Microsporum canis

Microsporum canis is a dermatophyte fungus that is a common cause of ringworm in animals, particularly cats and dogs, and occasionally in humans. It is one of several species in the genus Microsporum, which are characterized by their ability to invade keratinized tissue, such as hair, skin, and nails.

Characteristics

Microsporum canis is a ectothrix fungus, meaning it grows on the outside of the hair shaft. It produces macroconidia, which are large, multicellular spores that are typically spindle-shaped. The fungus is also characterized by its ability to fluoresce under Wood's lamp examination, which can aid in diagnosis.

Transmission and Infection

Microsporum canis is primarily transmitted through direct contact with an infected animal or person, or indirectly through contact with contaminated objects, such as grooming tools or bedding. The fungus can survive in the environment for long periods, making it a common cause of zoonotic infections.

Once the fungus has been transmitted, it invades the keratinized tissue and begins to proliferate, causing symptoms such as itching, redness, and hair loss. The infection is typically localized to one area, but can spread if left untreated.

Diagnosis and Treatment

Diagnosis of Microsporum canis infection is typically made through clinical examination and confirmed with laboratory tests, such as fungal culture or microscopy. Wood's lamp examination can also be used, as the fungus will fluoresce a bright green color.

Treatment typically involves topical antifungal medications, such as miconazole or ketoconazole, and in severe cases, oral antifungal medications may be prescribed. It is also important to thoroughly clean and disinfect any contaminated objects to prevent reinfection.

Prevention

Prevention of Microsporum canis infection involves regular grooming and cleaning of pets, as well as avoiding contact with animals known to be infected. In multi-pet households, it may be necessary to isolate infected animals until they have been treated.