A controlled, parallel, cluster-randomized trial of community-wide screening and treatment of asymptomatic carriers of Plasmodium falciparum in Burkina Faso

Malar J. 2013 Feb 27;12:79. doi: 10.1186/1475-2875-12-79.

Abstract

Background: In malaria-endemic countries, large proportions of infected individuals are asymptomatic, constituting a reservoir of parasites for infection of newly hatched mosquitoes. This study evaluated the impact of screening and treatment of asymptomatic carriers of Plasmodium falciparum.

Methods: Eighteen villages were randomized (1:1) to study arms and inhabitants participated in four community screening campaigns: three before the rainy season ~1 month apart, and the fourth after the rains at ~12 months. On day 1 of campaigns 1-3, asymptomatic carriers in the intervention arm were identified by rapid diagnostic test and treated with artemether-lumefantrine. Outcomes were symptomatic malaria with parasite density >5,000/μL per person-year in children < 5 years and change in haemoglobin between days 1 and 28 of campaign 1.

Results: At 12 months, the number of symptomatic malaria episodes with a parasite density >5,000/μL per person-year in children < 5 years was not significantly different between arms (1.69 vs 1.60, p = 0.3482). Mean haemoglobin change in asymptomatic carriers during campaign 1 was greater in the intervention vs control arm (+0.53 g/dL vs -0.21 g/dL, p < 0.0001). ANCOVA demonstrated that mean asymptomatic carriage at the cluster level was lower in the intervention vs control arm at day 1 of campaigns 2 (5.0% vs 34.9%, p < 0.0001) and 3 (3.5% vs 31.5%, p < 0.0001), but showed only a small difference at day 1 of campaign 4 (34.6% vs 37.6%, p = 0.2982). Mean gametocyte carriage was lower in the intervention vs control arm at day 1 of campaigns 2 and 3 (0.7% vs 5.4%, p < 0.0001; 0.5% vs 5.8%, p < 0.0001), but was similar at day 1 of campaign 4 (4.9% vs 5.1%, p = 0.7208).

Conclusions: Systematic screening and treatment of asymptomatic carriers at the community level did not reduce clinical malaria incidence in the subsequent transmission season, indicating greater levels of parasite clearance are required to achieve a sustained impact in this setting.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Antimalarials / administration & dosage*
  • Artemether, Lumefantrine Drug Combination
  • Artemisinins / administration & dosage
  • Asymptomatic Diseases
  • Burkina Faso
  • Carrier State / diagnosis*
  • Carrier State / drug therapy*
  • Child
  • Child, Preschool
  • Clinical Laboratory Techniques / methods*
  • Drug Combinations
  • Ethanolamines / administration & dosage
  • Female
  • Fluorenes / administration & dosage
  • Humans
  • Incidence
  • Infant
  • Malaria, Falciparum / diagnosis*
  • Malaria, Falciparum / drug therapy*
  • Male
  • Mass Screening / methods*
  • Middle Aged
  • Pregnancy
  • Rural Population
  • Treatment Outcome
  • Young Adult

Substances

  • Antimalarials
  • Artemether, Lumefantrine Drug Combination
  • Artemisinins
  • Drug Combinations
  • Ethanolamines
  • Fluorenes