Monitoring malaria parasitemia prevalence among pregnant women at reproductive and child health clinics in the lake zone, Tanzania

Background: Over the past five years, Tanzania has progressively scaled up implementation of combined malaria interventions, including insecticide treated nets (ITNs), Intermittent Preventive Treatment in pregnancy (IPTp), malaria rapid diagnostic tests (mRDTs), and treatment with Artemisinin-based Combination Therapy (ACT). In addition, indoor residual spraying (IRS) is also being implemented in three Lake Zone regions (Kagera, Mwanza, Mara) with the country's highest malaria prevalence (30% - 40% in 2007). Implementation of these interventions created a need to establish malaria surveillance systems. A population-based malaria surveillance system was set up to monitor malaria prevalence among a key sentinel population (pregnant women). Methods: A sentinel surveillance survey was conducted in 49 Reproductive and Child Health (RCH) clinics in Kagera, Mara, and Mwanza regions, to monitor trends in asymptomatic parasitemia. Pregnant women (the sentinel population) attending RCH clinics at their first antenatal care (ANC) visit for any given pregnancy were screened for P. falciparum parasitemia using mRDTs. The screening was independent of the malaria symptoms at the time of the visit. Results: In June-November, 2012, the total number of pregnant women tested for malaria at their first ANC visit was as follows: 4,272 women in Mwanza; 1,575 women in Mara; and 2,517 women in Kagera. The total numbers of positive malaria tests were 282 (6.7%) in Mwanza; 167 (10.6%) in Mara; and 184 (7.3%) in Kagera. Conclusion: Surveillance of sentinel populations will generate longitudinal malaria prevalence data in asymptomatic populations that will guide policy and programmatic decisions for targeting interventions.