What do you first think of when you hear “ringworm”? Most likely, you think of a worm in the skin. However, ringworm isn’t really a worm at all. It is a fungus, commonly in the shape of a circle, or “ring”.
Here is the typical appearance on a calf.
The official medical term is dermatophytosis (der – mat- o – fi – toe – sis). It is an infection of the skin, hair, or claws (nails) by a fungus. All domestic animals are susceptible to this disease, but it is most commonly seen in cats and cattle. It is a zoonotic disease, which means is can be transmitted between people and animals.
Most ringworm infections are self-limiting. This means once the body adapts, the ringworm will clear without any treatment. Some animals can be chronic carriers and continually spread the disease to others, especially from cats to children.
Animals infected with ringworm should be decontaminated and separated from other animals until they are clear from disease. This limits spread. Barn cats are notorious for spreading it to horses, especially when brushes are left lying around. The cats will rub against the brushes, then the horses get groomed with those same brushes. Instant contamination and spread throughout the barn.
Treatment options include dips, sprays, and sunshine. Good nutrition will limit infection by boosting the animal’s own immune system. Ringworm is common in the cold, wet winter months because that’s a good environment for fungal growth. Summer sunshine is a great treatment.
Some useful sprays are 4% lime sulfur dip (which smells terribly of rotten eggs), 1% iodine solution (iodine will stain your clothing, so be careful), or a 0.5% chlorhexidine solution. All of these can be mixed and sprayed onto cattle. Cats need to be dipped into a small container – they tend to tolerate being “dipped” (do not submerge the head – only up to the neck) much better than being sprayed. You will need to watch the cat so that it dries before it begins to groom that preparation and ingests too much of it.
Cats and dogs may both be prescribed an oral or topical anti-fungal medication.
The primary things you need to know about ringworm are:
1 – It is not a worm – it’s a fungus
2 – It is a contagious, zoonotic disease. Prevent spread between animals and people. (This means wear gloves, wash hands, clean grooming equipment, and treat any people with lesions.)
3 – It requires a warm, moist environment to flourish. Be sure animals are clean and dry.
4 – Sunshine is nature’s disinfectant. Lay things out in the sun if you are worried about contamination.
5 – Clean all hard surfaces, bowls, and shared items with dilute (1:10 dilution) of household bleach. This also kills ringworm.
Have a ringworm-free spring!