Some adult flies damage animals (bite, irritate). Some larval flies damage animals = ______
Myiasis
Myiasis = _____
Maggot (larval) infection
What is the general lifecycle of bot flies?
Egg--> Larva (maggot) (inside animal)--> Pupa (soil)--> Adult fly (no mouth; Look like bees)
Fly larva can either be _____ parasites (living host) or _____ parasites (living host or dead material).
Obligate; Facultative
What are common names for Cattle bot flies?
Cattle grubs," "heel flies," "warble flies
Cattle bot flies are _____ parasites.
Obligate
What are the 2 species of Cattle bot flies? (differ by larval migration)
1) Hypoderma lineatum (common cattle grub): Larvae to esophagus
2) Hypoderma bovis (northern cattle grub): Larvae to spinal cord
What is the danger of killing the larval stage of cattle bot flies? What should you do to avoid this?
Anaphylactic reaction causes bloat (hypoderma lineatum in esophagus) or neurologic issues (hypoderma bovis in spinal cord);
Treat in November BEFORE larvae migrate to esophagus/spinal cord (January) and AFTER 1st hard frost to kill adult flies
How are cattle bot flies diagnosed?
1) Bot larvae in lumps (warbles) on back (spiracles or breathing apparatus exposed)
2) May see eggs on leg hairs
Adult bot flies are NOT parasites, only the larval stage. (TRUE/FALSE)
True
What are the economic consequences of cattle bot larvae?
1) Damaged hide/meat
2) Decreased weight gain (growth)
3) Predispose to inflammation
4) Worry factor and self trauma
What is the treatment for cattle bot larvae?
Ivermectin type dewormers (Ivermectin, Doramectin, Eprinomectin, Moxidectin); Treat 1st week of November, but NOT after January (larvae death causes problems); Never squeeze larvae out of warble
What is the sheep bot fly called? Where are the larvae found?
Oestrus ovis or Sheep nasal bot fly; Nasal sinuses
Life cycle: Oestrus ovis (Sheep nasal bot fly)
1) "fly by" larvae squirt into nostrils (deposit larvae, NOT eggs)
2) Larvae move into sinuses for winter (1-10 months)
3) When mature, drop onto ground/pupate
4) Adult flies emerge, breed, deposit larvae
How is Oestrus ovis (Sheep nasal bot fly) diagnosed?
Snotty nose, sneezing, larvae in water trough
What is the pathology caused by Oestrus ovis (sheep nasal bot fly)?
Irritation to mucosa (uncomfortable, distracts from grazing)
How is Oestrus ovis (sheep nasal bot fly) controlled?
Ivermectin (PO, SQ; NOT topical) 1st 1-2 weeks in November;
In Northwest, 1 cycle/year (treat 1x/year)
In warmer regions, 2 cycles/year (treat 2x/yr)
What animal parasite can cause human opthalmomyiasis (rare)?
Oestrus ovis (sheep nasal bot fly)
What is the horse bot fly? Which species is most common?
Gasterophilus intestinal or nasalis; Gasterophilus intestinalis
Life cycle: Gasterophilus (Horse bot fly)
1) Eggs laid on foreleg hair (chin)
2) Licked up, larvae hatch in mouth, develop under tongue (1 month)
3) Larvae mature in stomach = Gastric myiasis (squamous epithelium) (8-10 months)
4) Spring/warmer weather, exit via feces into soil/pupate
5) Adults e
What do adult bot flies look like?
Bees (don't bite/sting)
What is the treatment for Gasterophilus (horse bot fly)?
Ivermectin (Moxidectin) 1st 1-2 weeks of November
How are Gasterophilus (horse bot fly) diagnosed?
1) Eggs on legs, chest, face; Worry factor
2) Larvae in stomach (necropsy)
3) Larvae in feces post-deworming;
Infection is often assumed in horses
How can you control Gasterophilus (horse bot fly)?
1) Eliminate eggs on horse: Bot block, comb, scissors, 104 F water (induce exit), insecticides
2) Ivermectin (Moxidectin) after 1st frost (killed flies) in November
What is the pathology caused by Gasterophilus (horse bot fly)?
1) Stomach ulceration
2) Stomatitis (migration in mouth)
3) Often no pathological signs
What is the rodent bot fly?
Cuterebra (Rodent bot fly)
Life cycle: Cuterebra (Rodent bot fly)
1) Fly lays eggs near rodents/cats
2) Hatched larvae stick to fur of rodents/cats
3) Larvae enter through mouth, nose, eye, anus/migrate (don't penetrate intact skin)
4) Warble forms around face/neck (eye rare) in late summer/early fall
5) Usually not pat
In what animals is Cuterebra (rodent bot fly) usually found?
Rodents, cats, dogs, rabbits
How many generations per year are seen in Cuterebra (rodent bot fly)?
1 generation/year
What is the treatment of Cuterebra (rodent bot fly)?
1) Removal
2) Nothing
3) H2O2
4) Prevent with Ivermectin in Spring (if recurrent infections)
What is the difference between Obligate myiasis and Facultative myiasis causing flies? (w/examples)
1) Obligate myiasis: Require specific host; Ex. Screwworms
2) Facultative myiasis: Don't require specific host; Ex. Blowflies
What are other names for Blowflies (1st flies to arrive at a carcass)? Describe their appearance.
Bottle or Calliphorid flies (Lucilla, Calliphora, Phormia); Metallic/colorful
Adult Blowflies (ARE/ARE NOT) parasites (cause damage).
Are not (facultative parasites)
Blowflies cause myiasis in sheep called _____? What breed is most susceptible?
Strike;" Merino sheep
In what animals/conditions is Blowfly myiasis a problem?
1) Sheep with wet, rotting, soiled wool (major)
2) Livestock with wounds, dehorning, castration
3) Long-haired dogs
Life cycle: Blowflies
1) (Adult Phase) Adult flies lay eggs on susceptible part (wound, soiled, etc.) of sheep
2) (Sheep Phase) Larvae eat flesh
3) (Soil Phase) Larvae drop to ground/Pupate/Adult flies emerge
What is the pathogenesis of Blowflies?
1) Larvae secrete proteolytic enzymes that digest/liquefy tissue/enlarge wound
2) Other fly species attracted/lay eggs
3) 2nd bacterial infection
4) Toxins from myiasis lesion absorbed
5) Sheep stop eating, loose condition, die
How are Blowflies controlled in sheep?
1) Sanitation
2) Crutch (remove rump/belly wool) and dock (tail) sheep
3) Internal nematode control
4) Coccidiosis (protozoa) control
5) Insecticides for adult fly control
Describe blowfly strike in outdoor rabbits.
1) Loose stools
2) Old, disabled, overweight
3) Can't self-clean
4) Larvae infest/kill rabbit in a day
Myiasis causing flies: (name the animal)
Hypoderma
Oestrus
Cuterebra
Gastrophilus
Blowflies
Screwworms
Hypoderma: Cattle
Oestrus: Sheep
Cuterebra: Rodents, cats, dog
Gastrophilus: Horse
Blowflies: Sheep, dirty animals (dead tissue)
Screwworms: Extirpated (mostly)
What is one reportable blowfly Myiasis? What are the 2 species?
Screwworm;
1) Cochliomyia
2) Hominovorax
What type of tissue do Screwworm Myiasis (Cochliomyia, Hominovorax) eat?
Living tissue
Life cycle: Screwworm
1) Adult female attracted to open, clean wound/lay eggs
2) Eggs hatch in hours/burrow in wound (attract more flies)
3) Larvae feed for 1 week/Fall off and pupate
4) Adult flys emerge (7 days later)
Screwworm flies are attracted to ______.
Fresh wounds/bites
Describe Screwworm Myiasis.
Adult flies lay eggs on fresh wound; Larvae feed on healthy tissue of wound; Secondary blowfly strike/bacterial infection/death
How are Screwworms controlled?
Male fly sterilization program (3 life cycles after last detection);
Female only mate once mated with sterile male�> non-viable offspring (current barrier in panama)
Where was the last Screwworm infestation in the US? What animals did it mainly affect?
Florida Keys; Key deer
If you were working with a control program to prevent the spread of Screwworms (Cochliomyia) off the Keys and into mainland Florida, what life cycle stage(s) would you worry about?
1) Larvae on host (check animals)
2) Adult flies (can't control)
What type of fly maggot is NEVER a parasite? Where is it found?
Eristalis or Rat-tailed Maggot ("mousies"); Stagnant, high organic content water (sewage lagoons, cesspools)