Lecture 4 Flashcards
(40 cards)
1
Q
Morphology of Bovicola Ovis
A
Head is broad, read
Dark, transverse bands
Feeding: all stages are feeding on epidermal scales, scurf, dried serum, bacteria, suint and other skin debris
2
Q
Biology of Bovicola ovis
A
- All stages found on the host
- In the environment lice do not survive too long
- Lifecycle stages: egg, 3 nymphal stages, adults
- At 37 degrees and 68% relative humidity the lifecycle is completed in 32-34
3
Q
Where do most lice stay with Bovicola ovis
A
Mostly stay near the skin
Shearing can cause
- The loss of 35%-50% of lice that are present in spring
- Can render the microclimate of the remaining 6mm of wool for unsuitable for lice
4
Q
What are the effects of temperature on Bovicola Ovis
A
- D. Ovis prefer to remain in the parts of the fleece that have a temperature of 37.5 +/- 2.5 that is the most favourable temperature for oviposition, feeding and development
- Lice and their eggs are killed by temperatures more than 45 degrees
5
Q
What are the effects of humidity on Bovicola ovis
A
- Immersion in water for 6hr is lethal
- Periodic rains can cause considerable mortality of sheep biting lice
6
Q
What is the epidemiology of Bovicola ovis
A
- Specific to sheep but can tranfer and reproduce in goats
- All sheep are susceptible to lice infestation
7
Q
Transmission of Bovicola ovis
A
- Direct contact
- Indirect - sheering
8
Q
What are the sources of infection of Bovicola ovis
A
- Introduced sheep
- Stray sheep
- Sheep not properly treated
- Lice spread slowly throughout the flock
9
Q
What are dynamics of lice populations of Bovicola ovis
A
- Spring shorn flocks: lice populations generally increase in winter and spring and fall during the summer
- Effects of shearing
- High summer temerature
- Solar radiation
- Heavy rainfall
- Sheep are not shorn in spring
10
Q
Bovicola ovis: spatial distribution of lice in sheep
A
- At most times of the year the populations of lice are highest on the back and along slides
- After shearong a greater proportion of the population is found under the neck, lower flanks and upper legs
11
Q
What are the clinical signs of Bovicola ovis
A
- Irritation - rubbing, scratiching and biting wool
- Reduce quality or quantity of the wool
- Lice detection
- Light infestations is difficult
- Fleece derangement
- Visual inspection
- Detection of lice antigens at shearing
- Use debris that accumulate under sherer’s handpiece
- ELISA or immunochrographic
12
Q
A
13
Q
What another name for Lingnathus pedalis
A
Foot louse
14
Q
What is the morphology of Lingnathus pedalis
A
- Head is short, about as broad as long, not prolonged in front of the antennae
- The lice occurs in clusters, usually at low population level on hairy parts of sheep foot
- In heavy infestations -> clusters above the hock, on the scrotum in the belly wool, rarely on the face
15
Q
What is the clinical signs of Lingnathus pedalis
A
- Mostly in young lambs and rams
- Indirect infestation possible
- Population peak in winter
- Stamping and biting of affected parts
16
Q
Lingnathus ovillus is also know as
A
Face louse
17
Q
What is the morphology of Lingnathus ovillus
A
- Head is broad but twice as long as wide
- Life cycle completed in 5 weeks
- Usually found on the hairy parts of the sheeps face
- As the louse population increases in the winter they spread to other parts of the body
18
Q
What is another name for Lingnathus africanus
A
Post antennal alteral margina are extended
19
Q
How to eradicate lice
A
- Complete muster must be conducted
- Avoid split shearing
- Treat or quarantine introduced sheep
- Maintain boundary fences
- Apply effective chemicals correctly
- Work with your neighbours
- To eradicate lice treat ALL sheep effectively within a few days to 4 weeks of shearing
20
Q
What are lice control strategies
A
- If lice are detected at shearing
- Treat off shears
- If lice detected in long wool sheep
- Do nothing
- Brong shearing time forward
- Long wool treatment
- Long wool treatment reduced the number of lice but will not eradicate lice
21
Q
What drug is resistance common
A
- Synthetic Pyrethroids (SPs)
22
Q
A
23
Q
What is the application of treatment in short wool animals
A
- Plunge dip, shower dip, cage dip
- Short-wool blackline treatment
24
Q
What is the application of treatment for long wool sheep
A
- Hand jet
- Long-wool backline treatment
25
Explain dipping
* Dip all sheep between 10-14 days and 4-6 weeks off shears
* 6in1
* Use disinfectants
* Sheep must be wet at skin
26
Explain the plunge dip
* Labour intensive
* Most thorough and robust means of treating shears for lice infestations
* Swim lenght shoukd ve at least 9 meters
* Sheep should be fit and in good condition
* A minimum of 20 second swimmwith two head dunks is required
* Check sheep are wet the the skin
27
What are the dip methods
* Plunge dip
* Shower dips
* Cage dipping 'fish and chip dipper'
28
What is a short wool backliner
* Easy to use
* Safer than dips for operators
* Small volumes applied along the back
* Most products must be applied within 24h off shears
* Sheep must be cleanly shorn
29
What are long wool backliners
* Easier and quicker than hand get
* Potential for chemical residues in wool
* Expensive
30
Explain how the hand jet works
* Wet sheep to skin level
* 0.5L fluid per month of wool
* Slow job, labour intensive
* Correct pressure of jet is important
* Onyl temporary control method
31
What are the issues in sheep lice control
* Residues
* Resistance
* Occupational health and safety
* Environmental contamination
32
What is another name for Bovicola bovis
* Cattle chewinf louse
33
What is the epidemiology of Bovicola bovis
* Less important in tropical areas
* Common on dorsal parts of body
* Calves and undernourished cattle are most heavily infected
* Self-grooming important for size of population
* More abundant in the winter
* More common on dairy cattle than on beef cattle
* Transmission: direct contact
34
Bovicola bovis: effects on host
* Irritate the host -\> animals rub, scratch, lick themselves -\> alopecia, crusting -\> damage to the fences
* Retard the growth of young animals, reduce the milk production
* Damage to the hides
35
What is the epidemiology of Linognathus vituli
* Up to 2.5 mm long
* 1st pair of legs smaller than 2nd and 3rd pairs of legs
* Heaviest infestation: neck, withers and dewlap
* More common on dairy cows, especially calves
* In heavy infestations on young calves: anemia, loss of hair, alopecia
36
What is another name for Solenopotes capillatus
* Little blue cattle louse
37
What is the epidemiology of Solenopotes capillatus
* Up to 1.5mm long
* 1st pair of legs smaller than 2nd and 3rd pairs of legs
* Spiracles on tubercules which protude from abdomen
* Location: commonly found in clusters on the neck, head, dewlap
38
Explain the epidemiology of haematopinus
* Up to 3.5mm long
* Location: face, around the eyes, base of the horns, neck and dewlap, base of the tail ect -\> heavy infestations may occur anywhere
* Cause of anaemia
39
Explain the epidemiology of Haematopinus quadripertusus
* Up to 4.5mm long
* Location: mainly on the tail byt also around the eyes and ears
* Present in tropical QLD and likely in NT, WA
40
How to control lice
* Lice infestations are usually supressed in herds that are regularly treated for flies, ticks ect
* Generally the insecticides are not active against eggs -\> depending on the residual activity of the particular products repeat the treatment after 10-14 dyas
* Treat late autumn/early winter to prevent the development of heavy infestations
* Treat all cattle on property
