All posts tagged 'immune systems'

What Pet Parents Need to Know About Vaccines

Loving-couple-and-lab

“Vaccines are good!” “No, they’re bad!” “Do a half dose of the vaccine!” “Titer instead!”

There sure is a lot of noise surrounding vaccines for our pets, isn’t there? I don’t blame you if you think it’s confusing. Heck, I think it’s confusing and I’ve been doing it for almost 20 years. How, when, and what vaccines to use in pets is one of the most common questions I get both in person and online. When it comes to the truth about vaccines, here’s the real life, not-so-neat reality: there is no one size fits all answer. But the more we understand the principles behind the recommendations, the better equipped we are to make good decisions on behalf of our loved ones.

The immune system is complex, as is the science behind how we optimize it using various vaccinations. Here’s the basic information every pet person needs to understand.

How the Body Fights Disease

As we all know, a well-functioning body fights disease using white blood cells. However, not all white blood cells are the same! They come in three general categories:

1. Macrophages: These cells are the first line of defense. They engulf infected and dying cells, and save pieces of it to present to the other immune cells. Think of them as first responders. They save little pieces of the invader, known as antigens, as evidence from the crime scene!
2. B cells: These cells produce antibodies in response to the antigen. An antibody is a substance that helps the body fight disease in a variety of ways. For example, it can neutralize the invader, or act like a homing beacon for other types of cells to identify the invaders quickly. B cells are like Dr. Nefario from "Despicable Me" ... they don’t take part in the fight directly, but they produce all the gadgets that help the good guy win the battle.
3. T cells: These cells directly attack infected cells. They’re trained to identify a specific antigen, so it can react quickly to destroy the invader. T cells are the trained assassins of the body, honed in on their target.

After an infection is overcome, the body retains some T and B cells specific to that antigen, just in case it encounters it again. In order for those B cells and T cells to react quickly, they must have already been exposed to antigens from the infecting agent. That’s where vaccines come in.

How Vaccines Help

Vaccines imitate infection without causing the actual disease. This allows the body the benefit of those B and T cells carrying around a blueprint for how to respond to the disease, without actually having to survive the infection first. Here’s the important thing to note ... not all vaccines work the same way. Here are the most common types of vaccines we use in veterinary medicine:

1. Attenuated vaccines: These are live infective agents that have been weakened or altered in some way so they do not cause the actual disease. Distemper, parvo, and adenovirus-2 are this type.
2. Inactivated vaccines: These are whole bacteria or viruses that have been killed so they cannot replicate. The most common vaccines in this category are rabies, Leptospirosis, Lyme, influzena, FeLV, and injectable Bordetella. Because these organisms are dead, they are often combined with a substance to “draw” the immune system’s attention: like sending a flare into the sky. These substances are called adjuvants. Vaccines in this category are, according to some, the most likely to cause an adverse reaction.
3. Toxoid vaccines: These are a detoxified toxin - these are not actually in response to an infectious agent at all! Rattlesnake vaccine is the most common example.
4. Recombinant vaccines: These vaccines represent a new generation of vaccine technology. They take a piece of DNA or RNA from the infectious agent and insert it into a benign live virus that will not cause infection. Because the organism is live, it triggers a nice strong immune response without the need for adjuvant. If your cat has been vaccinated with adjuvant-free Purevax, then you’re familiar with this type of vaccine.

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How often do we need to re-vaccinate?

Well, here’s where it gets tricky. Some vaccines last longer than others because of the nature of the infection itself. Or, the exact same vaccine may last longer in one individual than in another. I have a colleague who needs a rabies vaccine every three years; mine lasted 20! There is no guaranteed answer.

So, what do we do? We make recommendations based on minimizing the number of vaccines while maximizing the level of protection for animals taking into account the wide variability in response. The American Animal Hospital Association assembled a gold star panel of the world experts in immunology who make, in my opinion, the most informed recommendations for dogs. The American Association of Feline Practitioners has done the same for cats. These are guidelines that are tailored to your pet with help from your veterinarian.

When you talk to your vet about what your pet needs, you balance risk versus benefit for the individual. You look at lifestyle, likelihood of exposure to diseases, severity of those diseases, current health, and vaccine history. The two most important factors are risk and health history.

Risk: Not all pets are at equal risk for disease. A pug who lives in a skyscraper in San Francisco is not at the same risk for certain diseases as a hunting dog in Louisiana.

Health History: A healthy one year old who is just finishing up their initial vaccine series has different needs than a sixteen-year-old diabetic who has been vaccinated on time her whole life. A sick pet, one with a history of reactions to vaccines, or one with a history of immune mediated disease will have different recommendations.

The exception is rabies, a disease that kills both pets and people. Most jurisdictions have mandated rabies vaccination guidelines written into law.

Can’t I just titer?

Titers are, for those willing to pay for them, a decent (but not foolproof) way of feeling out a pet’s immune status. Titers check for circulating antibodies to a specific disease. Remember when we were talking about B cells and T cells? Titers only tell you about long term B cell response. A pet with a high antibody titer may still be bottomed out on T cells, and vice versa. It’s only part of the picture. It’s not a guarantee that a pet is protected, but it gives you more information to make an informed decision particularly when it comes to how often to boost vaccines in an adult animal who already has several boosters.

What about half doses for smaller pets?

It’s tempting to think of vaccines the same way that we do drugs, whose efficacy is dependent on the concentration in the blood. Not so with vaccines. Vaccines work more on an all-or-nothing proposition: either they get the body’s attention, or they don’t. The degree of the response is determined by the body’s production of those T and B cells. This is the same as in human medicine: my kiddos get the same volume of flu vaccine as my husband. It’s not worth the risk to gamble with a vaccine not working, with no proven benefit.

It’s challenging to dilute a textbook’s worth of information into a single blog post, but hopefully this gives you a little background for your discussions with your vet. Vaccines, nutrition, weight control, exercise ... lots of moving parts come together to help ensure the best health outcomes for your pets. The best decisions are those you make with your trusted health care providers as a team!

Dr V
Dr. Jessica Vogelsang, DVM

References:
“Understanding How Vaccines Work” from CDC.gov
AAHA canine vaccination guidelines
AAFP feline vaccination guidelines

Infographic: 5 Ways Cats Improve Your Life

If you're lucky enough to share your life with a cat, you'll know that regardless of personality, felines make life better. Whether they're low-key couch potatoes or frenetic, live-out-loud adventurers, it really doesn't matter. Each kitty finds a way to bring happiness and companionship. But that's not all! They add a fullness of experience to life, in five amazing ways which we've outlined in the following infographic!

To view the full-size PDF, simply click on the image below. And be sure to share this post with your cat-loving friends and family ... or better yet, those who still need convincing!

PDF DocumentPDF Document

Pet Food Super Powers

Super girl and dog

Believe it or not, it wasn’t until nearly the 20th Century that pet food was something distinct from scraps derived from human diets. However, only in the past four decades has the emphasis on health-promotion entered the mix. Some of our readers will no doubt recall the “Gravy Train” commercials of the 70’s. Pet food certainly has changed dramatically since those days! More...

A Probing Look at Probiotics

Girl doing yoga

After years of hearing about the benefits of probiotics, you probably think you know everything you need to. Chances are they were your friend to help you through the winter ambush of colds. To most minds, there’s probably no mystery left.

Given the nature of the good news plus more good news, you’re either in favor of probiotics or you’re like me, a totally pro-probiotic fanatic.

But regular doses of probiotics? Hmmmm. 

Even in the media, probiotics are discussed generically, rather than mentioning the individual helpful strains of friendly bacteria. Such overgeneralizations leave us unsure if you should be taking them, which ones to take, how often to take them, and (when you just get down to it) what exactly is it that probiotics do?

Well, I’m gonna break it all down for you, demonstrating, once and for always, just how awesome probiotics can be.

First, let’s see what “the authorities” say. Probiotics are defined by the World Health Organization (WHO) as “live microorganisms, which, when consumed in adequate amounts, confer a health benefit on the host.” Probiotics are often referred to as “good” or “friendly” bacteria, and YOU are the host the WHO is referring to in this instance.

But what exactly are probiotics, you ask? Well, stay with me here.

A complex ecosystem of bacteria, known as the “intestinal microbiota,” develops after birth, taking up residence in the intestinal tract. Yep, we have a whole ecosystem of bacteria shacking up in our gut. The intestinal microbiota contains both “good” and “bad” bacteria. When the “bad” starts to outweigh the “good,” which can be due to lack of sleep, excess stress, or a bunch of other causes, it may affect your digestive system and your overall well-being.

To level off any imbalances, taking a probiotic supplement can help this whole gut situation. Maintaining a consistent level of “good” bacteria in your intestinal tract may actually improve how well it functions. Take that, “bad” bacteria!

Having adequate “good” bacteria has been shown to help support a healthy digestive system, a healthy immune system and help maintain oral health.

But all probiotics are NOT created equally. This is where it gets tricky.

There are many strains of cultures that have probiotic potential. But, each strain does different things, and each has its own little suitcase of benefits. We figure all this out in controlled studies, and we also figure out if you need a little bit or loads of a certain strain to reap its benefits.

You may have seen something on a food label (think yogurt or sauerkraut) about live and active cultures. Live cultures are microbes used to ferment foods, but not all live and active cultures are probiotics (meaning they don’t all have studies supporting specific benefits.) The “Live Active Cultures” seal was established by the National Yogurt Association to help consumers distinguish between yogurts that contain a minimum level of live and active cultures versus those that don’t.

So, bottom line, should you take a probiotic supplement?

I recommend that most people include a serving of fermented food each day (for example, kimchi, kefir, sauerkraut) and take a premium probiotic supplement as insurance for good gut health and overall wellness. When you do this and your best to adhere to a healthy lifestyle, including managing stress and getting the proper amount of Zzz’s, you may just become a pro-probiotic fanatic, too!

Keri Keri Glassman MS.RD.CDN