Alaria marcianae

Alaria marcianae

<p align="CENTER"><span style="color: #000000;"><span style="font-size: large;"><i><b>Alaria</b></i></span></span><span style="color: #000000;"><span style="font-size: large;"><i><b>marcianae</b></i></span></span><span style="color: #000000;"><span style="font-size: large;"><b> (La Rue, 1917) Walton, 1949</b></span></span></p> <p align="CENTER"><span style="color: #000000;"><span style="font-size: large;">(Figs. 2-4 to 2-7)</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>Alaria</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> (winged - referring to the alate nature of the forebody) and </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>marcianae</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> for the specific name of the garter snake, </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Thamnophis</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>marcianus</i></span></span><span style="color: #000000;"><span style="font-size: medium;">, from which the mesocercarial stage was first recovered by La Rue (1917).</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>Cercaria marcianae</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> La Rue, 1917; </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Agamodistomum marcianae</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> (La Rue, 1917) Cort, 1918.</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 first collected as a larval form, the mesocercaria, from the tissues of the garter snake and described as </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Cercaria</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>marcianae</i></span></span><span style="color: #000000;"><span style="font-size: medium;">. It was later demonstrated that the larval stage was present in frogs and that snakes may serve as paratenic hosts (Cort, 1918). The sporocyst and cercarial stages were described from naturally infected snails and the cercariae shown to be capable of developing in tadpoles by Cort and Brooks (1928). Cuckler (1941) recovered adult worms from cats fed mesocercariae from naturally infected frogs. Burrows and Lillis (1965) described the adult form for the first time from naturally infected cats.</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;"> North America.</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;"> These are very small trematodes that are 1.2 to 1.6 mm long with a distinct forebody and hindbody (Figs 2-4 and 2-5). On each side of the small oral sucker are two anteriorly directed tentacles associated with pseudosuckers that are about 100 µm long. The oral sucker is about 100 µm wide. The forebody is concave ventrally and the lateral margins fold in and partially overlap the ventral surface of the body. The ventral sucker is about the same diameter as the oral sucker and is located in the middle of the forebody. The tribocytic organ is just posterior to the ventral sucker, and is approximate 150 to 200 µm wide and slightly more than twice as long as wide. The vitellaria are almost exclusively in the forebody. The sexual organs are located mainly in the hindbody. The posterior testis is bilobed with one lobe on each side of the body. the anterior testis appears only on one side of the body and is slightly smaller than a lobe of the posterior testis. The ovary is just anterior to the anterior testis.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"> The oval eggs are large, 110 to 127 µm long by 65 to 72 µm wide, operculate, and not embryonated when they leave the fluke (Fig. 2-6). When the eggs become embryonated after several weeks in fresh water, the miracidium has two dark eye spots (Fig. 2-7).</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 of </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Alaria</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>marcianae</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> was initially elucidated by Johnson (1968) and then expanded by Shoop and Corkum (1982 &amp; 1983). The eggs are passed in the feces of the final host in an undeveloped state. After development, the eggs contain miracidia that possess two pigmented eye spots. The miracidia then seek out a snail host of the genus </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Helisoma</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> in which they develop into sporocysts. From the sporocysts are released longifurcous cercariae that possess both oral and ventral suckers, a pharynx, unpigmented eyespots, and well developed penetration glands. The cercariae penetrate and develop in tadpoles. The stage in the tadpole is termed a mesocercaria due to its resemblance to an enlarged cercarial body without the tail. Mesocercariae are capable of being passed between carnivorous paratenic hosts. When the mesocercaria is ingested by the final host, the mesocercariae typically migrate through the lungs where they develop through the metacercarial stage before returning to the intestine where they develop to adults. Eggs are produced in the feces of cats 19 days after infection. The work of Shoop and Corkum showed that it is possible for mesocercariae to be transmitted between mammalian paratenic hosts by transmammary transmission. Also, if queens become infected with mesocercariae while nursing they can pass the infection onto their offspring through the milk.</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;"> There are no reports of </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Alaria</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>marcianae</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> causing clinical disease in cats. However, the migration through the lung could cause migrating tracts through the lung parenchyma. </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 frogs, reptiles, or small mammals and birds that contain mesocercariae in their tissues. It is also possible for kittens to become infected through the milk of the queen. Other hosts of </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Alaria marcianae</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> include the opossum, </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Didelphis virginiana</i></span></span><span style="color: #000000;"><span style="font-size: medium;">, 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;">, striped skunk, </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Mephitis mephitis</i></span></span><span style="color: #000000;"><span style="font-size: medium;">, spotted skunk, </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Spiglogale putrorius</i></span></span><span style="color: #000000;"><span style="font-size: medium;">, red fox, </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Vulpes fulva</i></span></span><span style="color: #000000;"><span style="font-size: medium;">, gray fox, </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Urocyon cinereoargeteus</i></span></span><span style="color: #000000;"><span style="font-size: medium;">, and the dog.</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. Although other hosts are infected, the major means of infection is through the ingestion of the intermediate host which requires that the appropriate snail also be available.</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;"> There have been reports of </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Alaria</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> causing disease in humans. The first report was a single worm in the eye of a woman from Ontario, Canada (Shea </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;">., 1973); it was believed that the woman may have been infected by rubbing her eyes while cleaning frog legs for cooking. The second case was fatal (Fernandes </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;">., 1976; Freeman </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;">., 1976) and also occurred in Ontario. In this case, numerous mesocercariae were recovered from a patient who was suffering from severe respiratory distress who ultimately died. The mesocercariae in this case were identified as those of </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Alaria americana</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> (= </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Alaria canis</i></span></span><span style="color: #000000;"><span style="font-size: medium;">). It was never determined how the man became infected although it is suspected that he may have eaten raw or undercooked frog legs. The third case involved two intradermal swellings in the thigh and iliac crest of a man in Louisiana (Beaver </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;">., 1977). In this case, the mesocercaria has been stated to be similar if not identical to that of </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Alaria marcianae</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> (Shoop and Corkum, 1981). It is believed that his man may have become infected by the ingestion of undercooked game, perhaps a raccoon.</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;"> With cats that hunt, it will be very difficult to prevent infection with this parasite.</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;">Beaver PC, Little MD, Tucker CF, Reed RJ. 1977. Mesocercaria in the skin of man in Louisiana. AM J Trop Med Hyg 26:422-426.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;">Cort WW. 1918. The excretory system of </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Agamodistomum</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>marcianae</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> (La Rue), the agamodistome stage of a fork-tailed cercaria. J Parasitol 4:130-134.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;">Cort WW, Brooks ST. 1928. Studies on the holostome cercariae form Douglas Lake Michigan. Tr Am Micr soc 47:179-221.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;">Cuckler AC. 1941. Morphological and biological studies on certain strigeid trematodes of mammals. PhD Thesis University of Minnesota, Minneapolis, Minn. 102 pages.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;">Fernandes BJ, Cooper JD, Cullen JB, Freeman RS, Ritchie AC, Scott AA, Stuart PF. 1976. System infection with </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Alaria</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>americana</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> (Trematoda). CMA Journal 115:1111-1114.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;">Freeman RS, Stuyart PF, Cullen JB, Ritchie AS, Mildon A, Fernandes BJ, Bonin R. 1976. Fatal human infection with mesocercariae of the trematode </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Alaria</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>americana</i></span></span><span style="color: #000000;"><span style="font-size: medium;">. Am J Trop Med Hyg 25:803-807.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;">Johnson AD. 1968. Life history of </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Alaria</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>marcianae</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> (La Rue, 1917) Walton, 1949 (Trematode: Diplostomatidae). J Parasitol 54:324-332.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;">La Rue GR. 1917. Two new larval trematodes from </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Thamnophis</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>marciana</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>Thamnophis</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>eques</i></span></span><span style="color: #000000;"><span style="font-size: medium;">. Occa Papers Mus Zool Univ Michigan. 35:1-12.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;">Shea M, Maberley AL, Walters J, Freeman RS, Fallis AM. 1973. Intraretinal larval trematode. Tr Am Acad Ophth Otol. 77:784-791.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;">Shoop WL, Corkum KC. 1981. Epidemiology of </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Alaria</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>marcianae</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> mesocercariae in Louisiana. J Parasitol 67:928-931.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;">Shoop WL, corkum KC. 1982. Transmammary infection of newborn by larval trematodes. Science 223:1082-1083.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;">Shoop WL, corkum KC. 1983. Transmammary infection of paratenic and definitive hosts with </span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Alaria</i></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>marcianae</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> (Trematodea) mesocercariae. J Parasitol. 69:731-735.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"><b>Figure 2-4. </b></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Alaria marcianae</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> adult showing the alate tentacles associated with the pseudosucker on either side of the head and the division of the body into distinct forebody and hindbody sections.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"><b>Figure 2-5.</b></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Alaria marcianae </i></span></span><span style="color: #000000;"><span style="font-size: medium;">adult showing how the alae are not always obvious on the anterior end. In the center of the body between the junctions of the fore and hind body can be observed the tribocytic organ.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"><b>Figure 2-6.</b></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Alaria marcianae</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> egg as it appears when passed in the feces.</span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-size: medium;"><b>Figure 2-7.</b></span></span><span style="color: #000000;"><span style="font-size: medium;"><i>Alaria marcianae</i></span></span><span style="color: #000000;"><span style="font-size: medium;"> egg containing a developed miracidium with dark pigmented eyespots.</span></span></p>