Vaccines are the hot topic of 2020 (among other things), so what actually are they? How did we discover vaccines? Why do we use them? And how do they work? Read on and discover the truth about vaccines….

According to the CDC the definition of a vaccine is “something that stimulates your immune system to produce antibodies, exactly like it would if you were exposed to the disease. After getting vaccinated you develop immunity to that disease, without having to get the disease first”. This is what makes vaccines powerful medicine. Unlike most medicines, which treat or cure disease that you already have, vaccines PREVENT them.

The CDC also states “Vaccines contain the same germs that cause disease, but they have either been killed or weakened to the point that they don’t make you sick. Some vaccines contain only a part of the disease germ.”

Where did the concept of vaccines come from? Vaccines date back hundreds of years. Buddhist monks drank snake venom in order to gain immunity from snake bites. In 17th Century China, Cowpox goo was smeared into skin wounds to confer immunity. In 1796 Edward Jenner (considered to be the founder of Vaccinology in the western world) inoculated a 13 year old boy with Vaccinia Virus (Cowpox) and was able to demonstrate immunity to the similar disease, Smallpox, and hence the first Smallpox vaccine was developed in 1798. It was further developed over the 18th and 19th centuries by mass immunization, and Smallpox was finally eradicated from the world in 1979….. quite an achievement.

Louis Pasteur continued to develop vaccines (for Cholera and Anthrax), and a vaccine for the Plague was invented in the late 19th Century.

Between 1890 and 1950 vaccine development continued to progress and the Bacillus-Calmette-Guerin (BCG) vaccine was invented, which is still in use today for Tuberculosis.

Other vaccines developed include:

Tetanus (Alexander Glenny, 1923)
Diptheria (1926)
Pertussis (Whooping Cough, 1948)
Polio (1950-1985. Mass Polio vaccination has now eradicated the disease from many regions of the world. A famous Polio sufferer was Franklin D. Roosevelt who was 39 when he contracted the disease)
Measles (the next target for elimination via vaccination)
Mumps
Rubella
Hepatitis
Influenza

What different types of vaccines are there? There are 4 main types of vaccinations:

LIVE ATTENUATED VACCINES. These vaccines use a live but weakened form of the disease. They are similar to the natural infection they prevent and create a strong and long-lasting immune response. Examples include: MMR (Measles, Mumps, Rubella), Smallpox, Chickenpox.
INACTIVATED VACCINES. These vaccines use the killed version of the germ that causes the disease. Inactivated vaccines don’t provide immunity that is as strong as a live-attenuated vaccine, so you often need several doses (boosters) over time. Examples include: Hepatitis A, Influenza, Polio, Rabies.
RECOMBINANT VACCINES. These vaccines only use specific pieces of the germ - like a protein, sugar or part of the capsule (casing) surrounding the germ. They give a strong immune response and are safer in people who may be compromised or have long term health issues. Examples include: Hepatitis B, Whooping Cough (Pertussis), Shingles.
TOXOID VACCINES. These vaccines use a toxin made by the germ that causes a disease. They create immunity to the parts of the germ that cause a disease instead of the germ itself. You often need booster shots with this type of vaccine to get ongoing protection. Examples include: Diptheria, Tetanus.

There are also 2 new types of vaccines in the works in this miracle age of medicine…. DNA VACCINES (easy and inexpensive to make, producing strong, long-term immunity) and RECOMBINANT VECTOR VACCINES (these vaccines act like a natural infection so they can teach the immune system how to fight).

VACCINES AND OUR PETS.

So how do we utilize vaccines in pets, what diseases do we want to prevent, and which of our furry friends should be vaccinated? Let’s start with dogs…..

The vaccines available for use in dogs are: Rabies, Canine DHPP/DAPP (“Distemper”), Lyme Disease, Leptospirosis and Bordetella (“Kennel Cough”).

RABIES…. Everyone has heard of this one. Rabies is an acute viral infection that can affect all mammals. This includes our own pets (dogs, cats, ferrets etc) and of course humans. It is contracted from a bite of an infected animal, transmission is due to the virus being present in the infected animals saliva. Younger animals are more susceptible and it is ALWAYS fatal.

Once Rabies enters the body it travels along the nerves to the brain (which can take days, weeks or even months) to then present as a clinical disease. Clinical signs include:

Anxiety
Aggression
Restlessness
Erratic Behavior
Weakness
Poor Coordination
Tremors

Rabies vaccination is essential, usually mandated by State Law (true of NJ and PA), and is necessary to protect our pets from Rabies. Even indoor pets must receive a Rabies vaccine by law. In rare cases pets may be exempted from a Rabies vaccine by a veterinarian due to severe/life-threatening conditions.

Rabies kills an estimated 59,000 people (yes, that figure is correct!) annually and globally. 1 person in the USA is treated for potential Rabies exposure every 10 minutes!

In the early 1900’s in the USA, there were 6,000 cases of Rabies in domestic animals - this number does not include wild animal cases. By 2017, vaccination for Rabies in our fur kids reduced this number to less than 400.

Rabies in the USA is mostly transmitted by wildlife, and with 5,000 cases in wild animals last year the threat is real, for pets and their people. Vaccinating your pet for Rabies will protect you too.

THE CANINE “DISTEMPER” VACCINE…. DHPP or DAPP = Distemper, Hepatitis/Adenovirus, Parainfulenza, Parvovirus. Let’s take one at a time.

DISTEMPER. What is canine Distemper? This disease is caused by a virus and affects the respiratory, gastrointestinal and nervous systems of dogs. It is a contagious disease and is very serious. The virus can also be found in wildlife such as foxes, raccoons, coyotes and skunks, as well as minks and ferrets - all of which can be found in New Jersey and Pennsylvania, and specifically Hunterdon County.

Dogs are usually infected via airborne exposure (coughs, sneezes, and ocular (eye)/nasal secretions) from an infected animal, but it can also be spread via fomites, for example shared bowls and equipment. Infected dogs shed the virus for months and mother dogs can pass the the virus via the placenta to their puppies.

Symptoms:

Pus-like ocular discharge
Fever
Nasal Discharge
Coughing
Lethargy
Decreased Appetite
Vomiting

Once the virus starts to attack the nervous system, other symptoms are seen:

Circling Behavior
Head Tilt
Muscle Twitches
Convulsions with Jaw Chewing Movements
Salivation
Seizures
Complete or Partial Paralysis

The virus can also cause the foot pads of dogs to become thickened and hard, hence the other name for Distemper, “Hard Pad Disease”. In wildlife, Distemper infection closely resembles the clinical signs of Rabies.

More than 90% of cases of Distemper cause death, but if a dog survives it will usually have permanent damage to the nervous system.

Who is at risk? All unvaccinated dogs are at risk, but especially puppies. Consider the risk with unvaccinated dogs being brought up from shelters in southern states…. Vaccinate!

To prevent Canine Distemper Virus, a series of vaccines are given to puppies to maximize immunity while the immune system is maturing. Also, it is prudent to avoid gaps in the immunization schedule and to keep Distemper vaccines up to date. It is wise to use caution when socializing puppies or dogs that have not been vaccinated at parks, puppy classes, daycare, obedience training and groomers.

Pet ferrets should also be vaccinated for Distemper using a USDA-approved ferret vaccine.

CANINE PARVOVIRUS…. CPV. This is an extremely contagious disease, with the highest risk animals being puppies between 6-20 weeks of age, but older dogs can also be affected. It causes acute gastrointestinal disease, and sometimes even inflammation of the heart muscle (Myocarditis).

CPV was first noted in Europe around 1976. It spread quickly and became a worldwide epidemic in dogs and wildlife such as foxes, raccoons and skunks. Once a dog is infected, there is an incubation period of around 3-7 days. The virus then attacks the lymph nodes and replicates. It progresses to attack the bone marrow, the immune system and the small intestine. Once it is located in the small intestine, it prevents absorption of fluids and nutrients and causes significant fluid loss from vomiting and diarrhea, causing severe dehydration, shock and often death.

Symptoms:

Lethargy
Depression
Lack of Appetite
Fever
Vomiting
Diarrhea (often containing blood)

Since the advent of effective vaccines for CPV this disease is a lot less common but still remains a serious problem nationwide and world wide. Vaccination against Canine Parvovirus should not be considered an option. It is a must.

CANINE ADENOVIRUS…. This virus is a part of the Canine Hepatitis Virus and also a type of Canine Infectious Tracheobronchitis. It is spread by infected respiratory secretions from dog to dog, or by contact with infected feces (poop) or urine.

Symptoms (Type 1, Hepatitis):

Fever
Abdominal Pain
Vomiting
Diarrhea

Symptoms (Type 2, Respiratory Disease):

Dry, Hacking Cough
Retching
Sneezing
Watery Nasal Discharge
Pneumonia
Lack of Appetite
Fever
Lethargy

The population of dogs that are most at risk include dogs that came from shelters, rescues, breeding kennels and pet stores.

CANINE PARAINFLUENZA…. This virus has been recognized for almost 50 years and is part of a group of infections that cause the Canine Respiratory Disease Complex. It is transmitted via respiratory secretions, from coughing, barking or sneezing, and also via fomites (bowls, collars, leashes, hands, shoes, blankets etc).

80% of exposed dogs become infected and show clinical signs. 20% may not show clinical sigsn but can still spread the virus via shedding of virus particles. There is a 10% mortality rate associated with this disease.

Symptoms:

Nasal Discharge
Ocular Discharge
Sneezing
Lethargy
Lack of Appetite
Fever

LYME DISEASE…. Everyone has heard of this one. Especially if you live in this part of the country. In fact, you may have a dog that has had Lyme Disease or you may have even had it yourself. Lyme Disease was diagnosed as an infectious condition for the first time in 1975 in Old Lyme, Connecticut. It was originally mistaken for juvenile rheumatoid arthritis. The bacterium involved was first described in 1981 by Willy Burgdorfer, hence the bacterias name Borrelia burgdorferi.

Lyme Disease is one of the fastest growing tick-transmitted diseases in the United States. The bacteria, Borrelia burgdorferi, is transmitted to an animal or person when an infected tick bites them. In 2018, greater than 318,000 dogs in the US were diagnosed with Lyme disease, up from 162,000 dogs in 2012.

Dogs can become infected with Lyme Disease at any time of the year but they are at highest risk in spring, summer and fall, when ticks are most active and people spend more time outdoors with their dogs.

Symptoms:

Lameness (often shifting from one leg to another due to joint inflammation)
Fever
Lethargy
Swollen Lypmh Nodes

The best attack against Lyme Disease is threefold:

Prevention, eg: oral preventives given monthly (such as Nexgard), tick collars (such as Seresto) or topical medications
Vaccination using a high quality/effective Lyme vaccine
Regular (annual or biannual) blood testing, usually done with a wellness examination.

LEPTOSPIROSIS…. This is another bacterial disease affecting animals including dogs and humans. It is seen with increasing prevalence in our area and it is a complicated disease because there are so many different strains (types) of Leptobacteria……

Leptospira grippotyphosa
Leptospira pomona
Leptospira icterohemorrhagia and on…..

This disease can be acquired through direct contact with an infected animal (wild animal or pet) or from contaminated soil, water or other surfaces. Urine from an infected animal contains a concentrated source of the Lepto bacteria. If your dog drinks from a puddle or water source outside, or even ingests the bacteria from any source on the ground, the bacteria can penetrate the membranes inside the nose or mouth and cause an infection. Lepto can even gain access through cuts or sores. Once the Lepto bacteria is in the environment it can persist for weeks or months in the soil. Standing water and flooding commonly cause an increase in local infection rates.

Symptoms:

Fever
Anorexia/Lack of Appetite
Muscle Pain
Vomiting
Dehydration
Cough
Lethargy
Drinking and Urinating Excessively
Weight Loss
Jaundice (yellowing of the tissues)

Because wild animals harbor and shed the Lepto bacteria and contaminate the environment, prevention of exposure is not a realistic expectation. Routine vaccination for Leptospirosis helps decrease the incidence and severity of canine Lepto. It should be considered as part of your dog’s core vaccinations if your dog is exposed to an outdoor environment, and especially as statistics show that Hunterdon County is on par with the national average of Leptospirosis cases.

BORDETELLA BRONCHISEPTICA (“Kennel Cough”)…. “Kennel Cough” can have multiple causes but one of the most common causes is a bacterium called Bordetella bronchisepticum. Other causes can also occur, alone or alongside the Bordetella infection, and are often viral, including Canine Adenovirus and Parainfluenza.

Kennel Cough exposure often occurs from crowded and/or poorly ventilated environments such as kennels or shelters. It also arises from infected dogs meeting at day care, dog parks, dog shows etc.

Symptoms:

A Persistent Forceful Cough (often producing mucus and phlegm)
Nasal Discharge
Ocular Discharge
Lethargy
Decreased Appetite
Fever

Kennel cough is usually easily treated. The vaccine is easily administered as either an injection or an oral liquid. Not every dog needs this vaccine (it is considered a non-core/not essential vaccine), but should be given if a dog is going to a kennel, day care, dog shows or any other situation where exposure to kennel cough is likely.

The vaccine is usually given annually but can be given every 6 months for dogs at high risk.

And now to the cats in our lives!

There are three vaccines usually used in our friendly feline population.

Rabies Vaccine
FVRCP Vaccine (Feline Rhinotracheitis, Calicivirus and Panleukopenia - The Feline “Distemper” Vaccine)
FeLV Vaccine (Feline Leukemia)

RABIES VACCINE…. See above.

FVRcp…. FELINE VIRAL RHINOTRACHEITIS….

This is a virus that is part of a complex set of respiratory illnesses that can affect cats, alone or together.

Symptoms:

Inflammation of nasal and sinus linings (Rhinitis)
Inflammation of tissues of the eye (Conjunctivitis)
Excessive Tear production
Salivation
Mouth sores
Fever
Sneezing
Mucus/Pus from the Eyes and Nose
Depression
Decreased Appetite

Symptoms can persist for a few days or even up to 6 weeks. The clinical signs will eventually resolve but the virus can remain in an inactive state in a cat for the rest of its life, and can be reactivated and cause a recurrence of the clinical signs at times of stress.

Transmission is by droplets in the air, such as from a sneeze, or contaminated objects such as a handler in a shelter, bowls, blankets etc.

fvrCp…. FELINE CALICIVIRUS….

This virus is often linked to clinical disease alongside Feline Viral Rhinotracheitis. The virus causes inflammation of the mouth and lungs. Some strains of the virus cause minimal clinical signs but others can cause sores and ulcers in the oral cavity and fluid build up in the lungs (pulmonary edema), and, on occasion, pneumonia. 2 strains of Feline Calicivirus can cause a short fever, leg lameness, and pain when handling affected joints.

This disease is most common in kittens aged 8-12 weeks and usually lasts between 7-10 days.

Symptoms:

Fever
Decreased Appetite
Depression
Lethargy
Sometimes Nasal and Eye Inflammation

fvrcP…. FELINE PANLEUKOPENIA…. Also known as Feline Parvovirus/FPV.

This is a disease seen worldwide in cats, but is now diagnosed infrequently by veterinarians due to widespread vaccine use. Kittens are affected most severely and infection rates remain high in unvaccinated cat populations. The causative agent is a Parvovirus (see dogs), it is highly contagious and often fatal.

Cats are infected by the oronasal route (via the nose and mouth), feces or contaminated surfaces affected by infected animals including other cats, raccoons and mink. Most outdoor cats are thought to be exposed to the virus during their first year of life.

FPV infects and destroys actively dividing cells in the bone marrow, lymphoid tissue (associated with the immune system) and intestinal cells. In young animals this also includes parts of the brain and retina of the eye. In pregnant cats it can cause abortion of the unborn kittens.

Symptoms:

Fever
Depression
Anorexia
Vomiting
Diarrhea
Dehydration
Septic Shock
Abdominal Pain
Tremors
Incoordination.

Indoor out and outdoor cats should receive the vaccination for FVRCP, but if a cat is only living indoors the frequency of vaccination can be decreased after the first few years of life. Outdoor cats should be vaccinated annually.

FELINE LEUKEMIA (FeLV)…. This is one of the most important infectious diseases of cats globally. It causes profound anemia (loss of essential red blood cells), immunosuppression and even cancer. The population of cats at highest risk are outdoor cats, un-neutered male cats and cats with co-existing disease conditions.

In the USA in 2010, it was recorded that 3.1% of cats have FeLV (Germany and Canada 3.6%, Egypt 4.6% and Thailand 24.5%). This figure increases to 9.0% in cats in the USA with bite wounds. Infected cats are reservoirs of FeLV for transmission to other cats or their offspring - most transmission occurs via saliva (fights, shared litter boxes and food/water bowls, mutual grooming) or urine of an infected individual. Young kittens are at higher risk from the disease due to immaturity of their immune system, but transmission can occur at any age and factors affecting the clinical course of the disease are complex and incompletely understood.

Symptoms:

Anemia (loss of essential red blood cells due to bone marrow suppression)
Lymphoma (a type of cancer)
Leukemia
Increased risk of other infections
Reproductive problems
Neurological Disorders
Oral inflammation and infection causing Pain, Decreased Appetite and Tooth Loss.

No cure exists.

Some FeLV positive cats can live without major disease complications for years with good care, minimal stress and avoidance of other infections. Infected cats should be kept strictly indoors to decrease the risk of exposure to other infectious agents and to prevent transmission of the Leukemia Virus to other cats. All infected cats should be spayed or neutered.

FeLV vaccines are non-core and are intended to protect cats against FeLV infection. There is no benefit in vaccinating a FeLV positive cat. The risk of exposure is used to assess if a cat should receive the FeLV vaccine, for example a cat that is negative for FeLV and has access to the great outdoors or lives with a FeLV positive cat would benefit from vaccination.

In conclusion, not all of our pets need all the vaccinations available. Core vaccines are essential for our pets to lead healthy lives, but vaccine schedules should be tailored to each individual, and a discussion with your veterinarian can help you decide which ones are needed and which ones are not. Knowledge about vaccines, in conjunction with your fur-kids lifestyle, will enable you to make good decisions regarding their health and help them to lead long and happy lives, doing what they love most.

“The love for all living creatures is the most noble attribute of man.”

Charles Darwin

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The Truth About Vaccines....