Coronaviridae Flashcards
Know characteristics of Coronaviridae family
What families are included in the Nidovirales Order?
Coronaviridae, Arteriviridae, Roniviridae, Mesovirinae
What subfamilies comprise Coronaviridae family?
Coronavirinae and Torovirinae
What is distinct about the transcriptions strategy of Nidovirales Order viruses?
All use a distinct “nested set” transcription strategy, where the expression of genes encoding structural viral proteins is mediated via a nested set of 3’ coterminal subgenomic mRNAs
Which genera comprise the Coronavirinae and Torovirinae subfamilies, and give an example of viruses in each genera?
Coronavirinae: Genus Alphacoronavirus (FIP, TGE, Canine, PED), Betacoronavirus (Bovine, Canine resp, SARS, MERS), Gammacoronavirus (IBV), and Deltacoronavirus (Porcine deltacorona).
Torovirinae: Torovirus (Breda virus) and Bafivirus
What are the characteristics and the sizes of the Coronavirinae and Torovirinae subfamilies?
Genome of Coronaviridae is a single molecule of linear positive-sense, single stranded RNA, 27-31kb for Coronavirinae and 25-30kb for Toroviruses, the largest nonsegmented RNA viral genomes
What are the envelope proteins of Corona and Torovirinae viruses?
Spike, major and minor transmembrane proteins, and some have hemmaglutinin esterase prot (HE) small spike
Which is the pig age group most susceptible to TGE infection and why?
Neonates are more susceptible. Reasons: gastric secretions are less acidic, renewal of enterocytes is slower, immune system is naive, very susceptible to electrolyte disbalance due to diarrhea.
How does TGE transmit?
Fecal-oral transmission, due to introduction of new pigs secreting the virus or fomites.
What is the difference betwen TGE virus and porcine respiratory coronavirus?
Porcine respiratory coronavirus is an S gene deletion mutant, that changed tropism from enteric to respiratory tissues. Deletion is 621-681 nt in size. Less virulent.
