REGIONAL— It often starts as a seemingly innocuous cough or weepy eyes. Yet, if left untreated, the fungal disease blastomycosis can quickly sicken and eventually kill even the healthiest of …
REGIONAL— It often starts as a seemingly innocuous cough or weepy eyes. Yet, if left untreated, the fungal disease blastomycosis can quickly sicken and eventually kill even the healthiest of dogs. It even kills humans in Minnesota, including eight victims in 2018 alone.
While the Minnesota Department of Health (MDH) lists blastomycosis, often called “blasto” for short, as a rare occurrence, that’s not really the case here in the North Country, which Cook area veterinarian John Fisher refers to as a “kind of national headquarters for blasto.”
Fisher estimates he sees about 25 cases a year and notes that the Lake Vermilion area has been a chronic producer of blasto cases. “It’s a very high-risk area, which makes blasto a constant presence in our practice,” said Fisher.
It’s much the same at the Ely Veterinary Clinic, where longtime veterinarian Chip Hanson says he sees 30-40 cases a year. “Our clinic is the hottest clinic in the state [for blasto], and it might be the hottest in the country,” he said. Hanson agrees that the Lake Vermilion area appears to be the worst for generated cases of blasto, but he said it’s a common issue for dogs in places like Eagles Nest as well as Moose Lake, located east of Ely.
The number of reported cases of blasto has been rising steadily in recent years, although Hanson said that could well be due to more consistent reporting. There were 150 cases reported in dogs in 2018 and indications are that that number will increase once final figures are available for 2019. Those figures almost certainly understate the extent of the disease, particularly in northern St. Louis and Itasca counties, where blasto is a relatively common disease in dogs.
The disease isn’t known to be contagious. You won’t catch it from your dog or a neighbor’s dog, and dogs don’t spread it between themselves. Instead, the disease is spread through the inhalation of the spores of the fungi Blastomyces dermatitidis or Blastomyces gilchristii that can be found in soil, especially in moist and wooded areas. Spores are more likely to be airborne after soil containing the fungi is disturbed by excavation, construction, or wood clearing. Dogs catch it much more frequently than humans most likely because they spend more time with their noses in the soil than most humans.
Even when humans inhale the spores, it doesn’t always lead to illness, according to the MDH. However, some people, for reasons that aren’t entirely clear, do experience symptoms as the fungus begins to grow, starting in the lungs but soon spreading to other parts of the body. While blasto is most often curable, in both humans and dogs, early detection and treatment with anti-fungal medication is key to a cure. Once well-established in the body, blasto is frequently fatal, even with treatment. Out of 50 diagnosed cases of blasto in humans in Minnesota in 2018, eight died as a result of the disease. In some cases, doctors who aren’t familiar with blasto mistake the symptoms for bacterial pneumonia, which can delay the start of the anti-fungal medications necessary to eliminate the disease. Antibiotics, which are frequently prescribed for bacterial infections, do nothing to stop the spread of blasto.
The Minnesota Department of Health issued an advisory this past September which advised healthcare providers that blasto cases had been higher than expected in 2019 and to watch for the symptoms in their patients. The most common symptoms of blasto in humans include cough, fever, chills, weight loss, night sweats and chest, joint or back pain. The MDH bulletin advised doctors to “ask patients about travel and outdoor activities, particularly to northeastern Minnesota,” where the fungi that cause the disease are “highly endemic.”
In dogs, blasto infection often shows up initially as a cough which develops as the fungus starts to fill their lungs. That’s typically the first sign of blasto in dogs, but others begin to develop as well. Dog owners typically notice their pet seems more tired than usual and they’ll often lose their appetite, almost completely, which is when many dog owners recognize there’s a serious problem. Once more advanced, the dog may start coughing up blood or develop skin lesions and eye problems which can lead to blindness. While veterinarians have made progress in treating the disease in recent years and can usually save dogs that aren’t already too compromised by the disease, blasto still kills dogs in the North Country every year.
When diagnosed, a vet will typically prescribe an anti-fungal medication that can be both effective and very expensive. In most cases, the dog will need treatment for at least three-to-four months before being re-tested for the presence of the fungus. More typically, the treatment lasts six months and can go even longer. With pills that can easily cost ten dollars a day, a full six-month course of treatment can run well over $2,500 once you consider other vet-related expenses, such as office visits and testing.
There is no immunization or other practical measure for preventing the disease, other than trying to avoid exposure to damp soils. While many dogs in the area contract blasto, Hanson said very few, if any, will contract the disease a second time since dogs do seem to build up an immunity once infected and treated.
Perhaps surprisingly, many cases of blasto are diagnosed in the early-to-mid winter here in the North Country, even though the fungi that cause blasto are frozen in the soil and typically covered with deep snow. It appears most dogs are infected in the late summer or fall, which is an active growing period for many fungi, yet the disease typically requires a one-to-three-month incubation period before symptoms appear. So, if your dog develops an unusual cough, or has weepy or goopy eyes, even in January, a trip to the vet is definitely in order. You just might be saving your dog’s life.