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Coronaviruses and Herpesvirus (week 3)
Terms in this set (53)
Coronavirus structure and properties
• Positive stranded RNA, enveloped
• Endocytosis and exocytosis for enter and exit
• Club like spike proteins are distinctive
• Distinct to coronas: "nido" =nested, nested set of subgenomic RNA in cytoplasm
• Polypeptide mechanism
4 categories of coronaviruses
alpha, beta, gamma, delta
Coronavirus Pathogenesis (general)
- often limited to:
- two main clinical signs
- more stable in:
in epithelial cells of gut or respiratory tract, killing cells.
young or immuno naive animals
diarrhea or respiratory disease
fluids like milk
• An alphacoronavirus.
• Very common in swine belt of USA.
• Life threatening in piglets aged 2 weeks or less if born from naïve sow.
• Animals greater than 5 weeks of age usually recover.
• Signs reduced by maternal immunity.
Transmissible gastroenteritis of swine (TGEV)
TGEV infects epithelium at
villus tips, killing them. Can be fusion of villi.
whats the route of transmission for TGE and whats the main threat in this disease
• control is very difficult, dogs and cats can be infected and spread virus through feces
• most effective: all in all out operation with SPF (specific pathogen free) pigs
applies to what virus?
is there a "natural vaccine" for TGE?
• Alphacoronavirus, genetically similar to TGE but in a different sub-group
• Closest virus relatives are in bats and humans
Porcine Epidemic Diarrhea Virus (PEDV)
Porcine Epidemic Diarrhea virus's clinical signs are identical to
Transmissable gastroenteritis of swine (TGE)
2 diagnostic tests for Porcine Epidemic Diarrhea virus
• PCR with specific primers, other than those for TGE
• Relatively easily isolated in cell culture (with trypsin to cleave the spike protein)
Novel Swine Enteric Coronaviruses (SeCoV) is a combo of
TGE and PEDV
• Vomiting and wasting disease
• Virus is common but disease is infrequent
• Spread by respiratory route
• Invades respiratory and GI epithelium
• Can migrate up axons to sensory ganglia spreading to brain and causing cell death
• Paddling, hyperesthesia and tremors
Porcine Hemagglutinating encephalomyelitis virus (PHEV)
• Causes calf scours
• Calves less than 2 months old
• Very common
• Replicated in epithelial cells at tips of villi
• Diarrhea, usually mild. Recover in 4-5 days, occasional shock/dehydration
Bovine coronavirus (BCoV)
Control of bovine coronavirus includes:
• Vaccines are available but are most effective in vaccinating the cow to boost maternal immunity
• Freezing colostrum from hyperimmune cows for eventual oral delivery to sick calves may reduce clinical signs
Major differentials for bovine coronavirus are:
Bovine rotavirus and cryptosporidia.
Less common - E.coli, salmonella. More than one of these may be involved
Bovine coronavirus is increasingly associated with
respiratory disease, shipping fever
• Disease of adult cattle especially in winter (in the northeast)
• Bloody diarrhea, low mortality
• When a newly arrived calf sheds bovine coronavirus
• Adult cows are poorly immune or naïve
no direct link to BCoV
causes GI disease in foals, but also adult horses can have respiratory disease
two biotypes of the same feline virus (alphacoronavirus family)
Feline Enteric Coronavirus (FECV) and Feline Infectious Peritonitis Virus (FIPV
FCoV also exists in two serotypes
type 1 and 2
Either serotype can exist as the FECV or FIPV biotype T/F
Type __ viruses are by far the most common infections in cats.
Virus isolation is possible with type _ viruses, not with type _ viruses
2, but not 1
Feline Enteric Coronavirus (FECV)
-transmission from cat-cat?
FIP is just a disease in kittens (T/F)
FIP transmits well from cat to cat (T/F)
Two main targets in FIP pathogenesis:
macrophages and vasculature inflammation leading to vascular compromise
FIP, Clinical Signs, wet form:
• Prolonged fever, inappetence, weight loss, unkempt appearance, occasionally icteric membranes
• Polygammopathy (increased IgG in blood leads to decreased albumin to globulin ratio. If A/G < 0.4 indicates FIP is quite likely, provided that albumin is normal).
• Characteristic sticky fluid with very high protein content in peritoneum or thoracic cavity.
• Signs related to the presence of this fluid (dyspnea, abdominal fluid wave).
• Pyogranulomas on viscera, especially small intestine and kidney
FIP, Clinical signs, dry form:
• Persistent fever, inappetance, weight loss, occasionally icteric membranes.
• Pyogranulomas on viscera, especially small intestine and kidney, and in retina.
• Uveitis (synechiae). Hyphemia. Neurological signs. Hydrocephalus (detected on MRI).
Clinical signs of dry form FIP will depend on location of ______
The ____ form is more acute, often with rapid onset and progression
The ____ form can take months to progress and can be very hard to diagnose
Rivalta's test useful for diagnosing what virus based on high protein content of the effusion
Gold standard of diagnostic test for FCoV/FIP
• Classically, synergistic with _______, causing very severe and life threatening diarrhea
Canine coronavirus also exists in two serotypes (like FCoV) but differ from FCoV because
the serotypes circulate extensively, often as co- infections (alphacoronavirus).
no evidence of FIP-like disease in dogs, despite similar initial infection (T/F)
• Novel coronavirus (reservoir thought to be birds, not bats); closest relative is Asian leopard cat CoV.
• First discovered in Ohio and Indiana in February 2014, rapidly spread to other states in the United States and Canada, and caused significant economic loss in the swine industry.
• Similar clinical signs to PEDV and TGEV ; additional stomach lesions.
Porcine deltacoronavirus isolation where?
in swine testicle (ST) cells.
Large, double stranded DNA, enveloped
• Reactivation: when latent virus re-enters the productive replication cycle. Can happen at any time.
• Viral latency differs from clinical latency.
primary infection sites vs secondary infection sites of Herpesvirus
epithelial/mucosal surfaces → primary clinical signs
central nervous system/pregnant uterus → secondary clinical signs
properties that help herpes hide form immune system:
• Variety of immune evasion strategies
o viral proteins binding chemokines (gG)
o viral proteins mimicking cytokines (vIL-10)
o downregulation MHCI and MHCII (pUL56, UL49.5)
3 major routes of transmission for herpes:
1) via secretions of acutely infected animals
2) via latently infected "carrier" animals (reactivated)
3) via contaminated fomites and persons
3 subfamilies fo herpesviruses
alpha, beta, gamma
• Causes the most disease of the 3 subfamilies.
• Productive infection usually in mucosal epithelial cells.
• Short replication cycle.
• Latent infection primarily in sensory neurons, although there are exceptions (eg. EHV-1 and MDV: leukocytes).
• Productive infection in many different cell types
• Slow replication cycle
• Latent infection in monocytic precursors in bone marrow
• Also called 'cytomegaloviruses' because cells fuse into giant, multinucleated cells
• Humans: little disease in immunocompetent individuals, medically important in immunosuppressed patients (eg. AIDS patients, organ transplant patients)
• Animals (wild): bats, macaques, elephants → EEHV
• Humans: chronic infections ranging from asymptomatic to tumors (sarcoma, lymphoma).
• Animals: many, but only a few are of importance in veterinary medicine (MCF, EHV-2 & -5).
• Productive infection primarily in lymphoid cells, but also possible in epithelial cells and fibroblasts.
• Variable replication cycle.
• Latent infection in lymphocytes
• Alpha virus
• Most important in puppies 2 weeks or younger
• Most common signs in adults is NO SIGNS → establishment of latency
• Lesions -
o Enlarged lymph nodes
o Swollen spleen
o Focal necrosis and hemorrhages
Canine Herpesvirus Type 1
Whats unqiuely seen on histpathology for canine herpesvirus?
intranuclear inclusion bodies
Differential diagnosis "puppy death", canine herpes
1) infectious canine hepatitis (CAV-1) (but thickened, edematous gallbladder)
2) canine distemper (but no quick and sudden death)
Is there a vaccine for canine herpesvirus?
if you keep puppies warm up to 4 weeks of age they'll be less likely of contracting what virus?
canine herpesvirus type 1
This set is often in folders with...
Immunology and bacteria (week 3)
Viral Respiratory Diseases (week 2-3)
Bunyaviruses and Arenaviruses (week 3)
Respiratory Tract Infections (week 3)
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