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MURRAY VALLEY ENCEPHALITIS (Contact) Please CLICK on
underlined links for details: Murray Valley
Encephalitis is a Flavivirus that is related but less viral than
the Kunjin Virus. is endemic in
northern portions of Australia and New Guinea. Earlier designations for the disease were Australian Encephalitis and Australian "X" Disease. The virus may cause neurological disease
or even death in humans. Although
endemic in Northern Australia the virus sometimes spreads to more southerly
areas during periods of high rainfall in summer. Outbreaks of the disease are spaced by decades and little or no
cases between. Mosquitoes are the vectors with a bird to mosquito to bird
cycle. Birds inhabiting aquatic areas
are the natural reservoir for the virus.
Culex annultrostris is
the principal vector, and infection can only occur through mosquito bites and
not from infected persons. EPIDEMICS Epidemics first were reported in 1917-1918 in Southeastern
Australia after several years of heavy rainfall. Virus isolation from humans was made in 1951 following an
epidemic in the Murray Valley.
Epidemic threats increase when infected birds or mosquitoes migrate
from more northerly parts of Australia.
Therefore, public health personnel in southern Australia test
"sentinel chickens" that are placed near bird breeding sites for
virus to warn of pending epidemics. CONTROL No vaccines were available as of 2017. Cover exposed parts of the body by wearing
long-sleeved shirts, a hat and long trousers. Products such as DEET, Picaridin
and Oil of Lemon Eucalyptus are
useful repellents. Clothing that is treated with Permethrin remain protective
even after several washings. For
areas with large mosquito populations it is advisable to have screened or
air-conditioned rooms. Netting is
required if sleeping outdoors. = = = = = = = = = = = = = = = = = =
= = Key
References: <medvet.ref.htm> <Hexapoda> Burnet, F. M. 1952.
Murray Valley encephalitis. Nations Health. Amer. J. Publ. Health 42(12): 1519-1521. French, E. L. 1952.
Murray Valley encephalitis isolation and characterization of the
aetiological agent. Med. J. Australia
1(4): 100-103. Hurrelbrink, R. J., A.
Nestorowicz & P. C. McMinn.
1999. Characterization of
infectious Murray Valley encephalitis virus derived from a stably cloned
genome length cDNA. J. Gen. Virol. 80 (12): 3115-1325. Matheson, R. 1950. Medical Entomology. Comstock Publ. Co, Inc. 610 p. Service, M. 2008.
Medical Entomology For Students.
Cambridge Univ. Press. 289 p Legner, E. F. 1995. Biological control of Diptera of medical and veterinary
importance. J. Vector Ecology 20(1):
59_120. Legner, E. F. 2000.
Biological control of aquatic Diptera. p. 847_870.
Contributions to a Manual of Palaearctic Diptera, Vol. 1, Science Herald, Budapest. 978 p. Marshall, I. D., B. K. Brown, K. Deith, G. P. Gard
& E. Thibos. 1982. Variation in arbovirus infection rates in
species of birds sampled in a serological survey during an encephalitis epidemic in the Murray Vally of
South-eastern Australia, Feb. 1974.
Australian J. Exptal. Biol. Med. Sci.
60(5): 471-78. |