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Lung Parasitic Diseases

Jun 20, 2010 | By Joni Padua

Parasitic diseases are a leading cause of illness and death worldwide, especially in areas with poor sanitation. According to the World Health Organization, an estimated one in four people harbors a parasite.
The growing number of people with suppressed immune systems, such as people taking immunosuppressive drugs and those infected with the human immunodeficiency virus, or HIV, has underscored the dangers that parasitic diseases pose worldwide. These people have a greater risk of severe disease, including lung involvement.

Echinococcosis

Tapeworms from the echinococcus genus cause the disease echinococcosis, also called hydatid disease. In the May 2006 issue of the journal "Current Opinion in Pulmonary Medicine," Dr. Akin Kuzucu wrote that the most common causes of echinococcosis in humans are the worms E. granulosus and E. multilocularis. Humans acquire the parasite by ingestion of food contaminated with animal feces or by exposure to infected animals, usually dogs, cats and foxes.
Echinococcosis primarily affects the liver but can also affect the lungs, where they can pose more problems because of their ability to grow faster. Symptoms of lung involvement include chest pain and cough. Severe cases may manifest with persistent pneumonia, bloody sputum or allergic reactions. Treatment involves surgical removal of the hydatid cysts.

Paragonimiasis

Paragonimiasis is caused by Paragonimus fluke worms. Among these worms, the oriental lung fluke P. westermani causes the most number of human infections, according to the U.S. Centers for Disease Control and Prevention, or CDC. Dr. Vannan Vijayan reported in the May 2009 issue of the journal "Current Opinion in Pulmonary Medicine" that 90 percent of cases of paragonimiasis occur in Asia, where the number of infected people approaches 20 million. Human infections arise with ingestion of raw or undercooked shellfish, such as crabs and crayfish, which harbor the parasite.
Paragonimus flukes mature in the lungs. Symptoms include chest pain, chronic cough, bloody sputum and X-ray abnormalities. Kuzucu states that paragonimiasis can resemble other diseases, such as tuberculosis and lung cancer. The drug of choice for treatment is praziquantel.

Strongyloidiasis

Strongyloides stercoralis, a roundworm, causes the disease strongyloidiasis. The CDC reports that this occurs in tropical, subtropical and temperate areas, including Southern areas of the United States. Infections arise when worm from contaminated soil penetrates the skin.
In healthy humans, the disease remains confined to the intestinal tract. Kuzucu wrote that hyperinfection, an overwhelming infestation that results in more severe gastrointestinal and pulmonary effects, can develop in people with compromised immune systems. Conditions that predispose to hyperinfection include steroid therapy, HIV infection, blood cancers and malnutrition. Vijayan cited cough, wheezing, bloody sputum and shortness of breath as some of the manifestations of lung involvement. Ivermectin, thiabendazole or albendazole are the drugs used for treatment.

Toxoplasmosis

Toxoplasmosis results from infection with the protozoan parasite Toxoplasma gondi. Vijayan reports that cats usually carry the parasites, and humans acquire the infection by ingestion of contaminated food and drinks.
Symptoms include flu-like syndrome, muscle pain and lymph node enlargement. According to Vijayan, lung involvement has been increasingly reported in HIV-positive patients. Patients with toxoplasma pneumonia may present with fever, cough and difficulty breathing. Treatment involves a combination of pyrimethamine and sulfadiazine.

References

Article reviewed by Libby Swope Wiersema Last updated on: Jun 20, 2010

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