Respiratory Diseases

Question 1

In ruminants significant pulmonary dz can be present without _____________

Answer 1

Auscultate abnormality

Question 2

Bovine Respiratory Dz Complex

Answer 2

Lower resp. dz of cattle: bronchopneumonia, interstitial pneumonia, metastatic pneumonia

Question 3

Bronchopneumonia

Answer 3

Invasion of pathogens through bronchi to the lungs
Signs: sepsis, effusion, abnormal lung sounds (crackles, wheezes) and consolidation

Question 4

Bacterial agents of BRDC

Answer 4

Normal inhabitants of bovine nasopharynx:
Manheimia haemolytica , pasteurella multocida, histophilus somni, mycoplasma bovis

Question 5

Mannheimia (Pasteurella) haemolytica

Answer 5

Gram- aerobic
A1 most common serotype (pathogenic)
Most common bacteria in feedlot cattle with pneumonia

Question 6

Pasteurella multocida

Answer 6

Gram- aerobic
Serotype A most commonly found in BRDC

Question 7

Histophilus somni

Answer 7

Gram- aerobic
Found on genital + resp. mucosa
Causes a variety of dz + resp (TEME)

Question 8

Mycoplasma bovis

Answer 8

Mycoplasmas bound by a single membrane and lack a cell wall
Causes multiple dz (arthritis + tenosynovitis)

Question 9

Viral agents of BRDC

Answer 9

Infectious bovine rhinotracheitis virus (Herpes)- DNA
Bov Resp. Syncytial virus- RNA
Bov Parainfluenza virus- RNA
Bov viral diarrhea virus- RNA, immunosuppressive
Bov Resp. coronavirus- RNA

Question 10

How is Bov. respiratory syncytial virus related to humans?

Answer 10

Related to human resp. syncytial virus and an important cause of resp. dz in young children and elderly

Question 11

How is Bov. parainfluenza virus related to humans?

Answer 11

Related to human PI-3 and used as intranasal MLV in infants

Question 12

BRDC distribution

Answer 12

Younger immunodeficient calves (enzootic calf pneumonia) or in adult stress cattle (shipping fever)

Question 13

BRDC transmission

Answer 13

Bacteria: aerosol, dust
Viruses: aerosol, direct contact and fomites

Question 14

What factors influence BRDC?

Answer 14

Interaction of agents (bacteria, viruses), hosts (susceptible hosts), environment (cold, wet, dusty, windy)

Question 15

Common CS of BRDC?

Answer 15

Fever, depression, anorexia, nasal discharge, tachypnea, pleuritis, crackles, wheezes over cranioventral lung lobes

Question 16

Other CS that histophilus somni causes with BRDC

Answer 16

Joint effusion/ infertility or abortion/ otitis/ conjunctivitis/ neuro signs

Question 17

Other CS that mycoplasma bovis causes of BRDC

Answer 17

Joint effusion/ colitis or conjunctivitis

Question 18

Pathology of BRDC (viruses)

Answer 18

Infects epithelial cells and ciliated epithelium in upper resp. and bronchi →destruction of cells →↓ mucocillary clearance and ↑ susceptibility to secondary infection
Immunosuppression →↓ neutro chemotaxis and ↓ lympho blastogenesis and expression of MHC

Question 19

Pathogenesis of mannheimia (BRDC)

Answer 19

Exotoxin (leukotoxin → cytolysis of neutros)
Endotoxin → inflamm by initiating complement cascade activiating neutros and macros to produce cytokines
Leukopenia

Question 20

Pathogenesis of other bacteria (BRDC)

Answer 20

Pasteurella: endotoxin
Histophilus: lipooligosaccharide → endotoxemia
Mycoplasma: CM expressed surface proteins (Vsps)

Question 21

Pathogenesis of infectious bov rhinotracheitis

Answer 21

Latent infection in neural tissue

Question 22

Lesions of BRDC

Answer 22

Cranioventral lung consolidation
Fibrinopurulent exudate in resp. passages

Question 23

Dx for BRDC (bacteria)

Answer 23

CS
Bacteria: cx from trans-tracheal aspirate or resp. tissues @ necropsy

Question 24

Dx for BRDC (virus)

Answer 24

CS
Nasal swabs or resp. tissues @ necropsy for virus isolation or immunofluorescent assays or PCR

Question 25

Tx for BRDC

Answer 25

Abx (amoxicillin, ceftiofur, enrofloxacin, etc- rotate between abx) Anti-inflamms: flunixin meglumine

Question 26

Prevention and control for BRDC

Answer 26

Reduced exposure to dust, wind, cold and reduced crowding Vaccines: inactivated/ killed**, attenuated/ modified live

Question 27

Tuberculosis

Answer 27

Consumption, scrofula, TB Debilitating dz, formation of nodular granulomas (tubercles) Zoonotic and reportable

Question 28

Casual agent of tuberculosis

Answer 28

M. Bovis (domestic animals) M. Tuberculosis, M. Avium Acid-fast bacilli

Question 29

Mode of transmission for tuberculosis

Answer 29

Resp route via aerosol droplets Ingestion (horses) In feces, urine, semen and milk

Question 30

Which animals are more susceptible to tuberculosis

Answer 30

Cattle and goats Sheep resistant Horses

Question 31

Factors influencing tuberculosis

Answer 31

Housing, crowded conditions Main reservoirs: cattle and man

Question 32

Pathogenesis of tuberculosis

Answer 32

TB bacilli stimulate formation of granulomas in lungs Form primary complexes: focal necrotic area surrounded by granuloma containing mononuclear cells and disseminate to other organs

Question 33

Lesions associated with tuberculosis

Answer 33

Thick encapsulated granulomas with pus Granulomas in LNs, lungs and liver

Question 34

Dx of tuberculosis

Answer 34

Screening test: Intradermal tuberculin test in cd. tail fold Confirmatory test: comparative cervical test in side of neck

Question 35

Tx for tuberculosis

Answer 35

Cull infected animals due to risk of transmission to animals Rifampin and isoniazid in horses