Plasmodium Malariae - Management and Therapy

Management and Therapy

Failure to detect some P. malariae infections has led to modifications of the species-specific primers and to efforts towards the development of real-time PCR assays. The development of such an assay has included the use of generic primers that target a highly conserved region of the 18S rRNA genes of the four human-infecting species of Plasmodium. This assay was found to be highly specific and sensitive. Although serologic tests are not specific enough for diagnostic purposes, they can be used as basic epidemiologic tools. The immunofluorescent-antibody (IFA) technique can be used to measure the presence of antibodies to P. malariae.. A pattern has emerged in which an infection of short duration causes a rapidly declining immune response, but upon re-infection or recrudescence, the IFA level rises significantly and remains present for many months or years.

The increasing need to correctly identify P. malariae infection is underscored by its possible anti-malarial resistance. In a study by Müller-Stöver et al., the researchers presented three patients who were found to be infected with the parasite after taking anti-malarial medications. Given the slower pre-erythrocytic development and longer incubation period compared to the other malaria causing Plasmodium species, the researchers hypothesized that the anti-malarials may not be effective enough against the pre-erythrocytic stages of P. malariae. They thought that further development of P. malariae can occur when plasma concentrations of the anti-malarials gradually decrease after the anti-malarial medications are taken. According to Dr. William E. Collins from the Center of Disease Control (CDC), chloroquine is most commonly used for treatment and no evidence of resistance to this drug has been found. In that event, it is possible that the results from Müller-Stöver et al. provided isolated incidences.