Flies carrying enterohemorrhagic Escherichia coli (EHEC) O157 in Japan : A nationwide survey

Abstract

A nationwide survey of flies (mainly house flies) carrying enterohemorrhagic Escherichia coli (EHEC) O157 was undertaken in 15 prefectures during late spring-late summer in 1997. EHEC-carrying flies were collected from 53% (8/15) of the prefectures. These positive flies were found from the northern (Hokkaido) to southern prefectures (Okinawa). The flies were collected at 210 sites in 15 prefectures and EHEC-carrying flies were confirmed at 15 (7.1%) sites (cattle farm, 11/140 and slaughter house, 4/19). The average rate of EHEC-carrying flies to the total number of flies collected at the 15 positive-sites was 7.2%. The EHEC-carrying flies were 23/4161 (0.55%) house flies and 3/967 (0.31%) other flies. The serotypes and toxin types of EHEC isolates in 26 EHEC-positive flies were O157 : H7 : VT 2 (16/26), O157 : H7 : VT1+VT2 (8/26), O26 : H11 : VT1 (1/26) and O115 : H10 : VT1 (1/26), respectively.