Term
| What are the types of vaccines available? |
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Definition
| Live attenuated,inactivated, subunit/recombinant and DNA vaccines |
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Term
| Describe the primary and secondary response to vaccines |
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Definition
Primary - 2-3 weeks for naive cos to develop antibodies for pretection as the antibodies are derived from the division and multiplication of lymphocytes following exposure
Secondary - Re-exposure (following 1st booster)will lead to the lymphocytes encountering antigen. These lymphocytes (which have encountered the antigen before) then produce antibodies. The 2nd response is much faster and much more refined, working within hours of days rather than weeks |
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Term
| Which vaccine type does not often require a yearly booster? |
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Definition
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Term
| What is a live attenuated vaccine? |
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Definition
| A vaccine made from live bacteria or virus that has been modified through a process to weaken and reduce the virulence. |
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Term
| How is the tick fever vaccine attenuated? |
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Definition
| The virus is passed between immunologically naive and splenectomised calves |
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Term
| What are the issues with live attenuated vaccines? |
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Definition
| Possible return to virulence and disease causing |
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Term
| What are inactivated vaccines? |
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Definition
| Do not contain live bacteria or virus. They have been killed by chemicals, heat or radiation. They also stimulate a weaker immune response. |
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Term
| What is a subunit vaccine? |
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Definition
| A vaccine that does not use the entire microbe, but rather the section that causes the largest/most powerful immune response. |
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Term
| What is a conjugate vaccine? |
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Definition
| A vaccine made of the outer polysaccharide shell of an encapsulated bacteria |
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Term
| What is a toxoid vaccine? |
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Definition
| A vaccine developed from a toxoid rather than the whole bacteria, the toxoid can be inactivated with formalin |
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Term
| Which vaccinations require refrigeration? |
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Definition
| Live, subunit, toxoid and conjugate vaccines |
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Term
| What are some causes of vaccine failure? |
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Definition
Incorrect serotype or strain
Incorrect formulation
Incorrect or insufficient adjuvant
Incorrect storage
Incorrect preparation
Improper administration
Incorrect dose
Immunocompromised animals
Malnourishment
Poor enviromental ygiene |
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Term
| What are the advantages and disadvantages of using the frozen vaccination for tick fever? |
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Definition
Adv: - Protects against babesia bovia and bigemina as well as anaplasma marginale
- Can vaccinate cattle of any age
- Long ass shelf life (5 years when stored well)
Disadv: - has to be kept at -21 degrees (liquid N)
- Only dispatched on Fridays, just order 24hrs prior
- only comes in 25 and 100 dose packs |
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Term
| What are the advantages and disadvantages of using the chilled vaccine for tick fever? |
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Definition
Adv: - Covers same 3 pathogens as frozen
- Orders shipped on tuesdays and thursdays
- comes in 10, 20, 23, 50 and 100 dose packs
- Store at 2-8 degrees
- Can vaccinate at any age
Disadv - shorter shelf life
- $4.27/dose |
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Term
| How are the tick vaccines developed? |
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Definition
Parasitic blood is collected from calves with attenuated lab strains
Vaccine donor calves are housed in insect free air conditioned units
The calves are inoculated IV with one ot the lab strains and monitored daily
Blood is collected from calves when parasitaemia occurs
Parasitic blood is then diluted with sterile isotonic cell free diluent |
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Term
| What is endemic stability? |
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Definition
| An epidemiological state in a population in which clinical disease is scarce despite a high level of infection or where the relationship between host, agent, vector and environment is such that clinical disease occurs rarely or not at all |
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Term
| How does endemic stability relate to tick borne diseases? |
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Definition
| There is a high rate of tick infection in cattle (esp young cattle), though there is an absence of clinical signs as calves have an higher innate resistance to tick borne diseases. This means that they are able to develop immunity, leading to low incidence of clinical disease in adults |
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Term
| To what age do calves remain resistant to tick diseases? |
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Definition
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Term
| Where are ticks present in Australia and how is it limited? |
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Definition
Limited by legislation movement controls, Tick zones include the area east of the Great Dividing Range and north of the great northen rail line
They are also considered to be in the northen areas of WA and NT |
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Term
| What tick fever cause is the most common? |
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Definition
|
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Term
| How do you treat tick fever? |
|
Definition
Babesia - Imidocard @ 1ml/kg SC
Anaplasma - Imidocard @ 2.5ml/kg SC
Remove the ticks
Assess severity
Vaccinate all at risk animals
DO NOT VACCINATE TREATED ANIMALS
Monitor cattle
Protect rest of herd |
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Term
| What are the agents that can cause tick fever? |
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Definition
B. bovis
B. Bigemina
Anaplasma marginale
Theileria orientalis/ikeda |
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Term
| Which of the babesia are the most common in Aus? |
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Definition
| Bigemina, though bovis causes the most cases of disease as it is more pathogenic |
|
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Term
| Which of the tick fever agents is the most common worldwide? |
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Definition
|
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Term
| What are the host risk factors tick fever? |
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Definition
Bos taurus
Age (older animals are more resistant)
Seasonal variation |
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Term
| How do you identify types of what type of agent you have? |
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Definition
| Examination of a blood smear, you look at the RBCs, the protozoan can be seen within the cells |
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Term
| What is the incubation time for babesia bovis? |
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Definition
|
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Term
| How does B bovis cause disease? |
|
Definition
Over production of cytokines and other inflammatory agents causing vasodilation, increased capillary permebility, vascular collapse, coagulopathies
Infected RBCs aggregate in lungs and brain capillary beds |
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Term
| What is the incubation period for B bigemina? |
|
Definition
|
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Term
| What are the clinical signs of Babesia infections? |
|
Definition
High fever
Haemoglobin uria
Increased HR and RR
Jaundice and anaemia
Diarrhoea and rapid weight loss
Recumbency and coma
Possible abortion due to fever
Temporary infertility in bulls (due to fever) |
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Term
| How is anaplasma transmitted? |
|
Definition
In Aus - ticks
Other countries - ticks as well as biting flies |
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Term
| What is the incubation time for anaplasma? |
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Definition
| 3-4 weeks, though they remain carriers for life |
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Term
| How does anaplasma cause disease? |
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Definition
| Multiply by binary fission to produce 2-8 infective bodies which infect other RBCs. Parasitised RBCs are destroyed by the reticuloendothelial system, leading to a progressive anaemia |
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Term
| What are the clincial signs of anaplasmosis? |
|
Definition
Anaemia
fever
Increased HR and RR
No haemoglobinuria
Decrease in production
Pregnant cows abort |
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Term
| How is theileria transmitter? |
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Definition
| Bush tick (rather than cattle tick) |
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Term
| What is the incubation time of theileria? |
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Definition
|
|
Term
| What are the clinical signs of theileria? |
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Definition
| Lethargy, anorexia, exercise intolerance, pale, yellow gums, abortions or still borns |
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Term
| Is there a vaccine available for theileria? |
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Definition
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Term
| What supportive therapy should be considered for the treatment of tick fever? |
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Definition
| For anaplasma and babesia, blood transfusion is PCV <12%, if less than 8%, then treatment prognosis is decreased |
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Term
| How does natural immunity work to prevent tick fever? |
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Definition
- Colostrum provides protection for ~ 2 months
- Innate immunity covers the calf from 3-9 months
- Exposure to a tick burden from 6-9 months will usually cause no clinical signs and will result in long lasting immunity |
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Term
| Which breeds of cattle have a genetic resistance to tick fever? |
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Definition
| Bos indicus animals (an crosses that are >50% bos indicus) |
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Term
| What percentage of their time do ticks spend on the ground/pasture? |
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Definition
|
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Term
| How can you reduce the number of ticks in an environment? |
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Definition
| Pasture rotation/spelling is particularly useful as the tick requires a host |
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Term
| Can you use 'spot on' treatments to control tick fever? |
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Definition
| Not really, as the tickicide does not target the larval stage when the tick is most likely to transmit disease |
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Term
| What samples would you need to take to diagnose tick fever in a live animal? |
|
Definition
Blood (EDTA) - haematology (anaemia/presence of protozoa)
Blood (plain/clotted) - serology |
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Term
| What is the benefits of taking peripheral blood for testing for tick fever? |
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Definition
| There is a higher chance of detecting the organism in peripheral blood |
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Term
| What samples would you need to take to diagnose tick fever in a dead animal? |
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Definition
Fixed tissue - spleen, liver, bone marrow and brain
Blood/organ smears - peripheral blood, kidney(if fresh), heart muscle, spleen, liver, lung, brain
Decomposing animals - spleen, brain, heart muscle |
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Term
| How low is the number of circulating protozoa in general blood compared to peripheral blood? |
|
Definition
|
|
Term
| What is the life cycle of the cattle tick? |
|
Definition
Rhipicephalus (boophilus) microplus
Engorged female drops to ground and hides amongst plant litter
Lays eggs over a week in summer (longer in winter)
Eggs hatch into larvae at 2-21 weeks (depending on temp and humidity)
6-legged larvae climb up grass and other things and rub off on cattle as the walk past. They can also be wind blown for 20M
Larave attatch themselves to a host and feed for ~1 week
Then become nymphs for 1 week
They moult into adults and then mate and feed and stuff |
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Term
| When is the cattle tick most active? |
|
Definition
| Late spring to early winter |
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|
Term
| What does the cattle tick look like? |
|
Definition
Pale cream legs ( a wide distance from snout)
Oval/rectangular body |
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Term
| What are some of te effects of a heavy tick burden? |
|
Definition
Decrease in production
Decreased feed intake
Immunosuppression
Hide damage
Labour increases for treatment |
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|
Term
| What is the threshold for a 'heavy' tick burden? |
|
Definition
| 150-300 engorged ticks/cow |
|
|
Term
|
Definition
| A tickicide, does not affect the larval ticks, might decrease overall numbers though |
|
|
Term
| What is an example of an acaricide? |
|
Definition
|
|
Term
| In general, how often do you need to reapply acaricides? |
|
Definition
|
|
Term
| What's the problem with the buffalo fly? |
|
Definition
| They irritate the cattle, cause hide damage and transmit stephanofilaria worms |
|
|
Term
| How can you control the buffalo fly? |
|
Definition
Chemical control - self applicators (backrubbers and dusting appliances)
- Ear tags that slowly release organophosphates and synthetic pyrethroids
Non-chemical - flytraps
- Dung beetles
- Culling of highly affected cattle |
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|
Term
| For the purposes of tick control, how is Qld divided? |
|
Definition
Infected
Control
Free zones |
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Term
| What do you have to do if you want to move a cow from an infected zone to a controlled or free zone? |
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Definition
| They must be inspected, cleaned and treated under the supervivion of a Qld biosecurity officer. |
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|
Term
| To move cattle from Qld to NSW what must you do? |
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Definition
Ensure the cattle have a NLIS tag
Notify the NLIS database of the movement
Be treated and cleared free of ticks |
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Term
| What forms do you need to move stock in relation to tick areas? |
|
Definition
Qld travel permit
Qld livestock movement system - waybill or national vendor declaration
Cattle tick preliminary treatment - Owner declaration
Cattle tick cert of inspection and treatment |
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|
Term
| What is the longest you can transport a cow over 6 months old by land? |
|
Definition
| 48 hrs followed by a min spell of 36hrs |
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|
Term
| What is the longest you can transport a cow between 30 days and 6 months old by land? |
|
Definition
| 24 hrs followed by a min spell of 12 hrs |
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|
Term
| What is the longest you can transport a lactating cow by land? |
|
Definition
| 24hrs followed by a min spell of 12 hrs |
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|
Term
| What is the longest you can transport a calf 5-30 days old (w/o mum) by land? |
|
Definition
|
|
Term
| Can cattle be transported in the last 3 months of pregnancy? |
|
Definition
| Yes, but only when vital and signed off on by a vet |
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|
Term
| What are some considerations when moving stock between states? |
|
Definition
MUST HAVE AN NLIS TAG AND VENDOR DECLARATION!!!
Animal health statement is also good
Climate, temp, humidity, inclement weather
Disease
Vaccination
Age
Class (e.g. lactating, pregnant..)
Time off water
Distance
Stopping points
Type of terrain (actual speed possible by road) |
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|
Term
| What are some diseases of concern regarding interstate transportation of stock? |
|
Definition
Ticks
Johne's
Enzoontic bovine leukosis
Liver fluke
Foot rot |
|
|
Term
| What are some of the most common causes of anaemia in cattle? |
|
Definition
Abomasal ulceration
Bracken-fern poisoning
Acute blood loss
Parasitic diseases
Lepto
Clostridium novyi
Tick fever
Chronic Cu tox
Zn tox
Iron, Co, Cu, Se, Mg deficiency
Chronic liver disease
Pb poisoning |
|
|
Term
| What are some ddx of red urine in cattle? |
|
Definition
Bracken fern - on PM there is thickening and scarring of the bladder
Enzootic bovine pyelonephritis - Rectal exam (ureters and caudal pole of L kidney is often swollen and painful)
Post parturient haemoglobinuria - history, regen anaemia, no sediment on urin exam
Bacillary haemoglobinuria - sudden death, widespread hemorrhages on PM, characteristic single large liver infarct
Lepto - heard antibody titres, leptospired in urine or foetal kidney
Chronic Co tox - clinical signs, jaundice, gun-metal black kidneys
Babeisosis and therileriosis- clinical signs, exam of blood smear
Brassica - Clinical signs, history of exposure |
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