抄録
In Okinawa Prefecture in Japan, although major mumps epidemics have occurred every 4-5 years, no laboratory diagnoses have been conducted. The mumps epidemic spread in Okinawa from October 2014, and we collected clinical materials from 31 mumps patients in 4 areas (Hokubu, Nanbu, Miyako and Yaeyama) from July to December 2015 for virus isolation and RT-PCR, whose positive ratios were 52% and 87%, respectively. The phylogenetic analyses showed that all isolates were classified into genotype G, most of which, except for 1, consisted of two subgenotypes, Ge (55.6%) and Gw (40.7%), which have been prominent in Japan recently. One isolate was classified into another lineage, which was first detected in Japan, and was similar to the Hong Kong isolate in 2014. Remarkably, the geographic distributions of the two major lineages were separated, namely, the Ge viruses were isolated from the main island of Okinawa, and the Yaeyama Islands, while the Gw isolates were mainly detected from the Miyako Islands. These results suggest that Ge and Gw mumps viruses mainly caused the mumps epidemics of 2015 in Okinawa, and they spread independently in separate regions. This is the first report describing the molecular epidemiological studies of mumps epidemics in Okinawa Prefecture.
