Opportunistic serological surveillance for Murray Valley encephalitis virus in Victoria, February–May 2011

To the Editor: Murray Valley encephalitis virus (MVEV) is rarely seen in south-eastern Australia, as described in the recent review in the Journal by Knox and colleagues.1 During the MVEV transmission period in early 2011, there was extensive flooding, and high notification rates were reported for other mosquito-transmitted infections, including flavivirus infection among horses. MVEV seroconversion was detected in sentinel chicken flocks. However, despite concerns about widespread human disease, there were only four notifications of confirmed cases during this time.2 We designed a study to detect and monitor asymptomatic human transmission of MVEV to aid public health decisions about mosquito control.