First Record of Cestode Parasite Larvae Belong to Order: Trypanorhyncha Isolated from Sword Fish Captured in Sri Lanka

Abstract

Parasitic infestations cause severe economic loss to the marine fish export industry in Sri Lanka. Present study is to identify the parasites found in fish in order to determine its public health importance. Parasites were isolated from sword fish (Xiphias gladius) muscles. Specimens were fixed in formalin and observed under confocal microscope. Parasites were identified based on its morphological characteristics. Total length of the parasites were 1.7 – 3.5 cm (2.27 cm), the proglottid length was 1.97 mm, elongated acraspidote scolex length was 6.23 mm and width at pars bothridialis was 2.4 mm. Length and width of the pars bulbosa were 1.12 mm and 1.17 mm respectively. Curved, apically inverted, and thick edged bothridia and four tentacular armature were characteristics of the Order Trypanorhyncha. Basal armature with corona of falciform hooks and the metabasal armature with heteromorphous hooks in a half spiral arrangement indicated the genus Molicola. This is the first record in Sri Lanka of Trypanorhynch larvae (genus: Molicola) isolated from sword fish. Marine teleost serve as intermediate hosts for Trypanorhyncha and no serious impacts on human health has observed except mild allergy to some people.