Critters You Did NOT Want to Take Home

Anne K. G. Bazilwich, DVM
Member of the Vermont Veterinary Medical Association, www.vtvets.org.

Nobody wants their pet harboring fleas, worms, lice, or other parasites; the mere thought is sickening. But, if parasites are a problem, how do you recognize that your pet has them? And, how do you prevent those offensive critters from making their home on your adorable dog or cat?

Everyone knows that there are many different types of parasites out there. There are also parasites that prefer to live on a certain type of animal. The scope of this article will address dogs and cats; our large and exotic animal friends will be discussed later. Furthermore, it may be interesting to note that ringworm is not a parasite, it is a fungus.

If you see a flea on your pet, you would obviously know that he/she has fleas. However, you may not know that your animal has heartworms or intestinal parasites. They can live in your pet for a good deal of time before showing signs of their presence. It may even be difficult to determine if your pet has mites or ticks. Certainly, if you notice anything abnormal going on with your animal including, but not restricted to, coughing, vomiting, diarrhea, or skin problems, please consult your veterinarian; parasites may or may not be an issue.

There are tests available to help identify parasites on our pets. Some require blood testing, others need a fecal, or stool, exam, and a few can be found by looking at scrapes from the skin under a microscope.
Fortunately, there are many new products available to help prevent a parasite burden on your pet. It is best to follow the advice of your veterinarian in deciding what parasites need to be prevented or treated and what product is best for your individual pet.

Let's discuss some of the more common parasites that affect our pets in Vermont.

Fleas: Usually, dogs and cats display itchiness and sometimes hair loss and red, inflamed skin if they have fleas. I have noticed that some people prefer to prevent fleas, especially in animals that are allergic to them, while others prefer to wait and treat a problem if it arises. Fleas spend the majority of their life cycle off of the host. The eggs, larvae, and pupae are generally found in the environment. The adult flea will take a blood meal from the animal and then go back into the surroundings. Therefore, noticing one or two fleas on your pet means that there are thousands more where your pet lives. Although adult fleas cannot withstand cold temperatures, their eggs are hardy and can survive through our harsh winters. If there is a population of fleas in your house, you undoubtedly keep your dwelling warm enough to ensure their survival. If you wish to prevent fleas from coming into your home, keep your pets that go outside on a veterinarian recommended flea preventative from spring through the second frost.
Heartworm: Unfortunately, since clinical signs of a heartworm infection are usually evident in the later stages of this fatal disease, it is crucial that this parasite be prevented. Most veterinarians advocate annual or bi-annual blood testing to screen for heartworm disease in your dog, depending on whether heartworm preventative is used year round or seasonally. The prescription heartworm preventatives used today are safe and extremely effective, and some integrate an intestinal dewormer as well (see below).
The larval stage of the heartworm is transmitted to animals through a mosquito bite. The larvae eventually develop into adult heartworms that live in the heart or a major blood vessel. Heartworm disease can be treated, but it is both painful and risky. Cats can also acquire heartworm disease and there are preventatives available for them.
Intestinal Worms: Dogs and cats may show no clinical signs at all with a population of intestinal worms, or they may display weight loss, vomiting, or diarrhea. Intestinal parasites can be fatal, especially in young or compromised animals. Also, it is important to understand that some intestinal parasites can be passed to humans, particularly children; therefore, adequate parasite control is crucial. The common intestinal worms include roundworms, hookworms, whipworms, and tapeworms. Some of the heartworm preventatives will also keep your animal free of intestinal worms, though additional medicine is usually required to control tapeworms. Your veterinarian can develop strategic deworming protocols for your pet. It varies depending on exposure, such as length of time out of doors and whether or not your pet hunts. There are other intestinal parasites, such as protozoa, that are managed differently.
Ticks: Ticks rarely cause clinical signs, unless they have transmitted a disease. Any tick can give an animal Lyme Disease, Rocky Mountain Spotted Fever, and Ehrlichiosis, to name a few. Ticks can also attach to humans. Seed ticks are the larval stage and are extremely small and difficult to see, but can also attach to animals and transmit disease. There are products available to help prevent and kill ticks. If a tick is attached to your pet, it is very important that it be removed properly so the mouthparts are not left behind. Use a special tool designed to remove ticks or tweezers to pull the tick out. Never use alcohol, fire, or other methods to try and detach the tick as this will stimulate the tick to regurgitate into the animal and possibly transmit disease.
Mites: Itchiness, hair loss, and skin problems are associated with mites. Ear mites usually cause a dark discharge deep in the ear canal. Some mites are contagious, including sarcoptic mites (that cause scabies or sarcoptic mange) and ear mites, and others appear when the animal is immunocompromised, such as the demodex mite. The contagious mites may be passed on to humans. There are drugs available to prevent or treat the contagious mites. The demodex mite needs to be controlled differently since there is an underlying problem or genetic predisposition that causes this mite to get out of hand.