What is Giardia?

Giardia is sometimes confused with “worms” because they invade the gastrointestinal tract and can cause diarrhea. Giardia is a one-celled parasitic species classified as a protozoa.

Most dogs that are infected with Giardia do not have diarrhea or any other signs of illness. When the eggs (cysts) are found in the stool of a dog without diarrhea, they are generally considered a transient, insignificant finding. However, in puppies and debilitated adult dogs, they may cause severe, watery diarrhea that may be fatal.

How did my dog get Giardia?

A dog becomes infected with Giardia when it swallows the cyst stage of the parasite. Once inside the dog’s intestine, the cyst goes through several stages of maturation. Eventually, the dog passes infective cysts in the stool. These cysts lie in the environment and can infect other dogs. Giardia may also be transmitted through drinking infected water.

How is giardiasis diagnosed?

Giardiasis or infection with Giardia spp. is diagnosed by performing a microscopic examination of a stool sample. The cysts are quite small and usually require a special floatation medium for detection, so they are not normally found on routine fecal examinations. Occasionally, the parasites may be seen on a direct smear of the feces. Tests are available for detection of antigens (cell proteins) of Giardia in the blood or feces. These tests are more accurate than the stool exam, but it may require several days to get a result from the laboratory.

How is giardiasis treated?

The typical drug used to kill Giardia is metronidazole, an antibiotic. It is normally given for five to seven days to treat giardiasis. Other drugs are also used if diarrhea and dehydration occur. If metronidazole is not effective, other medications may be recommended.

Can humans become infected with Giardia?

Giardia can cause diarrhea in humans. If your dog is diagnosed with giardiasis, environmental disinfection is important. The use of diluted chlorine bleach at 1:32 or 1:16 dilutions (one cup in a gallon of water or 500 ml in 4 liters of water) is effective in killing the cysts. Giardiacysts are very susceptible to drying. We recommend thoroughly cleaning the pet’s living and sleeping areas and then allowing the areas to dry out for several days before reintroducing pets.

What is coccidiosis?

Coccidiosis is an intestinal tract infection caused by one-celled organisms (protozoa) called coccidia. Coccidia are sub-classified into a number of genera, and each genus has a number of species. At least six different genera of coccidia can infect dogs. These microscopic parasites spend part of their life cycle in the lining cells of the intestine. Most infections are not associated with any detectable clinical signs. These infections are called sub-clinical infections. Most clinical infections in dogs are caused by the species Isospora canis. Cryptosporidium parvum is another coccidian parasite that may cause diarrhea in some puppies.

How did my dog become infected with coccidia?

Oocysts (immature coccidia) are passed in the feces of an infected dog. These oocysts are very resistant to environmental conditions and can survive for some time on the ground. Under the right conditions of temperature and humidity these oocysts “sporulate”. If the sporulated oocysts are ingested by a susceptible dog they will release “sporozoites” that invade the intestinal lining cells and set up a cycle of infection in neighboring cells. Dogs may also be indirectly infected by eating a mouse that is infected with coccidia.

What kinds of problems are caused by coccidiosis?

Most dogs that are infected with coccidia do not have diarrhea or other clinical signs. When the coccidial oocysts are found in the stool of a dog without diarrhea, they are generally considered a transient, insignificant finding. However, in puppies and debilitated adult dogs, coccidiosis may cause severe, watery diarrhea, dehydration, abdominal distress, and vomiting. In severe cases, death may occur.

How is coccidiosis diagnosed?

Coccidiosis is diagnosed by performing a microscopic examination of a stool sample. Since the oocysts are much smaller than the eggs of intestinal worms, a careful fecal evaluation must be made. Infection with some of the less common coccidial parasites is diagnosed with a blood test.

How is the coccidial infection treated?

The most common drug used to eliminate coccidia is a sulfa-type antibiotic. It is usually given for ten to fourteen days. In severe infections, it may be necessary to repeat the treatment. Other drugs are also used if diarrhea and dehydration occur. If the sulfa-type drug is not effective, other treatments are available. Re-infection of dogs is common so environmental disinfection is important. The use of diluted chlorine bleach [one cup (250 ml) of bleach mixed in one gallon (3.8 L) of water] is effective if the surfaces and premises can be safely treated with it.

Are the coccidial parasites of my dog infectious to humans?

The most common coccidia found in dogs do not have any affect on humans. However, less common types of coccidia are potentially infectious to humans. One parasite, called Cryptosporidium, may be carried by dogs or cats and may be transmitted to people. This parasite has also been found in the public water supply of some major cites. It poses a health risk for immuno-suppressed humans such as AIDS patients, those taking immune suppressing drugs, cancer patients, or the elderly.

Good hygiene and proper disposal of dog feces are important in minimizing risk of transmission of all canine parasites to humans, or to other animals.

What are hookworms?

Hookworms (Ancylostoma caninum, Ancylostoma braziliense) are parasites that get their name from the hook-like mouthparts they use to attach to the intestinal wall. They are only about 1/8″ (3 mm) long and so small that it is very difficult to see them with the naked eye. Despite their small size, they ingest large amounts of blood from the tiny vessels in the intestinal wall. A large number of hookworms can cause anemia. This problem is most common in puppies, but can occur in adult dogs.

How did my dog get hookworms?

Dogs may become infected with hookworms by four routes:

  • Orally
  • Through the skin
  • Through the mother’s placenta before birth
  • Through the mother’s milk

A dog may become infected when it swallows hookworm larvae. The larvae may also penetrate the skin and migrate to the intestine where they mature and complete its life cycle. If a pregnant dog has hookworms, the pregnancy may reactivate larvae. These larvae will enter the female’s bloodstream and infect the puppies in the womb. Finally, puppies may be infected through the mother’s milk. This is considered to be an important route of infection for puppies.

What kinds of problems do hookworms cause?

The most significant problems appear related to intestinal distress and anemia. Blood loss results from the parasites ingesting blood from intestinal capillaries. Pale gums, diarrhea, or weakness are common signs of anemia. Some dogs experience significant weight loss, bloody diarrhea, or failure to grow properly with hookworm infection.

Skin irritation and itching, especially of the paws, can be signs of a heavily infested environment. The larvae burrow into the skin and cause itching and discomfort.

How is hookworm infection diagnosed?

Hookworms are diagnosed with a microscopic examination of a stool sample. Since there are many eggs produced daily, they are easily detected. One adult female hookworm may produce as many as 20,000 eggs a day!

In puppies, large numbers of worms usually must be present before eggs are shed into the stool. For this reason, fecal examination may be less reliable in very young puppies than in adult dogs

How are the hookworms treated?

There are several effective drugs to eliminate hookworms. They are given by injection or orally and have few, if any, side-effects. However, these drugs only kill the adult hookworms. Therefore, it is necessary to treat again in about 2-4 weeks to kill any newly formed adult worms that were larvae at the time of the first treatment.

A blood transfusion may be necessary in dogs with severe anemia.

Since the dog’s environment can be infested with hookworm eggs and larvae, it may be necessary to treat with chemicals to remove them from your yard. We can offer recommendations for grass-friendly products.

Are canine hookworms infectious to people?

Adult hookworms do not infect humans; however, the larvae can burrow into human skin. This causes itching, commonly called “ground itch”, but the worms do not mature into adults. Direct contact of human skin to moist, hookworm infested soil is required. Fortunately, this does not occur often if normal hygiene practices are observed.

In rare instances, the canine hookworm will penetrate into deeper tissues and partially mature in the human intestine. A few reports of hookworm enterocolitis (small and large intestinal inflammation) have occurred in the recent past.

What can be done to control hookworm infection in dogs and to prevent human infection?

All pups should be dewormed with a veterinary-approved product at two to three weeks of age.

Prompt deworming should be given when parasites are detected; periodic deworming may be appropriate for pets at high risk for infection.

Prompt disposal of dog feces should occur, especially in yards, playgrounds, and public parks.

Strict hygiene is important, especially for children. Do not allow children to play in potentially contaminated environments. Frequent hand washing and bathing are essential in preventing human infections

Nursing females should be dewormed with their pups. Nursing may reactivate hookworm infection in the female.

Most heartworm prevention products contain a drug that will prevent hookworm infections. However, these products will not kill the adult hookworms, so dogs must be treated for adult hookworms.

What are roundworms?

RoundwormRoundworms (nematodes or Ascarids) are intestinal parasites that live freely in the intestine, feeding off of partially digested intestinal contents. Their name is derived from their tubular or “round” shape.

Toxocara canis and Toxascaris leonina are two important species of roundworms in dogs. Toxocara canis causes more significant disease and also may be transmitted to humans.

How did my dog get roundworms?

Microscopic eggs are passed from infected dogs in the feces. These are ingested by sniffing or licking infected feces. They are also spread by other animals such as rodents and birds. In these animals, the roundworms are merely transported. They do not mature into adults but if this paratenic host is eaten by a dog, completion of the life cycle will occur and the dog can become infected

In the dog, the roundworm undergoes a complicated life cycle before mature roundworms are found in the bowel. This involves several stages and also migration through various tissues. Roundworm larvae (immature worms) can encyst in the host’s tissues. This is important in the female dog because these encysted larvae will start to develop during pregnancy and ultimately cross the placenta into an unborn puppy. Thus puppies can be born with roundworms and can pass fertile eggs from adult worms in their stools by the time they are approximately eleven days old. Roundworm larvae may also enter the mother’s mammary glands and be transmitted through the milk.

Are roundworms a threat to my dog?

Roundworms are most threatening to puppies. The most common consequence of roundworms is growth reduction. Since roundworms feed off of partially digested food, they rob the growing puppy of vital nutrients. These puppies often have a characteristic “pot-belly” that is due to the growing roundworms inside the puppy’s abdomen.   The life cycle of Toxocara canis is more complicated than that of other nematode worms found in dogs. Roundworm larvae swallowed by adult dogs usually encyst in the dog’s tissues. Few roundworms will mature in the bowel. Consequently few eggs are passed in the stool leading to difficulty in definitive diagnosis and treatment.

How are roundworms diagnosed?

In puppies we consider clinical signs such as stunted growth, potbelly, and recurrent diarrhea as a good indication of roundworm infection. Definitive diagnosis is made by microscopic examination of the dog’s feces.

Is it true that children can get roundworm infections?

If the infected eggs of Toxocara canis are swallowed by people, the larvae can invade the tissues and become encysted in various organs. Humans act like any other paratenic host. If a large number of infected eggs are ingested, clinical disease may become apparent. This is particularly important if children are infected with roundworms.

Very rarely, liver problems may result from roundworm larval migration (visceral larval migrans). Even less commonly, the larvae can migrate into the eye and cause blindness (ocular larval migrans).

How are roundworms treated?

Treatment is simple and effective. There are many safe and effective preparations available to kill roundworms in the intestine. In addition, many heartworm preventives are also effective against intestinal roundworms and help prevent future infections. Unfortunately, the majority of preparations available today kill only the adult worms and do not affect migrating or encysting larvae. It is therefore important that repeated treatments are administered. Your veterinarian will advise you on the best treatment and prevention plan for your pet.

What about roundworm eggs shed in the environment?

Initially the eggs are not infective. After a period, which may vary from weeks to months, the eggs develop into infective larvae. Under ideal conditions, this takes approximately four weeks. These infective larvae can remain viable in the environment for a considerable time and are particularly resistant to changes in temperature and humidity. The best environmental treatment is prevention. Remove your dog’s feces as soon as possible to prevent the spread and transmission of roundworms. What is the most effective strategy I can use to control infection in my dogs, protect my family and reduce contamination of the environment?

Deworm pregnant dogs in late pregnancy, after the 42nd day or after six weeks of pregnancy. This will help reduce potential contamination of the environment for newborn puppies.

Puppies should be dewormed, starting at about two weeks of age and repeated regularly. Your veterinarian will design the most appropriate deworming schedule for your pets.

Adult dogs are susceptible to re-infection with roundworms throughout their lives. Routine deworming and prevention is important.

  • 1. Rodent control is important since rodents can serve as a source of infection.

Dogs should be restrained from defecating in children’s play areas and there should be prompt disposal of all dog feces, especially in gardens, playgrounds and public parks.

Practice strict hygiene particularly with children. Do not allow them to play in potentially contaminated environments.

What are whipworms?

Whipworms in DogsWhipworms are intestinal parasites which are about 1/4 inch (6 mm) long. They live in the cecum and colon of dogs where they cause severe irritation to the lining of those organs. This results in watery, bloody diarrhea, weight loss, and general debilitation. They are one of the most pathogenic worms found in dogs.

How did my dog get whipworms?

Whipworms pass microscopic eggs in the stool. The eggs are very resistant to drying and heat, so they can remain viable in the dog’s environment for years. They mature and are able to reinfect the dog in 10-60 days. The eggs are swallowed and return to the lower intestinal tract to complete the life cycle.

How is whipworm infection diagnosed?

Whipworms are diagnosed by finding eggs with a microscopic examination of the stool. However, multiple stool samples are often required because these parasites pass small numbers of eggs on an irregular basis. Any dog with chronic diarrhea can be reasonably suspected to have whipworms, regardless of several negative stool examinations. It is an accepted practice to treat chronic diarrhea by administering a whipworm dewormer. Response to treatment is an indication that whipworms were present but could not be detected on fecal examination.

How are whipworms treated?

There are several drugs that are very effective against whipworms. Two treatments are needed at a three to four week interval, but because reinfection is such a problem, it is advisable to treat again every three to four months or to put the dog on a heartworm prevention product that contains an ingredient that prevents infection with whipworms. Whipworms are not nearly as common today because of widespread use of these heartworm prevention products.

Can I get whipworms from my dog?

No. Whipworms are not infectious to people. They are exclusive parasites of the dog.

What are tapeworms?

TapewormsTapeworms are flattened intestinal worms that are made up of many small segments, each about ¼ – ½ inch (3-5 mm) long. Unlike roundworms that live freely in the intestinal tract, tapeworms attach to the wall of the small intestine by hook-like mouthparts.

The most common tapeworm of dogs and cats is Dipylidium caninum. The adult worms may reach up to 8 inches (20 cm) in length. The individual segments are developed from the head end and gradually mature, finally being shed at the opposite end, either singly or in short chains. These segments are passed in the feces when the dog defecates. They are about 1/8” (3 mm) long and look like grains of rice or cucumber seeds. Occasionally they can be seen moving on the hairs around the anus or on freshly passed feces. As the tapeworm segment dries, it becomes a golden color and the fertilized eggs are released into the environment.

Unlike roundworms, dogs cannot become infected by eating fertilized tapeworm eggs. Tapeworms must first pass through an intermediate host, a flea, before they can infect a dog or cat.

How do dogs get tapeworms?

When the infected eggs are released into the environment, they have to be swallowed by immature flea larvae  in the environment. Once inside the larval stage of the flea, the tapeworm egg continues to develops into an infective tapeworm as the flea matures into an adult flea. During grooming or in response to a flea’s bite, the dog can ingest the flea carrying the infective tapeworm and the life cycle is completed.

Are tapeworms dangerous for my dog?

Tapeworms do not normally cause serious health problems in dogs. Occasionally dogs will drag their bottoms on the ground scooting in order to allay this irritation but this behavior can be for other reasons such as impacted anal sacs.

In puppies, heavy tapeworm infestation can be more serious. Lack of growth, anemia and intestinal blockage can occur. Occasionally, the head of the tapeworm or scolex detaches from the intestinal wall. The worm can then be passed either in the feces or vomited.

How is diagnosis made?

Clinical diagnosis is usually made by observing the white mobile tapeworm segments in the feces or crawling around the anus. They often look like grains of rice.

Tapeworm segments are only passed intermittently and therefore are often not diagnosed on routine fecal examination. If you find any segments, white or golden color, bring these to us for a definitive diagnosis.

What is the treatment?

With today’s drugs, treatment is safe, simple and effective. The parasiticide may be given either in the form of tablets or by injection. It causes the parasite to dissolve in the intestines so you normally will not see tapeworms passed in the stool.

These drugs are very safe and should not cause vomiting or diarrhea or other adverse side effects.

Is there anything else I should do?

Flea control is critical in the management and prevention of tapeworm infection. Flea control involves treatment of your dog and the environment. Your veterinarian can recommend safe and effective flea control for your pet. If your dog lives in a flea-infested environment, re-infection

with tapeworms may occur in as little as two weeks. Since tapeworm medication is so effective, recurrent tapeworm infections are almost always due to re-infection from fleas and not failure of the product.

Can I get tapeworms from my dog?

Contracting tapeworms from your dog is not common or likely. Dipylidium caninum, the most common tapeworm of the dog, depends on the flea as the intermediate host. A person must swallow an infected flea to become infected. A few cases of tapeworm infection have been reported in children. Vigorous flea control  will also eliminate any risk of children in the environment becoming infected.

Although Dipylidium species are the most common tapeworms in dogs, other Cestodes are also important in certain areas.

Taenia species – These are tapeworms are acquired by eating prey or waste containing the infective larval stage. These are much larger tapeworms, often up to one yard (one meter) in length. Intermediate hosts include rodents, rabbits, hares and sheep. The intermediate stages develop hyadatid cysts in various organs. We have excellent treatment for Taenia infections in dogs.

Echinococcus species – By contrast, these are very small tapeworms. They consist of only three or four segments and are usually less than 3/8” (1 cm) in length. Intermediate hosts can be sheep, horses and occasionally man. Infection is by ingesting eggs that have originated from the feces of dogs or foxes harboring the adult tapeworm. Fortunately de-worming preparations, particularly those containing praziquantel are effective for eliminating the Cestode from the dog.

Control measures to prevent tapeworm infection from Cestodes involve avoidance of uncooked or partially cooked meat or waste.