Relative undernourishment and food insecurity associations with Plasmodium falciparum among Batwa pygmies in Uganda: evidence from a cross-sectional survey.

Although malnutrition and malaria co-occur among individuals and populations globally, effects of nutritional status on risk for parasitemia and clinical illness remain poorly understood. We investigated associations between Plasmodium falciparum infection, nutrition, and food security in a cross-sectional survey of 365 Batwa pygmies in Kanungu District, Uganda in January of 2013. We identified 4.1% parasite prevalence among individuals over 5 years old. Severe food insecurity was associated with increased risk for positive rapid immunochromatographic test outcome (adjusted relative risk [ARR] = 13.09; 95% confidence interval [95% CI] = 2.23-76.79). High age/sex-adjusted mid-upper arm circumference was associated with decreased risk for positive test among individuals who were not severely food-insecure (ARR = 0.37; 95% CI = 0.19-0.69). Within Batwa pygmy communities, where malnutrition and food insecurity are common, individuals who are particularly undernourished or severely food-insecure may have elevated risk for P. falciparum parasitemia. This finding may motivate integrated control of malaria and malnutrition in low-transmission settings.

Early interferon-gamma response against Plasmodium falciparum correlates with interethnic differences in susceptibility to parasitemia between sympatric Fulani and Dogon in Mali.

INTRODUCTION: Interethnic differences in susceptibility to malaria provide a unique opportunity to explore immunological correlates of protection. The Fulani of Sahelian Africa are known for their reduced susceptibility to Plasmodium falciparum, compared with surrounding tribes, yet the immunology underlying this is still poorly understood. METHODS AND RESULTS: Here, we show that mononuclear cells from Fulani elicit >10-fold stronger interferon (IFN)-gamma production following a 24-h in vitro coincubation with asexual parasites than cells from sympatric Dogon. This response appears to be specific for P. falciparum among a panel of other human pathogens and is independent of the lower number of regulatory T cell counts present in Fulani. IFN-gamma responses in both tribes were inversely correlated with peripheral parasite density as quantified by nucleic acid sequenced-based amplification, but responses of Fulani remained significantly stronger than those of Dogon after adjustment for concurrent parasitemia, suggesting that hard-wired immunological differences underlie the observed protection. CONCLUSIONS: These results underscore the value of early IFN-gamma responses to P. falciparum as a correlate of anti-parasite immunity, not only in this setting but also in the wider context of malaria, and support the development of malaria vaccines aimed at inducing such responses.

Malaria endemicity in an Orang Asli community in Pahang, Malaysia.

An epidemiological cross-sectional study was undertaken to determine the endemicity of malaria among the Orang Asli population of Raub, Pahang. Malaria endemicity was measured in terms of the prevalence of parasitaemia and splenomegaly. A total of 520 Orang Asli were examined. The point prevalence of malaria was 24.2% (95% CI 20.7-25.1), with Plasmodium falciparum (67.5%) being the predominant species. Children < 12 years were at least 3.7 times more likely to be parasitaemic compared to those older. The prevalence of malaria among children 2-<10 years was 38.1% (95% CI 31.6-50.0). Spleen rate among children 2-<10 years old was 22.3% (95% CI 17.1-28.3). The average enlarged spleen size was 1.2. These findings classify the study area as being mesoendemic. Malaria control activities among the Orang Asli should focus on protecting vulnerable subgroups like young children. Measuring the level of malaria endemicity at regular intervals is fundamental in evaluating the effectiveness of malaria control programs.

[Malignant tropical malaria in native Africans living in a large city]. / Zlokachestvennaia tropicheskaia maliariia u korennykh afrikantsev, zhitelei krupnogo goroda.

The clinical and laboratory features of severe Plasmodium falciparum-induced malaria were analyzed in 91 adult patients living a large African city. Within a week, 52 patients developed the disease from the manifestations of overall intoxication to the complete picture of severe malaria accompanied by coma. Fifty eight patients were found to be residents of Conakry and 54 of them left the city 2 months before the malaria attack. Eighty one patients had experienced malaria, including 38 patients had 1-2 attacks in the past year. The patients were parenterally treated with quinine in a dose of 750-850 mg of the active ingredient for 24 hours during 4.1 +/- 1.7 days at hospital. In 17 of 34 patients, parasitemia disappeared from single to 5-10 parasites and more in the field of thick drop field, in the other 17 patients it decreased from 5-10 to single parasites at recovery. Twenty four comatose patients died at days 3-8 of hospital stay, most of them had symptoms of oligoanuria. The high cost of hospitalization and specific drugs were the reasons for late referral to hospital and for the use of low daily and course doses of quinine. The necessity of reviewing the principal trends of a national malaria control programme.

Antibody responses to Plasmodium falciparum sporozoite-, liver- and blood-stage synthetic peptides in migrant and autochthonous populations in malaria endemic areas.

This study evaluates the differences in host immune responses to defined plasmodial antigens in four geographically different regions in which malaria is endemic. Sera from 527 individuals were tested for the presence of antibodies specific for three types of plasmodial antigen: liver-stage antigen (LSA-1), blood-stage antigen (SPF 70) and circumsporozoite (CS) antigen (NANP)4. The individuals taking part in the study comprised: patients with transfusional malaria due to Plasmodium falciparum or P. vivax; non-immune migrants residing in an endemic area in Rondônia; Amazonian Indians from the states of Pará (Xingu PA) and Mato Grosso (Xingu MT); people living in a hyperendemic area in Africa (Burkina-Faso); and controls that had never been to a malaria endemic area. None of the transfusional sera displayed antibodies against sporozoite or to liver stage antigen, although 80% of the P. falciparum transfusional malaria sera contained IgG antibodies against the blood-stage peptide. A low percentage of Indians from Xingu PA and of non-immune migrants displayed antibodies against liver-stage (27% and 17%) and sporozoite (11% or d 12%) peptides, although a greater frequency of antibodies against blood-stage peptide (50% and 49%) was observed in both cases. Indians from Xingu MT exhibited a greater frequency of antibodies against liver, sporozoite and blood-stage peptides (45%, 50% and 58%). Only hyperimmune African individuals exhibited higher percentages of antibodies against liver- (64%) and blood-stage antigens (87%), contrasting with a low frequency of antibodies against the CS repeat (33%). Taken together, the present data confirm that Rondonian migrants and Indians from Xingu PA constitute populations with limited exposure and immunity to P. falciparum malaria infection and conversely, Xingu MT Indians and Africans have been more exposed to malaria infection. In conclusion this study indicates that the immune response to these malaria parasite peptides can be used to assess malaria transmission in epidemiological surveys.

[Drug-resistant tropical malaria in Angola]. / Lekarstvenno-ustoichivaia tropicheskaia malariia v Angole.

Three antimalarial treatment regimens by the complete standard WHO tests were examined in 105 Plasmodium falciparum-infected patients who were nonimmune newcomers treated at the Russian hospital in Luanda in 1991-1992, 61% showed chloroquine resistance and 40% fansidar resistance. All 59 patients with high rates of parasitemia were successfully cured with quinine in combination with tetracycline. Thick, if required thin, blood smears were microscopically examined. The findings suggest that Fansidar should be a drug of first-line therapy in Angola, though in the neighbouring countries quinine continues preserving its efficacy, but there is a delayed elimination of the parasites within 7 days of initiation of the therapy, making it necessary to prolong therapy with this drug up to 10 days.