Parasitology 1 Flashcards
1
Q
What is the equation for control and what does each mean
A
C = M + E + T
Management - hygiene, fences
Epidemiology - using vector, intermediate hosts, temperature and environmental conditions
Treatment - will have to use drugs but resistance issue
2
Q
What are the 4 main elements of the parasite lifecycle
A
1) infection - host, feed, lifecycle
2) location - where, damage
3) transmission - how leaves the host, size
4) treatment and control - hos prevent infection, drugs, block transmission
3
Q
what is the paratenic host
A
parasite acting as a passenger, just hold parasite within and gets eaten
No development no sexual reproduction just transport
4
Q
List 3 examples of how parasites change host behavior
A
1) Liver fluke - dicrocelium
- Manipulates host(snail) to produce slim that ants love
- Forces ant to leave the colony and climb long stalks of grass and easy to eat areas for grazing definitive hosts
2) Leucohloridium
- Infect snail gets into eye stalk, flashing, enlarged hoping a bird will come and eat it
3) Nematomorphs
Larvae need water make host (arthropods) commit suicide in water
5
Q
What defines crustaceans, insects, arachnids
A
crustaceans - >5 pairs legs
Insects - 3 pairs legs
Arachnids - 4 pairs (adult), 3 pairs (larvae)
6
Q
What are the 2 important features of the arthropods gastrointestinal system
A
1) Malpighian tubes - series of tubules that connect to central gut system, how arthropods breathe
2) Salivary glands - acts as a vector for arthropods to transmit other parasitic organisms
7
Q
List 3 features of arthropods
A
1) Cuticle: chitinous exoskeleton, impervious to many chemicals
- Many chemicals designed to fight this feature
2) Muscles: internal, attached to exoskeleton
3) Open circulatory system, blood free in haemocoel
8
Q
what is the brain of the arthropods
A
oesophageal ganglia
- ganglion in each segment
9
Q
arthropods respiratory system: trachea system for terrestrial forms what structures involved and what used for
A
- Valves scattered along the body called sphericles and can open and close depending on the environment and air dispered along the body
- Important for identificated, counting spheracular plates in the sphericles can determine between species
10
Q
List the 4 types of parasitism, describe and give a general example
A
1) Obligate parasites - must have a host (flea)
2) Facultative parasites - can survive without host (flies)
3) Permanent parasites - on host all the time (lice)
4) Intermittent parasites - visit host periodically (mosquito)
11
Q
what are the 3 general chemical control methods used for athropods
A
1) repellents (don’t kill such as DEET)
2) chemicals acting on the nervous system
3) growth regulators
12
Q
What are the 8 classes of chemicals that act on the nervous system and general mechanism and environmental impact
A
1) chlorinated hydrocarbons
- banned as biomagnify
2) organophosphates - inhibits acetlycholine esterase, becomes paralysed, non-cumlative, breaks down
3) carbamates - similar mode as organophosphates, persistes 4-6 weeks
toxic to vertebrates
4) formamidines - highly toxic to horses and chiuzwazars
5) Pyrethroids - synthetic persist 7-14 days, act on sodium channels - paralysis, toxic to vertebrates
6) macrocyclic lactones - very common and potent, - Act on glutamate-gated chloride channels which leads to flaccid paralysis
7) neo-nictinoids & others - non-toxic, banned in some countries due to association with bee collapse syndrome
fipronil - frontline, imidacloprid - advantage
8) Benzimidazole
13
Q
what are the major groups of macrocyclic lactones and examples within
A
1) Avermectins: examples - Ivermectin, Abamectin, Selamectin
2) Milbemycins: examples - Moxidectin
14
Q
List the 8 classes of chemicals that act on the nervous system
A
i. Chlorinated hydrocarbons
ii. Organophosphates
iii. Carbamates
iv. Formamidines
v. Pyrethroids
vi. Macrocyclic lactones
vii. Neo-nicotinoids & others
viii. Benzimidazole
15
Q
Growth regulators how used and mechanism
A
- Combined in treatment program with one of the chemicals used on the nervous system
- Analogues of insect growth hormones
○ Interfere with growth/moulting/egg laying - Lower chances of insecticide resistance occurring with combination as it will prevent the survivors from nervous system destroying chemicals from reproducing
16
Q
Pentastomida mouth structurs and hosts
A
- 4 hooks and mouth create the 5 appendages - pentastomes
- Parasitic in respiratory system of birds, mammals and reptiles
- 2 hooks on either side of the mouth
17
Q
Linguatula serrata what is it, where found, zoonotic?, clincial signs, diagnosis and treatment
A
CRUSTACEANS - Pentastomida
- Tongue worm of the dog
- Not a worm or in the oral cavity
- Found in nasal cavity of domestic and wild dogs
Zoonotic
Clinical signs : nasal discharge, irritation
Diagnosis : find eggs in faeces - millions
Treatment : Ivermectin
18
Q
Linguatula serrata what type of lifecycle, hosts and stages
A
Indirect lifecycle
Intermediate host - rabbits, humans, sheep
Definitive host - dog or human
1) Faecal oral route - oral ingestion of the egg with embryo within
2) Several larval stages L 8 - L 9 the instart stages
3) Larvae penetrate the intestinal wall and start moving into tissues and start development - many stages within the intermediate host
4) Definitive host needs to eat intermediate host to become infected
5) After ingestion lodge in upper digestive tract and crawl into nasal cavity
19
Q
Armillifer armillatus what is host species, zoonoic? lifecycle
A
Important in snakes
- Parasite of reptiles
- Small mammal or arthopods as intermediate host
- Zoonotic but rare
Definitive host has to ingest the intermediate host in order for sexual reproduction
20
Q
Describe the Antennae and wing characteristics of Nematocera, Brachycera and Cyclorrhapha
A
Antennae Nematocera - segmented, thin Brachycera - thicker still segmented Cyclorrhapha - branching arista of the end point Wings Nematocera - longer thinner Brachycera - thicker more robust Cyclorrhapha - similar to brachycera
21
Q
Nematocera features:
size, antennae, larvae, feed, type of parasite, host
A
- small flies (up to 3mm) - elongated
- antennae long and slender
- larvae and /or pupae are AQUATIC - need high moisture content such as cow patties
- females parasitic - need a blood meal
- intermittent parasites - need a host 100% to complete lifecycle but happens randomly, not permanent parasite
- often not host specific can bite anything
22
Q
List the 3 effects Nematocera have on the host
A
1) irritation due to bites
2) blood loss
3) VERY GOOD VECTORS
1. viruses - blutongue
2. bacteria - anthrax
3. protozoa - malaria
4. nematodes - dirofilaria (heartworm)
23
Q
Culicoides features:
identification, lifecycle, feed, effects on host
A
Identification : spotted wings
Life cycle : larvae develop in water, mud, sand or dung
- males/females feed on nectar, females also need a bloodmeal - can feed heavily
- Painful bites - ciliserae that cut into the host
24
Q
What are the 3 main groups of species for Cullicoides and where breed and host
A
- “maritime species” C. immaculatus, C. marmoratus breed in saline waters
- “native species” C. marksi breed in fresh water, feed on marsupials and stock
- “introduced species” C. brevitarsis, C. wadai breed in cattle dung - not native to Australia, efficient vectors
25
List the 2 maritime species where breed, when feed, host and zoonotic?
C. immaculatus, C. marmoratus
- breed in mangroves
- crepuscular (feed at twilight)
- not host specific
- human nuisance
26
List the native species where breed, what season abundant, when feed and on what and what is important
Culicoides marksi
- breed in pools of water
- abundant in wet season in northern Australia
- crepuscular - twilight
- feeds on legs and belly of cattle
important - transmits the nematode Onchocerca gibsoni
27
List the 2 introduced species, when feed, where breed and bite, why is it significance
- Crepuscular - feed at twilight
- breed in cattle dung* - moist
- bite on dorsal midline
Significance :
- cause “Queensland itch” in horses
○ Lesions around tail, rump, back, poll, ears
○ Hypersensitivity to bites
○ Use repellents and stable horses just before twilight, clean up dung
- transmits bluetongue - horrible virus that sheep farmers don't want, wipe out sheep
28
List differences between Culicoides brevitarsis
| and Culicoides wadai in terms of distrubution and vector
```
Culicoides brevitarsis
- wide distribution
- inefficient vector with bluetongue
- Worse with the Queensland itch
Culicoides wadai
- limited distribution
- effective vector with bluetongue
```
29
Simuliidae features:
- have a hump back
- slicing cliserae
- life cycle aquatic - rivers
- larvae are carnivorous - lots of damage
- can cause swarms during floods
30
A.pestilens and S. damnosum significance and effects on host
black flies
- transmits Onchocerca gutturosa of cattle and O. volvulus of man (in Africa - river blindness)
- effect on hosts : severe irritation
31
Phlebotomus identification and significance for vets
```
sand fly
- hairy wings
Significance
- vectors of protozoan disease leishmaniasis
○ Painful lesions, difficult to treat
```
32
Culicidae features, larvae, feed, when present, significance and control
- larvae aquatic
- females feed on blood
- males non-parasitic
- diurnal, nocturnal or crepuscular - if you know when they bite can use as a control method
Significance :
cause : irritation, blood loss
- act as vectors*****
Viruses : yellow fever, equine encephalitis, dengue, zika
Protozoa : malaria
Nematodes : Dirofilaria immitis - heart worm
Control : removing breeding sites; repellents
33
Features of Brachycera how large, antennae, pain, larvae, where found and significance
```
Horse and march flies
- very large, slow flies
- short antennae (looks like mustache)
- very painful bite
- larval stages aquatic
- coasts and forests along creeks
Significance
- effects on host : irritation and blood loss
- vectors for trypanosomes, anthrax, some nematodes (as they are so large)
```
34
What are the two main features of cyclorrhapha
- Short antenna with arista
| - flies that breed in vegetable or animal material
35
Features of Oestridae - Oestrus
| size, mouth piece, eggs, larvae
- large flies (may resemble bees)
- vestigial mouth parts - cannot feed - not parasitic at this stage
- lay eggs or are viviparous (lay live young)
- LARVAE ARE PARASITIC
○ larvae are endoparasites
○ three larval stages in host
pupate on ground - needs to have a thick outer shell, some have spines
36
Gasterophilus what is it, what larval stages, pathogenesis and eggs
- 3 larval stages within the stomach
- Not a lot of pathogenesis involved
- Lay eggs on legs, annoying and sticky so horse bite them off and ingest
37
List the 3 species of Gasterophilus and how to identify with eggs, colour, where found and how hatch
1) G. intestinalis eggs yellow, anywhere on front of body, hatch when licked (eaten)
2) G. nasalis eggs pale, laid between mandibles, hatch spontaneously
3) G. haemorrhoidalis eggs black, laid around lips, hatch spontaneously
38
Gasterophilus where are the first, second and third instars found
First instar : migrates though mouth and gums
- Can be quite painful
Second instar : attaches in stomach - bathing in nutrients
Third instar : in stomach
39
Body spines for gasterophilus where are they found and what are they used for
- Spiracles at posterior end (appears to be eyes) - used to breathe, can identify species between
Hooks at anterior end for attachment
40
Body spines for gasterophilus where are they found and what are they used for
- Spiracles at posterior end (appears to be eyes) - used to breathe, can identify species between
- Hooks at anterior end for attachment
41
Treatment and control of gasterophilus
Treatment : organophosphates (dichlorvos, trichlorphon) or/and macrocyclic lactones (ivermectin, moxidectin)
- Resistance not an issue as much but should always
Control : treat in winter when flies are absent washing or grooming to remove eggs of little value by itself but good management process
42
What is the lifecycle of oestrus ovis and when most active
1. lays larvae on external nares
2. larva crawls into nasal cavity
3. all larval stages found in nasal cavity - 3 moults and instars
4. third instar sneezed out
5. pupae develop in soil
- flies active in summer
43
What is oestrus ovis, where found, effects on sheep and treatment
- nasal bot of sheep and goats
- fly viviparous
Effects on sheep
- Agitates sheep when laying larvae
- Chronic nasal discharge
- Predisposes to pneumonia
- NOT A VECTOR
Treatment
- Organophosphates
- Macrocyclic lactones
- Trematocides (rafoxanide, closantel)
NB: may occasionally be zoonotic
44
What is the lifecycle of Hypoderma Bovis
1. Lay eggs on the front of the cattle
2. Annoying and pick and ingest the eggs, if not ingested and land on floor
3. L1 travel through the host from anywhere it penetrates to the spinal cord (if large enough infestation nerve related issues)
4. Go through 2 moults getting larger
5. 3rd larval instar will push out through the back of the cow and fall on the ground
6. Pupate
Adults form on the ground
45
2 features of Musca
1) spiracles to help breath
| 2) aristae present
46
Musca domestica what is important
- Involves in mechanical transmission of pathogens
○ Bringing pathogens with them, not acting as vectors (no development)
○ Nasal scald
○ Fly dermatitis
- Intermediate hosts of nematodes and cestodes
47
Musca vetustissima common name, where breed, what season and what does it cause
- The bush fly
- breed in cattle dung
- overwinter in northern Australia
- cause similar problems to M. domestica
48
Stomoxys calcitrans common name, lifecycle, effects on host
the stable fly
Life cycle : breed in decaying organic matter
Effects on host : both sexes feed on blood
- bite anything (mammals)
- horses and dogs commonly affected (lumps n the rump)
49
Haematobia exigua* common name, feature and moutpiece, where from, host
the buffalo fly IMPORTANT
- small grey fly
- rigid, biting mouthparts
- introduced from South East Asia
- feed on cattle, buffalo, horses and dogs
50
what is the life cycle of haematobia exigua how long is lifecycle and temperature needed
buffalo fly
1. flies remain on host
2. die in 1-2 days away from host
3. leave host to lay eggs
4. breed in cow dung
5. emerging flies have 1-2h to find a host
6. need a blood meal to breed
7. adults live for 10-20 days
- need temperatures > 20ºC
- life cycle takes 7-11 days
51
What is the epidemiology of Haematobia exigua
- spread by travelling cattle
- can travel up to 7 km on prevailing winds - remember need to find quickly
- geographical distribution limited by temperature and moisture
- Distribution shifts due to seasonally, limited by temperature and moisture
52
Haematobia exigua what are the effects on host
- bites are painful
- cattle rub to relieve irritation
- 2000-3000 flies a heavy infection
- loss of condition or delay in fattening
- milk production drop - more time trying to remove flies than eating
- vector of Trypanosoma evansi & of nematode Stephanofilaria sp.
53
List 4 control methods for Haematobia exigua
buffalo fly
1) fly traps (tunnel trap) - common
2) ear tags impregnated with insecticides - change insecticide with the season
3) insecticides (ivermectin) which persist in dung where instars going through moult
4) dung beetles to remove the dung
* Integrated control (reduce reliance on chemicals) - 3 pronged approached
54
Hippoboscidae common name, how feed, females, larvae, where found
- exclusively parasitic (blood feeders)
- feet with strong claws
- females viviparous
- larvae pupate immediately
- Always found on the host
55
Melophagus ovinus special characteristics, where live, when hatch, how long live and list 4 effects on host
```
lives in wool
§ pupal case attached to wool
§ pupae hatch in 19-36 days
§ live 4-5 months
Effects on host :
1. blood feeders
2. cause anaemia
3. stain wool (“ticky wool”)
4. transmit Trypanosoma (protozoan)
```
56
Important features of calliphoridae:
| what important for, what feed of, what type of parasites and major diseases they cause
- Important environmentally - clean up
- Breed in decaying organic matter
- Adults feed on decaying organic material or nectar
- Facultative parasites (usually)
Major diseases :
- Blow fly strike of sheep (cutaneous myiasis)
- Screw worm fly (exotic)
57
Lucilia cuprina what responsible for, what type of parasite and how long is the lifecycle
- Responsible for > 90% of strikes
- Almost obligate parasite
○ Can breed in carcasses but outcompeted - secondary strike species prefer and outcompete in this niche
Lifecycle - Entire life cycle 17 days (in summer) - seasonality can extend
58
Lucilia cuprina what is the lifecycle
1. Eggs laid in batches in fleece
2. Laid in afternoon, hatch at night
3. First instar needs protein meal (cannot penetrate skin) just feeding off the debris around it - dag with urine, faeces attracts
4. Second instar penetrates skin, (feeds on tissues)
5. Third instar matures by 2-19 days
6. Drops to ground at night
7. Burrows into soil
8. Pupates (3-7 days)
9. Overwinters as pupa
10. Emerging females need protein meal to produce eggs
59
what is the area of the Lucilia Cuprina lifecycle that can be exploited and what are most strikes like and what makes it worse
- Only mate once - if can mess with the one mating can be used as a control measure
- Most strikes are “covert” and heal - with primary flies - if low infection then sheep able to hide well
- Secondary flies can invade and extend the wound
60
What are features of small covert infection day 1-2, 3, 4, 6, features
- Days 1-2 sheep irritated
- Day 3 temperature rise
- Day 4 maggots drop, smell
- Day 6 temperature falls
- Healing slow but complete
…in bad years with secondary and tertiary - mortalities can be up to 30%
61
What are the 4 types of fly strike
* breech strike - most prevalent
* body strike
* poll / head strike (rams)
* pizzle strike (rams & wethers)
62
Describe the pathogenesis of fly strike
- Normal sheep are not struck by flies
- Need olfactory stimulus to attract flies - bacteria such as dermatitis
- Need proteinaceous exudate on skin for first larval instars
63
What is the most common form of flystrike, how occurs and what predisposes
Breech strike
- Soiling of fleece by urine or faeces
- Scouring due to nematodes (can reduce prevalence 10 fold)
- Wrinkles predispose to strike - genetic predisposition - artificial selection with wrinkle score for breech and body
64
What is the seasonal prevalence of fly strike
- Fly numbers determined by temperature and rainfall - can have continuous or bimodal distribution
- Flies overwinter as pupae, emerge in spring - 3 generations
- Summer too dry for eggs ad first instars
- Autumn moister & cooler - 2 generations
- Pattern of infection generally bimodal
- If summer is wet, flies active all summer
65
What are the 2 main control methods and examples within
1) render sheep less susceptible
- crutching, breed for sheep with suitable fleece characteristics
2) reducing fly numbers
- fly traps, burn or deeply bury carrion, vaccines, chemicals - organophosphates and growth regulators
66
Chrysomya rufifcacies what is the common name, where found and what feed on
Common name: the hairy maggot (spinal projections make it look) blowfly
- Found in Australia
- Larva feeds on other maggots
67
Chrysomya bezziana what is the common name, what is the obvious feature, where found, what leads to
Common name : the Old World screw worm fly
- Blue blowfly
- Oral myiasis
* Not present in Australia
- Secondary flies for fly strike
68
Cochliomyia hominivorax what is the common name, what similar to, what is different about it
Common name : the New World screw worm fly
- Similar to C. bezziana
- Eradicated in USA using sterile male technique
- Sporadic outbreaks due to travel
69
What are the main features of Siphonaptera (fleas)
- head, thorax, abdomen
- wingless (‘aptera’)
- laterally compressed - distinct from lice
- heavily chitinised - very hard to destroy
- legs with claws
- adapted for jumping - powerful hind legs
70
What are the main physical features on the Siphonaptera and what is the main thing used to differentiate between different fleas
- eye (AU)
- antenna (AT)
- palps (MT) - guide and protect mouthpiece
- feeding tube (EP)
- combs: - DISTINCTIVE FEATURE
○ genal ctenidium
○ pronotal ctenidium
○ Some fleas don't have combs others have them in different locations - NEED TO KNOW
71
What is the lifecycle of Siphonaptera
1. eggs fall to ground
2. larvae hatch
- recognised by “anal struts”
3. 3 larval stages (instars)
4. feed on detritus
- pupal stage
5. adult flea emerges
72
Siphonaptera host specifics: what type of parasite, how to get on host, what meal needed, where found
- can survive long time without host
- jump onto host
- female needs blood meal - in order to lay eggs
- obligate parasites but not permanent
- can remain on host (permanent) or spend time away from host (intermittent)
- not host specific
73
Siphonaptera effects on host
- capillary feeders, saliva contains anticoagulant
- blood loss, irritation, hypersensitivity
- intermediate hosts
○ (Dipylidium caninum, Acanthocheilonema (Dipetalonema) reconditum)
- vectors of bubonic plague (Yersinia pestis)
74
C. felis and C. canis what found on, what dependent on for growth, where is most population found and how hatch
- most common fleas on cats & dogs
- development temperature dependent
- flea problems occur in summer
- most of population is OFF host :
○ eggs 50% - envir
○ larvae 35% - envir
○ pupae 10% - envir
○ adults 5%
- pupae stimulated to hatch by vibrations
75
What affect does C. felis and C. canis have on the host
1. papular dermatitis in man - household pest
2. flea bite dermatitis in dogs - (=summer dermatitis)
3. Milliary eczema in cats
○ High burden of fleas
○ due to salivary antigen
○ develop type I hypersensitivity
○ incessant scratching, hair loss base of tail, thighs
76
What are the two main areas of controls that are important when dealing with Siphonaptera and types within
fleas
1) on the host
1. repellents
2. insecticides, powders & shampoos, oral and tropical treatments
3. insect growth regulators & insect development inhibitors - used with other treatment
4. flea salivary antigen injection to desentise the dog
2) environments
1. house
2. bedding
3. outside
77
List the insecticides and insect growth regulators that are used to control Sipphonaptera
Insecticides
- fipronil: dogs and cats - frontline - CNS disruption
- selamectin: dogs and cats - macrocytic lactone
- synthetic pyrethrins: dogs with some for cats - others may be toxic
Insect growth regulators
- tropical treatment - iufenuron
- flea collar - methoprene
- oral treatment - cyromazine
78
Echidnophaga gallinacea common name and main characteristics
”stick-fast” fleas - don't want to leave once attached
- poultry stick-fast flea
- identified by short thorax and no combs
- stay attached at single site
- not host specific do prefer poultry
- common in hot dry areas
- other species occur on native mammals (e.g., E. perilis, E. myrmecobii)
79
Pulex what is the main species, identification, hosts and effect on host
```
The human flea
Pulex irritans
Identification :
- no combs
Hosts :
- humans, pigs, dogs
- common in free range piggeries
- Issue as hypersensitivity - rub up against - production losses
```
80
Spilopsyllus cuniculi common name, identification, host, vector, what is different about it
Identification :
- genal comb “vertical”
- introduced
- vector of myxomatosis
- host specific - unusual for
- only breeds when host breeds - attach to female rabbit - hormones sets off the breeding and egg laying
- breeding of flea initiated by hormones in rabbit blood - once rabbit born new fleas can jump onto new hosts
○ Large amounts can be found in a population
- sometimes found on cats
81
Phthiraptera physical features two types and host
```
Lice
- head, thorax, abdomen
- wingless (‘aptera’)
- dorso-ventrally flattened
- antennae with 3-5 segments
- legs with claws - differ depending on diameter of hair of specific host - IDENTIFICATION
○ adapted for grasping
- Two types - sucking and biting fleas
Features :
- host specific - VERY
○ site specific - VERY
- claw size related to fibre diameter
- obligate, permanent parasites - different from flees - cannot survive off host
```
82
List the control methods for phthiraptera and what similar to
* Louse infestations are readily treated with many flea control products.
* Fipronil, imidacloprid and selamectin are all effective.
* Topical permethrin can be used on dogs with good effect.
83
Lifecycle of the lice, how long
- egg (nits) stuck to hair
- no metamorphosis
- 3 nymphal stages - not larval
○ Look similar to adults and just grow - no methorphus
- lifecycle 2-3 weeks
84
Anoplura what is the common name, head shape, where feed, habitat, colour/size, tranmission and treatment
- sucking lice
- head narrow, pointed
- feed on blood or tissue fluids on mammals
- coarse hairs (mane, tail)
- eggs readily visible
- large, black or blue
contact -
(*except L. pedalis on pasture,
- H. asini on grooming equipment)
- topical or oral insecticide
85
Mallophaga what is the common name, head shape, where feed, habitat, colour/size, tranmission and treatment
- biting lice - not piercing
- head broad, rounded
- feed on epidermis, feathers
- on birds & mammals
- fine body hairs, eggs concealed
- small, yellow
- contact
- topical insecticide only
86
Linognathus pedalis what is it, what host, what is special about it
Sucking lice of sheep,
foot louse
can survive in pasture for 18 days - abnormal for louse to survive so long off host
87
Damaliia ovis what is it, feature, how prevelent and what rainfall needed
body louse of the sheep
- small yellow louse
- 30% sheep properties affected
medium rainfall areas
88
Damalinia ovis common name and effect on host
Body louse of the sheep (biting lice)
- feeds on stratum corneum
- hypersensitivity
- irritation, rubbing
- “pulled wool” - economically want to avoid - decrease quality of wool
- reduced wool production
89
Damalinia ovis common name, diagnosis and what are they sensitive to
Body louse of the sheep (biting lice)
: find lice on sheep
- part wool and look
- minimum detection level 1000 lice per sheep
- lice colonial and photophobic - CONTROL - prefer long wool to protect
90
Damalinia ovis life cycle and what environmental temperatures needed
```
• eggs (nits) hatch in 10 days
• entire life cycle 35 days
• can live off host for 1 week
• **affected by temperature
• optimum temperature 37ºC
- at low temp, eggs do not develop
- fleece maintains temp of 37ºC
- above 39 ºC few eggs laid
- fleece temperatures in summer can be 45 ºC
○ lower numbers in summer due to heat
• if humidity > 90%, eggs do not hatch
• heavy rain can kill eggs
• exposure to sunlight kills lice
- shearing removes 30-50% of lice
- after shearing lice exposed to UV radiation
```
91
What are the 3 main ways to treat damalinia ovis
body louse of sheep
1) treat after shearing
2) plunge dip, shower dip - must be fully wet, do get dilution effect, stripping of insecticide occurs
3) pour-on, backline treatment - can use organophosphates, synthetic pyrethroids, insect growth regulators, spinosad, macrocyclic lactones, neonicotinoid
- don't underdose and make sure you get the stomach
92
What are the two lie found on the horse and what transmistted by
```
1) Body louse
Damalinia equi - biting lice
2) Sucking louse
Haematopinus asini
Transmitted by contact
```
93
Sucking lice when most prevelent, what does it lead to and what animals most susceptible
Maximum numbers in winter
causes rubbing
larger numbers in sick animals
94
Haematopinus suis common name, what mistaken for, effect on host
sucking louse of the pig
- very large so mistaken for tick but has 6 legs not 8
1) causes red spots on the skin
2) vector that transmits pox and swine fever
95
What is important about lice found on poultry, what is the most important one and treatment
- All biting lice no sucking
- many genera
- M. stramineus most common cause irritation, feather loss (feed on feathers) , poor growth, reduced egg production
Treatment : dust baths - self groom, aerosols, vaporisers
