Resp 3 Flashcards
BRDC
bovine respiratory disease complex
2 hit theory of BRDC
presumed that the animal is hit first with a viral infection which causes damage to the upper respiratory defences, allowing opportunistic infection of the upper and lower respiratory tract with normal resident respiratory bacteria
examples of viral infection BRDC
BRSV - bovine respiratory syncytial virus
PI-3 - parainfluenza virus -3
IBR - infectious bovine rhinotracheitis/bovineherpes virus 1
examples of bacterial infection BRDC
mannheima haemolytica - most common
Pasteurella multicoda
histophilus somni
mycoplasma bovis
BRDC is caused by
a mix of environmental factors, host factors, and pathogens
what is enzootic pneumonia of calves
due to combination of factors (environment, host, pathogens)
MULTIFACTORIAL
in enzootic pneumonia of calves, what kind of pneumonia do you see?
bronchopneumonia
BRSV infection impairs
the function of alveolar macrophages, which then allows for opportunistic secondary bacterial infections
which viral infection causes a biphasic clinical course in cattle?
BRSV
on histological examination, BRSV causes what kind of pneumonia
bronchointerstitial pneumonia (inflammation centered on airways AND the alveoli)
grossly, lungs look like bronchopneumonia (Cranioventral areas red colour due to atelectasis and rubbery texture)
what kind of pneumonia does mannheimia haemolytica cause
bronchopneumonia
mannheimia haemolytica gross lesions
classic cranioventral bronchopneumonia (often with abundant fibrin) (fibrinous bronchopneumonia)
on cut sections of lungs infected with mannheimia , you can often see
well-demarcated areas of coagulative necrosis
on histology, a characteristic feature of mannheimia pneumonia is the presence of
“oat cells” - mannheimia haemolytica produces a leukotoxin that causes neutrophils to lyse (fall apart), forming streams of nuclear material from the neutrophils that apparently looks similar to oats on histology
pasteurella multicoda is also a commensal bacteria of the nasopharynx, and requires ________________ to cause disease
some predisposing factor
gross lesions - pneumonic pausteurellosis
similar to classic shipping fever appearance of bronchopneumonia - cranioventral distribution of dark, red, firm, consolidated lung lobes
can you grossly distinguish between M. haemolytica, H. somni, and P. Multicoda?
no - need culture
all 3 commonly cause fibrinous bronchopneumonia
infection with Histophilus somni can cause several conditions, although
only one condition is usually present in any one animal
conditions histophilus somni can cause
bronchopneumonia and pleuritis are most important
pericarditis
polyarthritis
thromboembolic meningioencephalitis
mycoplasma bacteria lack a
cell wall
mycoplasmas have a variable growth rate, but most of the pathogenic mycoplasmas are
slow growing (often hard to culture, so send for PCR instead)
mycoplasma adhere to
ciliated epithelium of the respiratory tract
after adhering to the cilia, mycoplasma cause
cilliostasis - stops cilia from moving, so mucociliary apparatus stops working
mycoplasma bacteria are commonly
resistant to antibiotics :(
in cattle, the most important mycoplasma species in Canada is
mycoplasma bovis
mycoplasma bovis causes several disease syndromes
pneumonia
polyarthritis - 50% of cases
otitis media - unilateral or bilateral (droopy ears, circling/head tilts)
mastitis
mycoplasma pneumonia appearance
causes caseonecrotic bronchopneumonia with cranioventral consolidation, and multifocal raised white, sharply demarcated, friable white foci of caseous necrosis
- nodules in lungs are 2-10 mm
mycoplasma bovis causes particularly severe disease in
farmed bison
mycoplasma bacteria are gram positive but dont stain with gram stain due to their high lipid content - use what instead?
acid fast stain
the gross lesions of respiratory tuberculosis is the
tubercle - a nodular granuloma that is often mineralized
on histology, there are 3 characteristic features of a tubercle
central necrosis - often mineralized
small numbers of acid fast bacteria free within centre of within macrophages
rim of epithelial macrophages and multinucleated giant cells
3 big important mycobacterial diseases to be aware of in vet med?
tuberculosis (M. bovis or M. tuberculosis)
Johne’s disease (M. avium)
leprosy (M. lepraemurium and others)
tuberculosis causes what kind of pneumonia
granulomatous pneumonia
(includes disease caused by mycobacterium bovis and mycobacterium tuberculosis)
are both types of tuberculosis zoonotic?
yes! M. bovis is much lower zoonotic risk than M. tuberculosis
is mycobacteria bovis federally reportable?
YES to CFIA! Diagnosis of this disease would have trade implications and would initiate a CFIA disease outbreak investigation
acute bovine pulmonary emphysema and edema (aka fog fever) is caused by
3-methylindole toxicity
acute bovine pulmonary emphysema and edema classically occurs in
the fall, about 4-10 days after the animals are moved from dry to lush pastures
are young nursing ruminants affected by acute bovine pulmonary emphysema and edema?
no - they don’t yet have the rumen bacteria that convert L-tryptophan to 3-methylindole
Dictyocaulus viviparus (lungworm) causes which kind of pneumonia?
granulomatous
in general, the most common bacterial causes of pneumonia in small ruminants are
the same ones as discussed for cattle
parasitic pneumonia in small ruminants is caused by
Muellerius capillaris (nematode)
Ovine progressive pleuropneumonia (OPP) is also called
maedi visna virus (virus more common in sheep than goats)
gross pulmonary lesions of OPP or maedi visna virus are
heavy, pale lungs that fail collapse
caudal lobes most severely affected
rubbery texture on palpation
ovine pulmonary adenocarcinoma - also called
jaagsiekte sheep retrovirus
porcine respiratory disease complex - what is it
similar to shipping fever in feedlot cattle or enzootic pneumonia of dairy calves, involves pneumonia that develops as a result of complex web of environmental, host, and pathogen factors
porcine resp disease complex - is there a 2 hit theory
yaaaaa - 1st viral infection then bacterial
viral pathogens involved in porcine resp disease complex?
porcine reproductive and respiratory syndrome virus (PRRS)
postweaning multi systemic wasting syndrome (porcine circovirus 2)
swine influenza virus
most common bacteria in porcine resp disease complex?
mycoplasma hypneumoniae
actinobacillus pleuropneumoniae
pasteurella multicoda
porcine bronchopneumonia - actinobacillus pleuropneumonia (APP) - also known as
contagious pleuropneumonia
gross lesions of actinobacillus pleuropneumonia (APP)
distribution of this pneumonia is unique - often affecting the middle or caudal lung lobes and lesions can be unilateral or bilateral
gross respiratory lesions of PRRS virus?
lungs fail to collapse, there are rib impressions, and a firm texture on palpation, and there may be patchy discolouration
Swine have cell surface receptors for which influenza strains?
avian, human, and swine influenza strains
the gross necropsy lesions associated with swine influenza include:
cranioventral lobular distribution of atelectasis (bronchopneumonia)
often large oedematous lymph nodes
recurrent airway obstruction - RAO also known as
heaves or COPD (chronic obstructive pulmonary disease
RAO can cause _________ airway obstruction due to bronchospasm
reversible
is RAO similar to feline asthma
ya
RAO targets
small bronchioles and caudodorsal lung
rhodococcus equi causes ____________ pneumonia
bronchopneumonia
rhodococcus equi is a common cause of pneumonia in what age horse
1-6 month old foals
gross pulmonary lesion of rhodococcus equi is
pyogranulmatous bronchopneumonia, with 1-10cm diameter, tan, firm, raised coalescing nodules
do dogs have their own version of a resp disease complex.
YES - canine infectious respiratory disease complex, or CIRD, also known as kennel cough
common viral pathogens associated with CIRD include
canine parainfluenza virus
canine adenovirus type 2 (CAV-2)
canine herpes virus 1 (CHV-1)
common bacterial pathogens associated with CIRD
bordetella bronchiseptica
canine distemper virus - systems it affects
respiratory
GI
CNS
resp system gross lesions of distemper
in lung, patchy to diffuse, red to tan rubbery lesions below pleura at lung margins, and a diffuse, interstitial pneumonia
serous catarrhal or mucopurulent exudate of nasopharynx
dogs generally develop bacterial pneumonia when the
pulmonary defences have been impaired
bordetella bronchoseptica is an important component of the canine infectious respiratory disease complex and is commonly found with
mixed pathogen infections of upper respiratory tract of dogs
- bacteria adhere to cilia
big 4 systemic mycoses to remember are:
blastomyces dermatitidis
Coccidiodes immitus
Cryptococcus neoformans
Histoplasma capsulatum
are all 4 of the big 4 fungi capable of infecting humans + dogs & cats?
yes
big 4 fungi are dimorphic - means the organism exists as both yeast (in tissue) and hyphal/mold in environment forms. Which form is infectious>?
only the hyphal/mold form is infectious
is it safe to send big 4 fungi for culture?
NO!!! ZOONOTIC !!!
What is the most important common systemic mycotic disease of cats?
cryptococcus neoformans
histoplasmosis organisms found within
macrophages (intracellular)
clinical signs of heart worm infection are due to
pulmonary hypertension caused by vascular sclerosis (increased fibrosis in the walls of blood vessels) due to the presence of adult worms in the arteries
what is a common respiratory condition diagnosed in cats?
feline asthma
asthma is defined by the presence of
reversible airway obstruction (due to bronchoconstriction with inflammation similar to RAO in horses
just like dogs, cats can develop bacterial bronchopneumonia when pulmonary defences are
impaired
