To the Editor: The flavivirus Murray Valley encephalitis virus (MVEV) was isolated in 1951 from the brain tissue of fatal cases of encephalitis.1 Subsequent work by Australian investigators established MVEV as the likely aetiological pathogen of the severe encephalitis “Australian X disease”.1 MVEV is enzootic in northern Western Australia and the Northern Territory, resulting in sporadic human cases.2 In south‐east Australia, however, MVEV activity can be absent for decades only to reappear with significant human outbreaks. The three most recent outbreaks in Australia were in 1951 (45 cases), 1974 (58 cases) and 2011 (17 cases).1,2,3 The case fatality rate is about 18% in hospitalised patients, reflecting the severity of disease.4
- 1. Mackenzie JS, Broom AK. Australian X disease, Murray Valley encephalitis and the French connection. Vet Microbiol 1995; 46: 79‐90.
- 2. Selvey LA, Dailey L, Lindsay M, et al. The changing epidemiology of Murray Valley encephalitis in Australia: the 2011 outbreak and a review of the literature. PLoS Negl Trop Dis 2014; 8: e2656.
- 3. Knox J, Cowan RU, Doyle JS, et al. Murray Valley encephalitis: a review of clinical features, diagnosis and treatment. Med J Aust 2012; 196: 322‐326. https://www.mja.com.au/journal/2012/196/5/murray‐valley‐encephalitis‐review‐clinical‐features‐diagnosis‐and‐treatment
- 4. Bennett NM. Murray Valley encephalitis, 1974: clinical features. Med J Aust 1976; 2: 446‐450.
- 5. Spencer JD, Azoulas J, Broom AK, et al. Murray Valley encephalitis virus surveillance and control initiatives in Australia. National Arbovirus Advisory Committee of the Communicable Diseases Network Australia. Commun Dis Intell Q Rep 2001; 25: 33‐47.
- 6. Knope K, Whelan P, Smith D, et al. Arboviral diseases and malaria in Australia, 2010–11: annual report of the National Arbovirus and Malaria Advisory Committee. Commun Dis Intell Q Rep 2013; 37: E1‐E20.
- 7. Sutherland GL, Nasci RS. Detection of West Nile virus in large pools of mosquitoes. J Am Mosq Control Assoc 2007; 23: 389‐395.
Publication of your online response is subject to the Medical Journal of Australia's editorial discretion. You will be notified by email within five working days should your response be accepted.