Cognitive performance of children living in endemic areas for Plasmodium vivax.

BACKGROUND: The role of repeated episodes of malaria on the cognitive development of children is a relevant issue in endemic areas since it can have a long-lasting impact on individual lifespan. The aim of the current paper was to investigate whether the history of malaria can impair the verbal and performance skills of children living in an endemic area with low transmission of Plasmodium vivax malaria. METHODS: A cross-sectional study was conducted with children living in an endemic area of P. vivax malaria in Brazilian Amazon basin. The history of episodes of malaria was used as criteria for inclusion of children in the groups. The cognitive performance was assessed by the Wechsler intelligence scale for children-III edition (WISC-III), which was applied to the participants of study by two trained psychologists. RESULTS: A total of 17 cases and 26 controls was included in the study. A significant low score of verbal quotient was found in the cases (p = 0.005), however, the performance IQ was similar in both groups (p = 0.304). The full-scale IQ was significantly lower in the cases when compared to the controls (p = 0.042). The factorials index showed significant difference only in the subtest of verbal comprehension with the lower values in the cases (p = 0.0382), compared to the controls. The perceptual organization (p = 0.363), freedom from distractability (p = 0.180) and processing speed (p = 0.132) were similar in both groups. CONCLUSIONS: Children with a history of vivax malaria has a significant impairment of verbal and full-scale quotients as well as a significant low index of verbal comprehension. These findings are likely due to the absenteeism caused by malaria and by the low parental education, which impairs an adequate response to the environmental stimulus.

Lipid parameters in a hyperendemic area for malaria.

BACKGROUND: This is a cross-sectional study with the objective to analyze lipid parameters of individuals living in Brazilian Amazon, where malaria is endemic. METHODS: The city chosen was Anajás in the state of Pará, Brazil, in Amazon region. The study analyzed lipid parameters of 46 subjects, 31 male and 15 female, aged between 20-60 years without malaria, and residents for more than five years in this city considered an area hyperendemic for disease. It was established three groups according to the number of previous episodes of malaria: group I (n = 22) one to five episodes, group II (n = 20) six to ten episodes and group III (n = 4) eleven to fifteen episodes. Total cholesterol, high density lipoprotein (HDL cholesterol), and low density lipoprotein (LDL cholesterol) were measured and was confected the thick smear for malaria of all individuals. RESULTS: The hypocholesterolemia, the main characteristic of hyperendemic areas for malaria, was confirmed, but the mean of HDL cholesterol levels were 9.78% higher than the reference of World Health Organization. CONCLUSION: Although other factors might have contributed to lipid profile, the constant exposure to infection by Plasmodium, according to the physiology of the parasite, may have played an important role in defining the lipid parameters observed for this region. Further studies, such as the case-control is needed to confirm this hypothesis.

Understanding the clinical spectrum of complicated Plasmodium vivax malaria: a systematic review on the contributions of the Brazilian literature.

The resurgence of the malaria eradication agenda and the increasing number of severe manifestation reports has contributed to a renewed interested in the Plasmodium vivax infection. It is the most geographically widespread parasite causing human malaria, with around 2.85 billion people living under risk of infection. The Brazilian Amazon region reports more than 50% of the malaria cases in Latin America and since 1990 there is a marked predominance of this species, responsible for 85% of cases in 2009. However, only a few complicated cases of P. vivax have been reported from this region. A systematic review of the Brazilian indexed and non-indexed literature on complicated cases of vivax malaria was performed including published articles, masters' dissertations, doctoral theses and national congresses' abstracts. The following information was retrieved: patient characteristics (demographic, presence of co-morbidities and, whenever possible, associated genetic disorders); description of each major clinical manifestation. As a result, 27 articles, 28 abstracts from scientific events' annals and 13 theses/dissertations were found, only after 1987. Most of the reported information was described in small case series and case reports of patients from all the Amazonian states, and also in travellers from Brazilian non-endemic areas. The more relevant clinical complications were anaemia, thrombocytopaenia, jaundice and acute respiratory distress syndrome, present in all age groups, in addition to other more rare clinical pictures. Complications in pregnant women were also reported. Acute and chronic co-morbidities were frequent, however death was occasional. Clinical atypical cases of malaria are more frequent than published in the indexed literature, probably due to a publication bias. In the Brazilian Amazon (considered to be a low to moderate intensity area of transmission), clinical data are in accordance with the recent findings of severity described in diverse P. vivax endemic areas (especially anaemia in Southeast Asia), however in this region both children and adults are affected. Finally, gaps of knowledge and areas for future research are opportunely pointed out.

Increased interleukin-10 and interferon-γ levels in Plasmodium vivax malaria suggest a reciprocal regulation which is not altered by IL-10 gene promoter polymorphism.

BACKGROUND: In human malaria, the naturally-acquired immune response can result in either the elimination of the parasite or a persistent response mediated by cytokines that leads to immunopathology. The cytokines are responsible for all the symptoms, pathological alterations and the outcome of the infection depends on the reciprocal regulation of the pro and anti-inflammatory cytokines. IL-10 and IFN-gamma are able to mediate this process and their production can be affected by single nucleotide polymorphisms (SNPs) on gene of these cytokines. In this study, the relationship between cytokine IL-10/IFN-gamma levels, parasitaemia, and their gene polymorphisms was examined and the participation of pro-inflammatory and regulatory balance during a natural immune response in Plasmodium vivax-infected individuals was observed. METHODS: The serum levels of the cytokines IL-4, IL-12, IFN-gamma and IL-10 from 132 patients were evaluated by indirect enzyme-linked immunosorbent assays (ELISA). The polymorphism at position +874 of the IFN-gamma gene was identified by allele-specific polymerase chain reaction (ASO-PCR) method, and the polymorphism at position -1082 of the IL-10 gene was analysed by PCR-RFLP (PCR-Restriction Fragment Length Polymorphism). RESULTS: The levels of a pro- (IFN-gamma) and an anti-inflammatory cytokine (IL-10) were significantly higher in P. vivax-infected individuals as compared to healthy controls. The IFN-gamma levels in primoinfected patients were significantly higher than in patients who had suffered only one and more than one previous episode. The mutant alleles of both IFN-gamma and IL-10 genes were more frequent than the wild allele. In the case of the IFNG+874 polymorphism (IFN-gamma) the frequencies of the mutant (A) and wild (T) alleles were 70.13% and 29.87%, respectively. Similar frequencies were recorded in IL-10-1082, with the mutant (A) allele returning a frequency of 70.78%, and the wild (G) allele a frequency of 29.22%. The frequencies of the alleles associated with reduced production of both IFN-gamma and IL-10 were high, but this effect was only observed in the production of IFN-gamma. CONCLUSIONS: This study has shown evidence of reciprocal regulation of the levels of IL-10 and IFN-gamma cytokines in P. vivax malaria, which is not altered by the presence of polymorphism in the IL-10 gene.