A series of the studies on countermeasure for arthropod-borne infectious diseases in Japan —Focus on highly pathogenic avian influenza and dengue outbreaks in Japan—

We have faced a number of outbreaks of arthropod-borne infectious diseases in Japan and aimed to address each case appropriately. Here, I introduce two arthropod-borne infectious diseases caused by flies and mosquitoes, respectively. In 2004, the highly pathogenic avian influenza occurred in Kyoto. The H5N1 influenza A virus was isolated from the blow fly, Calliphora nigribarbis, collected around a poultry farm. Exposure experiments showed that the H5N1 virus survived in C. nigribarbis for at least 24 h. C. nigribarbis was suggested to possibly transport the H5N1 virus over a distance of 2 km, which they can access within 24 h. While in 2014, 162 autochthonous dengue cases were reported. Dengue virus was isolated from Aedes albopictus collected in the suspected locations of dengue virus infection in Tokyo. Phylogenetic analysis and virus infection experiments revealed that Ae. albopictus was a major dengue vector in Tokyo in 2014. In both cases, we first collected vector arthropods at each outbreak location to understand their biological characteristics and ecological dynamics. We then detected pathogens from the collected arthropods and conducted infection experiments in the laboratory. We can understand that obtaining data from both the field and the laboratory is necessary to confront arthropod-borne infectious diseases.