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OBJECTIVE: To determine trends in the causes of death in a West African town. Mortality caused by infectious diseases is reported to be declining while degenerative and man-made mortality factors are increasingly significant. Most mortality analyses for sub-Saharan Africa have involved extrapolation and have not been derived from community-based data. METHODS: Historical data on causes of death coded by physicians were analysed for the urban population of Banjul for the period 1942-97. As the calculation of rates is not possible in the absence of a reliable population denominator, age-standardized proportional mortality ratios (PMRs) for men and women by major groups of causes of death were calculated, using the 1942-49 data for reference purposes. FINDINGS: Most deaths were attributable to communicable diseases. There was a shift in proportional mortality over the study period: the contribution of communicable diseases declined and that of noncommunicable diseases and injuries increased. These trends were more marked among men than women. CONCLUSION: The data illustrate that while noncommunicable diseases and injuries are emerging as important contributors to mortality in sub-Saharan Africa, communicable diseases remain significant causes of mortality and should not be neglected. [ABSTRACT FROM AUTHOR]

Objective: To monitor HIV-1 and HIV-2 trends in The Gambia, West Africa., Methods: In 1993-1995 a nationwide survey among 29 670 pregnant women attending eight antenatal clinics estimated the seroprevalence of HIV-1 at 0.6%, and of HIV-2 at 1.1%. Five years later, sentinel surveillance in pregnant women was established, using unlinked anonymous testing in four clinics. A dried blood spot on filter paper was obtained and tested for HIV antibodies., Results: Between May 2000 and August 2001, 8054 analysable samples were collected at four sites. The prevalence of HIV-1 rose sharply in one rural area from 0.6 to 3.0% (P < 0.0001), but the increase was small and non-significant in two other rural sites and in the urban site. The prevalence of HIV-2 did not change significantly at any of the sites. The overall prevalence of HIV-1 was 1.0% [95% confidence interval (CI) 0.8-1.3%], and of HIV-2 0.8% (CI 0.6-1.0%). Site, nationality and higher age were significantly associated with HIV-1 infection, and higher parity and site were significantly associated with HIV-2 infection., Conclusion: Fifteen years after the first case of HIV-1 was described in The Gambia, the epidemic is still at a low level. There is heterogeneity within the country, with one rural area experiencing a fivefold increase in 6 years. The prevalence of HIV-2 in The Gambia is stable.

An epidemic of poliomyelitis caused by poliovirus type 1 occurred in The Gambia in 1986. To determine if a relationship existed between the failure of trivalent oral poliovirus vaccine (OPV) to prevent poliomyelitis and the season when children were vaccinated, 46 children 1-7 years old with poliomyelitis who had received three card-documented doses of OPV were compared with 260 controls who had also received three card-documented doses. Controls were individually matched with children who had poliomyelitis by age, sex, and residence. Children with poliomyelitis were more likely to have received doses in the rainy season (odds ratio describing the linear trend of each additional dose in the rainy season, 1.7; 95% confidence interval, 1.05-2.9). This finding extends previous observations of seasonal difference in the immunogenicity of OPV in The Gambia by showing that season of administration was associated with increased risk of vaccine failure nationwide for a several-year period.

An epidemic of type 1 poliomyelitis involving 305 cases occurred in The Gambia (estimated 1986 population, 768,995) from May through November 1986, following a 6-year period when only five cases were reported. Cases were identified by physician reporting during the epidemic and by a national village-to-village search conducted after the epidemic. The national attack rate was 40 cases per 100,000 people. Cases lived in all parts of the country except the capital, Banjul. The peak month of the epidemic was August (139 cases). The highest attack rate by year of age was in 1-year-old children (394 cases per 100,000 persons), and 75% of cases were 3 years of age or less. A vaccination coverage survey showed that 64% (95% confidence interval 60-68) of 1- to 2-year-old children were vaccinated with at least three doses of trivalent oral polio vaccine at the beginning of the epidemic. Fifty-seven cases became paralyzed more than 2 weeks after a national mass campaign in which 95% of children 1-7 years old were reported to have received a dose of trivalent oral polio vaccine. Experience in The Gambia shows that a several-year period of excellent control of endemic poliomyelitis by a vaccination program can be followed by a major epidemic and that a mass vaccination campaign may be only partially successful in ending the epidemic.

An epidemic of poliomyelitis caused by poliovirus type 1 occurred in The Gambia from May to November 1986. Descriptive findings and vaccination coverage levels are reported in part I. This article (part II) describes a case-control study to estimate the clinical efficacy of three or more doses of trivalent oral polio vaccine compared with zero doses. "Cases" were 1- to 7-year-old children paralyzed during the epidemic who were diagnosed as having poliomyelitis by designated referral physicians. They were identified by reports from referral physicians during the epidemic and by a nationwide village-to-village search after the epidemic. Up to five controls were randomly selected for each case from among children of the same age and sex living in neighboring households. In a matched analysis of 195 cases and 839 controls, the efficacy of three or more doses of trivalent oral polio vaccine was 72% (95% confidence interval 57-82) when children without vaccination cards were considered unvaccinated. The efficacy of three or more doses in 1- to 2-year-old children, in whom the determination of vaccination status was considered to be more accurate than in older children, was 81% (95% confidence interval 66-90). Vaccine failure was not associated with short intervals between doses. Higher levels of vaccination coverage and efficacy than those achieved in The Gambia may be needed in African countries to prevent the return of poliomyelitis as an epidemic disease after it has been controlled as an endemic disease.

A questionnaire administered to subjects seen during a serological survey in The Gambia revealed that knowledge of AIDS and HIV infection was limited. Males, those with a secondary education and people who lived in urban areas had a better understanding but only 17% of women seen in rural areas had any knowledge of the condition. Only 8% of the subjects seen had used condoms in the preceding 12 months; during this time half of them had done so on less than five occasions. Subjects with a secondary education were more likely to have used condoms. A counsellor met 31 asymptomatic seropositive subjects identified during this survey on two occasions. In the majority, the information given caused anxiety rather than modification of behaviour and, at the time of the second interview, only one subject had discussed the situation with the partner and begun using condoms. Some of the cultural factors which may affect the outcome of counselling in an African society are discussed in the light of these findings.