Nasopharyngeal carriage of pneumococci in Gambian children and in their families.

BACKGROUND: Nasopharyngeal carriage of pneumococci is prevalent among children in developing countries but little is known about the relationship of nasopharyngeal carriage to invasive disease or about the way in which pneumococci spread within households. OBJECTIVES: To determine the prevalence of nasopharyngeal carriage in healthy and sick Gambian children and to investigate transmission within households. METHODS: Nasopharyngeal swabs were obtained by the per nasal route and cultured for pneumococci on selective media. Pneumococci were serotyped with the use of latex particles coated with type-specific antisera. RESULTS: Pneumococci were isolated from the nasopharynx of 73 (90.1%) of 81 children with invasive pneumococcal disease, 86 (76.1%) of 113 healthy, age-matched control children and 911 (85.1%) of 1071 sick children. Pneumococci belonging to serotypes 1, 14 and 12 were isolated significantly more frequently from cases than from matched controls. In 43 (76.8%) of 56 children with invasive disease, pneumococci isolated from the nasopharynx and from the blood or other sterile site belonged to the same serotype. Pneumococci of the same serotype as the bacterium responsible for invasive disease in a child were obtained from 72 (8.5%) of 843 family members, most frequently from young siblings of the case patients. CONCLUSION: Nasopharyngeal carriage of pneumococci is more prevalent among young Gambian children than among adults and invasive infections are probably acquired more frequently from siblings than from parents. However, further studies are needed to confirm this hypothesis with more discriminating markers than polysaccharide serotyping.

The shortened dental arch: supplementary analyses from the 1988 adult dental health survey.

Information on 2297 dentate adults, aged 15-75+ years, who participated in the 1988 national survey of adult dental health in the United Kingdom, was reviewed in order to determine what proportion in each age group fulfilled the criteria for a 'shortened dental arch'. The proportion of people with four good quadrants was 90 per cent at 16-24 years falling to 2 per cent at 65-74 years. Overall, 54 per cent of the sample had four good quadrants. This is a more stringent measure of dental health than the proportion with 21 or more standing teeth, where the corresponding values were 100 per cent, 24 per cent and 80 per cent.

The limitations of verbal autopsy in a malaria-endemic region.

Verbal autopsies are being used widely to describe the causes of mortality and to assess the effect of interventions against specific diseases in developing countries where many deaths occur at home. A verbal autopsy has been in use in the Upper River Division of The Gambia since 1988. In this paper we present the results of a validation study of this technique. One hundred and forty-one verbal autopsies were reviewed on two occasions by the same three physicians. In 38 (27%) of the cases, the first and subsequent diagnoses differed. In 94 children admitted to Basse Health Centre, the results of verbal autopsies were compared with the diagnoses made by a paediatrician--only 44 (47%) matched. The poor sensitivity and specificity of the verbal autopsy in this study may have been due to the confounding effect of malaria, which can be difficult to distinguish from other causes of death in this community.

Psychosis and cannabis abuse in The Gambia. A case-control study.

Cannabis abuse is a major public health problem in The Gambia and other parts of West Africa, and the rise in the incidence of psychotic illness reflects the increased background use of cannabis by the local population. A case-control study was performed to determine the association between psychosis and cannabis abuse in The Gambia and the importance of other risk factors. Out of 234 patients admitted to Campama Psychiatric Unit over 12 months, 210 (90%) were enrolled in a case-control study. Urine was tested for cannabinoid substances and 38% were positive compared with 12% of matched non-psychotic control subjects. Analysis of the matched pairs showed that a positive urinary cannabinoid test, cigarette smoking, alcohol consumption, travel to Europe and family history of mental illness were all significant risk factors for psychotic illness; Koranic education reduced the risk. There was a positive correlation among the psychotic patients between a positive urinary cannabinoid test and the use of alcohol, ataya tea and cigarette smoking; a family history of mental illness showed a negative correlation.

Overlap in the clinical features of pneumonia and malaria in African children.

Pneumonia and malaria are common causes of childhood morbidity and mortality in many developing countries and simple guidelines have been proposed to facilitate their diagnosis by relatively unskilled health workers. We have studied children in The Gambia attending out-patient and under-five clinics with clinically suspected pneumonia (cough or difficulty in breathing and a raised respiratory rate) during periods of high or low malaria transmission. During a period of high malaria transmission, 33% of these children had radiological evidence of pneumonia (with or without malaria parasitaemia) compared to 38% who had malaria parasitaemia, no radiological evidence of pneumonia and no other obvious cause of fever. Corresponding figures during a period of low malaria transmission were 48% and 6% respectively. The clinical overlap between pneumonia and malaria has important implications for case management strategies and evaluation of disease-specific interventions in regions in which both pneumonia and malaria are prevalent.

Decline in meningococcal antibody levels in African children 5 years after vaccination and the lack of an effect of booster immunization.

Antibodies to group A meningococcal polysaccharide were measured by hemagglutination (HA) and by ELISA in sera obtained from Gambian children before vaccination and 3 weeks, 2 years, and 5 years after vaccination with a group A + group C meningococcal capsular polysaccharide vaccine. Children were 1-4 years old at the time of vaccination. Most showed a good initial response to vaccination, including those aged 1-2 years. However, antibody titers declined progressively during follow-up, and 5 years after vaccination, antibody titers measured by both HA and ELISA had returned to prevaccination levels. This decline was not influenced significantly by a booster dose of vaccine given 2 years after initial immunization. Administration of malaria chemoprophylaxis reduced the rate at which antibody levels fell after initial immunization. Sustained protection of children against group A meningococcal disease will require the development of vaccines that are immunogenic in infants and that can induce T cell memory.

The effect of temperature reduction on respiratory rate in febrile illnesses.

A raised respiratory rate is a useful sign in the diagnosis of pneumonia in children. It was observed that children with malaria and other febrile illnesses may also present with a raised respiratory rate. To determine the extent to which increased body temperature contributes to the raised respiratory rate observed in these children the effect of change in body temperature on respiratory rate was measured in 186 sick Gambian children with a raised respiratory rate, including those with pneumonia or malaria. A temperature dependent effect on respiratory rate of 3.7 breaths per minute per degree centigrade was demonstrated for the whole study cohort, with no significant difference between children with pneumonia or malaria. Twenty three per cent of children with pneumonia whose temperature fell had a final respiratory rate below that currently recommended by the World Health Organisation for the diagnosis of pneumonia. It is concluded that respiratory rate is to some extent dependent on body temperature in children with febrile illnesses such as pneumonia and malaria, but that this does not alone account for the raised respiratory rate seen in these children. The effect of reduction in body temperature on respiratory rate does not help to distinguish children with pneumonia from those with malaria. A history of recent use of an antipyretic or other measures to control fever is important when evaluating children for possible pneumonia.

Severe malaria in Gambian children is not due to lack of previous exposure to malaria.

The reasons why only a small proportion of African children infected with Plasmodium falciparum develop severe or fatal malaria are not known. One possible reason is that children who develop severe disease have had less previous exposure to malaria infection, and hence have less acquired immunity, than children who develop a mild clinical attack. To investigate this possibility we have measured titres of a wide range of anti-P. falciparum antibodies in plasma samples obtained from children with severe malaria, children with mild malaria and from children with other illnesses. Mean antibody levels in patients with malaria were higher than those in patients with other conditions but, with only one exception, there were no significant differences in antibody titres between cases of severe or mild malaria. A parasitized-erythrocyte agglutination assay was used to estimate the diversity of parasite isolates to which children had been exposed; plasma samples obtained from children with cerebral malaria recognized as many isolates as did samples obtained from children with mild disease. Our findings do not provide any support for the view that the development of severe malaria in a small proportion of African children infected with P. falciparum is due to lack of previous exposure to the infection.