Lecture 33 11/26/24

Question 1

Which part of the lungs is infected in pneumonia?

Answer 1

alveoli

Question 2

What are the characteristics of bronchopneumonia?

Answer 2

-tends to be cranioventral
-aerogenous spread
-firm, consolidated lungs
-caused by bacteria and mycoplasmas
-can occur with aspiration pneumonia
-inflammation in conducting airways

Question 3

What are the characteristics of interstitial pneumonia?

Answer 3

-tends to be more diffuse
-aerogenous or hematogenous spread

Question 4

What is the main characteristic of embolic/hematogenous pneumonia?

Answer 4

has a multifocal, random spread

Question 5

What are the characteristics of Mannheimia haemolytica?

Answer 5

-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

Question 6

What is the pathophysiology behind M. haemolytica being so bad?

Answer 6

-produces a leukotoxin that kills neutrophils
-releases more damaging substances from dead neutrophils
-bystander tissue destruction
-more neutrophils die
-cycle continues

Question 7

What is the classic histologic feature of M. haemolytica?

Answer 7

oat cells

Question 8

What are the characteristics of Histophilus somni?

Answer 8

-causes a fibrinosuppurative bronchopneumonia
-may cause septicemia

Question 9

What are the characteristics of bronchopneumonia caused by Mycoplasma bovis in cattle?

Answer 9

-cranioventral consolidation
-suppurative bronchopneumonia +/- bronchiectasis
-can be caseous with necrosis and inflammation

Question 10

What are the characteristics of pneumonic pasteurellosis?

Answer 10

-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

Question 11

What are the characteristics of porcine pleuropneumonia?

Answer 11

-causes fibrin, necrosis, and hemorrhage
-starts off caudodorsal
-often spreads diffusely

Question 12

What is the pathophysiology of Actinobacillus pleuropneumoniae?

Answer 12

-bacterial leukotoxin causes extensive neutrophil death
-neutrophil death leads to secondary damage and necrosis
-lungs become firm, red, and coated with fibrin

Question 13

What are the characteristics of Mycoplasma hyopneumoniae in pigs?

Answer 13

-causes enzootic pneumonia
-causes “fish flesh” lungs
-often complicated by secondary bacterial pathogens

Question 14

What causes enzootic pneumonia in sheep?

Answer 14

Mycoplasma ovipneumoniae

Question 15

What causes bronchopneumonia in dogs?

Answer 15

-B. bronchiseptica
-Strep. spp.

Question 16

What causes bronchopneumonia in cats?

Answer 16

-P. multocida
-Strep. spp.
-B. bronchiseptica

Question 17

What causes bronchopneumonia in horses?

Answer 17

Strep. equi equi

Question 18

What are the characteristics of aspiration pneumonia?

Answer 18

-secondary to inhaled foreign material
-typically cranioventral
-often necrotizing

Question 19

What are the risk factors for aspiration pneumonia?

Answer 19

-anesthesia
-balling gun/tube feeding
-megaesophagus
-cleft palate
-dysphagia/nerve damage

Question 20

What are the sequela of purulent bronchopneumonia?

Answer 20

-bronchiectasis
-pulmonary abscesses
-pleural adhesions
-atelectasis
-emphysema

Question 21

What happens to the lungs during interstitial pneumonia?

Answer 21

-lungs become thick and “meaty”
-fail to collapse
-may see rib impressions
-often feel rubbery
-sections still usually float

Question 22

What are the potential causes of interstitial pneumonia?

Answer 22

-viral**
-allergic
-toxic
-parasitic

Question 23

What are the histology changes associated with interstitial pneumonia?

Answer 23

-type II pneumocyte hyperplasia
-hyaline membranes
-lymphocytes and plasma cells in septa

Question 24

What are the characteristics of bronchointerstitial pneumonia?

Answer 24

-combo of interstitial and bronchial inflammation
-seen with primary viral infections followed by secondary bacterial infections

Question 25

What are the characteristics of shipping fever?

Answer 25

-usually multifactorial -both interstitial pneumonia and bronchopneumonia -interstitial pneumonia occurs due to bovine herpesvirus-1, bovine parainfluenza virus-3, or BRSV

Question 26

What are the characteristics of bovine respiratory syncytial virus/BRSV?

Answer 26

-important in young calves and feedlot cattle -predisposed by crowding, stress, transportation, and poor air quality -begins cranioventral -bronchointerstitial to interstitial pneumonia on histo.

Question 27

Which bacterial infections can complicate BRSV?

Answer 27

-M. haemolytica -P. multocida -Trueperella pyogenes

Question 28

What is a potential sequela of BRSV?

Answer 28

hypersensitivity reaction if reinfected

Question 29

What are the characteristics of parainfluenza virus-3?

Answer 29

-lots of overlap with BRSV -same risk factors and susceptibility to bact. infections -less severe

Question 30

What are the characteristics of bovine pulmonary edema and emphysema?

Answer 30

-atypical interstitial pneumonia/fog fever -damage to type I pneumocytes and bronchial epithelium causes edema and emphysema

Question 31

Which toxins cause fog fever?

Answer 31

-lush sweet clover -moldy sweet potatoes -perilla mint

Question 32

What are hyaline membranes?

Answer 32

hallmark feature of fog fever that results from severe damage to the interstitium

Question 33

What are the non-toxic causes of hyaline membranes?

Answer 33

-BRSV -Dictyocaulus viviparus -type III hypersensitivity

Question 34

What are the characteristics of equine viral rhinopneumonitis?

Answer 34

-caused by equine herpesvirus 1 and 4 -young horses most affected -causes bronchointerstitial pneumonia

Question 35

What are the characteristics of equine influenza?

Answer 35

-H3N8 -very contagious -causes bronchointerstitial pneumonia -reportable in some states

Question 36

How do herpesvirus and influenza affect the lungs?

Answer 36

-self-limiting on their own -predispose to secondary bacteria infections -predispose to ARDS

Question 37

What are the characteristics of maedi visna?

Answer 37

-aka ovine progressive pneumonia -caused by small ruminant lentivirus; type of retrovirus -causes interstitial pneumonia with lymphocytes and plasma cells

Question 38

What are the characteristics of caprine arthritis and encephalitis virus?

Answer 38

-caused by small ruminant lentivirus; retrovirus -transmitted in milk -lungs fail to collapse; rib impressions common -alveoli fill up with surfactant

Question 39

What are the characteristics of pestis de petits ruminants?

Answer 39

-morbillivirus -lesions similar to distemper -causes bronchointerstitial pneumonia -foreign animal disease

Question 40

What are the characteristics of canine distemper virus?

Answer 40

-causes bronchointerstitial pneumonia -predisposes to secondary infections -often causes mucopurulent conjunctivitis and rhinitis -attacks the epithelium

Question 41

What are the characteristics of canine influenza?

Answer 41

-typically mildly disease in the lungs -can cause necrosis of bronchioles and pleural and subpleural hemorrhages

Question 42

What are the characteristics of canine adenovirus-2?

Answer 42

-usually subclinical -can cause disease in immunocompromised individuals -necrotizing bronchiolitis -large magenta intranuclear inclusion bodies

Question 43

What are the characteristics of feline herpesvirus-1?

Answer 43

-causes URT disease -potential for lymphoplasmacytic to fibrinonecrotic interstitial pneumonia -not usually fatal on its own

Question 44

What are the characteristics of feline calicivirus?

Answer 44

-type II pneumocyte hyperplasia -type I pneumocyte necrosis -lymphoplasmacytic to necrotizing inflammation -virulent strains cause systemic disease

Question 45

What are the characteristics of PRRS?

Answer 45

-range of disease and virulence -can cause interstitial pneumonia and hypoxia -infects macrophages and spares conducting cells -can cause secondary bacterial infections and septicemia

Question 46

What are the characteristics of porcine circovirus-2?

Answer 46

-interstitial pneumonia -macrophages play bigger role

Question 47

What are the characteristics of pseudorabies?

Answer 47

-starts as a rhinitis that progresses to pneumonia -eosinophilic intranuclear inclusion bodies on histo -inhibits alveolar macrophages and leads to secondary bact. infections

Question 48

What are the characteristics of swine influenza?

Answer 48

-more necrosis than PRRS or PCV-2 -more commonly a bronchointerstitial pneumonia -checkerboard pattern on the lungs -predisposes to secondary bact. infections