Dogs Lesson:#9 Class:Small Animal Science Objective:Students will be able to identify the types and...

Dogs

Lesson: #9

Class: Small Animal Science

Objective:Students will be able to identify the

types and signs of internal and

external parasites that affect dogs.

Internal and External Parasites in Dogs

Ascarids – Roundworms

•4 to 8 inches in length•Egg laying adults live in small intestines of dogs less

than 6 months old.

Infection of Roundworms

•Caused by:1. Ingestion of eggs2. Transmission of mother dog to unborn pups.3. Transmission of mother dog to nursing pups.

Development

•The small larvae hatch in the dogs stomach.•Grow to an adult worm that begins to produce eggs in

about 12 weeks.•Older dogs develop a resistance to the adult worm.

1. When they ingest an infected egg, the hatchedlarvae does not grow.

How are they passed on to the pups?•Pregnant Dog

Roundworms to mother dogs liver

Transfer via blood from liver through umbilical cord to Pups liver.

Go to lungs

Coughed up from the lungs

Swallowed into pups stomach

•Lactating dog1. Roundworms can be passed thru milk.

Signs

•Depends on the number of worms present.•Several hundred worms growing to adults – pup will

appear pot bellied.•Pups will become thin because of deprivation of

nutrients.

Treatment

•Treatment of pups need to be done early.•Treat pups at 2, 4, 6and 8 weeks of age.•There are several drugs that a veterinarian can

prescribe.

Hookworms

• Bloodsucking parasites• Adult – 1 inch long• Has a large mouth that attaches to small intestines.• This causes a small bleeding site.• When several hundred worms are present, the loss

of blood can be dangerous.

Signs

•Blood in intestine causes dark colored feces.•Gums of animal will be white.•Weak and lacking energy.

Infections

•Both young and adult can be infected.•Shed eggs in dogs feces.•Hookworm eggs hatch into larvae.•Larvae can penetrate dogs skin when they lie down in

contaminated places.•Can be ingested with contaminated food or water.

Development

•Larvae grow to egg laying adults in about 2 weeks.

Signs

•Pups show signs of anemia at 2 weeks of age.•May die by 3 weeks of age is the number of worms is

great.

Treatment

•Older dogs should receive a single, one-day dewormingonce or twice a year.

•Young females/pups same as roundworms.

Whipworms

•Live in the lower digestive track of dogs especially thececum.

•The adult worm is broad at one end and narrow at the other.•About 2.5 inches long•Thread there narrow end into the lining of the cecum.•Produce football shaped eggs than live in the soil for

several years.

Signs

•Irritation to the gut lining.•Cause loss of fluids.•Watery feces that is tinged with blood.•Dogs can become dehydrated which can cause death.

Prevention and Treatment

•Dewormers available through veterinarians.•Do not place back in the same yard.

Life Cycle

Tapeworms

•Flat segmented worms.•Usually 1 foot in length.•Live in small intestine.

Spread

•Tapeworms shed their eggs filled terminal segments infeces of infected animals.

•Segments are about the size of a grain of rice and canbe seen by the naked eye.

Life Cycle

Four types of tapeworms:

1. Didlylidium caninum2. Taenia pisiformis3. Echinococcus granulosus4. Echinococcus multilocularis

Intermediate hosts depend in the type of tapeur.

•Diplylidium – fleas•Taenia – wild rabbits

Treatment

•Eliminate the hosts.

Heartworms

•Live in heart or artery that carries blood to the heart.•Thin – 6 to 14 inches long.

Damage

•Vital organs are affected.1. Lungs 2. Enlarged heart

3. Liver and kidneys becomedamaged.

Signs

•Frequent coughing•Sluggishness•Rapid tiring•Labored breathing

Life cycle

Transmission

•By mosquito•When a mosquito bites an infected dog, it takes up the

blood that may contain microfilariae.•Larvae develops in mosquito for about 2 weeks.•The mosquito bites another dog, the infected larvae are

passed on.•The larvae move through the tissues of the body for 2 to 3

months and enter the heart.•They reach adult size in the heart in another 3 months.

Prevention and Treatment

•3 drugs available•Dermal treatment of ivermectin can also be effective.•Can be treated if caught early.•Arsenical drugs can kill heartworms.

Chest exray of mildly affected dog

External Parasites

•Dogs are infected by:

TicksFlea

Mite

Lice (female)