External Parasites

1. External Parasites Biting insects that suck blood Vectors of encephalomyelitis Flies ____ _____ hatches into maggots which feed on dead tissue Lifecycle stages are: egg, larva, pupa, adult Best way to control is to remove manure and decaying vegetable material There are both biting and sucking kind Attach eggs, called nits, to the hair, close to skin Lice Eggs hatch in 11-20 days Females lay eggs 11- 12 days of age Can only exist about 3 days when off the host animal Treat by spraying, sponging or dusting and repeat in 2-3 weeks Cause mange Mites So small must be viewed under microscope Chorioptic type may cause foot mange resembling scratches Females lay 10 to 25 eggs during laying period which lasts 12-15 days Eggs hatch in 3-10 days Dust is not effective, must spray or use a wet brush wash, repeat every 7 days Cause piroplasmosis The _____ ________ caused African horse fever Ticks Lifecycle stages are: egg, 6 legged larva or seed tick, 8 legged nymph, adult Treat by dipping entire animals Breathe by spiracles or holes on their abdomen Caused by various species of fungi, arranged in circles on the skin Causes severe itching, infection may lead to abscesses Lesions are usually covered with grayish crusts Ringworm Treat with warm soap and water to soften crusts, paint with tincture of iodine daily for 1 – 2 weeks The disease this parasite causes can be spread to children

2. External Parasites Flies Lice Mites Ticks Ringworm

3. Internal Parasites Lays yellow eggs on legs, chest, belly and neck. Also chin, throat, nostrils and lips. Bot Fly Horse licks or bites stimulating hatching of eggs Larvae burrow into the tongue and travel to the stomach Mature in stomach in 9 months Mature larvae burrow into the ground, turn into pupa and in 15-17 days they emerge to begin the cycle again Active from early spring to first freeze Treated with anthelmintic Cycle must be broken by killing the flies, egg removal or deworming Primarily affects young horses Swallowing eggs in feed, pasture and water infects young horse Larvae migrate to small intestine, liver and lung tissue Cause digestive problems, intestinal and blood vessel blockage, colic and possibly death Ascarids (Roundworms) Measure 5 to 22 inches in length Lifecycle is about 3 months Female worms lay up to 200,000 eggs per day Deworm foals every two months for 1st year to prevent Unthriftiness, pot belly, rough coat, lack of growth and cough are signs of infestation Most common form of equine internal parasites Found in large intestine Lays several thousand eggs per day Strongyles (Bloodworms) Larvae climb to upper portions of pasture grasses and are swallowed by horses grazing Large strongyle larvae migrate into arties and cause blood clots Small strongyles migrate thru liver and large intestine causing diarrhea and colic Infests young foals that ingest larvae in the dams milk or by larvae in bedding Stronglyoides (Threadworms) Larvae migrate through lungs and small intestine Foals become dehydrated and developer chronic diarrhea White-appearing worms with long slender tails Seen in feces of affected horses Pinworm Worms mature in large intestines and females full of eggs travel to small colon, rectum and crawl out anus Causes horse to rub tail against posts, this crushes the adult but leaves eggs glued to anal region

4. Internal Parasites Bot Fly Ascarids (Roundworms) Strongyles (Bloodworms) Stronglyoides (Threadworms) Pinworm