The world of vaccinations is quickly changing. For years, puppies received a series of combined vaccinations beginning at four to six weeks and continuing every two to four weeks until the pup reached sixteen to twenty weeks of age. Boosters were recommended every year thereafter for the life of the dog.
The reason for the annual boosters was that the vaccinations had only undergone duration-of-immunity tests for a twelve-month period. In other words, a dog might still have 100 percent protection from a deadly virus twenty-four or even thirty-six months after the booster was given. But because testing had only been completed for a dog's immunity at twelve months, the vaccinations could not be approved by the United States Department of Agriculture (USDA) for longer periods.
Veterinarians were faced with a dilemma. Vaccination protocols were emerging from veterinary schools encouraging a three-year protocol (boosters every three years) but since there weren't duration-of-immunity tests for this time period (except for the rabies vaccination), veterinarians were faced with a liability issue. If they recommended vaccinations after the initial puppy series be given only every three years, in the unlikely case that a dog became ill with a disease, the veterinarian would be faced with a nasty law suit.
Some veterinarians offered to test their clients' dogs' blood to find out what their immunity levels were; however, this test was more expensive than the actual vaccines, so few dog owners took their veterinarians up on this offer.
When it comes to vaccines, the size of a dog doesn't matter. Whether your Chi pup is only twenty-four ounces, she will receive the same dosage of vaccine as a thirty-pound puppy. The reason for this is that the injection contains the minimum amount of vaccine necessary to stimulate a dog's immune system to create antibodies, and this is the same regardless of size.
Now, as of April 2005, veterinarians have been able to offer a combined canine vaccine for distemper, adenovirus, and parvovirus that carries a three-year duration-of-immunity approved by the USDA. With this vaccine, the puppy vaccine schedule also is modified: the puppy is now to receive only two injections — one at eight or nine weeks and the second at twelve weeks.
Adverse reactions to vaccines are not uncommon in Chihuahuas. An adverse reaction usually occurs within the first twenty-four hours after injection. These can range from heat and inflammation at the site of the injection to complete anaphylactic shock or falling ill from the disease for which the vaccine is meant to produce protection. Talk to your veterinarian to make sure you know exactly what to look for, and remember that an adverse reaction is an emergency!
Vaccinations are divided into what are called core vaccines — or those deemed absolutely necessary for the protection of your Chi's health — and non-core vaccinations, which are recommended only if the risk of falling ill from a disease is substantially higher than the risk of suffering an adverse reaction to the vaccine itself.
The core vaccinations, as recommended by the AVMA, are canine distemper, canine parvovirus, and adenovirus-hepatitis (usually packaged as a combined vaccine in one injection); as well as a vaccination for rabies.
Non-core is the name given to vaccinations that may or may not be necessary for a puppy or dog, depending on the individual dog's risk of coming in contact with a disease. Among the non-core vaccinations are those for bordatella, canine adenovirus-2 (CAV-2), and parainfluenza (the three most common causes of respiratory infection, also known as kennel cough), giardia, Lyme disease, and measles.
Coronavirus, formerly a core vaccine, is no longer considered a deadly threat to puppies. Research has found that the virus is self-limiting and does not cause very serious illness. Therefore, the risk of an adverse reaction to the vaccine far outweighs the risks of becoming ill with the disease.
Vaccinations for kennel cough are recommended for puppies and dogs that regularly come in contact with large numbers of dogs. If you plan on showing your Chihuahua or competing in performance events, your veterinarian will likely recommend vaccinations for these three diseases. Additionally, if you plan on traveling without your Chihuahua, she will need to be up to date on her bordatella vaccine in order to be accepted into any boarding kennel.
Giardia is also known as beaver fever. Unless your Chi will be regularly exposed to water sources that have the potential to contain this protozoan, your veterinarian is not likely to recommend this vaccine. Dogs become infected when they drink from streams, brooks, puddles, or other natural water sources that contain giardia in cyst form. The cysts are passed into water by an infected animal, often beavers.
Lyme disease is a concern mostly for those dog owners whose dogs hunt, work, or play in tick-infested areas that are known to carry Lyme disease. However, the disease is not limited to these areas; pet owners walking their dogs in suburban neighborhoods have been infected by ticks carrying this disease. Most likely, providing your Chihuahua with a daily once-over after walks to check for ticks and/or applying a tick repellent to your Chi will provide enough protection for your dog with less risk of side-effects than the Lyme disease vaccine itself.
And then there's measles. Surprisingly, the human measles virus shares some antigens with canine distemper virus. In areas where canine distemper is literally running rampant, your veterinarian may recommend vaccinating with the measles vaccine (along with the canine distemper vaccine) to provide your Chi with some crossprotection.