1.2 Annual incidence survey
As a continuance of our seroepidemiological surveys to obtain a baseline on the rate of transmission in the west shore of the Lake Naujan, a small amount of blood sample was taken from school children of the grades 1 to 3 (the age group 5-9 years) through finger prick and collected in a capillary tube for COP, ELISA and other immunodiagnoses. The number of blood samples collected totaled up to 427, i.e., 170 in Malabo, 130 in San Pedro and l20 in San Narciso. The samples will be subjected to immunodiagostic studies in the laboratory of Dokkyo University School of Medicine.
1.3 Prevalente surveys in domestic and wild animals
Field surveys on animal infection has been conducted since l996. The number of fecal specimens collected from Malabo, San Pedro and San Narciso are as follows:
All the fecal specimens have been preserved in formalin-detergent solution to examine for schistosome infection in the laboratory of Dokkyo University School of Medicine.
A total of 282 field rats were caught by village volunteers in the 3 barangays and sacrificed by cervical dislocation. At autopsy, the mesentric and portal veins were thoroughly examined for adult flukes and foci due to schistosome infection. 0f 282 rats examined, 37 (l3.1%) were found infectcd.
1.4 Snail survey
0f 178 snails collected in Malabo Forest 7 (3.9%) were found infected with S. japonicum, while only one (1.6%) of 64 snails coIIected in San Narciso Forest was positive. No snail was collected from San Pedro Forest.
2. Bohol
2.1 Snail survey
2.1.1 Omaguin irrigation cannal, pockets, and seepages
Since a new egg-positive case has recently been observed in San Roque, Talibon, a priority search for snails was conducted by Bohol SCT in and around Omaguin. As a result, O.quadrasi snails were found in a smail irrigation canal, some pockets and seepages' in which neither snail survey nor mollusciciding has so far been carried 0ut (Fig. 1 and Table 1).Examinations of 190 snails collected for S. japonicum larvac were made by crushing. Seven (3.7%) were found to be infected with vigorously moving cercariae.
2.l.2 Kanggabok creek and the adjaccnt rice-fields
The team conducted snail survcys in Kanggabok creek and the adjacent rice-fields on 12 August and only four(4) snails were collected in the creek by six(6) well-trained men
