Paul Bouvier

What does a single determination of malaria parasite density mean? A longitudinal survey in Mali

Summary Temporal variations of blood parasite density were evaluated in a longitudinal study of young, asymptomatic men in a village with endemic malaria in Mali (West Africa). Our main intention was to challenge the value of a single measure of parasite density for the diagnosis of malaria, and to define the level of endemicity in any given area. Parasitaemia and body temperature were recorded three times a day in the wet season (in 39 subjects on 12 days) and in the dry season (in 41 subjects on 13 days). Two thousand nine hundred and fifty seven blood smears (98.5% of the expected number) were examined for malaria parasites. We often found 100‐fold or greater variations in parasite density within a 6‐hour period during individual follow‐up. All infected subjects had frequent negative smears. Although fever was most likely to occur in subjects with a maximum parasite density exceeding 10000 parasites/mm3 (P = 0.009), there was no clear relationship between the timing of these two events. Examples of individual profiles for parasite density and fever are presented. These variations (probably due to a ‘sequestration‐release’ mechanism, which remains to be elucidated) lead us to expect a substantial impact on measurements of endemicity when only a single sample is taken. In this study, the percentage of infected individuals varied between 28.9% and 57.9% during the dry season and between 27.5% and 70.7% during the wet season. The highest rates were observed at midday, and there were significant differences between days. Thus, high parasite density sometimes associated with fever can no longer be considered as the gold standard in the diagnosis of malaria. Other approaches, such as decision‐making processes involving clinical, biological and ecological variables must be developed, especially in highly endemic areas where Plasmodium infection is the rule rather than the exception and the possible causes of fever are numerous.

Typology and correlates of sexual abuse in children and youth: multivariate analyses in a prevalence study in Geneva ☆

OBJECTIVE Child sexual abuse (CSA) encompasses a variety of distinct situations, which should be differentiated. There is a need for a working classification, taking into account various parameters. METHODS The Geneva CSA prevalence study was based on 1116 randomly selected adolescents aged 14 to 16. Secondary analyses of the 252 reported cases of abuse was carried out using a multivariate approach combining multiple correspondence analysis and automatic classification, leading to descriptive analyses and to a new classification of CSA. RESULTS Global prevalence of CSA, using a broad definition, was 10.9% for boys, and 33.8% for girls. Classification of cases of abuse differentiated 5 classes: (A) exhibitionism or other abuse without contact, by an adult (proportion of cases in boys: 22%; girls: 32%); (B) abuse of an adolescent boy by a peer without contact (62%); (C) abuse of an adolescent girl by a peer with physical contact (38%); (D) abuse inside the family, repeated (boys: 10%, girls: 16%); (E) child abuse with genital penetration, lasting 2 years or more (boys: 7%; girls: 14%). CONCLUSIONS CSA is a complex and heterogeneous problem. Reported abuse situations can be classified into five classes, with different degrees of severity, causes, and consequences. Classification is essential in clinical research as well as in the design and conception of prevention programs.

Preventing sudden infant deaths — the slow diffusion of an idea

The sudden infant death syndrome (SIDS) is among the leading causes of post-neonatal mortality in industrialised countries. Research has highlighted that many of these deaths are avoidable by adopting a few simple precautions. These include sleeping in the supine position, avoiding exposure to tobacco smoke, breast feeding where possible, and avoiding over heating. The paper traces the development of understanding of the role of sleeping position in the aetiology of SIDS and the diffusion of this knowledge among and within industrialised countries. In retrospect, evidence began to become available in the early 1980s but it was several years before it was acted upon, initially in The Netherlands and subsequently in New Zealand, the United Kingdom and Scandinavia. Several countries have mounted major national preventive campaigns, of various kinds, each of which has been associated with a reduction in deaths from SIDS, but others have not. The reasons for these differences are explored. The evidence for a causal link between sleeping position and SIDS is now very strong and the costs of implementing a policy to change behaviour is small, compared with other health care interventions. This information is now widely available in the international literature. The example of SIDS provides information on the barriers to adoption of knowledge as well as the factors that promote it.

Some doubts about one of the largest smoking prevention programmes in Europe, the smokefree class competition.

With over 600 000 participants in 16 countries, the smokefree class competition is one of the largest smoking prevention programmes in Europe. Participating classes that maintain a smoking prevalence usually below 10% are eligible for a contest and the winner is rewarded with money. There is however no convincing evidence that this competition has any effect on smoking prevalence beyond the short term, and this approach raises serious ethical issues. In particular, the central principle of this competition is to apply negative peer pressure upon teenage smokers. However, promoters of this competition have neglected to report the possible adverse consequences of using negative peer pressure upon smokers. This is a concern, because teenage smokers are more vulnerable than non-smokers, and they are at higher risk of suffering from psychological problems and school failure.