Blastomycosis
Definition
Blastomycosis is a systemic fungal infection that usually originates in the lungs and then disseminates to order organ systems.
Etiology
Blastomycosis is caused by dimorphic fungus Blastomyces dermatitidis. Infection usually occurs by inhalation of infection conidiophores from environment. Water plays important role in the spread of the disease.
Patophysiology
·A small spore (conidia) is shed from the mycelial phase of the organism growing in the soil and inhaled, entering the terminal airway
·At body temperature, the spore becomes yeast, which initiates the infection in the lungs.
·From this focus of mycotic pneumonia, the yeast disseminates hematogenously throughout the body.
·Hematogeneous and lympatic dissemination leads too pyogranulomatous disease
·The eyes are commonlyaffected in both dogs and cats.
Species
Dogs: large breed dogs weighing ≤ 25 kg, especially sporting breeds, may reflect exposure rather than susceptibility. Most common 2–4 years of age, uncommon after 7 years of age and disease predominant in male’s dogs.
Clinical presentation/signs
Ocular sign include conjungtivitis, corneal oedema, corneal vascularization, anisacoria, secondary glaucoma,anterior uveitis, granulomatous skin lesions, exopthalmos, optic neuritis.
Diagnosis
Diagnosis is based on the identification of the characteristic yeast within lesions, espectially within infected lymph nodes, skin and eyes. Serologic test are availablein endemic areas.
Differential Diagnosis
·Respiratory signs: bacterial pneumonia, neoplasia, heart failure, or other fungal infection
·Lymph node enlargement, similar to lymphosarcoma
·The combination of respiratory disease with eye, bone, and skin involvement in a young dog suggests the diagnosis.
Treatment
Itraconazole
·Dogs: 5 mg/kg PO q12h with a fat-rich meal, such as canned dog food, for the first 3 days to achieve a therapeutic blood concentration as soon as possible; then reduce to once a day
·Cats: 5 mg/kg PO q12h; open the 100-mg capsules containing pellets and mix with palatable food
·Treat for a minimum of 60 days or for 1 month after all signs of disease have disappeared.
Ketonazole and amphotericin B are effective in treating some cases of canine Blastomycosis.
Management/Prevention
Location of environmental growth of Blastomyces organisms unknown; thus difficult to avoid exposure, restricting exposure to lakes and streams could be done but is not very practical. Dogs that recover from the infection are probably immune to reinfection.
( source Blastomycosis)
Blastomycosis is a systemic fungal infection that usually originates in the lungs and then disseminates to order organ systems.
Etiology
Blastomycosis is caused by dimorphic fungus Blastomyces dermatitidis. Infection usually occurs by inhalation of infection conidiophores from environment. Water plays important role in the spread of the disease.
Patophysiology
·A small spore (conidia) is shed from the mycelial phase of the organism growing in the soil and inhaled, entering the terminal airway
·At body temperature, the spore becomes yeast, which initiates the infection in the lungs.
·From this focus of mycotic pneumonia, the yeast disseminates hematogenously throughout the body.
·Hematogeneous and lympatic dissemination leads too pyogranulomatous disease
·The eyes are commonlyaffected in both dogs and cats.
Species
Dogs: large breed dogs weighing ≤ 25 kg, especially sporting breeds, may reflect exposure rather than susceptibility. Most common 2–4 years of age, uncommon after 7 years of age and disease predominant in male’s dogs.
Clinical presentation/signs
Ocular sign include conjungtivitis, corneal oedema, corneal vascularization, anisacoria, secondary glaucoma,anterior uveitis, granulomatous skin lesions, exopthalmos, optic neuritis.
Diagnosis
Diagnosis is based on the identification of the characteristic yeast within lesions, espectially within infected lymph nodes, skin and eyes. Serologic test are availablein endemic areas.
Differential Diagnosis
·Respiratory signs: bacterial pneumonia, neoplasia, heart failure, or other fungal infection
·Lymph node enlargement, similar to lymphosarcoma
·The combination of respiratory disease with eye, bone, and skin involvement in a young dog suggests the diagnosis.
Treatment
Itraconazole
·Dogs: 5 mg/kg PO q12h with a fat-rich meal, such as canned dog food, for the first 3 days to achieve a therapeutic blood concentration as soon as possible; then reduce to once a day
·Cats: 5 mg/kg PO q12h; open the 100-mg capsules containing pellets and mix with palatable food
·Treat for a minimum of 60 days or for 1 month after all signs of disease have disappeared.
Ketonazole and amphotericin B are effective in treating some cases of canine Blastomycosis.
Management/Prevention
Location of environmental growth of Blastomyces organisms unknown; thus difficult to avoid exposure, restricting exposure to lakes and streams could be done but is not very practical. Dogs that recover from the infection are probably immune to reinfection.
( source Blastomycosis)
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