Malaria burden and treatment targets in Kachin Special Region II, Myanmar from 2008 to 2016: A retrospective analysis.

Although drug-based treatment is the primary intervention for malaria control and elimination, optimal use of targeted treatments remains unclear. From 2008 to 2016, three targeted programs on treatment were undertaken in Kachin Special Region II (KR2), Myanmar. Program I (2008-2011) treated all confirmed, clinical and suspected cases; program II (2012-2013) treated confirmed and clinical cases; and program III (2014-2016) targeted confirmed cases only. This study aims to evaluate the impacts of the three programs on malaria burden individually based on the annual parasite incidence (API), slide positivity rate (SPR) and their relative values. The API is calculated from original collected data and the incidence rate ratio (IRR) for each year is calculated by using the first-year API as a reference in each program phase across the KR2. Same method is applied to calculate SPR and risk ratio (RR) at the sentinel hospital too. During program I (2008-2011), malaria burden was reduced by 61% (95%CI: 58%-74%) and the actual API decreased from 9.8 (95%CI: 9.6-10.1) per 100 person-years in 2008 to 3.8 (3.6-4.1) per 100 person-years in 2011. Amid program II (2012-2013), the malaria burden increased by 33% (95%CI: 22%-46%) and the actual API increased from 2.1(95%CI: 2.0-2.3) per 100 person-years in 2012 to 2.8 (95%CI: 2.7-2.9) per 100 person-years in 2013. During program III (2014-2016) the malaria burden increased furtherly by 60% (95%CI: 51% - 69%) and the actual API increased from 3.2(95%CI: 3.0-3.3) per 100 person-years in 2014 to 5.1 (95%CI: 4.9-5.2) per 100 person-years in 2016. Results of the slide positivity of the sentinel hospital also confirm these results. Resurgence of malaria was mainly due to Plasmodium vivax during program II and III. This study indicates that strategy adopted in program I (2008-2011) should be more appropriate for the KR2. Quality-assured treatment of all confirmed, clinical and suspected malaria cases may be helpful for the reduction of malaria burden.