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An
Overview of Leptospirosis
Leptospirosis
is a disease caused by spiral-shaped bacteria known as leptospires.
Infections occur worldwide and may infect humans in addition to a multitude
of domestic and wild animals. The highest incidences of leptospirosis
occur in warm, semitropical areas, but during warmer months nearly every
climate is affected. Fatalities are not overwhelmingly common, but there
is always the potential for a leptospirosis infection to become extremely
serious. Vaccines are widely available and, especially if your dog spends
time in slow-moving or stagnant water, highly recommended.
Why and how might my dog become infected?
Leptospirosis
may be transmitted from animal to animal in a number of different ways.
Direct contact, venereal or placental transfer, bite wounds, and ingestion
of infected meat have all been proven as methods of infection. Perhaps
the most common method however is via exposure to infected urine. Animals
suffering from leptospirosis shed bacteria in their urine in large quantities,
and thus anything that touches infected urine will be contaminated.
In this way vegetation, food, soil, water, and bedding may be infected.
Warm, stagnant or slow-moving water is a particularly welcoming habitat
for leptospires, and most infections probably occur when a dog (or human
or other animal) goes swimming in or drinks water harboring these bacteria.
The leptospires
enter the body through mucous
membranes or abraded skin. Once inside the bacteria enter
the bloodstream and multiply rapidly. The incubation
period between initial infection and manifestation of clinical
symptoms ranges between 2 and 26 days. After reproducing in the bloodstream
the bacteria invade their target organs, including the kidneys and liver.
How will my vet reach a diagnosis of leptospirosis?
A diagnosis
of leptospirosis is based upon a combination of clinical observations
and laboratory tests. Many subclinical infections will be asymptomatic
and therefore may never be diagnosed. Symptoms that do appear vary widely
in type and severity, and dogs with no apparent symptoms may in fact
be severely ill and die spontaneously. The majority of cases do however
exhibit some outward signs of infection, including loss of appetite,
fever of 39 to 40°C (103 to 104°F), severe muscle pain, stiffness
or reluctance to move, shivering, progressive weakness, and depression.
Dehydration often occurs as a result of vomiting and diarrhea.
Conjunctivitis
is often present accompanied by difficulty breathing and a dry, hacking
cough. If the disease is left untreated and allowed to progress, dogs
may have markedly cold extremities, gray-colored stools, and yellow
skin and eyes.
Beyond
examining physical condition, your veterinarian may perform laboratory
tests on urine and blood. These procedures can help detect abnormalities
in blood components, liver enzymes, electrolytes,
and urine chemistry. Serologic
tests can be carried out to detect the presence of antibodies specific
to leptospirosis.
The final
diagnosis will thus be the result of any and all laboratory tests combined
with clinical observations and the individual dog’s history of
exposure.
What are the treatment options for dogs with leptospirosis?
The goal
of treatment for leptospirosis is to control the bacterial infection
before serious and irreparable damage is done to the internal organs.
If the disease is caught at an early stage, antibiotics are the best
treatment option. Administration of any number of common antibiotics
will serve to shorten the duration of the disease, limit the amount
of time the dog will be a carrier of the bacteria, and decrease the
severity of liver and kidney damage.
More advanced
and serious cases of leptospirosis will require various forms of supportive
therapy in addition to antibiotics. The administration of lots of fluids
will help to compensate for abnormal liver and kidney function. Kidney
therapy may be undertaken with the goal of restoring proper urine production,
kidney filtration, and blood flow. Such measures are extremely important
to reverse kidney failure. Severe liver disease may necessitate blood
transfusions and other types of supportive therapy.
Treatment
procedures for leptospirosis are highly individualized and your veterinarian
will be able to provide you with information as to what is best for
your pet.
Can I vaccinate my pet against leptospirosis?
Vaccines
are complex substances and often raise many questions. For information
about vaccines in general, please goto An
Introduction to the World of Vaccines.
There
are a multitude of options available for vaccination against leptospirosis.
Any vaccination schedule should be discussed thoroughly with your veterinarian.
How else can I help prevent the disease?
All dogs
should avoid stagnant, muddy water as much as possible. Rodent problems
should be kept under control, as these animals often harbor leptospires
– not to mention a host of other pathogens.
Owners
should be aware if their dog is at an increased risk. Increased risk
activities include hunting, showing at large dog shows, swimming in
stagnant ponds, and living in areas with especially high incidences
of leptospirosis. All at risk animals should be properly vaccinated.
Any place
that has housed an infected animal must be thoroughly cleaned and disinfected
before another dog is introduced.
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