The study was undertaken in two neighboring health districts (Kita and Bafoulabe) in the health district of Kita, located in western Mali. The two districts have a combined population of about 670,000 (RGPH 2008, (15)) that are served by 67 community health centers and two referral health centers (equivalent to a district hospital). The study areas have the same geographic, demographic and epidemiological characteristics including a sahelian climate with a single rainy season from July to October. SMC implementation covering children 3–59 months has been occurring in the district of Kita by the National Malaria Control Program since 2014, with four monthly rounds from August to November for two years (2014, 2015, and 2016).
This non-randomized, pre-post design study was conducted among children aged 5 to 10 years in both an intervention (Kita) and control (Bafoulabe) district.
Sample size: A recent Cochrane review on SMC, estimated that SMC can reduce parasitemia by 65%. For this study, we assume a 50% reduction under programmatic conditions. To detect a 50% difference in parasitemia in older age group between the normal SMC and extended SMC districts at follow-up, with alpha = 0.05, power of 80% and assuming 12.5% and 25% parasitemia in the district at follow-up respectively and design effect 0f 2.0, 304 children aged 5–10 years would be needed to be surveyed in each district. Assuming one child 5–10 years old per household, survey teams would need to visit 304 households in each of the two districts at baseline and follow-up each year (total sample size = 608 household at baseline and 304 at follow-up for the 2 years of data collection; 1,216 children from 5 to 10 years were assessed). In each district, 304 households were randomly selected according to adherence to the study after signed consent.
At baseline 323 children in Bafoulabé and 310 in Kita were enrolled in the study. For post-intervention surveys, a total of 279 children in Bafoulabé district and 372 children in Kita district were enrolled in the study. One child by household was randomly selected in the selected village. SMC implementation consisted of the administration of SP + AQ at monthly intervals in children aged 3–59 months old and to children aged 5 to 10 years in July, August, September and October 2017 and 2018 to all eligible children.
To estimate parasitic infection and anemia, we conducted a cross-sectional survey in the two districts one month after the 4th round of SMC.
Written informed consent was obtained from all participants’ mothers or guardians prior to inclusion. Each child gave a blood sample for hemoglobin measurement using a HemoCue device, and for malaria parasite detection using a blood smear and filter paper for molecular markers of the resistance to SP and AQ
Drug adverse events were monitored by household visit 4–7 days after each of the four rounds of SMC in the intervention district of Kita. Community based distributors (CBD) checked any reactions to treatment, documented and reported to the nearest health center. Laboratory investigation were conducted in cases of severe skin reactions and signs of liver disease.
Delivery and Drugs
A therapeutic dose of the standard drug regimen per WHO, AQ (10 mg/kg/day for 3 days) combined with one dose of SP on the first day (25 mg Sulfadoxine and 1.25 mg pyriméthamine per kg) was administered once per month from July to October to all children 3–59 months old in both districts and to children from 5 to 10 years in Kita; SMC first dose was given by CBDs by door to door strategy and the subsequent doses were given by mothers or the child’s guardian. For data monitoring of the first dose n was recorded in registers maintained by the CBDs. The administration at home was recorded to SMC cards maintained by the parents.
HemoCue device (Angelholm, Sweden) was used to measure hemoglobin levels in the field among children who had blood samples by finger prick.
Anemia classification according DeMaeyer was used (16):
Children with hemoglobin level below 8.0 g / dl were classified as patients with severe anemia; between 8.0 and 9.9 g / dL for moderate anemia and between 10.0 and 10.9 g / dl for mild anemia.
The thick and thin smears were performed in each child participating in the study. The slides were labeled with a unique identification number of child and dated. The slides were dried in open air in slide boxes and then transferred at the end of day in slide boxes for safe storage. Thin smears were fixed with methanol. The slides were stained using Giemsa 10% and transported to the laboratory in the Malaria Research and Training Center in which they were read by two independent readers.
Malaria disease was defined as axillary temperature ≥ 37.5 °C and the presence of asexual malaria parasites in the blood smear. In addition to previous conditions, prostration or convulsions or coma will be considered as severe malaria and requested specific management.
Confirmed malaria data from July to December 2017 and July to December 2018 were collected from outpatient registers in community health centers. A total of 5 centers were randomly selected in each of the two districts from the ten best performing centers in each district based on certain performance criteria (accuracy, completeness of consultation registers). This passive surveillance allowed for the assessment of trends of malaria burden in children aged 5–10 years.
Data management and analysis
Data on each participant were collected by the study team on the Case Report Forms (CRF) kept in place in accordance with good clinical practices. These data from household survey and health facilities were double entered in ACCESS 2010 by two different operators. The prevalence of anemia and malaria parasitemia was compared in intervention and control districts one month after the fourth round of SMC. Logistic regression was used for binary outcomes of anemia, malaria disease and parasitemia, and used a difference-in-differences approach. The level of significance was set at 5%.
Assessment of molecular markers of resistance to SP and AQ
Molecular analysis was performed on samples from children with hose blood smear showed P. falciparum parasitaemia ≥ 160/uL (4 parasites/200 WBC) by blood smear. Blood samples on paper filter were analysed by nested polymerase chain reaction (PCR) and/or PCR-restriction fragment length polymorphism (RFLP) for mutations at codons 51, 59 and 108 of the dhfr gene, 437 and 540 of the dhps gene, mutations at codon 76 in the P. falciparum chloroquine transporter gene (pfcrt), and at codon 86 of the P. falciparum multidrug resistance gene one (pfmdr1) according to published methods (17, 18). Cases of mixed infection (wild type and mutant) were categorized as mutant. Quintuple mutant was defined as the presence of the three dhfr mutations (N51I, C59R and S108N) and the two dhps mutations (A437G and K540E).
The study protocol was approved by the ethics committees of Faculty of Medicine and Odonto- stomatology of Bamako and CDC in Atlanta. Written informed consent from parents/ guardians was obtained for all participants by explaining the aims and activities prior to seeking signed consent. The study objectives and data collection procedures were explained in detail to administrative, community and health authorities. Only ID numbers of participants were on the samples and CRFs to ensure anonymity and confidentiality.