Research on Canine Blastomycosis

Blastomycosis (Blasto) in the dog is a commonly misdiagnosed systemic fungal disease of dogs, humans and other mammals. It is a great pretender and opportunist that can be mistaken for cancer, viral infections, Lyme Disease, or other systemic fungal diseases such as Valley Fever. Many dogs die or are euthanized each year due to delay in treatment as the result of a missed or erroneous diagnosis. Involvement of the eye may cause loss of vision or necessitate the removal of the eye. Relapse is also a concern, more often reported in females.

Canine Blastomycosis is caused by Blastomyces dermatitidis. This parasitic fungus grows as a mold in moist soil or decaying vegetation and releases spores into the environment that can be inhaled by animals or humans. Young dogs that have access to the outdoors are prime candidates for blastomycosis infection, but infection has been documented in all canine breeds, cats, horses and ferrets. Normally, blastomycosis infection will begin in the lungs after spores are inhaled and transform into large thick-walled budding yeast, which can multiply and disseminate to other areas of the body. Dissemination into organs, lymph nodes, eyes, joints, skin, as well as the central nervous system, is a grave risk.

A diagnosis of Canine Blastomycosis must be made promptly in order to begin treatment with antifungal medications. Unless Blasto is suspected, valuable time is often wasted testing and treating for viral and bacterial infections while the fungus disseminates. Without quick recognition, accurate diagnosis, and access to reasonably priced medications, many animals are unnecessarily lost to Blasto.

Blastomycosis cannot be eradicated from the environment, however, one may attempt to avoid or remove possible sources of contamination, such as mulched areas of flowerbeds, paths, bedding, areas of wetlands, etc. The idea of a commercial fungicide has been discussed, but there are none currently available that are effective against Blasto. With the advent of compounding pharmacies and generic antifungal medications, treatment is now more effective and affordable, making successful outcome for these animals more attainable than ever.

Risk Factors: Endemic Areas, US - Mississippi, Missouri, Ohio River valleys, Eastern Seaboard, areas adjacent to the Great Lakes. States with highest endemnicity are Wisconsin, Minnesota, Missouri, Illinois, Michigan, Kentucky, West Virginia, Arkansas, Tennessee, North Carolina, South Carolina, Louisiana, and Mississippi.

Other endemic states include Indiana, Iowa, Ohio, Virginia, Georgia, and Alabama. However, cases do occur outside the endemic areas. Endemic Areas, Canada - Blasto is prevalent in Kenora, Ontario. Also found in Manitoba, Ontario (Kenora, Sault Ste. Marie, Chapleau), Quebec, New Brunswick, in particular areas around the Great Lakes and in a small area a small area in New York and Canada along the St. Lawrence River. Has also been increasingly reported along the Georgian Bay coastline (including Midland and Penetang), Dryden, and in Southern Ontario at the Rockwood Conservation area.

Environment: Research shows that exposure to wet or decaying organic material, recently disturbed soil, rotting vegetation, bird droppings, and landscaping projects is a strong indicator of disease possibility. Some research has shown a strong link to wood mulch and importation of non-local soil. Patient history will often reveal exposure to mulched areas and disturbed soil in parks, yards, walking paths, etc.

Breed/Age: young, large-breed dogs with the highest rates of infection are normally Coonhounds, Pointers, and Weimaraners. This is normally attributed to higher exposure to endemic areas due to use in hunting. Breed, size, and age, however, are not a reliable indicator of susceptibility, as all are at risk

Symptoms: After initial spore inhalation, incubation can range from days to weeks. The presentation of Blasto is often non-specific, and can imitate a range of other diseases. Symptoms include:

Lethargy
Persistent fever of 103 degrees or more
Anorexia
Vomiting
Persistent, usually non-productiive cough
Exercise intolerance
Respiratory symptoms, fungal pneumonia
Ocular infection, sudden blindness
Depression
CNS symptoms: twitches, stumbling gait, loss of coordination
Skin ulcerations, non-healing lesions
Lumps, nodes, swellings
Weight loss
Hair loss
Lameness, fungal arthritis
Hematuria
Diagnostic Testing: Diagnosis is based on clinical signs, a thorough patient history, and laboratory findings. Not all findings are specific, some tests are faster and more efficient, and some cases may benefit from antifungal treatment even before definitive diagnosis.

Cytology: New Methylene Blue stain used to identify organisms from exudates of skin abcesses/lesions/sputum/fluid aspirated from lungs appears to be the fastest, most reliable and cost-effective method. Not all cases, however, will present with accessible material, necessitating further diagnostics. MiraVista Diagnostics Antigen Assay: Very high sensitivity with urine (studies show 92.9% sensitivity, specificity 79.3%), slightly less sensitive with serum. 4-5 days for results, at a cost of approx. $100. Also useful in monitoring the efficacy of antifungal therapy. Chest X-Ray and signature snowstorm pattern. Area Bone Radiograph Lymph node biopsy / fine needle aspiration. Serum Antibody Titer: regarded as a fairly poor diagnostic tool for Blastomycosis. Tracheal wash. Ultrasound

Be Aggressive:
Excerpt: Journal of Clinical Microbiology, October 2004, p. 4873-4875, Vol.
42, No. 10. Most patients with blastomycosis exhibit progressive illnesses that
require antifungal therapy. In one study, diagnosis was delayed for more than 1
month in nearly half of the cases. Blastomycosis was correctly suspected in only
20% of patients, resulting in unnecessary surgeries and treatment delays. In
two-thirds of patients who died of acute respiratory distress syndrome caused by
blastomycosis, the diagnosis was either not suspected or considered only after
the patient became moribund.
Treatment Options*:
Itraconazole (Sporanox) capsules: First line preferred treatment, given with a fatty food to increase bioavailability
Amphoterericin-B: Higher efficacy in patients with CNS involvement
Itraconazole (Sporanox) suspension: Shorter shelf-life, but can be given without food
Ketoconazole (Nizoral): In initial treatment w/Ampho-B, similar results as
Itraconazole - slightly less expensive
Fluconazole (Diflucan): Somewhat less effective than Itraconazole
Posaconazole: Higher cost, similar effects to Itraconazole, few studies
Voriconazole: Higher cost, somewhat better efficacy in cases w/CNS involvement, few studies
Prednisone: For treatment of inflammatory issues
In the past, Amphotericin-B was the only known medication useful against Blastomycosis and the other systemic fungal organisms. It was given intravenously and with care to keep the dose from harming the kidneys.

More recently, research has provided oral azoles that are highly effective in treating fungal infections. Itraconazole (Sporanox), Ketoconazole (Nizoral), and Fluconazole (Diflucan) are available as capsules and oral suspensions that may be administered for 3 to 6 months (depending on the severity of infection, treatment may be even longer).

Compounding pharmacies have made these medications much more affordable and available in custom dosages for different sized animals. Generic and brand name medications are equally effective, and given the very high cost of brand names, the generic compounded alternatives are saving lives that may have previously been lost due to the cost and length of treatment.

Treatment: Once Blasto is diagnosed or is highly suspected, treatment can be started with the appropriate antifungal medication. In the early stages of treatment large numbers of fungi begin to die in the lungs and often elicit an inflammatory response. Prednisone is sometimes prescribed to help reduce inflammation issues. Many of these animals are fighting a fungal pneumonia. As a result, respiratory distress is often a significant problem in the first few days following initiation of therapy. Since the severity of the infection will determine the amount of fungi inhabiting the dog’s lungs, early diagnosis and treatment is an efficient means of reducing post-treatment respiratory distress and can significantly influence a dog’s chances of survival.

The animal’s prognosis will always be guarded, and antifungal treatment is never a guarantee of recovery. Intense supportive care and a high level of commitment to recovery on the part of the owner are imperative. Round the clock care is often necessary. Removal to a medical facility for IV treatment and hydration may be helpful and sometimes unavoidable, but can be very stressful for a compromised animal. If the owners are able to provide care, the security of home and loved ones may reduce stress. The outcome will also vary with the degree of infection, whether Blasto has disseminated into other organs, CNS, bones, or in the event of secondary bacterial or viral infection.

Eye involvement may result in blindness or necessitate removal of eye(s). Recently some experimental treatments have reported some success in the nominal recovery of vision. These treatments can be fairly expensive, and are not a guarantee of sight recovery. (**See Dogs In Canada, by Rick Hayworth.)

During the first few weeks of therapy, the animal may become alarmingly ill, anorexic, and may have to be force-fed. Weight loss may continue; hydration and calories are important. During this time, the idea of eating healthy may need to be suspended in favor of getting any nutrition possible into the animal. Owners who have successfully treated their animals recommend the following:

Ensure Plus: added protein with about 300 calories per can; well tolerated, may be bottle-fed
Hill’s A/D canine "prescription" dog food: can be mixed with water and given by syringe
Canned Tripe
Sav-A-Calf Electrolytes Plus: very good reported results, may be bottle-fed
Canned Dog Food
Cooked chicken, chicken broth
Meal Bones-Whole meals
Stewed meats, soups
Burger
Peanut butter: lots of fat and calories, and they pretty much cannot avoid swallowing it
Frozen Gatorade
Frozen Ensure
Frozen Pedialyte: also helpful when used in a squirt or spray bottle
Cheese
Ice Cream
Margarine
Sausage
Eggs
Yogurt
Medication: Sources and Cost: Antifungal prescriptions from retail pharmacies can range from $4 to $9 per dose. As treatment must be continued for as long as 12 months, cost will be an issue that affects the owners’ decision regarding treatment vs. euthanasia. Compounding pharmacies have made generic and custom doses much more affordable. For example, the cost of generic Itraconazole 150 mg. from Pet Health Pharmacy in Arizona is approximately $1 per dose. Overnight shipping is available at a cost of about $8-$10 extra. These medications appear to be equally effective as brand name varieties and make the option of treatment more feasible for the owner.

Dog Health--Prostate Cancer

All intact (not neutered or not castrated) male dogs are more prone to prostate problems as a result of the effects of testosterone (male hormone) on this gland over time. The testosterone most commonly leads to benign prostatic hypertrophy (BPH) in older male dogs.

Symptoms
This condition results in an enlargement of the gland that as the name suggests (benign), is not a truly cancerous condition. The enlarged gland however, tends to be more prone to infections (prostatitis) because the blood flow through the enlarged gland tissue area is less efficient, and if bacteria lodge here, the infection can be difficult to control and clear.

The gland of an intact male dog is known to be more susceptible to cancer. This has been confirmed in scientific studies, and because of the delicate location of this gland around the junction of the bladder and the urethra (the tube leading to the outside via the penis), the cancers can be difficult to control or cure in this location.

You are obviously a responsible pet owner, and have been careful about preventing unwanted litters by keeping your male away from females. Unless you have firm plans to use this animal in a formal breeding program, the best prevention strategy for prostate problems is the surgery (castration).

Treatments
Many owners express concerns about surgery and anesthesia for their pets; this is a natural response. Dog lovers want to do the best for their "best friend", and need reassurance about surgery and the attendant risks. Your veterinary team can go over the steps involved, and many facilities will let you tour their establishment so that you can become familiar with the advanced medicine and surgery suites that they offer, and the focused care that they provide.

There is no such thing as zero risk for any procedure, anesthetic, medication, or other intervention, but with modern medicine, we are proud of, and have a great deal of confidence in our current level of practice. Most practices use the same anesthetic agents, equipment, and many of the monitoring systems that your own physician would use in a human hospital. Veterinary technicians (nurses) that assist the veterinarian during the procedure and anesthetic are highly trained paraprofessionals (look for AHT, RVT etc. on their name tag for proof of their certification).

The surgery itself is not a long one. The average procedure would take 10-20 minutes, and complications are rare. With proper post-operative rest and care, the chance of a problem is very low indeed. Most practices will see the dog back for a "post-op" check in 7-10 days, and during that early healing phase, they are especially willing and able to address any questions or concerns that might arise.

The risk of a routine surgery is very low, and it would not be considered an endangerment to health to make this decision on a dog's behalf. It is often helpful to review information, and discuss the decision further with the health care team before making the final decision. The potential devastation from possible future prostate problems would be generally viewed as a much more worrisome scenario than a sterile surgical procedure performed in a modern veterinary practice by an experienced veterinary surgeon and their support team.

Dog Cancer

Dog cancer, like human cancer, refers to any type of malignant tumor or growth (neoplasia) that invades the surrounding tissues, spreads to other parts of the body via the bloodstream, is likely to recur after attempted removal, and can cause death unless it is adequately treated or removed. While cancer can occur at any age, the chances of getting cancer increases with age, and because pets are living longer, the incidence of cancer has been increasing accordingly.

Symptoms
There are many signs that can be associated with cancer. Abnormal swellings that persist or continue to grow, sores that do not heal, bleeding or discharge from any body opening, difficulty eating or swallowing, a persistent lameness, difficulty breathing, urinating, or defecating, or persistent coughing are examples of specific signs which may arise. Weight loss, fevers, decreased appetite, and loss of stamina, though vague and non-specific, may also be suggestive of cancer.
There are literally as many types of cancers as there are types of cells. It is not known why normal cells become cancerous and begin to divide and multiply out of control. Environmental factors, genetics, toxins, and other biological factors are all possible contributors.

Treatments
Despite the poor prognosis that one normally associates with cancer, effective treat- ments are available for many types of cancer. Once a tumor has been detected, the eventual outcome can often be favorable if early detection is followed by timely intervention. A biopsy can usually determine what kind of cancer is involved and thus helping set the appropriate course of therapy.

Surgery is the treatment of choice with some cancers. A localized tumor can usually be effectively excised surgically and, when detected early, the procedure carries an excellent success rate. An attempt is made to determine if there has been any spread (or metastasis) to adjoining organs or tissues. Staging the disease helps to set the prognosis. If the growth turns out to be malignant, the veterinarian will suggest an appropriate course of action and will help you understand what might be expected in the future. In cases where a tumor proves to be inoperable and surgery is not curative, radiation, biological, or chemical therapies may be a viable alternative. During radiation therapy, the malignant cells are exposed to high levels of radiation to kill them. Similarly, chemotherapy utilizes medication to kill cancer cells while sparing normal healthy cells that are not dividing quickly. Sometimes a combination of therapies is prescribed such as surgery plus radiation. This is often the case when aggressive tumors are identified and this strategy helps to increase remission rates while reducing side effects.

Modern cancer management is much more than just the application of the above therapies. Nursing care advances such as nutritional support, pain management, grooming, soft bedding for comfort and ulcer prevention, physical therapy, and other supportive techniques have all contributed to improved expected outcomes, and the improved quality of life for a pet with cancer.

Treatment options should be discussed with your veterinarian and the average expected success rate of each option will be explained. In some cases, your veterinarian may refer your pet to an internist or a cancer specialist (oncologist) for further treatment. You are an important part of the care team when dealing with cancer, so make sure you understand what you can do to help the health care team at your practice optimize your pet's treatment.