Seasonal malaria chemoprevention (SMC) is adopted and implemented in Senegal since 2013 in the southern regions in children aged between 3 and 120 months. Scaling up of this strategy requires its evaluation to assess its impact. This study was carried out to determine the dynamics of Plasmodium falciparum carriage before and after two years of SMC implementation.

Four household surveys were conducted in villages in the health district of Saraya, which is a SMC implementation area in Senegal. These villages were selected using probability proportional to size sampling. Each of the selected villages was divided into segments containing at least 50 children. In each selected segment, a household questionnaire was administered to the parents or legal representatives of children aged 3 to 120 months. Blood smears were collected to determine Plasmodium falciparum prevalence by microscopy one month before the first round of SMC and one month after the last round of the first SMC campaign and that of two years after the start of the implementation. 

A total of 2008 children were included in our study with a mean average age of 4.81 (+/-2.73) years. 50.33% of the study population were more than 5 years old and 50.3% were male. In 2013, net ownership was 99.4 % before SMC campaign and 97.4% after. In 2015, it was 36.6% before and 45.8% after the campaign. In 2013, the prevalence of plasmodium carriage was 11.8% before and 6.1% after SMC campaign. In 2015, the prevalence was 4.9% before the administration of SMC and increased up to 15.3% after. Malaria prevalence was high among children over 5 years old and boys. 

The decrease in Plasmodium falciparum parasite prevalence, which subsequently increased after two years of SMC implementation in this study, suggests adding an extra cycle of the SMC or adjusting the administration period.

Four cross sectional household surveys were conducted during this study. In 2013, baseline surveys were carried out in August while SMC mass campaigns were performed in November and December. The surveys were conducted again one month after the campaign in January 2014. Two other surveys were conducted in August and December 2015 while SMC campaigns were performed from September to November i.e., one month before and one month after the last cycle of SMC. The study population consisted of three to 120 months old children living in Saraya district. The study inclusion criteria were the parents' consent, apparent good health, absence of fever in the week prior to our visit, being between three and 120 months of age and residing in the study area for the entire period of SMC administration. A standardized questionnaire was administered to parents or care givers/guardians of each selected child to collect socio-demographic data and to assess the use of malaria prevention measures like the use of mosquito bed nets. A blood smear was taken to determine the prevalence of malaria using microscopy.