Demodex – Mange in Dogs

Mange is a parasitic skin disease caused by microscopic mites. Two different mange mites cause skin disease in dogs. One lives just under the surface of the skin, while the other resides deep in the hair follicles. Although both mites share similar characteristics, there are also important differences. It is important not to confuse the two types of mange because they have different causes, treatments, and prognoses.

What causes demodectic mange?

Demodectic mange, sometimes just called “demodex” or “red mange”, is the most common form of mange in dogs. It is caused by the Demodex canis, a parasite that lives in the hair follicles of dogs. Under the microscope, this mite is shaped like a cigar with eight legs.
demodectic mange 2009 Demodex Mange

All normal dogs (and many humans) have a few of these mites on their skin. As long as the body’s immune system is functioning properly, these mites live in harmony with their host and  cause no harm.

Demodectic mange most often occurs when a dog has an immature immune or a defective immune system which will allow the number of skin mites to grow rapidly. Some breeds of dogs are more prone to the disease and there may be a genetic factor for the prevalence of Demodectic mange. Because of this, the disease is found primarily in young dogs less than twelve to eighteen months of age and dogs with severe mange should not be bred. As the dog matures, its immune system also matures. Adult dogs that have the disease usually have defective immune systems. Demodectic mange may occur in older dogs because function of the immune system often declines with age. Dogs who have immune suppression due to illness or certain medications are also candidates for demodectic mange.

Is demodectic mange contagious?

No, demodectic mange is not contagious to other animals or humans. Demodex mites are transmitted to puppies from their mother during the first few days of life. Since the mite is found on virtually all dogs, exposure of a normal dog to one with demodectic mange is not dangerous.
demodectic mange 2009 2 Demodex Mange
Why doesn’t the immune system mature correctly in some dogs?

Development of the immune system is under genetic or hereditary control. Thus, an affected dog often has littermates that are also affected. Owners of littermates should be alerted to watch for the development of the mange in their puppies. Because the disease can be due to a genetic defect of the immune system, affected dogs should not be bred, and the parents of the
affected dog should not be bred again.

What does demodectic mange do to the dog?

Surprisingly, a dog with demodectic mange usually does not itch severely, even though it loses hair in patches. The hair loss usually begins on the face, especially around the eyes. When there are only a few patches of hair loss, the condition is called localized demodectic mange. If the disease spreads to many areas of the skin, it becomes generalized demodectic mange. The mites multiply in the hair follicle which causes the hair to fall out. When the integrity of the skin is broken, then bacteria that normally resides on the skin can penetrate the broken skin and cause a secondary skin infection or a “pyoderma” . Because the immune system in these dogs in often defective, the skin infection can sometimes become severe.

How is demodectic mange diagnosed?

Your veterinarian will take deep skin scrapings and try to squeeze the mites out of the hair follicles and examine them under the microscope to diagnose this disease. The finding of larger than normal numbers of Demodex mites in skin scrapings confirms the diagnosis. Occasionally, the disease will be diagnosed by means of a
skin biopsy in dogs that have chronic skin infections that have not responded appropriately to treatment.
demodex
What is the treatment for Demodectic mange?

The localized form is usually treated with topical medication. The generalized form requires more aggressive treatment using special follicular flushing medicated shampoos and dips, along with oral medication. Shampooing with special
cleansing shampoos containing benzoyl peroxide helps to flush out and open the hair follicles prior to dipping. In some cases, especially dogs with generalized demodectic mange, secondary skin infections complicate the condition, requiring antibiotic therapy. Dogs with skin infections often have very red, inflamed skin. This is the source of the
term “red mange.”

Are there any problems with topical treatment?

The dip commonly used for demodectic mange contains the insecticide amitraz. It must be used cautiously because it is a strong insecticide that can cause side effects, both to your dog and to you, if not used properly. Your dog may experience vomiting and sedation for twenty-four to thirty-six hours following each application. Most of these problems are self-limiting and resolve without medical intervention. If your dog reacts in this manner, you should dilute the next dip with 25% more water. Since most dogs develop tolerance to the dip as they are repeated, your dog is less likely to have side effects with each subsequent treatment. After receiving two to three dipping treatments at 2 week intervals, skin scrapings should be repeated and
examined for the presence of live mites or mite eggs. The results of these skin scrapings will determine whether further treatment is needed. Often a minimum of 6 to 8 dips is necessary to control the disease.

Is there a drug that can be given orally for demodectic mange?

Yes, under certain conditions.

Ivermectins are a class of drugs that are approved for prevention of heartworm disease in dogs and cats. Milbemycin oxime, the active ingredient of Interceptor® and Sentinel® heartworm preventives,
may be used to treat demodicosis in certain cases. Certain   ivermectins are used to treat parasites on cattle. In the past, the cattle preparation has been used orally for demodectic mange in some dogs. However, it is a very strong drug that can cause severe side-effects, including death, if it is not administered properly. It is not approved for use in dogs, so we would only consider using it as long as you are  willing to accept liability for adverse effects. Veterinarians do not generally recommend ivermectin usage in collies, Shetland sheepdogs, Australian shepherds, old English sheepdogs, or any other herding breed.

Check with your veterinarian for the recommended medicine to treat your dog.

What is the prognosis for my dog?

Treatment of demodectic mange is generally successful. However, if the immune system is defective, neither the mites nor the infection may respond to treatment. With generalized demodicosis, successful treatment may take a long time and re-occurrences can develop later in life or with stress.

Because the immune system does not mature until twelve to eighteen months of age, a dog with demodectic mange may have relapses until that age. It is important to treat as soon as a relapse occurs to minimize the possibility of developing resistant mange.

 

 

 

 

What are Coccidia?

coccidiosis

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
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.

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.

Hookworms

hookworm teethHookworms are a very common intestinal parasite of dogs. They get their nickname from the hook-like mouth parts (teeth) that they use to anchor themselves to the wall of the intestinal tract.  Once they have attached, they feed on the blood of their host. Hookworms are very small and are difficult to see with the naked eye, but the damage and the amount of blood they consume can be massive. Large numbers of hookworms in young puppies can cause severe anemia from the blood loss and many puppies can die without a blood transfusion.

Dogs can get hookworms many different ways. Young puppies can be infected while still in their mother’s womb directly through the placenta as well as through the milk when nursing. Because of this early infection, puppies should be de-wormed when they are just 2 weeks old and repeated every 2 weeks for the first few months of their lives. Monthly de-worming is recommended as a regular prevention.

 

 

Adult dogs can become infected by walking through contaminated soil where active larvae hatched from eggs deposited in fecal matter can penetrate directly through the pads of their feet. Once the larvae enter the skin, they then migrate through the body until they reach the lungs, at which time they are coughed up and swallowed. While the hookworms are migrating through the body, many can encyst in the muscle and lay dormant for many years. These are the source of hookworms that infect puppies while in the womb. After the hookworms are swallowed, they reach the intestinal tract and latch on to the wall of the intestine and start feeding on blood. The adult worms also mate and lay thousands of eggs that are passed in the feces. The eggs hatch into
larvae in moist warm environments which start the life cycle again. 11. Ancylostoma adults Hookworms

Humans can also become infected if walking barefoot through contaminated areas, however, the hookworms cannot complete their life cycle, but do cause a localized dermatitis where they penetrate the skin and can cause other problems while trying to migrate through the body.
Some people can have allergic reactions to the migrating worms.

Dogs can also be infected by ingesting the larvae, either by cleaning their feet or fur, or when drinking water or licking contaminated surfaces.

 

Because of the prevalence of hookworms in dogs, many veterinarians and the CDC (Centers of Disease Control) recommend routine de-worming with anthelmintics. Several of the newer flea and heartworm preventatives also include ingredients to remove hookworms and other parasites as well. Your puppy should be tested for hookworms as soon as your get him and follow your veterinarians recommendations for maintenance. Breeders should have the mother dog and young puppies dewormed every 2 weeks. Anthelmintics do not affect the dormant hookworms in the muscle.  Studies have shown that these hookworms can release during gestation and infect the puppies for up to seven
consecutive litters.

Signs of hookworm infection can include pale gums, a dark ,tarry stool, diarrhea, weight loss and failure to thrive.  Older dogs can develop diarrhea or dark, tarry stools.

You can limit the amount of hookworms deposited in your yard by cleaning up the fecal material and disposing of it. Fecal waste from dogs should not be used in compost bins, but there are special compost bins to handle the waste.