The endemicity of schistosomiasis japonica in Sorsogon, Southeastern Luzon

For the first time, the endemicity of Schistosomiasis japonica in Irosin, Sorsogon has been definitely established, with the finding of both Oncomelania quadrasi snails and 22 human cases who had contracted the disease there. This is the first town in the island of Luzon so declared; and judging from conditions of climate and topography (low rice lands, and abundant streams) the neighboring towns of Juban and Bulan may also be marked as probable endemic fociIncidentally, it has also been found that paragonimiasis could be endemic in Irosin with the discovery of one case in a child of 7 years who had never left the town, and the presence of infected crabs in the place. (Summary and Conclusion)

The physiological labelling of schistosoma japonicum cercariae with carbon 14

The snails (Oncomelania quadrasi) fed with C labelled sugars, proteins and phospholipids shedded labelled cercariae after 72-96 hours. Autoradiographs of whole worms developing from labelled cercariae shedded from snails fed with C labelled sugars and phospholipids showed that the label was retained and the radioactivity was distributed uniformly throughout the whole fluke. The level of activity was high, especially with flukes developing from C labelled sugar cercariae, having an activity of 49 cpm per organism. The activity can be retained 37 days after their penetration of the body of the infected host. The value of our findings in the investigation of certain problems in schistosomiasis research have been discussed. (Summary)

Studies on schistosomiasis: Second progress report on mass survey and other accomplishments as of December 31, 1951

From one field unit trained, equipped, and organized in 1949-later increased to six in 1950, then to eight in the early part of 1951-but which was reduced to seven toward the end of the same year,-we have been able to make extensive fact-finding surveys of 132 towns of 16 provinces in the Philippines continuously for two and one-half years ending on December 31, 1951. The results obtained in these surveys are presented in this paper, with tables and maps showing the incidence and distribution of the diseaseEndemic areas were definitely established in 61 towns of 12 provinces, 123,291 people were examined, and a total of 10,796 cases were found positive on stool examination, giving a general incidence of 12.2%. Of these cases, 5,318 were treated with Fuadin; and 272, with NilodinSnail surveys in all these towns except one (Barugo) revealed many streams and swamps positive for Oncomelania quadrrasi snails. The spotty distribution of the snail population was quite striking-the snail density ranging from a few to several hundreds per square meter. An index of all these spots (816 in all) which were found positive for Oncomelania quadrasi snails was prepared with the corresponding map for each town. These indexes and maps now form the bases of our studies on snail controlOur previous finding in 1950 showing the exceedingly high incidence of intestinal parasitism, reaching 98.79% even in areas where schistosomiasis was not found, was further confirmed in these series of 123,291 stool examinations, with an incidence of 97.82%. We also found an incidence of 85.77% for arcariasis; 52.7% for trichuriasis; and 38.75% for hookworm infectionWith the conclusion of these surveys, it is anticipated that, given more time for the analysis and study of the data obtained, and with the forthcoming technical assistance from the WHO, we may be able to prepare a well-balanced national schistosomiasis control program which we hope will be possible of implementation in the near future. (Summary)

Screening of chemical compounds for molluscicidal activity against Oncomelania quadrasi

In view of the inherent problems associated with the medical, sanitary and educational approach to the control of schistosomiasis, it is the consensus that the control of the small intermediate host offers a better and more effective means of reducing the transmission of the disease. Having achieved some degree of success in the ecological control of the snail host (Oncomelania quadrasi) in the Philippines as shown by the evaluation done in 1962 by Hairston, a WHO Consultant it has nevertheless been noted that due to the varied hopographic characteristics of small areas, complete eradication may not be attained in certain instances. For it was noted that snails had continued to thrive in small pockets after ecological control measures had been applied. Molluscicides at this stage, therefore, could be used to great advantage as a terminal measure. (Author)