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Feline fungal infection

There are several different fungal infections in cats and the most common of them isMicrosporum canis, which accounts for more than 90% of infections. There are other causesTrichopython,Epidermophytonand other fungi belonging to the Microsporum genera. As a rule, the source of infection is the cat, but it can also be transmitted indirectly through, for example, brushes, toys and the environment. Because the infection can be transmitted between animal species and humans, it is a zoonosis. Fungal infections are significantly more common abroad than here in Finland, and they are not treated in the same way. 
A fungal infection in a cat does not necessarily cause any symptoms, or the symptoms can be very mild, but when the symptoms are most severe, the cat develops a strong skin infection, which can spread all over and cause the cat to lose its fur even permanently. Some cats recover spontaneously without treatment, but due to the risk of infection, each case should be treated appropriately. 

The best way to diagnose a cat is to do a fungal culture and possible PCR confirmation, which is most commonly taken from the cat with a toothbrush in the form of a hair sample, but it is also possible to take a surface sample from the environment. It may take several weeks to get a culture result, because some fungal strains grow slowly or, for example, washing or medicating the cat before taking the sample can slow down the growth or even prevent it completely. The so-called Wood's lamp can also be used to confirm the diagnosis, because many fungi are fluorescent, however, the method is imprecise and does not guarantee a negative result. Microscopy of the sample also does not give a more accurate result, therefore it is always a good idea to send the suspicions for cultivation. 

The treatment of fungal infection is long-term and takes a long time depending on how many animals are to be treated and what kind of environment the animals live in. . Merely treating a confirmed sick cat will not help either, but every cat in the household must be treated, as well as other symptomatic animals and people in the household should be treated at the same time and the environment should be cleaned effectively enough. Sometimes it is even impossible to get rid of the infection, because the environment cannot be washed and cleaned effectively enough. 

In the care of a long-haired cat, it is easier if the fur is shaved, it also reduces the number of fungal spores. Shaving is best done in an area that is easy to clean, which makes it easier to collect and dispose of the hair. This is preferably done by burning. Shaving should be done carefully because broken skin worsens the inflammation and you should protect yourself with protective clothing and disposable gloves. Short-haired cats do not need to be shaved. 
It would also be good to wash the cat (in the past, Malaseb shampoo was recommended, but sometimes it is difficult to get. Nizoral or Imaverol, for which you also need a prescription, are fine for this) twice a week, along with other treatment, for the entire treatment period, which usually lasts 4-12 weeks. During that time, it would also be good to use moisture drops that protect the cat's eyes from possible shampoo splashes. During the treatment period, the pet should stay in a limited, easily cleanable space such as the bathroom, and everything that has been in contact with the cat should be disinfected or disposed of because of fungal spores. The surfaces must also be wiped at least twice a week after vacuuming. For cleaning, you can use, for example, Virkon or Oxivir. The dust bag should be disposed of after each vacuuming (preferably by burning) and the vacuum cleaner should also be cleaned, the textiles should be washed at least at 60 degrees or soaked with the cleaning agents mentioned above.
The cat also needs a sedative, which is always decided by the attending veterinarian. Itraconazole (trade name Itrafungol) is the drug primarily intended for fungal treatment for cats, but some fungal strains can be resistant to the drug. Cats usually tolerate medication well. 


It is possible to take a control sample one week after the end of the treatment period. If the sample comes back positive, the treatment must be continued and the latest sample must be taken after one month at the earliest. Only two negative samples taken every month indicate the success of the treatment.

​Take your pet to the vet if...

  • the result of the culture sample is positive

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