Paragonimiasis: a view from Columbia.

Paragonimiasis is a zoonosis caused by adult trematodes of the Paragonimus genus. The infection in humans is a result of a complex transmission cycle that includes two obligate intermediate hosts, a snail and a crustacean or a crayfish, and a definitive mammalian host. It has been shown that 9 of the more than 40 species of Paragonimus described affect humans in over 39 countries in Asia, Africa and America. It is estimated that 20.7 million people have paragonimiasis and it is calculated that 195 million people are at risk of being infected. The illness usually is caused once the parasite has settled in the lung at the site of the main clinical symptoms: cough, thoracic pain and hemoptysis. The diagnosis of paragonimiasis is based on the patient's history, the parasitological findings (ova in sputum and in feces), and the result of radiological and immunological tests. In severe cases, the patient may suffer from life-threatening hemoptysis or pneumothorax. Currently, praziquantel is the drug of choice.