The Classic Comprehensive Handbook of Cat Care: TROMBICULID MITES (CHIGGERS)
Trombiculid mites (chiggers, harvest mites) are red, orange, or yellowish mites that have larvae that feed on the tissue fluids of cats and other mammals. (The nymphs and adults feed on plants or invertebrates.) The larvae are often found on the head and neck, particularly in and around the ears, but can infest any part of the body, causing scratching which is sometimes very severe. Look for red, orange, or yellowish specks about the size of the point of a dressmaker’s pin in affected areas. Use a magnifying glass if necessary.
If you cannot find the mites, diagnosis may have to be made by an examination of a skin scraping performed by a veterinarian. Mites found solely in the ear can be eliminated by the treatments for ear mites. Mites on other body areas can be controlled with dips or other preparations effective against head mites. Prevent reinfestation by keeping your cat indoors, away from woodsy semiwild areas where the mites are found most often.
Adult flies are not normally parasitic on cats. Some types of adult flies lay their eggs in raw or infected wounds. When the eggs hatch, the maggots feed on the tissue present, producing a condition called myiasis.
Maggots are frequently found in infected ears as well as in neglected skin wounds and under matted hair. To treat myiasis, all the maggots must be removed manually, the areas washed with an antibacterial soap (e.g., povidone-iodine), and a topical antibiotic cream or ointment applied to treat any secondary bacterial infection that may be present. It is extremely important to treat the predisposing condition or myiasis is likely to recur.
A particular kind of bot fly of the Cuterebra species, whose maggot (larva) is a natural parasite of rodents, may occasionally infest cats that snoop around rodent burrows. These larvae penetrate the skin, then become surrounded by thickened tissue and are connected to the skin surface by a breathing pore. These areas are often found on the head and neck and sometimes they become infected, causing an abscess to form.
Removing the maggot from the pocket will cure the problem. This can be done by gently enlarging the pore with tweezers and carefully removing the whole larva. Crushing the larva can cause a serious allergic reaction, so if you suspect Cuterebra infections in your cat, you should consider contacting your veterinarian for help.