Final Exam - Rhabdoviridae Flashcards
Rhabdoviridae 4 genera with human and animal pathogens
Lyssavirus, Vesiculovirus, Ephemerovirus, Novirhabdovirus
Lyssavirus
Can cause rabies like disease in animals and humans. Bats are potential reservoirs.
Vesiculovirus
Viruses of horses, cattle, swine, and humans. Some have been isolated from fish such as carp and salmonids.
N protein
makes up the major capsid component, the viral nucleocapsid
P protein
is a cofactor of the viral polymerase
M protein
an inner protein that facilitates virion budding (binds N and G proteins)
L protein
Is an RNA dependent RNA polymerase (transcription and replication of viral RNA)
Virions are sensitive to
UV radiation from the sun, detergent based disinfectants and iodine containing solutions are effective disinfectants. Oxidizing agents, acids, aldehydes.
Rabies Virus
Infects all mammals. Skunks, raccoon, foxes, and wolves are reservoirs in North America. Most commonly vampire bats and silver-haired bats
Urban Rabies Cycle
Dogs are the main reservoir. This cycle predominates in areas of Africa, Asia, and Central and South America.
Sylvatic (of wildlife)
Cycle is predominant cycle in the northern hemisphere. It can also present simultaneously with the urban cycle in some parts of the world.
Clinical Phases of Rabies - Prodromal Phase
Aggressiveness in tame animals. Daytime activities in nocturnal animals. No fear of humans in wild animals.
Clinical Phases of Rabies - Excitative (fury) phase
Severe agitation and aggressiveness. Bites any material. High barking sound.
Clinical Phases of Rabies - Paralytic (dumb) phase
Inability to swallow. Excessive salivation. Hydrophobia in dogs. Complete paralysis is followed by death.
Pathogenesis and Pathology of Rabies Virus
Virus binds to receptor for acetylcholine at neuromuscular junctions.
Diagnosis of Rabies Virus
Tissues from two locations in the brain (the brain stem and cerebellum). Performed only in reference laboratories.
Rabies Virus - Laboratory Diagnosis
Immunochemical identification of rabies virus antigen
Rabies Virus - Control
Vaccines are available.
Vesiculovirus - Vesicular Stomatitis Virus (VSV)
Infects cattle, swine and horses. Causes vesicular stomatitis. REPORTABLE/ ZOONOTIC DISEASE!
VSV - Clinical Features
Salivation, fever are first signs in cattle and horses. Lameness is a first sign in swine. Vesicles on tongue, oral mucosa, teats, coronary bands (cattle and swine). In horses tongue lesions are most pronounced.
VSV - Pathogenesis
Virus enters the body through mucosal or skin abrasion. Virus replicates in intraepithelium of mucosae and skin.
VSV - Epidemiology
Virus is transmitted by biting insects such as sand flies, black flies, house flies, and mosquitoes.
VSV - Diagnosis
Clinically indistinguishable from other vesicular diseases of swine and cattle (e.g., foot and mouth disease). Vesicular lesions in horses are only characteristic of VSV infection. Only reference laboratories can do diagnostic testing.
VSV - Prevention and Control
Control or flies. Inactivated or attenuated virus vaccines have been tested but not yet available commercially.
Novirhabdovirus
Viral hemorrhagic septicemia virus. Infectious hematopoietic necrosis virus.
Vesiculovirus
Spring viremia of carp virus. Pathogens of wild and cultured fish.
Viral hemorrhagic septicemia virus - Clinical Signs
Darkened body color, exophthalmia, hemorrhage at base of fins. Distention of abdomen due to ascites.
Viral hemorrhagic septicemia virus - Diagnosis
There is no commercial vaccine available
Bovine ephemeral fever virus
Ephemerovirus. Not reported in north and south america.
Bovine ephemeral fever virus - Clinical features
Seaons disease for summer and autumn, Biphasic or polyphasic fever. Immediate drop in milk production. Occasionally nasal and ocular discharges. Cessation of rumination. Constipation and abortion may occur. Infrequent diarrhea, temporary or permanent paresis.
Bovine ephemeral fever virus - Diagnosis
Gold standard - virus isolation in mosquito cell culture or suckling mouse brain. RT-PCR. Neutralization test. Immunofluorescence of gel diffusion.
Bovine ephemeral fever virus - Prevention
Gives long-lasting immunity. Animals born after the outbreak are susceptible to infection. Inactivated and attenuated virus vaccine is used. A recombinant baculovirus vaccine is available.
