REOVIRAL INFECTIOUS DISEASE OF CATTLE AND GOATS ALSO CALLED SORE MUZZLE AND DANCING DISEASE

1. Blue tongue
ABHIJITH SP
CVAS POOKODE

2. INTRODUCTION
• Infectious arthropod borne viral disease of cattle ,sheep and goats.
• Although sheep are most severely affected, cattle are the main mammal
reservoir of the virus and are critical in the disease epidemiology.
• The disease is non-contagious and is only transmitted by insect vectors
(midges of the Culicoides species).
• Bluetongue virus is a notifiable disease in many countries.
• Synonyms: Sore muzzle, Dancing Disease
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3. AETIOLOGY
• Reoviridae Family- Orbivirus genus- BTV.
• Genome consists of dsRNA, divided into 10-12 segments
• Cytoplasmic replication, with formation of large intracytoplasmic perinuclear
inclusion bodies.
• Nonenveloped, spherical virions.
• The BTV genome evolves rapidly via mutations.
• Orbi-Orbit or stoma region.
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4. SUSCEPTIBLE HOST
• BTV affects sheep, cattle, deer, goats and camelids (camels, llamas, alpacas,
guanaco and vicuña).
• Humans are not affected.
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5. TRANSMISSION
• Bluetongue is a noncontagious disease.
• Transplacental transmission occurs in cattle and sheep. Semen that contains
RBC or WBC infected with the virus may infect susceptible cattle.
• Culicoides spp. [biting midges, no-see-ums], especially Culicoides variipennis var
sonorensis, are the biological vectors.
• Culicoides spp. usually feed at dawn and dusk and they require standing water in
which to breed.
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6. INCUBATION PERIOD
• 6-10 days.
• Morbidity: Up to 80%; mortality: up to 50%.
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7. PATHOGENESIS
• Through biting of Culicoides, they gain access into blood vessels .
• They multiply in endothelial cells and WBC.
• They break the cell and comes out and create a gap in endothelium.
• So Protein rich fluid oozes out through that—Oedema
• Rbc moves out-Hemorrhage
• Followed by thrombosis and infarction.
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8. CLINICAL SIGNS
• Fever, ulcerated mouth, cyanosis of tongue [bluetongue], profuse salivation
and frothing, and nasal discharge [serous, later becoming mucopurulent].
• Coronitis and laminitis resulting in lameness and recumbency.
• Fetal infection. Fetal death and/or abortion; CNS malformations such as
hydranencephaly; porencephaly, etc.
• Cyanosis of tongue-Thus the name Blue Tongue.
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Darkly congested gingiva

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Foot
Coronitis
Ulceration and necrosis of teats

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Coronary Band Lesions
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Ulcerative Dermatitis

14. MACROSCOPIC LESIONS
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Brain vasculitis haemorrhage

15. MACROSCOPIC LESION
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Intimal Haemorrhage on pulmonary artery

16. MACROSCOPIC LESION
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Focal haemorrhage on pulmonary artery

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Hydrocephalus

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Aspiration Pneumonia

19. MICROSCOPIC LESIONS
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Intracytoplasmic inclusion body in epithelial cells of mouth

20. MICROSCOPIC LESIONS
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Skeletal Cell Necrosis

21. DIAGNOSIS
• Virus isolation. Heart blood [washed RBCs or buffy coat], spleen, liver, etc.
IV inoculation into 10- or 11-day-old chicken embryos or cell culture.
• Antigen and nucleic acid detection. ELISA, FAT, immunoperoxidase,
immune electron microscopy, PCR, etc.
• Seroconversion [acute and convalescent sera].
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22. PREVENTION AND CONTROL
• Bluetongue is a notifiable disease. Sheep should be put in barns at dusk [prime
Culicoides feeding period].
• Vaccination. Attenuated monovalent virus vaccines to serotypes 10, 11, and
17 are used in the United States.
• Attenuated vaccines should not be used in pregnant animals; or during the vector
season because the vectors may pick up the vaccine virus and transmit it to
other animals.
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24. FACTS AND TIPS.
• Serotype of BTV-29.
• REO=Respiratory Enteric Orphan
• Immunity is serotype specific.
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25. THANK YOU