Background: Plasmodium spp. asymptomatic carriers are potential reservoirs contributing to the persistence of malaria transmission in endemic areas. The study was designed to assess the extent of Plasmodium spp. asymptomatic infection at household and individual levels and associated risk factors in Northern Côte d’Ivoire.
Methods: A cross-sectional survey was conducted in July 2016 at household level in the health district of Korhogo. A questionnaire was administered to household’s head to capture socio-demographic information and practices including malaria treatment and preventive measures. In each household, adults without malaria symptoms nor history of fever during the week before recruitment were screened. Capillary blood samples were collected and used for the detection of Plasmodium spp. infections using both conventional microscopy and a loop-mediated isothermal DNA amplification (LAMP) assay. Logistic regression was used to determine variables that influenced Plasmodium spp. asymptomatic infections.
Results: In total, 376 households and 1’011 asymptomatic adults were screened. Asymptomatic Plasmodium spp. infections were identified in 12.5% [47/376] and 38.3% [144/376] of the households and in 5.2% [53/1011] and 18.8% [190/1011] of the individuals screened, according to microscopy and LAMP, respectively. At household level, asymptomatic carriers increased about two times when using mosquito repellent coils compared to those where it is not used (OR: 1.8; p=0.005). At individual level, men’s risk to be infected was about two times that of women (OR: 1.9; p<0.001). The odd to be infected was also two times higher in population living in periurban areas compared to those leaving in the urban center (OR: 2.3; p<0.001). Additionally, age appear to be risk factor, with younger individuals being at higher risk of infection than elders (OR: 0.5; p=0.001).
Plasmodium spp. asymptomatic carriers is important in Northern Côte d’Ivoire and male, age under 30 and perirban living area appear as significant risk factors. Interventions aiming at eliminating asymptomatic infections in this context, should primarily target among other strategy, the at-risk populations and zones.