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Background and Aim: To effectively control dengue hemorrhagic fever (DHF), it is necessary to assess the risk of vertical virus transmission in Aedes aegypti mosquitoes. This study aimed to detect dengue virus (DENV) transovarial transmission in A. aegypti collected from DHF patients' residences in Denpasar, Bali. Materials and Methods: A. aegypti samples were acquired by rearing A. aegypti eggs collected from ovitraps placed in the homes of DHF patients. Ovitraps were installed for 7 days and viewed using a loupe to determine whether there were Aedes spp. eggs present. An immunocytochemical method was utilized with 200 samples, and virus detection was performed using a reverse transcriptase-polymerase chain reaction (RT-PCR). Results: Of the 10 DHF patient houses fitted with ovitraps, four produced positive ovitraps from which larvae developed (house index=40%). Of the 50 ovitraps mounted in the 10 homes, 14 ovitraps were positive and contained A. aegypti eggs (ovitrap index=28%). Of these 14 positive ovitraps containing A. aegypti eggs, 10 ovitraps produced larvae. Immunocytochemical tests were conducted on A. aegypti eggs from the four houses under study. It was found that from the 200 samples collected, 197 samples could be observed, and 11 samples (5.6%) were positive for DENV antigen. RT-PCR examination conducted on mosquitoes reared from the four houses studied obtained a negative virus content result. Conclusion: This study found the presence of DENV antigen to be as high as 5.6%. This means that potential for transovarial transmission exists within DHF patients' homes in Denpasar, Bali. Aedes control strategy in Denpasar should address this finding, in addition to the current approaches which have focused primarily on the elimination of larval breeding habitats and control of adults using insecticidal fogging during outbreaks.

IntroductionTaeniasis/cysticercosis, caused by the pork tapeworm, Taenia solium, is a parasitic zoonosis found primarily in countries where pigs are raised and meat inspection is lacking [1,2]. The potential for a tapeworm carrier to infect another individual (or themselves via autoinfection), resulting in cysticercosis or neurocysticercosis (NCC), is a risk not only in endemic areas, but also in areas with immigrants from endemic countries [1,[3][4][5]]. An example of such an outbreak occurred in an Orthodox Jewish community in New York City when family members were infected by a domestic employee from a T. solium endemic country [6]. Such NCC outbreaks have occurred in other developed countries, including countries in the Middle East where people do not consume pork [4,5,[7][8][9][10][11][12][13].In Asia, there are three Taenia tapeworms that infect humans; T. solium, Taenia saginata and Taenia asiatica [4,5,[14][15][16][17][18][19][20][21][22][23][24]. Although adult T. solium worms with scoleces are easily differentiated morphologically from other taeniids, it is almost impossible to differentiate adult T. asiatica and T. saginata [5,22,25,26]. Therefore, molecular differentiation is often required to correctly identify the infecting species [27]. Recent studies have also reported hybrids of T. saginata and T. asiatica in Thailand and China [5,25,[28][29][30][31][32]. This makes mitochondrial and nuclear gene analyses even more important for the differentiation of T. saginata, T. asiatica, and hybrids of these two species [30][31][32].In Indonesia, T. solium, T. saginata and T. asiatica are distributed according to livestock rearing and local food consumption practices [33][34][35][36][37][38][39][40]. Both T. saginata and T. solium have been confirmed from the island of Bali, where the local inhabitants are known to eat dishes that contain undercooked beef and pork, such as the traditional dish Lawar. NCC was considered endemic on Bali more than 20 years ago [41,42]. However, education programs aimed at keeping pigs indoors to prevent access to human faeces and the introduction of improved sanitation systems and practices have substantially reduced the prevalence of NCC during the past 2 decades [35,37,43]. Nevertheless, there are still sporadic NCC cases identified on Bali [40,[42][43][44][45]. Case ReportFieldwork conducted on Bali from 2002-2007 resulted in the identification of 69 taeniasis carriers who were treated with a single dose of praziquantel (PZQ) at 15 mg/kg body weight (Table 1). All worms were confirmed to be T. saginata by multiplex PCR [36]. In August 2007, a 47-year-old male taeniasis carrier from the Gianyar district suffered a single tonic-clonic seizure within a few hours of PZQ administration. The patient was subsequently admitted to the Sanglah Hospital in Denpasar. A computed tomography (CT) scan revealed one viable cystic lesion and one calcified lesion in the right frontal lobe of the brain. At this time, serology (ELISA) was also carried out using partially purified antigens by c...

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