MODULE 6: Myiasis Flies (Family Calliphoridae)

What are myiasis flies?

Dipterous insects whose larvae invade tissues or organs of humans and animals, causing myiasis

What is myiasis?

Infestation of the skin by developing larvae or maggots of various fly species within the order Diptera

What does the Greek word myia mean?

Fly

Which fly is called the human botfly?

Dermatobia hominis

Which fly is called the tumbu fly?

Cordylobia anthropophaga

What factors influence the medical conditions caused by myiasis?

Body location and relationship of the larvae with the host

What are the economic effects of myiasis on animal farming?

Reduced milk production, weight and fertility issues, reduced hide quality, economic losses

Where does human myiasis occur worldwide, and where are species more abundant?

Worldwide, with more species and greater abundance in poor socioeconomic regions of tropical and subtropical countries

What rank may myiasis have among travel-associated skin diseases in non-endemic countries?

Fourth most common

What determines the classification of myiasis based on fly reproductive habits?

Ovipositioning and larvipositioning habits

What is accidental myiasis?

Myiasis usually acquired accidentally by ingestion of eggs or larvae with contaminated feed or water

Where are eggs or larvae deposited in accidental myiasis?

Manure or decaying organic matter, garbage, carcasses

Where may eggs be deposited before larvae migrate to the rectum, intestine, or vagina?

Around the anus or vulva

Where do larvae migrate after hatching from eggs deposited around the anus?

Rectum or intestine

Where do larvae migrate after hatching from eggs deposited around the vulva?

Vagina

Which blue bottle fly genus is involved in accidental myiasis?

Calliphora sp.

Which green bottle fly genus is involved in accidental myiasis?

Lucilia sp.

Which flesh fly genus is involved in accidental myiasis?

Sarcophaga sp.

Which housefly genus is involved in accidental myiasis?

Musca sp.

What is specific or obligate myiasis?

Myiasis in which eggs or larvae are deposited in or near living tissues or organs and larvae inevitably become parasitic

Which screw worm fly genera cause specific or obligate myiasis?

Callitroga sp. and Chrysomyia sp.

Which bot fly genus causes specific or obligate myiasis?

Gasterophilus sp.

Which warble fly genus causes specific or obligate myiasis?

Hypoderma sp.

What is semi-obligate myiasis?

Myiasis in which eggs and larvae are deposited in decaying organic matter and less frequently in diseased tissues and neglected wounds

Which flesh fly genus is involved in semi-obligate myiasis?

Sarcophaga sp.

Which green bottle fly genus is involved in semi-obligate myiasis?

Lucilia sp.

Which blue bottle fly genus is involved in semi-obligate myiasis?

Calliphora sp.

Which black blow fly genus is involved in semi-obligate myiasis?

Phormia sp.

What is cutaneous myiasis?

Myiasis affecting the skin

What is ocular myiasis?

Myiasis affecting the eyes

What is aural myiasis?

Myiasis affecting the ears

What is gastric myiasis?

Myiasis affecting the stomach

What is intestinal myiasis?

Myiasis affecting the intestine

What is vaginal myiasis?

Myiasis affecting the vagina

What is nasal myiasis?

Myiasis affecting the nose

What is scrotal myiasis?

Myiasis affecting the scrotum

What is rectal myiasis?

Myiasis affecting the rectum

Which four important families include myiasis flies?

Calliphoridae, Sacrophagidae, Oestridae, Cuterebridae

Which genus of Calliphoridae is called the blue bottle fly?

Calliphora

Which genus of Calliphoridae is called the green or copper bottle fly?

Lucilia

Which genus of Calliphoridae is called the black blow fly?

Phormia

Which genus of Calliphoridae is called the screw worm fly?

Chrysomyia

Which genus of Calliphoridae is associated with primary and secondary screw worm flies?

Callitroga

Which genus of Calliphoridae is called the skin maggot fly?

Cordylobia

Which genus of Calliphoridae is called the foot maggot fly?

Booponus

What is the common name of Calliphora vomitoria?

Blue bottle fly

What is another species listed under Calliphora?

C. erythrocephala

What is the body color of Calliphora vomitoria?

Metallic blue

What is the approximate body length of Calliphora vomitoria?

12 mm

What is the eye color of Calliphora vomitoria?

Red

What type of hairs are present on the squama of Calliphora vomitoria?

Short and long hairs

Which species of Lucilia affects sheep in 🇦🇺 Australia?

Lucilia cuprina/caesar

Which Lucilia species affects sheep in the 🇺🇸 United States?

L. sericata

What is the body color of Lucilia cuprina and Lucilia caesar?

Metallic coppery green

What type of hairs are present on the squama of Lucilia?

Short hairs only

What is the eye color of Lucilia?

Brownish red

What is the body length of Lucilia?

8–10 mm

What is the body color of Phormia regina?

Black with a metallic blue-green sheen

What is another species listed under Phormia?

P. terrae-novae

What condition do the maggots of Calliphora, Lucilia, and Phormia produce in sheep?

Blowfly strike

How many eggs are laid in clustered batches by Calliphorine flies?

50–150

How many eggs may Calliphorine flies lay during their lifetime?

3,000–5,000

How long do Calliphorine fly eggs take to hatch?

8 hours to 3 days

What are the larvae of Calliphorine flies like?

Segmented, wormlike, mobile, apodous

How many times do Calliphorine fly larvae molt before becoming fully grown maggots?

Twice

How long does it take Calliphorine fly larvae to become fully grown maggots?

2–19 days

How long is the prepupal period of Calliphorine flies?

2–7 days

Where do mature Calliphorine fly larvae pupate?

On the ground after leaving the host or carcass

How long does the pupal stage of Calliphorine flies last?

3–7 days

How long does the complete Calliphorine fly life cycle take?

2–5 weeks

What is the adult Calliphorine fly life span?

1 month or longer

How many generations of Calliphorine flies may be completed in a year?

9–10 generations

What attracts blowflies to animals?

Wounds on the skin

Where do blowflies lay their eggs on sheep?

Wool

What do blowfly maggots secrete to digest and liquefy host tissues?

Proteolytic enzymes

How do blowfly maggots feed on host tissues?

They digest and liquefy tissues with proteolytic enzymes and then feed on them

What attracts additional flies to a blowfly-infested wound?

Foul smell

How do blowfly larval movements affect the animal's feeding and condition?

Cause irritation, poor feeding, emaciation, and weakness, reducing meat and milk yield

What may complicate blowfly larval burrowing into the skin?

Secondary bacterial infection

What severe systemic conditions may cause death in animals with blowfly strike?

Toxemia or septicemia

How does blowfly strike affect fleece value?

Reduces the value of the fleece

How is blowfly strike treated by removing wool and larvae?

Clip wool and surgically remove the larvae

What topical treatment is listed for blowfly strike?

Low concentration dressing compounds

What additional treatments are used for blowfly strike?

Dip or spray with insecticides

What is the primary screw worm fly?

Callitroga (Cochliomyia) hominivorax

What is the secondary screw worm fly?

C. macellaria

What is the body color of Callitroga hominivorax?

Bluish green

How many longitudinal stripes are on the thorax of Callitroga hominivorax?

3

Where does Callitroga hominivorax lay its eggs?

At the edge of the wound or on the carcass

How long does it take for an adult Callitroga hominivorax to form?

3–7 days

What weather condition predisposes animals to screw worm infection?

Rainy weather

How do screw worm larvae affect host tissues and lesions?

Penetrate and liquefy tissues and considerably extend lesions

What is the main effect of screw worm infestation on animals?

Reduced production as animals become weak and restless

How are wounds treated in screw worm infestation?

Thoroughly clean wounds and dress them with appropriate antiseptics

What should be done to screw worm larvae during treatment?

Destroy the larvae

What is the common name of Chrysomya bezziania?

Bluish green fly

Where is Chrysomya bezziania particularly important in the Philippines?

Negros and Panay islands

What are the maggots of Callitroga and Chrysomya commonly called?

Screw worms

Which hosts can Chrysomya bezziania attack?

Humans and animals

How many eggs does Chrysomya bezziania lay in a cluster?

150–300