Coronaviridae

Question 1

What are the viruses in Group 1a?

Answer 1

Feline infectious peritonitis/feline enteric coronavirus, canine coronavirus, transmissible gastroenteritis virus of swine, porcine respiratory coronavirus

Question 2

What is the virus in group 1b?

Answer 2

Porcine epidemic diarrhea virus

Question 3

What are the viruses in group 2a?

Answer 3

Porcine hemagglutinizing encephalomyelitis virus, mouse hepatitis virus, sialodacryoadentiis virus of rats (wtf), and bovine coronavirus

Question 4

What viruses are in group 2b?

Answer 4

SARS in humans and cats, bats,

Question 5

What viruses are in group 3?

Answer 5

Avian infectious bronchitis virus, turkey coronavirus, bluecomb virus

Question 6

Describe the structure and genome of coronaviruses

Answer 6

Enveloped with large club-shaped spikes
Icosahedral internal core structure enclosing a helical nucleocapsid (coronavirus) OR tightly coiled tubular nucleocapsid bent into doughnut shapes (Torovirus)
Linear ssRNA

Question 7

Where do coronaviruses replicate?

Answer 7

Cytoplasm, virions are formed by budding/exocytosis

Question 8

Which class does transmissible gastroenteritis in pigs (TGE) belong?

Answer 8

1a

Question 9

Under which OIE class does TGE belong?

Answer 9

List B

Question 10

What are the two forms of TGE?

Answer 10

Epidemic: first introduced into a susceptible herd, observed most often in winter, high morbidity and mortality in piglets
Endemic: persists in partially immune herd or due to a concurrent PRCV infection, less severe and lower mortality/morbididy

Question 11

Transmission of TGE?

Answer 11

Major route is fecal-oral but can also be spread by aerosol, contaminated objects, suckling milk from infected pigs

Question 12

Describe the pathogenesis of TGE

Answer 12

Infects villi, causing villus atrophy and resulting in malabsorption. Then diarrhea

Question 13

Clinical signs of TGE?

Answer 13

Profuse diarrhea, vomiting, severe depression and dehydration, feces containing clots of undigested milk, watery, yellow green stool with offensive odor, distended intestine, dilated stomach, gases and atrophy of intestinal vili, bloated gut

Question 14

Diagnosis of TGE?

Answer 14

Necropsy, histopathology, antigen detection by FA, IHC, detection of nucleic acid by RT-PCR

Question 15

What group does porcine epidemic diarrhea (PED) belong to?

Route of transmission?

Answer 15

Group 1a; although clinical signs similar to TGE, unrelated!
Spreads via oral-fecal route and has nearly 100% morbidity but variable mortality in young pigs

Question 16

What group does porcine hemagglutinating encephalomyelitis (vomiting and wasting disease) belong to?

Answer 16

2a

Question 17

Describe the vomiting and wasting disease pathogenesis:

Answer 17

Aerosol route/nasal secretion contact from infected carrier–> virus replicates in nasal mucosa and then lungs, tonsils, small intestine–> spreads to CNS from PNS–> replication in brain stem, cerebrum, cerebellum THEN EITHER CAUSES ACUTE ENCEPHALOMYELITIS (piglets disturbs gastric emptying, causes vomiting and malnutrition and leads to wasting (usually piglets

Question 18

Clinical findings of the wasting and vomiting disease form?

Answer 18

Repeated retching and vomiting, anorexia, constipation, rapid emaciation, dehydration, cyanosis, comatose and death

Question 19

Encephalomyelitic form clinical findings?

Answer 19

Muscle tremors, hyperesthesis, blindness, nystagmus, conuvulsions, death

Question 20

What group does bovine coronavirus infection in calves belong in?

Answer 20

2a

Question 21

Describe the pathogenesis of bovine coronavirus in calves?

Answer 21

Fecal-oral or maybeee aerosol transmission, primary replication in small intestine (also in upper resp. tract causing minor respiratory symptoms), resulting in atrophy of villi, destruction of crypt epithelium.
Malabsorption, increased secretory function–> profuse diarrhea
Need fluid therapy***

Question 22

Describe the transmission, clinical signs, and pathogenesis of winter dysentry in cows?

Answer 22

Fecal-oral
Sudden explosive outbreaks of diarrhea, dark green to black colored feces, dehydration, decline in milk production
Similar to calves, causes diarrhea–in severe cases, hemorrhage and hyperemia of colonic and cecal mucosa can cause death

Question 23

What group does FIP belong in?

Answer 23

1a

Question 24

How is FIP transmitted?

Answer 24

It is shed in feces, transmitted through the fecal oral route (but can also be transmitted through placentas or inhalation)

Question 25

What could happen to a cat infected with feline coronavirus?

Answer 25

Resistant: 5-10%
Transient (mild diarrhea): 70%
Persistent carrier: 5-10%
FIP: 1-3%

Question 26

What is the role of CMI in FIP?

Answer 26

Strong response: prevents FIP
Weak CMI and strong humoral: effusive (wet) FIP–> peritonitis, pleuritis, vasculitis, ascites, glomerulonephritis, IV coagulation
Intermediate response: non-effusive, dry form of FIP–> small granulomas, ocular lesions, CNS involvement

Question 27

Describe the pathogenesis of FIP

Answer 27

Spike proteins/antibodies attach to FIPV receptor (CD13) on macrophages, infect them, infection gets disseminated
Can replicate in monocytes or macrophages
Immune complex formation can also happen activating the complement system and causing the ‘wet’ form of FIP

Question 28

Signs of effusive FIP

Answer 28

Distended abdomen, diffuse fibrinous peritonitis, ascites, pyogranulomatous in liver or intestines, pleuritis, thoracic effusion, omental pyrogranulomas

Question 29

Signs of dry FIP

Answer 29

Granulomatous inflammation in lymph nodes, pyogranulomatous lesions on kidney, granulomatous meningoencephalitis, granulomatous uveitis

Question 30

Diagnosis of FIP?

Answer 30

Rivalta test: add 1 drop of acetic acid + 5 ml of water, add one drop of effusion to tube and if it dissolves, negative. If it retains shape, positive for FIP
ELISA, IFA, virus-neutralization tests for antibodies but not specific strains, immunofluorescence

Question 31

Treatment/prevention of FIP?

Answer 31

Vaccination not recommended

Question 32

What are the 5 types of avian infectious bronchitis (group 3)?

Answer 32

Respiratory (MAGC)*
Nephrotropic*
Enterotropic 
Proventricular 
Uterotropic

Question 33

What protein is responsible for antigenic variation/multiple serotypes in avian infectious bronchitis?

Answer 33

S protein

Question 34

How is infectious bronchitis virus (IBV) transmitted?

Answer 34

Aerosol/inhalation, direct contact, contact with contaminated shit from coughing, feces, or egg surfaces of infected chickens
Respiratory disease is more common but reproductive disorders resulting in a decline in egg production also occur

Question 35

What can enhance the severity of bronchitis in chickens?

Answer 35

Immunosuppression, E. coli, or Mycoplasma infection

Question 36

Signs of bronchitis virus nephritis?

Answer 36

White urates in swollen kidney, visceral gout, urates on liver, heart, nephritis, swollen kidney, urolithiasis, distended ureter

Question 37

Signs of IBV respiratory disease?

Answer 37

Inflammation of trachea and bronchi, white caseous exudate in syrinx and primary bronchi, congestion/hemorrhage in trachea, depression, ruffled feathers, gasping, dyspnea

Question 38

Signs of infectious bronchitis reproductive disorder?

Answer 38

Soft shelled, mishapen discoulored eggs, thin albumin, involuted, flaccid ovarian follicles, stunting or dwarfing of embryo

Question 39

Control of infectious bronchitis virus?

Answer 39

Proper hygeine duh
Live vaccines: meat type chickens for initial vaccination, M41 strain
Inactivated vaccines: for layers and breeders, administered via subq inoculation at 13-18 wks

Question 40

What shape is the Torovirus nucleocapsid?

Answer 40

A goddam doughnut

Question 41

Bovine torovirus: what about it?

Answer 41

Doughnuts make your stomach hurt so gastroenteritis
AKA Breda virus
Serotypes 1 and 2
Occurs frequently in 2-5 day old calves
Transmission: fecal-oral, sometimes nasal
Calves up to 4 mos are susceptible
Infects epithelial cells from lower half of vili, extending into crypts; also surface and crypt epithelium in large intestines
Malabsorption, diarrhea, duh