Dengue is present in 128 countries worldwide and is still expanding. There is currently no treatment or universally approved vaccine available. Therefore, prevention and control of mosquito vectors remain the most efficient ways of managing the risk of dengue outbreaks. The Stegomyia indices have been developed as quantitative indicators of the risk of dengue outbreaks. However, conflictual data are circulating about their reliability. We report in this article the first extensive study on Stegomyia indices, covering 78 locations of differing environmental and socioeconomic conditions, climate, and population density across Indonesia, from West Sumatra to Papua. A total of 65,876 mosquito larvae and pupae were collected for the study. A correlation was found between incidence and human population density. No correlation was found between the incidence of dengue and the Stegomyia indices.

The prevalence of antibodies against spotted fever group rickettsia (SFGR), murine typhus and Q fever were investigated in wild rats captured in Indonesia. Sera of 327 rats were collected from Jakarta and Boyolali on Java Island. The prevalences of antibodies against SFGR and murine typhus were 128 (39.1%) and 48 (14.7%), respectively. Antibodies against Q fever were not detected in these serum samples. Antibodies against SFGR were found in all species of rats (20.8-51.9%). The antibody positive rate against murine typhus in Rattus norvegicus (38.0%) was significantly higher than that in other rat species (0-4.8%, p<0.01). The antibody positive rates against SFGR and murine typhus in rats captured in Jakarta were significantly higher than those in rats captured in Boyolali (p<0.01). In this survey, all species of rats had antibodies against SFGR, indicating that the 4 species of tested rats (R. norvegicus, R. rattus, R. exulans, R. tiomanicus) were infected with SFGR and that SFGR may infest the whole of Java Island. Most of the rats that were antibody-positive against murine typhus were captured in Jakarta. Therefore, R. norvegicus and R. rattus are likely to be important hosts of murine typhus in Jakarta. The antibody-positive rates against SFGR and murine typhus in rats captured in the dry season were significantly higher than those in rats captured in the rainy season. This may coincide with the active periods of ticks and fleas in Indonesia.

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Insecticide resistance is a major problem in dengue vector control in Indonesia. Salatiga City, one of Central Java's dengue-endemic areas, has been using insecticide for vector control for decades. To select the insecticide used, it is necessary to understand the status and mechanism of resistance to various insecticides. This study aimed to determine the status and mechanism of Aedes aegypti resistance in Salatiga City. This study used a descriptive method. Larvae were collected from 8 endemic villages in Salatiga City. The larvae were then reared to produce adult mosquitoes. A resistance test was conducted using the WHO-Impregnated paper method on F1 mosquitoes. The insecticides used for the test were malathion 5%, phenytotrione 1% (Organophosphate); Bendiocarb 0.1%, Propoxur 0.1% (Carbamate); Lambda Cyhalothrin 0.03%, Deltamethrin 0.05%, Permethrin 0.25%, and Cypermethrin 0.05.% (Pyretrhoid). To determine the resistance mechanism of the target site mutation, sequencing of the Domain II VGSC and ACE1 genes was carried out. The test results showed that Ae. aegypti from 8 locations were resistant to all insecticides. The highest mortality after 24 hours observation was on organophosphate group. Molecular tests showed that Single Nucleotide Polymorphism had occurred in the S989P and V1016G alleles of the VGSC gene, indicating molecular resistance to Pyretrhoid insecticides. The ACE1 gene sequences showed no mutations in the G119S allele, indicating the possibility of metabolic resistance to organophosphates and carbamates. In case of a dengue outbreak, it is recommended to use organophosphate because it has the highest percentage of mosquito mortality, and only metabolic resistance occurs without target site mutations.