62. Diseases of farm animals caused by orthoreoviruses and rotaviruses. Flashcards
Causative agents?
Rotavirus infections in domestic animals
Causative agents
- 9 species (A-J)
- 11 genome segment, frequent reassortments
‣ A: most mammals and birds are susceptible, 90% of human cases
‣ B: human, swine, cattle, sheep, rat
‣ C: swine, rarely human
‣ D: bird
‣ E: swine
‣ F: bird
‣ G: bird
‣ H: swine
‣ I: cats
‣ J: bats
- Resistant (pH 3), infectivity retained for months in environment
History/ Occurrence?
History, occurrence:
- First detection in calves w/enteritis(1969 USA)
- World-wide distributed, frequent
Epizootiology/ Pathogenesis?
Epizootiology, pathogenesis
- Faecal ➝ oral route: faeces, environment
- Not germinative, but present on the surface of egg
- Multiplication in enterocytes of few day old animals
- Mainly in the middle and distal regions of the small intestine ➝ shedding in faeces in high titres
- Epithelial damage ➝ villus atrophy ➝ osmotic diarrhoea, exsiccosis
- Simultaneous infections: parvovirus, coronavirus, astroviruses, E. coli, cryptosporidia
Clinical signs?
Clinical signs
- Mainly in 1 (2) weeks of age
- 24-48 hour incubation period
- Sudden massive diarrhoea
- Loss of appetite, weakening, retarded body weight gain
- Low mortality, mainly due to concomitant pathogens
- Recovery by the end of the second week
- If signs develop in older age ➝ usually more serious (immunosuppression in background)
Pathology, Histopathology?
Pathology, histopathology:
- Undigested, liquid content in the intestines, enlarged intestines
- Inflammation in the enteric mucosa
- Villus atrophy & blunting
Diagnosis?
Diagnosis
- Age (1st week of age), clinical signs ʹ suspicion
- Virus detection: RT-PCR, AgELISA, cc immune-electrophoresis, IF, serology, EM, iEM (Mat immunity!)
- Frequent simultaneous infectious with other pathogens!
Treatment, prevention and control?
Treatment, prevention, control
- Supportive/electrolyte therapy (possible parenteral)
- AB against bacterial co-infections
- Hygiene (parturition, hatching, litter, individual keeping)
- Sufficient colostrum uptake
- Inactivated, usually polyvalent vaccines (+corona, parvo, E. coli K99) - vaccination of pregnant cows
- twice in the 3rd trimester
Seadornavirus-associated diseases ʹ Reoviridae, Sedoreovirinae, Seadornavira genus ?
Seadornavirus-associated diseases ʹ Reoviridae, Sedoreovirinae, Seadornavira genus
- Causative agents
- S.E Asia dodeca RNA virus (Banna virus, kadipiro virus, Liao Ning virus)
- 12 genome segment (dodeca)
- Culicidae vectors
- Occurrence: China, Java, Indonesia
- Pathogenesis, symptoms
- Human pathogen but detected in animals too
- Influenza-like illness, fever, muscle & joint pains
- Encephalitis
- Zoonotic potential is unknown
Orthoreovirus infections of domestic animals ʹ Reoviridae, Spinareovirinae?
Orthoreovirus infections of domestic animals ʹ Reoviridae, Spinareovirinae
Causative agents:
- 5 sp. ʹ mammalian (4 serotypes), avian (11 serotypes), (baboon, bat, reptile)
- 10 genome segment, reassortments
- Mammalian orthoreovirus infections ʹ cattle & small Ru
- CATTLE: world-wide occurrence
- Shed in faeces & nasal discharge
- PO, air-borne infections Æ viraemia
- Mainly calves = mild enteritis, respiratory signs (pneumoenteriris)
- Bacterial co-infections: complications! Chronic bovine resp disease complex
- (contains reovirus also, Pasteurella multocida, Mannheimia, Histophilus somni)
- Colostrum Abs can protect the calves until the age of ~5 months
- Component of combined vaccines against respiratory disease of calves
- SHEEP: in the background of resp & enteric diseases of lambs
- HORSE: isolation from resp disease of foals, usually w/ bacterial co-infections ʹ coughing,
- nasal discharge
- SWINE: detection from diarrhoea & encephalitis cases ʹ zoonosis?
- RABBIT: diarrhoea of young animals