Factors contributing to anemia after uncomplicated falciparum malaria.

Abstract

Abstract. The factors contributing to anemia in falciparum malaria were characterized in 4,007 prospectively studied patients on the western border of Thailand. Of these, 727 patients (18%) presented with anemia (haematocrit Ͻ 30%), and 1% (55 of 5,253) required blood transfusion. The following were found to be independent risk factors for anemia at admission: age Ͻ 5 years, a palpable spleen, a palpable liver, recrudescent infections, being female, a prolonged history of illness (Ͼ 2 days) before admission, and pure Plasmodium falciparum infections rather than mixed P. falciparum and Plasmodium vivax infections. The mean maximum fractional fall in hematocrit after antimalarial treatment was 14.1% of the baseline value (95% confidence interval [CI], 13.6-14.6). This reduction was significantly greater in young children (aged Ͻ 5 years) and in patients with a prolonged illness, high parasitemia, or delayed parasite clearance. Loss of parasitized erythrocytes accounted for Ͻ 10% of overall red blood cell loss. Hematological recovery was usually complete within 6 weeks, but it was slower in patients who were anemic at admission (adjusted hazards ratio [AHR], 1.9, 95% CI, 1.5-2.3), and those whose infections recrudesced (AHR, 1.2, 95% CI, 1.01-1.5). Half the patients with treatment failure were anemic at 6 weeks compared with 19% of successfully treated patients (relative risk, 2.8, 95% CI, 2.0-3.8). Patients coinfected with P. vivax (16% of the total) were 1.8 (95% CI, 1.2-2.6) times less likely to become anemic and recovered 1.3 (95% CI, 1.0-1.5) times faster than those with P. falciparum only. Anemia is related to drug resistance and treatment failure in uncomplicated malaria. Children aged Ͻ 5 years of age were more likely than older children or adults to become anemic. Coinfection with P. vivax attenuates the anemia of falciparum malaria, presumably by modifying the severity of the infection.

Prevalence and Factors Associated with Anemia Among Children Under 5 Years of Age—Uganda, 2009

“…14 The causative role of malaria, particularly Plasmodium falciparum, in anemia is particularly important in malariaendemic regions, including much of sub-Saharan Africa (SSA). [15][16][17][18] The vast majority of people living in Uganda are at risk of malaria, and although malaria transmission is of varied intensity, as documented by the entomological inoculation rate, rates of malaria transmission in Uganda are among the highest in the world. 19 According to the WHO, 90% of the total Ugandan population reside in areas of high malaria transmission, almost exclusively via P. falciparum.…”

Influence of Anemia on Plasmodium falciparum Gametocyte Sex Ratios in Acutely Symptomatic Children

“…There are potential applications of our findings: In addition to other causes, anemia in falciparum malaria is related to antimalarial drug resistance and treatment failure [26]. Therefore, prompt treatment of acute malaria infections with effective non-anemia and non-gametocytaemia-inducing drugs such as the artemisinin derivatives [19,22,29,30] should reduce the burden of malarial anemia; community control of infections and anemia should reduce the risk of gametocyte carriage and a male biased PfGSR and burden of malaria transmission.…”

“…In natural infections in animals sex ratio often increase over the course of infections [12,25]. Since a longer duration of illness is a predictor of anemia in malaria [26], it would appear the relatively longer duration of the untreated infections in anemic children allow a faster progression of a natural change of increase in PfGSR. The lack of correlation between hematocrit and PfGSR in anemic children and the significantly negative correlation in the non-anemic children, Mean gametocyte sex ratio suggest that, in this cohort of children, the critical haematocrit threshold producing 'all or none effect' on GSR was a value below 25%.…”

Delayed Hemolysis After Parenteral Artesunate Therapy for Severe Malaria in Two Returning Canadian Travelers

“…In uncomplicated malaria, the hemoglobin nadir is usually around 1 week after treatment initiation with a rapid recovery to normal over the subsequent 3-4 weeks. 19 In our first patient, hospital discharge was delayed since the concept PADH was not recognized and the patient underwent invasive procedures in an attempt to explain his anemia. Previously, it was suggested that the absence of cases of PADH reported from North America might be explained by the differences between the artesunate products used in North America and Europe.…”