A cross-sectional study of the prevalence of intensity of infection with Schistosoma japonicum in 50 irrigated and rain-fed villages in Samar Province, the Philippines

BACKGROUND: Few studies have described heterogeneity in Schistosoma japonicum infection intensity, and none were done in Philippines. The purpose of this report is to describe the village-to-village variation in the prevalence of two levels of infection intensity across 50 villages of Samar Province, the Philippines. METHODS: This cross-sectional study was conducted in 25 rain-fed and 25 irrigated villages endemic for S. japonicum between August 2003 and November 2004. Villages were selected based on irrigation and farming criteria. A maximum of 35 eligible households were selected per village. Each participant was asked to provide stool samples on three consecutive days. All those who provided at least one stool sample were included in the analysis. A Bayesian three category outcome hierarchical cumulative logit regression model with adjustment for age, sex, occupation and measurement error of the Kato-Katz technique was used for analysis. RESULTS: A total of 1427 households and 6917 individuals agreed to participate in the study. A total of 5624 (81.3%) participants provided at least one stool sample. The prevalences of those lightly and at least moderately infected varied from 0% (95% Bayesian credible interval (BCI): 0%–3.1%) to 45.2% (95% BCI: 36.5%–53.9%) and 0% to 23.0% (95% BCI: 16.4%–31.2%) from village-to-village, respectively. Using the 0–7 year old group as a reference category, the highest odds ratio (OR) among males and females were that of being aged 17–40-year old (OR = 8.76; 95% BCI: 6.03–12.47) and 11–16-year old (OR = 8.59; 95% BCI: 4.74–14.28), respectively. People who did not work on a rice farm had a lower prevalence of infection than those working full time on a rice farm. The OR for irrigated villages compared to rain-fed villages was 1.41 (95% BCI: 0.50–3.21). DISCUSSION: We found very important village-to-village variation in prevalence of infection intensity. This variation is probably due to village-level variables other than that explained by a crude classification of villages into the irrigated and non-irrigated categories. We are planning to capture this spatial heterogeneity by updating our initial transmission dynamics model with the data reported here combined with 1-year post-treatment follow-up of study participants

Oogram studies in mice infected with Schistosoma mansoni and treated with dexamethasone

Mice infected with about 90 cercariae of Schistosoma mansoni (LE strain) were treated during five consecutive days with dexamethasone (50 mg/Kg, subcutaneously), starting on the 42th day of infection. Groups of five mice were then daily sacrificed from the first day after onset of treatment until the first day after. The perfusion of the portal system was performed and a piece of the intestine was processed for qualitative and quantitative oograms. This treatment carries to larger numbers of eggs in the tissues of treated mice, when compared with untreated groups. No changes were observed in the kinetics of oviposition, as all stages of viable eggs were observed in the tissues of treated and control mice. These data reinforce the hypothesis of a partial blockade of the egg excretion in immunossupressed mice.Camundongos infectados com cerca de 90 cercárias da cepa LE de Schistosoma mansoni foram tratados durante 5 dias consecutivos com dexametasona (50mg/ Kg, subcutaneamente) a partir do 42º dia de infecção. Grupos de cinco camundongos foram sacrificados diariamente após o primeiro dia do início do tratamento até o primeiro dia após o término. A perfusão do sistema porta foi feita e fragmentos do intestino foram processados para a realização de oogramas qualitativos e quantitativos. O tratamento leva a um maior número de ovos nos tecidos dos camundongos tratados, se comparado com os grupos não tratados. Nenhuma mudança foi observada na cinética de oviposição, e ovos viáveis em todos os estádios evolutivos foram observados nos tecidos de camundongos tratados e controles. Estes dados reforçam a hipótese de um bloqueio parcial na saída de ovos dos tecidos do intestino para o lúmem intestinal em camundongos imunossuprimidos

Children and AIDS

Children with AIDS are a small but growing population who present unique policy and practice challenges. Social workers must develop an understanding of the needs of this population and their families. Social supports must be created and worker skills must be developed. </jats:p