Coronaviridae

Question 1

Describe coronaviridae.

Answer 1

-icosahedral internal core structure enclosing a helical nucleocapsid (corona virus) OR tightly coiled tubular nucleocapsid bent into doughnut shape (torovirus)

Question 2

Describe transmissible gastroenteritis (TGE) in pigs.

Answer 2

-OIE LIST B DZ & reported in the USA
-highly inf viral dz of pigs
-vomiting, dehydration, diarrhea, high mortality in piglets
-older piglets sus but mild CS

Question 3

Describe the 2 forms of TGE in pigs.

Answer 3

1. Epidemic form
   -virus is first introduced into sus herd & observed most often in winter
   -rapid spread, high morbidity & mortality in piglets
2. Endemic form
   -virus persist in partially immune herd or due to concurrent porcine respiratory coronavirus (PRCV) inf (deletion mutant of TGEV)
   -less severe form of dz & lower mortality or morbidity

Question 4

Describe the transmission of TGE & pathogenesis.

Answer 4

1. Transmission
   -unclear
   -fecal oral (mainly)
   -aerosol
2. Pathogenesis
   -villus atrophy = malabsorption

Question 5

Describe porcine epidemic diarrhea (PED).

Answer 5

-caused by corona virus group 1b
-CS similar but PEDV unrelated to TGEV (group 1a)
-spread via fecal oral in US = economical loss
-acute outbreak of severe diarrhea, vomiting

Question 6

Describe porcine hemagglutinating encephalomyelitis (vomiting & wasting dz in pigs).

Answer 6

1. Vomiting & wasting dz (VWD) form
2. Encephalomyelitic form

Question 7

Describe bovine coronavirus infection in calves.

Answer 7

-diarrhea in calves (1d to 3mo of age but mostly 1-2wks)
-common during winter

Question 8

Describe winter dysentery in cows.

Answer 8

1. Etiology
   -bovine coronavirus
2. Transmission
   -fecal oral
3. CS
   -diarrhea (sudden & short outbreak)
   >dark green to black feces w blood flecks
   -dehydration, coughing, dec in milk prod

Question 9

Describe feline infectious peritonitis (FIP).

Answer 9

Non effusive or dry form
-granulomatous uveitis
-keratic precipitated on inner cornea

Question 10

Describe the diagnosis, CS, & vaccine of FIP.

Answer 10

1. Diagnosis
   -effusion analysis: rivalta test in test tube + 1 drop 98% acetic acid + 5ml distilled water & mix + 1 drop of effusion to tube
   >if drop disappears & solution is clear = NEG for FIP
   >if drop retains shape & drops down or attached to surface of tube = POS for FIP
2. CS
   -ELISA, IFA, virus neutralization test detect presence of corona virus Ab in cat BUT cant differentiate between strains of feline coronavirus
3. Vaccine
   -intranasal
   -NOT REC

Question 11

Describe avian infectious bronchitis.

Answer 11

-common, highly contagious, acute, economically imp viral dz of chicken caused by coronavirus inf bronchitis virus (IBV)
-VACCINE:
A) live
-meat type (broiler) chickens for initial vacc & priming of breeders & layers pellets
B) inactivated
-use in layers & breeders

Question 12

Describe Toroviruses.

Answer 12

-named after unique shape of nucleocapsid = doughnut shaped
-cause gastroenteritis in mammals, primarily cattle
-fecal oral

Question 13

Describe bovine toroviruses.

Answer 13

‘Breda virus’
-cause profuse diarrhea in young calves