| Paragonimus kellicotti | |
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P. kellicotti
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| Binomial name | |
| Paragonimus kellicotti Ward, 1908 | |
Paragonimus kellicotti, the North American lung fluke, is a species of trematode in the genus Paragonimus. This species of Paragonimus has an intricate life cycle, and although its name may suggest that it is only a health concern in North America, it is also prominent in Southeast Asia and China.
Paragonimus kellicotti parasites have dorsal-ventrally flattened, brown, oval shaped bodies. They are soft bodied parasites with oval and ventral suckers that are relatively similar in size. They use their ventral suckers to attach to a host. Their tegument is covered with spines, which is a characteristic that sets them appart among other paragonimus species. Lung flukes are hermaphroditic, consisting of both the female and male organs. Thus, they are able to self-fertilize.[1]
Early larval stages are found in snails and later move on to crustaceans, primarily crawfish and crabs. P. kellicotti parasites may live in fresh or salt water. Thus, they may be found within hosts of swamp, coastal, or forest areas.
Lung fluke eggs are passed through feces or soil. Eggs will then hatch into miricidium within three weeks. The miricidium will infect he primary host, snails. Within snails, the miricidium will develop into cercariae. The cercariae will eventually leave the snail and and infect the second intermediate host, crustaceans. The lung fluke will encyst wihin the tissue of crustaceans until it the crustacean is consumed by humans or other animals. Once the fluke has been ingested, enzymes within the digestion tract of the consumer will break down the parasitic cysts. The immature parasite will continue to mature within the lungs its new host, feeding on its intestine, and lay eggs. Mature lung flukes may breed year-round. P. kellicotti may like up to twenty years within a human host.
Infections of P. kellicotti affect 21 million people world-wide. However, humans rarely become infected in North America. The frequent victims of this infection in North America are small animals that feed on crayfish, such as otters, skunks, and mink. Occasionally, dogs and cats will become infected as well. If these animals are left without treatment they will eventally die. P. kellicotti is a food-borne trematode infection. Humans become infected with the parasite by eating raw or undercooked crayfish meant that contains the parasite larvae. These infections are common in sub-Saharan Africa and the Americas. After the parasite has been ingested, it will travel from the intestines until it reaches the lungs.
There are several diagnostic symptoms of a lung fluke infection. These include a cough, fever and weight loss.[2] Pleural effusions, a condition in which a surplus of fluid accumulates around the lungs, is another symptom of an infection. P. kellicotti infection may sometimes be misdiagnosedastuberculosis. However, a lung fluke infection is differentiated from tuberculosis by increased eosinophils in the blood and pleural fluid.
AP. kellicottii infection has easy treatment. Treatment consists oral medication of praziquantel over the course of to days. In severe cases though, the patient may require surgical removal of the parasite. Surgery will not grantee that all larvae will be removed.
