attached
Parasitism leads to severe economic losses to marine fish exports in Sri Lanka. Swordfish is a seasonal
species with high demand both locally and internationally. Presence of a parasite in their flesh confuses the suppliers
with zoonotic Anisarkis spp. This study is aimed to identify the plerecercoid parasitic larvae found in swordfish and
establish a feasible method of diagnosis at fish processing factories. Parasites buried in frozen swordfish (Xiphias
gladius) muscles were isolated and stored in cold sea water. Samples were washed with normal saline water and
observed under bright field light microscope at 40x and 100x magnifications, and the parasites were identified based
on their morphological features. For further confirmation, confocalmicroscope was used to record scolex parameters.
Total length of the parasites was 1.7 cm– 3.5 cm (2.27 cm). Presence of the elongated, acraspidote scolex (length
6.23 mm, width at pars bothridialis 2.4 mm) with four tentacular armature and curved, apically inverted, thick
edged bothridia confirmed the parasitic larvae belonged to the Order Trypanorhyncha. Corona of falciform hooks in
the basal armature and the heteromorphous hooks in a half spiral arrangement at metabasal armature are
characteristics of the genus Molicola. This is the first record of the Trypanorhynch plerocercoid larvae
(genus:Molicola) isolated in swordfishes from Sri Lanka. This study emphasizes that morphological examination of
the parasite scolex using bright field microscopy will be helpful to distinguish the parasitic genera and feasible to
use in the fish processing factories.
