Which of the following is not consider to be a slow viruse diseases ?
Ans. is `d' i.e., Sarcoidosis SLOW VIRUS DISEASES . A group of infections in animals and human beings characterised by a very long incubation period and a slow but relentless course, terminating fatally . Characteristics of slow virus infections: Incubation period ranging from months to years Course of illness lasting for months or years, with remissions and exacerbations Predilection for involvement of the CNS Absence of immune response A genetic predisposition Invariably fatal termination . Slow virus diseases are classified into three groups. 1. GroupA - Slowly progressive infection of sheep. - Caused by lentiviruses - Examples --> Maedi, Visna 2. Group B -Also known as Prion diseases collectively known as the subacute spongiform viral encephalopathies - Chronic progressive diseases of CNS - Infectious agents are proteins (Prion) devoid of DNA and RNA - Prion proteins are unusually resistant to physical and chemical agents, such as heat, irradiation and formalin. - Pathogenic mechanism : . Proliferation of an abnormal prion protein (Pr PSc) which is derived from the normal prion protein (Pr Pc) . The accumulation of Pr PSc in the CNS as diffuse deposits and in the form of plaques disrupts the architecture and function of the brain, causing disease. - Pathology . Progressive vacuolation in the dendritic and axonal processes of the neurons . Extensive astroglial hyperophy and proliferation . Spongiform degenration in the grey matter. . No inflammation
Kuru
Scrapie
Creutzfeldt Jakob disease
Sarcoidosis