Stellantchasmus falcatus

Stellantchasmus falcatus

<p align="CENTER"><span style="color: #000000;"><span style="font-size: large;"><i><b>Stellantchasmus falcatus</b></i></span></span><span style="color: #000000;"><span style="font-size: large;"><b> Onji &amp; Nishio, 1916</b></span></span></p> <p align="CENTER"><span style="color: #000000;"><span style="font-size: large;"><b>(Figure 2-24)</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>Stella = </i></span></span><span style="color: #000000;"><span style="font-size: medium;">star</span></span><span style="color: #000000;"><span style="font-size: medium;"><i>, ant</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> = against and </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>chasmus</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> = hollow along with </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>falcatus</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> = hooked</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>Diorchitrema pseudocirrata</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> Witenberg, 1929; </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Stellantchasmus formosanus</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> Katsuta, 1931; </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Stellantchasmus amplicaecalis</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> Katsuta, 1932; and </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Haplorchis pumilio</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> of Odening, 1962.</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 cats that were experimentally infected by the feeding of fish containing metacercariae (Onji and Nishio, 1916). This trematode has since been recovered from naturally infected cats and other hosts.</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;"> This trematode has been reported from Japan, Hawaii, China, the Philippines, Israel, Egypt, and Australia (Pearson, 1964).</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, mainly 6 to 18 inches from the junction with the stomach.</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;"><i>Stellantchasmus</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> specimens differ from those of </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Haplorchis</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>Procerovum</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> in that they possess two testes and possess an expulsor as in </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Procerovum</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;"> This small pyriform trematode is 0.43 to 0.55 mm long and 0.19 to 0.34 mm wide. The eggs are 21 to 23 µm long by 12 to 13 µm wide.</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 has elucidated by Martin (1958), Noda (1959), and Pearson (1960). The snail hosts include species of </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Stenomelania</i></span></span><span style="color: #000000;"><span style="font-size: medium;">, </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Melanoides</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>Tarebia</i></span></span><span style="color: #000000;"><span style="font-size: medium;">. Fish that have been found to be infected include brackish and fresh-water fish, </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Mugil</i></span></span><span style="color: #000000;"><span style="font-size: medium;">, </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Gavia</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>Anabas</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> spp; the larvae are found mainly within the skeletal muscle (Martin, 1958). The fully developed cysts are about 0.3 mm in diameter.</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;"> Not reported but thought to be asymptomatic.</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, but not reported.</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. The normal natural hosts include cats, nankeen night herons (</span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Nycticorax caledonicus</i></span></span><span style="color: #000000;"><span style="font-size: medium;">) and a whistling eagle (</span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Haliastur sphenurus</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>HAZARD TO OTHER ANIMALS:</b></span></span><span style="color: #000000;"><span style="font-size: medium;"> None known; 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 have been infected with this species in Hawaii.</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;">Martin WE. 1958. The life histories of some Hawaiian Heterophyid trematodes. J Parasitol 44:305-323.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;">Noda K. 1959. THe larval development of Stellantchasmus </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>falcatus</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> (Trematoda: Heterophyidae) in the first intermediate host. J Parasitol 45:635-642.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;">Pearson JC. 1960. New records of trematodes from the cat. Aust Vet J 36:93.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;">Pearson JC. 1964. A revision of the subfamily Haplorchiinae Looss, 1899 (Trematoda: Heterophyidae). Parasitology 54:601-676.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"><b>Figure 2-24.</b></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Stellantchasmus falcatus</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> from the small intestine of a domestic cat in Hawaii.</span></span></p>