In the NT, Barmah Forest (BF) case notifications have increased dramatically since October 2012, with a total of 365 notifications between October 2012 and July 2013. Most of the cases were recoded in Darwin urban areas. As part of an investigation into the possible causes for the increase in BF cases, Medical Entomology carried out mosquito trapping and virus isolations in May 2013, in liaison with the Department of Primary Industry and Fisheries to investigate possible high levels of BF virus circulating in wild mosquito populations in the Darwin urban area.