Lecture 33 11/26/24 Flashcards
Which part of the lungs is infected in pneumonia?
alveoli
What are the characteristics of bronchopneumonia?
-tends to be cranioventral
-aerogenous spread
-firm, consolidated lungs
-caused by bacteria and mycoplasmas
-can occur with aspiration pneumonia
-inflammation in conducting airways
What are the characteristics of interstitial pneumonia?
-tends to be more diffuse
-aerogenous or hematogenous spread
What is the main characteristic of embolic/hematogenous pneumonia?
has a multifocal, random spread
What are the characteristics of Mannheimia haemolytica?
-most important cause of bacterial pneumonia in cattle
-sheep and goats similarly affected
-causes severe necrosis, tons of fibrin, and neutrophilic inflammation
-causes geographic areas of necrosis
-big part of shipping fever/BRDC
What is the pathophysiology behind M. haemolytica being so bad?
-produces a leukotoxin that kills neutrophils
-releases more damaging substances from dead neutrophils
-bystander tissue destruction
-more neutrophils die
-cycle continues
What is the classic histologic feature of M. haemolytica?
oat cells
What are the characteristics of Histophilus somni?
-causes a fibrinosuppurative bronchopneumonia
-may cause septicemia
What are the characteristics of bronchopneumonia caused by Mycoplasma bovis in cattle?
-cranioventral consolidation
-suppurative bronchopneumonia +/- bronchiectasis
-can be caseous with necrosis and inflammation
What are the characteristics of pneumonic pasteurellosis?
-affects cattle, pigs, and rabbits
-part of enzootic pneumonia in calves
-causes snuffles in rabbits
-causes bronchopneumonia +/- abscession +/- pleuritis
-often follows viral infection in pigs and cattle
-caused by P. multocida
What are the characteristics of porcine pleuropneumonia?
-causes fibrin, necrosis, and hemorrhage
-starts off caudodorsal
-often spreads diffusely
What is the pathophysiology of Actinobacillus pleuropneumoniae?
-bacterial leukotoxin causes extensive neutrophil death
-neutrophil death leads to secondary damage and necrosis
-lungs become firm, red, and coated with fibrin
What are the characteristics of Mycoplasma hyopneumoniae in pigs?
-causes enzootic pneumonia
-causes “fish flesh” lungs
-often complicated by secondary bacterial pathogens
What causes enzootic pneumonia in sheep?
Mycoplasma ovipneumoniae
What causes bronchopneumonia in dogs?
-B. bronchiseptica
-Strep. spp.
What causes bronchopneumonia in cats?
-P. multocida
-Strep. spp.
-B. bronchiseptica
What causes bronchopneumonia in horses?
Strep. equi equi
What are the characteristics of aspiration pneumonia?
-secondary to inhaled foreign material
-typically cranioventral
-often necrotizing
What are the risk factors for aspiration pneumonia?
-anesthesia
-balling gun/tube feeding
-megaesophagus
-cleft palate
-dysphagia/nerve damage
What are the sequela of purulent bronchopneumonia?
-bronchiectasis
-pulmonary abscesses
-pleural adhesions
-atelectasis
-emphysema
What happens to the lungs during interstitial pneumonia?
-lungs become thick and “meaty”
-fail to collapse
-may see rib impressions
-often feel rubbery
-sections still usually float
What are the potential causes of interstitial pneumonia?
-viral**
-allergic
-toxic
-parasitic
What are the histology changes associated with interstitial pneumonia?
-type II pneumocyte hyperplasia
-hyaline membranes
-lymphocytes and plasma cells in septa
What are the characteristics of bronchointerstitial pneumonia?
-combo of interstitial and bronchial inflammation
-seen with primary viral infections followed by secondary bacterial infections
What are the characteristics of shipping fever?
-usually multifactorial
-both interstitial pneumonia and bronchopneumonia
-interstitial pneumonia occurs due to bovine herpesvirus-1, bovine parainfluenza virus-3, or BRSV
What are the characteristics of bovine respiratory syncytial virus/BRSV?
-important in young calves and feedlot cattle
-predisposed by crowding, stress, transportation, and poor air quality
-begins cranioventral
-bronchointerstitial to interstitial pneumonia on histo.
Which bacterial infections can complicate BRSV?
-M. haemolytica
-P. multocida
-Trueperella pyogenes
What is a potential sequela of BRSV?
hypersensitivity reaction if reinfected
What are the characteristics of parainfluenza virus-3?
-lots of overlap with BRSV
-same risk factors and susceptibility to bact. infections
-less severe
What are the characteristics of bovine pulmonary edema and emphysema?
-atypical interstitial pneumonia/fog fever
-damage to type I pneumocytes and bronchial epithelium causes edema and emphysema
Which toxins cause fog fever?
-lush sweet clover
-moldy sweet potatoes
-perilla mint
What are hyaline membranes?
hallmark feature of fog fever that results from severe damage to the interstitium
What are the non-toxic causes of hyaline membranes?
-BRSV
-Dictyocaulus viviparus
-type III hypersensitivity
What are the characteristics of equine viral rhinopneumonitis?
-caused by equine herpesvirus 1 and 4
-young horses most affected
-causes bronchointerstitial pneumonia
What are the characteristics of equine influenza?
-H3N8
-very contagious
-causes bronchointerstitial pneumonia
-reportable in some states
How do herpesvirus and influenza affect the lungs?
-self-limiting on their own
-predispose to secondary bacteria infections
-predispose to ARDS
What are the characteristics of maedi visna?
-aka ovine progressive pneumonia
-caused by small ruminant lentivirus; type of retrovirus
-causes interstitial pneumonia with lymphocytes and plasma cells
What are the characteristics of caprine arthritis and encephalitis virus?
-caused by small ruminant lentivirus; retrovirus
-transmitted in milk
-lungs fail to collapse; rib impressions common
-alveoli fill up with surfactant
What are the characteristics of pestis de petits ruminants?
-morbillivirus
-lesions similar to distemper
-causes bronchointerstitial pneumonia
-foreign animal disease
What are the characteristics of canine distemper virus?
-causes bronchointerstitial pneumonia
-predisposes to secondary infections
-often causes mucopurulent conjunctivitis and rhinitis
-attacks the epithelium
What are the characteristics of canine influenza?
-typically mildly disease in the lungs
-can cause necrosis of bronchioles and pleural and subpleural hemorrhages
What are the characteristics of canine adenovirus-2?
-usually subclinical
-can cause disease in immunocompromised individuals
-necrotizing bronchiolitis
-large magenta intranuclear inclusion bodies
What are the characteristics of feline herpesvirus-1?
-causes URT disease
-potential for lymphoplasmacytic to fibrinonecrotic interstitial pneumonia
-not usually fatal on its own
What are the characteristics of feline calicivirus?
-type II pneumocyte hyperplasia
-type I pneumocyte necrosis
-lymphoplasmacytic to necrotizing inflammation
-virulent strains cause systemic disease
What are the characteristics of PRRS?
-range of disease and virulence
-can cause interstitial pneumonia and hypoxia
-infects macrophages and spares conducting cells
-can cause secondary bacterial infections and septicemia
What are the characteristics of porcine circovirus-2?
-interstitial pneumonia
-macrophages play bigger role
What are the characteristics of pseudorabies?
-starts as a rhinitis that progresses to pneumonia
-eosinophilic intranuclear inclusion bodies on histo
-inhibits alveolar macrophages and leads to secondary bact. infections
What are the characteristics of swine influenza?
-more necrosis than PRRS or PCV-2
-more commonly a bronchointerstitial pneumonia
-checkerboard pattern on the lungs
-predisposes to secondary bact. infections
