ANSC 221_ExternalParasites_PPT9_sp22 (1)

ANSC 221 Equine Handling & Safety

• Course Title: Equine Handling & Safety

• Professor: Sarah Schobert

• University: Texas A&M University, Animal Science Department

External Parasites

Types of External Parasites

• Common external parasites include:

  • Flies

  • Mites

  • Ticks

  • Lice

  • Gnats

  • Mosquitoes

• Effects on Horses:

  • Irritate and injure horses

  • Can carry diseases leading to health problems

Health Impacts of External Parasites

• Blood-sucking behavior leads to:

  • Dermatitis

  • Failure to thrive

  • Anemia

  • In severe cases, can result in death

Life Cycle of Flies

Stages of Development

• Flies undergo four stages:

  • Egg

  • Larva (maggot)

  • Pupa

  • Mature Adult

• Life Cycle Duration:

  • Completion can take a few weeks (some species up to a year)

Non-biting Flies

Major Non-biting Flies

• House Fly

• Face Fly

• Bot Flies

• Characteristics:

  • Feed on secretions (eyes, nose, mouth) and open wounds

  • Bot flies do not bite; they lay eggs on horse hair

Biting Flies

Types of Biting Flies

• Include:

  • Stable Fly

  • Horsefly

  • Deer Fly

  • Horn Fly

• Bloodsuckers typical of most gnats and black flies

Housefly and Stable Fly Impact

• Breeding Grounds:

  • Lay eggs in manure and decomposed plant debris

• Feeding Habits:

  • Feed primarily during the day

  • Transmit diseases like:

    • Equine Infectious Anemia (EIA)

    • Anthrax

    • Summer sores

Housefly and Stable Fly Behavior

Feeding and Transmission

• Feed on secretions from eyes, nose, and mouth

• Transmission of:

  • Contagious conjunctivitis

  • Eyeworms

• Effects of Stable Fly Bites:

  • Produce painful nodules and black scabs

Control Measures for Housefly and Stable Fly

Recommended Strategies

• On Property:

  • Use residual insecticide sprays

  • Quick-kill space sprays or foggers

  • Fly baits

• On Horses:

  • Insecticide hand wash or mist spray

  • Effective chemicals: Pyrethrins and piperonyl butoxide

  • Repeat applications at least every other day

Face Fly and Horn Fly

Characteristics and Control

• Breeding Grounds: Cow manure, affecting horses near cattle

• Face Fly Feeding: Causes irritation on mucus secretions

• Face masks serve as exclusion devices and insecticide wipe-on for control

Horse Fly and Deer Fly

Impact and Control

• Known for painful bites leading to blood loss

• Vectors for numerous diseases (e.g., equine infectious anemia)

• Laying eggs in moist soils; stabling can reduce exposure to flies

Blowfly and Screwworm Fly

Behavior and Prevention

• Lay eggs in open wounds; critical sites include castration and trauma wounds

• Recommended wound care management: dust/powder or aerosol spray weekly

Gnats

Common Species

• Buffalo gnat and "no see ums" (Culicoides)

• Transmission of vesicular stomatitis

• Symptoms: Itching, dermatitis, hair loss from repeated attacks

Vesicular Stomatitis Virus (VSV)

Symptoms and Identification

• Affected areas: mouth, tongue, nostrils, ears, and more

• Symptoms include scabbing, drooling, and lameness

Mosquitoes

Risks and Control

• Key transmitters of diseases (Eastern, Western, Venezuelan equine encephalomyelitis and West Nile Virus)

• Sensitive horses can develop allergies to their bites

• Eggs laid directly on water; control by eliminating standing water

Prevention of Mosquitoes

Control Strategies

• Use commercial larvicides in water (Bacillus thuringiensis ssp. israelensis or methoprene)

• Mosquitoes are less effective flyers; fans can help prevent landing

Lice

Types and Effects

• Main species include:

  • Biting lice: Feed on skin scales

  • Sucking lice: Feed on blood

• Infestation symptoms:

  • Anemia, weight loss, rough haircoat

Identification and Treatment

• Adult lice size: 2-3 mm, visible by parting hair

• Eggs (nits) appear like white grains of sand on hair shafts

• Infestations common in winter; topical insecticides and oral dewormers such as ivermectin recommended

Chiggers

Characteristics and Management

• Known as red bugs; larvae of mites

• Cause itching and skin damage when horse is their host

• Use repellents and residual insecticides; pasture treatments recommended

Ticks

Prevalence and Risks

• Found throughout the country, especially in spring and fall

• Diseases transmitted include Lyme disease, equine piroplasmosis

• Tick bites can lead to screwworm attacks and anemia

Tick Prevention

Recommended Strategies

• Maintain low grass and weeds

• Treat premises with effective insecticides

• Use repellents labeled for ticks before and after riding