Final Exam - Reoviridae Flashcards
Genus Orbivirus
African horse sickness virus, Bluetongue virus
Genus Orthoreovirus
Avian reovirus multiple serotypes
Genus: Rotavirus
RVA (Group A Rotavirus)
Blue Tongue Virus
An infectious non-contagious, insect-borne disease of domestic and wild ruminants
Blue Tongue Virus Hosts
Most susceptible and common - Sheep and white tailed deer
Inapparent Infection - Cattle, goats and some wild ruminants.
List A Disease
Blue tongue virus is a list A disease in the OIE. They are transmissible diseases that have the potential for very serious and rapid spread, irrespective of national borders, that are serious socio-economic or public health consequence and that are of major importance in the international trade of animals and animal products.
Blue Tongue Virus Genome
Consists of ten segments of double stranded RNA (dsRNA)
Transmission - BTV
Arthropod (Insect)-borne transmission. Transmitted by certain species of Culicoides, a biting midge.
Can also be transmitted trans-placentally and venereal transmission.
Pathology of BTV
- Damage to vascular endothelium
- Intravascular coagulation
- Necrosis of tissues and organs supplies by damaged capillaries
- Edema
- Hemorrhage
- Congestion
- Abortion (abortive form of BTV disease in enzootic areas)
- CNS malformations
Clinical Findings of BTV in Sheep
Severe febrile reaction. Profuse salivation, edema of muzzle, reddening of nasal mucosae. Mucopurulent nasal discharge, often blood stained. Crust formation on nostrils and lips. Linear erosion and reddening of the buccal mucosa. Cyanosis, necrotic ulceration of ht etongue. Erosion of dental pad, necrosis, hyperemia, ulceration in oral cavity. Coronitis and laminitis causing lameness. Extensive facial swelling and aborted, macerated fetuses.
Clinical Findings of BTV in Cattle
Erosions in the buccal cavity, drooling of saliva. Hemorrhage and congestion of muzzle. Ulcerative glossitis and stomatisis. Serous to mucopurulent nasal discharges, erosions on the muzzle with sloughing of the mucosa. Ulceration of teats, coronitis and lamness, lachrymation, hyperemia and edema of conjunctiva, edema of face, abortion and congenital deformities.
Diagnosis of BTV
Clinical signs, virus isolation: by tissue culture of in developing chick embryos. Detection of Antigen (immunohistochemical tests, such as immunofluorescence, immunoperoxidase test). Detection of nucelic acid (polymerase chain reaction (PCR)). Detection of antibody (agar gel immunodiffusion test (AGID), competitive ELISA). Necropsy findings, histology.
Prevention of BTV
Attenuated vaccines which are serotype specific. Vector control.
African Horse Sickness (AHS)
List A infectious disease of the OIE. Infectious, non-contagious, arthropod borne disease of horses, donkey, and mules.
Transmission of AHS
Transmitted by Culicoides species that occurs regularly in most countries of sub-saharan Africa. At least two field vectors involved: C. imicola and C. bolitinos