Summary We evaluated gametocyte carriage and intensities of gametocytaemia in 710 children presenting with acute, symptomatic, uncomplicated Plasmodium falciparum malaria who were treated with various antimalarial drug regimens: chloroquine (CQ); chloroquine plus chlorpheniramine, a histamine H₁ receptor antagonist that reverses CQ resistance in P. falciparum in vitro and in vivo (CQCP); chloroquine plus ketotifen, a histamine H₁ receptor antagonist that reverses CQ resistance in P. falciparum in vitro but not in vivo in the present study (CQK); chloroquine plus pyrimethamine–sulphadoxine (CQPS); amodiaquine (AQ); amodiaquine plus pyrimethamine–sulphadoxine (AQPS); and pyrimethamine–sulphadoxine (PS). On presentation, gametocyte carriage was significantly higher in CQ‐resistant (CQ‐R) than in CQ‐sensitive (CQ‐S) infections. Following CQ treatment, gametocyte carriage was significantly higher at all times after treatment and gametocyte density significantly higher on day 7 of follow‐up in children with CQ‐R than CQ‐S infections. CQ treatment of CQ‐R infections resulted in significantly higher density of gametocytaemia on day 7 compared with pre‐treatment (day 0), but similar treatment of CQ‐S infections resulted in significantly lower density of gametocytaemia on day 14 compared with day 0. Among children with CQ‐R infections, those with mild (RI) resistance carried gametocytes significantly more often than those with moderate (RII) resistance on days 5 and 7 of follow‐up (P = 0.04 and 0.01, respectively). Disposition kinetics of gametocytaemia using a non‐compartmental method showed that the half life of gametocytaemia was longer and the clearance slower in children with CQ‐R than in those with CQ‐S infections. PS treatment was associated with significantly higher gametocyte carriage at all times between days 1 and 14, and significantly higher gametocytaemias on days 7 and 14 than in the other treatment regimens. Combination of AQ with PS significantly decreased gametocyte carriage at all times between days 1 and 14 of follow‐up. Continuing use of CQ in CQ‐R infections may encourage transmission of CQ‐R infections; SP monotherapy is associated with significant gametocyte carriage and gametocytaemia and may encourage transmission of SP resistant infections as resistance to the drug increases.

The risk factors associated with gametocytaemia at presentation and after treatment with different antimalarial drug regimens were evaluated in 767 children enrolled prospectively in 5 antimalarial drug trials between July 1996 and December 2002 in a hyperendemic area of southwestern Nigeria. The children were assigned to one of 6 treatment groups: chloroquine (CQ) only; pyrimethamine-sulfadoxine (PS) only; amodiaquine (AQ) only; CQ combined with chlorpheniramine (CQCP); or PS combined with CQ (CQPS) or AQ (AQPS). At enrolment, 115 (15%) of 767 children were gametocyte carriers. During follow-up, 15·6% of all patients (i.e. 120 patients) developed patent gametocytaemia, which in 85% (102 patients) had developed by day 7 following treatment. In a multiple regression model, 4 factors were found to be independent risk factors for the presence of gametocytaemia at enrolment: male gender (adjusted odds ratio [AOR]=0·55, 95% confidence interval [CI] 0·36–0·83,P=0·005), absence of fever (AOR=1·61, 95% CI 1·05–2·5,P=0·03), duration of illness >3 days (AOR=1·57, 95% CI 1·0–2·4,P=0·047), and asexual parasite densities less than 5000/μl (AOR=0·42, 95% CI 0·24–0·73,P=0·002). The presence of patent gametocytaemia at enrolment (AOR=0·04, 95% CI 0·02–0·07,P2 days) was associated with increased risk of subsequent gametocyte carriage. These findings may have implications for malaria control efforts in sub-Saharan Africa where control of the disease depends almost entirely on chemotherapy.

This study seeks to understand the experiences of college student as they completed their education during the COVID-19 lockdown. Participants: Students at a large 4-year college in Midwestern USA....