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 eggs 2. 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 hatched larvae 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 dog 1. 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 deworming once or twice a year. Young females/pups same as roundworms.

Whipworms Live in the lower digestive track of dogs especially the cecum. 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 in feces of infected animals. Segments are about the size of a grain of rice and can be seen by the naked eye.

Life Cycle

Four types of tapeworms: 1.Didlylidium caninum 2.Taenia pisiformis 3.Echinococcus granulosus 4.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. Lungs2. Enlarged heart 3. Liver and kidneys become damaged.

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: Ticks Flea Mite Lice (female)