One of the proposed ideas for malaria elimination includes the use of drugs to interrupt malaria transmission by exhausting the human reservoir of infection. Theoretically, mass treatment of an entire population with a very effective and rapid-acting drug (for instance an ACT), followed by the administration of an effective prophylactic regime during a minimum of four weeks, so as to outlast the typical development period of Plasmodium parasites in Anopheline mosquitoes, could achieve the same objective. In this respect, chloroquine (CQ) would be an appropriate candidate. This drug exhibits two conditions that make it attractive for elimination campaigns: 1) It has been demonstrated to have an excellent safety profile, allowing for its use in all age groups including pregnant women and children; and 2) Its relatively long elimination half life (t1/2=1-2 months) can provide a long post-treatment prophylactic effect. Recent evidence suggests that CQ sensitivity may be returning in places where discontinuation has reduced the drug pressure to the parasite populations. In countries such as Malawi, P. falciparum seems to have regained full sensitivity to CQ, and molecular markers of antiCQ resistance have nearly disappeared. While this does not support the reintroduction of CQ as first line therapy, it does suggest that, if proven sensitive in a given area, it could play a prophylactic role in malaria elimination strategies when used in combination with other drugs or tools. Thus, we intend to evaluate the potential role of chloroquine in preventing infections during elimination campaigns by performing a randomized, single-blind, placebo-controlled trial in asymptomatic Mozambican adults. Choosing asymptomatic parasitaemic adult males from a malaria-endemic area as our study population introduces limited risks when administering a drug with an uncertain efficacy (47% efficacious in 2001-2002). In malaria-endemic areas, this age group has a remarkably low risk of developing severe disease (irrespective of clinical symptoms), and it is foreseeable that parasitemia may be well tolerated, and in certain cases, spontaneously cleared from the individual's blood as a result of the immune system. In the unlikely event of any clinical symptomatology appearing throughout the follow-up, individuals will be examined by a study clinician and treated immediately with the country's first-line malaria treatment (artemether-lumefantrine, Coartem ®).
Name: Chloroquine
Description: Chloroquine sulphate (Meriquine®; 250mg; 150 mg of chloroquine base; Baroda, India) will be administered at a total dose of 25 mg/kg (expressed as mg of CQ base per kg body weight, once daily during 3 consecutive days, following the schedule 10mg/kg Day 1; 10mg/kg day 2 and 5 mg/kg day 3).Type: DrugChloroquine
Name: Placebo
Description: Placebo Placebo pills will be standard placebo capsules filled with powder contents with no pharmaceutical activity. They will not be identical to the chloroquine tablets, so the study will not be double blind, but rather single blinded. Placebo tablets will be manufactured by the pharmaceutical department of the Hospital Clínic, in Barcelona, SpainType: DrugPlacebo
Description: the absence of parasitemia at the end of the trial's follow-up period (Day 28), regardless of axillary temperature, without having previously met any of the criteria for early and late treatment failure
Measure: Adequate parasitologic response (APR) to therapy Time: 28 days after first day of drug intakeDescription: Detection of parasites once the initial parasitemia has been cleared in the time period from day 1 to day 3 after first day of drug intake
Measure: Early parasitologic failure Time: 1-3 days after first day of drug intakeDescription: The detection of parasites in patients having cleared their initial parasitemia anytime from day 4 to day 28
Measure: Late parasitologic failure Time: 4-28 days after first day of drug intakeDescription: Proportion of the isolates detected with this specific mutation among isolates at baseline (before study drug initiation)
Measure: Prevalence of chloroquine conferring pfcrt K76T mutation in pre-treatment infections Time: 0 days after first day of drug intakeDescription: Proportion of the isolates detected with this specific mutation at baseline among cases with confirmed treatment failure those
Measure: Rates of pre treatment pfcrt K76T mutation in cases of chloroquine treatment failure Time: 0 days after first day of drug intakeDescription: Proportion of the isolates detected as new infections or recrudescent ones with this specific mutation
Measure: Rates of post treatment pfcrt K76T mutation in cases of chloroquine treatment failure Time: 28 days after first day of drug intakeDescription: time in hours until the clearance of parasitemia
Measure: Clearance time of parasitaemia Time: 28 days after first day of drug intakeAllocation: Randomized
Parallel Assignment
There is one SNP
Prevalence of chloroquine conferring pfcrt K76T mutation in pre-treatment infections. --- K76T ---
Rates of pre treatment pfcrt K76T mutation in cases of chloroquine treatment failure. --- K76T ---
Rates of post treatment pfcrt K76T mutation in cases of chloroquine treatment failure. --- K76T ---