Abstract. A randomized, double-blinded, placebo-controlled study was conducted to examine the effect of spatial repellent (SR) in households at risk of malaria in Indonesia. Following presumptive radical cure for malaria in 180 adult men representing sentinels of new infection in four clusters within two villages, all households were given either metofluthrin or placebo mosquito coils. Weekly blood smear screening and human-landing mosquito catches were done throughout the 6 months intervention. Malaria infections occurred in 61 subjects living in placebo households and 31 subjects living in SR coil households, suggesting a 52% protective effect of SR. Likewise, anopheles indoor human landing rates were 32% lower in homes receiving SR coils. Differences in the malaria attack rate between SR-and placebo-treated homes was significant when not accounting for the effects of clustering. When the analysis was adjusted for intra-cluster correlation, the differences between SR-and placebo-treated homes were not statistically significant. The findings provide evidence of SR public health benefit and support a larger trial statistically powered to detect those effects.

Dengue fever is currently the most important mosquito-borne viral disease in Indonesia. In South Sulawesi province, most regions report dengue cases including the capital city, Makassar. Currently, no information is available on the serotypes and genotypes of the viruses circulating in the area. To understand the dynamic of dengue disease in Makassar, we carried out dengue fever surveillance study during 2007-2010. A total of 455 patients were recruited, in which antigen and serological detection revealed the confirmed dengue cases in 43.3% of patients. Molecular detection confirmed the dengue cases in 27.7% of patients, demonstrating that dengue places a significant disease burden on the community. Serotyping revealed that dengue virus serotype 1 (DENV-1) was the most predominant serotype, followed by DENV-2, -3, and -4. To determine the molecular evolution of the viruses, we conducted whole-genome sequencing of 80 isolates. Phylogenetic analysis grouped DENV-2, -3 and -4 to the Cosmopolitan genotype, Genotype I and Genotype II, respectively. Intriguingly, each serotype paints a different picture of evolution and transmission. DENV-1 appears to be undergoing a clade replacement with Genotype IV being supplanted by Genotype I. The Cosmopolitan DENV-2 isolates were found to be regionally endemic and is frequently being exchanged between countries in the region. By contrast, DENV-3 and DENV-4 isolates were related to strains with a long history in Indonesia although the DENV-3 strains appear to have been following a distinct evolutionary path since approximately 1998. To assess whether the various DENV serotypes/genotypes possess different growth characteristics, we performed growth kinetic assays on selected viruses. We observed the relatively higher rate of replication for DENV-1 and -2 compared to DENV-3 and -4. Within the DENV-1, viruses from Genotype I grow faster than that of Genotype IV. This higher replication rate may underlie their ability to replace the circulation of Genotype IV in the community.

BackgroundMass screening and treatment (MST) aims to reduce malaria risk in communities by identifying and treating infected persons without regard to illness.MethodsA cluster-randomized trial evaluated malaria incidence with and without MST. Clusters were randomized to 3, 2, or no MST interventions: MST3, 6 clusters (156 households/670 individuals); MST2, 5 clusters (89 households/423 individuals); and MST0, 5 clusters (174 households/777 individuals). All clusters completed the study with 14 residents withdrawing. In a cohort of 324 schoolchildren (MST3, n = 124; MST2, n = 57; MST0, n = 143) negative by microscopy at enrollment, we evaluated the incidence density of malaria during 3 months of MST and 3 months following. The MST intervention involved community-wide expert malaria microscopic screening and standard therapy with dihydroartemisinin-piperaquine and primaquine for glucose-6 phosphate dehydrogenase–normal subjects. All blood examinations included polymerase chain reaction assays, which did not guide on-site treatment.ResultsThe risk ratios for incidence density of microscopically patent malaria in MST3 or MST2 relative to that in MST0 clusters were 1.00 (95% confidence interval [CI], .53–1.91) and 1.22 (95% CI, .42–3.55), respectively. Similar results were obtained with molecular analysis and species-specific (P. falciparum and P. vivax) infections. Microscopically subpatent, untreated infections accounted for 72% of those infected.ConclusionsTwo or 3 rounds of MST within 3 months did not impact the force of anopheline mosquito-borne infection in these communities. The high rate of untreated microscopically subpatent infections likely explains the observed poor impact.Clinical Trials RegistrationNCT01878357.

Background Understanding local Anopheles species compositions and bionomic traits are vital for an effective malaria vector intervention strategy. Though eight malaria vectors, including species complexes, have been documented across the island of Sulawesi, Indonesia, a comprehensive survey linking morphological and molecular species identification has not been conducted in this global hotspot of biodiversity. Results Eighteen distinct species of Anopheles were molecularly identified in a 1 km 2 area in Karama village, West Mamuju Province, Sulawesi. Known species included An. aconitus , An. karwari , An. peditaeniatus , An. vagus , An. barbirostris , An. tessellatus , An. nigerrimus , An. crawfordi , An. maculatus, An. flavirostris and An. kochi . Of the 18 distinct sequence groups identified through both ribosomal DNA internal transcribed spacer region 2, and mitochondrial DNA cytochrome c oxidase subunit 1 loci, 8 could not be identified to species through comparison to published sequences. The comparison of morphological and molecular identities determined that interpretations of local species compositions for primary and expected species in Karama ( An. barbirostris and An. vagus ) had the highest rate of accuracy (92.1% and 87.6%, respectively) when compared to molecular analysis. However, the remaining distinct sequences molecularly identified to species were identified correctly by morphological methods less frequently, from 0 to 83%. Conclusions Karama, Indonesia has a high diversity of Anopheles spp. The unexpected high number of Anopheles species in a small area points to possible complex transmission dynamics and limitations with vector control based on possible varying behaviors and interactions with both humans and interventions. Morphological identification of Anopheles spp. in this study was more accurate for primary and expected species than secondary or unexpected species. Finally, the inability to identify seven sequence groups to species with consensus sequences implies that future studies employing sequencing are required to clarify species compositions in the Nigerrimus Subgroup, among others, as well as their distribution and vector status. Use of molecular methods in conjunction with morphological investigations for analysis of species composition, population dynamics and bionomic characteristics is directly implicated in understanding drivers of malaria transmission, intervention effectiveness, and the pursuit...

Maxillae and mandibles of males of 44 species of 12 mosquito genera and females of three autogenous genera and two partially autogenous species were examined under light microscopy and scanning electron microscopy. The maxillae and mandibles of male mosquitoes are delicate, tape-like structures with lengths characterizing genera or higher level classification units. Five patterns are recognized: (A) long maxillae and mandibles with mandibles longer than maxillae in Anopheles; (B) long maxillae and mandibles with maxillae longer than mandibles in Toxorhynchites; (C) short or intermediate lengths of maxillae with short mandibles in Aedes, Armigeres, Culex, Ochlerotatus, Orthopodomyia, and Uranotaenia; (D) short or intermediate length of maxillae with no mandibles in Mimomyia and Tripteroides; and (E) no maxillae and mandibles in Malaya and Topomyia. Maxillary and mandibular lengths of male mosquitoes show a positive correlation. Length of maxillae and mandibles of autogenous females are reduced to the same level as conspecific males. In contrast, females of partially autogenous species have complete maxillae and mandibles as in females of anautogenous species.

Significant clustering of malaria parasitemia in close proximity to very specific and relatively few An. sundaicus larval habitats has direct implications for local control strategy, policy, and practice. These findings suggest that larval source management could achieve profound if not complete impact in this region.

Background: Indonesia has high mosquito diversity, with circulating malaria and arboviruses. Human landing catches (HLC) are ethically questionable where arboviral transmission occurs. The host decoy trap (HDT) is an exposure-free alternative outdoor sampling device. To determine HDT efficacy for local culicids, and to characterize local mosquito fauna, the trapping efficacy of the HDT was compared to that of HLCs in one peri-urban (Lakkang) and one rural (Pucak) village in Sulawesi, Indonesia. Results: In Lakkang the outdoor HLCs collected significantly more Anopheles per night (n = 22 ± 9) than the HDT (n = 3 ± 1), while the HDT collected a significantly greater nightly average of Culex mosquitoes (n = 110 ± 42), than the outdoor HLC (n = 15.1 ± 6.0). In Pucak, there was no significant difference in Anopheles collected between trap types; however, the HDT collected significantly more Culex mosquitoes than the outdoor HLC nightly average (n = 53 ± 11 vs 14 ± 3). Significantly higher proportions of blood-fed mosquitoes were found in outdoor HLC (n = 15 ± 2%) compared to HDT (n = 2 ± 0%). More blood-fed culicines were collected with outdoor HLC compared to the HDT, while Anopheles blood-fed proportions did not differ. For the HDT, 52.6%, 36.8% and 10.5% of identified blood meals were on cow, human, and dog, respectively. Identified blood meals for outdoor HLCs were 91.9% human, 6.3% cow, and 0.9% each dog and cat. Mosquitoes from Pucak were tested for arboviruses, with one Culex pool and one Armigeres pool positive for flavivirus, and one Anopheles pool positive for alphavirus. Conclusions: The HDT collected the highest abundance of culicine specimens. Outdoor HLCs collected the highest abundance of Anopheles specimens. Although the HDT can attract a range of different Asian mosquito genera and species, it remains to be optimized for Anopheles in Asia. The high proportion of human blood meals in mosquitoes collected by outdoor HLCs raises concerns on the potential exposure risk to collectors using this methodology and highlights the importance of continuing to optimize a host-mimic trap such as the HDT.

Background: The 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 sulphadoxinepyrimethamine.