Arboviruses in horses – a potential concern with all this rain!

With all the recent rain we have been getting in Victoria the number of mosquitoes around has also increased. Unfortunately mosquitoes can be involved in the transmission cycle of certain viruses called Arboviruses whereby disease can be transferred to horses (and other species / humans) through an insect bite.

The main arboviruses of concern in Australia include Ross River virus, Murray Valley encephalitis virus and West Nile/Kunjin virus.

Clinical signs of arbovirus infection in horses can be non-specific and in some cases may not cause obvious clinical signs. Those affected usually present with musculoskeletal or neurological disease. Signs can include:

  • Fever

  • Muscle soreness

  • Lameness

  • Swollen limbs

  • Staggering gait

  • General depression / lethargy

  • Weakness

  • Exercise intolerance

Diagnosis of arboviruses can be complex and often requires a series of blood tests where we look for an increase in antibody numbers in the blood over a period of 2-4 weeks.

Treatment is mainly supportive with the use of anti-inflammatories to make horses more comfortable. Antioxidants and omega 3’s may also be useful.

Often the recovery for affected horses can be quite prolonged and athletic performance may be affected for a number of months.

Steps you can take to help prevent infection involves:

  • The use of fly sheets, rugs and fly masks where possible

  • Topical Insect sprays

  • Eradication of stagnant water sources on property

  • Provide fresh water in troughs

  • Avoid stabling of horses at dusk and dawn when mosquito activity is most prevalent

Ross river virus