It's not something that any dog owner wants to think about, but our sweet, precious little doggies can be afflicted by some seriously disgusting -- and seriously dangerous -- health problems. Worms and worm-like parasites fall into this category. Most of them can infest your dog's intestinal tract, although they can also affect other organs. Most worms are acquired in one of two ways: Your dog consumes something containing the worm or its eggs (such as feces or infested water), or he's bitten by a carrier like a flea or a mosquito.
Regardless of the type of worm, the best remedy is prevention. Clean up after your dog promptly, keep him from eating feces -- including his own -- and don't let him drink from ponds, streams or lakes. It's also important to make sure that he's on preventive treatment for fleas and ticks, as well as heartworm (there are even some combination medications for all three). But how do you know if your dog has worms? In the case of a worm such as tapeworm, you may actually see shed segments -- pieces of the worm's body -- in your dog's feces. However, in most cases, it's more likely that your dog will have symptoms like diarrhea, vomiting or lethargy, all of which can point to a host of different conditions. Typically, your vet will need to test a stool sample or do a blood test to definitively diagnose your dog with worms and determine the best course of treatment.
In this article, we'll take a look at the common types of worms and worm-like parasites that can affect your dog. It won't be pretty, but learning how these nasty critters get into your dog in the first place -- and what symptoms might manifest -- can help your dog become worm-free sooner rather than later. And in some cases, it can save his life. On the next page, we'll start off with some worms that aren't actually worms at all.
Coccidia and Giardia: Protozoal Parasites
There are two different types of worm-like organisms that can infect your dog and cause some serious problems: coccidia and giardia. Coccidia is a single-celled microscopic organism that causes an infection called coccidiosis; luckily it isn't a common one. However, if you have a young puppy he may be infected because it can flourish in crowded, unsanitary conditions. Coccidia can also infect older dogs that have compromised immune systems due to another illness. The eggs are shed in the feces of infected animals and contaminate water, food or the environment. After they're consumed, the eggs hatch in dogs' intestinal tracts. They can also lie dormant in the tracts of dogs who are otherwise unaffected (but continue to shed the eggs in their feces) and become activated when a dog experiences severe stress.
Once they swing into action, however, these little protozoans start doing their dirty work, causing diarrhea, weakness, lack of appetite, anemia, and dehydration. The diarrhea can bloody and severe, and dehydration can lead to death. Most cases of coccidiosis are mild, however, and clear up with a few weeks of sulfa drugs and antibiotics. Good hygiene is the key to containing and preventing coccidiosis. Pick up your dog's stool immediately and keep him from eating stool. Also try to keep down the rodent and insect population around your house, because both cockroaches and mice can be carriers. If your dog is diagnosed with coccidiosis, thoroughly clean his living area using a 10% ammonia solution, steam or boiling water.
Giardia is another pesky protozoal parasite -- and unlike coccidia, it can affect people as well as pets. However, giardia is somewhat mysterious. We aren't quite sure how many types there are, and whether the type that infects dogs can infect humans and vice versa. Some vets disagree on how best to treat an infection (known as giardiosis). Giardia is often waterborne, entering the water supply through contamination by wild animals, dogs, and people. Instead of eggs, they are in the form of cysts that activate in the small intestine. Then the parasite divides itself, forms more cysts and is shed in feces. Both dogs and people can have giardiosis but not have any symptoms. The most common sign is diarrhea, which may appear bloody or slimy. It can be hard to detect, so some vets will treat for giardiosis if there is no other obvious cause for diarrhea. The most common treatment is an antiprotozoal drug. Protect your dog by not letting him drink from streams, rivers, or lakes, no matter how clean they may look.
Heartworm is a misnomer -- they can actually affect the lungs and other organs too. Read on to find out why this worm can be deadly.
Heartworm: The Deadliest Worm
Although all of the worm and worm-like parasites we cover in this article can theoretically lead to death if untreated, heartworm ranks as the most dangerous. In fact, it's probably the most deadly parasite that can affect your dog. Heartworm was once mostly found in hot and humid areas, and in dogs who spent a lot of time in the woods, but it's now running rampant across the United States. And it all begins with a mosquito bite.
When a dog is bitten by a mosquito infected with heartworm larvae, the larvae enters his skin and begins its lifecycle, eventually riding through the dog's bloodstream to the right side of the heart as well as the lungs and surrounding blood vessels. It takes about seven months for the worm to mature. If not detected, the growing population of adult worms can create a mass that blocks blood flow and ultimately cause organ failure. The adult worms also breed and produce offspring called microfilaria. They circulate in the dog's bloodstream, and can be sucked up by a mosquito that bites him. Within a few weeks, the microfilaria develop into infectious larvae. The next time the mosquito bites another dog, these larvae are passed along and the cycle begins all over again.
Dogs infested with heartworms may go for years without showing any symptoms of infection, and adult heartworms can live for up to seven years. An early sign of heartworm infection is a deep, soft cough that gets worse with exertion. As the cycle progresses, the dog can become lethargic, loses weight, and may cough up blood. In the later stages of heartworm disease, dogs can retain fluid and develop congestive heart failure. Without treatment, they'll die.
The good news is that heartworm infestations are completely preventable. Your vet can recommend a preventative -- usually a monthly chewable pill -- to give your dog so that you'll never have to worry about this deadly disease. Heartworm infestations are diagnosed through a blood test, and the treatment for a full-blown case of heartworms is very stressful. It consists of several painful arsenic-based injections, which kill and break up the adult worms into tiny pieces. A dog undergoing heartworm treatment must be kept confined and quiet, because these worm pieces can block vessels during strenuous exercise and cause death.
Many heartworm preventative medications also protect against other worm infestations, including tapeworms and whipworms. Next, we'll look at how flea bites and just being in the wrong place at the wrong time can lead to more intestinal worms.
Tapeworms and Whipworms
Flea bites are bad enough by themselves, but did you know that the flea can also transmit tapeworms to your dog? The head of the tapeworm hooks onto a dog's intestine and begins producing a series of flat egg-filled segments, resulting in a single worm with a length that can vary from a few inches to several feet. The most common way of diagnosing tapeworm is finding these segments -- which look like grains of rice -- in the dog's feces or clinging to the fur around the dog's anus. Fleas eat the dried segments, and the eggs mature into larvae inside them. Then the flea bites your dog and the cycle begins again.
Since tapeworm eggs are shed in the segments, a fecal exam can easily miss an infestation. Younger dogs with tapeworm infestations may have diarrhea and vomiting. Some dogs with tapeworm infestations scoot (drag their rear ends on the ground), but it's more likely that they have another irritant such as an impacted anal gland. If you suspect a tapeworm, look for the segments in your dog's feces. Your vet can provide a deworming pill which kills the tapeworm. To prevent an infestation in the first place, make sure your dog is on a flea control medication,
He may also pick up tapeworm eggs from eating raw meat or infested rodents, so avoid feeding him the former and letting him "play" with the latter.
Whipworms are also named for their appearance. They're thin with a bulge at one end, and look like tiny whips. Dogs pick up whipworm eggs from the environment, as they're shed in the feces of other animals. The eggs hatch in their intestinal tract, where the worms latch onto the wall of the large intestine and start producing eggs all over again. Like other kinds of worms, whipworms typically only cause severe symptoms in young or immuno-compromised dogs. A heavy infestation may cause diarrhea, anemia, or weight loss. In rare cases it can lead to death.
Once again, treatment is a simple medication, usually repeated at least once to catch any recently hatched worms before they reinfect the dog. Since the eggs are shed in the infected dog's stool, prevention is a matter of common sense and common courtesy. Pick up after your dog and keep him away from the stools of other dogs. Regular fecal exams -- twice a year is best -- will catch a case of whipworms before it gets out of control.
In our last section, we'll look at two more common worms that may plague your pup: roundworms (yep, they're round) and hookworms (which literally hook onto the skin).
Roundworms and Hookworms
Roundworms are the most common worm infestation in dogs, especially young puppies. Their eggs are found in the soil -- thanks to the feces of infected dogs -- where they can survive for years. Puppies can also get the eggs through their mother's milk or even passed through the placenta while still in utero. Adults may carry them without any symptoms. Infected puppies however, may vomit, have diarrhea and lose weight. Sometimes they have a pot belly if there's a large infestation, fail to thrive or have a dull coat.
Roundworms have a strange life cycle. After a dog swallows the eggs, the eggs hatch into larvae. The larvae ride through the bloodstream to the lungs and from there up the windpipe, where they're swallowed again, return to the intestine, and finally become mature adult worms. These adult worms can be seen sometimes in the stool as long wriggling spaghetti strands. As with other types of worms, treatment consists of a deworming pill that kills the adults. Regular fecal exams by your vet should detect them. Again, practicing good dog sanitation is the best way to prevent an infestation.
Hookworms are similar to roundworms in a lot of ways: they usually affect puppies (although adult dogs can have them, too), and they can be passed in the mother's milk. Hookworm larvae, however can even burrow through the skin. And once in the dog's small intestine, they hook onto the intestinal wall, absorbing tissue and blood. One of the classic signs of hookworm infestation is dark, tarry, or bloody stool. In serious cases of hookworm disease, dogs suffer severe anemia and can die. Hookworms can also cause skin disease and infections in humans.
Like most other intestinal worms, hookworms are diagnosed by examining a stool sample under a microscope. If your vet finds hookworm eggs, he or she will probably prescribe medication to kill the adult worms. Typically this is one of the same deworming pills that kill other worms such as roundworms. The best prevention for hookworm is -- once again -- being diligent in picking up after your dog. The longer an infected dog's stool sits, the more likely it is that any hookworm eggs will hatch out into larvae and find their way under your dog's skin.
Worms are some of the nastiest parasites that can infect your dog. The good news is that they're all easily preventable if you follow a few simple rules: be careful about what your dog consumes, clean up after him well, take him in for regular exams, and keep him on medications provided by your vet to prevent the worms (including their hosts, such as fleas) from getting to him in the first place. Follow these and hopefully your dog will remain worm-free for life.
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