Zoonotic organisms in selected species of freshwater gastropods in Lanao del Norte, Mindanao, the Philippines

摘要

Urgency and worldwide attention are now focused on parasites causing zoonotic diseases. An inventory of parasites inhabiting the previously identified freshwater gastropods in Lanao del Norte is the next step necessary to elucidate and determine the etiology of zoonoses. Four sampling sites, composed of thirty areas within the Municipalities of Lala, Kapatagan, and Salvador from the island of Mindanao, the Philippines, were thoroughly searched in this study from February to August 2018 using an explorative-investigative study design. Out of the 2,460 sampled individuals, eight species of gastropods were observed and collected, namely: Melanoides tuberculata, Melanoides turriculus, Tarebia granifera, Pomacea canaliculata, Oncomelania quadrasi, Gyraulus crista Linn., Vitta virginea and Radix. These snails were then cleaned and rinsed with water and were then brought to the laboratory for examination. Small Sizes of snails were crushed, while the larger sizes were subjected to shedding. The parasites sampled were then identified using key manuals. After the examination, three morphotypes of cercariae were sampled and recorded in this study, namely: Vivax cercariae, schistosome cercariae, and Pigmentata amphisome cercariae. Two parasitic protozoans (Paramecium and Entamoeba coli) and one parasitic microscopic animal (rotifer) were also sampled. Paramecium and E. coli were found out to be the most prevalent in all the parasites. Although these species were reported to be of no ecological and medical significance, they were also reported to cause physiological effects to the host snails. Schistosome cercariae and Pigmentata amphisome cercariae observed were of significant medical importance; thus, since these snails were found near in areas where there are human dwellings, the transmission of diseases caused by parasites vectored by these snails is possible. It is, therefore crucial that there is a need to implement proper sanitation practices in the communities and adequate management of these snails to prevent, manage, and control the transmission of diseases caused by the parasites.