First floods, then pestilence
Within the next couple of days I would expect most of the area who had received some waterlogging to become a swarming mass of mosquitoes, sand flies, March flies and midges. Particularly anywhere along the river or creeks which flooded. Your pets are equally as uncomfortable dealing with biting insects as you are. However we can help to protect them. Dogs and horses can be protected using insect repellents that are registered for their use. Repellents include pyrethrin based insecticides and repellents which include similar ingredients to human insect repellants. Registered products include Repel-x, Muscaban, Flygon and others. Unfortunately there are very few products available that have been registered for use on cats.
To this end, please be very careful when applying anything to cats. Cats are extremely sensitive to the toxic effects of synthetic pyrethrins and DEET. A single limited exposure can cause seizures and death. The ingredients in Rid and Aerogard are generally safe to use topically on pets as long as there is no DEET in the ingredients list. However cats usually don't like the smell or the taste on the skin. Dogs can be protected with these (which is considered “off label” usage) but the ingredients are safe for them in general. Repellants need to be applied at least twice daily to be effective. Apply to the head using a sprayed cloth.
Horses have a number of registered products that you can use at least twice daily to have a repellent effect. There are also longer acting products available that you can use that kill insects but unfortunately these don't stop the insects from biting your horse first. Registered products for horses include Permoxin Spray, Repel-X, Flygon, Swift, Brute and numerous others. Horses can be partially protected using rugs and fly masks to protect their skin, some of which now include insecticides permeated into the material.
Some pets can have allergic reaction to both mosquitoes, sandflies, midges and March Flies. Giving a fish oil supplement orally with food may reduce allergic reactions. Sometimes they need prescribed medication either or both topically and orally to keep them comfortable. Secondary infections at bite sites are common. Obviously confinement inside during the worst times of the day (dusk and dawn) and during the night can help cats and dogs but this is not always practical.