Apophallus venustus

Apophallus venustus

<p align="CENTER"><span style="color: #000000;"><span style="font-size: large;"><i><b>Apophallus venustus</b></i></span></span><span style="color: #000000;"><span style="font-size: large;"><b> (Ransom, 1921) Cameron, 1936</b></span></span></p> <p align="CENTER"><span style="color: #000000;"><span style="font-size: large;">(Figure 2-15)</span></span></p> <p align="JUSTIFY"></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>Apo</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> (away from) + </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>phallus</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> (phallus) [the genital opening is anterior to the ventral sucker] and </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>venustus</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> (=handsome, comely in appearance)</span></span></p> <p align="JUSTIFY"></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>Cotylophallus venustus</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> Ransom, 1920; </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Tocotrema donicum</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> (Skrjabin and Lindtrop, 1919) Witenberg, 1929; </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Apophallus donicus</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> (Skrjabin and Lindtrop, 1919) Price, 1931; </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Rossicotrema venustus</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> (Ransom, 1921) Ciurea, 1933.</span></span></p> <p align="JUSTIFY"></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;"> Cameron (1936) considered </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Apophallus venustus</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> a species distinct from its European counterpart </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Apophallus donicus</i></span></span><span style="color: #000000;"><span style="font-size: medium;">. The morphological distinctions that he noted were anterior extent of the vitellaria (to the esophageal bifurcation in </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Apophallus venustus</i></span></span><span style="color: #000000;"><span style="font-size: medium;">, to the ventral sucker in </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Apophallus donicus</i></span></span><span style="color: #000000;"><span style="font-size: medium;">), </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Apophallus</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>venustus</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> being slightly longer and having eggs that are slightly larger. </span></span></p> <p align="JUSTIFY"></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;"> North America, mainly eastern North America. The Alaskan fox from which it was originally described was from the National Park Zoo in Washington DC. The original description also included specimens collected from a cat in the Washington D.C. area (Ransom, 1920.</span></span></p> <p align="JUSTIFY"></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"></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;"> This worm is small, less than 1.44 mm in length, but typically slightly larger than </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Apophallus donicus</i></span></span><span style="color: #000000;"><span style="font-size: medium;">. The ventral sucker is small, the large, globular testes are located obliquely in the posterior of the body, and the vitellaria extend anterior to the ventral sucker, often to the level of the esophageal bifurcation.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"> The eggs are 26 to 32 µm long by 18 to 22 µm in width.</span></span></p> <p align="JUSTIFY"></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 was examined by Cameron (1937). The snail, </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Goniobasis livescens</i></span></span><span style="color: #000000;"><span style="font-size: medium;">, becomes infected by ingesting the embryonated egg from which the miracidium then hatches. From the stages in the snail, cercariae are produced that have long, unbranched tails, with flanges, and pigmented eyespots. These cercariae penetrate the skin of fish, and then produce metacercariae in the musculature. Cats become infected by ingesting the infected fresh-water fish, e.g., catfish and sunfish. The prepatent period appears to be one to three weeks, and the adult flukes appear to live only a few months.</span></span></p> <p align="JUSTIFY"></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;"> Thought to be asymptomatic even though the parasite becomes embedded in the mucosa of the ilium.</span></span></p> <p align="JUSTIFY"></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"></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. Animals other than the cat that have been shown to serve as hosts of the adult fluke include the dog, raccoon (</span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Procyon lotor</i></span></span><span style="color: #000000;"><span style="font-size: medium;">), Alaskan fox (</span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Vulpes lagopus</i></span></span><span style="color: #000000;"><span style="font-size: medium;">), harbor seal (</span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Phoca vitulin</i></span></span><span style="color: #000000;"><span style="font-size: medium;">), and the great blue heron (</span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Ardea herodias</i></span></span><span style="color: #000000;"><span style="font-size: medium;">).</span></span></p> <p align="JUSTIFY"></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. Although other hosts are infected, the major means of infection is through the ingestion of the fish intermediate host which requires that the appropriate snail also be available. Thus, infection of these other hosts will typically only occur in the wild.</span></span></p> <p align="JUSTIFY"></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;"> None. Humans theoretically could become infected if they ingested an infected piscine host.</span></span></p> <p align="JUSTIFY"></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;"> Prevention of the ingestion of raw fish.</span></span></p> <p align="JUSTIFY"></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;">Cameron TWM. 1936. Studies on the heterophyid trematode, </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Apophallus</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>venustus</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> (Ransom, 1920) in Canada. Part I. Morphology and taxonomy. Can J Res 14:59-69.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;">Cameron TWM. 1937. Studies on the heterophyid trematode </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Apophallus</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>venustus</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> (Ransom, 1920) in Canada. Part II. Life history and bionomics. Can J Res 15:38-51.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;">Ransom BH. 1920. Synopsis of the trematode family Heterophyidae with descriptions of a new genus and five new species. Proc U.S. Nat Mus 57:527-573.</span></span></p>