Diptera- Myasis Flies Flashcards
(90 cards)
1
Q
What year was the term myiasis first used?
A
1840 with dipterous larvae infecting humans
2
Q
In what species do myiasis flies present economic issues?
A
- Sheep and cattle- Production loss cost to producers
- Significant problem in pet rabbits
3
Q
Maggot therapy is used in which group of flies?
A
Myiasis flies
4
Q
What is the definition of myiasis?
A
Infestation of living vertebrate animals with dipteran larvae, feeding on the hosts dead or living tissue
5
Q
What 3 areas of the body are usually affected by myiasis flies?
A
- Wounds on skin
- Body cavities such as nasal sinuses
- Natural tracts such as GIT
6
Q
How are myiasis flies classified?
A
According to their parasitic relationship with the host
7
Q
What are the 3 families of myiasis flies?
A
Diptera -> Cyclorrhapha ->
- Calliphoridae (blow flies)
- Oestridae (bat/warbleflies)
- Sarcophagidae (flesh flies)
8
Q
What does it mean for a myiasis fly to be an obligate parasite?
A
Larvae require living host for development
9
Q
Which 2 families of myiasis flies are obligate parasites?
obligate- requires living host for development
A
Oestridae
+
Calliphoridae (specifically new world screwworm)
Diptera -> Cyclorrhapha -> Oestridae
10
Q
What are the 3 genera to know within the oestridae family that are obligate parasites?
A
- Gasterophilus (stomach bots in horses)
- Oestrus (nasal bots in sheep)
- Hypoderma (cattle grubs/warble flies)
11
Q
Obligate parasites of the myiasis fly group are ____________ host specific.
A
Relatively
12
Q
Which genera of the calliphoridae family are obligate parasites?
A
Cochliomyia hominivorax (new world screwworm)
13
Q
Describe facultative parasites of the myiasis fly group.
A
- adults are attracted to foul aromas, caused by wounds or areas soiled by feces
- larvae feed on necrotic tissue
14
Q
Facultative parasites of the myiasis fly group have a _____________ host range.
A
Broad
15
Q
Facultative parasites of the myiasis fly group are important for what branch of entomology?
A
Forensics: the use of insects in death investigations
16
Q
Describe accidental parasitism of myiasis flies.
A
Larvae are ingested accidentally and found in the GIT
17
Q
Which family of Cyclorrhapha causes fly/blowfly strike?
A
Calliphoridae
18
Q
The calliphoridae family affects mainly which hosts?
A
Mainly sheep, but in recent years has become an increasing problem in pet rabbits
19
Q
Where is the calliphoridae family found?
A
North America
20
Q
What are the 5 specific genera of flies to know within the calliphoridae family?
A
- Lucilia spp (greenbottles)
- Phormia regina (blackbottles)
- Calliphora spp (bluebottles)
- Cochliomyia macellaria (secondary screwworm)
- Chrysomya rufifacies (hairy maggot blow fly)
21
Q
What are the general characteristics of ‘blowflies’?
A
- Medium sized adults
- Metallic blue, black, or green sheen
Diptera -> Cyclorrhapha -> Calliphoridae
22
Q
Where do female myasis flies lay eggs?
A
On wounds, soiled fleece, or dead animals
23
Q
How long do Calliphoridae fly eggs take to hatch?
A
12 hours
24
Q
How many myasis fly larval stages are there and how long does it take them to mature?
A
L1-L3 (3 stages)
takes 3-10 days to mature as they feed on wounds/dead tissue
25
Myiasis flies can overwinter in what stage?
Pupae
- if the soil temperature is less than 15°C
26
Where are myiasis fly pupae found?
On the ground
27
Adult myiasis flies emerge from pupae after about how long?
3-7 days
28
What do adult myiasis flies feed on?
Protein meal
29
How long do adult myiasis flies live and how many eggs do they lay?
Live for about 30 days and lay about 3000 eggs in that time (batches of 100-200)
30
When are adult myiasis flies most commonly found?
May/June - September
31
What do primary myiasis flies do?
- Initiate a strike on a living animal
- Larvae can penetrate intact skin
32
Which myiasis fly genus are primary flies?
Lucillia spp (green bottleflies)
33
What do secondary myiasis flies do?
- Feed on dead/decaying flesh
- Cannot initiate, but attack area already struck and extends the area of damage
34
Which myiasis flies are secondary flies?
Some Phormia spp (blackbottle) and Calliphora spp (bluebottle)
35
What do tertiary myiasis flies do?
Feed on dried lesions when the host is near death
36
Which myiasis flies are tertiary flies?
Sarcophaga and Wohlfahrtia (flesh flies)
37
What are some predisposing factors that attract myiasis flies?
- Ammonia, sulphur, or volatile organic acids (produced by bacteria in skin wounds)
- Wool rot caused by high temperature and humidity
- Soiled fleece by urine or feces
- Wounds from castration, shearing, or dehorning
38
How do myiasis flies cause severe skin damage of the host?
- Primary blowfly larvae lacerate skin with oral hooks
- Secrete proteolytic enzymes that digest and liquify tissue
- Cause inflammatory reactions
- Secondary blowfly attacks extend and deepen the lesion
39
How do myiasis flies lead to production losses?
- Restlessness from irritation and distress
- anorexia
- loose condition (diarrhea)
- Death by septicemia in severe cases
40
What is the mortality rate in myiasis fly attacks?
10%
41
Where are new world screwworms found geographically?
Tropical and subtropical areas of the Americas
42
Describe the appearance of the new world screwworm.
Metallic green to bluish green, 3 distinct horizontal stripes on thorax
43
What are the hosts of new world screwworms and what do they larvae feed on?
All warm blooded animals, but especially cattle and sheep
the larvae need to feed on their living tissue, described as 'eating the host alive'
44
Where has the new world screwworm been eradicated from?
USA, Mexico, and most of Central America
45
What are the characteristics of the family oestridae?
- Large hairy flies called bot flies
- Mostly host specific
- Larvae are obligatory parasites of large mammals, but the adults do not feed and have either no or vestigial mouthparts
46
What are the 3 genera/genus of importance in the family oestridae?
- Hypoderma- warble fly
- Oestrus- nasal bot of sheep
- Gasterophilus- nasal bot of sheep
47
What is the species of importance within the genus Oestrus of the Oestridae family?
Oestrus ovis: 'nasal bot' of sheep
48
What are the characteristics of oestrus ovis?
- Grey fly with black spots on abdomen
- Covered in short brown hairs
- Rudimentary mouthparts
| looks like an alien
49
Are oestrus ovis flies oviparous or viviparous?
Viviparous; L1 around nostrils and matures in the nasal sinuses of the sheep
50
Most oestrus ovis infections are __________, but rare heavier ones result in ____________.
Light; unthriftiness (poor body condition, weight loss)
51
Where do oestrus ovis larvae attach and feed?
Attach to nasal mucosa and feed on secretions
52
When would an infestation by oestrus ovis cause neurological signs?
If larvae get trapped and die in the sinuses, secondary bacterial infection can result with cerebral involvement, called 'false gid'
## Footnote
false gid- symptoms are similar to that of a brain tapeworm. Tapeworm is known as 'true gid'
53
Excess mucous production caused by an oestrus ovis infestation can lead to increased susceptibility to what?
Pasturella spp
| causes pneumonnia in sheep
54
How do the adult oestrus ovis flies affect animals?
- Fly worry
- Restlessness/panic
- Lowered food conversion and lighter carcasses
55
Can oestrus ovis infect humans and if so, how?
Yes, occasionally; larvae are deposited around the eyes or lips
56
What are the characteristics of the gasterophilidae genus of the oestridae family?
- Horse bots
- Large, robust dark flies
- Body covered in yellowish hair
- Rudimentary mouthparts
57
Where do gasterophilidae develop?
In the stomach of equines; usually considered to be pathogenic
58
What are the 3 important species of the gasterophilidae genus?
- Gasterophilus intestinalis
- G. nasalis
- G. haemorrhoidalis
59
Do adult gasterophilus flies feed?
No- they have rudimentary mouthparts
60
Where do the eggs of horse bots, throat bots, and nose bots attach?
- Horse bot fly: hair of inner forelegs
- Throat bot fly: in batches under the jaw
- Nose bot fly: hair of upper and lower lip
61
How many generations of gasterophilus flies do we see per year?
A single one
62
Where do the bots (larvae) of G. intestinalis and G. nasalis attach?
- Intestinalis: cardiac region
- Nasalis: pylorus and duodenum
63
When are adult gasterophilus flies most active?
June-August
64
Describe the veterinary importance of gasterophilus flies.
- Larvae can cause stomatitis in the buccal cavity or local inflammation in the stomach, but generally, horses do not appear to suffer any ill effects
- Owners often insist on treatment especially if larvae are seen in feces, which does reduce the adult population and fly worry
65
What is the common name of the genus hypoderma of the family oestridae?
- 'Warble flies' and 'cattle grubs'
- Heel flies/gadflies
66
What are the two important species of the hypoderma genus?
- H. lineatum
- H. bovis
67
Describe the appearance of Hypoderma flies.
- Resemble bees
- Orange-yellow hairs on abdomen with a broad band of black hairs around the middle
- Rudimentary mouthparts
68
Where are hypoderma flies found geographically?
North America, northern Mexico to northern Canada, with the exception of south Texas and Alaska
69
Where do the eggs of H. bovis and H. lineatum attach?
H. bovis singularly on the lower parts of the body and on the legs above the hocks; H. lineatum in rows of 6 or more on individual hairs below the hocks
70
What happens once hypoderma eggs hatch?
Larvae burrow into the skin and travel subcutaneously to developing place
71
Where do larvae of H. lineatum and H. bovis develop?
- H. lineatum in CT of esophagus
- H. bovis tissue surrounding spinal column
- Fully developed L3 of both: subcutaneously on back
72
Where do larvae of hypoderma flies overwinter?
Inside the host
73
How do the hypoderma adult flies affect the host?
- Animals try to escape: 'gadding'
- Injury and lowered food conversion
74
Inflammation (warbles) around the traveling hypoderma larva can cause what?
Secondary bacterial infections
75
What can happen if either H. bovis or H. lineatum larvae die in the host during development?
- H. bovis in the spinal canal: paraplegia
- H. lineatum may result in bloat
76
Hypersensitivity responses due to hypoderma spp may be associated with what?
Rupture of larvae
77
How can the migration of the hypoderma spp in horses affect them?
Can make wearing a saddle or harness difficult in the region of the back
78
Holes in the skin caused by the hypoderma larvae lead to production losses how?
Carcass and hide depreciation
79
Describe the appearance of the subfamily cuterebrinae.
- Large hairy flies
- Flies have blue to black colored abdomen
- Adults do not feed and have no or only vestigial mouthparts
| Diptera -> Cyclorrhapha -> Oestridae -> Cuterebrinae
80
What are the two genera of importance within the subfamily Cuterebrinae?
- Cuterebra spp
- Dermatobia hominis
81
Where are cuterebra spp found and what animals do they infest?
Found in the western hemisphere, throughout the Americas; parasites of rodents, rabbits, dogs, and cats
82
How are the eggs laid and hatched in the cuterebra spp?
| parasites of rodents, rabbits, dogs, and cats
Eggs laid around burrows, and, as the host brushes past the eggs they hatch and larvae attach to the host and enter the body to migrate to specific sites
83
Where are Dermatobia hominis found and what animals do they infest?
Found in Mexico and Central and South America; infect humans, larger mammals, and birds
84
How are the eggs laid and hatched in Dermatobia hominis?
Eggs attach to blood sucking flies such as mosquitoes and when they feed, the eggs hatch onto host and penetrate the skin
85
Describe the appearance of the adult flies of the sarcophagidae family.
Dorsal surface of the thorax is marked with three longitudinal bands, while the dorsal surface of the abdomen exhibits three, well-defined rows of oval black spots which are confluent with one another
86
What is the common name of organisms in the sarcophagidae family?
Flesh flies
87
Where are the sarcophagidae family found and what hosts do they infect?
- Found in southern Canada and the northern part of the USA
- They attack rabbits, dogs, cats, minks, and foxes (sometimes humans)
88
Are sarcophagidae oviparous or viviparous?
Viviparous: produce larvae onto wounds or body openings such as genitals
89
Where does pupation of the sarcophagidae family occur?
Soil
90
What are the two species of importance within the sarcophagidae family?
- Wohlfahrtia vigil
- Sarcophaga haemorrhoidalis
