HEPATITIS A
TYPE A HEPATITIS Type A Hepatitis(infectious hepatitis) is a subacute disease of global distribution effecting mainly children and young adults. CLINICAL FEATURES : The large majority of infections are asymptomatic. Overt illness is seen in only about 5% . Incubation period is about 2-6 weeks. clinical disease consists of two stages: prodromal or preicteric icteric onset may be acute or insidious, with fever,malaise,anorexia,nausea,vomiting,and liver tenderness.Recovery is slow, over a periode of 4-6weeks. Very rarely a rapidly fatal fulminant hepatitis may occur. Mortality is low 0.1-1% with most of the deaths occurs in adults. HEPATITIS A VIRUS Morphology : HAV is a 27-nm,non enveloped RNA virus belongs to picornavirus family. HAV is recognised as the prototype of new genus HEPATOVIRUS. Resistance : HAV is resistant to inactivation by heat at 60'C for an hour, either and acid at pH 3,but it is inactivated by boiling for 1 minute,1:4000 formaldehyde at 37...