Abstract
BackgroundThe Nias district of the North Sumatra Province of Indonesia has long been known to be endemic for malaria. Following the economic crisis at the end of 1998 and the subsequent tsunami and earthquake, in December 2004 and March 2005, respectively, the malaria control programme in the area deteriorated. The present study aims to provide baseline data for the establishment of a suitable malaria control programme in the area and to analyse the frequency distribution of drug resistance alleles associated with resistance to chloroquine and sulphadoxine-pyrimethamine.MethodsMalariometric and entomology surveys were performed in three subdistricts. Thin and thick blood smears were stained with Giemsa and examined under binocular light microscopy. Blood blots on filter paper were also prepared for isolation of parasite and host DNA to be used for molecular analysis of band 3 (SAO), pfcrt, pfmdr1, dhfr, and dhps. In addition, haemoglobin measurement was performed in the second and third surveys for the subjects less than 10 years old.ResultsResults of the three surveys revealed an average slide positivity rate of 8.13%, with a relatively higher rate in certain foci. Host genetic analysis, to identify the Band 3 deletion associated with Southeast Asian Ovalocytosis (SAO), revealed an overall frequency of 1.0% among the 1,484 samples examined. One hundred six Plasmodium falciparum isolates from three sub-districts were successfully analysed. Alleles of the dhfr and dhps genes associated with resistance to sulphadoxine-pyrimethamine, dhfr C59R and S108N, and dhps A437G and K540E, were present at frequencies of 52.2%, 82.5%, 1.18% and 1.18%, respectively. The pfmdr1 alleles N86Y and N1042D, putatively associated with mefloquine resistance, were present at 31.4% and 2%, respectively. All but one sample carried the pfcrt 76T allele associated with chloroquine resistance. Entomologic surveys identified three potential anopheline vectors in the area, Anopheles barbirostris, Anopheles kochi and Anopheles sundaicus.ConclusionThe cross sectional surveys in three different sub-districts of Nias District clearly demonstrated the presence of relatively stable endemic foci of malaria in Nias District, North Sumatra Province, Indonesia. Molecular analysis of the malaria parasite isolates collected from this area strongly indicates resistance to chloroquine and a growing threat of resistance to sulphadoxine-pyrimethamine. This situation highlights the need to develop sustainable malaria control measures through regular surveillance and proper antimalarial drug deployment.
Highlights
The Nias district of the North Sumatra Province of Indonesia has long been known to be endemic for malaria
Nias district was among the first locations in Indonesia where cases of chloroquine resistance in Plasmodium vivax were found [4,5]
Studies associated with the mosquito vectors revealed several anopheline mosquitoes in Nias, including Anopheles sundaicus, Anopheles sinensis, Anopheles tessellates, Anopheles crawfordi and Anopheles kochi [2,6,7], but only the first three species have been confirmed to transmit malaria
Summary
The Nias district of the North Sumatra Province of Indonesia has long been known to be endemic for malaria. The Nias archipelago has been known to be endemic for malaria long before the natural disasters that hit the area in December 2004 and March 2005 [1,2], and to be a focus of drug resistant malaria. Both in vivo and in vitro chloroquine in Nias were described as early as 1981 [3]. The recent monetary crisis and natural disasters have led to a deterioration of the malaria control programme in the area, culminating in the persistence of a relatively stable endemic focus and outbreak of malaria in many places after the tsunami [8]
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