Summarize this article in one sentence.
Unfortunately, there is not an insecticide created to specifically treat a harvest mite infestation. However, your vet can effectively use a insecticides formulated for fleas instead.  Some insecticides may be administered orally, while others may be used topically. Your vet may use spot-ons (a topical liquid treatment), sprays, dips, shampoos, flea collars, oral medications or injections. In cats who are particularly sensitive, anti-inflammatory medications may be given to help reduce swelling and inflammation. Your vet may provide this medication in the form of a pill or an injection, in most cases a corticosteroid. Scratching the infected area can result in secondary skin infections. If this is the case for your cat, your vet may recommend the use of antibiotics. Your vet may provide this medication in pill-form or as an injection.

Summary:
Administer insecticide. Provide anti-inflammatory medication. Treat infections with antibiotics.