Flies of horses

Question 1

Flies belong to which class?

Answer 1

Insecta

Question 2

Which family of flies is of most veterinary importance and why?

Answer 2

Muscidae - feed on secretions and some suck blood

- collectively called nuisance flies

Question 3

Which species of fly is known as the ‘Stable fly’?

Answer 3

Stomoxys calcitrans

Question 4

Describe the life cycle of Stomoxys calcitrans

Answer 4

• Feeds on blood
• Breeds inside liveries, barns, stables
• Eggs in dung are mixed in with straw and urine, damp silage/sheltered compost heaps
• Populations build up
• Dispersal between livestock on adjacent pastures

Question 5

Where does Stomoxys calcitrans feed on the host?

Answer 5

Lower parts of the animal, especially the legs and flanks

Question 6

What are the host responses to Stomoxys calcitrans?

Answer 6

• Stamping feed
• Shivering the skin
• Rapid head turning
• Tail swishing
• Gadding (sprinting off)

Question 7

Why are Stomoxys calcitrans a worry?

Answer 7

• ‘Fly worry’
• Economic importance
• Mechanical pathogen transmission

Question 8

What are the two species of Muscidae non biting flies?

Answer 8

Hydrotaea irritans - The headfly

Musca autumnalis - The face fly

Question 9

How can Hydrotaea irritans be grossly identified?

Answer 9

Orange wing base and greenish abdomen

Question 10

How do Hydrotaea irritans emerge as a problem?

Answer 10

One generation a year in July
Emerge on mass
Typically on wooded pasture
Most active on overcast warm days

Question 11

Where are Musca autumnalis found to affect horses?

Answer 11

On the eyes, muzzle and face

Question 12

Describe the life cycle of Musca autumnalis

Answer 12

• Pastured animals outdoors
• Develops on dung on pasture
• Populations build up in late autumn

Question 13

Which disease is transmitted by Musca autumnalis?

Answer 13

Pink eye: Infectious bovine Keratoconjunctivitis

Question 14

What are the two species of biting non-Muscidae flies?

Answer 14

• Tabanids

- Culicoides spp

Question 15

Which species has a large body and head with stubby mouthparts

Answer 15

Tabanids

Question 16

Where do tabanids breed?

Answer 16

In wet pastures, marshy lands, edges on ponds

Question 17

What are the two genera of tabanids of veterinary importance and how can they be identified?

Answer 17

Tabanus - Large with clear wings

Haematopota - mottled wings

Question 18

Tabanids are mechanical vectors of which 3 diseases?

Answer 18

• Equine infectious anaemia
• Trypanosomes
• Bovine anaplasmosis

Question 19

Describe the appearance of Culicoides spp

Answer 19

• Wings brownish
• Black body and mottles
• Spots on wings

Question 20

Describe the life cycle of Culicoides

Answer 20

• Dig a whole and feed on free blood
• Eggs laid in damp compost heaps
• Egg to adult in less than 3 weeks
• one/two generations a year

Question 21

Which fly causes sweet itch?

Answer 21

Culicoides

Question 22

What is the only known vector of Blue tongue in ruminants?

Answer 22

Culicoides

Question 23

Which fly requires flowing waters to support their life cycle?

Answer 23

Simulium spp - black flies

Question 24

What is myasis?

Answer 24

The invasion of living tissue by the larvae of dipterous flies

Question 25

Which fly species is know as the horse bot fly

Answer 25

Gasterophilus spp

Question 26

How can flies be controlled on liveries and farms?

Answer 26

• Fly insecticides: mainly SPs, can have insecticide ear tags for cattle
• Dung removal inside housing