Parasites: Know your pets' uninvited guests

Berma loves the outdoors! Unfortunately, parasites love that he loves the outdoors.

When you think of summer, you think of lazy days, outdoor fun, and maybe a barbeque or two; and if you’re a pet lover, your four-legged friend is probably a welcome guest at any or all of your summer adventures.  Your pet might be bringing some uninvited guests along, too, though, of the creepy-crawly variety.  Summer is peak season for parasites, and it’s important to your pet’s (and sometimes your) health that you know how to recognize those nasty little guys and keep him protected. 

[NOTE: Having said that summer is the peak of parasite creepiness, it's also important for us to say that while parasites may seem fairly seasonal, parasite prevention shouldn't be!  Keeping your pets on parasite prevention all year (even when you think you don't need it) is recommended by the AVMA, and we agree 100%.  It is especially important to keep your heartworm prevention schedule running all 12 months out of the year.]

First off, a little vocabulary!  Parasites can be divided up into two groups: ectoparasites and endoparasites.  Ectoparasites live outside of your pet; endoparasites are internal.  Common ectoparasites include fleas, ticks, mites, and mosquitoes.  The endoparasites to watch out for are roundworms, tapeworms, heartworms, and microscopic baddies like hookworms, whipworms, coccidia, and giardia.  

Common Ectoparasites

Knowing you have a problem is half the battle, and the nice thing about ectoparasites is that they’re easy to see.  Here's a breakdown of the common ones, and what to do about them.  

Fleas 

Cat flea (Ctenocephalides felis)

The most common type of flea, for both cats and dogs, is the cat flea (Ctenocephalides felis).  You may not always see the actual fleas on your pet, but luckily they leave behind a dead giveaway in the form of flea dirt: little black, crusty specks stuck in the base of a pet’s fur that are basically little bits of dried blood that the flea has digested and excreted (yes, it's flea poop).  If you want to make sure that what you're seeing is flea dirt, get a couple of little specks wet; flea dirt dissolves into what looks an awful lot like blood (surprise!).  Aside from being an itchy annoyance, fleas cause serious allergies, secondary infections when scratching breaks the skin, and hair loss; and they spread disease – tapeworm eggs are spread by fleas, in fact.  

Fleas are designed to be difficult to get rid of; their flattened body shape makes them hard to scratch or brush off, and their ability to jump hundreds of times their own height makes it easy for them to spread.  Plus, fleas put the fabled reproductive abilities of rabbits to shame; a single female flea can lay 40-50 eggs per day.  Yuck.  

Flea dirt in a pet's fur

There are lots of products and practices out there that claim to get rid of fleas, and most of 'em don't work.  Flea baths and baths with dish soap may kill the adult fleas on your pet, but do not address those 40-50 eggs per day.  Flea collars, in addition to being highly toxic and potentially dangerous, only kill fleas in the head-and-neck region.  Over-the-counter flea and tick products sold at grocery stores may be cheap, but they're also typically ineffective, and can be dangerously toxic.  And many all-natural, do-it-yourself remedies are ineffective and contain potentially dangerous ingredients, such as garlic, which is actually toxic to cats and dogs.  The best way to take care of a flea problem is to purchase a vet-recommended flea and tick preventative product and stick with it every single month, all year round.  This should be a part of your absolutely-essential, never-skip-it pet care routine if your pet ever sets paw outside or interacts with other pets, because that's all it takes. 

 
Ticks
Ticks come in all shapes and sizes; around here, the American dog tick (Dermacentor variabilis), lone star tick (Amblyomma americanum), and deer tick (Ixodes scapularis) are all common. The deer tick is of particular concern, because it can spread Lyme disease, not just to your dog, but to you as well.  For a great, interactive tick ID guide, click here.  Pets pick up ticks as they walk through grass and underbrush, and they're exceptionally good at finding hosts.  This is because they're equipped with fancy sensors, located in their front legs, called Hallers Organs, that can detect heat and carbon dioxide - AKA mammal body heat and mammal breath.  Ticks crawl up to the top of a piece of grass or a twig and hold out their front legs, and when they sense something mammalian coming their way they simply grab on and have a meal on the go.  

Lone star tick (Amblyomma americanum) looking for a meal

To remove an embedded tick:
--Use tweezers to grab it as close as you can to your pet’s skin, and 
--Pull slowly and steadily; if you yank hard, the tick’s head may break off and remain under the skin. 

Here's what not to do: cover it in vaseline or nail polish, freeze it, or apply a hot match to it.  None of these methods are particularly effective, and all risk causing further harm.  And never, ever grab an embedded tick by the body or squeeze it!  Doing that forces potentially-diseased blood out of the tick and into the host.  Once a tick has been successfully removed, there are a couple of effective ways to kill it: drop it in rubbing alcohol, or, if you have a flair for the dramatic, burn it (they pop...it's kind of horrifying, honestly).   

Protecting your pet from ticks is, as with fleas, an easy task, and there's really no excuse for not doing it - just do exactly what we described above for fleas.  Most parasite preventatives are multi-purpose products, so ask your vet to recommend one that takes care of both fleas and ticks.  It's the one-stop-shop of preventive care. 

Mosquitoes
If you're a mammal, you probably find mosquitoes irritating.  If you're a dog or a cat, they're a little more troublesome than a few itchy bumps, though.  Mosquitoes are an intermediate host in the life cycle of heartworms, and they're the ones that move those nasty, dangerous endoparasites from one pet to another.  Every pet that comes into contact with mosquitoes should be on a monthly heartworm preventative, but to be extra cautious, talk to your vet about choosing a parasite preventative that repels mosquitoes in addition to getting rid of all those other creepy critters. 

Common Endoparasites

These guys are, by nature, more difficult to detect than their external PICs (partners in crime...yeah, we're on the abbreviation bandwagon); some are even impossible, since they're microscopic.  There are some common symptoms to look for, though: irregular or bloody bowel movements are a good indicator that something might be up, as is scooting on the carpet and general itching or licking around the butt-region.  If any of these symptoms crop up, it's time to collect a stool sample (fun!) and get it to your vet for a fecal exam.  Left untreated, intestinal parasites can do serious damage to your pet; malnutrition can lead to organ failure, and dehydration from persistent diarrhea can be a killer.  There's not always a foolproof way to prevent your pet from picking up intestinal parasites, so recognizing the symptoms and seeking care right away is crucial. 

Roundworms

Roundworms (Toxocara canis)

Roundworms are spread by feces-to-mouth interactions, which are all too common in the pet world (and scarily common in the human one).  There are many kinds of roundworms; the most common in cats is Toxocara cati, for dogs, Toxocara canis, and for both, Toxascaris leonina.  All three are sometimes visible in the feces or vomit of an infested animal; the adult worms are long, thin, and unsegmented.  Think spaghetti.  Gross, gross spaghetti.  Roundworms are also extremely common in puppies and kittens, particularly if mom has been roughing it outdoors; distended, swollen bellies are another sign that roundworms may be present.  The best way to protect your pet from roundworms is to do your best to maintain a clean environment: pick up that poop!  Roundworm eggs are extremely hardy and can live outside of the host for a long time - think months or years - so old poop can still be risky poop.  Unfortunately, any pet that goes outdoors is probably, at some point, going to come into contact with another pet's poop; luckily, there are affordable, effective oral medications that make short work of roundworms, so there's a quick fix available if you need it.

   

Partial adult tapeworm (Diplydium caninum)

Tapeworms
Tapeworms (in pets, Dipylidium caninum) are a little more creative with their life cycle than their roundworm brethren; in order to get ready for life inside a cat or dog, they have to spend a little time inside a flea, first.  So, if your pet has fleas on the outside, odds are good that he's also got tapeworms on the inside.  Tapeworms are long, flat, and segmented; whole worms resemble (surprise!) a piece of tape, but what you're more likely to see in a pet's feces are the proglottids.  Proglottids are single segments full of eggs that are capable of moving on their own; they break off from the adult worm with the goal of crawling off to be closer to a new potential host.  Proglottids look like grains of rice, and can often be spotted either in a pet's feces or in the fur around its anus.  

As with roundworms, there are great, tried and true medications on the market that will clear tapeworms right up, but why treat what you can prevent altogether?  Just stick with your flea prevention routine all year round, and your pet's chances of picking up tapeworms are pretty slim.  The only caveat is that a pet without fleas can still pick up tapes by ingesting fleas off of another pet; cats are especially prone to this because they're so keen on social grooming.

Microorganisms

Giardia lamblia under a microscope

These are the tricky ones, because they're the lurkers.  You won't see them with the naked eye, and some are even difficult to spot under a microscope.  But being tiny doesn't make them any less dangerous for your pet.  Some, like hookworms (Ancylostoma ceylanicum, Ancylostoma tubaeforme, Ancylostoma caninum), whipworms (Trichuris trichiura), and coccidia (Isospora felis, Isospora rivolta) are spread by contact with feces; others, like giardia (Giardia lamblia), can live in dirty, stagnant water and spread when a pet stops to take a drink.  Although they are undeniably tiny, these endoparasites are also undeniably mighty; they can cause blood loss and do serious damage to the intestines, cause malnutrition, and lead to dehydration.  There are effective medications readily available, but left untreated, they can be deadly.  If you're seeing funky poop and you don't know why, grab a stool sample and have a fecal exam done; under a microscope and a trained gaze, your vet can identify the culprit(s) and get your pet healthy. 
Like roundworms, the key to keeping your pet safe from microscopic parasites is hygiene; maintain a clean living space and make sure your water supply is fresh.  You may not have much control over how clean public spaces are, but you can make sure your pets aren't getting exposed at home. 

Heartworms

This is what a fatal case of heartworms looks like.

Heartworms are also endoparasites, but they're sort of in a league of their own.  Instead of living in your pet’s digestive tract, they live in the heart and lungs, making them a more immediate threat to your pet’s life.  Making heartworms even more dangerous is the fact that pets who are infested often show no symptoms until their situation is dire; by the time a pet is coughing and struggling for breath because of a clogged heart or lungs, the prognosis is usually not good.  Keeping your pet on monthly heartworm preventative is absolutely critical; like regular flea and tick prevention, it is one of the most basic measures you can take to keep your pet healthy, and it should never be thought of as “optional.”  Since heartworms are spread by mosquitoes, and mosquitoes get just about everywhere, every pet is at risk (although the risk is greater for outdoor pets, for obvious reasons).  A strict heartworm prevention schedule is made all the more important by the fact that heartworm treatment and recovery is a costly, stressful, dangerous process that some pets do not survive.  When it's so simple to protect your pet, there's no excuse for exposing him to something so deadly.  Prevention is the best treatment, hands down.  And it doesn't hurt to include a heartworm test in your pet's annual vet exam so you can catch it early in the event that he does get exposed.  To learn more about heartworms, visit the American Heartworm Society's page here.

All of this is grossing Delilah out a little, honestly.

If all of this leaves you feeling creeped out, we're sorry.  But just think how prepared you are to protect your pets from parasites!  They'll have longer, healthier lives to spend thanking you for it, and you'll get to avoid constantly dealing with these creepy critters in person.  If that's not a win-win, we don't know what is!  The parasites might disagree, but they don't get a vote.  

Photos, top to bottom, courtesy of Richard Labunski (WHS volunteer), http://billclarkbugsperts.com/, http://test.enr.state.nc.us/, WHS staff, http://www.cdc.gov/, http://www.asah.net, and Jodi Dodman Wilson (WHS volunteer)