Hookworms

Hookworms

What are Hookworms?

If you look at the picture you will notice that the “business end” of the Hookworm is shaped like a tiny goblet with three sets of teeth. The goblet-shaped mouth is very hard and resists collapse as the worm sucks. The Hookworm grasps onto the inner surface of the small intestine with the teeth and then pierces a blood vessel. An anti-coagulant saliva-like substance is released which prevents the blood from clotting. Each hookworm can suck 0.1cc of blood per day. If they release the wound continues to bleed.Hookworm

How do our pets get Hookworms?

Kittens or puppies may be born with Hookworms! Hookworm larva are tiny enough to migrate through the placental blood supply to the fetal lungs. Soon after birth, the juvenile Hookworms are coughed up and swallowed. They then mature in the small intestine; attach to the intestinal wall and begin sucking blood and laying eggs.

A second source of infection is through the mother’s milk – Hookworm larva can gain entry into the mammary glands and be passed to the puppies or kittens as they nurse. The larva then mature in the intestine to form blood sucking adults.

The third possibility is if the pet should swallow a Hookworm larva found in the environment (like on a blade of grass, a toy, water or food dish). The Hookworm larva mature to adults in the intestine as above. Soon after feeding on blood the Hookworm adults begin laying eggs which pass with the feces. Under favorable conditions (moisture and warmth) the eggs hatch within 12 to 18 hours and a tiny juvenile Hookworm emerges. This larva is encased within a sheath that offers protection against dessication and ensures long life in the environment. The larva reside in moist areas of the soil and overlying vegetation.

The most important mode of transmission is unique! I mentioned above how the eggs pass with the feces and hatch within 12 – 18 hours on moist ground. The newly hatched larva then become free-living organisms which thrive in moist soil or on damp grass awns. Another interesting thing is that the larva can live for many weeks without food.

These free-living larva are able to penetrate the intact skin of dogs or cats passing by or as a pet lies on the ground the heat excites the larva and they go right through the thin skin of the ventral abdomen. Picture this! You take your dog on a walk in a park where Hookworm infested dogs have deficated. As your pet passes through the wet grass an infective juvenile Hookworm brushes onto the paw. The larva easily penetrate the skin and follow a blood vessel to the lungs. From there the worm is coughed up and swallowed to mature in the intestine; begin sucking blood and laying eggs.

What are the signs of Hookworm infestation?

Signs may include any or all of the following: Inapparent infestations; nonspecific diarrhea; dark black (tarry) diarrhea; bloody diarrhea; vomiting; poor or no appetite, pale mucous membranes in the mouth and generalized pallor; weakness, emaciation and poor growth. Anemia can be so severe as to cause death.

What is the treatment?

It is easy to get rid of Hookworms. Just give any effective oral wormer. My favorite is any brand with pyrantel pamoate as the active ingredient. This is generally well tolerated by the pet, safe and effective. If the animal is severely anemic, blood transfusions and supportive care may be required. It is best to worm breeding female dogs and cats before breeding and again 3, 6 and 9 weeks after whelping. Juveniles migrating through the body will not be killed by conventional wormers.

This is why we like to worm puppies and kittens twice three weeks apart and then check a fecal specimen three weeks later. This allows all migrating juveniles to reach the intestine where they are easily killed. Since Hookworm eggs and larva build up in damp soil, often times the dogs tied out on dirt or in soil runs need to be moved to a non-infested area to prevent reinfection. If this is impossible and the pet keeps becoming reinfected, I suggest keeping the dog on Filaribits Plus (a daily heartworm preventative with a low level wormer included which kills Hookworms, Roundworms and Whipworms) for a year or more while the Hookworm larva and eggs die off. Concrete surfaced runs or runs with deep pebble coverings allow the surface to dry allowing sunlight to kill the larvae. Fecal Examinations: Young dogs and cats should have a fecal floatation done twice a year to detect Hookworm eggs

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