Hook worms are intestinal parasites in dogs, cats, fox.
(Some can also affect humans by migrating through the skin)
(Refer to human animal infestation of hookworms at the end of this article)
There are three species of hookworms that affect dogs.
Ancylostoma caninum    (Canine hook worm)    (Dog, fox, possibly humans)(intestine)
Ancylostoma braziliense   (Canine and feline hook worm)   (Dog, cat, fox, human) (skin)
Uncinaria stenocephala     (Northern canine hook worm)   (Dog, cat, fox)

Hook worms are small, thin worms that are usually less than an inch long. The appearance of the mouth appearance
varies by species, but all hookworms have hook-like teeth or plates for them to attach to the intestinal wall. Unlike
roundworms, which just float around and steal nutrients from the dog's intestinal tract, hookworms attach to the
intestinal wall and feed on blood and tissues. They can move to other spots, leaving ulcers where they have fed.
The severity of symptoms varies between the hookworm species and most infections are considered not life
threatening, but one species of hookworm ,
Ancylostoma Caninum can cause fatal blood loss in puppies.

The Hook worm Life Cycle

Hook worm eggs are passed in the feces, and under warm, moist conditions hatch into larvae after several days.
These larvae have several ways they can infect dogs:
They can be ingested when dogs lick the ground or groom themselves.
They can migrate through the skin, usually through the belly or paws.
Your dog or cat ingests a rodent.
Larvae present in the mom’s milk can also infect puppies

Once the larvae get into a dog, they may develop into adults in the intestines or may migrate through the soft tissues
to the lungs, from where they are coughed up and swallowed, and then finally develop in the intestines. In older dogs,
migrating hookworm larvae commonly enter a dormant state within body tissues, and reanimate again later.

In pregnant females the larvae commonly become mobilized during pregnancy, where they can either go to the
mammary glands (for some kinds of hookworms), or develop into adults in the mom's intestines, producing eggs which
act as a source for infection of puppies. Hookworm infections are common in puppies!

Signs and Symptoms of Hook worms

Hook worms can produce the following symptoms,
though the signs only appear with heavy infections:
Failure to gain weight, or weight loss
Loss of appetite
Anemia (pale gums, weakness) and can be a cause of death in puppies
Bloody or tarry stools
Sometimes coughing can occur due to the larval migration through the lungs
(Very heavy infections)
Skin irritation, most often on the feet between the toes, due to larvae introduction
The severity of the infestation depends on the species of hookworm, as well as the number of worms and the age and
health of the dog.

Diagnosis of Hook worms

The eggs of hookworms are detected under the microscope in a vet or tech check of a stool sample
(The process is called fecal flotation).
It takes a while for infected puppies to shed eggs, so do a preventative de-worming of puppies.

Treating Hook worms

Treatment is the same, regardless of the species. There are a number of medications/insecticides that can be used to
treat hookworms. Treatments will only affect hookworms in the intestines, not migrating larvae, so treatment should be
repeated to deal with larvae as they mature (2 week intervals). The number of treatments necessary will depend on
the dog and the situation

If you have a pregnant dog
you think maybe infected,
consult a vet for advice.
Never use an over the counter
de-wormer on a pregnant dog.
If you have a pregnant dog, consult your vet for a de-worming protocol for both the mom and or pups.
Once de-wormed, many of the monthly medications designed for external parasite control contain medication that will
prevent roundworm infections. If your dog is not on one of these preventative medications, a regular de-worming
protocol should be established to keep roundworms at bay.


Keep pet wastes picked up, prevent your dog from eating rodents, carcasses, or other animals. Keep your put from
ingesting fecal matter. Do not take your dog in areas where other dogs or animals are allowed to roam or play, if at all
possible.(This suggestion alone prevents a lot more then just internal parasite infestations.)Have your animal on a
preventive medication. (A veterinarian dispenses these) Have your dog on a regular de worming schedule especially in
high infestation areas (Southern climates) Become aware of the types of internal parasites your dog may be exposed
to and practice responsible ownership by educating yourself in order to help your dog live a healthy and parasite free

People and Hook worms

The larvae of hook worms can infect people also.
This happens when the eggs are ingested,
the larvae usually don't develop into adult Hookworms,
but the larvae borrowing through the skin
can cause irritation and inflammation,
though most cases are not serious. Migration of  the larvae through human skin is called "cutaneous larva migrans."
There have been a few cases reported where one kind of hookworm took up residence in the intestines of human
animals, as well. Proper treatment and prevention of hookworm infections is important to prevent these human health
concerns, as is good hygiene. Keeping pet waste picked up, preventing children or people from going into areas
where the dog has used as a bathroom. Hygiene for both dog and human is essential.

John A Sampson I
K9 Training
00 + 1 + 989-662-6230 International
canines and hook worms
Dog Hook Worms
Canine Hookworm
How a hookworm attaches itself to the intestine
Hookworm mouth
Male and female hookworm
Infested gut with hookworm
Human animals with hookworm infestation
Hook worm infestation of human animal
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