Harvest mites are tiny animals living in dense vegetation, that eat plants and even tinier insects. However their bright orange larvae feed on mammals, frequently causing skin irritation.
On warm days in late summer until the first frosts of winter, they climb up long grass and bushes waiting for something warm-blooded to pass! When they get the chance they jump on and swarm over the mammal’s body to find an area where the skin is thinnest, before sinking their hooked fangs in. They feed by injecting a fluid into the deeper layers of the skin. This liquefies the surrounding cells and the resulting ‘goo’ is sucked back into the mite. They will feed for 2 – 3 days, enlarging in size from 0.2mm to 0.6mm as they do so. They can just be seen by the naked eye as orange dots. After feeding they drop to the ground where they develop into adults via a nymph stage.
The mites tend to principally affect cats, although humans, rabbits and dogs can also get them. They can cause very few problems, but sadly a lot of animals become allergic to the fluid injected by the mite, resulting in reddening and crusting of the skin. Often the animal will then scratch at the mites, worsening the inflammation and introducing bacterial infection.
The mites tend to attach just in front of the ears, at the base of the ear flap or between the toes. Less frequently the chin, lips, armpits and tummy can suffer.
If your cat, dog or rabbit is affected by harvest mites they may require antibiotics and steroids to settle the inflammation, so a visit to the vets for a check up is advisable.
To prevent mites attacking your pet, a spray containing the insecticide fipronil can be applied to susceptible areas every 2 weeks during the harvest mite season – late July to early October. You can either spray it straight on to the coat and feet, or for the face and ears, spray it onto your gloved hand and then rub it on. (Do wear gloves.)
As the mites live in long grass and vegetation, keeping your grass short and borders weed-free can help reduce the chance of picking them up – depending on how far your cat travels! Very sensitive animals may need to be kept confined during the worst months, particularly on bright, sunny days during late morning and afternoon when the mites are at their most active.