Three phylogenetic groups have driven the recent population expansion of Cryptococcus neoformans.

Cryptococcus neoformans (C. neoformans var. grubii) is an environmentally acquired pathogen causing 181,000 HIV-associated deaths each year. We sequenced 699 isolates, primarily C. neoformans from HIV-infected patients, from 5 countries in Asia and Africa. The phylogeny of C. neoformans reveals a recent exponential population expansion, consistent with the increase in the number of susceptible hosts. In our study population, this expansion has been driven by three sub-clades of the C. neoformans VNIa lineage; VNIa-4, VNIa-5 and VNIa-93. These three sub-clades account for 91% of clinical isolates sequenced in our study. Combining the genome data with clinical information, we find that the VNIa-93 sub-clade, the most common sub-clade in Uganda and Malawi, was associated with better outcomes than VNIa-4 and VNIa-5, which predominate in Southeast Asia. This study lays the foundation for further work investigating the dominance of VNIa-4, VNIa-5 and VNIa-93 and the association between lineage and clinical phenotype.

Geographical heterogeneity of dengue transmission in two villages in southern Vietnam.

This study was performed to test the hypothesis that there are 'hotspots', i.e. geographical heterogeneity, of dengue transmission. Data from two repeat serosurveys in two villages in Vietnam were used to identify incident infections and to relate these to prevalence at baseline and thus assess geographical heterogeneity, i.e. clustering, in dengue transmission. A total of 400 households were surveyed; serological data from 521 children at baseline and from 119 children at follow-up were included in a spatial analysis. Geographical heterogeneity of dengue transmission was explored using a permutation null distribution test. This showed for the first time evidence of clustering of dengue virus transmission at the household level in asymptomatic children. Risk areas could be identified by seroprevalence surveys combined with mapping. Control of dengue virus transmission could be supported by identification and control of hotspots.

Nutritional status following malaria control in a Vietnamese ethnic minority commune.

OBJECTIVE: To study whether control of malaria leads to catch-up growth or an increase of obesity in a marginally nourished population. SETTING: A Vietnamese ethnic minority commune in southern Vietnam. DESIGN: Repeated annual anthropometric surveys were performed from 1995 to 2000. Z-scores for height, weight and BMI for age and weight-for-height were determined by using NCHS 1978 and CDC 2000 reference tables and by the LMS method. INTERVENTION: Active malaria control that reduced the parasite carrier rate from 50% in 1994 to practically nil in 1998. RESULTS: Inhabitants were generally of short stature and very thin. Using the US reference tables, the prevalence of moderate/severe stunting among children was 53/24% and of wasting 27/9% in the first survey in 1995. Physical condition and normal daily activities of most inhabitants were normal. The repeated LMS-Z-scores uncovered a significant recovery of stunting, extending into preadolescence, including the development of a pubertal growth spurt for girls and enhancement of pubertal growth in boys, after control of malaria. The mean (95% CI) annual increase of Z-height-for-age was 0.11 (0.09-0.12) for boys and 0.14 (0.13-0.15) for girls (P<0.001). As a consequence, weight-for-age and BMI Z-scores decreased without indication of developing obesity. CONCLUSION: Catch-up growth, extending into preadolescent age, was observed in a Vietnamese ethnic minority population with a chronic state of low food intake, without indication of developing obesity. The control of malaria was probably the most significant contribution to this catch-up growth.

Atovaquone-proguanil for recrudescent Plasmodium falciparum in Vietnam.

Malarone, a fixed combination of atovaquone with proguanil (AP), has recently been recognized as a promising treatment against multidrug-resistant Plasmodium falciparum. In Vietnam, the first-line treatment for P. falciparum malaria is currently a combination of mefloquine and an artemisinin derivative, and the use of AP has not been explored. The aim of the present study, based in Vietnam, was to assess the efficacy of AP when used to treat P. falciparum recrudescences that had occurred after primary treatment with mefloquine-artesunate. All but two of the 39 patients investigated completed follow-up. The mean parasite- and fever-clearance times [and 95% confidence intervals (CI)] after AP treatment were 36 (30-42) and 21 (18-24) h, respectively. Most (32) of the 37 infections that were followed adequately appeared to be eradicated by the AP, the other five recrudescing once more. The overall cure 'rate' and (CI) was 86% (76%-98%). All of the patients tolerated the AP well. Atovaquone-proguanil appears to be a safe and promising alternative treatment for P. falciparum infections in South-east Asia, although the combination is relatively expensive and may not clear some infections with multidrug-resistant parasites.