Coronaviridae Flashcards
What are the viruses in Group 1a?
Feline infectious peritonitis/feline enteric coronavirus, canine coronavirus, transmissible gastroenteritis virus of swine, porcine respiratory coronavirus
What is the virus in group 1b?
Porcine epidemic diarrhea virus
What are the viruses in group 2a?
Porcine hemagglutinizing encephalomyelitis virus, mouse hepatitis virus, sialodacryoadentiis virus of rats (wtf), and bovine coronavirus
What viruses are in group 2b?
SARS in humans and cats, bats,
What viruses are in group 3?
Avian infectious bronchitis virus, turkey coronavirus, bluecomb virus
Describe the structure and genome of coronaviruses
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
Where do coronaviruses replicate?
Cytoplasm, virions are formed by budding/exocytosis
Which class does transmissible gastroenteritis in pigs (TGE) belong?
1a
Under which OIE class does TGE belong?
List B
What are the two forms of TGE?
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
Transmission of TGE?
Major route is fecal-oral but can also be spread by aerosol, contaminated objects, suckling milk from infected pigs
Describe the pathogenesis of TGE
Infects villi, causing villus atrophy and resulting in malabsorption. Then diarrhea
Clinical signs of TGE?
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
Diagnosis of TGE?
Necropsy, histopathology, antigen detection by FA, IHC, detection of nucleic acid by RT-PCR
What group does porcine epidemic diarrhea (PED) belong to?
Route of transmission?
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
What group does porcine hemagglutinating encephalomyelitis (vomiting and wasting disease) belong to?
2a
Describe the vomiting and wasting disease pathogenesis:
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
Clinical findings of the wasting and vomiting disease form?
Repeated retching and vomiting, anorexia, constipation, rapid emaciation, dehydration, cyanosis, comatose and death
Encephalomyelitic form clinical findings?
Muscle tremors, hyperesthesis, blindness, nystagmus, conuvulsions, death
What group does bovine coronavirus infection in calves belong in?
2a
Describe the pathogenesis of bovine coronavirus in calves?
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***
Describe the transmission, clinical signs, and pathogenesis of winter dysentry in cows?
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
What group does FIP belong in?
1a
How is FIP transmitted?
It is shed in feces, transmitted through the fecal oral route (but can also be transmitted through placentas or inhalation)
What could happen to a cat infected with feline coronavirus?
Resistant: 5-10%
Transient (mild diarrhea): 70%
Persistent carrier: 5-10%
FIP: 1-3%
What is the role of CMI in FIP?
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
Describe the pathogenesis of FIP
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
Signs of effusive FIP
Distended abdomen, diffuse fibrinous peritonitis, ascites, pyogranulomatous in liver or intestines, pleuritis, thoracic effusion, omental pyrogranulomas
Signs of dry FIP
Granulomatous inflammation in lymph nodes, pyogranulomatous lesions on kidney, granulomatous meningoencephalitis, granulomatous uveitis
Diagnosis of FIP?
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
Treatment/prevention of FIP?
Vaccination not recommended
What are the 5 types of avian infectious bronchitis (group 3)?
Respiratory (MAGC)* Nephrotropic* Enterotropic Proventricular Uterotropic
What protein is responsible for antigenic variation/multiple serotypes in avian infectious bronchitis?
S protein
How is infectious bronchitis virus (IBV) transmitted?
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
What can enhance the severity of bronchitis in chickens?
Immunosuppression, E. coli, or Mycoplasma infection
Signs of bronchitis virus nephritis?
White urates in swollen kidney, visceral gout, urates on liver, heart, nephritis, swollen kidney, urolithiasis, distended ureter
Signs of IBV respiratory disease?
Inflammation of trachea and bronchi, white caseous exudate in syrinx and primary bronchi, congestion/hemorrhage in trachea, depression, ruffled feathers, gasping, dyspnea
Signs of infectious bronchitis reproductive disorder?
Soft shelled, mishapen discoulored eggs, thin albumin, involuted, flaccid ovarian follicles, stunting or dwarfing of embryo
Control of infectious bronchitis virus?
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
What shape is the Torovirus nucleocapsid?
A goddam doughnut
Bovine torovirus: what about it?
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
