Philippine E-Journals

IDENTIFICATION OF THE SNAIL SECOND INTERMEDIATE HOSTS OF Echinostoma species IN BARANGAY NEW SIBONGA, NABUNTURAN, COMPOSTELA VALLEY

Geromil J. Lara | Winifreda U. de Leon

 

Abstract:

Echinostomiasis is a foodborne, intestinal, zoonotic, snail-mediated parasitosis by the Genus Echinostoma. It is endemic in Southeast Asia and the Far East. In the Philippines, two echinostome species, Echinostoma ilocanum and Echinostoma malayanum infect humans with high prevalence. The foci of pathogen transmission and natural reservoirs are widespread and are linked to fresh or brackish water habitats. Metacercariae, the infective stage of the parasite, are ingested by humans in raw or undercooked fresh or brackish water mollusks, fishes, crustaceans, and amphibians (tadpoles or frogs), which constitute a substantial portion of the diet in endemic areas. The parasite became endemic because of ingestion of the raw second intermediate hosts infected with metarcercariae. The reported snail second intermediate hosts are Pila luzonica (“kuhol”) and Vivipara angularis for Echinostoma ilocanum and Lymnaea (Bullastra) cumingiana for Echinostoma malayanum. This study aimed to identify the snail second intermediate hosts of Echinostoma species as well as the Echinostoma species found in Barangay New Sibonga, Nabunturan, Compostela Valley Province. A total of 2,100 freshwater snails were collected and identified from the research locale. Snail species identified were Pila species, Pomacea canaliculata, and Melanoides juncea. The shells of the snails were cracked and the muscle parts were removed and digested using artificial gastric juice (0.1% pepsin and 0.7% hydrochloric acid) for 1 to 2 hours at 370 Celsius. After incubation, the digested muscle parts were washed with physiologic saline solution (0.9% sodium chloride) and sieved and filtered to separate the sediments from the suspension. The metacercariae recovered were fed to the albino rats by oral gavage. Feces of albino rats were examined 7, 14, and 21 days postinfection for the identification of eggs of Echinostoma using Direct Fecal Smear Technique. Operculated ova measuring 80 to 140 μm by 58 to 90 μm were recovered 21 days post-infection from albino rats inoculated with metacercariae from Pomacea canaliculata snails. The characteristics of the recovered egg were compatible with the characteristics of Echinostoma species eggs. Therefore, the snail second intermediate hosts of Echinostoma species in Barangay New Sibonga, Nabunturan, Compostela Valley Province is possibly Pomacea canaliculata . However, after 21 days post-infection, no adult flukes were recovered from the infected albino rats because of some technical difficulties in the recovery of the minute organism. For this reason, this study was unable to identify the species of Echinostoma, which produces the abovementioned eggs.