What You Don't Know About Mosquitoes and Horses Could Hurt You.

Thinking about mosquitoes can make even the bravest of us feel a little uneasy. These blood-sucking, winged insects are a well-known nuisance but, their potential for harm doesn't stop there. In simple terms, mosquitoes transmit diseases – not just to horses but to humans and other animals too – and therefore installing effective control methods around your barn is more than just sensible – it can be lifesaving.

Why are mosquitoes a problem?

Mosquito Adult
The Mosquito

As the warmer seasons approach, the barn and surrounding area become an ideal breeding ground for mosquitoes. Within the United States. there are more than 200 species of mosquito, but only adult females actually feed on blood. The life cycle begins with eggs laid upon the surface of standing water (such as a pond or trough) which develop rapidly and hatch within 48 hours. Certain species of mosquito can take up to a month to fully mature while others reach adulthood in as little as 72 hours. Upon hatching, they are generally raring for a meal.

Mosquitoes are not easily spotted while dining. You will rarely find a mosquito actually resting on your horse, but you may instead find raised, irritated skin displaying symptoms of hives and itching where the mosquito has bitten the skin and injected a toxin, to which many horses can react. The mosquito will then feed on the blood of the horse, leaving this area itchy and susceptible to further damage when the horse rubs the wound, further enabling bacteria to reach your horse's blood stream.

The main concern, however, is the transmission of more serious illnesses through the exchange of blood and saliva in the bite. Mosquitoes are known as carriers of some of the most concerning and potentially fatal diseases in humans, such as malaria and in horses, such as: West Nile Virus and Eastern and Western Equine Encephalomyelitis (WEE /EEE).

What are the risks of these diseases?

West Nile Virus and Eastern and Western Equine Encephalomyelitis are serious conditions carried by mosquitoes and introduced into the bloodstream of the horse through bites. Signs of these largely incurable illnesses include anything from loss of appetite, fever, weakness and neurological abnormalities through to full collapse and death. Veterinarians strongly advise vaccinating against these diseases, owing to the serious nature of their prognoses and the prevalence of mosquitoes. However, even if your horse is safeguarded from these illnesses, you will still want to protect your horse from the irritation triggered by bites and the potential for allergic responses.

How can I minimize exposure to mosquitoes?

It is recommended that every horse owner in a mosquito-prone area takes measures to reduce their horse’s contact with these potentially dangerous pests. We have gathered some tried-and-tested ideas to help you get rid of mosquitoes in your barn and pasture:


  • Talk to your veterinarian about a comprehensive vaccination program. Ensure you keep up to date with boosters and on schedule to prevent spread of infection should the worst happen.
  • Bring your horse inside at dusk, when mosquitoes and other flying insects are most active, and keep him in the stall overnight during the most active mosquito month.
  • When the horse is stabled, use fans between stalls to prevent mosquitoes from biting the horse as the movement of air prevents landing.
  • Remove any areas of stagnant water around the barn, including any unemptied buckets of water in stalls that are unused, bird baths, plant pots and any holes in the ground. Any still water can be a breeding ground for mosquitoes so remove these areas of water as often as possible.
  • Mosquitoes hide in grass and around drains which tend to be damp – keep drains dried and aired out and all tall grass clipped short, so those areas are too exposed to permit mosquitoes to hide.
  • Cover over swimming and kiddie pools thoroughly, when not in use.
  • Regularly empty, clean and refill any water containers and troughs – at least every three days.
  • Invest in Spalding Mosquito Torpedoes for any area of standing water. These tablets can be safely used in drinking water for horses, so are ideal for water receptacles and ponds, and they are approved for use in stock tanks. Spalding Mosquito Torpedoes contain an insect growth regulator which stops all life stages of the mosquito, removing over 95% of the local population.
  • Invest in a fly sheet and mask for your horse to cover him during the daytime hours and prevent the mosquitoes coming into contact with the skin.

For more information on why and how to control mosquitoes, consult Spalding’s handy article on What You Need to Know About Mosquitoes to Not Have Them.