Mosquito risks

pet advice

Mosquito risks

words by
catherine harper // Barossa Veterinary clinic

Mosquito numbers are still at high levels across the state compared to previous years.  SA Health has reduced its hierarchy of response to threat level two (medium).*

Numbers have reduced since the flooding of 2022/23, yet there are still many mosquitoes around.  While there is good publicity around the risks to human health, mosquito-borne diseases can also affect our animal companions.  Therefore, improving awareness and options for prevention for our animal friends is an important topic.

There are two classes of disease that are spread by mosquitoes and are of concern in our area. 

The first are viruses: Japanese encephalitis virus, West Nile virus, Ross River virus and Murray Valley Encephalitis virus.  These are carried by mosquitoes and can infect many species of animal but cause severe disease in pigs and horses. 

We have seen several cases of these viruses in the Barossa and Mid North in the past 12 months and while all the animals are recovering, for some, the recovery period has been protracted.  Signs to look for include fever greater than 38.5 degrees Celsius, lethargy, reduced appetite, neurological signs – appearing wobbly, reduced vision etc.

If you have any suspicions, then a visit from a vet is essential to assess, diagnose and treat. Diagnosis is via a blood test and, if positive, will be reported to PIRSA for ongoing disease monitoring. 

Treatment centres (for) supportive care and your veterinarian will be able to guide you through this process.  If your horse is positive, then there is a chance that you may have been exposed and talking to your GP about risks and any follow up is recommended as a vaccine is available for humans. 

Prevention is based on reducing exposure, which can be achieved using permethrin-based sprays, a light cotton rug, stabling at night, minimising any areas of standing water (puddles, gutters, unnecessary water sources) and hosing at dusk and dawn to reduce mosquito landing.  There is additional information available at https://pir.sa.gov.au/

Another mosquito borne disease of concern is heartworm. Heartworm is a disease of dogs and occasionally cats.  While there is a low risk of disease in South Australia, with road travel back on the agenda post COVID, there are many animals from the eastern states where the disease is much more prevalent, moving through our wonderful tourist region. 

These animals may be carrying disease and with increased numbers of mosquitoes around, there is a higher risk of spread.  Detection of heartworm is less obvious than the above viruses, but can involve coughing, lethargy, weight loss and reduced exercise tolerance.  Heartworm is easily prevented with either an annual injection or monthly chewable tablet. Your local vet will be able to provide the best advice on the best preventative option, so drop in and ask. 

While none of these diseases are currently occurring in high numbers, being aware of them and the risks mosquitoes present is valuable in helping in prevention and early detection. 

*Correct as of March, 2024.

Catherine Harper


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