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

Abstract

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.

Immune responses during gestational malaria: a review of the current knowledge and future trend of research

“…In subsequent pregnancies, as immunity against placental-adherent strains develops, there is a reduced risk of adverse effects of malaria on the mother and fetus [6] and asymptomatic parasitaemia is common [7]. In the case of vivax malaria, with increasing reports of severe cases in Asia and South America [8,9], the consequences of infection during pregnancy remain to be elucidated, although adherence to endothelial cells [10] and sequestration of infected red blood cells in deep vasculature have been recently demonstrated [11,12].…”

Retinal Hemorrhages in Severe Non-cerebral Plasmodium vivax Malaria in an Adult

“…In Plasmodium vivax malaria the mechanisms of development of retinal hemorrhage and severe diseases are not well defined. In vivo Plasmodium vivax infected RBCs are known to cause cytoadherence on human lining endothelial cells and placental tissue, though this phenomenon is lower than that with Plasmodium falciparum infected RBC [13]. Apart from these, accompanied thrombocytopenia and anaemia may be responsible for retinal hemorrhage as a confounding or even a sole cause.…”

Malaria in the State of Amazonas: a typical Brazilian tropical disease influenced by waves of economic development

“…It is likely that the introduction of Coartem® in Manaus and other municipalities in its vicinity also contributed to the decrease in P. falciparum prevalence in the state. Conversely, an increase in the number of severe cases of Plasmodium vivax malaria was recently reported, which could be associated with the decompensation of acute and/or chronic comorbidities by malaria (28) (29) . Nevertheless, the overall fatality rate from malaria continues to decrease.…”

“…However, potential hemolysis in patients with glucose-6-phosphate dehydrogenase defi ciency (G6PDd) must be considered in the administration of this drug. In the State of Amazonas, G6PDd prevalence was estimated at 4.5% (38) , and fatal cases have been reported among patients with vivax malaria treated with primaquine (28) . Introduction of tafenoquine as an anti-hypnozoite drug in the PNCM could be an important tool in the future goal of eliminating malaria, and tafenoquine use should stimulate the systematic screening of G6PDd using a rapid point-of-care testing system, although this screening still lacks accuracy and economical evaluation.…”