Sunday, December 6, 2015

Malaria in Haiti


During my review of articles published in the New England Journal of Medicine, I learned that the island of Hispaniola (Haiti and the Dominican Republic) is the only remaining foci of endemic malaria among the Caribbean islandsChildren are the worst affected, especially children aged 6 months to 5 years. In parts of the world where malaria is endemic, malaria might cause as many as 10% of all deaths in children.

Malaria is due to a protozoal blood parasite transmitted by a mosquito bite. In the Western Hemisphere Plasmodium vivax is usually the most common parasite but in Haiti, P. falciparum is common. P. falciparum can cause cerebral malaria. 

Congenital malaria due to transplacental transfer can be significant in populations of mothers who are semi-immune to malaria. The mother might have placental parasitemia, peripheral parasitemia, or both, without any fever or other clinical manifestations. Vertical transmission of this infestation can be as high as 40% and is associated with anemia in the baby. 

In endemic areas, children younger than age 5 years have repeated and often serious attacks of malaria. The survivors develop partial immunity. Thus, older children and adults often have asymptomatic parasitemia. Most deaths resulting from malaria occur in children younger than age 5 years because they do not have immunity.

Fever is usually continuous and might be very high (40°C) from the first day. Chills and sweats are common with a high fever. Vomiting is common.

The liver may be slightly tender. Splenomegaly takes many days, especially in the first attack in nonimmune children. In children from an endemic area, severe splenomegaly sometimes occurs.

Children living in an area where malaria is endemic have frequent infections and develop and maintain partial immunity. These children often develop only a low-grade fever, anemia, poor appetite, and malaise.

Prolonged malaria can cause anemia. With heavy parasitemia and large-scale destruction of red blood cells, mild jaundice and hypoglycemia might occur.

Chloroquine is the most commonly used drug, at a dose of 5 mg/kg once a week.

I did a Google Scholar search of malaria in Haiti. Below is pertinent information from recent articles.

2010 - Center for Disease Control report that P. falciparum malaria is endemic to Haiti.

2011 - During a period of 14 weeks from Nov 2010 to Feb 2011, a total of 61 cases of P. falciparum malaria were diagnosed in a Leogane clinic. The cases accounted for 47% of 130 patients with undifferentiated fever. This seems too high. There are too many causes of fever for one infection (malaria) to cause almost half the cases. The ages of the malaria patients ranged from 3 to 67 years. About 40% were younger than 16 years.

2012 - In sharp contrast to the situation in other regions of the world, P. falciparum parasites in Haiti remain susceptible to chloroquine. This study of 49 patients with P. falciparum malaria in Leogane did not find chloroquine resistance or treatment failure.

2014 - Study from Grand'Anse reported that 17.4% of hospital consultations for fever were due to malaria.

2015 - The national prevalence of malaria in febrile outpatients reported to be 0.5%. Compared to the 2011 and 2014 studies above, this seem very low. 

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