Pet Vaccines 103 - How Vaccines Do (And Don't) Work

So, we've talked about the diseases we commonly vaccinate for in the first (canine) and second (feline) articles. Now we'll offer up some answers for the questions we commonly field about vaccines.

How do vaccines protect my pet from disease?

That's a deceptively simple question, considering how complicated Muffy's immune system is. The basic idea is easy enough to grasp, however. In order for your immune system to fight off an invading disease, it first needs to identify it. In the cellular soup that is the living body, when something new and harmful comes along it can take some time to identify it - time you often don't have when under attack by disease. Remember how much of the town got wiped out in Invasion of the Body Snatchers before folks figured out how to tell who's who? So, vaccines contain bits of the offending virus or bacteria that have been rendered harmless, giving your immune system a "heads up" on what to look for if infected in the future. That means they can take care of the enemy before it becomes a problem, instead of wasting time trying to figure out who the enemy is.

What's actually in those vaccines?

There are three basic types of vaccines. 

• Killed vaccines are basically busted-up bits of a virus or bacteria. They contain important proteins your immune system can recognize and learn to differentiate in the future, but everything's dead so the virus or bacteria can't spread or cause disease. 
• Modified live vaccines actually can multiply in the body, but they've been altered by the kids in the lab so they no longer cause disease. These generally produce much better immunity since your immune system gets exposed to a lot more virus. 
• Recombinant vaccines take the best of both worlds - generally, a harmless virus (yup, probably the majority of viruses out there cause no real harm) is injected with a few genes that allow it to produce a few proteins that are specific to the disease we want to vaccinate against. It's sort of like a good samaritan going door-to-door with photos of annoying door-to-door salesmen so you know when not to open the door.

Are vaccines 100% effective?

Realistically, nothing is 100%, but most manufactures claim efficacy of 100% or at least the upper 90's for the "core" vaccines. Non-core vaccines like leptospirosis, FeLV, and FIV sport lower numbers but are generally still pretty good - in the case of lepto, sometimes even if disease isn't prevented, a reduction in severity could be life saving. 

It's also worth noting that a very small percentage of animals will be "non-responders" to a particular vaccine - for whatever reason, there immune system won't recognize and mount a response. Another potential reason for failure is mishandling of the vaccines, which generally are sensitive to temperature - this is the main reason buying and giving vaccines yourself is a bad idea. I threw out $800 worth of vaccines a few months back when a refrigerator died over the weekend - I frankly don't trust the kid at the feed store or the businessman running a mail-order outfit to do that.

What's "herd immunity?"

Okay, so no one's ever actually asked me about the concept of herd immunity. But it's worth bringing up here. Basically, the idea is that if you create immunity to a disease in a majority of a population through vaccination, the individuals who don't develop immunity (from failure or lack of vaccination) get a sort of second-hand protection, since you've drastically decreased the odds of them being exposed to the disease. Imagine 100 people in an office. If 90 of them get flu shots, you've just reduced the risk of exposure to the flu at the office by 90% for the other 10 folks. So, even if a vaccine isn't 100% effective for everyone, if everyone gets it they'll be well protected regardless (and that's how you end smallpox, kids). 

As an aside, this is why I tend to think of vaccination (both animal and human) as a social responsibility - those 10 folks who didn't get the flu shot are not only freeloading on everyone else's vaccines, but they're serving as a potential reservoir for the disease, too.

So, two big questions remain - how frequently should pets be vaccinated, and what are the risks of vaccinating (hint: they're a lot less than not vaccinating). We'll get to them next, but for now I'll let "herd" immunity serve as an excuse to leave you with the following video.

Pet Vaccines 102 - Common Feline Vaccines

For the the first article on canine vaccines, and a discussion of rabies, click here.

Cats are not just small dogs that will agree to relieve themselves on ground-up clay. They have their own medical (among other) quirks, their own diseases, and with the exception of rabies, their own unique vaccination needs. This article discusses those vaccines and the disease they prevent. Rabies vaccination is recommended (and legally required) for cats as well; we discussed that in the prior article on canine vaccines so I won't repeat myself here.

Feline Distemper Complex (FVRCP)
This is the standard combination vaccine for cats, along the lines of the canine "parvo combo." I'll be the first to admit all the different names and acronyms make talking about it confusing. Most vets, and their medical records, use the acronym FVRCP; I've underlined the letters that acronym comes from below in an attempt to clarify.

• Feline Viral Rhinotracheitis (Herpes) and Calicivirus: These are two separate diseases, but they are so similar in how they affect cats that we tend to lump them together. Both primarily cause transient upper respiratory symptoms - sneezing, nasal discharge, lethargy and the like (rhinotracheitis = inflammation of the nose & windpipe). Infection is permanent, and both viruses may flare up temporarily any time the animal is stressed - just like cold sores in people. Herpes commonly causes ulcers on the eyes, while calicivirus more often causes oral ulcers. Both are highly contagious between cats, so it's no surprise that many cats are infected as kittens. So why vaccinate everyone then? Well, if you don't have it you don't want it - and equally important, vaccinating everyone reduces viral spread through the population in the long run.

• Panleukopenia (Feline Parvovirus or Feline Distemper): Yeah, this one has too many names. Here's the scoop - this is very closely related to canine parvovirus, and typically produces the same sort of disease - vomiting, diarrhea, etc. In kittens it also is very effective at damaging white blood cells, hence "panleukopenia," which translates to "all white cells decreased." That's important because that means their immune system is suppressed and thus they become very likely to get secondary diseases. And, in neonates, the disease may damage the nervous system, resulting in problems similar to canine distemper. So that's where all the names and confusion come from. Fortunately, a very effective vaccine comes from your veterinarian so your cats hopefully never need to worry about those details.

Non-Core Vaccines

• Feline Leukemia Virus (FeLV): This disease primarily affects white blood cells, potentially turning them cancerous (leukemia). However, the most common effect is a depression of the immune system, leading other illnesses to be more severe and predisposing to secondary infections when sick. It is transmitted via saliva, and cats are most susceptible when young. Thus, an initial series is recommended for all kittens, and adult boosters are recommended for cats that spend time outdoors - potentially exposed to other cats. Since cats may be infected for years before showing signs, testing is also recommended for all cats when young.

• Feline Immunodeficiency Virus (FIV): In many ways similar to FeLV, FIV is basically the feline equivalent of AIDS. It is capable of dramatically depressing the immune system, leading to potentially fatal opportunistic infections. The virus must enter the bloodstream directly, making bite wounds the most common manner of transmission. Vaccinated animals will test positive, meaning there's no way to differentiate vaccination from a sick animal in the future. Considering the efficacy of FIV vaccines is somewhat questionable, vaccination is recommended only on a case-by-case basis, primarily for outdoor male cats - since guys, as always, are more likely to fight. 

So there are your kitty shots in a nutshell. The next article in the series will cover questions about vaccine types, frequency, and risks. Stay tuned!

Quick Tips For Low-Stress Vet Visits

Imagine your mother dropped by this morning with a very large box; without words or explanation she unceremoniously forced you into it, then tossed you in the car and took off. Eventually the car stops and she lugs you into the doctor's office (she's stronger than she looks, that mother of yours). She doesn't seem to understand your repeated questions, so you still have no idea what's going on or why you're here. However, several others seem to be in similar situations. Some are in boxes like you, others are tied to ropes - there's one person who won't stop shouting nonsense, another urinating on a chair leg, and one guy who won't stop trying to lick everyone in the face. Eventually you're taken into another room, dumped out of the box and onto your keister, then poked and prodded for no apparent reason by some strange woman in a white coat. They finish off with a couple of unexpected shots in the rump, then good ol' mom shoves you back in the box and drives you home.

Yeah, I guess that might be a little stressful. 

A little food cajoles most cats...

For some pets there may be no such thing as a "stress-free" vet visit, but we can reduce that stress to manageable levels. It's also important to note that animals deal with stress differently, just like people - some may growl or cower, but acting overly submissive or affectionate can be less-obvious signs too. Today's article covers several simple things you can do to make veterinary visits easier on your furry housemate's nerves (and in turn, your own).

Setting Expectations
Animals are bright, fast learners. If that cat carrier, leash, or car ride always culminates in getting poked in the butt by a stranger, it won't take them long to start freaking out at the first sign trouble is on it's way. I have one diabetic patient whose owner tells me Tiny's fine in the car if they turn left out of the driveway - but turning right always means the vet, and blood draws, and one instantly ticked-off Tiny. Fortunately, pets make positive associations just as easily, so you can undo most of this stress with a little effort.

....and the odd dog. This one
is more odd than most.

• Get in the habit of setting the cat carrier out once or twice a week with a treat or toy in it. They'll be eager to get in the next time you need to use it for travel.
• Likewise, take your dog on fun leash walks around the neighborhood regularly if you don't already.
• Once they are good with the paraphernalia, start taking your dog or cat on short car trips. Bring a food reward or two to make it fun - some fast food places like Sonic keep dog treats at the drive-thru so you can both get a little positive reinforcement.
• Placing a familiar-smelling item like a blanket in the car or carrier also helps pets relax.
• Drop by the vet clinic occasionally with Muffy, just to say hello or check their weight. Bring a favorite reward and ask a staff member to offer it.

On a related note, I highly recommend the pet carriers with snap-on tops. It's so much less stressful on everyone to just pop the top off, instead of prying Muffy out only to force her back in afterwards.

There's Stress In Numbers
Stress is additive and contagious. It's tempting to try getting all the pets in at once, and make it a family-fun event, but....Take two hyperactive kids, one mother shouting for them to calm down, then add in your incessantly barking Beagle-buddy to boot, and even the calmest Shih Tzu in the world is going to be on edge.

• Making veterinary visits an adults-only, single pet endeavor can really go a long way toward lowering the stress levels for everyone - you included. Plus, you get a lot more for your money when you can focus on asking questions and listening to the staff's recommendations without extra kids, furry or otherwise, vying for your attention. 
• If your significant other likes to argue or won't let you get a word in edgewise, get them a sitter too (my wife says her spouse is like that...). 
• On the other hand, if you are stressed out - which is okay, and often understandable - your pet will sense that and follow suit. It's always okay to ask to wait outside during the exam, and sometimes it really is less stressful for everyone.

The same strategies can be applied when choosing a vet or setting an appointment:

• Some clinics have started providing separate waiting areas for cats and exotics, since a room full of barking dogs is pretty much guaranteed to stress them out. 
• If you're flexible, asking for an appointment at a slower time of day is a good move too.
• Lastly, the discount walk-in shot clinic is almost guaranteed to have a waiting room full of chaos; that's one of many arguments for paying a little more to see the doctor down the street.

Better Living Through Chemistry
Of course, there are a few pets out there who just aren't going to adapt well to the clinic, car, or carrier no matter what you try. For those guys, there are varying levels of "chemical intervention" we can try to help them out.

What, you don't recognize Benadryl?

• Mild Anxiety: Pheromone sprays or collars like Feliway and D.A.P. may be helpful. They're also useful initially in conjunction with the above techniques to take the edge off.
• Moderate Anxiety: Ask your vet about trying Benadryl. It often provides some sedation and is quite safe for most animals at the proper dose - again, ask your vet.
• Severe Anxiety: There are several sedatives and anxiolytics that can be life-savers for dogs that truly need them; all have the potential for significant side-effects and require a prescription, however, so a good chat with your vet is in order. Furthermore, pets who need this level of intervention for a trip to the vet likely have other behavior issues that need addressed.

Lastly, but probably most important - if the stress of veterinary visits is truly tough on you and your pet, consider making an appointment solely to discuss this issue and come up with a plan of attack. You can even consider a consultation without your pet, if need be. Fortunately, though, most dogs and cats can learn to manage a trip to the vet with a just a bit of work and forethought on your part. I'm really not that bad. Plus, I have treats.

Heartworm 103 - Those Pesky Cats

Cats are not just small dogs, and feline heartworm disease is a prime example. The first two articles of this series dealt with how heartworms cause disease and preventative/diagnostic strategies primarily in relation to dogs. Today's article will outline specifically how heartworms effect cats; in many ways they are a more frustrating and elusive problem in cats, made all the more dangerous because many owners don't realize feline heartworm is a serious concern.

Accidental Guests: Heartworm Disease in Cats

Cats are not the natural host for heartworms. Unfortunately, no one seems to have explained this to the mosquitoes that spread infection or the heartworm larvae that cause it. Consequently, these uninvited and unadapted parasites really, really tick off the cats immune system. The first consequence of this is positive - cats seem much better than dogs at killing off larvae before they develop into adults. Studies suggest only about one-third to one-half of naturally infected cats develop adult worms, though it's tough to nail down accurate percentages due to the difficulties in testing that we'll go into later. 

Hey, human. Indoor cats get
heartworms too.

The second consequence of cats' super-miffed immune system is a negative one, however. Killing off the larvae within the lungs results in significant inflammation. Vessels and lung tissue gets thickened, making blood flow and air exchange less efficient and resulting in the classic signs of respiratory disease - coughing, rapid or labored breathing, and general malaise. This is now referred to as heartworm-associated respiratory disease (HARD), and it is a major reason why I've started recommending all cats receive monthly preventatives. Depending on the studies you look at, perhaps as many as 15% of cats in some areas are exposed to heartworms and thus at risk for HARD - even if they never develop adult worms. And if you think your kitty is free and clear because it's indoor only, think again - in one published series of cases, 27% were indoor-only cats.

What about the ones who do develop adult worms, though? Whereas dogs may have dozens of adults, cats rarely have more than two or three - again, their immune system is pretty good at whacking those larvae. This means many cats with adults have such a low burden they may show none of the cardiovascular problems typical in dogs. The caveat to this is that when those adults die off after a year or three, the dead worms are big enough to block off major lung vessels - and between that and the cat's once-again huge inflammatory response it can be enough to quickly kill them. Indeed, most veterinary texts list "sudden death" as a major "sign" of feline heartworm infection. That's not the way I like to diagnose things.

Diagnosing Heartworms in Cats...

...is really, really frustrating.

In the second article we talked about how the main test used to diagnose heartworm in dogs looks for a protein produced by adult female worms. This test works equally well in cats, if there is an adult female worm. In one study on naturally infected shelter cats over 50% had only a single worm, and none had more than four. This means cats are fairly likely to have male-only infections, and thus come up negative on this test - even though a single male could potentially kill them. 

Cats aren't good at tests.

Even more importantly, a lot more cats will develop the serious respiratory disease discussed above (HARD) without ever developing adult worms. On the bright side, there are antibody tests available that check for exposure to heartworm larvae. These would be great for diagnosing HARD or even male-only adult infections...except studies suggest they aren't that sensitive and miss many exposed cats, maybe more than 50% of them. 

Not surprisingly, I don't spend much time screening outwardly-healthy cats for heartworm. I'll run both tests when I suspect a cat has HARD or adult worms...but if they're negative, I don't cross heartworm off the list. Chest x-rays or ultrasound of the heart can be useful, but diagnosing feline heartworm can be elusive even when you're sure that's the problem.

Treating Feline Heartworm

Here's a quick topic. Remember how one dead adult may be enough to gunk up the lungs and cause sudden death? We can kill the worms easily enough, but we're just as likely to kill the cat. Yeah...we don't treat feline heartworm. "Treatment" is pretty much relegated to using anti-inflammatory drugs to control the signs and hoping for the best when the worms do die off. It's pretty frustrating when you find yourself crossing your fingers and wishing a freeloading parasite a long, healthy life.

Heartworm Preventatives for Cats

Most veterinarians used to be wishy-washy at best about recommending monthly preventatives for cats because adult infections were relatively uncommon, and serious complications (like death) even moreso. But the respiratory complications - which can potentially be life-threatening themselves - are looking more and more common. Complicate this by the fact we don't have a great diagnostic method  (meaning we likely are underestimating prevalence) and hopefully you're starting to understand why I've started recommending all cats stay on a monthly preventative. 

As of this writing, there are two topical products and two oral products on the market, and all are effective for heartworm prevention. Both topicals are great products, covering fleas and some common intestinal parasites while sparing you the adventure of trying to get a pill into a cat. Neither oral product covers fleas, but Interceptor covers several of the more common intestinal parasites. It's a good alternative in areas where fleas aren't a concern as it's a fair bit cheaper than the topicals.

I've covered a lot of ground in these three articles, and in a good bit of depth. If you're not 100% convinced that heartworm is a serious risk that warrants monthly preventatives, I'm happy to address any lingering questions or concerns in the comments section below!

Bad kitty! Or…sad kitty?

Litter box problems, or “inappropriate elimination behaviors," are among the most common complaints I hear from cat owners.  If it has ever happened in your home, you're probably thinking “inappropriate” is a rather mild way to describe urine or feces in the middle of your carpet, but bear with me.  With some investigative work and patience, we can help most cats get over bad bathroom behavior. And, with the right information you may prevent future problems.

Medical causes

The first step in these situations should always be a visit to your vet to rule out underlying medical causes.  Conditions like kidney disease, diabetes, and hyperthyroidism can increase urine production, while urinary tract infections and bladder stones are uncomfortable and may result in frequent urination.  Likewise, issues such as parasites, constipation, and inflammatory bowel disease may make defecation urgent or uncomfortable.  Even arthritis can affect bathroom habits – imagine if you had to climb over a waist-high wall to get to the toilet!  So, it’s possible your feline friend doesn’t feel well and just can’t make it to the litter box.  A thorough physical exam, blood work, urine analysis and/or fecal exam will establish your cat’s general health status and help guide treatment if necessary.

Unacceptable, Human!

Behavior

Now that we’ve ruled out medical conditions, it is safe to start questioning behavioral causes… But before you send kitty to a psychiatrist to work out his anger issues, we need to talk about YOUR behavior too.  You may think that your cat doesn’t deign to notice you unless it’s dinner time, but cats are actually quite sensitive critters.  They can’t tell you with words that they are stressed out by something in the house, but peeing outside the litter box is one way to get your attention (my two cats prefer to barf in my shoes or self-mutilate, respectively).  Here are some things that might be ruffling kitty’s tail feathers.

Litter box issues:

• Hygiene – Is it possible that you and kitty have different standards when it comes to cleaning the bathroom, so he decided to seek out a cleaner facility?  Most cats are quite fastidious, so litter should be scooped daily and changed out completely on occasion (non-clumping litter should be dumped every few days). You might also consider tossing your box for a new one if it’s really worn, as plastic can retain urine smells.
• Availability – Are there enough litter boxes in the house?  I recommend having one box per cat plus an extra (e.g. 3 cats, 4 boxes) unless you have a very large number of cats, and then you will probably get into trouble despite the number of boxes.  There is a scientific study from the 80s showing that individuals with 10 or more cats have a 100% probability of becoming a victim of inappropriate urination, and a 90% probability of eventually being a crazy cat person (ok, maybe only the first half was shown in the study).
• Location – Maybe kitty was just settling down in his laundry room litter box to “read the Sunday paper” when that really loud timer on the dryer buzzed and startled him into Tuesday.  If you think location could be the problem, leave the current box in place but add one somewhere else in the house.
• Type of litter – Cats have preferences about their potties, and it may be your cat doesn't care for that fresh pine scent as much as you do.  Try a few different types (clumping, clay, recycled newspaper, etc.) at the same time to give kitty a choice of textures and smells.  Be sure to include a finely-textured clumping litter in your test, as it was chosen more than twice as often as other types in a thorough study by behaviorist Dr. Peter Borchelt.
• Type of box – Try out a new box shape or size.  However, a word of caution on covered boxes…  Many people favor covered litter boxes for obvious reasons, but I find most cats do not, especially in multi-cat households. For example, my cat thought his sister was playing hide-and-seek in the covered box we used to have, so he would wait outside and ambush her upon exit.  Needless to say, she did not enjoy this.

Environmental stressors – Pretty much any event or change in your cat’s life can fall into this category, but common issues include:

• New people – Houseguests, new spouse or roommate, new baby, etc.
• Disruption of environment – Moving, renovations, holiday decorations and celebrations
• Change in your schedule – New job, leaving for vacation
• Visiting the vet – I wish they all loved seeing me…
• Inter-cat aggression – self explanatory, and common.
• New pets – Introducing a furry family member can be a very delicate process, and strategy may depend on the personalities of your current critters. I recommend talking to your veterinarian if you are thinking of adding a pet.

These issues are tricky, as it’s often difficult to control them unless you plan on letting your cat completely run your life.  What you can do is implement some practices that will hopefully make kitty more resilient to life’s little blips. We've already discussed litter box recommendations, but additionally all cats should have fresh food and water, something they’re allowed to scratch, and a safe space where they can go to get away from other pets and people if they choose.  Perches can often provide such a space, and when placed near a window also serve as a source of entertainment.  You should also carve out some time each day to interact with your cat via play, grooming, or even training (yes, cats can be trained!).  Toys and catnip are great stimulation for some kitties, while others will be engrossed by “cat TV” or nature videos.  Feliway (http://www.feliway.com/us), a synthetic pheromone product, may also help reduce stress.  Be creative and try different things to find what lights your cat’s fire, but the message is that your cat may be bored or stressed if his basic needs are not met, and this can lead to health and behavior problems.  Ohio State University's Indoor Pet Initiative (http://indoorpet.osu.edu/cats/) has done a lot to further our understanding of how environmental enrichment can help our feline friends live happy lives.

No dice, Doc.  Now what?

So you’ve had kitty vetted, offered a Pu-Pu platter of litters and boxes, enriched his life and pheromoned the heck out him, and he’s still “thinking” outside the box.  Now may be the time to head back to your veterinarian, or a veterinary behaviorist if one is available and finances permit.  If the problem has been going on for a long time or your cat is particularly sensitive to environmental stressors, finding a solution can be very specific to the individual animal and situation.  There are anti-anxiety medications that can help, especially in cases where feline housemates are not getting along, but they are not magic pills and must be used in conjunction with environmental modifications, many of which have been discussed above.

To sum up…

• Rule out medical causes
• CLEAN the litter box
• Try different types of litter in different boxes in different locations
•  Reduce stress with environmental enrichment and interaction with your cat
• Medications can be useful in conjunction with behavior and environment modifications

-Dr. Courtney Smock