59. Coronaviral diarrhoea of cattle and dogs. Flashcards
Coronaviruses in Bovine epidemiology?
Coronaviruses in Bovine
Epidemiology
- Betacoronavirus 1
- At least 2 major types
- Unified antigen structure
- 1 serotype (strains can be different)
- HE protein
- Neutralisation Ab against S and HE
- Isolation on human tumor cell lines
- CP: syncytium, lysation
- Dog can be seropositive, turkey pipe can have mild diarrhoea
- Other ruminants
- Bind to sialic acid receptor, entry in MHCI
Pathogenesis?
Pathogenesis
- Viral intake: oronasal route
- Virus replication in bronchial and intestinal tract
- Viraemia
- Lasting virus shedding, disease formation: predisposing factors, course: secondary infections, IgA immunity: booster
effect
- Cell tropism: variability of S gene, receptors on cell surface and change with age
- Diarrheic form: small intestines, less colon and rectum
- Respiratory form: epithel cells of respiratory tract
Clinical signs ( Calves, weaner and adults) ?
Clinical signs
- Calves up to 3 weeks: calf diarrhoea (CD)
‣ Replication in villus epithelia
‣ Large farms
‣ Incubation: 2-6 days
‣ Watery diarrhoea: 2-6 days
‣ Occasional haemorrhage with high mortality
‣ Weakness, exsiccosis
‣ Co-infections with viruses (rota, adeno), parasites (Cryptosporidium), bacteria (E. coli)
‣ Immunisation of pregnant cows for maternal immunity
- Calf and weaner (feeder): respiratory
‣ 2-6 months old
‣ Fever, mucosal rhinitis, cough, dyspnoe
‣ Rhinitis, tracheitis, pneumonia (rare)
‣ Co-infections: viruses (PI-3, RS, IBR, adeno)
‣ Predisposing factors: transport, mixing herds
‣ Secondary bacterial infections: Pasteurella, Mycoplasma, Chlamydia
Adults: winter dysentery (WD)
‣ Dairy stock
‣ November-April after calving
‣ Morbidity: 50-100% (rapid spread), Mortality: 1-2% (dairy)
‣ Majority recover in 2-4 weeks
‣ Fever, loss of appetite, decreased milk production (25-95%)
‣ Profuse, watery, then haemorrhagic diarrhoea for 2-5 days
‣ Mild respiratory signs ➝ nasal discharge, coughing
‣ Necropsy ➝ haemorrhages in small and large intestines
‣ Reconvalescent immunity 1-5 years
Diagnosis and differential diagnosis of Bovine coronavirus?
Diagnosis
- Clinical signs
- Atg: IF, ELISA, RT-PCR, HA ʹnasal or pharyngeal discharge, faeces, lungs, intestinal mucosa
- Abs: HAG, ELISA, VN ʹPair of sera
Differential diagnosis
Young calves: Rota virus, E. coli, Cryptosporidiosis
Winter diarrhoea: BVDV, Salmonellosis
Respiratory signs: viral & bacterial infections
Coronaviruses in canine?
Canine enteric coronaviruses (59)
• 1971 Germany ➝ worldwide
Pathogen
- Alphacoronavirus
- 2 genotypes: I, II (IIa and IIb TGE recombinant)
- Recombinant types: CCoV-I x CCoV-II x TGE)
- Mainly young puppies
- Rapid spread
Pathogenesis?
Pathogenesis
- Viral intake: PO
- Viral replication: small intestine ➝ epithelial cells (on top of villi) destruction, rebuilding ➝ shortened villi
- Virus shedding: 6-9 days (occasionally 6 months) ➝ protecting IgA
Clinical signs of canine coronavirus ?
Clinical signs
Incubation: 1-4 days
- Loss of appetite, depression
- Vomiting, watery yellowish diarrhoea (bloody)
- No fever
- Healing: 8-10 days
Diagnosis and treatment of Canine Coronavirus ?
Diagnosis
- Anamnesis
- Isolation (genotype II)
- RT-PCR, IF
- Serology: VN (CCoV-II), ELISA, iIF
Treatment
- Heating, water and electrolyte replacement ➝ treatment of co-infections
- Combined inactivated vaccines
‣ From 6 weeks
‣ Between 6-12 weeks, 2-3 weeks apart, then repeat vaccine yearly
‣ Vaccines: TN449 strain, FEC-SAH (feline coronavirus)
Canine Pantropic Coronavirus Pathogen, Pathogenesis and Clinical signs?
Canine pantropic coronavirus
• 2005 Italy ➝ present in other countries
Pathogen
- Alphacoronavirus 1
- IIa genotype
- The S-protein is similar to FIP
- Rarely co-infection with CPV-2
Pathogenesis
- Viral intake: oronasal
- Viral replication: epithelial cells of lungs and intestines
- Viraemia ➝ damages the intestinal mucosa, airways, blood vessels, lymphoid tissues and other organs
Clinical signs
- 50-60 days old: typical clinical symptoms ➝ older have milder signs
- Fever (39.5-40℃), lethargy, inappetence
- Vomiting, haemorrhagic diarrhoea
- Lymphocytopenia
- Nasal discharge
- Neurologic signs ➝ ataxia, seizures, compulsive movements
- Death can occur within 2 days
- Subclinical infection sometimes
Pathology and Histopathology of Canine Pantropic?
Pathology
- Haemorrhagic enteritis
- Abundant serosanguineous fluid in abdominal cavity
- Haemorrhages and infarcts in lungs, liver, kidneys, surface of lymph nodes
Histopathology
- Epithelial cell degeneration in airways and intestines
- Interstitial pneumonia, alveolar oedema
- Necropsy in spleen
- Leukocyte depletion in lymph nodes
- Lesions in blood vessel walls all over body
Canine respiratory coronavirus History and Pathogen?
Canine Respiratory Coronavirus
- 2003 UK: sheltered dogs
- 2006 USA, Canada, Japan, Italy: serology
Pathogen
- Betacoronaviridae
- Close relative of BCoV (95% aa S gene) and human CoV
- HE protein
- Cold winter weather
- Rapid spread: breeders, pensions, shelters
Pathogenesis, clinical signs and diagnosis Canine respiratory coronavirus?
Pathogenesis
- Probably similar to BCoV
- Replication in intestinal epithelial cells not confirmed
Clinical signs
- Asymptomatic
- Mild respiratory ➝ mild fever, nasal discharge, coughing, sneezing
- Component of kennel cough
- Virus can be detected in faeces of vomiting-diarrhoeic animals
Diagnosis
- Direct viral detection ➝ isolation, RT-PCR
- Serology ➝ ELISA, HAG, VN
