Respiratory Disease in Pigs Flashcards
Consider how respiratory disease impacts production in pigs?
- Morbidity and mortality
- Treatment/veterinary costs/need for vaccination Reduced growth rates/increased days to slaughter Reduced FCE (energy into immune system)
- Variation in supply –growth rates, back fat
- Penalties at abattoir –slow line, increased trimming Assurance schemes/market (multiplier)
- Environmental impact-more food, slurry, antibiotics
Virtually all resp disease in pigs is multifactoral?
- Bacterial/mycoplasma
- Viral
- Parasitic
Secondary bacterial infection of lung tissue already compromised by primary pathogens frequently occurs often more than?
- One agent involved
- Often highly contagious
- Spread by direct or aerosol contact
- Or indirect via birds and vehicles
What are pigs defences against respiratory pathogens?
- Nasal chambers
- Turbinates create turbulence
- Changing airway diameters alter speed
- Mucociliary apparatus
- Cough reflex
- Pulmonary alveolar macrophages
- Neutrophil invasion
- Antibody production (airway IgA, alveolar IgG)
Respiratory disease is?
Multifactorial –rarely solved with just a vaccine or one piece of management
What are the factors of effecting respiratory disease?
- Environment
- indoors, intensive, airspace, ventilation, chilling, age of pen mates, hospital facilities, contact with other animals
- Management
- Farrowing/MDA, moving/mixing/transport, nutrition/weaning, castration/other stresses, vaccination, contact with other pigs (mixed age groups)
- Breed and age
- Exposure to pathogens
Discuss damaged defence mechanisms?
Defence mechanisms overcome by overwhelming levels of infection, poor immunity, poor management, adverse environmental factors and the presence of other diseases
Filtration
- Damage to nasal chambers
Mucociliary apparatus
- Cilia damage
- Mucus viscocity
Phagocytosis
- Viral damage of macrophages
- Hypoxia induced reduction of macrophage oxidative phosphorylation
Clinical signs of respiratory disease in pigs?
- Coughing (often 1 st thing noticed)
- Dyspnoea +/-hyperpnoea
- Snuffling sounds (nasal obstruction)
- Heart failure and corpulmonale (severe/chronic)
- Pleurisy
- Anorexia
- Ocular discharge
- Sudden death
How do you diagnose respiratory disease in pigs?
- History and CE/observation may provide tentative diagnosis
- Clinical examination often limited
Brief auscultation may be possible and increased lung sounds may be evident:
- Wheezing
- narrowed airways
- Bubbling sounds
- blocking of bronchioles
- Squeaking sounds –pleuritic
- Harsh rubbing sounds –pleurisy
- This must be confirmed with lab tests/PME
- Abattoir surveillance data may indicate current diseases – this is important in pigs! Feed back from the abattoir to the producers
- Remember mixed infections!
What pathogens are noted by APHA as causing respiratory disease in pigs and what is the prevelance?
Pneumonia (not specified)15%
Swine influenza 16%
PRRSv 13%
Actinobacillus pleuropneumoniae 12%
Pasteurella multocida 11%
Mycoplasma hyopneumoniae 11%
Haemophilus parasuis 6%
Bordetella bronchiseptica 5%
Atrophic rhinitis (tox. P. multocida )0% -rare diagnosis these days
Outline respiratory diseases in pre-weaned pigs?
- Progressive atrophic rhinitis
- Bordetella bronchisepticum
- Inclusion body rhinitis (pig CMV)
-
PRRSv (reproductive and respiratory syndrome virus).
- Endemic and an issue worldwide
- Enzootic pneumonia ( Mycoplasma sp)
- Glassers disease ( Haemophilus parasuis ).
Bold –most prevalent
What are resp diseases in weaners, growers and fatteners?
- Bordetella bronchiseptica
- Glassers disease
- Actinobacillus pleuropneumonia
- Pasteurella multocida
- Mycoplasma hyopneumonia (EP) / hyorrhinis
- PRRSV
- Porcine respiratory coronavirus (PRCV)
- Influenza
- PMWS?/PCVAD
- (Aujeszky’s disease (pig herpesvirus 1))
Bold most common
Significant respiratory disease in non-immune adult pigs name ones prevalent in the UK?
- Glassers disease
- Actinobacillus pleuropneumoniae
- Pasteurellosis
- Enzootic pneumonia
- PRRSV
- Influenza
Discuss progressive atrophic rhinitis?
- Worldwide distribution, mainly intensive units
- Less of a problem in recent years –better management
- Toxigenic Pasteurella multocida in association with Bordetella bronchiseptica
- Colonisation of nasal mucosa by B.b with production of cytotoxin –allowing P.m to invade
- PM damages osteoblasts with osteolytic toxin and enhances osteoclast activity
What are the clinical signs of progressive atrophic rhinitis?
- Usually seen at 3-9 wks age
- Sneezing, nasal discharge/h+, facial deformity later
- Reduced growth rates and increased risk of pneumonia
What can be seen here?
Nasal deformity twisted snout from progressive atrophic rhinitis
How can nasal deformity from progressive atrophic rhinitis be graded?
How is progressive atrophic rhinits diagnosed and treated?
Diagnosis
- Causal organisms can be cultured from nasal swabs, serology for B. bronchiseptica .
- PME –Section snout at level of 2 nd premolar –
- damage to turbinates assessed on 0 (no damage) -5 (severe) scale
Tx:
antibiotics may help if early
Vacc: sows 2-6wks before farrowing
Control: Depop-repop with AR-free stock, strategic medication if CS, screening herds with ELISA for B. bronchiseptica
Discuss Bordetella bronchisepticum?
- Found in most pig populations
- Generally mild, self-limiting rhinitis (non- progressing)
- Therefore, clinically and economically of little importance
- Only a problem when in combination with toxigenic Pasteurella multocida .
What is inclusion body rhinitis?
- Porcine Cytomegalovirus (herpesvirus)
- >90% UK herds affected
- Transmission pig-pig or aerosol
- Mostly young pigs but outbreak in naive herd may affect all ages
What are the clinical signs, diagnosis and control of inclusion body rhinitis?
CS:
sneezing, serous nasal discharge and brown ocular discharge, high morbidity, low mortality
Diagnosis:
ELISA, inclusion bodies from nasal swabs
Control:
Maintain closed herd, protect suckling pigs from exposure
Discuss PRRS?
PRRS virus –Arterivirus
- Virus replicates in and destroys macrophages and endothelial cells → vasculitis
- Mixed infections with other resp pathogens very common
What are the clinical signs, treatment and control of PRRS?
Clinical signs
weaned pigs, mild coughing, sneezing, tachypnoea, innapetence, increased mortality
Tx:
in-feed/water antibiotics to cover period at risk – to reduce secondary bacterial infections (usually 6-8 wks)
Control:
early weaning off-site to break cycle, review pig flow, consider partial dep-pop of 1 st and 2 nd stage housing, vaccination
What can be seen here?
PRRS
With regards to PRRS once over the outbreak stage the signs can be controlled by?
Vaccination:
- Modified live (avoid in pregnant)
- Killed (breeders)
- Use in breeders and growers
Stabilise infection:
- Expose gilts / vaccinate prior to breeding.
- Stream grower pigs in separate airspaces.
Eradication:
- Stabilise sow/gilt infection and then depopulate all exc sows.
- Wean off-site to rest buildings for period.
Depop-repop:
- Infection transmits up to 3km
- Purchase uninfected stock and quarantine / test at isolation.
- Purchase uninfected semen.
Discuss enzootic pneumonia?
- Great economic importance
- Clinical disease, food conversion, weight gain
- 30-80% pigs have lesions at slaughter
- Mostly caused by Mycoplasma hyopneumoniae with frequent superimposed infection, esp. Pasteurella multocida
- Spread pig-pig mostly, also aerosol and wind (2 miles)
- Multifactorial –housing, temperature, humidity, mixing different ages/sources, overcrowding, continuous throughput systems
- Immunity short-lived, no colostral transfer
Look at this with regards to enzootic pneumonia?
Discuss M. hyopneumoniae?
- Weaned pigs
- ↑coughing –non-productive, worsened by exercise (when you walk around the pen you will really notice it)
- ↓FCE -<14% (feed conversion efficiency)
- Variance in growth -17% reduction in DLWG
- 2º infection
Look at this with regards to M. hyopneumoniae?
What is M. hyo lung scoring?
- Performed at abattoir as part of pig health scheme
- Report back to the farmer
- Some evidence for the lobes affected to do with the disease
What is this?
Glasser’s disease
What is this typical of?
Actinobacilus pleuropneumoniae (APP)
Typical target appearance infarct lesions
Dark haemorrhagic lesions
What is this?
Swine influenza particularly bad
What is this case study a strong indication of?
- # 1
- Medium-sized, single-site unit
- Various buildings for breeders, nursery and finisher pigs
- Farmer often brought-in extra breeder pigs and weaners from nearby farms
- Good medication/vaccination protocols and good ventilation
- Following a long period of cool and cold weather, the farmer noticed that numerous nursery pigs (4-7wks just been weaned) were dull and had ocular/nasal discharges and were often sneezing
- The problem seemed to be spreading to other buildings
- On inspection, 10-40% of the pigs in each nursery building were affected. The nasal discharges were pale white and mucoid/watery.
- A few pigs died and were PM’d –mucoid exudate in trachea and bronchial tubes with scattered irregular areas of form dark purple consolidation in the front lung lobes
Swine influenza –classic history
- Strong inflammatory reaction in the linings of the upper respiratory tract
- Requires close contact to spread as doesn’t form long- standing infection
- More common in autumn/winter and in ‘open-herds’
- Groups of affected pigs placed in warm, well ventilated areas and nursed until recover
- Consider vaccination of sows as MDA will block vaccines in piglets. Match vaccine with serotype present on farm
- Aim to reduce pig movements and avoid mixing of different groups.
- Do not be afraid to but euthanasia in the exam!
What is this case indicative of?
- Medium-sized breeder, nursery and finisher farm –older buildings, single site
- Often purchased gilts and pregnant females from other smaller farms
- Minimal medication and vaccination
- Farmer noticed several groups of nursery pigs had sneezing and nasal discharges
- Close inspection –numerous pigs 6-12wks old were snorting and sneezing. Serous to thick mucoid nasal discharge, some blood
- Also ocular discharges and difficulty closing mouths properly
- Poor growth evident and deformed snouts evident in chronic cases
Progressive atrophic rhinitis
- Disease now rare due to effective vaccines and breeding programmes for certified-free gilts
- Disease now mainly seen on older farms where piglets are derived from various sources of non- vaccinated gilts and then mixed together
- Affected pigs can be treated with Abs e.g. amoxicillin, to control the two bacteria.
- Vaccination to control in future and consider restocking with certified-free pigs to eradicate
Look at these vaccines?
What is this case study indicative of?
- Medium-sized breeder, nursery and finisher farm –old and new buildings, single site
- Minimal medication and vaccination
- Farmer noticed over 1yr, many grower pigs developed dry, persistent cough
- Seemed worse in older buildings
- Closer inspection indicated approx. 10% pigs affected at 10-20wks old
- Cough was a deep sound, chronic, non- productive
- No major increase in mortality but some pigs were slow to get to slaughter weight
Ezootic pneumonia ( M. hyo )
- Disease is usually worse in poorly ventilated, older buildings
- Always worth examining lungs at PM/Slaughter as tests not always reliable
- Case study typical scenario although more severe signs can be seen if introduced to naive herd
- Groups of affected pigs paced into a warm, well ventilated area and treated with appropriate Abs e.g. tylosin, tiamulin or lincomycin
- Could also treat other ‘at-risk’ groups with in-feed Abs
- Consider vaccination at 3-4wks old
- Look at ventilation, AIAO, depop/partial depop •Repop with certified-free pigs
What is this case study indicative of?
- Large nursery, grower and finisher farm
- Variety of older buildings
- Young nursery pigs arrived in batches from one modern breeder farm
- The farmer noticed many of the older finisher pigs were coughing and had a poor growth rate
- On closer inspection, many finisher pigs had developed a dry, harsh, persistent cough
- Lethargic, especially large groups in older buildings
- High mortality rate ~5%
- PME revealed dark black haemorrhagic patches in front and rear lobes of lungs, also dark metallic sheen and pleurisy
Actinobacillus pleuropneumoniae (APP)
- At least 12 serotypes with range of severity seen
- This case was a more chronic form
- Treatment of affected pigs with injectable Abs e.g. florfenicol
- APP not easily removed from all pigs using medication/vaccination
- Eradicate with de-pop, re-pop, wean piglets at 10d and move to separate unit
- Name antibiotics in exams!
