Evolution of Intermittent Screening and Treatment for Malaria in Pregnancy Control

Intermittent Preventive Treatment of pregnant women (IPTp) for malaria has been a major, if not terribly well implemented malaria control strategy in countries with high and stable malaria transmission. Combined with use of insecticide treated nets (ITNs) and appropriate case management with artemisinin-based combination therapy (ACTs), IPTp offered an important third prong to protect this vulnerable population who in theory are reachable since most pregnant women in endemic countries attend antenatal care (ANC).

dscn8010-sm.JPGThe area benefiting from IPTp covers the bulk of sub-Saharan Africa, but not countries on the periphery of malaria transmission, like Namibia and Botswana, where transmission is seasonal or epidemic. Here, as well as in countries that have made substantial progress in reducing the burden of malaria like Rwanda, ITNs themselves often carry the burden of protecting pregnant women since case management is dependent of treatment seeking in a variety of formal and non-formal care settings.

IPTp as we know it is threatened. First is the growing resistance of malaria parasites to sulphadoxine-pyrimethamine (SP), the drug of choice. The problem has been compounded by countries’ neglect in curbing the continued and unrecommended use of SP for treatment. Secondly, on a more positive note, as countries reduce their malaria burden and become more like those with low and unstable transmission, widespread IPTp does not make much sense as a strategy.

This reduction in burden does not mean that pregnant women are no longer at risk in malaria endemic countries that are making progress.  It means that aside from continued use of ITNs and other vector management interventions, we must step up the accuracy of timely case detection and case management.

A new study of malaria rapid diagnostic tests during pregnancy in Tanzania sums up the current situation nicely: “Microscopy underestimated the real burden of malaria during pregnancy and RDTs performed better than microscopy in diagnosing PAM. In areas where intermittent preventive treatment during pregnancy may be abandoned due to low and decreasing malaria risk and instead replaced with active case management, screening with RDT is likely to identify most infections in pregnant women and out-performs microscopy as a diagnostic tool.”

dscn7279sm.jpgOthers have suggested an active detection and case management process using ANC as a platform – intermittent screening and treatment (IST). One of the earliest allusions to IST was in a 2008 study in Ghana, where the researchers concluded that RDTs fit easily into ANC procedures and outlined the benefits of “antenatal RDT screening and treatment.” One of the researchers actually used the term IST during a presentation on malaria intervention options for Asia at the 11th meeting of the Roll Back malaria Partnership’s Malaria in Pregnancy Working Group in 2008.

In 2010 the same research team again reported from Ghana on comparing IPTp during ANC with IST using two different drug regimens. All three arms showed a reduction of parasitemia near the end of their pregnancies, but with the benefit of reduced drug use in the two IST arms.

Research continues on IST. Rwanda has recently completed a malaria in pregnancy prevalence study using RDTs and treatment of those with parasitemia during first ANC visit and is in the process of determining guidelines for formalizing this as part of ANC.  School based studies of IST in Kenya have yielded encouraging results. Unicef in collaboration with USAID is piloting IST in selected regions of Indonesia.

Practical issues of integrating the RDT testing and ACT provision need to be addressed including funding and procurement processes to ensure adequate supplies at ANC. Training of ANC workers on the procedures as well as planning on how to ensure IST fits seamlessly into ANC procedures are a few of the operational challenges.

In conclusion, IST offers a promising intervention in low transmission countries as well as high burden countries as they move closer to elimination. As with most malaria interventions, the science will be easier to solve than the logistics and staff attitudes.

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