Lymnaea (Bullastra) cumingiana Pfeiffer (Pulmonata: Lymnaeidae) : second intermediate host of Echinostoma malayanum in the Philippines
Monzon, R.B.; Kitikoon, V.
Southeast Asian Journal of Tropical Medicine and Public Health 20(3): 453-460
1989
ISSN/ISBN: 0125-1562 PMID: 2633353 Document Number: 328995
Adult flukes were obtained from rats and hamsters fed with metacercariae isolated from L. (B.) cumingiana collected in Isabela and Laguna, Luzon, Philippines, and were identified as E. malayanum based on the presence of a circumoral collar of 43-45 spines and the highly lobed testes. This discovery is of public health significance because L. (B.) cumingiana is eaten raw by certain local populations in northern Luzon. Cathaemasia cabrerai (Jueco and Monzon, 1984) is considered invalid because it apparently was based on E. malayanum flukes that had lost their circumoral collar of spines after treatment with praziquantel and bithionol. This is the first case where L. (B.) cumingiana has been proven to be of medical importance in the Philippines (as the natural 2nd intermediate host of E. malayanum). The first intermediate host and reservoir host are still unknown. Previously, only E. ilocanum was reported in the Philippines. Adult flukes obtained from laboratory rats and hamsters fed with metacercariae from Lymnaea (Bullastra) cumingiana were identified as Echinostoma malayanum. L. (B.) cumingiana is eaten raw by some local populations in northern Luzon. Human infection with an intestinal fluke (named Cathaemasia cabrerai) has been recorded in northern Luzon. The authors now suggest that "C. cabrerai" was actually E. malayanum which had lost its circumoral collar of spines following chemotherapy. The public health importance of L. (B.) cumingiana and the epidemiology of E. malayanum are discussed.Sheila M. Crewe.