Histoplasmosis in Cats: Symptoms, Diagnosis, and Treatment What to Do If Your Cat Has Histoplasmosis

Histoplasmosis in Cats: Symptoms, Diagnosis, and Treatment

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Histoplasmosis is a fungal infection that can affect your catโ€™s lungs, skin, and other organs. Learn more about how to diagnose and treat histoplasmosis in cats.

Histoplasmosis is a fungal infection caused by Histoplasma capsulatum. It is primarily found in 31 states across the Americas, particularly in the Mississippi and Ohio river valleys. The fungus grows in soil that is contaminated with bird or bat droppings. People can become infected with histoplasmosis by inhaling spores of the fungus. 

The infection can range from mild to severe, and it can affect the lungs, skin, and other organs. In people with a weakened immune system or who have underlying health conditions, histoplasmosis can be life-threatening. Symptoms of histoplasmosis include fever, cough, chest pain, and difficulty breathing. The infection is usually treated with cat antifungal medications.

Histoplasmosis can also infect cats, although it is not as common as it is in humans. Cats can become infected with histoplasmosis by inhaling spores of the fungus, just like humans. The infection can affect the respiratory system and the digestive system in cats.


Histoplasmosis is a fungal infection that can affect cats, as well as other animals and humans. In cats, signs of histoplasmosis can vary, but may include:

  • Fever

  • Weight loss

  • Decreased appetite

  • Depression 

  • Coughing

  • Difficulty breathing

  • Eye inflammation

  • Enlarged lymph nodes

  • Vomiting

  • Diarrhea

The symptoms of the disease usually vary according to the part of the body infected by the virus. For example, if the virus has affected the respiratory system, you will notice coughing and difficulty breathing. On the other hand, if the cat’s intestinal tract has been infected, it will show signs of decrease in appetite and weight loss. 

The signs of histoplasmosis can be subtle, and the disease can be difficult to diagnose because it can mimic other respiratory infections. If left untreated, histoplasmosis can be serious and potentially life-threatening for cats. 


The diagnosis of histoplasmosis in cats is typically based on the combination of clinical signs, physical examination findings, and laboratory test results. To diagnose histoplasmosis, the veterinarian may recommend one or more of the following tests:

  • Physical examination: The veterinarian will perform a thorough physical examination of the cat, looking for signs of illness such as fever, weight loss, coughing, difficulty breathing, and eye inflammation.

  • Blood tests: Blood tests can help the veterinarian determine if the cat has an infection and how severe it is. The veterinarian may recommend a complete blood count (CBC) and a chemistry panel to check for signs of infection and organ dysfunction.

  • Radiographs (x-rays): Radiographs can help the veterinarian see if the cat has an infection in the lungs or other organs.

  • Biopsy: If the veterinarian suspects histoplasmosis, they may recommend a biopsy of affected tissue to confirm the diagnosis. A biopsy involves removing a small piece of tissue and examining it under a microscope to look for the presence of the fungus.

The earlier the infection is diagnosed and treated, the better the outcome is likely to be.


Treatment of histoplasmosis in cats typically involves the use of antifungal medications. The specific medication and duration of treatment will depend on the severity of the infection and the overall health of the cat. Common antifungal medications used to treat histoplasmosis in cats include:

The treatment usually goes on for 4-6 weeks. In addition to antifungal medications, the veterinarian may recommend supportive care such as oxygen therapy, fluid therapy, and nutrition support. 

Additionally, the vet might prescribe immune support supplements to boost the cat’s immune system and prevent such infections in the future. Ask the vet about any specialized diet recommendations you might need to follow.

The cat may need to be hospitalized during treatment to receive supportive care and to monitor for any complications. If your cat needs to stay at the hospital for a few days, make sure you create a comfortable space for them with their favorite plush toys and other belongings.

It is important to follow the veterinarian's treatment recommendations and to give the medication as directed. If the cat is not responding to treatment or if the infection is severe, the veterinarian may recommend referral to a specialist or a different course of treatment.

The prognosis for cats with histoplasmosis is generally good with appropriate treatment, but it is important to follow the veterinarian's recommendations and to complete the full course of treatment to ensure the best possible outcome.

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