Plasmodium Mixed Infections Research Articles

IgG reactivities against recombinant Rhoptry-Associated Protein-1 (rRAP-1) are associated with mixed Plasmodium infections and protection against disease in Tanzanian children.

A cross-sectional sero-epidemiological study was performed in Magoda, Tanzania, an area where malaria is holoendemic. Blood samples were collected from children (1-4 years) and tested for IgG antibody reactivity against 2 recombinant protein fragments of Plasmodium falciparum Rhoptry-Associated Protein-1 (rRAP-1). The data were related to the prevalence of malarial disease and single P. falciparum or mixed Plasmodium infections. Fever (> or = 37.5 degrees C) in combination with parasite densities > 5000/microliter were used to distinguish between children with asymptomatic malaria infections and those with acute clinical disease. Furthermore, C-reactive protein (CRP) was applied as a surrogate marker of malaria morbidity. The prevalence of Plasmodium infections was 96.0%. Eleven children were defined as clinical malaria cases, all with single P. falciparum infections. The density of P. falciparum was significantly lower in children with mixed Plasmodium infections compared to those with single P. falciparum infections. Children with asymptomatic P. falciparum infections had higher IgG reactivities to rRAP-1, compared to IgG reactivities of children with malarial disease. Children with mixed Plasmodium infections generally showed elevated IgG reactivity to rRAP-1, when compared to children with single P. falciparum infections. The possible relationship between mixed species infections, clinical outcome of the disease and antibody responses to RAP-1 is discussed.

Splenomegaly and malaria in the central highlands of South Vietnam.

Studies on the prevalence and etiology of splenomegaly were accomplished at three hamlets of a geographically remote village in South Vietnam. The percent of children and adolescents with enlarged spleen ranged from 70 to 90. Several with Class 4 or 5 spleen enlargement were observed. Single or mixed malaria infections were demonstrated in 19 of 42 splenomegalic children. In contrast to previous highland surveys. Plasmodium malariae infections were found in five. Thirty-three of these children, chosen without regard to spleen size, were selected for further study at base camp. Microhematocrit values ranged from 30 to 44%, and five of the 33 children had anemia secondary to iron deficiency. Some of the nonanemic children exhibited hematologic abnormalities that included target cells and bone-marrow erythrohyperplasia. Parasitologic studies for leishmaniasis were negative, although five of 25 children had positive fluorescent-antibody tests for Leishmania donovani antibody. Comparison of malaria complement-fixation (CF) tests and blood-film examinations were made in 16 children. Positive reactions were demonstrated in 15, whereas only seven had demonstrable parasitemia. Moreover, the CF tests indicated mixed Plasmodium infections in 11 children, compared with only two mixed infections demonstrated by blood-film examinations. The results indicated that malaria infections were the primary cause for splenomegaly in those examined, although the beta-thalassemia trait was not excluded as a contributory factor.