Conclusions — a Geomedical View

Abstract

The epidemiological and geomedical situation of the occurrence and distribution of helminths in the Philippines is in part determined by the particular geographical location of the archipelago between the Asian continent and the Pacific region. The isolation of this border region has, for instance, led to the origin of a sub-species of the Japanese blood fluke, which evolved together with Oncomelania hupensis quadrasi, its intermediate host snail, and remains restricted to the Philippines. Largely restricted to the Ilocos region, intestinal capillariasis, too, may be regarded as specific to the Philippines despite the recent evidence of isolated cases in Thailand and Japan. This includes the complete absence of certain helminth species auch as Fasciolopsis buski and Opisthorchis sinensis, which are very common in some regions of the Asian continent but which were unable to become endemically established in the Philippines, in spite of apparently suitable ecological conditions, although time and time again immigrants from the mainland have been found to be infected.