The Lepto vaccine has been call the killer vaccine because it is the #1 cause of serious reactions in small dogs.
The Lepto vaccine for dogs should be avoided at all costs, because it can be deadly for your little dog. Small dogs like Morkies should have fewer shots, less often and more spread out, according to experts in the animal care business, including the venerable AAHA (American Animal Hospital Association).
The AAHA is the only organization that accredits veterinary practices in the United States and Canada, and sets the standard for quality animal care. This group warns that too many vaccinations at the same time, especially those that are recognized as dangerous like the Lepto vaccine for dogs, can make your dog very sick, feverish, nauseated and eventually dehydrated. DEATH can follow!
The AAHA specifically advises that the Leptospirosis vaccination is “not recommended” for any dogs.
The ASPCA also recommends against this vaccination, even for shelter dogs, often at more risk. Read their page on the Lepto vaccine for dogs here.
The Lepto vaccine for dogs is not a core vaccine. This means it’s not recommended for all dogs in all communities.
The Lepto vaccine is the “L” is combo shots and it’s highly recommended that you skip it for your small dog.
What is Lepto or Leptospirosis?

Lepto certainly can make your morkie sick, but it’s not a SERIOUS illness.
Sometimes called Swamp Fever or Rat Catcher’s Yellow, Lepto symptoms include fever, muscle pain, vomiting and diarrhea, poor appetite, lethargy, depression, and sometimes blood in the urine.
In more serious cases, the dog may be jaundiced – Lepto can attack the liver and kidneys. (This is hard to see in a dog – but look for a yellowing of his gums.)
So why not get this vaccination?
The disease doesn’t sound very pleasant but there are a couple of things to remember in assessing it for your Morkie…. First, there are over 100 strains of Leptospirosis and the vaccine protects against only 4.
Second, dogs who run free in rural environments – such as hunting dogs – drinking deep from local streams and ponds, are most likely to catch the disease. Does your Morkie go on long hikes, camp deep in the woods or have wilderness adventures? Hmmmm, probably not.
Third, even if your Morkie were to contract this disease, it’s usually successfully treated at home. Extreme cases might require a stay in the vet’s office for dehydration and more meds to be cured.
Symptoms of Lepto infection
Symptoms of a Lepto infection include fever, muscle pain, vomiting and diarrhea, poor appetite, lethargy, depression, and blood in the urine. In more serious cases, the dog may be jaundiced – Lepto attacks the liver and kidneys. And – this is hard to see in a dog – but look for a yellowing of his gums.
Medical treatment will definitely help a dog with Lepto – milder cases can be treated at home with help from your Vet; very serious cases require hospitalization where your dog will get antibiotics and other medications to control vomiting and diarrhea.

Adverse reactions to the Lepto vaccine for dogs
Leptospirosis is a “killed” vaccine. It’s also been called the “killer” vaccine because it is the #1 cause of adverse reactions in small dogs. They can have a severe allergic reaction to the Lepto vaccine, particularly younger dogs and small breed puppies.
In fact, this vaccine has a reputation for being the most likely
to cause reactions, also known as anaphylactic shock reactions (“anaphylactic” = allergic). These include:
- vomiting
- severe diarrhea
- panting and wheezing
- disorientation, dizziness
- collapse
A killed vaccine has been inactivated It’s made with the version of the germ that causes a disease buy inactivated vaccines usually don’t provide immunity (protection) that’s as strong as live vaccines. So you may need several doses over time (booster shots) in order to get ongoing immunity against diseases.
Read more about dog vaccinations here

If you’re alarmed by the thought of your dog catching lepto, and wondering whether you should give your dog the leptospirosis vaccine, you may first want to read some facts about the disease and the vaccine.

A final note about Lepto
Today, the tests for actual Leptospirosis infection are much more accurate than ever and incidents of the illness are reported more frequently and accurately — compared to other illness which is registered probably between 1 and 10% of the time.
That and the new interest in this disease can make you think it’s an epidemic. It’s NOT.
FOR MORE INFORMATION, check out this excellent article by Dana Scott.
