LEPTOSPIROSIS
A Modern-Day Threat
by Beverley Cross
It’s time to start using the 8-way vaccinations on your litters again, and if your adult
hounds haven’t had a Lepto shot in a while, give them one, or have your veterinarian
give them one, too. Leptospirosis has reared it’s ugly head pretty much all over the
country (it used to be more prevalent in the northeast and south in marshy areas.) This is
a nasty disease which left untreated or undiagnosed, could mean the difference between
life or death in your dogs. It’s important that you not only vaccinate for it, but keep
alert for the signs and symptoms.
Leptospirosis is a bacterial disease caused by
pathogenic members of the Genus
Leptospira. This disease occurs worldwide in
many animals, including our dogs. The canine
disease presents as an acute infection of the
kidney and liver and sometimes as a
septicemia, (or better known as blood
poisoning). Because many aspects of the
infection are poorly understood, there is the
possibility that the disease in dogs may go
undiagnosed.

While diagnostic methods have improved
over the years, most are relatively insensitive.
This re-emerging infection is most likely
influenced by the cycles of infection in
wildlife, where the infection may be
transmitted to domestic animals. Chronic
kidney disease commonly follows infection,
and abortions may occur in pregnant dams.
Due to recent trends and events in the
Northeastern states, leptospirosis has
become suspect of differential diagnoses for
dogs that are seen for acute liver and/or
kidney disease. Other factors that may affect
the pattern of disease in dogs are the
vaccination history and the use of antibiotics.
Common clinical signs reported in dogs
include fever, vomiting, abdominal pain,
diarrhea, refusal to eat, severe weakness and
depression, stiffness, severe muscle pain, or
inability to carry puppies to term. Generally
younger animals are more seriously affected
than older animals.

Leptospira do not multiply outside of the host
and their survival depends on environmental
conditions in which leptospirae are found,
e.g., soil and water conditions. Leptospira
organisms can survive up to 180 days in wet
soil, for many months in surface water and
survive better in stagnant rather than
free-flowing water. The source of infection to
animals is either by direct contact with
infected urine, fetal and placental material or
fluids, uterine discharges, or indirect contact
from a contaminated environment.

A higher incidence of disease is more likely in
soils with an alkaline pH, during the wet
season (high rainfall areas), in low lying areas
susceptible to run off conditions during rains,
warm and humid climates, areas with an
abundance of surface water resulting in
marshy fields and muddy areas. Although
dogs in fenced yards may be exposed to
urine from wildlife, (including rodents) dogs
such as hunting and show breeds, and all
those with access to ponds or slow-moving
streams are at greater risk than housedogs.
Once leptospires penetrates the mucus
membranes or intact or abraded skin,
organisms rapidly invade the bloodstream over
the next 4 to 11 days, creating a leptospiremia.
In susceptible dogs, leptospires usually establish
a septicemia and spread systemically to the
internal organs, including the liver and kidneys,
or to the placenta and fetus of the pregnant
dam. If a dog had been vaccinated, it still may
have antibodies, or it may mount an anamnestic
(or recalled) response in the absence of
antibodies. Young dogs who are unvaccinated,
or whose dams were not vaccinated, are
obviously at greater risk of severe disease and
death that may occur due to an acute
septicemia or hemolytic anemia (destruction of
red blood cells). Previously vaccinated older
dogs who, later, become infected naturally with
a field strain similar to the vaccine given at an
early age generally have minimal clinical signs.

The treatment goals for acute cases of canine
leptospirosis are to control the infection in the
liver and kidneys before irreparable damage is
done, and to suppress the leptospiruria.
Severely ill, acute cases require a high degree of
supportive care for survival and the immediate
administration of fluids is essential. The
prognosis is guarded for patients with acute
renal failure and/or liver disease. Vaccination is
especially recommended in endemic areas.
Dogs usually recover after 2 weeks, if treated
promptly with antibiotics and intravenous fluids,
however, if kidney or liver involvement is
severe, the infection may be fatal.

Owners should be advised that leptospirosis is
a zoonotic disease that can be spread to
humans and is spread mainly by the urine of
infected dogs. An infected dog’s housing
and outside areas need to be thoroughly
disinfected. Optimum prevention of contact
would be vaccination, avoiding muddy, stagnant
water (not always practical for the hunting
beagle) and rodents. Needless to say, rodent
control is a must and it is not wise to allow dogs
to eat dead animals of any kind in the field.  
Always consult your veterinarian if your dog
presents any of the symptoms mentioned in this
article.