Calcivirus Flashcards
Vesicular Exanthema of Swine
Species affected
- Sea lions and other aquatic animals (whales, dolphins, seals, fish) are the natural hosts
- Swine are the accidental hosts
- Currently eradicated in swine!
- Fox, Mink, Monkeys and Humans (zoonotic) are also susceptible to get the virus from the vesicles
Vesicular Exanthema of Swine
Most susceptible
Seals
All age groups
Vesicular Exanthema of Swine
Occurrence
1950s: swine cases in USA
Nowadays: present in seals in the Pacific costal region of America
Vesicular Exanthema of Swine
Spread
Spread by ingestion of raw meat of sea mammals and fish or by excretions of infected animals (saliva, vesicles
Less contagious than FMD
Vesicular Exanthema of Swine
Pathogenesis
Swine: PO infection —> mouth, snouts, limbs
Vesicular Exanthema of Swine
Primary replication
Swine: 1-4 days incubation period
Vesicular Exanthema of Swine
Clinical signs
Swine: • Fever, Anorexia, Depression • Vesicles on mouth, snouts and limbs —> lameness • Lesions heal rapidly • Low mortality in piglets Seals: • Skin lesions • Abortion • Perinatal mortality
Vesicular Exanthema of Swine
Diagnosis
Clinical signs —> suspicion of disease but further testing required since it is a notifiable disease
Detection of virus: PCR
Virus isolation
Detection of antibodies: ELISA
Vesicular Exanthema of Swine
Treatment
No effective treatment
Vesicular Exanthema of Swine
Prevention and immunity
Outbreak: Restriction zones
and eradication zones
Prevention: Heat treatment of seafood and fish meals before fed to pigs
Feline Calicivirus Infection
Species affected
- Domestic cat and other felids (ex cheetah), Marine mammals
* Rarely dogs
Feline Calicivirus Infection
Most susceptible
All age groups
Feline Calicivirus Infection
Occurrence
Worldwide
Frequently in shelters and breeding catteries
Feline Calicivirus Infection
Spread
*Spreading by direct contact
with infected animals or excretions
*Indirect transmission occurs but is less frequent —> aerogenous way is the most common indirect transmission
Feline Calicivirus Infection
Pathogenesis
Oronasal Infection —> pharynx —> Viraemia —> Other organs:
• Lungs —> alveolitis, exudative pneumonia, proliferative interstitial pneumonia
• Mouth, throat, nose/paw pads—> blisters, epithelial necrosis—> erosions, neutrophil infiltration
• Joints —> acute synovitis, thickened synovial membrane, liquid accumulation
• Very virulent strains are systemic and propagate in visceral organs too
*Virus is shed by the faeces and urine. Virus is also airborne.
*Persisting infections in the tonsils and nasopharyngeal mucosa
*Some virus strains: long term carrier and continuous shedder cats
• A least for 30 days after overcoming the infection
• 50% of cats are carriers on day 75 after overcoming infection
• Some cats are life-long carriers and shedders (20 30% of cats)
*FIV, FeLV facilitate shedding Shedders can be low, intermediate or high titre
Feline Calicivirus Infection
Primary replication
- Upper Respiratory Tract —> Pharynx
* Incubation period of 3-4 days
Feline Calicivirus Infection
Target organs
Lungs, mouth, throat, joints, visceral organs
Feline Calicivirus Infection
Clinical signs
*After viraemia —> fever, mild depression —> secondary fever can be caused by lesions and signs
*Differences in virulence and tissue-tropism —> different clinical manifestations:
• Oral signs:
• Erosions in the oral cavity
• Mainly on the margin of tongue, lips, nose
• Also on nose/paw pads
• Rarely on skin
• Healing within 2-3 weeks
• Respiratory signs:
• Mild respiratory and conjunctival signs —> sneezing, clear lacrimation, nasal discharge,
• Rarely pneumonia, dyspnoea, salivation, wet fur
• Limping Syndrome:
• Lameness and fever
• Can be independent from oral and respiratory signs
• May be immunocomplex mediated
• Associated with depression and pneumonia
• Usually complete recovery within 24-48 hours
• Has been observed after immunisation with life attenuated vaccine
• Severe Systemic Syndrome:
• Virulent FCV strains
• Vasculitis, face and nose/paw pad lesions, fever, respiratory signs, icterus, nose and intestinal bleeding
• Up to 60% lethality
• More severe in adults, occurs in vaccinated cats too
• Chronic Stomatitis: Lymphoplasmic Gingivitis Stomatitis Complex (LPSG):
• Most of the patients are FCV shedders but other factors (such as FIV) may contribute
Feline Calicivirus Infection
Pathology/Histopathology
*Erosions in the oral cavity, at the margin of the tongue
*Very virulent strains:
• Vasculitis
• Enlarged lived
• Pneumonia
• Pancreatitis
• Pericarditis
Feline Calicivirus Infection
Diagnosis
- Clinical signs may cause suspicion of disease but not always
- Oral, pharyngeal, tonsil swab for ELISA, IF, RT-PCR and virus isolation
- Serology is not useful as calciciviruses are wide spread and almost all cats are seropositive
Feline Calicivirus Infection
Treatment
*Supportive treatment, enteral nutrient, parenteral fluid, antibiotics, hyperimmune sera
• NSAIDs
• Antibiotics for prevention of secondary bacterial infection
• Hyperimmune sera used only in early stage of disease as if used later in infection the diesel can get worse due to immunocomplex formation
Feline Calicivirus Infection
Prevention and immunity
*Maternal antibodies protect for a few weeks, may persist for 10-14 weeks
*Hygiene and management: closed farming, identification of shedders
*Vaccine:
• Attenuated and inactivated vaccines, usually bivalent (FCV and FHV)
• Residual virulence, shedding of attenuated strain
• The strains of calicivirus are all different meaning that vaccination will only protect against the strains vaccinated for and not the others
• Commercial vaccines have a relatively broad spectrum of protection (225 strains)
• Primary vaccination at 9, 12 and 16 weeks of age and then yearly
• Vaccination may protect from clinical signs but not from infection and becoming a carrier
Rabbit Hemorrhagic Disease
Species affected
RHDV-1: Rabbit only (Oryctolagus cuniculus)
RHDV-2: Rabbit and Hare (Lepus eurupaeus)
Rabbit Hemorrhagic Disease
Most susceptible
RHDV-1: Rabbits over 2 months of age
RHDV-2: Younger rabbits also susceptible, mostly in pet rabbits, in autumn
