Dogs become infected when they inhale the Coccidiodesfungal spores in dust. Dusty areas such as the deserts of California, Utah and Nevada have the highest concentration of infections, but it has also been seen in parts of Washington and Oregon. (Coccidiodes is also present in Central and South America). Often these infections will occur when it rains after a long drought, which disrupts the dusty ground and releases fungal spores into the air.
Although it is estimated that as many as 60% of animals may actually inhale these spores with no consequences, the other 40% may develop infection. Approximately 3 weeks after inhaling the spores, coughing may begin, followed by fever, loss of appetite, and weight loss.
Mild cases cause a cough, while more severe cases might lead to pneumonia or even fungal infection that spreads throughout the body. The lymph nodes in the region of the lungs can become calciified/mineralized.
Because the severity of infection and spread throughout the body is so variable, clinical signs can range from mild to fatal. In dogs, you may see a chronic cough, anorexia, cachexia (severe muscle wasting and emaciation), lameness/limping, swollen joints, fever, and diarrhea.
If you note any of these signs in your dog and you live in the Southwest or have recently traveled there, have your dog seen by a veterinarian. X-rays of the chest may be performed to look at the lungs and look for enlarged pulmonary lymph nodes. Blood work to look for fungal antibodies, and fungal culture of affected tissues might also be recommended.
In addition, cytology of fluid from the lungs (obtained by tracheal wash under anesthesia) can be diagnostic for the fungus. Fungal infections can take a long time to treat. It’s important to diagnose these types of infections as soon as possible so proper treatment may be started.
Often, dogs can fight off the infection themselves and may not need treatment. However, if a chronic cough or infected tissues are noted during your dog’s exam, 6-12 months of anti-fungal medication may be necessary to rid your dog of this infection.
Valley Fever (Coccidioidomycosis) in Dogs and Cats
Fungal Infections: Coccidioidomycosis
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