Parasites Infecting the Respiratory Tract

Parasitic infections of the respiratory tract occur worldwide among both immunocompetent and immunocompromised patients. Parasites of the respiratory system could be responsible for many chronic and debilitating diseases including the following: bronchial asthma and allergic rhinitis caused by the house dust mites (HDM); transient pulmonary infiltrate (Loffler’s syndrome/parasitic pneumonia), manifested during infection with Ascaris, hookworms (Ancylostoma duodenale, Necator americanus), S. stercoralis and Toxocara; cystic and coin lung lesions seen during infection with hydatid cysts, amebic lung abscess and Dirofilaria immitis; lung consolidation and pleural effusion caused by Paragonimus westermani infection. Additionally, tropical pulmonary eosinophilia is caused by Wuchereria bancrofti and Brugia species. Parasites of the respiratory tract could be one of the following: parasites inhabiting the lung, e.g., Paragonimus westermani; or parasites carried to the lung, e.g., Echinococcus granulosus (hydatid cysts), Entamoeba histolytica (amebic lung abscess); or parasites passing through the lung during their normal development, e.g., Ascaris, hookworms, S. stercoralis, Wuchereria bancrofti, and Brugia malayi. Or they could be ectopic parasitic stages that accidentally infect the lung, e.g., Toxocara cati, Toxocara canis, and Dirofilaria immitis.