Paragonimus

Genus of flukes
Automatic taxobox
| image = Paragonimus westermani 01. jpg
| image caption = Egg of Paragonimus westermani
| display parents = 3
| parent authority = Dollfus, 1939
| taxon = Paragonimus
| authority = Braun, 1899
| subdivision =
Paragonimus africanus
Paragonimus caliensis
Paragonimus compactus
Paragonimus ecuadoriensis
Paragonimus heterotremus
Paragonimus hueitugensis
Paragonimus ichunensis
Paragonimus iloktsuenensis
Paragonimus kellicotti
Paragonimus mexicanus
Paragonimus miyazakii
Paragonimus ohirai
Paragonimus pulmonalis
Paragonimus peruvianus
Paragonimus sadoensis
Paragonimus skrjabini Several of the species are known as lung flukes. In humans some of the species occur as zoonoses; the term for the condition is paragonimiasis. The first intermediate hosts of Paragonimus include at least 54 species of freshwater snails from superfamilies Cerithioidea and Rissooidea. The most prominent species of Paragonimus in human medicine is Paragonimus westermani, an infectious lung fluke originating in eastern Asia. Worldwide, about nine species of Paragonimus are known to cause human paragonimiasis in which many of the species reside in East Asia, West Africa, and in North and South America. The adult flatworm has an oval shape body with spines covering its thick tegument. Both the oral sucker and acetabulum are round and muscular. The acetabulum is slightly bigger than the oral sucker – 0.19 mm and 0.12 mm, respectively. The domestic cat is a reservoir for a variety of lung flatworms and can transmit the infection to humans.

Symptoms of paragonimiasis may include abdominal pain, diarrhea, fever, and hives. If the infection remains untreated, the symptoms may diminish or disappear after only few months, but sometimes they last for decades. Paragonimiasis is caused by the body's natural immune response to the worms and eggs that are present and also migrating from the intestines to the lungs. As a rule, the parasites begin to cause symptoms about three weeks after ingesting live metacercariae. After about eight weeks, they begin to produce eggs in the lungs. Some patients develop brain damage if parasites establish in the brain and produce eggs. The brain damage commonly causes headache, vomiting, and seizures. Untreated cerebral paragonimaisis commonly results in death from increased intracranial pressure.

Praziquantel has been used to effectively treat paragonimiasis by separating the tegument. An effectively complete rate of cure may be expected after three days of treatment if there has not been too much permanent damage, such as from intracranial effects. Other medications can also be used such as bithionol, niclofan, and triclabendazole with high cure rates.

Thorough cooking of an infected crustacean kills all stages of the parasite. Crab meat should not be eaten raw, even if pickled, because the pickling solution often fails to kill all the parasites. Utensils and cutlery boards should be cleaned thoroughly before and after food preparation.