Canine Parasites Flashcards
Toxocara canis (Roundworms)
- 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
Toxocara canis (Roundworms) lifecycle
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
Roundworms in Pups
- 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 )
Roundworm eggs
- 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
Roundworms: Visceral and Ocular Larva Migrans
- 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
Toxocara precautions
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
Why in Madison are dogs not allowed on school grounds, beaches, etc?
Roundworm prevention?
Hookworms
- 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)
Hookworms: Cutaneous Larva Migrans
- 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
Whipworms
- eggs can remain in soil for years - hard to get rid of
Tapeworms
- 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
Heartworm
- 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!
Heartworm lifecycle
- Mosquito bites infected human or dog
- bites another dog and infects them
Heartworm Prevention
- 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
Heartworm Treatment
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
Fleas
- 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
Number of Fleas and Life Cycle
- 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
Flea Treatment
- Treatment of all pets and environment
Ticks
- Can cause anemia, skin disease
- Biggest problem is that they carry other diseases
- Lyme disease
Lyme Disease
- 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
Ear Mites
- 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
Mange Mites
- 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
