Published Date: 2011-03-13 07:00:10
Subject: PRO/AH> Murray Valley encephalitis - Australia (03): warning
Archive Number: 20110313.0804
MURRAY VALLEY ENCEPHALITIS - AUSTRALIA (02): WARNING
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: 10 Mar 2011
Source: Warren Advocate [edited]
Mosquitoborne disease sparks health warning
The mozzies may have quietened down a bit since the flooding eased
but the recent detection of Murray Valley encephalitis has sparked a
warning from health professionals.
Western New South Wales (NSW) and Far West Local Health Networks warn
residents and visitors to protect themselves against mosquitoes
following the detection of the disease found in sentinel chickens
located in the Macquarie Marshes.
Sentinel chicken flocks act as a warning system for human infection
by being regularly monitored for viruses that mosquitoes can transmit
to people and cause illness. NSW chief health officer Dr Kerry Chant
said the latest detection should serve as an important reminder for
people to protect themselves. "Positive findings in chickens are rare
in NSW. The important message is to avoid mosquito bites and be alert
to any symptoms," Dr Chant said.
"The current area of risk extends in regions west of the Great
Dividing Range and is likely to be highest around rivers, wetlands and
flooded areas. The increased risk of human cases is related to
increased mosquito breeding related to warm temperatures, heavy
rainfall and flooding."
Associate professor Tony Brown from the University of Sydney School
of Rural Health said MVE [Murray Virus encephalopathy] is rare and
there have been no human cases detected since 2008 in NSW. In that
instance MVE was detected in someone who lived near the Macquarie
Marches and that person recovered.
"Most people who contract MVE will not develop symptoms, but it is a
serious mosquitoborne disease," said Dr Brown. He said in mild cases,
MVE symptoms can include fever, headache, nausea and vomiting and
muscle aches. In more severe cases symptoms can include neck
stiffness, lethargy, drowsiness, confusion, delirium, tremors,
neurological problems and coma in severe cases. "People with these
symptoms should immediately seek medical assistance," said Dr Brown.
"Parents concerned about a child with fever, should see their doctor
and especially if their child has convulsions, drowsiness, floppiness,
irritability, poor feeding or general distress."
Simple steps to avoid being bitten by mosquitoes include:
-- when outside cover up as much as possible with light-coloured,
loose-fitting clothing and covered footwear;
-- use an effective repellent on all exposed skin. Re-apply repellent
within a few hours, as protection wears off from perspiration,
particularly on hot nights. The best mosquito repellents contain
diethyl toluamide (DEET) or picaridin;
-- the stronger the concentration of an insect repellent, the less
frequently it will need to be applied to stop mosquito bites.
Repellents containing low concentrations of DEET or picaridin provide
shorter periods of protection and need to be reapplied more frequently
so it's important to read the product information;
-- topical repellents are not recommended for use on children under 3
months. Use of physical barriers such as netting of prams, cots, and
play areas is preferred. Repellents containing less than 10 per cent
DEET or picaridin are safe for older children if applied according
instructions. Parents or carers should apply repellent;
-- light mosquito coils or use vapourising mats indoors. Devices that
use light to attract and electrocute insects are not effective.
-- cover all windows, doors, chimneys, vents, and other entrances
with insect screens;
-- when camping, use flyscreens on caravans and tents or sleep under
[With Ross River Virus and Murray Virus encephalopathy in the area,
it is important to take precautions against mosquitoes. There are
mosquito and fly repellants available for horses, which should be
Horses are often sensitive sentinels for mosquitoborne diseases, as
are birds. Clearly there are horses affected. The article mentions
sentinel birds but it is not clear if these birds have shown titers or
have shown signs of the disease.
The HealthMap/ProMED-mail interactive map of Australia can be seen at
<http://healthmap.org/r/0zHG> â Mod.TG]