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Name
Roundworm Infection, Canine
Short Description
Toxocara canis, Toxocara leonina
Affected Animals: Dogs and cats can develop adult worm infections
within the digestive tract. The larval stage of the roundworm can
cause serious damage in the human, but they cannot develop into the
adult form in species other than the dog or cat. Dogs are affected
by both the Toxocara canis and the Toxocara leonina species, but
cats only become infected from the Toxocara leonina.
Overview:
Almost all puppies are born already infected with
roundworms, which are the most common intestinal parasite of the
dog. Toxocara canis, a species of roundworms, is capable of
migrating across the infected mother dog's placenta and into the
unborn puppies. Neonates also can ingest the infective form of the
roundworm when nursing infected milk from their mother.
Other possible modes of roundworm infection include either ingestion
of infective eggs from the environment or from prey that harbor the
parasite. Large numbers of eggs can be spread into the environment
by an infected dog. These eggs are a human health hazard if
accidentally ingested and can cause vision impairment or other
serious diseases.
Roundworm adults are fairly long, white, and tubular in shape and
have been said to resemble half-lengths of spaghetti noodles. These
worms swim inside the small intestine and feed on the animal's
digested food. Because roundworms can grow to be eight to 12
centimeters long, an infection of multiple adults is capable of
causing inflammation and distention of the bowel loops. This can
lead to colic, interference with normal contractions of the
intestines, and the inability to absorb the nutrients that the dog's
body needs. A severe roundworm infestation actually can result in a
blockage of the intestines and possible death.
Roundworms can lead to a host of medical problems in dogs, including
stunted growth among puppies that are infected early in their
development. Puppies are more likely than adult dogs to develop
serious symptoms. Fortunately, there are safe and effective
treatments and measures of prevention that will keep canines healthy
and limit the spread of infection to others.
Clinical Signs: Diarrhea, a poor hair coat, colicky pain,
decreased appetite, and a pot-bellied appearance to the abdomen may
be seen. Some animals can develop liver problems, pneumonia, or
stunted growth. If roundworms get to the stomach, the animal may
vomit up some of the worms.
Symptoms: Diarrhea, a poor hair coat, abdominal discomfort
evidenced by moaning or groaning, decreased appetite, and a
pot-bellied appearance to the abdomen may be seen. Some animals can
develop liver problems, pneumonia, or stunted growth. If roundworms
get to the stomach, the animal may vomit up some of the worms.
Description:
Both dogs and puppies can be infested with a
common intestinal parasite called the roundworm, but the infection
tends to have a more severe effect on puppies. The roundworms, or
ascarids, of the dog are Toxocara canis and Toxocara leonina.
Toxocara canis is the most common species that affects canines;
almost all puppies are born already infected by their mother. Other
possible modes of roundworm infection include either ingestion of
infective eggs from the environment or prey that harbor the
parasite.
These long, white, tubular adult worms can reach lengths of eight to
12 centimeters long. The roundworms live in the small intestine,
moving against and feeding upon the flow of food being digested by
the animal. When multiple worms are present, they are capable of
causing inflammation and distention of the bowel. As a result,
canines with roundworms can experience colic and will not absorb
needed nutrients from the food they eat. Diarrhea is a common
symptom of an infection, but more serious problems can occur.
Canines with roundworms often have a potbellied appearance and an
unhealthy coat.
Roundworms pass large numbers of microscopic, round eggs in the
feces of the infected dogs. If these eggs are spread in an
environment conducive to infestation, they will mature and become
ready to infect the next animal. Humans, most commonly children, can
become afflicted by the Toxocara canis larval stage by accidentally
ingesting soil or feces containing roundworm eggs. In people, the
larvae can migrate through the eyes and other important organs,
leading to vision impairment or other serious illnesses.
Diagnosis: Diagnosis is established by obtaining a fresh
fecal sample and identifying the characteristic eggs under the
microscope. This procedure is called a fecal floatation examination.
Prognosis: Animals that get proper medical treatment have a
good prognosis. Although uncommon, roundworms can cause fatal
disease in young puppies if they obstruct the bowel or cause damage
when migrating through organs like the lungs or liver.
Transmission or Cause: Transmission of roundworms to puppies can occur
through various methods. Most commonly, however, infection occurs
from an infected mother passing the roundworms to the unborn puppies
through the placenta. Young animals can also get roundworms from the
milk while nursing. Additional causes are the ingestion of infective
eggs in the environment or prey that harbor the parasite.
Treatment:
Treatment entails deworming the pregnant dog
multiple times starting in the third trimester (day 42 of pregnancy)
through the second week of lactation. Puppies also will need to be
treated with a dewormer that is safe for young animals. Safe and
effective deworming medications such as fenbendazole or pyrantel
pamoate will eliminate a large percentage of the roundworm eggs.
Puppies should be treated for worms soon after birth and every two
weeks thereafter until the animal is 12 weeks of age. Treatment
schedules vary based on the environment and the degree of worm
infestation. The examining veterinarian can recommend the most safe
and effective drug, dose, and schedule for an individual mother and
puppies. Use caution if purchasing over-the-counter dewormers since
many do not eliminate all of the types of roundworms that can infect
a dog.
Prevention:
The mother dog should be dewormed during her
pregnancy and period of lactation; the use of a treatment such as
fenbendazole eliminates 99 percent of the roundworm larvae that
infect puppies. Puppies, too, must receive treatment on a regular
schedule shortly after birth.
Additional preventive measures include keeping the animal's
environment clean of feces. Dogs should be monitored to ensure that
they do not consume feces or hunt and ingest prey.
To prevent the potential for human health hazard, pet owners should
dispose of dog feces deposited in yards, parks, and playgrounds.
Strict hygiene is critical in preventing humans from being infected.
Wearing gloves when gardening or working in areas that can be
contaminated with eggs, covering sandboxes when not in use, and
washing hands thoroughly prior to preparing and eating food are all
important measures in maintaining hygiene and preventing disease. In
addition, parents should ensure that children to do not play in
potentially infected areas.
