Chloroquine treatment for uncomplicated childhood malaria in an area with drug resistance: early treatment failure aggravates anaemia

Abstract

Childhood anaemia is a major public health problem in malaria holoendemic areas. We assessed the effects of antimalarial treatment in an area with drug-resistant falciparum malaria on haemoglobin levels in small children by applying the 1996 World Health Organization in vivo method for the evaluation of standard chloroquine treatment at the community level. In Fukayosi village, coastal Tanzania, 117 children aged 5-36 months with clinical malaria episodes were treated with chloroquine syrup (25 mg/kg). Early treatment failure (ETF) occurred in 20% and late treatment failure (LTF) in 22% of cases. Age > 1 year and malnutrition were protective factors against ETF. The evidence that chloroquine treatment could not prevent an exacerbation of anaemia was (i) the fact that the fall in haemoglobin level after 72 h was significantly greater in ETF than in children with LTF and an adequate clinical response, and (ii) the absence of any haematological improvement at follow-up in children receiving chloroquine alone, even in true treatment successes. In contrast, pyrimethamine/sulfadoxine administered to treatment failures improved the haemoglobin level significantly > 21 d after treatment started (mean difference 14 g/L, 95% confidence interval 2.1-27). We conclude that, when chloroquine treatment of childhood malaria is associated with a 20% ETF rate, the haemoglobin response is unsatisfactory and there is a need to change the recommended first-line treatment.

Resistance of Plamodium falciparum to Antimalarial Drugs in Zaragoza (Antioquia, Colombia), 1998

“…On the other hand in vivo resistance to CHL was very high (67%) and concordance was (33%). Such high levels of resistance have been registered in many malarial zones of the world such as Papua New Guinea, 85% (Al Yaman et al 1996); Tanzania, 44% (Ekvall et al 1998) and Burundi Highlands, 77.8% (Di Perri et al 1998). This resistance has frequently been observed after massive intake of antimalarial medicaments for prophylaxis (WHO 1996); but this was not the case in our study.…”

Association of Plasmodium Falciparum Isolates Encoding the P. Falciparum Chloroquine Resistance Transporter Gene K76t Polymorphism With Anemia and Splenomegaly, but Not With Multiple Infections

“…Given that multiple infections are associated with young age in holoendemic settings 16,17 and since children have a higher risk of having drug-resistant malaria, 5,21 we expected the pfcrt K76T allele to be associated with both multiple infections and young age. Our data, however, showed no relevant association between the pfcrt K76T allele and multiple P. falciparum infections.…”

Hemoglobin concentration in children in a malaria holoendemic area is determined by cumulated Plasmodium falciparum parasite densities.

“…In addition, 40% of children Ͻ 18 months were affected by early chloroquine treatment failure during the five months' observation period, leading to a concomitant drop in Hb, especially following hyperparasitemia (Table 3). 29 Hence, it was predominantly the youngest children who suffered attacks of severe acute hemolytic anemia. All treatment failures received prompt second-line therapy with SP, which at follow-up compensated for the immediate loss in Hb, most likely by subsequent reduction in the asymptomatic parasitemia level and possibly clinical malaria incidence rate.…”