Term
| Tell me everything about Chlamydophila pecorum |
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Definition
Occurs in large, rapidly growing lambs. Causes bacterial arthritis. It is most common in weaned lambs, though it has infected lambs as young as 2 weeks old.
It is though to be transmitted through the flock by consumption or inhalation of infected material in the faeces, urine or ocular discharges. The bacteria can also enter through the conjunctiva. It mostly affects lambs at 3-6 months of age |
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Term
| What are the clinical signs associated with Chlamydophila pecorum? |
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Definition
| The lambs become stiff, pyrexic, lame and may be reluctant to move. They may also develop conjunctivitis. The joints contain cloudy synovial fluid, but are not always swollen. |
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Term
| How successful is the treatment of Chlamydophila pecorum? |
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Definition
| If treated early (with antibiotics) treatment is often successful, though if the infection is caught late, then damage to the joint may be permanent and although the infection may be resolved, the lamb will stay lame. |
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Term
| How can you prevent infection with Chlamydophila pecorum? |
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Definition
| Ensure the lambs are in a paddock with a low level of faecal contamination. |
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Term
| What do you know about the epidemiology and route of infection of Histophilus ovis? |
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Definition
| It is fairly rare causative agent of arthritis in sheep. Lambs are most likely to become infected soon after birth (infection enters by the umbilical cord), at marking (ear marking, tailing, castration), at mulesing, after shearing (cuts), sheep being held in yards after shearing/mulesing, any time when the skin is broken or wet. |
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Term
| What are the clinical signs associated with Histophilus ovis? |
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Definition
| Swollen, painful hocks, lameness, weight loss |
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Term
| Why does Histophilus ovis cause weight loss? |
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Definition
| The sheep are lame and therefore have resuced feed intake cos they can't get to it. |
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Term
| What do you know about the epidemiology of Scabby mouth? |
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Definition
it has a world wide distribution and is thought to be the most common viral disease of sheep in Australia.
It affects sheep of all ages, though it is seen less commonly in older animals due to the infection giving the sheep full immunity (causing a lower incidence of sever disease) |
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Term
True of false:
Scabby mouth is not zoonotic |
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Definition
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Term
| What are some other names for Scabby mouth? |
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Definition
| Orf, contagious ecthyma, contagious pustular dermtitis |
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Term
| WHich family of viruses does Scabby mouth belong to? |
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Definition
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Term
| How does Scabby mouth enter the body? |
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Definition
| Damage to the skin or mucosa is essential, infection can occur from direct contact with scabs (ew) or infected animals. |
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Term
| What are the clinical signs of Scabby mouth? |
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Definition
2-4 days post infection , the skin becomes reddened and may show some swelling
The first signs are often seen at the corners of the lips. The reddened area then evolves into pustules which rupture and cause the characteristic scab.
The scabs lift in 1-2 weeks, leaving the skin raw which then heals quickly. |
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Term
| What can happen in severe cases of Scabby mouth? |
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Definition
| Sometimes the scabs can spread and merge, causing the infection to involve the entire face, as well as the oral cavity and tongue. These lesions usually take 4-6 weeks to disappear. |
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Term
| How are the majority of infections of Scabby mouth diagnosed? |
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Definition
The majority of infections are diagnosed through the visible clinical signs, history of the infection in the herd, vaccination history.
It is possible to diagnose the infection through ELISA. |
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Term
| How a infection of Scabby mouth treated? |
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Definition
| It's not. There is not 'cure' for the virus, and most infection will usually just run its course. |
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Term
| What are the risk factors associated with Scabby mouth? |
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Definition
Anything that damages the skin or mucosa.
So burrs and thistles are of large concern |
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Term
| What are the herd management strategies for Scabby mouth? |
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Definition
Vaccination
- Skin is scratched and live vaccine is introduced. If vaccination is successful, then small pustules form along those scratches (you make them on the inner thigh, or behind the elbow in pregnant ewes) 5-10 days later, and develop immunity 14 day post vaccination.
It is also useful to reduce the chance of skin cuts being made, so reducing the number thistles and burrs in the paddock, as well as watching out for cuts made during shearing. |
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Term
| When should you consider vaccination for scabby mouth? |
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Definition
| You should not consider vaccination for scabby mouth unless it has caused problems on that farm previously. If you vaccinate, you bring the virus onto the farm and you will need to vaccinate from them on in. |
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Term
| Which Mycoplasma causes arthritis and synovitis? |
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Definition
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Term
| Which Mycoplasma causes mastitis and arthritis? |
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Definition
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Term
| Which Mycoplasma causes can cause arthritis in calves vaccinated against bovine pleuropneumonia? |
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Definition
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Term
| Which Mycoplasma causes arthritis, septicaemia and pleuropneumonia in goats and sheep? |
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Definition
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Term
| What is the pathogenesis of Mycoplasma? |
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Definition
| Pre-existing respiratory infection in nearly always seen, the joint issues develop secondary to this |
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Term
| How can you test for Mycoplasma? |
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Definition
| Joint fluid culture on specific media is best. If M. mycoides is supected then serology on the fluid may be useful |
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Term
| How can you treat a Mycoplasma joint infection? |
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Definition
It is usually pretty unresponsive to treatment, though you can try enrofloxacin.
Prevention is better, so good biosecurity, reduction in stress, reducing transport. Standard things |
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Term
| What is the main causative bacteria seen in foot rot? |
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Definition
| Dichelobacter nodus, may vary in virulence |
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Term
| What is a less common cause of foot rot that exists normally in faeces? |
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Definition
| Fusocacterium necrophorum |
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Term
| How foes foot rot cause disease? |
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Definition
Under wet conditions, the interdigital space becomes macerated, allowing the bacteria to enter at the skin/hoof interface. By action of proteases liquefies the cells of the stratum granulosum and stratum spinosum, casuing the hoof wall to separate from the basal epithelium.
It works its way down to the heel and then across the sole, finally reaching the lateral side of the hoof |
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Term
| How long can D. nodus survive in the enviroment? |
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Definition
| I can survive <2 wks in the environment, but it can survive indefinitely in the cracks, crevices and deformities of infected hooves. |
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Term
| How many strains of D. nodus are there? |
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Definition
| Around 20 and they vary in virulence. |
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Term
| What weather favours foot rot spread? |
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Definition
Hot and wet conditions are best, though they can also spread in cold and wet conditions.
Basically, if it is not super dry, it is a goer. |
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Term
| If you were foot dipping to treat or manage foot rot what should you use? |
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Definition
| Trim the feet up first so that all of the infected horn is open to the air, and then use a 10% zinc sulfate solution, the addition of sodium laurel sulphate has been found to be really useful as it is a surfactant and breaks up grease. You can add it in the form of laundry powder. |
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Term
| Can you vaccinate for foot rot in AUstralia? |
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Definition
Yes, there is a vaccine called Footvax, but it only covers 10 serotypes. This, therefore, can not be used for prevention or elimination as it does not cover all the serotypes.
It can HELP with the prevention, but it should be noted that no immunity is acheived until after the 2nd dose. Vaccination should be repeated every 10-12 weeks while protection is needed |
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Term
| Where does Fusobacterium necrophorum come from? |
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Definition
| In most animals it is commensal bacteria of the gut |
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Term
| How is Fusobacterium necrophorum transmitted? |
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Definition
| Mostly through wound entry or naval entry |
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Term
| What are the clinical signs of joint infection with Fusobacterium necrophorum? |
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Definition
Lameness, reluctance to move, hot swollen joints, painful joints, suppurative arthritis of the hock, knee, stifle, elbow or shoulder
There may also be lesions such as abscesses in the liver or lungs |
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Term
| How does the animal become infected with Fusobacterium necrophorum and how does it cause disease? |
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Definition
Bacteria often enters through the unbilicus and begins to show signs of infection 2-7 days after birth. The infection may also enter through wounds such as mulesing or marking/Septicaemia often contributes to the haematogenous seeding of the joints with bacteria that localise in the synovial membrane.
Articular cartilage becomes damaged by bacteria proliferation and inflammatory processes causing fibrosis. |
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Term
| How is Fusobacterium necrophorum diagnosed? |
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Definition
| Post mortem sampling of the joint and then culture. |
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Term
| What bacteria cause ovine digital dermatitis? |
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Definition
| Fusobacterium necrophorum and the non-virulent strains of D. nodous |
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Term
| What else may ovine digital dermatitis be referred to by farmers? |
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Definition
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Term
| What are the clinical signs associated with ovine digital dermatitis? |
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Definition
Mild lameness (generally score 1), in severe cases interdigital skin may split leaving tissue exposed. There is usually mild interdigital hyperaemia and swelling.
There is no smell or under-running and there is minimal separation at the skin horn junction |
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Term
| What are the risk factors for OID in flocks? |
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Definition
The organism is ever present in the environment, so it just hangs around waiting for the right weather. Moisture is essential and heat is preferred.
Trauma from frost or mud is also a risk factor |
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Term
| What are the common treatments for OID? |
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Definition
Often resolves spontaneously when conditions in the dry, it can be treated with zinc sulphide footbaths.
Over night housing on hard, dry floors is often beneficial. |
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Term
| How do you determine between virulent and non-virulent foot rot in a flock? |
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Definition
- Presence of under running
- >1% of the flock having lesions score 4 or worse |
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Term
| What is a progression test for footrot? |
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Definition
Individually score 10-20 animal's feet (and record the scores for the animal and the foot).
Do not treat these animals and re score 10-14 days later. Look for progression of clinical signs |
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Term
| What are the three steps of a footrot treatment programme? |
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Definition
Control
- Footbathing
- Use Zn suplhate
- Cu sulphate is availabe, but takes more dryin time
- Foot paring can assist with making the foot bath more effective
Eradication phase
- Inspect all sheep feet, cull on a mob or individual level
- If high prevelance, consider depop of mob
- All suspect feet are classed as infected
- Reinspect in 3 weeks, and cull all infected
- biosecurity when introducing new stock
Surveillance
- Ensure and maintain biosecurity (fence imporant!!)
- Purchase only from clean flocks
- Inspect all new stock |
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Term
| How does foot scoring work? |
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Definition
It is based on visual inspection of each individual foot, and classifying it based on a 0-4 scale.
0 - no lesions, normal
1 - Non-specific inflammation and/or necrosis of the interdigital skin
2 - Inflammation of the IDS which is due to infection with footrot
3 - Any lesion in any claw which results in under-running of the soft horn of the heels or sole
4 - Under-running of the hard horn of the claw |
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Term
| Which bacterium cause suppurative joint disease? |
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Definition
F. necrophorum
A. pyogenes
H. ovis
Staph spp
Strep spp |
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Term
| Which agents cause non-suppurative joint disease? |
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Definition
Erysipelothric rhusiopathiae
Chlamydia psittaci |
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Term
| Tell me about actinomyces pyogenes |
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Definition
Often seen in neonates as a result of failure of passive transfer, in older sheep it is seen as a result of penetrating injury or from a nearby infection in tissue
It spreads tot he joint usually after septicaemis and then haematogenous spread to the joint. The bacteria localise and fuck up the synovial membrane |
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Term
| What are the clinical signs associated with actinomyces? |
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Definition
Lameness, warm and swollen joints (possible sever lameness leading to recumbancy)
Affected animals are often febrile and anorexic |
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Term
| How can you prevent infection with actinomyces? |
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Definition
| Ensuring passive transfer, maintain clean environment for lambing and provide adequate umbilical care |
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Term
| What do you know about E. coli in joints? |
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Definition
oppertunistic disease, associated with poop, present on skin, faeces anf in soil. Less common pathogen
often shows as a secondary foci of infection after other infection of e coli. |
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Term
| What are the clinical signs of joint infection with E. coli? |
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Definition
Lameness, recumbancey, ill thrift.
Chronic lesions - swollen and hot joints |
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Term
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Definition
Infection caused by dermatophilus congolensis.
It is beleived to be spread by direct contact between animals, through contaminated environments and biting insects |
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Term
| How does strawberry foot cause disease? |
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Definition
Zoospores enter through fucked up epithelium and germinate to form hyphae which penetrate into the epidermis and spread, causing an acute inflammatory reaction.
There is a natural resitance in the form of phagocytes, though once the infection is established, there is nothing you can do.
The infected area heal spontaneously , though infected follicles and scabs can cause re-infection of non infected hair follicles |
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Term
| What are the clinical signs associated with strawberry foot? |
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Definition
Circumscribed, heaped scabs that appear around the coronary band and lower limbs
The lesions usually coalesce |
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