Mosquito borne disease alert
PIRSA is reminding horse owners to be alert for the clinical signs of mosquito borne diseases, such as:
- Murray Valley encephalitis virus (MVEV)
- Japanese encephalitis virus (JEV)
- West Nile virus-Kunjin strain (WNV-KUN).
Detections
Ttest results between January and March 2023 suggested some horses may have been infected with MVEV or JEV. There have been sporadic reports from these regions:
- Mount Lofty Ranges
- Adelaide Plains
- Gawler
- Barossa
- Mid North.
Further testing is being undertaken which may assist our understanding of these test results.
Flaviviruses
Sentinel chickens are used as an indicator of mosquito borne disease risk as they produce antibodies when exposed to these viruses without showing any symptoms.
Through the SA Health arbovirus monitoring program, antibodies were detected in sentinel chicken flocks as follows:
- for MVEV in the Riverland and Clare regions
- for WNV-KUN in the Clare region.
This indicates that flaviviruses may be circulating in the environment, prompting warnings to be alert and minimise exposure of horses to mosquitos where possible.
Mitigation strategies
Try these methods to minimise mosquitos:
- Use mosquito repellent.
- Cover horses or keep them indoors during high mosquito activity – particularly at dawn and dusk.
- Eliminate mosquito breeding areas on your properties.
See more information about managing mosquitoes to reduce the risk of viruses.
Signs of disease
Horses infected with mosquito borne viruses will not always show signs of disease. Clinical signs are primarily neurological and may include:
- staggering
- incoordination
- weakness
- depression
- decreased or no appetite.
Neurological signs can occur with many other diseases, including Hendra virus. It is important to follow biosecurity practices when checking on your horses.
As Hendra can be fatal to both horses and humans, you must wear personal protective equipment and practice good hygiene when interacting with horses displaying such signs.
If your horse appears unwell
If you notice that your horse is unwell, contact your veterinarian to arrange for an examination and possibly laboratory testing.
Veterinarians should contact their local PIRSA veterinary officer for testing protocols and guidelines. JEV and WNV-KUN are notifiable diseases in animals in South Australia, any suspicious neurological cases and must be reported to the EAD hotline.
