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Chapter 22

Paragonimiasis

With Dr. Jung-Gi Im and Dr.Kee-Hyun Chang

At least two species of parasites that infect humans in the Orient were first identified in Bengal tigers in the 19th century zoos of Europe, Gnathostoma species in London and Paragonimus westermani in Amsterdam (1877). The keeper of the Amsterdam zoo found permanent fame by having his name, Westerman, given to this latter parasite, which is perhaps a little unfair to the tiger! Flukes of the genus Paragonimus were first discovered in Brazil in 1850 by Diesing. In 1879, Ringer discovered the first case of human paragonimiasis when he found a lung fluke while performing an autopsy on a Portuguese patient in Formosa (Taiwan). When told of this finding in one of his former patients, Patrick Manson suspected that this fluke might be the etiology of the benign hemoptysis be encountered so often in his practice in Amoy, China. In 1880, Manson acquired some sputa from Japanese patients who had hemoptysis and showed that the "endemic hemoptysis" of Formosa and Tokyo was caused by the same parasite. In 1889, Leuckart demonstrated that the fluke found by Kerbert in 1877 in the lungs of the Bengal tiger in Amsterdam was the identical trematode, Paragonimus westermani, causing endemic hemoptysis in Formosa and Japan.

The tortuous trail needed to unravel the life cycle of this and many other parasites has involved years of patient research in many lands, and has often required the skills of many scientists. Such painstaking efforts are largely unknown to the millions of people, especially in Asia, who live in almost symbiotic relationship with these parasites, acquired (in the case of Paragonimus) because of their appetite for raw crabs and crayfish. Even Olympic athletes have been known to harbor these lung flukes, and remain relatively unaffected by them. Considering the many who are infected (an estimated 10 million people in China alone), it is only occasionally that hemoptysis or seizures demonstrate clinically the presence of paragonimiasis.

Synonyms

Paragonimiasis. Endemic hemoptysis. Parasitic hemoptysis. Manson hemoptysis. Oriental lung fluke disease. Lung distoma. Pulmonary distomiasis or distomatosis. Sp: Paragonimus de Westerman. Fr: Paragonimiose. Ger: Lungen paragonimiose.

Definition

Paragonimiasis is infection with lung flukes of the genus Paragonimus. Sixteen species of these trematodes are pathogenic to humans, principally P. westermani, P. szechuanensis (skrjabini), P. tuanshanensis (heterotremus), P. peruvianus, P. philippinensis, P. miyazakii, P. huerlungensis, P. kellicotti, P. mexicanus, P. ecuadoriensis, P. caliensis, P. amazonicus, P. africanus, P. congolensis, P. pulmonatis, and P. uterobilateralis. Most human paragonimiasis is caused by P. westermani.

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Copyright: Palmer and Reeder

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