Progress towards malaria elimination in Sabang Municipality, Aceh, Indonesia

Abstract

Background: Indonesia has set 2030 as its deadline for elimination of malaria transmission in the archipelago, with regional deadlines established according to present levels of malaria endemicity and strength of health infrastructure. The Municipality of Sabang which historically had one of the highest levels of malaria in Aceh province aims to achieve elimination by the end of 2013.

Method: From 2008 to 2010, baseline surveys of malaria interventions, mapping of all confirmed malaria cases, categorization of residual foci of malaria transmission and vector surveys were conducted in Sabang, Aceh, a pilot district for malaria elimination in Indonesia. To inform future elimination efforts, mass screening from the focal areas to measure prevalence of malaria with both microscopy and PCR was conducted. G6PD deficiency prevalence was also measured.

Result: Despite its small size, a diverse mixture of potential malaria vectors were documented in Sabang, including Anopheles sundaicus, Anopheles minimus, Anopheles aconitus and Anopheles dirus. Over a two-year span, the number of sub-villages with ongoing malaria transmission reduced from 61 to 43. Coverage of malaria diagnosis and treatment, IRS, and LLINs was over 80%. Screening of 16,229 residents detected 19 positive people, for a point prevalence of 0.12%. Of the 19 positive cases, three symptomatic infections and five asymptomatic infections were detected with microscopy and 11 asymptomatic infections were detected with PCR. Of the 19 cases, seven were infected with Plasmodium falciparum, 11 were infected with Plasmodium vivax, and one subject was infected with both species. Analysis of the 937 blood samples for G6PD deficiency revealed two subjects (0.2%) with deficient G6PD.

Discussion: The interventions carried out by the government of Sabang have dramatically reduced the burden of malaria over the past seven years. The first phase, carried out between 2005 and 2007, included improved malaria diagnosis, introduction of ACT for treatment, and scale-up of coverage of IRS and LLINs. The second phase, from 2008 to 2010, initiated to eliminate the persistent residual transmission of malaria, consisted of development of a malaria database to ensure rapid case reporting and investigation, stratification of malaria foci to guide interventions, and active case detection to hunt symptomatic and asymptomatic malaria carriers.

Figure 1

Map of Sabang Municipality and Weh Island showing position of Sabang in Indonesia and sub villages within the municipality.

Figure 2

Average monthly rainfall and median monthly malaria cases in Sabang from 2005 – 2009.

Figure 3

Confirmed malaria cases per thousand population in Sabang based upon available passive surveillance data, showing major interventions and drugs used for treatment from 1977 to 2011. DDT: dichlorodiphenyltrichloroethane, ACT: Artemisinin-based Combination Therapy, LLIN: Long Lasting Insectiside Treated Bednets, IRS: Indoor Residual Spraying, CI: Case Investigation, ACD: Active Case Detection

Figure 4

Examples of anopheles larval habitats in Sabang.

Figure 5

Coverage of LLINs and IRS per household in Sabang, 2009. Black: both interventions present; white: neither intervention present; hatched: LLINs but no IRS; gray, IRS but no LLINs.

Figure 6

Distribution of malaria cases in Sabang from 2007 to 2010 based upon passive and active surveillance.

Figure 7

Classification of Malaria Foci in Sabang.