Caliciviridae for veterinary students

FAMILY CALICIVIRID

AEKasahun Delenee VAR/5994/05

CALICIVIRUS• from the Latin calyx “chalice” or

Cup• Often referred as “Small round

structured viruses”

VIRION AND NUCLEIC ACID PROPERTIES

• non-enveloped• 27-40 nm in diameter• Icosahedral symmerty• Some have characteristic appearance with

32 cup shaped depressions on their surface

• Linear• Positive sense single-stranded RNA viruses

VIRION AND NUCLEIC ACID PROPERTIES

VIRION AND NUCLEIC ACID

PARTICLESEncompasses 4 clinical syndromes:• Swine Vesicular Exanthema• San Miguel Sea Lion Virus• Feline Calicivirus• Rabbit Hemorrhagic Disease

TAXONOMYGroup IV; single stranded RNA positive-strand virusesFamily: CaliciviridaeGenus: Lagovirus 

Nebovirus  Norovirus  Sapovirus  Vesivirus

REPLICATION1.Attachement to ho

st receptors mediates endocytosis of the virus into the host cell.

2.Uncoating, and release of the viral genomic RNA into the cytoplasm.

3.VPg is removed from the viral RNA, which is then translated into a processed ORF1polyprotein to yield the replication proteins.

4.Replication occurs in viral factories. A dsRNA genome is synthesized from the genomic ssRNA(+).

REPLICATION

REPLICATION5. The dsRNA genome

is transcribed/replicated thereby providing viral mRNAs/new ssRNA(+) genomes.

6. Subgenomic RNA translation gives rise to the capsid protein and VP2.

REPLICATION7. Assembly of new

virus particles and release by cell lysis.

DISEASES• Swine Vesicular Exanthema• San Miguel Sea Lion Virus• Feline Calicivirus• Rabbit Hemorrhagic Disease

Vesicular Exanthema infection of Porcine

DISEASES

Rabbit Hemorrhagic Disease

DISEASES

FELINE CALICIVIRUS

(FCV)

FELINE CALICIVIRUS(FCV)

a common respiratory disease in cats virus attacks the respiratory tract -- lungs and

nasal passages -- the mouth, with ulceration of the tongue, the intestines, and the musculoskeletal system

FELINE CALICIVIRUS (FCV)

Causative agent: Vesivirus

Clinical Signs: conjunctivitis rhinitistracheatis pneumona and

vesiculation,ulceration of the oral epithelium fever anorexia lethargy stiff gait

Nasal discharge and vesicles & ulcers on the tongue of a cat infected with FCV.

FELINE CALICIVIRUS (FCV)

Tongue ulcerative glossitis from a FCV case.

FELINE CALICIVIRUS (FCV)

Lesions: on muzzle and tongue, respiratory tract, oral cavity and eyes.

Pathogenesis: natural transmission occurs via aerosol and fomites; the virus is often carried to susceptible cats by human handlers.

FELINE CALICIVIRUS (FCV)

Radiographs of interstitial pneumonia.

FELINE CALICIVIRUS (FCV)

Histopathology & gross pathology of interstitial pneumonia from a FCV case.

FELINE CALICIVIRUS (FCV)

Lymphocytic-plasmacytic stomatitis in a cat.

FELINE CALICIVIRUS (FCV)

Lesions in the eyes

FELINE CALICIVIRUS (FCV)

SAMPLES AND TESTSDISEASES

CAUSATIVE

AGENT

SAMPLE/s DIAGNOSTIC TEST

SWINE VESICULA

R EXANTHEM

A

VESIVIRUS Vesicular fluid, mucous membranes

SEROLOGIC TESTELECTRON MICROSCOPY

FELINE CALICIVIR

US

VESIVIRUS oral swabs, blood, skin scrapings or lung

tissue

PCR, IMMUNOFLOURESCENCEENZYME IMMUNOASSAY

RABBIT HEMORRH

AGIC DISEASE

LAGOVIRUS Spleen, liver , blood IMMUNOFLOURESCENCEENZYME IMMUNOASSAY

SAN MIGUEL

SEA LION VIRUS

INFECTION

VESIVIRUS Tissue samples, fecal samples

ELISAImmunoflourescencePCR

CONTROL AND TREATMENT

FELINE CALICIVIRUS There is no specific treatment for FCV Antibiotics are used for secondary bacterial

infections, and immune modulators, such as lymphocyte T-cell immune modulator, have been used for immune support. 

Nursing care and rehydration are used for dehydrated and anorexic cats

Routine vaccination.

Avoiding overcrowding of feline populations, reducing stress.

THE END