2021 - THE SENTINEL

Chickens are used as an indicator of which mosquito borne disease is in the region. Here in the Kimberley there is the possibility of Ross River Virus, Murray Valley Encephalitis and Kunjin Virus. Mosquitoes are attracted to the fleshy combs on the chickens’ heads and come to feed. As a mosquito feasts on the chicken, it infects the chicken with any virus it may be carrying. The chicken’s immune system recognises the viral threat and begins producing antibodies against the virus.

‘This has no effect on the chicken, and you can still even eat their eggs. Lots of people ask me this.’ explains Chicky.

The Department of Health supplies the chickens, with flocks in communities from Kununurra across the Kimberley and all the way down to the south west. At the beginning of each year Chicky receives flocks of six-week-old female chickens which have been especially bred so they have not been exposed to any virus. During the wet season they are bled every two weeks and in the dry season monthly.

‘A tiny amount of blood is taken with a syringe from a vein in the chicken’s upper wing, and it is sent to be analysed in Perth. Chickens are the best indicator.’ explained Chicky.

Any positive results are checked. If a chicken tests positive for the antibodies she is no longer on guard duty, as each time her blood is tested, it will always come back positive regardless of whether the virus is present. She remains with the flock but is retired from having any further tests.

The Department of Health notifies other relevant authorities if a virus is detected, and warnings are relayed to travellers, clinics and shires.

My Ross River Virus symptoms were very strong, and I woke one morning not being able to walk very well. My feet felt broken and swollen, and two fingers were very painful. Previously a rash had appeared over my body, and it only took 14 days from the time I was bitten by the mosquito that my symptoms appeared. My GP recognised the symptoms of Ross River Virus immediately and a blood test confirmed it. For five months my feet felt broken and swollen, with quite a bit of pain. I did not have the lethargy many people suffer so that was lucky for me.

Here is some info about each virus that you can get from a mosquito bite:

Ross River Virus

Ross River virus causes inflammation and pain in multiple joints (epidemic polyarthritis). The symptoms may include fever with joint pain and swelling which may then be followed in one to ten days by a raised red rash affecting mainly the trunk and limbs. The rash usually lasts for one to ten days and may or may not be accompanied by a fever. The joint pain can be severe and usually lasts two to six weeks. Some people, especially children, may become infected without showing any symptoms. Most people become unwell within three to 11 days after being bitten by an infectious mosquito. There is no specific treatment for this virus.

Murray Valley Encephalitis

MVE virus usually infects people without producing apparent illness. It may also cause a comparatively mild illness. A very small proportion of those infected develop a severe brain infection called encephalitis.

Symptoms of MVE usually appear five to 28 days (average 14 days) after being bitten by an infected mosquito. The early symptoms include:

• headache

• fever

• nausea and vomiting

• muscle aches

Symptoms can progress to drowsiness, confusion, seizures or fits (especially in young children) and in severe cases delirium, coma and death. Some who recover are left with ongoing problems such as deafness or epilepsy. Anyone with the above symptoms should seek immediate medical advice. A blood test is available to test for recent or past MVE infection.

Kunjin Virus

Symptoms of Kunjin virus disease vary. The vast majority of infected people do not develop any symptoms. A small number of people may experience a mild illness with symptoms including fever, headache, muscle pain, swollen lymph nodes, fatigue and rash. Some of those people may experience inflammation of the brain, known as encephalitis. Symptoms of encephalitis may include confusion, drowsiness and seizures (fits). Those with encephalitis will usually require hospitalisation.

Prevent mosquito bites.

Many mosquitoes bite around dusk and dawn, but some can bite day and night. The only way to prevent mosquito-borne disease is to avoid being bitten. So, 3 things - cover up (clothes), repel, (mossie repellent), clean up (no areas of stagnant water around your premises).