West Nile virus detected in Dorchester

A mosquito pool in Dorchester has tested positive for West Nile virus, the Boston Public Health Commission said Wednesday. No human cases in the city have been reported this year; six cases were confirmed last year. Mosquito pools — traps that capture mosquitoes for testing — in Hyde Park, Roslindale, West Roxbury, Jamaica Plain, and Fenway have also had positive tests this year, but the recent announcement was Dorchester’s first.