Flies in Veterinary and Animal Health

Introduction to Flies

  • The lecture focuses on flies, referencing their life cycle and pathology.
  • Flies have a standard life cycle; adults lay eggs.
  • Most flies have wings, except for a few exceptions mentioned in the lecture.
  • Flies are part of a large order, covering only a small portion of species.
  • Classification of flies is based on the pathology they cause, either as adults or larvae.
  • Flies undergo complete metamorphosis.

Common Clinical Signs Related to Flies

  • Bites:
    • Flies inflict bites; some can be painful, while others are merely annoying.
    • Animals can have hypersensitivity reactions to fly bites.
  • Warbles:
    • Flies can cause subcutaneous lumps (warbles) under the skin.
  • Anemia:
    • Heavy fly infestations may lead to anemia in animals.
    • Generally, flies are viewed as annoying rather than severely pathological.
  • Specific mention of screw worms, which cause serious damage and pathology.

Female Blood-Feeding Flies

Cucodius species (Nosceums)

  • Common Name: Nosceums
  • Scientific Name: Cucodius species
  • Notable for painful bites, especially active at dawn and dusk during summer.
  • Can cause allergic reactions leading to alopecia (sweet itch).
  • Breeding tends to occur near stagnant water.
  • Prevention:
    • Use of fly sprays, masks, and sheets for horses.

Simulium species (Black Flies)

  • Common Name: Black flies; also referred to as Buffalo gnats.
  • Painful bites from scissor-like mouthparts.
  • Swarm around head, neck, and ears, making them difficult to swat.
  • Can cause cattle and other animals to stampede due to irritation.
  • Diet: Females suck blood for egg-laying; males feed on pollen.
  • Prefer swift, fast-running water for breeding.
  • Prevention: Fly sprays and masks are effective.

Mosquitoes and Related Species

Anopheles species and Culex species (Mosquitoes)

  • Transmit diseases like heartworm.
  • Found around water; can use specific products to prevent larval hatching in water bodies.
  • Products can be chemical yet safe for animals.

Chrysops species (Deer Flies)

  • Large black and gold flies that prefer mammals and humans.
  • Notable for blood laceration and feeding, can also transmit diseases like anthrax and EIA (equine infectious anemia).

Sheep and Goats Specific Flies

Melophis oblivious (Sheep Head Fly)

  • Description: Wingless variety that deposits larvae onto wool/hair of hosts.
  • Lifecycle: Short lifecycle; pupating within hours advantageous for the pest.
  • Infests sheep/goat skin; can cause anemia and irritation due to feeding.
  • Prevention/Treatment: Main treatment includes ivermectin; can bite humans.

Tsetse Fly

Glossina species

  • Common Name: Tsetse fly
  • Causes African sleeping sickness in mammals, reptiles, and humans.
  • Sharply elongated proboscis for feeding.
  • Short lifecycle with females laying 4-6 eggs in their life.

Horn Fly and Stable Fly

Haematobia irritans (Horn Fly)

  • Hosts include cattle, elk, buffalo, and deer.
  • Prefer warmer areas of animals (e.g., head, neck).
  • Lay eggs in manure; frequent blood suckers causing irritation and potential anemia.
  • Prevention: Clean manure, spread to dry.

Stomoxys calcitrans (Stable Fly)

  • Found in decaying vegetation; affects animals and humans alike.
  • Prefer feeding on legs, abdomen, and ears. Can slow animals down due to irritation.

House Flies and their Effects

Musca domestica and Musca autumnalis (House Flies)

  • Common Name: House flies
  • Not extensively covered, though connected with diseases due to their habits of food contamination.

Calliphora species (Blow or Bottle Fly)

  • Metallic appearance; known for spreading maggots and pathogens.
  • Feeding habits include vomit-based liquefaction of food spread diseases.
  • Requires careful wound care to prevent infection.

Larval Infestations and Health Impact

Cuterebra Species (Cudarebra)

  • Infests multiple small mammals, dogs, and cats.
  • Cause of skin holes and potential migration to critical body parts.
  • Carefully handle to avoid releasing toxins.

Hypoderma species (Warbles)

  • Typically affects cattle and bison, presenting breeding holes on the skin.
  • Lifecycle can last up to a year; notable behavior changes in infested animals.
  • Treatments include poron which helps ease infestation.

Gastrophilus species (Equine Stomach Bot)

  • Affects various large mammals, notably horses.
  • Adult flies lay sticky eggs on hair, leading to ingestion and larval development in the stomach, causing lesions and abscesses.

Conclusion

  • The lecture concludes with a reminder to review for practical and final exams.