Heterophyopsis continua

Heterophyopsis continua

<p align="CENTER"><span style="color: #000000;"><span style="font-size: large;"><i><b>Heterophyopsis continua</b></i></span></span><span style="color: #000000;"><span style="font-size: large;"><b> (Onji &amp; Nishi, 1916) Tubangui &amp; Africa, 1938</b></span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"><b>ETYMOLOGY:</b></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Hetero</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> = different and </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>phyopsis</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> = late form (referring to the position of the testes being behind each other) along with </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>continua</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> = continuous referring to the expanded nature of the uterus.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"><b>SYNONYMS:</b></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Heterophyes continua</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> Onji &amp; Nishi, 1916; </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Heterophyes</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>expectans</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> Africa &amp; Garcia, 1935, </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Pseudoheterophyes</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>continua</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>major</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> in a new genus created by Yamaguti (1939).</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"><b>HISTORY:</b></span></span><span style="color: #000000;"><span style="font-size: medium;"> This species was originally described from a naturally infected tern, </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Colymbus arcticus pacificus</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> in Japan. It was also collected from a cat that was experimentally infected by the feeding of the infected tissue of a fish, </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Mugil cephalus</i></span></span><span style="color: #000000;"><span style="font-size: medium;">.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"><b>GEOGRAPHIC DISTRIBUTION:</b></span></span><span style="color: #000000;"><span style="font-size: medium;"> Cats in Japan and Korea (Eom</span></span><span style="color: #000000;"><span style="font-size: medium;"><i> et al</i></span></span><span style="color: #000000;"><span style="font-size: medium;">., 1985) and in the Philippines (Tubangui and Africa, 1938).</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"><b>LOCATION IN HOST:</b></span></span><span style="color: #000000;"><span style="font-size: medium;"> Small intestine.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"><b>PARASITE IDENTIFICATION:</b></span></span><span style="color: #000000;"><span style="font-size: medium;"> Specimens of </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Heterophyopsis continua</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> differ from species of </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Heterophyes</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> in that the testis of </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Heterophyopsis</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> spp. are tandem, i.e., one in front of the other, rather than being beside each other as in </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Heterophyes</i></span></span><span style="color: #000000;"><span style="font-size: medium;">. The flukes collected from Korean cats measure 1.8 to 2.3 mm in length and 0.26 to 0.28 mm in width. The eggs are 25 x 15 µm.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"><b>LIFE CYCLE:</b></span></span><span style="color: #000000;"><span style="font-size: medium;"> The life cycle involves metacercariae encysted in the brackish-water fish, </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Mugil, Lateolabrax</i></span></span><span style="color: #000000;"><span style="font-size: medium;">, </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Acanthogobius</i></span></span><span style="color: #000000;"><span style="font-size: medium;">, and </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Clupanodon</i></span></span><span style="color: #000000;"><span style="font-size: medium;">. Cats become infected by the ingestion of these fish where the metacercariae are encysted within the musculature.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"><b>CLINICAL PRESENTATION AND PATHOGENESIS:</b></span></span><span style="color: #000000;"><span style="font-size: medium;"> Signs in cats have not been reported. Signs have been reported with humans infected with these trematodes, but they were also hosts to other parasitic helminths which confuses the assignment of signs specifically to this parasite.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"><b>TREATMENT:</b></span></span><span style="color: #000000;"><span style="font-size: medium;"> Probably praziquantel. Praziquantel (15 mg/kg followed by the administration of a purgative 30 g of magnesium sulfate in order to collect the worms) has been used successfully in the treatment of humans infected with this trematode (Seo</span></span><span style="color: #000000;"><span style="font-size: medium;"><i> et al</i></span></span><span style="color: #000000;"><span style="font-size: medium;">., 1984).</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"><b>EPIZOOTIOLOGY: </b></span></span><span style="color: #000000;"><span style="font-size: medium;"> Cats become infected by eating raw fish. Other hosts that ingest infected raw fish are also likely to become infected, although it would appear that the rat is not a susceptible host.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"><b>HAZARD TO OTHER ANIMALS:</b></span></span><span style="color: #000000;"><span style="font-size: medium;"> Dogs and other animals have been infected; however, due to the requirements for two intermediate hosts, it is unlikely that an infected cat would pose a direct threat to other animals.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"><b>HAZARD TO HUMANS:</b></span></span><span style="color: #000000;"><span style="font-size: medium;"> Humans in Japan and along the southern coast of Korea have been infected with this parasite by the ingestion of metacercariae in brackish water fish (Seo</span></span><span style="color: #000000;"><span style="font-size: medium;"><i> et al</i></span></span><span style="color: #000000;"><span style="font-size: medium;">., 1984). </span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"><b>CONTROL/PREVENTION:</b></span></span><span style="color: #000000;"><span style="font-size: medium;"> The prevention of the ingestion of raw fish.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"><b>REFERENCES:</b></span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;">Eom ES, Son SY, Lee JS, Rim HJ. 1985. Heterophyid trematodes (</span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Heterophyopsis</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>continua</i></span></span><span style="color: #000000;"><span style="font-size: medium;">, </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Pygidiopsis</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>summa</i></span></span><span style="color: #000000;"><span style="font-size: medium;">, and </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Heterophyes</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>heterophyes</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>nocens</i></span></span><span style="color: #000000;"><span style="font-size: medium;">) from domestic cats in Korea. Korean J Parasitol 23:197-202.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;">Tubangui MA, Africa CM. 1938. The systematic position of some trematodes reported from the Philippines. Philip J Sci:117-127.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;">Seo BY, Lee SH, Chai JY, Hong SJ. 1984. Studies on intestinal trematodes in Korea. XIII. Two cases of natural human infection by </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Heterophyopsis</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>continua</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> and the status of metacercarial infection in brackish water fishes. Korean J Parasitol 22:51-60.</span></span></p>