Hysterothylacium amoyense in Platycephalous indicus: a Persian Gulf fish and its experimental infection of mouse model

Abstract

Anisakids belong to a genus of parasitic nematodes with a life cycle involving fish and marine mammals. They cause anisakidosis (anisakiasis) by accidental ingestion of larval stage (Anisakis and other Anisakids), causing both gastrointestinal and allergic reaction in human. The aim of the current study was to report the finding of Hysterothylacium amoyense in Platycephalous indicus fishes and also its probable pathologic effect on a mouse model. In this regard, a total of 27 live third stage larvae ranging from 1.5 to 3 mm in length were collected from gut submucosa of the fish Platycephalous indicus [ZAMIN KAN] and washed up by saline 6 %, and two were characterized as Hysterothylacium amoyense by morphologic and molecular techniques. A total of 25 larvae were orally fed to 5 inbred mice (each 5). A total of 5 mice were also selected as control group; they did not receive the larvae. After 2 weeks, all mice were necropsied using ethical protocol of SUMS. Their specimens, both gross and histologic, were observed and described. Tumor-like nodules were observed in 3 out of 5 infected mice group which could be misdiagnosed as cancer. Microscopic examinations showed lymphocytic infiltration. No pathologic changes were found in the control group. The results showed an invasive anisakid, Hysterthylacium amoyense, with histopathologic features observed in the mammal model (mouse). The parasite has been found in benthic fish Platycephalous indicus in the Persian Gulf, Bushehr region, southern Iran. The parasite could be regarded as a possible source of anisakidosis in coastal populations and should be regarded as a public health problem.