The impact of insecticide-treated bednets on malaria and anaemia in pregnancy in Kassena-Nankana district, Ghana: a randomized controlled trial.

The impact of insecticide-treated bednet use on malaria and anaemia in pregnancy was assessed, as a supplementary study, in a major WHO/TDR-supported bednet trial in northern Ghana between July 1994 and April 1995. The study area was divided into 96 clusters of compounds, with 48 clusters being randomly allocated to intervention. All pregnant women were included in the study but the focus was on primigravidae and secundigravidae. 1961 pregnant women were recruited into the study--1033 (52.7%) in the treated bednet group and 928 (47.3%) in the no net group. 1806 (92.1%) had blood taken for malaria microscopy and haemoglobin determination in the third trimester. Pregnancy outcomes were reported for 847 women. The characteristics of women in intervention and control groups were comparable. The odds ratios, with 95% confidence interval (CI), for different study endpoints were, for Plasmodium falciparum parasitaemia--0.89 (0.73, 1.08), for anaemia--0.88 (0.70, 1.09), for low birthweight (LBW)--0.87 (0.63, 1.19), indicating no benefit for treated bednet use. Effective net use by parity varied from 42% in primigravidae to 63% in multigravidae, in spite of free nets and insecticide impregnation. The main reasons for not using a net were warm weather and perceived absence of mosquito biting. Chloroquine use in pregnancy was low and comparable in both groups. Implications of findings for malaria control in pregnancy and further research are discussed.

Verbal autopsies for adult deaths: their development and validation in a multicentre study.

BACKGROUND: Verbal autopsy (VA) has been widely used to ascertain causes of child deaths, but little is known about the usefulness of VA for adult deaths. This paper describes the process used to develop a VA tool for adult deaths and the results of a multicentre validation of this tool. METHODS: A mortality classification was developed by including causes of death that might be arrived at by VAs and causes that are responsive to public health interventions. An algorithm was designed for each cause in the classification, based on classifying symptoms into essential, supportive and differential. A structured questionnaire designed to elicit information on these symptoms was developed in English translated into the local languages. The tool was validated on deaths occurring at hospitals in Tanzania (315 deaths), Ethiopia (249) and Ghana (232). Hospital records of all adult deaths occurring at the study hospitals from June 1993 to April 1995 were collected prospectively. Non-medical interviewers with at least 12 years of formal education conducted VA interviews. Causes of death were diagnosed by a panel of physicians and by a computerized algorithm. The validity of the VA was assessed by comparing the VA diagnoses with hospital diagnoses. RESULTS: Specificity of VAs by physicians fell below 95% only for acute febrile illness (AFI) and TB/AIDS. Sensitivity and positive predictive value (PPV), however, varied widely both across the sites and between causes. Sensitivity was > 75% for tetanus, rabies, direct maternal causes, injuries and TB/AIDS and ranged between 60% and 74% for diarrhoea, acute abdominal conditions and AFI. The PPV was > 75% for tetanus, rabies, hepatitis and injuries and ranged between 60 and 74% for meningitis, AFI, TB/AIDS and direct maternal causes. When the communicable diseases were combined in a single group, the sensitivity was 82%, specificity 78% and PPV 85%. For the group of noncommunicable diseases the corresponding sensitivity, specificity and PPV were 71%, 87% and 67%, respectively. Use of an algorithm resulted in lower sensitivity, specificity and PPV than the VAs by physician. CONCLUSION: VAs by a panel of physicians performed better than an opinion-based algorithm. The validity of VA diagnosis was highest for AFI, direct maternal causes, TB/AIDS, tetanus, rabies and injuries.

The outcome of peripartum cardiac failure in Zaria, Nigeria.

We have studied 227 women who had peripartum cardiac failure (PPCF) in Zaria, Nigeria, since 1969-72. This follow-up and review of survivors in 1993-95 depended chiefly on a Zaria woman (A. Abdullahi) and on her careful reporting. Overall, 31 (13.7%) were completely lost to follow-up, 17 (7.5%) were thought to be alive, and there were data on 179 others (78.8%). Of the 75 known deaths, 55 were cardiovascular--20 due to PPCF, 31 due to cardiac failure unrelated to pregnancy (CF), and four were due to a cerebrovascular accident. PPCF recurred in 13% of 551 subsequent pregnancies. Thirty-two women had a recurrence of PPCF only, and 27 an episode of CF only. Blood pressures rose steadily over the years. An enlarged left ventricle on discharge after the index admission predicted a poor prognosis. In 1993-5, we compared 100 survivors with 100 non-PPCF controls: 96 PPCF women but only 50 control women took extra salt (p = 0.0001). Significantly more PPCF women than controls had a diastolic pressure of 110 mm Hg (p = 0.011). The syndrome is probably provoked in potentially hypertensive women by the traditional practices of eating kanwa, which is rich in Na+, taking additional excess salt and heating the body after delivery. Evidence is presented that PPCF women are potentially hypertensive, and cannot handle the excess ingested sodium which therefore leads to hypervolaemia and thus PPCF.

Schistosomiasis haematobia in Mali: prevalence rate in school-age children as index of endemicity in the community.

In a nationwide survey of schistosomiasis conducted in Mali from 1984 to 1989, 56265 individuals from 323 villages had their urine examined parasitologically using a filtration technique. From a sample of 242 children in 3 villages, aged 7 to 14 years, urine samples were collected and tested for haematuria using reagent strips. Analysis of the age-specific prevalence rates of Schistosoma haematobium infection showed a strong positive correlation between the prevalence rate in the 7-14 year-old age group, and both the overall prevalence (r = 0.90; P < 0.001) and the prevalences at other ages. An index was derived from this relationship using the equation: overall prevalence = -1.14 + 0.74 (prevalence in 7-14 year-olds). The sensitivity and specificity of reagent strip testing for microhaematuria as compared to urine filtration were 73.3% and 83.2% respectively. We conclude that reagent strip testing of urine samples collected from a sample of individuals aged 7-14 years would be sufficient to estimate the overall prevalence of Schistosoma haematobium infection in a Malian community and suggest that this assessment procedure be used at the peripheral level of primary health care to decide on treatment regimes.

The validity of verbal autopsies for assessing the causes of institutional maternal death.

This report presents data from a study carried out in three African countries to assess the validity of verbal autopsies--based on information about symptoms and signs observed antemortem by relatives or associates of deceased individuals--for determining the causes of institutional maternal death. The validity of the verbal autopsy was assessed for each cause of death; and for groups of "direct" and "indirect" maternal causes, by comparing the verbal autopsy diagnoses with the reference diagnoses and calculating their sensitivity, specificity, and positive predictive value. Verbal autopsies were found to be highly specific (98 percent specificity for all causes of maternal death) but not very sensitive (< or = 60 percent sensitivity for all causes except ante/postpartum hemorrhage). Verbal autopsy estimates of cause-specific mortality were comparable to expected values for most of the causes. The study shows that certain direct causes of hospital-based maternal mortality can be determined by means of verbal autopsies with a reasonable level of confidence.

PIP: This study shows that certain direct causes of hospital-based maternal mortality can be validly determined by verbal autopsies. Data were obtained during 1993-95 from a rural district hospital in Kilombero District, Tanzania; a rural teaching hospital in Oromiya Region, Ethiopia; and a rural district hospital in Bawku District, Ghana. Hospital deliveries averaged 1200-1500/year. Maternal deaths averaged 20-30/year. The study population included all adults aged over 15 years dying at ages 15-49 years in the specified hospitals and who lived within 60 km. Data also included hospital records and death certificates. Findings among physicians indicate that direct maternal causes (DMCs), including abortion, had a sensitivity of 82% and a specificity of 93%. For indirect maternal causes (IMCs), the specificity was 97% and the sensitivity was 38%. The positive predictive value (PPV) was 70% for DMCs and 67% for IMCs. Sensitivity was the lowest measure of reliability for all causes. Sensitivity was higher than 60% for all DMCs, with the exception of eclampsia (40%), and lower than 50% for common IMCs. IMCs had a specificity over 98%. The PPV was under 60% for most IMCs and DMCs, except obstructed labor (80%), abortion (64%), and hepatitis (100%). Findings using the algorithm showed lower specificities (93% for DMCs and IMCs). Sensitivity was 60% for DMCs and 68% for IMCs. There was reasonable agreement between physician diagnoses and algorithms. Individual misclassifications of causes were higher in algorithm-based verbal autopsies. False nonmaternal causes were greater among algorithm-based verbal autopsy diagnoses.

The effect of different sensitivity, specificity and cause-specific mortality fractions on the estimation of differences in cause-specific mortality rates in children from studies using verbal autopsies.

BACKGROUND: Verbal autopsies (VA) are increasingly being used in developing countries to determine causes of death, but little attention is generally given to the misclassification effects of the VA. This paper considers the effect of misclassification on the estimation of differences in cause-specific mortality rates between two populations. METHODS: The bias in the percentage difference in cause-specific mortality between two populations has been explored under two different models: i) assuming that mortality from all other causes does not differ between the two populations; ii) allowing for a difference in mortality from all other causes. The bias is described in terms of the sensitivity and specificity of the VA diagnosis and the proportion of mortality due to the cause of interest. Methods for adjustment of sample size and adjusting the estimate of effect are also explored. RESULTS: The results are illustrated for a range of plausible values for these parameters. The bias is more extreme as both sensitivity and specificity fall, and is particularly affected even by a small loss of specificity. The bias also increases as the proportion of all deaths due to the cause of interest decreases, and is affected by the size of the true change in mortality due to the cause of interest relative to the change in mortality from other causes. Calculations from existing data suggest prohibitively large sample sizes may often be required to detect important differences in cause-specific mortality rates in studies using existing VA. CONCLUSIONS: Highly specific VA tools are needed before observed differences in cause-specific mortality can be interpreted. Loss of power due to misclassification may obscure real differences in cause-specific mortality.

HIV-1 disease progression and AIDS-defining disorders in rural Uganda.

BACKGROUND: The majority of people infected with HIV-1 live in Africa, yet little is known about the natural history of the disease in that continent. We studied survival times, disease progression, and AIDS-defining disorders, according to the proposed WHO staging system, in a population-based, rural cohort in Uganda. METHODS: In 1990 we recruited a random sample of people already infected with HIV-1 (as prevalent cases) detected during the initial survey round of a general-population study to form a natural-history cohort. Individuals from the general-population cohort who seroconverted between 1990 and 1995 (incident cases) were also invited to enroll. Participants were seen routinely every 3 months and when they were III. FINDINGS: By the end of 1995, 93 prevalent cases and 86 incident cases had been enrolled. Four patients in the prevalent group were in stage 4 (AIDS) at the initial visit. During the next 5 years, 37 prevalent cases progressed to AIDS. Seven incident cases progressed to AIDS and the cumulative progression to AIDS at 1, 3, and 5 years after seroconversion was 2%, 6%, and 22%, respectively. The cumulative probability of AIDS at 4 years from entering stages 1, 2, and 3 was 11%, 33%, and 58%, respectively. There were 47 deaths among prevalent cases and seven among incident cases during follow-up. The cumulative mortality 4 years after patients entered stages 1, 2, 3, and 4 was 9%, 33%, 56%, and 86%, respectively. The median survival after the onset of AIDS was 9.3 months. INTERPRETATION: Our results are important for the setting of priorities and rationalisation of treatment availability in countries with poor resources. We found that progression rates to AIDS are similar to those in developed countries for homosexual cohorts and greater than for cohorts infected by other modes of transmission. However, we have found that the rates of all-cause mortality are much higher and the progression times to death are shorter than in developed countries.

PIP: The authors studied AIDS-defining disorders, disease progression, and survival times in cohorts of HIV-infected people in a rural region of Uganda. A random sample of people already infected with HIV-1 was recruited in 1990. The subjects had been detected during the initial survey round of a general-population study to form a natural-history cohort. Individuals from the general-population cohort who seroconverted between 1990 and 1995 were also invited to enroll in the study. Participants were seen routinely every 3 months and when they were ill. By the end of 1995, 93 prevalent cases and 86 incident cases had been enrolled. Four patients in the prevalent group were in World Health Organization-defined stage 4 HIV disease, AIDS, at the initial visit. Over the next 5 years, 37 prevalent cases progressed to AIDS. Seven incident cases progressed to AIDS and the cumulative progression to AIDS at 1, 3, and 5 years after seroconversion was 2%, 6%, and 22%, respectively. The cumulative probability of AIDS at 4 years from entering stages 1, 2, and 3 was 11%, 33%, and 58%, respectively. There were 47 deaths among prevalent cases and seven among incident cases during follow-up. The cumulative mortality 4 years after patients entered stages 1, 2, 3, and 4 was 9%, 33%, 56%, and 86%, respectively. The median survival duration after the onset of AIDS was 9.3 months.

An HIV-1 natural history cohort and survival times in rural Uganda.

OBJECTIVE: To describe a population-based rural cohort of HIV-1-seropositive and seronegative individuals established in 1990 in south-west Uganda, and determine survival times in the cohort. DESIGN: Prospective cohort study. METHODS: Participants were recruited from a large population study, and invited to attend a clinic every 3 months. They were seen by clinicians who administered detailed medical questionnaires and undertook a physical examination. RESULTS: By the end of 1995, 390 (79%) of the 491 people asked to enrol in the natural history cohort (NHC) had done so. Ninety-three were prevalent cases of HIV infection detected during the initial survey round of the general population cohort in 1989/1990, 66 were subsequent incident cases, 177 were age-matched HIV-negative controls and 54 were HIV-negative spouses of HIV-positive individuals. Twenty participants seroconverted in the NHC. The age-standardized mortality rates per 1000 person-years for the prevalent, incident, and negative cases were 156.5 [95% confidence interval (CI), 115.8-211.4], 35.0 (95% CI, 16.4 75.0) and 13.5 (95% CI, 7.3-25.1), respectively. The median survival time from enrolment to death for the prevalent cases was 4.5 years (95% CI, 3.5- > 5.2); > 5.4 years from seroconversion for the incident cases; and > 5.2 years from enrolment for the HIV-negative cases. The 5-year cumulative survival for prevalents, incidents and HIV-negative participants was 46%, 83% and 94%, respectively. CONCLUSIONS: We have described an NHC of HIV-positive and HIV-negative participants which is representative of the general population. The NHC was established over 5 years ago; it is continuing and we are maintaining good compliance rates. Survival probabilities in the cohort were lower than most other reported studies.

PIP: To enhance understanding of the natural history of HIV-1 infection among the general population in Africa, a population-based cohort of HIV-prevalent (n = 93) and HIV-incident (n = 66) cases, HIV-negative controls (n = 177), and seronegative partners of HIV-positive cases (n = 54) was recruited in rural southwest Uganda. Between 1990 and 1995, 1353 people-years (PY) of observation were achieved. There were 20 seroconversions during this period. The median duration from enrollment to seroconversion were 25 months for negative controls and 6 months for negative discordants. Of the 64 deaths over the 5-year study period, 54 involved HIV-infected subjects. The age-standardized mortality rates for the prevalent, incident, and negatives per 1000 PY of observation were 156.5 (95% confidence interval [CI], 115.8-211.4), 35.0 (95% CI, 17.4-75.0), and 13.5 (95% CI, 7.3-25.1), respectively. There were no significant differences in the gender-specific mortality rates per 1000 PY in males (48.9) and females (45.7). The median ages at death of prevalent, incident, and negative participants were 33, 53, and 53 years, respectively. The median survival times from enrollment to death were 4.5 years for prevalent cases, over 5.4 years for incident cases, and over 5.2 years for HIV-negative cases. At 5 years, the cumulative survival probabilities for prevalent, incident, and negative cases were 46%, 83%, and 94%, respectively, considerably lower than those reported in other studies. Follow-up of the cohort will continue, and future papers will address the clinical manifestations and other parameters of disease progression.

Clinical and parasitological responses after up to 6.5 years of ivermectin treatment for onchocerciasis.

There are plans to use mass treatment with ivermectin to clear all Africa of the worst ocular and cutaneous effects of onchocerciasis. However, there remains uncertainty about the most suitable treatment regimen and the likely effects of ivermectin on onchocercal skin disease. We have followed 948 subjects for over 6 years in a double-blind, randomized, controlled study of ivermectin for onchocerciasis in a hyperendemic focus in Sierra Leone. Using an intention-to-treat analysis we found a microfilarial prevalence of 16% 6 months after up to 4 annual doses of ivermectin, and 13% prevalence in the group receiving up to 10 doses of ivermectin at 6-monthly intervals. Microfilarial loads were well suppressed in both groups, but repopulation data suggest that adult female worms are still alive and fecund, strongly underlining the need to continue treatment. A clear effect of ivermectin was demonstrated on itching, with about one-third of cases being alleviated. Significant reductions in the prevalence of serious hyperkeratosis, and possibly dyspigmentation (leopard skin), were noted, but not for any other onchocercal skin lesion. Six-monthly and annual treatment regimens with ivermectin were equally effective in terms of dermatological and parasitological impact.

Incidence of hypertension and non-insulin dependent diabetes mellitus and associated risk factors in a rapidly developing Caribbean community: the St James survey, Trinidad.

OBJECTIVE: To compare the incidence rates of hypertension and non-insulin dependent diabetes mellitus in relation to ethnicity and other characteristics in a rapidly developing community. DESIGN: Prospective surveillance of a total community for five years. SUBJECTS: Cohort of 2491 men and women aged 35 to 69 years (79% response), of African, Indian and "other' (mainly Afro-European) descent. RESULTS: During surveillance, secular increases occurred in fasting blood glucose concentrations in both sexes and in body mass index (BMI) in men, with apparent secular reductions in systolic blood pressure in both sexes. Incidence rates of hypertension did not differ significantly with ethnicity, ranging between 33 and 41 per 1000 person-years in men and between 27 and 32 per 1000 person-years in women. In men, the incidence of diabetes (per 1000 person-years) in Indians (24) was significantly higher than in Africans (13) and others (11). In women, the diabetic incidence was similar to that for men in Indians (23) and Africans (14), but in others was twice that in men (21). In both sexes, weight gain was an important risk factor for hypertension, whereas risk of diabetes increased with BMI at baseline. The increased risk of diabetes in Indians among men was independent of baseline BMI and blood glucose. CONCLUSION: Apart from the increased risk of diabetes in Indians, ethnicity had no significant influence on incidence rates of hypertension and diabetes in Trinidad. Secular increases in blood glucose in both sexes and in BMI in men probably contributed to the concurrent increase in mortality from coronary heart disease in this community.

The impact of health education to promote cloth filters on dracunculiasis prevalence in the northern region, Ghana.

This paper describes a health education intervention which was conducted during the 1990 dry season in 3 study villages in the Northern Region of Ghana, to reduce dracunculiasis prevalence in that area by promoting the use of cloth filters for drinking water and avoidance of water contact by sufferers. The impact of the intervention in reducing dracunculiasis prevalence was examined by comparing the period prevalence of infection in 1990 and 1991. The findings demonstrate that the intervention had a measurable but limited impact on dracunculiasis prevalence. Face-to-face health education was successful in persuading 56% of households to buy filters. Ownership of at least one filter for every 10 people in the household was associated with a reduction of at least 20% in the risk of dracunculiasis.

Impact of permethrin impregnated bednets on child mortality in Kassena-Nankana district, Ghana: a randomized controlled trial.

A community-based randomized, controlled trial of permethrin impregnated bednets was carried out in a rural area of northern Ghana, between July 1993 and June 1995, to assess the impact on the mortality of young children in an area of intense transmission of malaria and no tradition of bednet use. The district around Navrongo was divided into 96 geographical areas and in 48 randomly selected areas households were provided with permethrin impregnated bednets which were re-impregnated every 6 months. A longitudinal demographic surveillance system was used to record births, deaths and migrations, to evaluate compliance and to measure child mortality. The use of permethrin impregnated bednets was associated with 17% reduction in all-cause mortality in children aged 6 months to 4 years (RR = 0.83; 95% CI 0.69-1.00; P = 0.05). The reduction in mortality was confined to children aged 2 years of younger, and was greater in July-December, during the wet season and immediately after (RR = 0.79; 95% CI 0.63-1.00), a period when malaria mortality is likely to be increased, than in the dry season (RR = 0.92, 95% CI 0.73-1.14). The ready acceptance of bednets, the high level of compliance in their use and the subsequent impact on all-cause mortality in this study has important implications for programmes to control malaria in sub-Saharan Africa.

A community trial of ivermectin for onchocerciasis in Sierra Leone: compliance and parasitological profiles after three and a half years of intervention.

We have studied the compliance patterns and the long-term effects of repeated ivermectin at various dosing intervals in a randomized controlled trial. The setting for the trial was six neighbouring communities hyperendemic for onchocerciasis in southern Sierra Leone. A total of 335 subjects attended a survey 18 months after the fifth treatment round. Of those randomized to ivermectin, over 85% had received at least three doses. There was no evidence that women of childbearing age were consistently under-treated, despite the criteria for exclusion from treatment. An intention-to-treat analysis showed that a 6-monthly ivermectin treatment regime satisfactorily suppressed microfilarial loads. Microfilarial repopulation was significantly slower over an 18-month period after multiple doses compared to a single dose. Further analysis of microfilarial repopulation suggests that there is a cumulative suppressive effect after at least the first three doses of ivermectin, and that an annual treatment interval is as effective for short-term microfilarial suppression as a 6-monthly interval.

Risk factors for child mortality in northern Ghana: a case-control study.

BACKGROUND: A population-based case-control study was carried out to investigate potential risk factors for post-neonatal and child mortality in northern Ghana were child survival rates are among the lowest in Africa. METHOD: Cases were post-neonatal infant and child deaths identified within a large population under continuous demographic surveillance. For each case, one living control, matched for age, sex and locality, was selected from the demographic database. Mothers of each case and control were interviewed to obtain information on social, enconomic, demographic, environmental and other possible risk factors. Matched analyses of the 317 cases and their controls were performed using discordant pairs analysis and conditional logistic regression. RESULTS: The mortality rate for children aged 6 months to 4 years was estimated as 23.9/1000 children/year. An increased risk of death was observed where the delivery was not performed by a trained person (OR = 1.8, 95% CI: 1.0-3.2), if the preceding birth interval was < 24 months (OR = 2.2, 95% CI: 1.1-3.9), if the father beat the child's mother (OR = 4.3, 95% CI: 1.2-15.6) or if the water source was unprotected (OR = 1.6, 95% CI: 1.0-2.7). No association was found between weaning practices, parental education, or any of the socioeconomic or hygiene variables considered. CONCLUSIONS: Few strong risk factors for mortality were identified, perhaps because living conditions within the study population are relatively homogeneous. While mortality rates may be reduced by targeted interventions, such as increasing deliveries by trained people, more general improvements in the socioeconomic status in the region are essential.

PIP: A population-based case-control study was conducted in the Kassena-Nankana district of the Upper East Region of Ghana to investigate potential risk factors for post-neonatal and child mortality in northern Ghana where child survival rates are among the lowest in Africa. 317 cases of post-neonatal infant and child deaths were matched with controls, with matched analyzes subsequently conducted using discordant pairs analysis and conditional logistic regression. Mothers of each case and control were interviewed to obtain information on social, economic, demographic, environmental, and other possible risk factors. The mortality rate for children aged six months to four years was estimated as 23.9/1000 children/year. An increased risk of death was observed where the delivery was not performed by a trained person, if the preceding birth interval was less than 24 months, if the father beat the child's mother, or if the water source was unprotected. No association was found between weaning practices, parental education, or any of the socioeconomic or hygiene variables considered. The authors note that few strong risk factors for mortality were identified possibly due to the relatively homogeneous living conditions within the study area. While mortality rates can be reduced by targeted interventions, general improvement in the socioeconomic status in the region is needed.

Malaria in a rural area of Sierra Leone. III. Vector ecology and disease transmission.

Studies were undertaken on the role of Anopheles gambiae and An. funestus in the transmission of malaria in four villages in a high-rainfall, forested area in the Bo district of southern Sierra Leone. Anopheles gambiae s.s., identified chromosomally as the Forest form, was the most important vector, with a mean annual sporozoite rate, based on ELISA, of 7.4%. Anopheles funestus, which was found in considerably lower numbers, was mainly a dry season vector, with an annual sporozoite rate of 11.4%. Despite these relatively high sporozoite rates, vector populations were at a low level, with approximate mean densities of only 1.0 An. gambiae and 0.1 An. funestus resting females per house room, and average biting rates of just 1.1 and 0.1 bites/person/night by these two species, respectively. In the rainy season, biting rates peaked at 9.5 An. gambiae bites/person/night and 1.0 An. funestus bites/person/night. Annual sporozoite inoculation rates by An. gambiae and An. funestus were 0.088 and 0.007 infective bites/person/night, respectively. ELISA showed that both species were highly anthropophagic. Exit-trap collections and outdoors searches showed that An. gambiae exhibited a considerable degree of exophily. Light traps inside houses caught nine anopheline species, whereas pyrethrum spray collections in houses caught only An. gambiae, An. funestus and An. hancocki.

Verbal autopsies for adult deaths: issues in their development and validation.

BACKGROUND: The verbal autopsy appears to be an attractive technique for the assessment of causes of adult death in settings where the proportion of people who die while under medical care is low. Verbal autopsies have been used extensively to assess causes of childhood deaths. The existing experience in verbal autopsies for adult deaths is limited mainly to maternal deaths. This paper aims to highlight the critical issues in verbal autopsies to assess causes of adult death which need further research. METHODS: This paper reviews the methods of verbal autopsy used in 35 published studies and discusses issues in the development of verbal autopsies, including mortality classification, design of questionnaires, interviewers, respondents, recall periods, procedures for deriving a diagnosis and the recording of single versus multiple causes of death. It also discusses issues in the validation of verbal autopsies, including the choice of reference diagnosis and the required sample size. RESULTS: The methodological approaches used in verbal autopsy studies have varied widely. Very few studies of the validity of verbal autopsies have been conducted. In these studies, the reported sensitivity and specificity varied widely between different causes of death and between studies. CONCLUSIONS: The information available is inadequate to draw firm conclusions on preferred methodological approaches for verbal autopsies for adult deaths. Before these tools are used more widely for adult deaths, further research is required to compare alternative methods and to evaluate the validity of this tool in a range of settings.

Water sources and other determinants of dracunculiasis in the northern region of Ghana.

This paper describes a study carried out in a rural area of Ghana on the drinking water sources and other determinants of dracunculiasis (guinea worm disease). The results confirm the association between water source choice and the prevalence of the disease. A logistic regression model was used to show the combined effect of several behavioural, biological, and environmental risk factors. The important behavioural factors were related to the head of household, fetching of water, travelling, and farming. Age was found to be an important biological risk factor for dracunculiasis, but the greatest relative risk applied to those who had suffered from guinea worm disease in the previous year. Although males were significantly more infected than females when analysing the raw data, sex did not prove to be a significant risk factor in this model. Village of residence was an important environmental risk factor for dracunculiasis. Factors related to socio-economic status were not associated with the risk of infection. The paper concludes by presenting the policy implications of the study findings.