Final: Coronaviridae Flashcards
Structure of coronaviridae
Icosahedral internal core structure enclosing a helical nucleocapsid (Coronavirus) or a tightly coiled tubular nucleocapsid bent into a doughnut shape (Torovirus)
Definition of Transmissible Gastroenteritis (TGE) in pigs
Highly infectious viral disease of pigs characterized with vomiting, dehydration, diarrhea and high mortality in piglets. Older pigs are also susceptible, but often exhibit milder clinical signs
Classified as “OIE List B disease”
Etiology of TGE in pigs
Genus Coronavirus of the family Coronaviridae
What is the epidemic form of TGE?
When the virus is first introduced into a susceptible herd, and is observed most often in winter. Rapid spread, high morbidity and mortality in piglets
What is the endemic form of TGE?
When virus persists in a partially immune herd, or due to concurrent porcine respiratory coronavirus (PRCV) infection (a deletion mutant of TGE virus). Less severe form of disease and much lower mortality or morbidity
Has TGE been reported in the USA?
Yes
What is the mode of transmission for TGEV?
Not clear, but fecal-oral transmission appears to be a major route of transmission. Can also be spread by aerosol.
What is the pathogenesis of TGEV?
Normal intestinal villi -> (enter TGE virus) Villus atrophy results in malabsorption-> diarrhea
Normal intestinal vili-> blunting and fusion of intestinal vili -> marked villus atrophy and fusion
Transmissible Gastroenteritis (TGE) in pigs causes what?
Incubation period: 24-48 hours
Onset is sudden
Profuse diarrhea in piglets Vomiting Severe depression and dehydration Water, yellow-green stool with offensive odor Feces contain clots of undigested milk
Pigs with TGE will have distended intestines that will show what?
Translucent intestinal wall and fluid ingesta
What will be in the dilated stomach of pigs with TGE?
Undigested milk
T/F: Pigs with TGE will have bloated gut and there will be presence of gases and atrophy of intestinal villi
True
Porcine Epidemic Diarrhea (PED) is caused by what? Is PED related to TGE virus?
Coronavirus
No, even though the clinical signs are similar
How is PED spread? What does it cause?
Fecal-oral route
Acute outbreaks of severe diarrhea and vomiting
T/F: PED has had no effect in the US
False
It has spread quickly and has caused severe economic losses
What is the pathogenesis of porcine hemagglutination encephalomyelitis?
Infection -> replication in nasal mucosa -> replication in lungs, tonsils, small intestine -> spread via PNS to CNS -> replication in brain stem, cerebrum and cerebellum -> virus replication in ganglion distale vagi OR disturbance in gastric emptying -> vomiting and malnutrition (respectively) -> wasting
Can go from replication in the brain stem cerebrum and cerebellum straight to acute enchephalomyelitis
What disease is caused by Porcine hemagglutinating encephalomyelitis?
Vomiting and wasting disease in pigs
Virus + RBC = ?
Agglutination
What age group is most affected by wasting?
Usually piglets <4 week old
What age group is most effected by acute encephalomyelitis from vomiting and wasting disease?
Piglets <2 weeks old
The form of vomiting and wasting disease that piglets get depends on what?
Pathogenicity of strain, age and litter susceptibility
What are the two forms of Porcine hemagglutinating encephalomyelitis?
Vomiting and Wasting Disease (VWD) form
Encephalomyelitic form
What does Bovine Coronavirus infection cause in calves? When does infection usually occur?
Diarrhea (1 day to 3 months old, mostly 1-2 weeks)
More common during winder months