Canine Parasites

Question 1

Toxocara canis (Roundworms)

Answer 1

• very common in dogs, infects canines as primary host
• 20% of adult dogs, 98% puppies - every pup will have roundworms
• Adults are often asymptomatic
• Symptoms: round stomach

Question 2

Toxocara canis (Roundworms) lifecycle

Answer 2

Multiple potential sources of infection
* ingestion of contaminated soil or dog feces
* eating infected animals
* transplacental/transmammary

Transmissible to Humans

Adults in lumen of intestine, juveniles migrate through tissues throughout development

Question 3

Roundworms in Pups

Answer 3

• Most pups are infected transplacentally when encysted larva in the mother reactivate and migrate into the fetal pups
• Pups can also be infected transmammary, through the milk of the mother
• often will start treatment to deworm at 2 weeks of age (continue at 4, 6, 8 )

Question 4

Roundworm eggs

Answer 4

• are resistant to environment and chemicals and can survive 2-6 years in environmental conditions
• sandboxes were contaminated with them - easy for kids to get infected

Question 5

Roundworms: Visceral and Ocular Larva Migrans

Answer 5

• Worms travel around body and cause inflammation and damage. Immune system plays a role in disease

Visceral
* abdominal pain, cough, fever, itchy skin, etc

Ocular
* eye-pain, decrease visual acuity, blindness - there was a time when there were many kids that were blind in one eye

Question 6

Toxocara precautions

Answer 6

Prevention
* reduce infection rate through treating infected animals
* dispose of feces properly (burining or garbage disposal)
* limit defecation in areas where people will be
* wash hands after playing outside, especially before eating
* don’t let kids eat dirt

Question 7

Why in Madison are dogs not allowed on school grounds, beaches, etc?

Answer 7

Roundworm prevention?

Question 8

Hookworms

Answer 8

• Can be caused by multiple genera and species
• Attach to intestine and “suck” blood
• Eggs develope and “hatch” outside body in warm, wet areas
• Infective larva may be swallowed or penetrate through the skin and migrate to intestine
• Can cause anemia, especially in pups (can lead to death)

Question 9

Hookworms: Cutaneous Larva Migrans

Answer 9

• Humans are an incidental “dead-end” host for the most common types
• If you scratch, you can get bacterial infections and rashes
• Migration of parasite causes dermatitis
• hookworms don’t continue to mature and eventually die

Question 10

Whipworms

Answer 10

• eggs can remain in soil for years - hard to get rid of

Question 11

Tapeworms

Answer 11

• Intestinal parasite
• “Eggs” look like rice in the stool - you may notice this
• Commonly infected by ingesting fleas - flea larvae ingested eggs
• A few can infect humans
• Can cause severe liver damage (rare)
• Don’t usually cause significant illness in dogs or cats

Question 12

Heartworm

Answer 12

• Interesting life cycle
• Often don’t see symptoms until very bad
• Worms live in the heart
• Dogs may tire much more quickly
• Fainting spells or heart attacks
• Found around the world and hosts include coyotes, foxes, etc
  * Transmitted by mosquitoes - Vector-borne disease!

Question 13

Heartworm lifecycle

Answer 13

• Mosquito bites infected human or dog
• bites another dog and infects them

Question 14

Heartworm Prevention

Answer 14

• Prevention much better than treatment
• Limit exposure to mosquitos if possible (outdoor dogs more susceptible)
• Test to make sure dog is not already infected
• Monthly pills are the most common
• 12-month injection is available
• works by killing larvae in bloodstream

Question 15

Heartworm Treatment

Answer 15

When dog has adult heartworms
* Treatment is to kill adult worms, dangerous and expensive
* uses a form of arsenic

Dead worms must be broken down and cleared from dog’s system
* can obstruct the arteries
* can cause shock

Question 16

Fleas

Answer 16

• Cat flea is most common
• Fleas suck blood for reproduction, adults are the only parasitic stage
• Flease lay on animal, but many fall off into environment
• Many flea treatments only kill adult fleas
• Fleas do not use humans as host but will bite if there are no other hosts available
• The fleas themselves don’t cause much problem to dog - dog has an allergic response to fleas that causes dermatitis - itchy, scratch hair off

Question 17

Number of Fleas and Life Cycle

Answer 17

• Adult fleas can not survive without a blood meal
• Larvae do not suck blood
• Larval stages can survive the winter
• Breaking the cycle with an insect growth regulator or an insect gorwth inhibitor instead of just killing the few adults is the key to control
• Not uncommon to have huge outbreak of fleas because cocoon will sense energy around and break open to an adult flea
• Eggs - Caterpillar - Cocoon - Adult flea

Question 18

Flea Treatment

Answer 18

• Treatment of all pets and environment

Question 19

Ticks

Answer 19

• Can cause anemia, skin disease
• Biggest problem is that they carry other diseases
• Lyme disease

Question 20

Lyme Disease

Answer 20

• Bacterial disease but spread by ticks
• Can infect humans and dogs
• Can cause arthritis, heart muscle inflammation, fever, etc
• Vaccines are available
• Is treatable with antibiotics

Question 21

Ear Mites

Answer 21

• Infect external ear canal dogs and cats
• Cause inflammation, thick red-brown discharge and may go to rump
• Scratch ear and head frantically
• Treatment is typically oil that will kill the mites
• Life cycle entirely in ear
• Very contagious - if one of your animals has it, treat all pets in house

Question 22

Mange Mites

Answer 22

• Caused by different kinds of mites
• Some are transmissible to humans
• Thought that all dogs have them, but with a healthy immune system there will be no disease. Immune suppression causes disease to surface
• hair loss, scratching, infection