Scour, Mycoplasma, Pinkeye, Orf, Trypanosomes

Question 1

What is the primary age range in calves for diarrhea caused by enterotoxigenic E. coli?

Answer 1

3-5 days

Question 2

Which virulence factors are specifically associated with enterotoxigenic E. coli causing neonatal diarrhea in calves?

Answer 2

STa and F5/F41

Question 3

What is the mechanism of action of the STa enterotoxin produced by enterotoxigenic E. coli?

Answer 3

Stimulation of intestinal ion and fluid secretion

Question 4

What are “attaching and effacing E. coli”?

a) A type of enterotoxigenic E. coli that produces STa

b) E. coli strains that adhere to the intestine, causing brush border dissolution

c) E. coli strains that primarily cause diarrhea in adult cattle

d) E. coli strains that are effectively treated with intestinal gels

Answer 4

E. coli strains that adhere to the intestine, causing brush border dissolution

Question 5

What is the primary source of infection for neonatal diarrhea in ruminants?

Answer 5

Feces of infected animals

Question 6

What is the main route of invasion for enteropathogens causing neonatal diarrhea?

Answer 6

Nasal and oropharyngeal mucosa

Question 7

How does colostrum provide protection against neonatal diarrhea?

Answer 7

By providing nonspecific bactericidal factors and specific antibodies (IgG and IgA)

Question 8

What is the significance of F5 (K99) and F41 fimbrial antigens in E. coli?

Answer 8

mediate adherence to intestinal mucosal cells

Question 9

What are the key clinical signs of neonatal diarrhea in ruminants?

a) Fever, constipation, and lethargy

b) Diarrhea, dehydration, and weakness

c) Vomiting, abdominal distension, and anorexia

d) Coughing, nasal discharge, and dyspnea

Answer 9

Diarrhea, dehydration, and weakness

Question 10

Why is milk feeding considered important in the treatment of neonatal diarrhea, despite potentially increasing fecal volume?

Answer 10

It meets the calf’s energy requirements and promotes gut healing

Question 11

What is the rationale for using NSAIDs in the treatment of neonatal diarrhea?

Answer 11

To reduce pain, inflammation, and fever, and to provide antisecretory effects

Question 12

What is the primary effect of intestinal gels and adsorbents like kaolin and pectin in treating neonatal diarrhea?

Answer 12

Increase in fecal consistency

Question 13

What is the mechanism of action of monoclonal F5 (K99) E. coli antibody administered orally to calves?

Answer 13

Passive immunization against a specific E. coli pathogen

Question 14

Which enteropathogens associated with neonatal diarrhea in ruminants pose a zoonotic risk?

Answer 14

Cryptosporidium parvum and Salmonella typhimurium

Question 15

What is the significance of “multifactorial” in the context of neonatal diarrhea?

Answer 15

That the disease is caused by multiple pathogens and environmental factors

Question 16

What is the primary role of fimbrial adhesins in enterotoxigenic E. coli pathogenesis?

Answer 16

Adherence to intestinal villi

Question 17

What is the consequence of severe infections with attaching and effacing E. coli?

Answer 17

Edema, mucosal erosions, and hemorrhage

Question 18

What are the three primary clinical manifestations associated with Mycoplasma bovis infection in cattle?

Answer 18

Mastitis, arthritis, and bovine respiratory disease (BRD)

Question 19

What unique structural characteristic of Mycoplasma spp. contributes to their resistance to penicillin and sensitivity to osmotic shock?

Answer 19

Lack of a cell wall

Question 20

What are the primary routes of transmission for Mycoplasma bovis in cattle?

Answer 20

Direct contact (nose-to-nose), aerosols, and contaminated milk/colostrum

Question 21

What is the significance of Variable Surface Lipoproteins (Vsps) in Mycoplasma bovis pathogenesis?

Answer 21

They mediate adherence to host cells and modulate the host immune response

Question 22

How does Mycoplasma bovis contribute to the development of chronic infections in cattle?

Answer 22

By modifying its vsp gene complex, altering the host immune response and promoting persistence

Question 23

What is the role of hydrogen peroxide in Mycoplasma bovis pathogenesis?

Answer 23

It damages host cells

Question 24

What is the significance of Mycoplasma bovis biofilm formation?

Answer 24

It contributes to persistence and resistance to environmental stressors and antimicrobials

Question 25

What are the common clinical signs of Mycoplasma bovis-induced pneumonia in cattle?

Answer 25

Mild to continuous cough, hyperpnea, dyspnea, and nasal discharge

Question 26

What is a hallmark clinical sign of Mycoplasma bovis-induced arthritis in calves?

Answer 26

Lameness with swelling of large rotator joints

Question 27

What is the characteristic lung lesion caused by Mycoplasma bovis?

Answer 27

Cranioventral consolidation with caseous or coagulative necrosis

Question 28

What is the "gold standard" method for detecting and identifying Mycoplasma bovis, and what are its limitations?

Answer 28

Microbial culture, time-consuming and requires specific conditions

Question 29

What is the primary reason for the increased observation of Mycoplasma bovis resistant isolates?

Answer 29

Overutilization of antimicrobials

Question 30

Which antibiotics have approved label indications for the treatment or control of Mycoplasma bovis pneumonia?

Answer 30

Tulathromycin, gamithromycin, and enrofloxacin

Question 31

What is the primary reason for tulathromycin's advantage over enrofloxacin in treating Mycoplasma bovis?

Answer 31

It has a longer duration of therapy (14 days vs. 4 days)

Question 32

What is a noted limitation of Mycoplasma bovis bacterin vaccines?

Answer 32

They often lead to more severe illness in vaccinated animals

Question 33

What diagnostic tool is heavily relied upon in the detection of Mycoplasma spp. due to their structural membrane proteins?

Answer 33

Serological tests such as indirect ELISA

Question 34

What is a key feature of Mycoplasma infections that makes diagnosis challenging? a) They are typically acute and easily resolved. b) They are usually chronic in nature. c) They always present with pathognomonic clinical signs. d) They readily respond to all antibiotic therapies.

Answer 34

They are usually chronic in nature.

Question 35

What is the defining characteristic of Stage 1 Infectious Keratoconjunctivitis (IKC) in cattle?

Answer 35

Blepharospasm, photophobia, conjunctivitis, and watery discharge

Question 36

What is the primary vector responsible for the transmission of Moraxella bovis in cattle?

Answer 36

Face flies (Musca autumnalis)

Question 37

What is the mechanism by which hemolytic strains of Moraxella bovis contribute to corneal ulceration?

Answer 37

Production of a pore-forming cytotoxin (hemolysin) leading to lysis of corneal epithelial cells

Question 38

What is the characteristic corneal change observed during Stage 2 of IBK?

Answer 38

Development of a small, grey cloudy area radiating across the cornea, with vascularization

Question 39

What is the significance of corneal neovascularization in IBK?

Answer 39

It results in a pink appearance of the cornea, hence the term "pinkeye"

Question 40

Which environmental factor is a significant risk factor for IBK due to its inflammatory effect on the cornea, particularly in animals lacking periocular pigmentation?

Answer 40

Ultraviolet solar irradiation

Question 41

What is the recommended antibiotic administration method for treating severe cases of IBK?

Answer 41

Subconjunctival injection or intramuscular/subcutaneous injection

Question 42

What is the purpose of using 1% atropine ointment in the treatment of IBK?

Answer 42

To alleviate pain associated with uveitis secondary to keratoconjunctivitis

Question 43

What is the primary benefit of using eye patches in the treatment of IBK?

Answer 43

To protect the affected eye from further irritation and reduce fly access

Question 44

What is the primary purpose of grass, weed, and brush control in preventing IBK?

Answer 44

To minimize pollen and mechanical irritation to the eyes

Question 45

What is the significance of eyelid pigmentation in preventing IBK?

Answer 45

It provides protection against ultraviolet light

Question 46

What is the recommended diagnostic approach for confirming Chlamydia and Mycoplasma spp. involvement in keratoconjunctivitis in sheep and goats?

Answer 46

Cytologic evaluation of stained conjunctival scrapings and PCR

Question 47

What is the significance of using fluorescein dye in diagnosing IBK?

Answer 47

It stains corneal ulcers, revealing the extent of corneal damage

Question 48

What is the most common reason for relapse in IBK cases?

Answer 48

Persistent environmental risk factors

Question 49

Which species is more likely to require special media for microbial culture during the diagnosis of keratoconjunctivitis? a) Moraxella bovis b) Chlamydia and Mycoplasma spp. c) Listeria monocytogenes d) Moraxella ovis

Answer 49

Chlamydia and Mycoplasma spp.

Question 50

What is the primary reason for avoiding overhead hay feeders in preventing IBK?

Answer 50

To minimize mechanical irritation from hay chaff and mature seed heads

Question 51

What is a key limitation of commercial and autogenous pinkeye vaccines? a) They are highly expensive b) They require frequent boosters c) Reported results from producers and veterinarians have been mixed d) They are only effective against Moraxella bovis strains

Answer 51

Reported results from producers and veterinarians have been mixed

Question 52

What are the primary economic impacts of African Animal Trypanosomiasis on livestock?

Answer 52

Anemia, loss of condition, and reproductive issues

Question 53

Which three Trypanosoma species are the most significant causative agents of African Animal Trypanosomiasis transmitted by tsetse flies?

Answer 53

T. congolense, T. vivax, T. brucei subsp. brucei

Question 54

What is the biological vector responsible for transmitting the trypanosomes that cause African Animal Trypanosomiasis?

Answer 54

Tsetse flies (Glossina spp.)

Question 55

Which Trypanosoma species is particularly associated with mechanical transmission by biting flies and surgical instruments?

Answer 55

T. vivax

Question 56

What is the initial site of trypanosome inoculation in the host animal, and what local lesion is formed?

Answer 56

Skin, causing a localized inflammation (chancre)

Question 57

How do Trypanosoma species evade the host's immune response?

Answer 57

By switching variable surface-coat glycoproteins (antigenic variation)

Question 58

What are the primary clinical signs of chronic African Animal Trypanosomiasis in ruminants? a) Hyperthermia, polyuria, and polydipsia b) Intermittent fever, anemia, lymphadenopathy, and weight loss c) Neurological signs, seizures, and paralysis d) Dermatitis, alopecia, and pruritus

Answer 58

Intermittent fever, anemia, lymphadenopathy, and weight los

Question 59

What is the characteristic hemorrhagic syndrome observed in cattle infected with some isolates of T. vivax?

Answer 59

Widespread visceral and mucosal hemorrhages, particularly in the gastrointestinal tract

Question 60

What is the most sensitive rapid diagnostic method for detecting trypanosomes in infected animals?

Answer 60

Examination of a wet mount of the buffy coat after centrifugation

Question 61

What is the primary mechanism of action of diminazene aceturate and isometamidium chloride used in treating African Animal Trypanosomiasis?

Answer 61

Disruption of parasite cell membrane integrity

Question 62

What are the primary clinical features of Orf (Contagious Ecthyma) caused by ORFV infection?

Answer 62

Vesicles, pustules, and scabs, particularly around the mouth

Question 63

What is the typical morbidity rate of Orf in yearling sheep and goats?

Answer 63

Up to 100%

Question 64

How is ORFV primarily transmitted in sheep and goats?

Answer 64

Direct contact or indirectly from the environment or fomites

Question 65

What are the common portals of entry for ORFV in sheep and goats?

Answer 65

Abrasions in the skin or mucosa

Question 66

What is the primary lesion development timeline after ORFV infection?

Answer 66

Macules, papules, transient vesicles, pustules, and scabs

Question 67

What are the common complications associated with Orf in sheep and goats?

Answer 67

Secondary myiasis, bacterial mastitis, and lameness

Question 68

What are the characteristic histological lesions associated with ORFV infection?

Answer 68

Ballooning degeneration and swelling of keratinocytes, with intraepidermal micro-abscesses

Question 69

What is the diagnostic method considered most convenient, practical, and cost-effective for confirming Orf?

Answer 69

PCR

Question 70

What is the significance of "auto-vaccination" in the context of Orf?

Answer 70

It involves intentional exposure of healthy animals to scabs from infected animals

Question 71

What is the primary risk group for zoonotic transmission of ORFV?

Answer 71

Farmers, herders, slaughterers, and veterinarians who handle infected animals

Question 72

Which Trypanosoma species is known to have the shortest development cycle within the tsetse fly?

Answer 72

T. vivax

Question 73

What is the role of Tabanidae (horseflies) and stable flies (Stomoxys spp.) in the transmission of African Animal Trypanosomiasis?

Answer 73

They act as mechanical vectors, especially for T. vivax.

Question 74

What is the primary reason for the absence of a protective vaccine against African Animal Trypanosomiasis?

Answer 74

The ability of trypanosomes to undergo antigenic variation.

Question 75

What is the primary reason for the seasonal occurrence of Orf outbreaks, particularly around lambing?

Answer 75

Stress and reduced immunity in animals during lambing, coupled with environmental factors.

Question 76

What is the primary method for preventing the spread of African Animal Trypanosomiasis in disease-free areas following the introduction of infected animals?

Answer 76

Stamping out (quarantines, movement controls, and euthanasia) combined with vector control.

Question 77

What is the most significant factor contributing to the high morbidity rate of Orf in young sheep and goats?

Answer 77

High titers of stable virus in scabs, leading to easy transmission among susceptible animals.