Dog Owner's Home Veterinary Handbook.pdf - Mr. Walnuts

SPOROTRICHOSIS
This is a skin and subcutaneous infection acquired by contact with spores in
the soil. The spores gain access through puncture wounds caused by thorns
and splinters; therefore, the disease is seen most often in hunting dogs. Most
cases are reported in the northern and central portions of the United States,
especially along coastal areas and river valleys.
A nodular, draining, crusted sore forms at the site of the skin wound, usually
on the trunk or head. There may be several small firm nodules in the
lymph glands that form a chain beneath the skin. On rare occasion the disease
becomes systemic and spreads to the liver and lungs. The outlook for
these dogs is guarded.
The diagnosis is made by removing a piece of tissue and examining it under
the microscope; or more conclusively, by growing the fungus in culture. A fluorescent
antibody test can be performed on infected tissue or serum.
Treatment: Response is excellent when the infection is limited to the skin
and surrounding tissues. Potassium iodide (a saturated solution) has been
used, but care must be taken due to possible toxicity. Antifungals of the imidazole
group (as described for Histoplasmosis, page 81) are therefore the agents
of choice. Treatment needs to be continued for a month after clinical signs are
resolved.
Public health considerations: Sporotrichosis is known to infect humans
handling animals with infective drainage. It is important to wear rubber
gloves and take strict hygienic precautions when handling all animals with
draining wounds.
Protozoan Diseases
Protozoa are one-celled animals that are not visible to the naked eye, but are
easily seen under the microscope. They are usually carried in water. A fresh
stool specimen is required to identify the adult parasite or its cysts (called
oocysts).
NEOSPOROSIS
INFECTIOUS DISEASES • 83
Dogs and herbivores are hosts to Neosporum caninum, with cattle as the
intermediate host. Dogs initially acquire the infection by eating infected
meat, but once infected, a bitch can pass this on through the placenta to her
unborn puppies. The risk to humans is minimal.
Dogs will show nerve and muscle problems, possibly even leading to paralysis.
Pneumonia, heart problems, and skin problems may also be seen. Blood
tests and muscle biopsies are the main means of diagnosis.