Respiratory 3 Flashcards
you are talking to a bovine feelot producer and he tells you he thinks some of his new cows that just arrived have shipping fever. What do you tell him the real name of this disease is?
bovine respiratory disease complex
the bovine feedlot producer wants to know what causes bovine respiratory disease complex. what do you tell him?
it is a multifactorial disease caused by a mix of environmental factors, host factors, and pathogen factors
the bovine feedlot producer doesn’t like your explanation (what a jerk) of bovine respiratory disease complex and wants more specifics. He says “aren’t there viruses or bacteria involved?” You then say “yes, the most commonly involved viruses are _______ and the most common bacteria involved are ______
bovine respiratory syncytial virus, parainfluenza 3 virus, infectious bonvine rhinotrachetitis (bovine herpes virus 1)
manheimia haemlytica, pasturella multocida, histophilus somni, mycoplasma bovis
you go visit a dairy farm to go see a bunch of calves kept indoors. They have their necks extended, there is foaming at the mouth, and they are all standing with a wide stance. What do these dairy cows have?
enzootic pneumonia of calves caused by a combination of envionrmental, host, and pathogen factors (similar to those with shipping fever)
you explain to the dairy producer that there is a 2 hit theory when it comes to his calves with enxootic penumonia. what is the 2 hit theory and what other disease is associated with the two hit theory?
the 2 hit theory suggest that first the animal is hit with a viral infection, and the second hit is an OPPORTUNISTIC bacterial infection. another disease associated with this is shipping fever or bovine respiratory disease complex
you get a necopsy of a calf on path rotations and you were told that the calf experienced transient pyrexia and mild respiratory disease and then temporarily inmproved. The calf then experienced a severe rapid onset of respiratory distress and died shortly after. When you open up the lungs to look, it looks like bronchopneumonia: the craniocaudal lung lobes are dark red and meaty, and the caudo-dorsal lung is voluminous and puffy. when you look at the histology slides you see that the alevolar epithelial cells have formed large multinucelated syncytial cells. What did this calf die from, and explain the pathogenesis
bovine respiratory syncytial virus:
the virus impairs alevolar macrophages which allows for opportunisitc bacterial infections.
bovine respiratory synsyctial virus technically causes what kind of penumonia?
bronchointerstisial pneumonia with inflammation centered on airways and the alveoli
I’m a commensalistic bacteria normally found in the nasopharynx in cattle and I cause fibrinous bronchopneumonia. I am a part of the bovine respiratory disease complex. What am I? What do you expect the lungs to look like in which I invade?
mannheimia haemolytica
classic cranioventral bronchopneumonia, well demarcated areas of caogulative necrosis
what are “oat cells” and what bacterial disease are they indicitave of?
mannheimia maemolytica: production of a leukotoxin causes lysis of neutrophils forming streams of neclear material fromthe dead neutrophils and this looks like oats on histo
there are 3 bacteria that look similar upon presentation on lung necropsy. what are these 3 bacteria and how do they present? How do you differentiate them?
Mannheimia haemolytica, histophilus somni, and pasturella multocida. All present as fibrinous bronchopneumonoa or fibrinous pleuritis. CULTURE
respiratory infection of histophilus somni causes 4 conditions. what are they? can all 4 of these happen at the same time?
bronchopneumonia and pleuritis
pericarditis
polyarthritis (septic joints)
thromboembolic meningoencephalitis
usually or 1 or 2 of these happen, never all 4 at once
mycoplasma bacteria species show high levels of antibiotic resistance.why?
they lack cell walls which means certain types of antibiotics don’t work on them
You are talking to a fellow vet student working on a necropsy of a cow that you both think is infected with a mycoplasma bacteria. The student suggests that the lung samples be cultured to find out. Is this the right move? Why or why not?
NO this is NOT the right move! Mycoplasms are slow groing and therefore difficult to culture so PCR is a better diagnostic!
how do mycoplasma bacteria spp cause disease?
mycoplasma adhere to the ciliated epithelium of the respiratory tract and cause ciliostasis which impais the mucociliary clearance
what is the most important mycoplasma species in all of canada?
mycoplasma bovis
what 3 syndromes are caused by mycoplasma bovis?
penumonia, polyarthritis, otitis media
you are doing a necropsy and you find caseonecrotic bronchopneumonia with cranioventral consolidation with multifocal, raised, white, sharply demarcated, friable foci of caneous necrosis. what is your number 1 differential? if you were to do histology, what would you likely see?
mycoplasma bovis
histology: bronchietasis
what is that DARN BACTERIA that kills THEM BISON?
mycoplasma bovis
if you suscpect mycobacteria are responsible for a penumonia case you just saw, what will you tell the histology people to do?
use acid fast stain because the bacteria don’t stain with a gram stain because of their high lipid content (even though they are gram positive)