological markers of Helicobacter pylori virulence proteins and other potential environmental and immunological determinants of disease including HIV infection. Eighty-one percent were H. pylori seropositive, and 35% were HIV seropositive. Urban upbringing and low CD4 count were associated with a reduced likelihood of H. pylori seropositivity, as was current Ascaris infection, in keeping with recent evidence from an animal model. One hundred ninety-one adults underwent gastroduodenoscopy, and 14 had gastroduodenal pathology. Mucosal lesions were a major cause of abdominal pain in this population. While the majority of patients with gastroduodenal pathology (12 of 14) were seropositive for H. pylori, none were seropositive for HIV. Smoking was associated with increased risk of macroscopic pathology, and a history of Mycobacterium bovis BCG immunization was associated with reduced risk. Antibodies to H. pylori lipopolysaccharide were associated with pathology. HIV infection was associated with protection against mucosal lesions, suggesting that fully functional CD4 lymphocytes may be required for the genesis of gastroduodenal pathology.

Four-year study of abdominal ultrasound in 900 Central African adults with AIDS referred for diagnostic imaging

BACKGROUND

In the majority of sub-Saharan African countries, the absence of computed tomography facilities makes abdominal ultrasound (US) an alternative diagnostic tool in the clinical investigation of infectious and noninfectious complications of human immunodeficiency virus (HIV)-infected individuals. We studied the abdominal US findings in Central African adult AIDS patients to determine whether the findings were consistent between different population groups and neighboring countries. We performed a longitudinal study of AIDS patients and age- and sex-matched HIV-negative adults referred for abdominal US at two tertiary referral city hospitals: the Gecamines Sendwe Hospital (GSH), Lubumbashi, Congo, and the University Teaching Hospital (UTH), Lusaka, Zambia.

METHODS

Between 1992 and 1996, abdominal US findings in 900 adults (300 Congolese adults from GSH and 600 Zambian adults from UTH; age range = 15-55 years) with a diagnosis of AIDS referred for diagnostic imaging from the inpatient medical wards were recorded; 900 abdominal ultrasound findings from age and sex-matched HIV-negative adults were studied for comparative purposes.

RESULTS

Abdominal US for diagnostic purposes in AIDS patients is requested by clinicians for a range of primary clinical indications: abdominal pain, fever of unknown origin, hepatosplenomegaly, lymphadenopathy, and abnormal liver function tests. Compared with the HIV-individuals, the AIDS group of patients had a significantly higher proportion of splenomegaly (35% vs. 24%; p < or = 0.001), hepatomegaly (35% vs. 22%; p = 0.001), lymphadenopathy (31% vs. 11%; p < or = 0.001), biliary tract abnormalities (25% vs. 12%; p < or = 0.001), gut wall thickening (15% vs. 5%; p < or = 0.001), and ascites (22% vs. 9%; p < or = 0.001). There were no differences in renal tract and pancreatic abnormalities between the AIDS and HIV-groups. There were significantly fewer gallstones in the AIDS group (23% vs. 75%; p < or = 0.001). These patterns of abdominal US abnormalities were consistent across both hospitals.

CONCLUSIONS

Diagnostic imaging by abdominal US is commonly used in the management of a variety of clinical indications in Central Africa. The changes seen on abdominal US in AIDS patients appear uniform across the two countries in Central Africa. These findings may have implications for the radiologist, especially in developing countries, where accurate microbiological or pathologic diagnosis of infectious and noninfectious diseases afflicting the HIV-infected patient is often not possible and US is sometimes relied upon as a "diagnostic" investigation by many physicians. Further studies are required to define patterns of clinical findings, plain films, and pathologic and laboratory correlates with US to develop and refine diagnostic algorithms for clinical use in resource-poor countries.

A study of maternal mortality at the University Teaching Hospital, Lusaka, Zambia: the emergence of tuberculosis as a major non-obstetric cause of maternal death

SETTING

The Department of Obstetrics and Gynaecology, University Teaching Hospital, Lusaka, Zambia.

OBJECTIVES

To ascertain 1) the non-obstetric causes of maternal mortality, 2) the importance of tuberculosis as a cause of maternal deaths, and 3) the trends in the aetiology of non-obstetric causes of maternal deaths during the past decade in the light of the human immunodeficiency virus epidemic.

DESIGN

A 2-year retrospective study of the aetiology of all maternal deaths occurring at the University Teaching Hospital (UTH), Lusaka, Zambia between 1 January 1996 and 31 December 1997. Comparison of these data with available data published between 1974 and 1989.

RESULTS

There were 251 maternal deaths recorded during the study period. Of these, 106 (42%) were due to direct (obstetric) causes and 145 (58%) were due to indirect (non-obstetric) causes. Malaria (30%), tuberculosis (25%) and unspecified chronic respiratory tract infections (22%) accounted for 77% of non-obstetric causes of maternal deaths and 44% of all causes of maternal deaths. The diagnosis of AIDS was closely linked with that of tuberculosis (92% of cases), and unspecified chronic respiratory illnesses (97%), but not with malaria (37%). The maternal mortality ratio for UTH was calculated at 921 per 100,000 live births, a significant increase from the 118 noted in 1982 and 667 in 1989.

CONCLUSIONS

Despite improved obstetric services, the maternal mortality ratios at UTH, Lusaka, have increased eight-fold over the past two decades. This dramatic increase is mainly due to non-obstetric causes of death. Malaria and AIDS-associated tuberculosis and unspecified 'chronic respiratory illnesses' are now major causes of maternal death in Zambia. Greater emphasis is urgently required on early detection, accurate diagnosis, treatment and prevention of malaria and tuberculosis in pregnancy. Further definition of chronic 'unspecified' respiratory illnesses is also required.

Twice weekly tuberculosis preventive therapy in HIV infection in Zambia

BACKGROUND

A randomized double-blind placebo-controlled trial was conducted to estimate the efficacy of preventive therapy for tuberculosis (TB) in HIV-infected adults in Lusaka, Zambia. The main outcome measures were the incidence of TB, mortality and adverse drug reactions.

METHODS

During a 2 year period, 1053 HIV-positive individuals without evidence of clinical TB were randomly assigned to receive 6 months of isoniazid twice a week (H), or 3 months of rifampicin twice a week (R) plus pyrazinamide (Z), or a placebo. Therapy was taken twice a week and was self administered. Subjects presenting with symptoms during the follow-up period were investigated for TB.

RESULTS

The 1053 subjects in the study were followed up for a total of 1631 person-years (median = 1.8 years). Twenty-nine subjects were taken off treatment as a result of adverse drug reactions. A total of 96 cases of TB/probable TB (59 TB and 37 probable TB) were diagnosed during the study period and 185 deaths were reported. One hundred and fifteen subjects (11%) did not return to the study clinic at any time after enrolment. The incidence of TB was lower in those subjects on preventive therapy (H and RZ groups combined) compared with those on placebo (rate ratio = 0.60, 95% CI: 0.36-1.01, P = 0.057), as was the incidence of TB/probable TB (rate ratio = 0.60, 95% CI: 0.40-0.89, P = 0.013). The effect of preventive therapy was greater in those with a tuberculin skin test (TST) of 5 mm or greater, in those with a lymphocyte count of 2x10(9)/l or higher, and in those with haemoglobin of 10 g/dl or higher. There was no difference in mortality rates between the preventive therapy and placebo groups. The effect of preventive therapy declined after the first year of the study so that by 18 months the rates of TB in the treated groups were similar to that in the placebo group.

CONCLUSION

This study has demonstrated that preventive therapy with either twice weekly isoniazid for 6 months or a combination of rifampicin and pyrazinamide for 3 months reduced the incidence of TB in HIV-infected persons in Zambia. No effect was observed on mortality. The effect was greatest in persons who had a positive TST or a lymphocyte count of 2x10(9)/l or greater, indicating that preventive therapy may be more effective in people with less advanced immunosuppression. The limited duration of the protective effect reported in this study raises the question of the need for lifelong preventive therapy or re-prophylaxis.