Buggin' Out! Parasites 101
Updated: Nov 14, 2018
Nothing is scarier than learning there are creatures living and feeding on your pet. Yes, I’m, of course, referring to parasites. Worms, fleas, ticks, mites; the list of creepy-crawlies is horrifying when you’re a pet-owner. Although a terrifying topic, parasites are important to be aware of to keep your pet as protected as possible.
Almost every pet owner knows about fleas and ticks; two parasites referred to as ectoparasites because they dwell outside of their host’s body. These parasites are extremely annoying and can be dangerous as well. Both fleas and ticks are blood-suckers. They burrow their way through the fur to the animal’s skin and bite, feeding on the blood of their victims. Fleas, especially, are extremely itchy and irritating, migrating across the body, biting, breeding and defecating on their hosts. Ticks, however, find a single area to latch onto and begin leeching blood from their host until their body is engorged with blood. Aside from the obvious irritation that these pests cause, their real threat is that they can also transmit diseases and even other parasites to their hosts! The plague, cat-scratch disease, and murine typhus are a few flea-borne diseases and they also can carry multiple types of tapeworms, many of which can be transmitted to humans as well as pets. Ticks on the other hand, which are commonly found in Colorado, are responsible for the majority of reported cases of parasite-borne diseases in the US and more new diseases emerge every year. Lyme disease and Rocky Mountain Spotted Fever are two of the more well-known diseases.
Another ectoparasite of threat to your pet is mites; microscopic arachnids which live on the surface of the skin. Although irritating and quite frankly, the scariest thing to see under a microscope, they are usually not as dangerous as ticks and fleas when it comes to the transmission of disease or worms.
Ticks, fleas, and mites are extremely resilient creatures, adapted through millennia of evolution to survive on a variety of warm-blooded hosts and withstand extreme conditions. Luckily, tick and flea prevention are now made much easier through a preventative medication which we carry here at Family and Friends Veterinary Care. “Credelio” is a once-a-month chewable tablet for your dog which kills fleas within 12 hours and ticks within 48 hours. Furthermore, it provides flea and tick prevention for a whole month. It is highly palatable and is much more effective and safer than flea shampoos and topical medications. Although it does kill mites as well, it can take up to a couple months to fully eradicate them, and there are other methods which are more efficient for the treatment of mites which we also can provide here at the clinic
Now, we move on to the spookier of the parasites; the endoparasites. These parasites are made much scarier by the fact that they dwell within their host, as opposed to on the surface. I am, of course, referring to worms AKA helminths, which are divided into three subgroups: nematodes(roundworms), cestodes(tapeworms) and trematodes(flukes).
Nematodes most resemble a typical worm, with long unsegmented bodies. There are over 12,000 known species, some of which feed on plants and some aren’t even parasitic. The more well-known ones include hookworms, pinworms and heartworms. They live in all types of ecosystems including deserts and even Antarctica. Nematodes are extremely resilient creatures and even reserve the ability to become dormant and shut down their bodies, essentially dying, only to revive themselves when living conditions become more favorable. They all possess sharp, tooth-like structures which they use to pierce and latch onto their hosts, sucking out nutrients. Although most species of nematodes are microscopic, the largest, Placentonema gigantisma, which dwells within sperm whales, can grow up to forty-two feet in length. Roundworms can be transmitted when a pet eats or sniffs the feces of an infected animal, or if a pet consumes an animal infested with roundworms. Toxocara Canis, whose definitive host are dogs, pose the greatest threat to puppies or young dogs, whose development may be permanently hindered by the roundworms. Visible symptoms of roundworm infection in puppies may include bloated “potbellies,” stunted development or recurring diarrhea. All pregnant dogs and puppies should be treated with a dewormer medication routinely. Thankfully, there are many broad-spectrum dewormers which can eradicate and prevent most nematodes. At Family and Friends Veterinary Care, we carry “Interceptor Plus,” which is designed as a preventative for heartworm, but also prevents these other nematodes as well. Giving your dog a monthly heartworm preventative is extremely important because although it does kill heartworm larvae, it is unable to kill adult heartworms, which can only be killed through a lengthy, damaging process involving an arsenic(poison) based medicine which can sometimes be unsuccessful and may require further treatment through surgery.
Tapeworms (cestodes) are unique in that their body is long and flat and made up of segments that each contain their own reproductive system. These worms latch onto the intestines of your dog or cat and may cause diarrhea. Although they generally don’t cause any significant harm to your pet, they aren’t particularly pleasant, especially when you notice the small worm segments falling out of your pet’s behind. These segments, called proglottids, are shed containing eggs, which can then be ingested and passed along to another animal. These worms can be treated with a dewormer medication.
Trematodes (flukes) require an intermediate host for development which can be fish, reptiles, amphibians, snails or others. They are transmitted when an animal, like a dog or cat, ingests the infested animal along with the worms. There are many different species which dwell in different parts of their hosts’ bodies including the intestines, liver, lungs, kidneys or gallbladder. Some species can cause severe damage to these organs with symptoms including inflammation, hemorrhages, diarrhea, weight loss, vomiting, lethargy, coma and even death. Due to the fact that many of the intermediate hosts for these worms dwell in moist, swampy areas, they are much harder to be transmitted than nematodes. They too can be treated with a dewormer medication.
Not all flukes are horrifying blood suckers. These flatworms pictured below are just 3 of many species of aquatic helminths. See this video of a polyclad flatworm gliding through the water: https://vimeo.com/19200326
A couple more notable endoparasites which affect pets include giardia and coccidia. These are microscopic organisms which can be transmitted through the ingestion of feces, soil or water containing the parasite. Giardia and Coccidia are protozoan/single-celled endoparasites. Both of which can cause moderate to severe diarrhea and gastrointestinal irritation leading to dehydration especially in puppies. Some animals can live with these parasites without visible symptoms for their whole lives, although giardia and certain coccidia species are transmissible to humans and should be treated to avoid further transmission. Both parasites are also extremely common and can be treated with medications like dewormers.
When it comes to parasites and your pet, you can’t be too careful. Some parasites can be virtually harmless, but others can prove fatal to your pet. In addition to being observant for any changes in behavior in your pet, like excessive itching or scratching, lethargy or sleepiness, and occasionally take a look at their poop just to make sure everything looks normal. Worm and flea/tick preventative medicines are so important to keep your pet protected from certain parasites, but they should not replace semi-annual wellness exams with the vet. It is crucial to make sure you get your pet’s blood and feces checked for parasites at least once a year. You never know what your pet may have gotten into in the backyard when you weren’t looking. Parasites are just plain gross. Let’s make sure they stay away from our pets!