Pig respiratory system Flashcards
What is the typical agent that causes acute fibrinous necrotising pleuro-pneumonia
Actinobacillus pleuropneumoniae
What is the typical agent that causes chronic necrotising pleuro-pneumonia
Actinobacillus pleuropneumoniae
Typical agents causing embolic pneumonia (pyaemia)
Trueperella pyogenes
Staph aureus
What is the typical agent of disseminated broncho-interstitial viral pneumonia
Influenza
Typical agents causing viral interstitial pneumonia
PCV2
PRRSV
What is the causative agent of progressive atrophic rhinitis
Bordetella bronchiseptica
Toxigenic pasteurella multocida
What is the cause of catarrhal rhinitis
Influenza
What are the issues with selecting for good immune response genetics in pigs
Associated with poor growth and production
How does PRRSV have an immune-dysregulatory effect
Targets lung macrophages and kills them; this impacts both innate immunity and antigen presentation
What does porcine resp coronavirus cause
A mild cough
NB: this is a mutant from the much mores serious enteric form and gives cross protection
What bacteria are primary agents in pneumonia
Actinobacillus pleuropneumoniae
B bronchiseptica
What kind of pathogen is P multocida
= opportunistic pathogen; usually a commensal
Follows primary infection with influenza/mycoplasma/PRRSV
Signs and pathological lesions in pneumonic pasteurellosis
Small number of pigs (with secondary pathogen) showing coughing, inappetance, fever, low weight gain
Can get septicaemia and die if untreated
–> = some sick pigs against background of less severe disease (with primary pathogen)
Pathologically: consolidated patches of dependent lung lobes, mucopurulent exudate in airways
Some get interstitial nephritis due to immune complex deposition in chronic cases
Aetiology of actinobacillus pleuropneumoniae
Primary pathogen that adheres to tonsils and alveolar epithelium via pili and then can move down to lungs or pass to piglets
Produces haemolysins and cytotoxins and causes destruction of macrophages
Long term tonsil carriage in subclinical infection
Signs and lesions in actinobacillus pleuropneumoniae
Rapid onset fever, severe dyspnoea, coughing, sneezing, vomiting etc
Seen in piglets post-weaning; spread from those with mAb to susceptible pigs
Lesions = haemorrhagic with fibrinous pleurisy and necrotic centres in caudal or diaphargmatic lobes
How does serology for actinobacillus pleuropneumoniae work
Detects antibody against the apxIV toxin; but doesnt tell us anything about virulence of the strain
Can we eradicate actinobacillus pleuropneumoniae once on a farm
Very hard due to long term carriage in tonsils
Could buy serologically negative replacement stock
Significance of mycoplasma hyopneumonia
COmmon and mild but economically significant due to effects on growth rate and immunsuppression caused
Signs of mycoplasma hyopneumonia infection+ lesions/histopath
Widespread barking cough, variable growth rates in group, pigs still look bright
In 6 weeks to finishing age
Lesions = consolidation in dependent lobes; may see pneumonic pasteurellosis in top with P multocida (secondary pathogen)
Lymphocytic cuffing on histopath
Epidemiology of mycoplasma hyopneumoniae
Spreads via aerosol in damp cool weather
Pigs remain carriers
Immunity short lived so same strain can recirculate on farm
Vaccination how common
Which pathogen gives classic lymphocytic cuffing around bronchioles
M hyopneumoniae
Dealing with M hyopneumonia on a pig farm
Use in feed medication during outbreak (tetracyclins, tiamulin)
Vaccinate from a week old
What type of pathogen is Glaserella parasuis
Gram -ve bacteria
Usually a secondary pathogen
Lots of serotypes; some cause systemic infections via seeding through bloodstream
Clinical signs of glasserella parasuis
Typical at weaning
Resp disease: nasal discharge and coughing
Polyserositis: arthritis, meningitis, peritonitis
Septicaemia: swelling of face/ears - dead in days
Necropsy findings with glaserella parasuis
Fibrinous peritonitis, fibrin on chest wall and pericardium
Epidemiology of glasserella parasuis
Transmission from sow to piglet at young age, then petween pigs at weaning
Respiratory disease usually triggered by underlying viral infection
Treatment for glasserella parasuis
Parenteral antibiotics e.g penicillin for sick ones
Water mediation for rest of group; tetracycline, amoxycillin
Which serotypes cause systemic disease in glasserella parasuis
4, 5, 7
What disease does bordetella bronchiseptica cause
Non-progressive atrophic rhinitis
When toxigenic P multocida is involved too, get progressive atrophic rhinitis
Clinical signs and lesions with B bronchiseptica non-progressive atrophic rhinitis
Sneezing, coughing, mucopurulent nasal discharge, mild turbinate damage, mild snout deviation
+ bronchopneumonia in some cases
Catarrhal rhinitis, patchy lobular broncopneumonia in some cases i.e looks similar to influenza
Which tissues does swine influenza infect
Just respiratory tract (unlike in other species where there is gut replication too)
Clinical signs with swine influenza
Sudden onset coughing in all age groups, fever and inappetance, abortion in sows
Mortality rare
Moves through indoor unit very quickly
Lesions post mortem with swine influenza
Plum coloured lesions, dependent lobe consolidation
Bloody exudate in airway
How can pigs be a vehicle for zoonotic swine influenza
Pigs express both alpha2-3 gal and 2-6gal so they are susceptible to both avian (2-3) and human (mostly 2-6) influenza; potential for recombinatino and making new strains
What type of pathogen is PRRSV
= RNA virus arterivirus
What are the two forms of disease from PRRSV
Respiratory syndrome: contribution to multifactorial pneumonia –> blue eared pig disease in non-immune herds
Reproductive disease in sows: abortion, weak piglets, mummification etc
Aetiology of PRRSV
Transmission mostly aerosol but could get from semen, injection, fomites etc
Replicates within pulmonary alveolar macrophages, therefore killing them and causing immune dysregulatory effect
Prolonged viraemia then months of tonsil carriage
What might be called blue eared pig disease
Porcine reproductive and respitory syndrome virus
Why might we get some piglets alive and some mummified in PRRSV
Due to slow spread through uterus
Diagnosis of PRRSV
Gold standard is PCR on blood
Control of PRRSV
Modified live vaccine in breeding sows to avoid number of viraemic piglets born
Expose gilts to farm strains before breeding to stimulate immunity and good colostrum to piglets
Causative agents in catarrhal bronchopneumonia
Mycoplasma hyopneumoniae mostly
May have some strep, M hyorhinitis
What are heavy, rubbery non-collapsed lungs with oedema suggestive of
Interstitial viral pneumonia
e.g from PCV2, PRRSV
If we see pneumonic pasteurellosis cases what might we want to review the vaccination protocol of
PRRSV
Mycoplasma
(because P multocida = SECONDARY pathogen)
Which mycoplasma is a primary agent in pneumonia
M hyopneumoniae
How does mycoplasma hyopneumonia have an immune-dysregulatory effect
Stops cilia beating so lose muco-ciliary escalator
How does PCV2 have an immune-dysregulatory effect
Reduced macrophage and lymphocyte numbers
