FLIES PRODUCING MYIASIS Flashcards
1
Q
Myiasis
A
infestation of living tissue by fly larvae
2
Q
Where can myiasis be?
A
skin
body cavities
organs
etc.
depends on type of myiasis
3
Q
Facultative myiasis
A
diptera whose larvae typically develop in decomposing organic matter
BUT
will occasionally invade necrotic tissues of living animals
4
Q
What does forensic entomology help with in the sense of post-mortem intervals?
A
knowing the length of time required for maggots to complete their development under specific environmental conditions allows us to determine how long a body has been dead
5
Q
What is an example of a facultative myiasis?
A
wool maggots/fleece worms
minor problem in Western Hemisphere
6
Q
Wool maggots =
A
fleece worms
7
Q
What do wool maggots do?
A
invade existing wounds (weeping sores) or areas that are wet such as soiled wool around anus
8
Q
Do wool maggots consume living tissue?
A
NO
9
Q
What fly larvae are wool maggots?
A
Calliphoridae (blow fly)
10
Q
In North America, what are the two most important wool maggot species?
A
black blow fly
green bottle fly
11
Q
In Australia, what fly produces fly strike?
A
bronze bottle fly
wool maggots infest portions of body with damp, soiled wool
12
Q
Fly strike (calliphoridae)
A
infestation by wool maggots (fleece worms)
13
Q
How does sloughing occur due to a fly strike?
A
maggots grazing on bacteria, exudates, and necrotic material at base of hair weakens the hair so that it sloughs off causing shedding of large areas of wool
14
Q
Obligatory myiasis
A
these species of diptera having larvae which NORMALLY develop in or on the body of living vertebrate
15
Q
In obligatory myiasis, where must immature stages develop?
A
immature stages MUST develop in a vertebrate host
16
Q
What has obligatory myiasis of the digestive tract?
A
gasterophillinae
17
Q
What has obligatory myiasis of the nasopharyngeal cavities and other internal respiratory systems?
A
oestrinae
18
Q
What has obligatory myiasis of the dermic or subdermic?
A
hypodermatinae
and
cuterebrinae
19
Q
What has obligatory myiasis of wounds?
A
cochliomyia hominiyorax (calliphoridae)
20
Q
The primary screwworm, Cochliomyia hominivorax, is in what family? What is significant?
A
calliphoridae
ONLY one in calliphoridae
21
Q
Gasterophilinae, Oestrinae, Hypodermatinae, and Cuterebrinae are all subfamilies of what?
A
of the family Oestridae
22
Q
What does the ending -inae signify?
A
subfamily
23
Q
What are common characteristics of oestrid flies?
A
1) robust larvae known as “bots” or “grubs” (all obligate parasites)
2) 1st installs enter host, molt twice, spend entire larval life inside host as parasite
3) late third instars leave host to pupate in soil
4) adults are bee-like with reduced mouthparts and DO NOT FEED
24
Q
How do oestrid flies feed?
A
THEY DO NOT FEED they have reduced mouthparts
-vestigial mouthparts
-atrophied mouthparts
-non-functional mouthparts
25
Because adult oestrid flies cannot feed, what do they do?
they are dependent on nutrient stores acquired as larvae
they have limited time as adults to reproduce
26
True or False:
All subfamilies have examples of human myiasis.
TRUE
they can be irritating if first instars infest us, BUT they cannot successfully develop in a human due to our immune systems
27
What does human myiasis produce?
itching
irritation
nodules
allergic reactions
28
Gasterophilinae (subfamily)
common horse bot fly
digestive tract
29
Common Horse Bot Fly
(digestive tract)
gasterophilinae (subfamily)
30
Where does a Gasterophilus female oviposit?
on the horse's front legs (eggs are glued to hairs)
31
How do the gasterophilus eggs hatch from the horse front legs?
the horse licks its legs, moisture and warmth from tongue stimulate egg hatch, they get on the tongue and are drawn into the mouth where they detach and crawl into dental interstices
32
Where is a 'pus pocket' formed in the equine?
pus pocket formed in equine gym as first install larvae begin migration
33
What does the pus pocket in the equine result in? What does this interfere with?
irritation and pain
this may interfere with horse feeding
34
What does the first instar larvae of the gasterophilus do?
remains in the gums for a few days then swallowed and molts to the second instar
35
What does the second instar larvae of the gasterophilus do?
attaches to the stomach lining and overwinters there, growing and molting into the third instar
36
Where does the larvae of gasterophilus overwinter?
in the stomach lining
37
What happens when the gasterophilus larvae grows and molts into the third instar in the stomach lining? When?
in the spring the larva detaches from the stomach lining and is carried through the intestinal tract and expelled with feces
38
How does the gasterophilus larvae escape from within the horse?
through being pooped out
39
What happens once the larvae of gasterophilus is expelled with feces?
immediately burrows into the ground, pupates, and emerges as an adult fly about three weeks later
40
Typically how long does the gasterophilus larvae stay burrowing in the ground?
3 weeks then emerges as an adult fly
41
What do adult gasterophilus feed on?
THEY DO NOT FEED
rely on stored nutrients to survive for the week or two during which they find a mate and the females locate a host and oviposit there on
42
In short terms, what is the gasterophilus life cycle?
1) adult fly lays eggs on hairs of horse legs
2) horse licks legs, eggs hatch, larvae are on tongue where they form pus pockets in horse mouth
3) after first instar molts to the second instar it is swallowed into the stomach lining
4) attaches to stomach lining and the bots stay there for 8 to 10 months molting to third instar
5) once at the third instar it goes through the gastro tract and is pooped out
6) immediately it burrows and stays there for about 3 weeks
7) once adult fly emerges it comes from out of the ground
8) then the adult fly mates (IT DOES NOT FEED IT USES STORED NUTRIENTS)
9) female lays eggs once again and cycle continues
43
What has obligatory myiasis of the nasopharyngeal cavities and other internal respiratory systems?
subfamily oestrinae
examples:
oestrus ovis (sheep nose bot)
deer nasal bot
44
Do oestrinae larviposit or oviposit?
they are larviparous
45
What are symptoms of an animal having oestrus ovis?
nasal discharge
nasal sinuses
46
What is the life cycle of the sheep nasal bot (oestrus ovis)?
1) female larviposits larvae
2) fly lands on sheep and larvae is flung out of her body into sheep's nostril
3) larvae crawl through nasal passage and lodge in supraorbital sinuses
4) larvae overwinter and grow there
5) migrate back down nasal passage in spring
6) once they are large and nasal passage is tight, sheep will sneeze propelling larvae out
7) larvae fall to ground, burrow in soil, pupate, emerge as adult flies
8) ADULT FLY DOES NOT FEED (rely on stored nutrients)
9) mate and life cycle repeats
47
What is a warble?
furuncle created by Hypodermic larva on cow's back
the host tissue surrounds larva and forms the capsule called the warble
48
What are the two subfamilies of obligatory myiasis that is dermic or subdermic?
Hypodermatinae
Cuterebrinae
49
50
Hypodermatinae
cattle grub
51
Cattle grub
Hypodermatinae
52
Where does the Hypodermatinae grub grow?
inside cow where tissue grows around the grub forming furuncle where the grub grows just under the skin
53
When are bot fly/hypoderma acquiring food?
as larvae inside the host getting nutrition
DO NOT FEED AS ADULTS
54
What might an adult cattle grub fly look like?
fuzzy
bee-like appearance
55
What is the life cycle of Hypoderma spp.?
1) female glues eggs onto cow hair
2) neonate larva burrows through skin to subcutaneous tissue
3) larva settles in and host tissue begins to grow around producing a furuncle (warble)
4) within the warble the larva grow and overwinter
5) when spring comes, mature larva emerge through the breathing hole they cut in the warble
6) fall to the ground, burrow in soil, pupate
7) a few weeks later emerges, mates, female flies look for host and oviposit
8) ADULTS DO NOT FEED
56
What are other warbles produced by?
there aren't any
only furuncle produced by Hypoderma is called a warble
57
What does the main damage to cattle with Hypoderma?
main damage from adult cattle grub flies is produced when they frighten the cow as they approach to oviposit
gadding: cows bolt running headlong to get away from fly which can cause them to run into objects or off cliffs
58
Why is it slightly odd cows become greatly frightened by adult cattle grub flies?
adults don't have mouthparts so they cannot bite or sting
59
Gadding
cows bolt running headlong to get away from flies
60
Why are cattle grub flies negative when it comes to us humans eating cow?
consumers do not want to eat cattle grubs where the warbles were formed
warble must be cut out of carcass
results in much wasted food (meat trimming)
it's perfectly fine to eat it's just not appealing to the eye so consumers won't buy
61
What negative damage do cow grub flies do to leather?
warble holes cut in hide never fully heal
scars and openings are formed in hide creating damage to leather
62
Do adult bot flies bite or sting
NO NO NO THEY HAVE NO MOUTHPARTS
63
Do cattle grubs make meat unhealthy for human consumption?
NO NO NO
perfectly fine to eat, but unappealing so people won't buy and eat
64
Subfamily Cuterebrinae
Cuterebra
Dermatobia hominis
65
Cuterebra
Subfamily Cuterebrinae
66
Dermatobia hominis
Subfamily Cuterebrinae
67
What does Cuterebra spp. effect?
rodent
squirrel
rabbit
68
What does dermatobia hominis effect?
human bot fly
69
Where is the dermatobia hominis?
South American species with wide host range
70
What does the adult cuterebra look like?
robust
fuzzy
bee-like
71
Since cuterebra spp. is found in rodents it is pretty small.
T or F
FALSE
they are disproportionately large compared to host
72
What is a wolf?
swellings under skin from bots
73
Other than rodents, what can cuterebra spp. use as a host?
sometimes dogs and cats
74
Can cuterebra develop in cats and dogs?
NO they cannot successfully develop in cats or dogs
75
If they can't develop, what negative effect do cuterebra have on cats and dogs?
can produce damage
-nerve damage
76
How should you remove larva from cats and dogs? What should you NOT do? Why?
NOT FROM PRESSURE THIS COULD MAKE LARVA RUPTURE PRODUCING ANAPHYLACTIC SHOCK
wound should be surgically enlarged, light pressure applied to extrude larva intact
77
What do dermatobia hominis eggs attach to?
body of zoophilous flies or mosquitoes (phoretic vectors)
78
Dermatobia hominis
human bot fly
79
human bot fly
Dermatobia hominis
80
Why are the vectors that dermatobia hominis pick efficient?
the vectors are attracted to animals which ensures Dermatobia ends up on appropriate host
81
What does phoresy mean? Why is this of significance?
hitchhiking
eggs of dermatobia hitchhike on flying insects as they seek hosts
82
What do female dermatobia do with her eggs?
glue them to the body of a flying insect, insect finds host, bot fly larvae hatch and burrow into host skin
83
What is dermatobia host preference due to?
due to vector (since it is hitchhiking)
84
Is dermatobia hominis host specific?
NO
wide range of potential hosts, especially cattle, but also found in wild and domestic mammalian hosts INCLUDING HUMANS
85
What is dermatobia hominis subfamily?
Cuterebrinae
86
Where is dermatobia hominis (human bot fly) common?
from Mexico through much of South America
87
What could be a description of dermatobia hominy host?
almost any warm-blooded animal
humans common
88
Since dermatobia hominis are noisy in flight, what is their strategy for delivering eggs?
catches bloodsucking insects, attaches eggs to its abdomen with operculum oriented downward
89
How many species of flies have been recorded as carriers for dermatobia hominis eggs?
at least 48
90
What happens when a carrier of dermatobia hominis egg lands to feed?
warmth of skin stimulates larvae to hatch, enters unbroken skin, develops without migrating, develops about 6 weeks, mature larva emerges, drops to soil, pupates in soil, emerges as adult
91
What does dermatobia hominis cause on its host?
painful lesions, if on scalp it can swell to a large size
92
How long do dermatobia hominis develop in host?
development requires about 6 weeks
93
How big is mature larva of dermatobia hominis?
pretty large
about the size of top joint of thumb
94
How can you remove dermatobia hominis?
surgically
95
Cochliomyia hominivorax
New world screwworm fly
96
New world screwworm fly
Cochliomyia hominivorax
97
What is Cochliomyia hominivorax (new world screwworm fly) dependent on?
living tissues of live animals in the Americas (wounds)
98
How was the new world screwworm (Cochliomyia hominivorax) eradicated from North America?
the sterile insect technique over 30 years ago
99
Where is cochliyomyia hominivorax (screwworm) still common?
South America
100
What happened with the screwworm in 2016? Did it only affect one wildlife?
showed up in the Florida keys
killed a third of the key deer population, a group of endangered deer found only in keys
affected other wildlife, but endangered species of the key deer received more attention...since they are endangered
101
What does screwworm damage make deer do?
disoriented
staggering
102
What was the nickname of deer infested with screwworm? Why?
zombie deer
staggering, disoriented
103
Why is the screwworm so gruesome in the deer shown in class?
body fluids are draining from the head where screwworm larvae have eaten through the skin and skull invading the brain
104
Unless treated by humans, what happened to the deer affected with screwworm?
they died
without treatment of screwworm it's infestation is fatal
105
What family is cochliomyia hominivorax (screwworm) in?
Calliphoridae (blow flies)
106
Why are screwworms called screwworms?
spiral screw shaped larvae
107
How can a human have their oral cavity infested by screwworm larvae?
people who sleep outside with their mouths open
think of an alcoholic or drug addict in somnolent condition
immediately burrow into gums consuming tissue
108
Is cochliomyia hominivorax common in Hyman oral cavity?
not common, but can happen
109
How do you remove screwworm from human oral cavity?
manually extract (only use chemicals as anesthetic to reduce pain)
ensure all larvae is accounted for (don't want escape and another person infested) and examined for identification
110
What does an adult cochliomyia hominivorax look like?
your typical calliphoridae
shiny blue body
many calliphoridae look at this so identification of larvae is important
111
Can antibiotics be used on cochliomyia hominivorax (screwworm)?
NOPE ineffectual
112
What is the life cycle of the new world screwworm (cochliomyia hominivorax)?
1) female screwworm flies attracted to aroma produced by open wound (even tiny ones)
2) oviposits up to 200 eggs along wound
3) when larvae hatch they immediately burrow into wound and consume living tissue
4) once larval development completed, falls from wound to ground, burrows in soil, forms puparium, pupates
5) several days later adult fly has formed inside puparium, pops off end, emerges, crawls through soil
6) wings dry, fly flies, finds mate
7) female seeks vertebrate host, oviposits
113
Can screwworms feed on dead tissue?
NO ONLY LIVING TISSUE
114
How do screwworm larvae feed?
head down with spiracles (in rear end) sticking up above surface so they can breathe through spiracles while feeding
115
What animal husbandry practices contributed to screwworm infestation?
dehorning and castration
creates wounds making animal vulnerable to screwworms
116
Prior to eradication, what happened to almost every newborn mammal?
had to have screwworm larvae removed from naval
newborn mammals were a prime site for infestation
117
What happened to any animal untreated for screwworm? Why is this not true for humans?
inevitably death
we have thumbs lol we can remove
118
What were some tarry materials marketed for avoiding screwworm? Why wasn't this as effective?
treat naval and physically prevent access by ovipositing female fly
had to handle animals for these tactics, not always possible for range animals
119
What was the sterile insect technique to eradicate screwworm?
male flies from colony were sterilized using radiation
millions of sterile males were released by air over screwworm infested areas
wild female screwworms mate with sterile males, becoming refractory to further mating
120
In this sense, what does sterilization refer to?
reproductive sterility
not elimination of microorganisms
121
How many times does a female screwworm fly mate in their life? What does this mean for the sterile technique?
ONLY ONCE
she is refractory after mating, so if she mates with a sterile male then no screwworm larvae will be produced from her
122
How many eggs can a female screwworm fly oviposit?
up to 200 eggs
123
Where all has the screwworm been eradicated?
through the:
US
throughout Mexico
Central America to Panama
124
Where is the exclusion zone of screwworms currently? Why is this effective?
maintained at the Darien gap (narrow portion of Panama)
small and narrow easier to control
125
Why does the risk of reinfestation of screwworms in North America continue?
South America still has primary screwworms
126
Screwworms were responsible for how many deaths of endangered key deer?
133 deaths in only three months out of fewer than 1,000 individuals
127
Do you have to report screwworms?
YES reportable animal disease
DO NOT LET ANY LARVAE ESCAPE
128
What does an adult cochilomyia hominivorax look like?
typical shiny blue blowfly
129
Tumbu fly
parasite of large mammals
130
Where is the tumbu fly found?
in East and Central Africa
131
Where do female tumbu flies lay their eggs?
in sandy soil (or damp clothing, drying outdoors)
132
What happens after tumbu fly eggs hatch?
larvae seeks a host and burrows into skin
133
How long do larval tumbu fly instars require?
8 to 12 days
134
What does the host of tumbu fly larvae develop? Where?
boil-like sores
usually on the arms, back, or around waist
135
How do you extract tumbu fly larvae?
similar to the way dermatobia is extracted (surgically then light pressure)
136
What happens once the tumbu fly larva has fully developed?
exits skin, falls, burrows, pupates in soil, emerges
137
What are the two nicknames of the tumbu fly?
mango worm
tumbu fly
138
Sanguinivorous myiasis
Congo floor maggot
139
Congo floor maggot
Sanguinivorous myiasis
140
Where is the Congo floor maggot (sanguinivorous myiasis) found?
Sub-Saharan Africa
141
Does the Congo floor maggot (sanguinivorous myiasis) live on or in the host?
NOT on NOT in host
142
If not on or in the host, where does the Congo floor maggot (sanguinivorous myiasis) live?
sucks blood of burrow-dwelling aardvark, hyena, warthogs, occasionally sleeping humans
143
What does the Congo floor maggot (sanguinivorous myiasis) feed on?
sucks blood BUT DOES NOT ENTER BODY
144
What is the only known blood sucking maggot to feed on mammals?
Congo floor maggot (sanguinivorous myiasis)
145
Where do female Congo floor maggots (sanguinivorous myiasis) lay their eggs?
on dry earth or earthen floors of huts
146
When do Congo floor maggot (sanguinivorous myiasis) larvae feed? How long do they feed? What do they do after they feed?
nocturnal so at night
20 minutes
fall to the ground
147
How many larval instars do Congo floor maggots (sanguinivorous myiasis) have? How long is required to pupate? About how long is a completed life cycle?
three larval instars
two weeks
10 weeks
148
Is the lifecycle of the Congo floor maggot (sanguinivorous myiasis) continuous or once a year?
continuous throughout the year
149
How large can a Congo floor maggot grow?
18 mm long
150
What disease does the Congo floor maggot spread?
no known disease
feeding results in irritation and swelling
151
What is the phenomenon called sanguinivorous myiasis?
the maggots who are blood sucking
152
What is a developing medical innovation being used by progressive medical practitioners?
using medical maggots rather than a scalpel to rid of non-living tissue
153
What are three non-myiasis situations of maggots?
- wound debridement using maggots to remove necrotic tissue
-calliphoridae larvae feed specifically on non-living tissue
-prescription methodology regulated by FDA
154
What family are medical maggots?
Calliphoridae
only the ones that will feed on dead tissue
155
What are the advantages of using medical maggots rather than a scalpel?
they only eat dead tissue, so live tissue will not be rid of
they have antibacterial enzymes which kill unwanted bacteria
156
What is FDA regulated?
medical maggots used in larval debridement are FDA regulated medical devices
newly hatched larvae are sent to the clinic
157
Why is it okay to allow maggot larvae feed on skin for medical significance?
they only consume necrotic tissue and do not damage living tissue
158
What is needed to allow maggots to eat the wound?
A dressing that allows air exchange must be used to seal the maggots in the wound
159
How long do medical maggots feed and what happens once they stop?
feed for only a few days
once they stop, they must be removed and properly disposed of
160
What do medical maggots feed on?
only necrotic tissue
161
What do medical maggots stimulate?
wound healing
antibacterial secretions
secrete allantoin
162
Explain benefits of medical maggots.
small mouthparts so they are able to selectively remove dead tissue
secrete substances that dissolve necrotic tissue and combat infection which stimulates healing
163
Why wouldn't a physician use Cochliomyia hominivorax as medical maggots?
they are the only calliphorid species that feed on living tissue
164
