Malaria in Nicaragua

 

The CDC reports that malaria is present in only 6 of the 17 departments (sort of provinces) of Nicaragua. The 6 reported departments are located on both the Pacific and Atlantic coasts and in the interior. The absence of reports in the other 11 departments must be a reporting anomaly. Mosquitos do not acknowledge borders.

Malaria in Nicaragua is due to Plasmodium vivax in 95% of cases and Plasmodium falciparum in the remaining 5%. This is good news because P vivax is still chloroquine sensitive and children with P vivax infection have a good prognosis for full recovery, compared to P falciparum infection, which is a much more serious.

The anopheles mosquito transmits malaria. The bite transfers asexual parasite forms into the bloodstream and these parasites undergo a liver and then a red blood cell stage. About a week or two after entering the red blood cells, the blood cells burst and release thousands of parasites and inflammatory chemicals into the blood. The inflammatory chemicals include pyrogens, which cause the fever. The fever in P vivax develops every 48 hours days, which is referred to as tertian malaria. The red blood cell destruction results in anemia.

Children suffer the most severe disease, 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. Survivors develop partial immunity.

Older children might present with the classic periodic fever with chills and shivering. However, this is uncommon in young children. After the mosquito bite, younger children are asymptomatic for one or two weeks. The fever is usually continuous and might be very high (40°C) from the first day. The symptoms are non-specific. Children become restless, drowsy, apathetic, and anorexic. Older children might report generalized ache, headache, and nausea. Many children have only flu-like respiratory symptoms, with mild cough and cold. Vomiting is very common. Mild diarrhea is also common, with dark green mucoid stools. Seizures might occur at the onset of the disease. Differentiating a febrile seizure from cerebral malaria is often difficult. The liver might be slightly tender. Splenomegaly takes many days, especially in the first attack in nonimmune children. Children with partial immunity might develop only a low-grade fever, anemia, poor appetite, and malaise. The diagnosis is established when parasites are noted on a thick blood smear, but only 50% of children with malaria have a positive smear, even on repeated examination. P vivax malaria might relapse for up to 3 years.

Since the symptoms are often nonspecific, high fever in a susceptible young child requires a high index of suspicion, and in the absence of a recognized cause for the fever, empirical treatment might be necessary.

The treatment of P vivax infection is a 3-day course of chloroquine, followed by a 14-day course of primaquine. The primaquine is necessary to eliminate the dormant stage of the parasite in the liver.