Murray Valley encephalitis in Western Australia in 2000, with evidence of southerly spread
DOI:
https://doi.org/10.33321/cdi.2000.24.65Keywords:
Murray Valley encephalitis virus, Kunjin virus, arbovirus, mosquito control, outbreakAbstract
We describe the epidemiological and clinical features of human Murray Valley encephalitis (MVE) and Kunjin (KUN) virus infections in Western Australia (WA) during March to July 2000. A case series was performed. For laboratory-confirmed cases, travel histories and clinical details were collected from patients, family members, friends or treating physicians. Surveillance data from the sentinel chicken program and climatic conditions were reviewed. Nine encephalitic cases of MVE were recorded. Eight were non-Aboriginal adults (age range, 25 to 79 years; 5 male, 3 female) and 1 was an Aboriginal boy. Four cases acquired infection in the Murchison and Midwest regions of WA from which no human cases of MVE have been reported previously. One of the 9 cases was fatal and 3 had severe neurological sequelae. Five non-encephalitic infections were also recorded, 3 MVE and 2 KUN. Encephalitis caused by MVE virus remains a serious problem with no improvement in clinical outcomes in the last 25 years. Excessive rainfall with widespread flooding in the northern two-thirds of WA provided ideal conditions for mosquito breeding and favoured southerly spread of the virus into new and more heavily populated areas. Surveillance in WA with sentinel chickens and mosquito trapping needs expansion to define the boundaries of MVE virus activity. To enable timely warnings to the public, and to institute mosquito control where feasible, continued surveillance in all Australian areas at risk is indicated. Commun Dis Intell 2000;24:368-372.
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References
Bennett NM. Murray Valley encephalitis, 1974: clinical features. Med J Aust 1976;18:446-450.
Mackenzie JS, Lindsay MD, Coelen RJ, Broom AK, Hall RA, Smith DW. Arboviruses causing human disease in the Australasian zoogeographic region. Arch Virol 1994;136:447-467.
Holland J, Smith DW, Broom AK, Currie B. A comparison of seroprevalence of arboviral infections between three Northern Territory regions. Microbiology Australia 1994;15:A105.
Smith DW, Broom AK, Wallace MJ. Prevalence of antibody to Murray Valley encephalitis virus in Aboriginal communities in the Kimberley region of Western Australia in 1995. Arbovirus Research in Australia 1997;7:65.
Mackenzie JS, Smith DW, Broom AK, Bucens MR. Australian encephalitis in Western Australia, 1978-1991. Med J Aust 1993; 158:591-595.
Burrow JN, Whelan PI, Kilburn CJ, Fisher DA, Currie BJ, Smith DW. Australian encephalitis in the Northern Territory: clinical and epidemiological features, 1987-1996. Aust N Z J Med 1998;28:590-596.
Hawkes RA. Murray Valley encephalitis and related infections. In: Porterfield JS, editor. Exotic viral infections. London: Chapman and Hall; 1995:175-181.
Lee DJ, Hicks MM, Debenham ML, et al. The Culicidae of the Australasian region. Volume 7. Canberra: Australian Government Publishing Service; 1989.
Mackenzie JS, Broom AK, Hall RA, Johansen CA, Lindsay MD, Phillips DA et al. Arboviruses in the Australian region, 1990 to 1998. Commun Dis Intell 1998;22:93-100.
Smith D, Mackenzie J, Broom A, Fisher D, Williams M, Burrow J et al. Preliminary report of Australian encephalitis in Western Australian and the Northern Territory. Commun Dis Intell 1993; 17:209-210.
Hall RA, Broom AK, Harnett AC, Howard MJ, Mackenzie JS. Immunodominant epitopes on the NS1 protein of MVE and KUN viruses serve as targets for a blocking ELISA to detect virus-specific antibodies in sentinel animal serum. J Virol Methods 1995;51:201-210.
Tanaka M. Rapid identification of flavivirus using the polymerase chain reaction. J Virol Methods 1993;41:311-322.
Broom AK, Mackenzie JS, Melville L, Smith DW, Whelan PI. Sentinel chicken surveillance program. Commun Dis Intell 2000;24:222-223.
Broom AK, Lindsay MD, Johansen CA, Wright AE, Mackenzie JS. Two possible mechanisms for survival and initiation of Murray Valley encephalitis virus activity in the Kimberley region of Western Australia. Am J Trop Med Hyg 1995;53:95-99.
McMinn PC, Carman PG, Smith DW. Early diagnosis of Murray Valley encephalitis by reverse transcriptase-polymerase chain reaction. Pathology 2000;32:49-51.
Hawkes RA, Pamplin J, Boughton CR, Naim HM. Arbovirus infections of humans in high-risk areas of south-eastern Australia: a continuing study. Med J Aust 1993;159:159-162.
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