Two new species, Simulium (Simulium) iwasai and S. (S.) obihiroense, are described from females collected from Hokkaido, Japan. Both new species are placed in the S. (S.) venustum species-group. Simulium (Montisimulium) kobayashii Okamoto et al., is newly recorded from Hokkaido. In addition, the male of S. (S.) iwatense (Shiraki) in the S. (S.) ornatum species-group is fully described for the first time based on males reared from pupae collected from Hokkaido.
We report the results of mosquito inspection on international aircraft and in government-run areas by the Japanese Quarantine Station, Ministry of Health, Labour and Welfare between 2008 and 2018. In total, 22,452 aircraft were inspected and 822 adult mosquitoes (including 145 dead mosquitoes) were collected from 240 (1.07%). The majority of the mosquitoes on aircraft belonged to Culex. The most abundant Culex species was Cx. quinquefasciatus and 469 adults were captured. Among them, 398 were collected from aircraft from India. The second-most abundant was Cx. pipiens complex (158 adults) and the third was Cx. gelidus (100 adults). An important invasive dengue vector, Aedes aegypti (2 adults), was captured on an aircraft from the Philippines. In mosquito inspection at government-run areas, the invasion of Ae. aegypti was confirmed at Narita International Airport in 2012, 2013, 2014, 2015, and 2017, Tokyo International Airport (Haneda Airport) in 2013, and Chubu Centrair International Airport (NGO) in 2016 and 2017. Virus detection from the collected mosquitoes revealed Japanese encephalitis virus gene (genotype I, a prevalent genotype in Japan at present) from Cx. tritaeniorhynchus captured at Narita International Airport in 2013, Mikawa Port in 2015, and Kyushu Saga International Airport in 2017.
A new mosquito species, Topomyia (Topomyia) murudensis Miyagi, Toma and Okazawa is described from Mount Murud, Sarawak, Malaysia. The adult male and female, pupa, and larva are described in detail. Illustrations of the male genitalia, the pupa, and fourth instar larva of the species are also provided. Topomyia murudensis sp. nov. is a highland mosquito, presently known to breed only in leaf axils of the highland orchids Cymbidium sp. and Eria sp.
The parous rate of Aedes albopictus was investigated by human bait-sweep net collection in a thicket of Kobe City from 2015 to 2019. The overall parous rates from 2015 to 2019 were 49.7%, 45.3%, 36.9%, 37.2%, and 45.6%, respectively. The results from every investigation year highlighted a relationship between the number of individuals and the parous rates. The relationship was notable in summer. In 2015, when the number of individuals was the highest in the middle of August, the parous rate was high at 68.4%. In 2016, when the number was slightly less in early August and late August, the parous rates were still high, at 63.6% and 76.5%, respectively. During late July and early August in 2017, the numbers were less and the parous rates were low (20.7% and 27.3%, respectively). In 2018, dry ice (300～500 g) was used to attract mosquitoes. A total of 513 individuals were collected in mid-September and the parous rate was 20.0%. In late July and early August, the number of individuals were 31, 35 and the parous rates were 26.7% and 42.4%, respectively. In 2019, when there were a large number of individuals in August and September, high parous rates such as 59.7%, 82.4% were observed.
Severe fever with thrombocytopenia syndrome (SFTS) is a tick-borne diseases caused by the SFTS virus (SFTSV). In recent years, with the expansion of wildlife habitat, the chances of ticks invading a human living area have increased, accompanied by an increased risk of SFTSV infection. Here, we investigated the tick fauna and distribution of SFTSV in Fukuoka Prefecture and analyzed the factors associated with the occurrence of SFTS. A total of 1307 ticks were collected by flagging on vegetation between March and November during the study period from May 2017 to August 2019. Using cluster analysis based on the proportion of tick species at the collection points, we roughly classified the tick fauna in the prefecture into three clusters (Clusters 1–3). The proportion of Haemaphysalis longicornis was extremely high in Cluster 1, and we detected SFTSV in one of the samples. We identified patients in the area of Cluster 1—the habitat of deer—the main host of ticks, which was geographically consistent with the area of Cluster 1. These results suggest that deer habitat, with its high population density of H. longicornis, is implicated in the cluster of patients occurring in Cluster 1 area in Fukuoka Prefecture.