Prevalence of Schistosoma japonicum infection among animals in fifty villages of Samar province, the Philippines.

In the Philippines, there is a need to understand the contribution of different domestic and wild animals in transmitting Schistosoma japonicum infection to humans better. The current study describes variation in animal S. japonicum prevalence across 50 endemic villages of Samar Province, the Philippines. A total of 50 villages were selected, 25 with predominantly rain-fed farms and 25 with some irrigation system. At least 35 cats, dogs, pigs, and water buffaloes each were randomly selected and 30 rat traps were set in each village. Fecal samples were collected for up to three consecutive days for each species. The Danish Bilharziasis Laboratory method (DBL method) was used to determine S. japonicum infection status. A hierarchical logistic regression model with clustering by village and with adjustment for measurement error of the DBL method was used to estimate the prevalence of infection per village and species. Stool samples were collected from 23.4% (1189), 28.6% (1274), 36.3% (1899), and 49.4% (873) of the censused dogs, cats, pigs, and water buffaloes, respectively, and from 663 rats. The adjusted prevalence of S. japonicum infection varied greatly across villages ranging from 1.6% (95% Bayesian Credible Interval: 0.1%-10.2%) to 86.3% (65.9%-97.8%) for dogs, from 0.1% (0%-2.1%) to 21.7% (4.7%-51.2%) for cats, from 0.01% (0.0%%-1.0%) to 18.4% (7.1%-34.7%) for pigs, from less than 0.1% (0.0%-1.2%) to 72.5% (46.0%-97.4%) for water buffaloes, and from 0.7% (0.0%-9.0%) to 95.4% (77.2%-99.9%) for rats. This is the most comprehensive study of animal S. japonicum infection conducted to date. Our results show that, unlike what has been reported in China, very few water buffaloes were infected whereas rats and dogs show high prevalence proportions of infection. This, combined with significant village-to-village variation in prevalence of S. japonicum infection, suggest possible different transmission dynamics of the infection in the Province of Samar in the Philippines and China.

Mid-life onset of dietary restriction extends life and prolongs cognitive functioning.

Fourteen-month-old C57BL/6 (NIA) mice were placed on a nutritionally complete diet providing 139.4 kcal/week. Over a 2-month period the food ration of experimental mice (AE) was reduced to 85 kcal/week, where it remained for the duration of the study. An aged control group (AC) continued with the higher calorie diet. At age 22 months, AC mice and half of the AE mice (AE22) were given a battery of behavioral tests. The remaining AE mice (AE25) were given the test battery at age 25 months. Also, a middle-aged control group (MC) was tested at age 13 months. Midlife onset caloric restriction (CR) increased longevity and preserved strength, coordination, and spontaneous alternation behavior, and altered responses to enclosed alleys. A spatial discrimination in the Morris water maze and a spatial delayed matching-to-sample water-escape task were insensitive to age and diet. The aged mice were adversely affected by testing.

Daily glucose injections facilitate performance of a win-stay water-escape working memory task in mice.

In an experiment that compared 3 versions of a working memory task, male C57BL/6 mice given either 3 (n = 7) or 5 (n = 7) opportunities (test runs) per trial to choose the escape choice section of a maze acquired a win-stay (spatial matching-to-sample) water-escape task. Mice given only 1 test run per trial (n = 6) were unable to perform above chance level. In a 2nd experiment, 14 mice from the 1st experiment were tested for performance on the 3-test-run version of the task. Each mouse was tested for 12 consecutive days with each of 4 doses of glucose (0, 50, 100, & 250 mg/kg ip) given 30 min before testing. The two higher doses increased the percentage of correct test run choices on all 3 daily test runs across the 12 days of testing. Daily glucose injections facilitated the use of trial-dependent information.

An epidemiological study on Schistosoma japonicum in domestic animals in Leyte, Philippines.

An epidemiological study of Schistosoma japonicum in domestic animals in two municipalities of the Eastern coastal plain of Leyte, Philippines, showed that pigs and dogs have the highest rates of prevalence. Dogs had the highest mean 24-hour egg output, and pigs the proportion of hatchable eggs. However, dogs serve an important role in maintaining the transmission of the parasite as indicated by a high transmission potential and the close habitual contact of the animals to human. Although necropsy of 49 dogs and 35 pigs which were coprologically and serologically negative revealed 10 dogs and 6 pigs with adult schistosomes in the mesenteric and portal veins, statistical analysis showed a positive correlation (p less than 0.05) between merthiolate iodine formalin concentration technique and circumoval precipitin test indicating the usefulness of the two tests in field diagnosis of schistosomiasis in domestic animals.