What are whipworms?

Whipworms are intestinal parasites that are about 1/4 inch (6 mm) long. They live in the cecum and colon (large intestine) of dogs where they cause severe irritation to the lining of those organs. Whipworm infection results in watery, bloody diarrhea, weight loss, and general debilitation.


They are one of the most pathogenic worms found in dogs.

whipworm infections 1 2009 Whipworms

How do dogs get whipworms?

Whipworms pass microscopic eggs in the stool. The eggs are very resistant to drying and heat, so they can remain viable (alive) in the  environment for up to 5 years. Once laid, they embryonate (mature to an infective stage) in the environment and are able to re-infect the dog in 10-60 days. The   embryonated eggs are swallowed and hatch and mature to adults in the lower intestinal tract, completing their life cycle (see illustration).

How are whipworms  diagnosed?

“Parasites pass small numbers of eggs on an irregular basis, so some samples may be falsely negative.”

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, so some samples may be falsely negative. In addition, it takes approximately 11-12 weeks after hatching for a female adult to begin to lay eggs.  Any dog with chronic large bowel diarrhea should be suspected to have whipworms, even if the stool sample was negative.
Thus, 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.

whipworm infections 2 2009 Whipworms

How are whipworms treated?

There are several drugs that are very effective against whipworms. At least two treatments are needed, spaced at a three to four week interval. The most frustrating aspect of whipworm infections is the high rate of re-infection because the eggs are extremely hardy in the environment.  Therefore, if a dog is diagnosed with a whipworm infection, it is advisable to treat again every three to four months. The other option, which is much simpler, is to use a heartworm preventative that contains a whipworm medication. Whipworms are not nearly as common today because of widespread use of these modern heartworm prevention products.

Can I get whipworms from my dog?

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

This client information sheet is based on material written by: Ernest Ward, DVM
© Copyright 2009 Lifelearn Inc. Used and/or modified with permission under license.

What are Coccidia?


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.”

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. The species Isospora canis  causes most clinical infections in dogs. Cryptosporidium parvum is another coccidian parasite that may cause diarrhea in some puppies.


canine coccidiosis   2009 Coccidia

How did my dog become infected with coccidia?

An infected dog passes oocysts (immature coccidia) in the feces. These oocysts are very resistant to a wide variety of environmental conditions and can survive for some time on the ground. Under the right conditions of temperature and humidity, these oocysts “sporulate” or become infective. If a susceptible dog ingests the sporulated oocysts, the oocysts 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.

“In puppies and debilitated adult dogs, coccidiosis may cause severe, watery diarrhea, dehydration, abdominal distress, and vomiting.”

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 may be required if diarrhea and dehydration occur. If the sulfa-type drug is not effective, other treatments are available. Re-infection of susceptible 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?coccidiosis Coccidia

“The most common coccidia found in dogs do not have any affect on 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 immunosuppressed humans such as AIDS patients, those taking immune suppressing drugs, cancer patients, or the

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.

This client information sheet is based on material written by: Ernest Ward, DVM© Copyright 2009 Lifelearn Inc. Used and/or modified with permission under license.

Toxoplasmosis in Cats


You may have heard that Toxoplasmosis is a disease that is dangerous for pregnant women and immuno-compromised individuals. Beyond this basic information, many myths abound. Does it mean you need to give up your feline friend? Do you need to get tested? Is it safe to clean the litter box? A little knowledge can go along way towards addressing your concerns and fears.

What It Is
Toxoplasma gondii is a tiny protozoan that can infect any mammal. Cats are considered the main host, since they are the only animal in which the organism can complete its entire life cycle.

How People Get It
Although cats are frequently blamed as the primary source of infection, this is a misconception. More commonly, people are exposed when they eat undercooked meat. Scientific studies show that the organism can be found in up to 20% of meat samples tested.

Cats can be a source of infection, but it is less common. Cats get the organism by hunting outdoors and eating other infected animals. When a cat first becomes infected, it goes through a brief period in which it can pass the organism in its feces. This only lasts for a few weeks. When the organism is passed in the cats feces, it is not immediately infectious to humans; it must sit for several days first. If the litter box is cleaned out daily, it is quite unlikely for cat owners to directly contract the organism from their own cats.

cat face

Its more likely for a person to be infected if they garden in soil in which cats have defecated. The organism can survive in the soil for years. The organism still must be swallowed. This could happen if a person put his hands in his mouth without washing or ate unwashed vegetables that were grown in the contaminated soil.

The final method of infection is congenital, when a pregnant woman with an active case of Toxoplasmosis passes the organism to her fetus while it is in the uterus. Women are only likely to be infectious to their fetuses when they initially become infected.

Toxoplasmosis in People
In the United States, only 1-2% of people show evidence of exposure to Toxoplasma. The organism does not cause any symptoms at all in most people. Immunosuppressed individuals are much more likely to become infected by Toxoplasma and may suffer serious consequences such as encephalitis. Infection of a fetus with Toxoplasma can result in miscarriage, congenital brain disorders, or congenital eye disorders.

Symptoms in Cats
Symptoms in cats are rare, but are more likely to occur in young cats with weak immune systems and in cats that are immunosuppressed as a result of infection with Feline Leukemia Virus (FeLV) or Feline Immunodeciency Virus (FIV). Symptoms can include weight loss, pneumonia, and eye disorders.


Whether it is necessary to be tested for Toxoplasmosis is a decision that you should make with your physician. There are blood tests available that can detect if you have a current, active infection or if you have been exposed in the past, but do not have a current infection.

Preventing Toxoplasmosis
To minimize the chance of exposure to Toxoplasma, always cook meat thoroughly. Wash your hands, cutting boards, and utensils after working with raw meat. Wear gloves when gardening outdoors. Clean litter pans every day. The need for pregnant women and immunocompromised people to avoid cleaning litter boxes is controversial. Women who test positive for exposure prior to pregnancy are unlikely to pass the disease to their fetus, so it is probably safe for them to clean the litter box. Women who have not been previously exposed and immunocompromised individuals should probably avoid cleaning litter boxes if possible, especially if their cats hunt.