Some features of primary and recrudescent amodiaquine-resistant Plasmodium falciparum infections in Nigerian children

Abstract

Characteristics of primary and recrudescent Plasmodium falciparum infections were evaluated in 25 children who did not recover after amodiaquine (AQ) treatment. Recrudescence was detected by a thick blood smear and confirmed by polymerase chain reaction. Over half of recrudescent events occurred after 14 days of initiation of treatment and were associated with relatively low asexual parasitaemia. We examined the gametocyte sex ratio (GSR) in these children and in age and gender-matched controls that had AQ-sensitive (AQ-S) infections (n = 50). In both AQ-S and AQ-resistant (AQ-R) infections, the GSR was female-biased pre-treatment and became male-biased

Efficacy of Artemisinin-Based Combination Treatments of Uncomplicated Falciparum Malaria in Under-Five-Year-Old Nigerian Children

“…Paired primary and post treatment samples were analyzed using parasites' polymorphic genes to distinguish recrudescence from new infections. Briefly, block 2 of merozoite surface protein-1 (MSP-1) and the block 3 of merozoite surface protein-2 (MSP-2) and region II of glutamine-rich protein (GLURP) were amplified by two rounds of polymerase chain reaction (PCR) using specific primers as previously described 12–16. Ten microliters of the nested PCR product were resolved by electrophoresis on a 2% agarose gel and sized against 100-basepair molecular mass marker (New England Biolabs, Beverly, MA).…”

Epidemiology and Infectivity of Plasmodium falciparum and Plasmodium vivax Gametocytes in Relation to Malaria Control and Elimination

“…Antimalarial treatment may be followed by an increase (442-445, 447, 465) or decrease (445,452) in the proportion of male gametocytes that may (444,445,452) or may not (465) be influenced by the type of treatment. The uncertainties are underlined by the fact that changes in sex allocation were sometimes reported within several days after the initiation of treatment (443,445,447,452), while the environmental cues for sex determination must occur 7 to 10 days before mature gametocytes are observed (343). These findings may indicate sex-specific effects of drugs on male or female gametocytes or simply reflect the difficulty in studying parasite transmission strategies in vivo in humans.…”