Insects & Flies & Bugs Flashcards
1
Q
- What is the species and genus of the common housefly?
- What are its (2) distinguishing features?
A
- Musca domestica
- Four dark stripes on grey thorax
- Wing vien 4 bends to meet vein 3 very closely.
2
Q
- What is the species name for Stable flies?
- What size are they?
- How are they disinguished (2 features) from Musca domestica?
A
- Stomoxys
- 8 mm long, about the size of a large housefly
- grey colour, 4 dark stropes on thorax and several dark spots on the top of the abdomen
- Differentiating Stomoxys from Musca:
- proboscis
- wing venation: 4th vein turns up towards 3rd but does not approach so closely
3
Q
- Name stages of development of house fly
- How long to complete llife cycle?
A
- stages
- egg
- larva or maggot
- pupa
- adult
- 7-10 days
4
Q
- What is the family name for non-metallic blowflies?
- Other common names?
- How distinguished?
- What is distinct about life cycle?
A
- Sarcophagidae or Wohlfartia (flesh flies)
- Distinguishing features:
- non-metallic, usually grey or silver in colour
- thorax 3 longitudinal stripes
- abdomen marked with “chess-board” (Sarcophagidae) or well-defined dark spots (Wohlfahrtia).
- eyes red colour
5
Q
- What are scientific and common names for metallic blowflies?
- Distribution?
- What is their usual behaviour and clinical significance?
- What are their distinguishing features?
A
- Calliphora (bluebottles) and Lucilia (greenbottles)
- worldwide distribution
- normally lay eggs on rotting meat etc, sometimes also on purulent wounds and excreta. Presence of larvae does not usually lead to serious consequences as they feed on pus and dead tissues.
- Distinguishing features: blue or green metallic colour on thorax and abdomen, prominent bristes on dorsal surface of thorax (Chryosomia & Cochliomyia - screw worms - lack these)
6
Q
- What are screw worms?
- What is their life cycle?
- Identification of flies and larvae?
- What diseases
A
- larvae of Cochlyiomyia hominovorax (new world screw worm) and Chrysomya bezziana (old world screw worm)
- obligate parasites of living tissue that invade natural orifices, nose, mouth, eyes, vagina resulting in serious tissue destruction and pain
- blue-green metallic colour of adult flies
- no bristles on thorax)
7
Q
- Screw worms: life cycle and disease
- Morphology?
- Distinguish from what?
A
- larvae of Cochlyiomya hominovorax (new world screw worm) and Chrysomya bezziana (old world screw worm)
- eggs laid directly on skin, give rise to larvae that are
- obligate parasites of living tissue that invade natural orifices, nose, mouth, eyes, vagina resulting in serious tissue destruction and pain
- larvae have rows of stout spines like a screw thread
- distinguish from
- Dermatobia (human bot-fly)
- larvae have hooks on each segment
- Cordylobia (tumbu-fly or mango-fly)
- with smaller spines or spicules over dorsal surface
- Dermatobia (human bot-fly)
8
Q
- What are Cordylobia and Dermatobia?
- What disease do they cause?
- What are the distinguishing features of the larvae and from what should they be distinguished?
A
- Cordylobia anthropophaga is tumbu-fly or mango-fly (Africa)
- Dermatobia hominis is (human bot-fly) (South America)http://entnemdept.ufl.edu/creatures/misc/flies/human_bot_fly.htm
- they cause furuncular myiasis
9
Q
- distinguish between screw worms , tumbu-fly or mango-fly and human bot-fly
A
- Screw worms:
- larvae of Cochlyiomyia hominovorax (new world screw worm) and Chrysomya bezziana (old world screw worm)
- obligate parasites of living tissue that invade natural orifices, nose, mouth, eyes, vagina resulting in serious tissue destruction and pain distinguish from
- flies causing furuncular myiasis:
- (Dermatobia (human bot-fly)
- larvae have hooks on each segment
- Cordylobia (tumbu-fly or mango-fly)
- with smaller spines or spicules over dorsal surface
- (Dermatobia (human bot-fly)
10
Q
- What is Musca sorbens?
- What is it’s life cycle and preferred food?
- Clinical significance?
- Appearance?
A
- Musca sorbens is the
- bazaar fly or bush fly
- it lives outdoors and in the open
- lays eggs on human (preferred) or animal excreta in the open, not in pit latrines
- most frequent of flies seeking eyes, more attracted where discharge from eyes and/or nose
- may be common in refugee camps
- major transmitter of trachoma
- difficult to distinguish from Musca domestica
11
Q
- Musca domestica
- life cycle?
A
- feeds on human food, garbage, excreta, decayed plant and animal matter
- feeding sites 100-500 m from breeding sites, often in same decaying organic matter it feeds on
- found by day near food sources and breeding sites
- 7-10 days
12
Q
- What is the medical significance of the common house fly? i.e. transmits which diseases?
A
- omnivorous, feeds on feces and food
- transmits
- Enteric bacteria
- Shigella
- Salmonella
- E. coli
- Cholera
- Enteroviruses, inc. polio
- ¿Helminth eggs?
- Enteric bacteria
13
Q
- How does the common housefly transmit disease?
A
- defecation (every 5 minutes)
- regurgitation
- transport on body surface
14
Q
- What is the Lesser House Fly?
- What is distinctive about it’s appearance?
A
- Fannia cannicularis
- worldwide distribution
- smaller than the common housefly (3.5-6 mm length), does not have same 4th vein pattern
- otherwise similar in behaviour and clinical significance
- likes chicken farms
15
Q
- what kind of community control measures can be applied to control of houseflies and blowflies?
A
- although effective, spraying with insecticide is
- expensive
- leads to resistance
- therefore good waste disposal practice
- cover refuse with >25 cm soil
- keep only working edge of tip exposed
- make sure tip is tightly packed so increased temp kells larvae
- Disposal of human and animal excreta
- ventilated pit latrine
- manure piles
16
Q
- name four flies that are obligate parasites and two that are facultative parasites
A
- Obligate parasites
- furuncular boil-like swellings with one fly larva per boil
- Tumbu-fly or mango-fly (Cordylobia)
- human bot-fly (Dermatobia)
- invasive (screw-worms)
- Cochlyiomyia hominovorax (new world screw worm)
- Chrysomya bezziana (old world screw worm)
- furuncular boil-like swellings with one fly larva per boil
- Facultative parasites
- Non-invasive
- Lucilia (Green bottles)
- Calliphora (Blue bottles)
- Non-invasive
17
Q
- What is this?
- What is latin name?
- What does it look like? where found?
- Life cycle?
- What is normal host?
- lesions
A
- Tumbu fly larva
- Cordylobia anthropophaga
- Adult is inconspicuous brown coloured fly
- Africa
- Normal host is rat
- lays eggs on urine soaked clothes or sandy soil
- grub-shaped larvae burrow into skin to form boil-like swellings
- common around buttocks, genitalia and back
- emerge from skin after 8 days and fall to ground, where they pupate in soil
18
Q
- Cordylobia:
- common name?
- how treated?
- how prevented?
A
- common name tumbu-fly
- cover surface of furuncle with liquid paraffin
- this deprives larva of oxygen
- the paraffin coats the larva, which may then be able to be expelled with pressure applied to the sides of the furuncle
- conrolled by ironing oclothes
19
Q
- Dermatobia
- common name?
- life cycle?
A
- Dermatobia hominis
- human bot-flye or New World myiasis
- eggs attached to biting insect
- mosquito or Stomoxys
- larvae hatch and drop onto skin
- burrow into skin forming boil-like swelling
20
Q
- What are the identifying characteristics of Dermatobia?
- (what’s the disease and how transmitted)
A
- stout rose-thorn spines
- shape, esp of 2nd instar
- New World Myiasis
- dermatobia eggs attach to mosquito and are laied on human hosts
21
Q
- What are fleshflies?
- Common name?
- where found?
A
- Sarcophagidae
- common in refuse, butchers shops etc
- larvae of some occasionally cause myiasis (facultative parasite)
22
Q
- What is non-invasive myiasis?
- fly habitat?
- What is it caused by?
- substrate?
- therapeutic use?
- Identify the larvae
A
- caused by bluebottles (Calliphpra) and green bottles (Lucilia)
- usually breed in similar habitats to houseflies
- will infest and consume necrotic tissue e.g. foul smelling wounds, ulcers etc, sometimes found under bandages
- usually do not cause harm since they feed on dead and decaying tissue
- Baer’s maggot therapy
- Larvae without screw thread of spines
23
Q
- Dermatobia treatment?
A
- vaseline strategy may be insufficient
- may require surgical intervention or injection of anesthetic into base
27
Q
What are these?
Characteristic features.
What diseases do they transmit?
A
- males scutum covers whole of dorsal surface, may be patterned
- females resitricte to anterior part of dorsal surface
- when fully fed may be hard to see in females
- Diseases
- Lyme disease - Borrelia burgdorfi
- Q fever - Coxiella burnetti
- Colorado tick fever - Coltivirus
- Rocky Mountain Spotted Fever - Rickettsia rickettsii
- African tick typhus (African Spotted fever) - R. africae
- Mediterranean Spotted Fever - R. conorri
- Tularemia - Francisella tularensis
- Tick paralysis - tick toxin in Australia
- Tick Borne Encephalitis - flavivirus in Europe and Russia
- (Tick-borne relapsing Fever - Borrellia species) is transmitted by Argasidae - Soft Ticks
28
Q
What is this?
Distinguishing features?
What disease?
A
- Argasidae - soft ticks
- No scutum
- Tick borne relapsing fever - Borrellia species
29
Q
What are these?
Distinguishing characteristics?
A
- Soft Tick Larvum on left; Hard Tick Larvum on right
- both have only 6 legs (adults have 8)
- only the Hard Tick Larvum has a scutum (as do adults)
30
Q
What is this?
Distinguishing characteristics?
What is the disease?
What is the life cycle relevant to the disease?
A
- Leptotrombidium or Chigger mite, vector of scrub typhus (see eschar with black crust and erythematous halo, picture below)
- only larval stage feeds on blood
- larval mite has 6 legs and many fine hairs
- normally larva fees on small mammals or ground feeding birds, humans are accidental host
- pathogen similar to Rickettsia but is called Orienta tsugumushi
- areas of forest clearings, riverbanks, grassy regions best for infected mites
- more frequent in rainy season
31
Q
What is this?
What might blood test show?
A
- microscopic scabies mite
- burrows into upper layer of skin and lays eggs
- eggs hatch and burrow through skin, may be found at end of burrow
- Eosinophilia, esp in immunosuppressed with hyper infestation (Norwegian scabies)
32
Q
What is this?
Vector for?
A
- adult flea
- vector for
- bacteria, viruses and tapeworms, as well as
- Endemic typhus (murine fever) - Rickettsia typhi
- Plague (Yersinia pestis)
- Tularaemia (Francisella tularensis) - also hard ticks
33
Q
What does this picture represent?
A
- The difference between male and female fleas.
- female left, male right
- the difference is presence of clasper on the male
34
Q
What are these?
ID the species?
What are the distinguishing characteristics?
A
- Fleas:
- Ctenocephalides felis (Cat flea) on left, similar to dog flea (C. canis)
- Xenopsylla cheopsis (Oriental rat flea) middle
- Pulex irritans (Human Flea) right.
- Tell C. felis or canis from the other two by presence of two combs (genal and pronotal)
- Tell Xenopsylla from Pulex by the presence of a meral rod on the 2nd thoracic segment.
-
Xenopsylla or Oriental rat flea (no compbs, meral rod on 2nd thoracic segmant) was vector for the plague bacillus, Yersinia pestis
- bacillus multiply in flea blocking upper GI tract of flea causing it to regurgitate bacilli as it tries to take a blood feed
- Pulex irritans (no combs or meral rod) may transmit Rickettsia typhi, which causes murine typhus.
- bacteria grow in epithelial cells lining flea’s gut wall and are excreted in feces, then scratching rubs bacteria into wound.
35
Q
- What is this?
- How can you tell?
- What disease does it carry?
- What is the natural reservoir for this disease?
- Where is it found?
A
- Pulex irritans, human flea
- no combs (not cat or dog flea or Ctenocephalides)
- no meral rod on 2nd thoracic segment ( not oriental rat flea or Xenopsylla)
- vector for murine (rodent) typhus, which is a disease - duhhh- of rats
- which are found in warm coastal areas around the world because they are looking for ships they can get onto to jump off of when they sink - (anybody still reading this? If so, see map)
36
Q
What is this?
What disease does it case?
How is it treated?
A
- Tunga penetrans or Jigger flea (smaller male on right, female on left that has been dug out of someone’s foot)
- Causes tungiasis or jiggers, which can really be pretty nasty - see picture attached (ddx mycetoma, differentiated because mycetoma is painless whereas tungiasis causes intense itching, pain and inflammation and may get secondarily infected)
- usually affects the foot but can get anywhere on the body
- treatment is by careful physical extraction of the intact female
37
Q
- What is this?
- What disease are they a vector for?
A
- body lice (Pediculosis corporis), compare with head lice (Pediculosis capitis) below, which are very hard to tell apart except by context (see picture of P. capitis and egg below)
- Lice have a hemimetabolous life cycle, which means there is no pupal stage: the larvae hatch directly from egg
- body lice are vectors of
- Epidemic or louse-born typhus (Rickettsia prowazekii) and
- Trench fever (Bartonella quintana)
- Both are spread by inhalation of louse feces or bacteria in feces being rubbed into an abrasion, not by the bite.
- also vector for Epidemic relapsing fever (Borrelia recurrentis)
- louse must be crushed first to infect humans: spirochetes enter through mucosa or via cuts and abrasions
38
Q
What are the vectors and organisms for these diseases?
A
39
Q
What is this?
A
Pubic lice
Pthirus pubis
44
Q
What is this?
What other member of this order is medically significant?
A
- Bedbug, one to two medically significant “True Bugs” order Hemiptera
- The other is Triatomine Bug
50
Q
What is Chandipura?
A
- Note rhabdovirus ss RNA virus related to Rabies, transmitted by sandfly
- causes severe encephalitic illness with high (~50%) mortality rate in India
- Chandipura virus (CHPV)
Virus classification
Group:Group V ((−)ssRNA)
Order:Mononegavirales
Family:Rhabdoviridae
Genus:Vesiculovirus
Species:Chandipura vesiculovirus
Chandipura virus (CHPV) is a member of the Rhabdoviridae family that is associated with an encephalitic illness in humans. It was first identified in 1965 after isolation from the blood of two patients from Chandipura village in Maharashtra state, India[1] and has been associated with a number of otherwise unexplained outbreaks of encephalitic illness in central India.
- transmitted by sandfly
51
Q
What is this?
What are the distinctive features?
What is it’s medical importance?
A
- Phlebotamine Sandfly
- small, <4mm
- V-shaped wing configuration when resting
- hairy dorsal thorax
- spindly legs
- Medical importance
− Biting nuisance and allergies
− Leishmaniasis
− Bartonellosis
− Viruses: sandfly fevers and Chandipura
52
Q
What is sandfly fever?
Disease?
A
- Pappataci fever (also known as Phlebotomus fever and, somewhat confusingly, sandfly fever and three-day fever) is a vector-borne febrile arboviral infection caused by three serotypes of Phlebovirus. It occurs in subtropical regions of the Eastern Hemisphere. The name, pappataci fever, comes from the Italian word for sandfly, it is the union of the word “pappa” (food) and taci (silent) which distinguishes these insects from blood-feeding mosquitoes, which produce a typical noise while flying.
- FAR, headache, generally self-limiting
53
Q
What are sandlfy control measures (and their problems)?
A
55
Q
What is this?
What diseases does it cause?
How are the diseases transmitted?
A
58
Q
With respect to the Life Cycle of the Mosquito:
- How long does it last?
- How long for larvae to hatch from eggs?
- Pupa to Form from Larvae
- Adult to emerge?
- Female to lay eggs?
- How does this relate to feeding cycle?
- How many blood meals does a female take in a lifetime?
- How many opportunities does she have to transmit infection?
A
- 10-14 days from one laying to another
- 2-3 for eggs to hatch to larvae
- 5-7 to pupae
- 7-8 for adult to emerg then female feeds and lays eggs in batches after each blood meal
- Female mosquitoes will live < 4 wks
- If an adult female takes 3 blood meals because of the malaria life cycle she can only transmit malaria every 3rd blood meal.
