Dog owners look forward to this time of year, happily
transitioning from the cold, unfriendly Midwestern winter and the confines of
their home to the verdant fields of spring. But with the return of flowers and wildlife
come warm-weather diseases, and one is particularly pernicious: leptospirosis.
Leptospirosis (a.k.a. lepto) is a bacterial infection transmitted
by a wide variety of livestock and wildlife, including deer, opossums,
squirrels, skunks, coyotes, raccoons, and rodents. The bacteria from infected
animals are transmitted through urine (and other body fluids, except saliva)
into water and soil, where they can survive for months. The organisms enter the body through the
skin, eyes, nose, or mouth. Drinking,
swimming in, and even walking through contaminated water can cause
infection. Affected animals may excrete
the bacteria into the environment for months and sometimes even years.
Because water and moist soil are sources of lepto, there’s a
seasonality to the disease. Cases start
appearing in the spring, with the highest number seen from July through
November. The number of cases surges
during periods of heavy rainfall.
Burgeoning suburbs
have expanded into rural areas, forcing the wildlife to adapt to living among
us. But if you assume that only rural or
suburban dogs are at risk, think again. Besides
a bumper crop of rats and mice, large
populations of coyotes that have made cities like Chicago their
habitat. Happily, you don’t have to
worry about outdoor cats being infected; they seem to be unaffected by the
disease.
Symptoms of lepto begin to appear 5 to 15 days after
exposure and can be attributed to damage to the kidneys, liver, and vascular
system. Fever, lethargy, vomiting,
diarrhea, loss of appetite, and jaundice are commonly seen. The
severity of clinical signs depends on how virulent the organism is; I’ve seen
moderately sick dogs as well as dogs that are critically ill.
Blood tests can point us to lepto, but the diagnosis is only
tentative: Other diseases produce similar symptoms and lab results. There’s a more specific test, the PCR, but
the results can take 10 days — very frustrating! If we suspect that a patient has lepto, we’ll
begin treatment without waiting for the PCR results. That is wise because it’s possible (although
not very common) that the pet’s owners could contract the disease from their
dog’s infected urine.
Leptospirosis is treated using long-term antibiotics. Some cases can be so severe that supportive
care and hospitalization at a critical-care facility are needed to save the
patient’s life. Dogs not given adequate
treatment can die. Although many pets
fully recover, a few can develop chronic kidney or liver disease, neither of
which is curable.
A decade ago, the vaccines for lepto had serious adverse
effects and earned a bad reputation that persists today. But the new vaccines are much better, and, as
with other vaccines, serious reactions are very rare. The vaccine prevents the four main strains,
or “serovars,” of lepto. Occasionally a
vaccinated dog will contract the disease if he has the misfortune to be exposed
to a less common serovar.
“But wait!” you say. “My dog hardly goes outside and barely
steps on the grass! She doesn’t need
this vaccination.” I learned otherwise
from Max, a 6-pound Yorkshire terrier. I
discussed risk factors with his owner, and she decided that his danger of
exposure was quite low; the little guy hates getting his paws wet. Guess who got lepto? After a week at Veterinary Specialty Center
in Buffalo Grove and $8,000 in medical expenses, Max recovered. But I’ve never forgotten it, and with the
increasing incidence of lepto in Lake County, we’re recommending that all dogs
get the lepto vaccinations: two injections three to four weeks apart, and an
annual booster.
Yup, we know it’s yet another expense. But in this case, an ounce of prevention
really is worth a pound of cure ̶
especially if the “pound of cure” runs into thousands of dollars.
