Ringworm, or dermatophytosis, is an infection of the most superficial layer of the skin with a fungi, usually (98% of the time in cats), a species called, Microsporum canis.
It is very contagious and infection is spread by direct, or indirect, contact.  Infected cats shed fungal spores which can live in the environment for a year.  It is a very common problem in Persian cats. In fact,  Dr. Steven A. Melman, author of Skin Diseases of Dogs and Cats, has ringworm listed under Persian cat in his table describing "Breed Predilection for Skin Diseases!" (Table 2.3, page 36).  In his book, Dr. Linda Medleau (who wrote the section on ringworm), describes non-symptomatic carrier cats that harbor "sub clinical" infections as a source of infection to younger, more susceptible cats.

Skin scrapings for cultures are the most reliable method of diagnosis since not all species of fungi fluoresce under the ultraviolet Wood's lamp that is sometimes used as an aid in diagnosis.  A Wood's lamp is helpful for catteries where M. canis is the known cause as it allows for a quick check on the progress of treatment in a large number of cats.  It also may aid in checking the thoroughness of any disinfecting routine.

Shaving the cats with a #10 (surgical A-5 clipper blade) is recommended, as well as isolation techniques, if possible.  This allows the medication to get down to the site, and stops the shedding of infected hairs (the spores).

Since many cats can have the disease and not show any symptoms, it's best to treat all the cats.  Many references say to isolate infected cats.  My opinion is that all cats are potentially infected and should be treated as if they are.

Wash the cat with Micro-Tek Shampoo leaving it on him for at least 5 minutes, then rinse.  Then dip the cat in the Lyme Sulfur dip. OR if the cat's coat is too light-haired and it will be stained THEN

Wash the cat with Miconozole shampoo leaving it on at least 5 minutes (10 is better but bordering on ridiculous), then dry the cat thoroughly and spray the cat with the LymDyp-S spray.

A few veterinarians will recommend systemic treatment with Fulvicin (grisofulvin) given orally.  It causes birth defects if given to pregnant queens.  It has numerous other side effects such as bone marrow suppression, liver and kidney damage, and  loss of appetite to name a few.  Even the healthiest cats can have difficulty tolerating treatment with Fulvicin.  There are other drugs, like Nizoral, Diflucan, and Sporonox that can be prescribed but also have side effects.  This decision needs to be made by you and your vet.

If you don't wish to rip your carpet out, then vacuuming daily and throwing the bag away is recommended.  Always color-fast test your carpet before applying any treatments, but Health Guard Laundry Additive (ViBAX-5) can be mixed as a spray and sprayed on the carpet.  DC3 (Triple Jet) Dyna-Fog Hurricane Fogger can be used to fog a carpeted room with a disinfectant, hopefully, one that is color-safe and non-staining!

Ft Dodge makes a ringworm vaccine called Fel-O-Vax MCK.  It is killed Microsporum Canis.  It can be given to healthy cats that are at least 4 months of age as an aid in the prevention and treatment of ringworm.  It is given subcutaneously, repeated in 12 to 16 days, then repeated again 26 to 30 days following the 2nd dose for a total of three injections.  The cost is about $10.00 per injection if you buy the vaccines in bulk through a mail-order catalog and administer it yourself (costs include 1st day air shipping of the vaccines).  Some breeders recommend dividing the vaccine up and injecting it into two sites since the vaccine tends to cause severe local skin reactions, often causing large abscesses.
 
 

Weapons in the Battle Against Ringworm

SHAMPOOS	DIPS	TOPICAL THERAPY	NUTRITIONAL THERAPY	ENVIRONMENTAL DISINFECTANTS
Micro-Tek Pet Shampoo by EQyss  Formulated to stop scratching and itching.  Contains Microban.  Is soothing.	LymDyp (lime sulfur)  Alternate this dip treatment with a ringworm shampoo.  Dip one day, then shampoo the next.  Kills the fungus.  May stain light haired cats.	Micro-Tek Pet Spray by EQyss A spray that stops scratching and itching.  Can be used with either Micro-Tek or Miconozole shampoos.	Derm Caps by DVM  One capsule per 20 lbs of weight per day.  Contains Vitamin E and linoleic acid (oils that are good for the skin).	Chlorine Bleach diluted 1 part bleach to 10 parts water.  Use to wipe down surfaces and wash the floors.  If you have carpet and want to get rid of ringworm, my advice is to rip it out and have flooring installed!
Miconozole shampoo by Micro Pearls Contains Miconazole Nitrate 2% anti-fungal shampoo.	LymDyp-S (3% Sulfurated lime solution)  Sprayed and left on at 5 to 7 day intervals.  Bathe prior to using.  Kills the fungus.	Topical Fungicide by Animal Health Controls ringworm and itching.  Spray affected areas, leave treated areas uncovered.	3V Caps by DVM  One capsule daily.  Contains concentrated Fish Oil and Omega-3 polyunsaturates plus Vitamins A, D, & E.	ViBAX-5 Laundry additive and disinfectant.  May also be used to clean floors, walls, cages, kennels, and surfaces.  Add 1 teaspoon  to the rinse cycle for small loads, 1 tablespoon for large loads.

Drs. Foster & Smith, Veterinarian-Selected Products for Dogs & Cats
J-B Pet Supplies Homepage
KV Vet Supply
Omaha Vaccine Company - 1 800 367-4444
Drs Foster & Smith - 1 800 826-7206
Revival Animal Health - 1 800 786-4751 - Great Ringworm Products
New England Serum Company - 1 800 637-3786
R.C. Steele - 1-800-872-3773