Paragonimiasis

Paragonimiasis is a major parasitic disease caused by lung flukes belonging to the genus Paragonimus, presenting a significant public health challenge in regions such as Southeast Asia, Africa, and the Americas. This genus encompasses more than 50 species, with the Paragonimus westermani complex, Paragonimus skrjabini complex, Paragonimus ohirai complex, and Paragonimus mexicanus complex being the most widely prevalent globally. Notably, the Indian subcontinent displays remarkable species diversity, featuring several documented taxa, including Paragonimus miyazakii manipurinus n. subsp., Paragonimus hueitungensis, P. skrjabini, Paragonimus heterotremus, Paragonimus compactus, and P. westermani, which are primarily found in the north-eastern regions of India. Lung flukes have a complex multihost life cycle involving turreted freshwater snails, and crabs/crayfish as their first and second intermediate hosts, respectively. While pulmonary form of paragonimiasis is most common, infection often mimics chronic tuberculosis, and symptoms can be absent or vague in mild cases. Ectopic paragonimiasis frequently involve organs such as the brain, skin, and abdomen, and other vital organs, especially in cases caused by  P. skrjabini. Accurate diagnosis requires a combination of parasitological, radiological, serological, and molecular techniques. Understanding the multifaceted nature of this disease is crucial for control, particularly in endemic areas where consumption of undercooked crabs/crayfish poses a major transmission risk. In this context, this chapter explores paragonimiasis, highlighting its various forms, public health significance, parasite resilience, clinical aspects, diagnostic challenges, and the need for alternative mitigation strategies.