internal and external parasites that effect horses

Species of bot flies

what are Gasterophilus intestinalis, Gasterophilus nasalis, and Gasterophilus hemorrhoidalis?

Gasterophilus intestinalis

Bot flies that lay eggs on forelegs and shoulders

Gasterophilus nasalis

Bot fly that lay eggs on the throat and jaw

gasterophilus hemorrhoidalis

Bot fly that lays eggs on the nose and muzzle

Life cycle of the horse bot fly

Ingested by the horse by licking motion primarily during the summer months, the larvae enter the mouth where they hatch and burrow into the gums, then are swallowed or migrate to the horse's stomach where they attach to the lining. They remain there during the winter months and pass out in late winter or early spring via feces, maturing to the adult bot fly in soil or dried manure.

Scientific name for roundworms

Parascaris equorum.

Location of roundworms in horse's digestive tract

Small intestine.

Coughing during a roundworm infestation is caused by what?

Roundworm larvae traveling to the lungs after entering the small intestine.

Lifecycle of the roundworm

The horse ingests the eggs via contaminated feed, water or soil; the eggs travel to the small intestine, larvae migrate through the lining to the liver and then to the lungs, are coughed up and swallowed, mature in the small intestine, and pass out eggs via feces.

Most common parasite found in horses

Strongyles.

Small strongyles

Also known as Cyathostomes or red worms.

Location of small strongyles in the horse

Cecum and large intestine.

Internal parasite causing colic and diarrhea

Small strongyles feed on the lining of the large intestine and migrate to the intestinal wall.

Species of large strongyles

There are 3 species: Strongylus vulgaris, equinus, and edentatus.

Strongylus vulgaris

Also known as blood worms because it invades blood vessels causing clots or thrombosis to the intestine, leading to intestinal death.

Tissues invaded by strongylus equinus and edentatus

Cecum, large intestine, liver, and pancreas.

Anoplocephala

Also known as tapeworms; infestations may be found at the ileo-cecal valve causing diarrhea or intussusception.

Parasite found in horses grazing with donkeys

Lungworms.

Parasite laying eggs around the anal opening

Pinworms cause anal itching and tail rubbing.

Location of pinworms in the horse's digestive tract

Large intestine.

Common name for oxyuris Equi

Pinworms.

Parasite transmitted to foals via the mare's mammary gland

Threadworms.

Cause of foal heat diarrhea

Threadworms travel to the small intestine of the foal about 10 days after birth.

Activation of larval stages in mares

Activated by parturition and travel to the mammary gland.

Scientific name for threadworms

Strongyloides westerii.

Symptoms of roundworm infestation

Weight loss, colic, lethargy, cough.

Intermediate host for tapeworms in horses

Orbatid mites.

Life cycle of stomach worms

Stomach worm larvae are ingested and develop in the stomach.

Stomach worm eggs

Passed through the feces and carried by the intermediate host fly to mouth, nose, and open wound, causing summer sores.

Primary reservoir host for lungworms

Donkey

Parasite commonly found in horses grazing with cattle

Hairworms

Typical life cycle of parasites affecting horses

Egg, larvae, adult

Typical protocol for horse deworming

Rotational deworming (based on season)

Excessive use of deworming agent

Leads to resistance among parasite population

Worms in refugia

A portion of parasite population not exposed to a deworming agent

Fecal threshold importance

Keeping it at 100-500 eggs per gram to avoid resistance

Deworming for roundworms and threadworms in foals

Should begin around 3 months of age

FEC

Stands for Fecal egg count

Categories of flies

Biting and non-biting; biting suck on blood and non-biting feed on secretions.

Biting flies examples

Stable fly, horse fly, deer fly, horn fly, black fly, and gnat

Non-biting flies examples

House fly and face fly

Life cycle stages of the fly

Egg, larvae, pupa, and adult

Scientific name of the stable fly

Stomoxys calcitrans

Scientific name of the house fly

Musca domestica

Scientific name of the face fly

Musca autumnalis

External parasite causing encephalitis in horses

Mosquito

Mosquito feeding behavior

Females feed on blood and males feed on plant nectar

Scientific name for lice infestation

Pediculosis

Lice eggs

Referred to as nits

Spread of lice infestation

Contact with brushes, combs, blankets

Condition known as mange in horses

Caused by mites

Types of mites

Biting (Psoroptic) and burrowing (Sarcoptic)

Diseases carried by ticks

Lyme disease and piroplasmosis

Life stages of the tick

Egg, larvae, nymph, and adult

Category of infection caused by ringworm

Fungal

Common name for ringworm

Girth itch

Black fly behavior

Prefers to congregate in swarms, especially inside the ears.

Fly causing sweet itch

Biting midge, punkies, or no see-ums

Necessary conditions for fly life cycle

Breeding material, warmth, and moisture

Most important step in fly management control system

Elimination of breeding material

Non-chemical method of biological control of flies

Parasitic wasp that deposits eggs in fly pupa, killing or consuming the fly

Methods to manage flies

Screening feed rooms, tack rooms, and stalls; judicious use of insecticides; biological control

Preferred insecticides for controlling flies

Wettable powders as they stay longer

Larvicide

Insecticides targeted to the larval stage of development

Indication of cattle grub in horses

Hard nodules under the skin near head, neck, wither, or ribs

Conditions transmitted by ticks

Lyme disease, tick bite paralysis, piroplasmosis, Equine Granulocytic Ehrlichiosis, mountain tick fever

Types of lice found in horses

Biting and sucking