Intestinal parasites can be a serious threat to the health of your pet. Did you know they also present a health threat to people? A zoonotic disease is a disease of animals that may transmit to man under natural conditions. People infected with intestinal parasites of animals may have symptoms that differ from those of their pets.

Symptoms of infection may have serious consequences and include; stomach ache, skin rashes, pneumonia, blindness and seizures. It is important to know that young children are especially vulnerable. The reasons for the increased likelihood of childhood infection are due to the life cycle of the parasite and the contact risk associated with children.

Intestinal parasites of the phylum nematode, such as hookworms and roundworms have stages of their life cycle were they exist in the environment. It is while in these stages, humans can come in contact with the organism and become infected.

For example, the hookworm larvae lives in the soil can burrow through the skin or are consumed by an animal. As they mature, the larvae migrate to the small intestine where they attach to the intestinal wall. Here they feed, mature and reproduce. Hookworm eggs are dispersed through the feces approximately 14 days after infection. Infections may also be spread from mothers to nursing puppies. After reaching warm, moist soil, infective larvae develop in one to three days. Children can become infected through contact with a contaminated environment, via a fecal-oral route or by larvae penetrating the human skin. Intestinal parasite larvae are found in areas such as parks, playgrounds and yards.

A typical round worm goes through 4 stages before it becomes an adult. The first stage develops into a larva, from an egg that was shed in animal feces. The second stage can be found in the soil or in contaminated feces. The third stage or the infective stage is consumed by the host and develops into an adult in the alimentary tract or intestinal mucosa. Here they reproduce and begin the cycle all over again by producing eggs that are shed in the feces.

Signs of round worm infections in your pet are: diarrhea, malnutrition, respiratory distress, vomiting, loss of appetite, weakness, weight loss, dull- scruffy hair coat, swollen abdomen, and eggs or adults in the feces. Signs of hookworm infection in your pet include: weakness, diarrhea, weight loss, pale gums, and sudden death.

Although there are many other internal parasites that are medically and economically important to man at this point I believe it is important to mention the tapeworm. Tapeworms belong to the class Cestoda, almost all tapeworms require at least two and some require three hosts to complete their life cycle. Tapeworms contain both sexes in the same individual. An adult tapeworm is essentially a chain of independent, progressively maturing reproductive units, one end of which is anchored in the wall of the host's intestine by a holdfast organ. These segments can sometimes be seen crawling near the rear of your pet, where they will drop off, and begin their life cycle. Humans can become infected by ingesting these gravid segments or infected meat that contains tapeworm cysts. Your pets can become infected by several different routes, including consumption of intermediate animal hosts, consumption of tapeworm eggs, or consumption of infected fleas. Tapeworms are difficult to find on routine fecal examination and are most often diagnosed by visually observing the motile tapeworm segments.

Responsible pet owners make sure their pets are adequately protected, from internal parasite infections by routine fecal examinations done by their veterinarian and appropriate treatment and preventative measures.

In the vast majority of cases, the diagnosis of gastrointestinal parasitism involves the processing of fecal samples. A variety of techniques has been developed by which to examine these and in this discussion I will detail some of the more reliable methods.

Sample collection by the owner is the first and possibly the most important step in an accurate fecal exam. It is always best to obtain fresh fecal samples. If this is not possible, the owner should inform the age and source of the sample. It is important to identify the fecal sample with the appropriate animal in multi-pet households, especially with cats that share litter boxes. Many parasitic organisms undergo quite rapid developmental changes soon after they are voided in the feces, and their new forms may become difficult to recognize. Hookworm eggs, for example, hatch very rapidly in warm moist conditions. Motile hookworm larvae can be found in fecal samples as soon as 24 hours. Other types of parasites deteriorate very rapidly after being passed in the stool, so that samples which are not fresh are useless for examination. Therefore, fresh feces from the appropriate patient are imperative for the accurate identification of gastrointestinal parasitism.

Sample handling is also very important; the pet owner is recommended to use disposable latex gloves while collecting the sample. Placing the sample in an airtight container such as a zip lock bag or a small plastic container with a lid is preferred. Approximately 2 grams of fecal material, about one teaspoon is a sufficient amount for examination. If the sample cannot be delivered to the veterinarian immediately the outside of the container should be cleaned and can be placed in the refrigerator for temporary storage. Make sure you wash your hand with soap and water after collection is complete There are four common diagnostic procedures, for fecal examination; direct smears, fecal flotation, microscopic examination and sedimentation.

When performing a direct smear, a small amount of material is collected on the end of a wooden applicator stick and mixed with a drop of water or saline on a microscopic slide, it is then covered with a cover slip, to identify protozoan organisms a small drop of iodine can be place on the smear to highlight the organisms. Limitations to direct smear technique are sample preparation and the small amount of fecal material being examined. Therefore this test should never be used as the sole means of parasite identification, but it is an important complement to the flotation test.

The basis of the fecal flotation test is that parasite ova and cysts can be separated from other similarly sized fecal debris because of differences in density. The eggs, oocysts and larvae are usually less dense than flotation solutions and therefore will rise to the surface of the mixture where they can be collected and examined. Fecal flotation allows one to examine a larger sample of feces and increases the efficacy of the exam. There are a number of flotation solutions available, including sucrose, sodium chloride, magnesium sulfate and zinc sulfate. I prefer, zinc sulfate, but each media has variations in efficacy and convenience. Once the fecal sample is placed into the floatation solution it is allowed to set for approximately thirty to sixty minutes, with a microscopic slide cover slip resting just on top of the liquid. This allows any products of parasitic infections to float to the top and collect on the cover slip. The cover slip is
then placed on a microscope slide and examined using a compound microscope.

Other procedures for identifying parasitic procedures are generally not needed in small animal medicine, but the sedimentation technique can be useful if trematode species infection is suspected. I will just mention that the procedure is available and will not illiterate on the steps necessary to perform the exam.

For the scope of this article we will limit our discussion of antiparasitic drugs to the most common antiprotozoals and the antihemintics that are currently being used in the treatment of intestinal parasitism in small animals.

Metronidazole, commonly known as Flagyl, is an antibacterial and antiprotozoal agent. It has efficacy against anaerobic bacteria. It is also an effective antiprotozoal agent, in treating Giardiasis, and other coccidial infections. Another commonly used anticoccidial agent is sulfadimethoxine(Albon), it is used to treat coccidal diarrhea in dogs and is widely used in breeding facilities. The most popular antihelmintic drugs in use today are the: bendimidazoles such as fenbendazole(Panacur). Fenbendazole is indicated in the treatment of ascarids, hookworms and tapeworms. Some resistance has been reported to this drug and it must be used for three days in a row to remove tapeworm. Epsiparantel(Cestex), is a very safe and effective single oral dose tablet that removes the common tapeworms. Praziquantel is another antihemintic drug of note it has a wide range of efficacy against adult and larval tapeworms and round worms. Ivermectin is a synthetically modified derivative of antiparasitc agents known as avermectins. Ivermectin is effective against all roundworms and is very effective against the heartworm microfilaria, but it has no activity against the adult heartworm, though recent studies may disprove this. It also used in the extralabel treatment of ear mites and other mites and lice. Pyrantel Pamoate,(Strongid,Nemex) is marketed as a ready to use suspension and as tablets for small animals. It is well absorbed after oral administration, it is very effective against all round worms and has some efficacy against tapeworms when used at twice the recommended dose.

In conclusion, control of internal parasitism is an integral part of any preventative health program for your pet. Not only do routine fecal examinations and regular parasite prevention extend the life of your pet, it is also an important part of the health and safety of your family. The Centers for Disease Control and Prevention estimate that there are more than 10,000 cases of human roundworm infection in the U.S. annually. So make sure, you work with your veterinarian to establish the best possible parasite control program possible.