Sentinel chickens put Kunjin virus on the radar

8 March 2011

Results of recent testing of sentinel chickens in the Top End have shown evidence of circulating Kunjin virus (KUNV) - which has a range of unpleasant and potentially serious symptoms.

"Five sentinel chickens showed positive to Kunjin virus in the Leanyer flock in Darwin, which is relatively close to a large population centre," Department of Health Director of Entomology Peter Whelan said.

"We're again urging residents and visitors to the NT to cover up and protect themselves for the next three months against mosquito bites."

The warning is being issued to reduce exposure to mosquito borne diseases, including Murray Valley encephalitis virus (MVEV), Kunjin virus (KUNV), Ross River virus (RRV) and Barmah Forest virus (BFV).

"Last week mosquito control was carried out in the Lee Point area where a large mosquito breeding site was detected," Mr Whelan said.

"The nearby Leanyer swamp is also believed to be a possible site for both mosquitoes and the water birds which are a source of the Kunjin virus.

"Three sentinel chickens were also positive in the Beatrice Hill flock and one at Nathan River, which indicates widespread Kunjin activity across the Top End.

Recent rainfall patterns in the NT indicate a high probability for both MVEV and KUNV in the Barkly and further north for all the Top End.

To avoid mosquito borne disease, residents are urged to use personal mosquito protection, and avoid being outdoors near flooded areas or places where mosquitoes are active, especially after sundown from now until June.

Rain filled containers are prime domestic mosquito breeding grounds and need to be tipped out and stored under cover. Roof gutters need to be cleaned of debris to ensure they are free draining. Rainwater tanks should be inspected to ensure they are sealed against mosquito entry.

Flooded areas of organic pollution including areas of septic contamination should be drained as much as possible, with remnant pooling treated with methoprene pellets or the new mosquito larvicide surface film.

Infection with KUNV can cause symptoms that are similar to RRV, such as swollen and aching joints, fever, headache and rash, with headache usually more pronounced than RRV. However in rare cases, KUNV can cause more severe symptoms which include severe headache, neck stiffness, fever, and delirium.

Symptoms most commonly associated with RRV and BFV disease include painful or swollen joints (particularly in the hands, ankles and knees), sore muscles, aching tendons, skin rash, fatigue, fever, headache and swollen lymph nodes. These symptoms usually last a few weeks to a few months but can last longer. Children are generally less affected by RRV disease than adults, and tend to recover quicker.

MVEV symptoms can include severe headache, high fever, drowsiness, tremor, seizures (especially in young children), and in some cases the disease progresses to delirium, coma, permanent brain damage or death. In young children, fever might be an early sign. If the child also has drowsiness, floppiness, poor feeding or general distress, parents should consult a doctor.

People do not need to alter their plans to visit the NT, but it is important to avoid mosquito bites by taking a few simple steps, such as:

  • avoid outdoor exposure around dusk and at night, near rivers and areas of dense vegetation as well as other areas of high mosquito activity
  • consider bifenthrin insecticide barrier treatments from pest control companies for use around residential grounds
  • regularly search the yard for water pooling or containers holding water. Drain and store containers under cover, or turn over, dispose of or treat with methoprene insecticide pellets or liquid mosquito surface film
  • use mosquito proof accommodation and camping facilities at night
  • wear protective light coloured clothing with long sleeves, long trousers, and ankle protection with socks, between dusk and dawn in areas where mosquito bites are likely
  • use a protective repellent containing 20% DEET or picaridin when outdoors at night in areas of mosquito activity, ensuring directions for use and application on the label are followed
  • use other mosquito protection devices such as mosquito lanterns or insecticide pads or coils as a supplement to protective clothing in exposed situations such as patios or verandahs
  • ensure children are adequately protected against mosquito bites

Media Contact: Bridget Wild                      89 992 751   or   0431 619 902