Respiratory Flashcards
BRD - bovine respiratory disease
Respiratory disease in cattle - multifactorial - pathogens, environment, management
varied pathogen involvement
Shipping fever
Groups post weaning (6m - 2 years)
M.haemolytica - mostly, can be others
Following transport, mixing groups, sudden diet cahnge
IBR - infectious bovine rhinotracheitis
What is it
Mild, subacute, acute disease
Alpha herpes virus - BHV-1
Gamma herpes virus - BHV-4 and OHV-2
Highly infectious and contagious
Endemic
Aerosol (3mile)
Direct contact or shared airspace
10-20 day incubation
Latent infection - for life
Recrudscence and shedding after stress - calving, movement, illness, corticosteroid use
Mild disease - conjunctivitis, epiphora, mild or immunity
Subacute disease - milk drop, pyrexia 40C, nasal discharge and hyperpnoea
Acute disease - growing cattle marked pyrexia, secondary infection, purulent nasal discharge and conjunctivitis
> 6m age usually
Worse in growing ages
Clinical signs of IBR
Diagnosis
High morbidity (100%)
Very high fever and death in 24 hours
Secondary bronchopneumonia
Abortion - up to 100 days after respiratory signs
Genital lesions - IPV - infectious pustular vulvovaginitis
Conjunctivitis, epiphora, milk drop, pyrexia, nasal discharge, hyperpnoea
Diagnosis
History and clinical signs
- New animals, clinical signs in multiple animals
Nasal and conjunctival swabs
PCR
Rising titres on ELISA
Bulk milk antibody test - exposure of herd
Controlling and eradicating IBR
Vaccinate to control clinical signs - intranasal to give IgM mucosal immunity for 60 days
Different vaccination schedules - depend on biosecurity
Accreditation schemes for IBR
Accredited free
Vaccinated monitored free
Eradication programme
Live vs inactivated
Other control measures
Accredited free - 2 qualifying tests and regular monitoring - milk/blood. Requires double fencing
Vaccinated monitored free
- 2 qualifying tests and regular monitoring - milk/blood
- Vaccinated with marker vaccine
- No requirement for double fencing
Eradication programme
- If no. +ve animals low - removed from herd
- If not possible - herd vaccinated with marker vaccine and enter VMF (vaccinated monitored free)
Live - rapid protection, esp intranasally
Inactivated - may reduce shedding in latently infected animals - high bulk milk Ab
Control
- Nose to nose contact
- Biosecurity - double fence
Do not buy in stock or test and quarantine
Malignant catarrhal fever
Aitiology
Clinical signs
Diagnosis
Treatment/control
OvHV-2 - sheep carry without showing clinical disease
Stress increases viral shedding - shearing/lambing
Sporadic disease not outbreaks
Aerosol, direct contact, contaminated feed/water/bedding - no cattle to cattle
Clinical signs
Pyrexia,
enlarged lymph nodes,
mucopurulent nasal and ocular discharge,
corneal opacity,
sloughing of oral and nasal mucosa
Treatment - MCF is almost always fatal - no licenced treatment or vaccine
Bovine TB
Routes of infection
Clinical signs
Ingestion - outside, or inhalation - housed
- Excreted in urine, sputum, faeces, milk (calves), exhaled air, vaginal and uterine discharge
Cattle to cattle spread, badgers, wildlife, contaminated slurry
Clinical signs
- testing eliminates most possibility of seeing clinical disease
Soft productive cough - worse if exercised or pharynx palapted
Weight loss, LN enlargement
- Mastitis with udder induration
TB testing protocol
SICCT
Blood testing - gamma, Ab
Post mortem
SICCT - avian and bovine tuberculin
- Measure skin thickness before and 72 hours post tuberculin
Specificity - 99.98%
Sensitivity - 50-80%
- False negatives
Blood
- IFN gamma - Sp 96.5, Sn - 90% - less false negatives, more false positives
- Ab test - Sp 98%, Sn 65% - Less false negatives than SICCT
Post mortem - all cattle inspected - reactors or restricted herds more detailed inspection
Preventing bTB
Pre/post-movement testing, use map, isolate animals
Wildlife proofing, secure feed, dig fencing down, raise troughs
Store slurry for long time, or 2m prior to grazing, avoid sharing equipment
Contagious bovine pleuropneumonia - CBPP
Aitiology
Clinical signs
Control
Mycoplasma mycoides
Eradicated from UK
Aerosol transmission. Poor patency in environment. Carriers once recovered
Pyrexia, incr respiratory rate and effort
Polyarthritis in affected calves
Notifiable in england. Vaccinate in other countries
Mycoplasma bovis
BRD, arthritis and mastitis
Present in respiratory tract of healthy animals
Chronic pneumonia, head tilt, ear droop, head shake
Diagnosis on serology/PM - joint tap, milk
Transmission - direct contact or fomite
Doesnt survive well in environment
Colostrum and intrauterine transmission
No vaccine
Emerging resistance to tetracyclines and macrolides
No cell wall so no penicillins
Mannheimia haemolytica
Pasteurella multicide
Respiratory
Gram negative, aerobic bacteria
Commensal of URT
Sporadic disease or outbreaks
M. haemolytica - Primary cause or secondary invader, disease tends to be more severe
P. multicide - secondary invader, disease less severe
Fog fever
Disease of sparse to lush high protein pasture
L-tryptophan converted to 3-methylindole - pneumotoxic
High mortality - sudden death
Severe respiratory distress without coughing or pyrexia - main differentials - lungworm and RSV (Bovine respiratory syncytial virus)
Prevention
- Introduce to lush pasture slowing or graze before lush
- Graze youngstock rather than adults - less common in young
Dictocaulus viviparus
Spread
PPP
Clinical signs
Test
Immunity
Spreads with Pilobulus fungus - translocates L3 out of pat and to herbage surrounding
Fomites - move larvae over large areas
Pre patent period 8-25 days
Decreased survival in hot, dry weather and short sward height
Larvae activated by bile, through SI wall, lymphatics, thoracic duct, lungs - 7 days
Lungs - growth to adult - 3-4 weeks
Migration - inflammation - eosinophils and mucus
Mild - cough intermittently, when run
Moderate - frequent bouts of coughing at rest, tachypnoea, hyperpnoea. Crackles at posterior lung lobes on auscultation
Severe - tachypnoea, dyspnoea, air-hunger position, tongue out when coughing. Sudden death
Host response -
Within 2 weeks of infection - immune response to destroy larave - short lasting immunity - type 2 innate immune - 6 month
Second immune response when reach lungs - 2 years or more
Test - baermann
