สัณฐานวิทยาและพยาธิสภาพของปรสิตบางชนิดในพื้นที่ อพ.สธ. : รายงานวิจัย

Abstract

This study was done in two parts. The first part involved the prevalence, morphology and histopathology of blood parasites in amphibians and reptiles. Blood samples were collected from 161 animals in two locations between 2012 and 2013. Blood specimens were examined using thin-filmed blood smear preparations with Giemsa staining. In location 1, mo ko Surin National Park, Pang Nga province, a total of 60 amphibians (4 species) 5 were positive for blood parasites (prevalence = 8.33%) infecting only Rana erythraea. The observed parasites included Trypanosoma chatonii and Aegyptianella sp.. Of 13 reptiles (8 species) only 1 Cyrtodactylus surin was positive with the presence of Hepotozoon sp. (prevalence = 7.69%). In location 2, mo ko Lanta National Park, Krabi province, of 84 amphibians (7 species) 14 were positive for blood parasites (prevalence = 16.67%) infecting 4 host species, Limnonectes blythii, Fejervarya limnocharis, Bufo parvus and Limnonectes jarujini. The observed parasites included Aegyptianeila sp., Hepatozoon sp., lankesterella sp., Trypanosoma chattonii, Trypanosoma sp., microfilaria and unknown. Of 4 reptiles (2 species) only 2 Mabuya mulitfasciata was positive for microfilaria (prevalence = 50%). Microscopic observation revealed that red blood cells infecting with Hepatozoon gametocytes were hypertrophied and the nucleus of the host cell was displaced laterally. The second part, the prevalence and morphology of cercariae found in freshwater snails from Khao Kheow Open Zoo, Chonburi province were investigated during November 2012 to January 2013. The snails were collected by handpicking from six sites. The total number of 1,446 snails representing 7 species was collected. They were 602 Filopaludina martensi, 377 Lymnaea rubiginosa, 208 Lymnaea sp., 16 Indoplonorbis exustus, 22 Melanoides tuberculata and Clea Helena and 221 Pomacea canaliculata. The snails were examined for cercariae using crushing methods. The morphology of cercariae was studied as alive, stained and scanning electron microscopy. The results showed that the overall cercariae infection rate was 1.31% (1,446/19). The cercariae were identified into 4 groups 6 types, furcocercous cercariae (Fc.type1, Fc.type2), gymnocephalous cercaria of pleurolophocerous type (Gc.), pleurolophocercous cercariae (Pc.), and xiphidiocercariae (Xc.type1, Xc.type2). At the site 1, 3 and 6 the snails were not infected. At the site 2, 3.76% Lymnaea rubiginosa were infected with Fc.typel, Fc.type2 and Gc. At the site 4, 0.83% of Filopaludina martensi were infected with Xc.type1. At the site 5, 2.0% of Filopaludina martensi were infected with Xc.type1 and Xc.type2 and 11.0% of Melanoides tuberculata were infected with Pc..