Valley Fever Coccidiodes organisms live in desert soils and produce long filaments that contain infectious spores. When the soil is disturbed, for example by a dog digging, by construction, or during a windstorm, the spores become airborne and can be inhaled. It is thought that dogs are so frequently diagnosed with Valley Fever because they commonly disturb and sniff dirt in their normal, daily activities. Once inside the lungs the spores mature and reproduce within “ spherules ” —small structures in which many “ endospores ” develop. With time, the spherules rupture releasing the endo- spores that can then spread the infection within the lungs or the rest of the body. Symptoms of Valley Fever in Dogs Many dogs who are exposed to Coccidiodes immitis do not develop symptoms of illness. In these cases, the dog ’ s immune system is able to contain and destroy the organisms before they can reproduce and cause disease. But when a dog is exposed to a large number of
spores or has a weakened immune system, Valley Fever can take hold. Typical symptoms of an infection that is limited to the lungs include:
Coughing
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Lethargy
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Fever
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Poor appetite
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Weight loss Additional symptoms are seen when the infection spreads outside of the lungs. Lameness is not unusual since the joints and bones are commonly affected. Seizures may develop if the brain is involved. Other possible symptoms include back or neck pain, abscesses, skin wounds that don ’ t heal as expected, swollen lymph nodes, eye abnormalities, heart failure, and more. In Arizona, it appears that the highest risk of exposure
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to Coccidiodes immitis occurs during the drier months of June, July, October, and Novem- ber, but this may not be the case in other parts of the country. Symptoms of infection may occur weeks, months, or even years after the exposure has occurred. Treating Valley Fever in Dogs Dogs that have been diagnosed with Valley Fever will be given anti - fungal medications which inhibit the growth of Coccidiodes organisms and allows the dog ’ s immune system to control and hopefully eliminate the infection. Commonly used medications in- clude fluconazole, itraconazole, and ketoconazole. Other options are available for dogs with severe infections or those that don ’ t respond to traditional treatments. Veterinarians may al- so prescribe anti - inflammatory medications, pain relievers, nutritional support, fluid therapy, and other treatments based on the specifics of a dog ’ s case. Valley Fever requires long - term treatment. Dogs are typically given anti - fungal medications for at least six months to a year, but some may need extended or even life - long treatment to prevent relapses. Veterinarians determine the best time to discontinue anti - fungal medica- tions based on a dog ’ s response to treatment and follow - up testing, and then they will closely monitor for relapses.
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