Freshwater molluscs as hosts of digenetic trematode from a metropolitan area of Maranhão island, BrazilMoluscos límnicos como hospedeiros de trematódeos digenéticos de uma região metropolitana da ilha do Maranhão, Brasil

Abstract

This study is the first malacological survey of freshwater and trematode larvae, without restriction, only to transmit species of schistosomiasis for the Maranhão island. Thus, this study aimed to characterize the diversity of limnic molluscs and his helminth parasites in environments with varying ecological aspects. Specimens of gastropod were collected monthly in the São Luís city during the period from November 2014 to June 2015 in four collection points (P1 - lentic and impacted P2- lotic and impacted P3 - lotic and amended, P4 - lotic and preserved). For each area were recorded pH and dissolved oxygen, as well as analysis of Total Coliforms. A total of 4112 limnic snails were collected, classified as follows: Biomphalaria glabrata Say, 1818 (62.87%), B. straminea Dunker, 1848 (24.66%), Pomacea sp. Perry, 1810 (7.93%), Physa sp. Draparnaud, 1801 (3.42%) e Drepanotrema sp. Crosse & Fischer, 1880 (1.12%). Of these, B. glabrata were positive for S. mansoni cercariae. Physa sp. and Pomacea spp. they were infected with xiphidiocercaria. There were significant positive correlation for precipitation in relation to the amount of molluscs (p <0.05). The highest abundance of molluscs was registered in impacted areas as well as higher level of parasitism. They are considered first reports for the Maranhão island: Pomacea sp, Physa sp, Drepanotrema sp. and xiphidiocercaria.