Blastomycosis (Blasto) is a systemic, fungal infection caused by the soil organism Blastomyces dermatitidis. The organism grows in the soil and can be inhaled by dogs digging or sniffing in the soil. The organism travels to the lungs where it causes pneumonia and then can be disseminated in the bloodstream throughout the body. The Blasto organism causes a severe immune response which can result in dysfunction of the body organs affected.
Eighty-five percent of affected dogs have lung disease. Eyes, skin, lymphatic system, and bones are commonly affected also.
The incidence of Blastomycosis depends on environmental and wet soil conditions that favor growth of Blastomyces. Blasto is found most common along the Mississippi, Ohio, and Tennessee river basins which includes our area in central Illinois. Wet environments foster growth of the fungus; banks of rivers, streams, and lakes or in swamps; most affected dogs live within 400 meters of water. Exposure to recently excavated areas can increase the risk.
Large breed dogs weighing more than 50 pounds, especially sporting breeds are most commonly affected due to their increased exposure of digging and sniffing the soil. Young dogs, two to four years of age, are most commonly affected. It is very uncommon in dogs seven years and older.
Most common clinical signs of Blasto are: weight loss, depressed appetite, cough and difficult breathing, eye inflammation and discharge, lameness, and draining skin lesions. Dogs can exhibit a fever up to 104 degrees F, harsh dry cough, generalized or localized swelling of the lymph nodes, inflammation of uvea and conjunctiva and may lead to glaucoma. Dogs can be very painful and lame when the organism infects the bone. Blasto can also cause swelling of the testicles and prostate as well as inflammation of the heart.
The disease is most commonly diagnosed by radiographs showing a “snow storm” appearance within the lungs. Also in the last couple of years, a very accurate urine test helps to identify the disease and its severity.
Obviously, the earlier the disease is diagnosed and treatment started the better prognosis. Itraconazole is the drug of choice for treatment. Affected dogs should be treated for a minimum of 60 days or for one month after all signs of disease have disappeared. After 60 days, the patient should be re-xrayed and repeat urine test to determine the stage of disease.
Unfortunately, about 25% of affected dogs will die during the first week of treatment; early diagnosis improves chance of survival. About 20% of dogs will have a recurrence, usually within three to six months after completion of treatment and will need to be treated again.
Blasto is not spread from animals to people, except through bite wounds. Affected pet owners need to be aware that Blasto is acquired from an environmental source and that they may have been exposed at the same time as the patient; common source exposure has been documented in duck and raccoon hunters; the incidence in dogs is ten times that in humans. Owners of infected dogs that have respiratory and skin lesions themselves, should inform their physicians that they may have been exposed to Blastomycosis.
At our Dwight Veterinary Clinic, we see an average of five to 10 dogs per year with Blasto. The wetter the year, the more common the incidence of disease. So if your dog has a respiratory or skin infection that does not improve with the first round of antibiotics, be certain to discuss with your veterinarian the possibility of Blastomycosis.
Eighty-five percent of affected dogs have lung disease. Eyes, skin, lymphatic system, and bones are commonly affected also.
The incidence of Blastomycosis depends on environmental and wet soil conditions that favor growth of Blastomyces. Blasto is found most common along the Mississippi, Ohio, and Tennessee river basins which includes our area in central Illinois. Wet environments foster growth of the fungus; banks of rivers, streams, and lakes or in swamps; most affected dogs live within 400 meters of water. Exposure to recently excavated areas can increase the risk.
Large breed dogs weighing more than 50 pounds, especially sporting breeds are most commonly affected due to their increased exposure of digging and sniffing the soil. Young dogs, two to four years of age, are most commonly affected. It is very uncommon in dogs seven years and older.
Most common clinical signs of Blasto are: weight loss, depressed appetite, cough and difficult breathing, eye inflammation and discharge, lameness, and draining skin lesions. Dogs can exhibit a fever up to 104 degrees F, harsh dry cough, generalized or localized swelling of the lymph nodes, inflammation of uvea and conjunctiva and may lead to glaucoma. Dogs can be very painful and lame when the organism infects the bone. Blasto can also cause swelling of the testicles and prostate as well as inflammation of the heart.
The disease is most commonly diagnosed by radiographs showing a “snow storm” appearance within the lungs. Also in the last couple of years, a very accurate urine test helps to identify the disease and its severity.
Obviously, the earlier the disease is diagnosed and treatment started the better prognosis. Itraconazole is the drug of choice for treatment. Affected dogs should be treated for a minimum of 60 days or for one month after all signs of disease have disappeared. After 60 days, the patient should be re-xrayed and repeat urine test to determine the stage of disease.
Unfortunately, about 25% of affected dogs will die during the first week of treatment; early diagnosis improves chance of survival. About 20% of dogs will have a recurrence, usually within three to six months after completion of treatment and will need to be treated again.
Blasto is not spread from animals to people, except through bite wounds. Affected pet owners need to be aware that Blasto is acquired from an environmental source and that they may have been exposed at the same time as the patient; common source exposure has been documented in duck and raccoon hunters; the incidence in dogs is ten times that in humans. Owners of infected dogs that have respiratory and skin lesions themselves, should inform their physicians that they may have been exposed to Blastomycosis.
At our Dwight Veterinary Clinic, we see an average of five to 10 dogs per year with Blasto. The wetter the year, the more common the incidence of disease. So if your dog has a respiratory or skin infection that does not improve with the first round of antibiotics, be certain to discuss with your veterinarian the possibility of Blastomycosis.
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