No abstract

An immunoglobulin G enzyme-linked immunosorbent assay (IgG-ELISA) for the detection of dengue antibodies is described and compared to the haemagglutination inhibition test (HI). The sensitivity, specificity and agreement rate between the 2 techniques were good. The coefficients of correlation between IgG-ELISA and HI results, using dengue 1-4 antigens, were highly significant (P less than 0.001 for either antigen). IgG-ELISA was rapid, and easy to perform and suitable for large-scale studies. Between April and June 1987, a baseline serosurvey of the prevalence of dengue antibodies in age-stratified samples of children was carried out in Tahiti using IgG-ELISA. 327 children were tested against each dengue serotype. There was no significant difference between sex. Overall rates ranged from 7.4% in children under 5 years to 83.1% in those aged 15-19 years. Dengue 4 being the only serotype involved since 1979, specific responses to dengue 4 were found in higher proportion among children under 8 years old, while the IgG-ELISA responses were more widely reactive among children aged above 8 years (P less than 0.001). The acquisition rate of dengue 4 antibodies was 2.95% on average per year in children under 8 years of age.

The sophisticated technical design of 2SE FAG has resulted in a system which is able to carry out its role as an early warning system. Efforts must be concentrated on increasing its acceptance and use by people who have to enter data and decreasing the occurrence of the frequency of technical problems.

To investigate if the characteristics of human intestinal Escherichia coli are changing with the environment of the host, we studied intestinal E. coli from subjects having recently migrated from a temperate to a tropical area. We determined the phylogenetic group, the prevalence of the antibiotic resistance, the presence of integrons and the strain diversity in faecal isolates from 25 subjects originally from metropolitan France and expatriated to French Guyana. These characteristics were compared with those of 25 previously studied Wayampi Amerindian natives of French Guyana and from 25 metropolitan French residents. The three groups of subjects were matched for age and sex, had not taken antibiotics for at least 1 month, nor had been hospitalized within the past year. In all, the characteristics of intestinal E. coli from Expatriates were intermediate between those found in residents from metropolitan France and those found in natives of French Guyana. Prevalence of carriage of resistant Gram-negative bacteria in Expatriates was intermediate between French residents and Wayampi as were the prevalence of integrons in E. coli (12.3% versus 16.3% and 7.8% respectively), and the intra-host diversity of E. coli (2.3 strains/subject versus 1.9 and 3.1, respectively); lastly, in Expatriates, the prevalence of carriage of phylogenetic group B2 strains was lower than in French residents (16% versus 56%, P = 0.005), while carriage of phylogenetic group A strains was lower than in Wayampi (56% versus 88%, P = 0.03). Our results suggest that the composition of the commensal intestinal flora of humans is not static but changes dynamically in response to new environmental conditions.

Background: Malaria chemoprophylaxis compliance is suboptimal among French soldiers despite the availability of free malaria chemoprophylaxis and repeated health education before, during and after deployment to malaria endemic areas.