Saturday, December 5, 2015

Filariasis in Haiti

My recent review of New England Journal of Medicine articles revealed that Haiti is home to 90% of the cases of filariasis in the Western Hemisphere. Filariasis is an infection with a nematode parasite and is the cause of elephantiasis, a chronic disfiguring disease. The WHO reports that filariasis is the second leading cause of permanent disability in the world after leprosy. 

The parasite is transmitted to the human host by a mosquito bite. The first stage larvae are microfilariae. Mature worms are one to five inches in length and survive for five years. 

The microfilariae cause inflammation and swelling in the lymphatic system. The blocked lymphatic channels lead to swelling in the legs, arms, testicles, vulva, and breasts. The most common nodes affected are femoral and epitrochlear. 

Filariasis is first contracted in childhood, and most individuals in endemic areas are exposed by the third or fourth decade. 

The infection can present with episodes of acute lymphadenitis with sudden fever and painful glands. The symptoms abate within a week but episodic attacks might develop. 

Hydrocele is the most common sign of infection in a male who lives in an endemic area. 

The skin over the swollen areas is abnormal with hyperkeratosis, acanthosis, loss of elastin, and fibrosis. Skin nodules and large transient areas of localized nonerythematous subcutaneous edema can develop. 

Eye lesions can lead to blindness. 

The parasite can cause allergic symptoms with itchiness and hives and the blood eosinophil count is high. 

Prevention is the best strategy because the damage is irreversible. Mass treatment with albendazole and ivermectin is a recommended intervention. 

I performed a Google Scholar review of articles published on filariasis in Haiti since 2000. I found 35 articles and pertinent information from these articles is found below. 

2003 - Adverse reactions following mass treatment with diethylcarbamazine and albendazole are common. Overall 24% had one or more adverse reactions. Most were minor (91%) and some were moderate (9%). 

2004 - Blood collected from Haitian school children aged 6 to 11 years showed that 4% of 22,365 children were positive for Wuchereria bancrofti antigen. 

2010 - After seven rounds of mass drug administration in Leogane, Haiti, the prevalence of microfilaremia was reduced to <1% from levels as high as 15.5%. Continuing transmission of filariasis seemed to be linked to rates of noncompliance. 

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