Infectious Diseases Flashcards
CA02; CA9-10; CA20-22; CA12-13; CA23-24
name 4 clinical signs of acidosis
- mental obtundation
- decreased suck reflex
- muscle weakness
- gut stasis
name 4 clinical signs of dehydration
- skin tent
- enopthalmos
- cold extremities
- tachycardia
how much oral fluids should be given to a dehydrated calf?
1-2L every 4-6h
what is the maintenance rate of IV fluids for a calf
5mL/kg per hour
what molecule should oral fluid therapy contain in order to treat a calf with acidosis
bicarbonate
(or one of its precursors)
what is the degree of acidosis?
alert and standing;
no skin tent or enopthalmos
no acidosis
what is the degree of acidosis?
standing securely;
enopthalmos
mild acidosis
(base deficit about 10mmol/L)
what is the degree of acidosis?
tired or listless;
wobbly;
aid to stand
moderate acidosis
(base deficit about 20mmol/L)
what is the degree of acidosis?
comatose or obtunded;
sternal or lateral recumbency;
impaired palpebral reflex
severe acidosis
(base deficit >20mmol/L)
what is the equation for the total base replacement (mmol) by IV therapy for a calf with acidosis
total base replacement = body weight (kg) x base deficit (mmol/L) x distribution of bicarb in the ECF (0.7 L/kg)
name the type of IV fluid
contains lactate (which is metabolised to bicarb);
mix of D-lactate & L-lactate;
calves cannot fully utilise D-lactate so less bicarb is produced;
not ideal but can help if all you have
Hartmanns
what is the most prevalent (infectious) cause of diarrhoea in a calf <7 days old
bacteria
(LESS acidotic than older calves)
what is the most prevalent (infectious) cause of diarrhoea in a calf 7-21 days old
virus
(usually acidotic)
what is the most prevalent (infectious) cause of diarrhoea in a calf >1 month old
parasite
(not acidotic)
what 4 causes of diarrhoea does a calf side scour SNAP test diagnose
- E coli
- Rotavirus
- Coronavirus
- Cryptosporidia
name the infectious cause of diarrhoea in calves
multiplies and releases enterotoxin which upregulates chloride secretion, increases osmotic potential of GIT contents so water is drawn into the lumen causing secretory diarrhoea;
rapid dehydration through faecal fluid loss and decr. fluid intake due to anorexia
E. coli
name the infectious cause of diarrhoea in calves
replicates in epithelial cells of small intestinal villi;
destruction of mature enterocytes in the villi;
secretion of a viral enterotoxin and atrophy of sm. intestine villi & colonic crypts causes malabsorptive diarrhoea leading to dehydration and acidosis
rotavirus
what 3 pathogens is Bovilis used to vaccinate against (active immunisation of pregnant cows and heifers to raise Abs against them)
- E. coli
- rotavirus
- coronavirus
name 2 treatment options for Cryptosporidia
- Parofor crypto
- Halocur
name 2 ways to diagnose coccidiosis
- McMasters
- Sporulation (for species)
name 2 treatment options for coccidiosis
- Diclazuril (Vecoxan)
- Toltrazuril (Baycox)
name 3 common bacterial/viral causes of diarrhoea in an adult cow
- Johne’s
- Salmonella
- Winter dysentery
what are the 3 main differential diagnoses for winter dysentry in adult cattle
- salmonellosis
- dietary upset
- SARA
what is the treatment for winter dysentery in adult cattle
symptomatic
(usually resolves with no treatment)
what is the most common type of Salmonella in UK cattle?
also causes abortion; NOT zoonotic
Salmonella Dublin
this is a common type of salmonella that causes salmonellosis in cattle and IS zoonotic
Salmonella Typhimurium
name 4 main ways Salmonella gets into a farm
- bought in animals
- slurry spreading
- vermin/birds
- vets & other visitors
what age of calves (mainly) are affected by Salmonella
2-6 weeks
what is the name of the vaccine used to prevent/control Salmonella (killed/inactivated vaccine for S. Dublin & S. Typhimurium);
reduce shedding and help protect in-contacts by reducing environmental contamination
Bovivac S
name the term
the study of how often disease occurs in different groups of animals and why
epidemiology
name the term
a disease which is consistently present in a particular population or region
endemic disease
name the term
an infectious disease that does not normally occur in a particular region
exotic disease
this is the average number of secondary cases produced in a naive population from one infectious individual
R_0
in endemic disease, what does R_0 usually equal?
1
what must R_0 be in order for an infection to spread in a naive population?
R_0 > 1
what are the 4 pillars of / what 4 things does the health status of any herd depend on?
- Biosecurity
- Surveillance
- Immunity
- Biocontainment
name the pillar of herd health status
risk of disease entering a herd;
depends on disease mode of transmission, farm biosecurity, buying history and geographical situation
biosecurity
name the pillar of herd health status
on farm - do we know what diseases are circulating on farm?
depends on current testing and scheme membership
surveillance
name the pillar of herd health status
on farm - depends on current and historical disease circulation, vaccination history and herd origin
immunity
name the pillar of herd health status
risk of disease spreading on farm;
depends on housing and management practices
biocontainment
where/what does Leptospirosis infect cattle through
mucous membranes
where does Leptospirosis localise following infection through mucous membranes
- repro tract
- kidneys
- udder
how is Leptospirosis spread/transmissed
infected urine
name 4 risk factors for Leptospirosis in cattle
- co-grazing with sheep
- shared water courses
- open herd
- shared bulls
how long can infected cattle remain hosts of Leptospirosis for?
years
what are the 3 main clinical signs of Leptospirosis in cattle?
- milk drop
- abortion
- infertility
how to diagnose Leptospirosis on a herd level?
bulk milk ELISA
what is the treatment for Leptospirosis?
Pen Strep
(Oxytetracycline or amoxyxillin also effective)
name the 2 vaccinations for Leptospirosis in cattle
- Spirovac
- Leptavoid-H
name the 3 official control programmes for Leptospirosis in cattle
- Accredited Free programme
- Monitored Free Programme
- Eradication Programme
what protozoan parasite is one of the most important cause of bovine abortion?
Neospora
what is the definitive host of Neospora?
dogs
name the two forms that Neospora exists in
- Tachyzoite
- Bradyzoite
name the form of Neospora
actively multiplying stage that migrates through the body in the acute stage of infection
tachyzoite stage
name the form of Neospora
part of the chronic infection when the parasite persist within the cell in tissue cysts
bradyzoite stage
this can occur when bradyzoite stage of Neospora are reactivated to the tachyzoite stage and spread throughout the body again
recrudescence
name the 2 most important transmission routes of Neospora in herds
- abortion storm (outbreak - dog horizontal)
- endemic abortions (cow vertical)
what does vertical transmission of Neospora ocurring in mid to late gestation result in?
persistently infected calf
what does horizontal Neospora infection early in pregnancy in cattle result in?
abortion
name the 3 main risk factors for neospora transmission in cattle
- contact with dog faeces
- persistently infected (PI) cattle
- buying in infected cattle
is there a treatment or licensed vaccine in the UK for Neospora?
no
name the 2 way approach to reduce transmission risk of neospora in cattle
- test & cull cattle (diagnose)
- management (prevent exposure/contact)
name 4 reasons for limited options of control programmes for neospora in cattle
- sporadic incursions
- persistent infection
- low diagnostic sensitivity & few clinical signs
- no vaccine or treatment
what does DIVA stand for in terms of diagnostic pathogen testing
Differentiate Infected from Vaccinated Animals
this is the ability of a test to correctly classify animals as positive
(false negatives)
rule OUT the diagnosis - high this means few false negatives
sensitivity
this is the ability of a test to correctly classify animals as negative
(false positives)
rule IN the diagnosis - high this means few false positives
specificity
what pathogen causes Johne’s disease
Mycobacterium avium subspecies paratuberculosis (MAP)
when does clinical disease of Johne’s disease typically occur in cattle?
3-5y of age
(neonatal infection)
what is the primary transmission of Johne’s disease
faeco-oral
(calf infected from dirty teats, contaminated milk, etc)
where does Johne’s disease localise after ingestion?
gut
what type of cell takes up MAP (Johne’s disease pathogen) intracellularly where it can remain latent for years until a stress event?
macrophages
what is the post-mortem pathology of Johne’s disease
chronic granulomatous enteritis
(thickening of intestinal wall, enlarged LNs)
what condition (clinical signs) does the clinical pathology of Johne’s disease result in
protein-losing enteropathy with subsequent hypoalbuminaemia
(weight loss, diarrhoea, oedema, bright demeanour and good appetite)
name the 4 main risk areas of Johne’s disease spread on farm
- infected adult cattle
- management at calving
- management of colostrum and milk
- young stock management
name the two way approach to reduce transmission risk of Johne’s disease
- test & cull
- management
what testing should be done in beef cattle herds for Johne’s disease
screen breeding animals > 2y
(don’t forget the bull)
what testing should be done in dairy cattle herds for Johne’s Disease
bulk milk / cull cow screen / targeted 30 cow screen
(quarterly testing)
name the 6 strategies to control Johne’s disease within dairy herds outlined in the National Johne’s Management Plan (NJMP)
- biosecurity protect and monitor
- improved farm management
- strategic testing
- test and cull
- breed to terminal sire
- firebreak vaccination
this should outline the disease status of the farm identifying the key challenges and areas of risk;
provides a framework for disease prevention strategies, such as vaccination, outlines how existing issues are to be tackled and measured, and monitors animal health and productivity
herd health plan
name the CHeCS 5 steps to controlling or eliminating disease
- establish herd disease health status
- decide if you want to prevent, manage or eradicate disease
- implement a protocol that will help achieve your goal
- monitor progress
- reassess disease status
name the 2 distinct forms (biotypes) of Bovine Viral Diarrhoea Virus (BVDV)
- cytopathic form (cpBVD)
- non-cytopathic form (ncpBVD)
what are most losses from BVDV associated with
loss of production
what is the main source of BVDV?
viraemic cattle
(usually exposed to a PI or transiently infected animal)
when must a calf be infected by BVDV in order to become persistently infected
in-utero prior to immunocompetence (<110 days)
what disease might a calf persistently infected with BVDV eventually succumb to
Mucosal Disease (MD)