Bayani L. BLAS
Rogelio HAMBRE
Schistosomiasis Control Service, Department of Health, Manila 2805, Philippines.

Yuji IRIE
Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki 305, Japan.

Naoako, NIHEI
Department fo Parasitology, National Insitite of Health, Tokyo 169, Japan.

Hiroshi OHMAE
International Medical Cnter, Tokyo 169, Japan.

Rogelio PANGILINAN
Crispina AUTENTICO
Schistosomiasis Control Team, Trinidad, Bohol 6432, Philippines.

Hiroshi TANAKA
Japan Overseas Cooperation Volunteers, Tokyo 151, Japan.

ABSTRACT
An isolated focus of schistosomiasis covering an area of 2.000 ha is confined in the northeastern part of the Island of Bohol. Philippines. An ambitious program to eliminate schistosomiasis was initiated on the Island in February 1986. The main control strategies are: (l) to control snails by clearing of vegetation and applying of chemical molluscicides at six-month intervaIs supplemented with agro-engineering environmental measures such as filling. ponding. cement-lining. and converting to ricefields with improved farming practices; and (2) to find cases by stool examination to diagnose and treat positive cases. Since August 1994. no Oncomelnia quadrasi, the intermediate snail host of Schistosoma japonicum, has been observed in all the 15 snail habitats. In 1995. 8.779 stool samples (70.8% of the target population) were examined in the endemic villages. The number of positive was only seven. giving a prevalence of 0.08%. To know the prevalence among the different mammal reservoirs. 86 dogs. 57 pigs. 97 carabaos (water buffaloes). 93 cows. 51 goats and 122 field rats in the endemic villages were examined for schistosome infection in February 1996. Only one rat (0.82%) was found to be infected. The island province of Bohol is now on the verge of eliminating Oncomelnia quadrasi snails and schistosomiasis.