الفهرس 
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Abstract
Viral hepatitis is caused by hepatotrophic viruses termed hepatitis A, B, C, D, E, F and G viruses. Other viruses may be cause hepatitis such as yellow fever, CMV, EBV, rubella and herpes simplex virus. All hepatitis viruses are RNA viruses except HBV which is a DNA virus. HAV is the most common hepatitis in children. It is classified into seven genotypes. HEV is leading cause of acute or short-lived hepatitis. It is classified into four genotypes. HAV and HEV are transmitted by the fecal-oral route in regions with poor hygiene standards. The immune system makes antibodies against HAV that confer immunity against future infection. The disease can be prevented by vaccination. HEV is typically a self-limiting disease with variable severity with clinical symptoms similar to those of HAV. Vaccine appears to be effective and safe against HEV. HBV is classified into eight genotypes.The infection results from exposure to infectious blood or body fluids containing blood and from vertical transmission. Most infected patient at birth or during childhood develop chronic, long-term infections. HBV vaccine can prevent infection and its serious consequences including liver cancer and cirrhosis. Transmission of HDV can occur either via superinfection or coinfection with HBV. HCV is classified into six genotypes. It is transmitted parenterally. There is currently no vaccine to prevent HCV. HAV can infect children in areas with limited hygiene and the infection increases with age. HEV infection is common in young adults aged. The infection is an important cause of morbidity and mortality in humans and is the commonest cause of hepatitis in pregnancy. Prematurity is the commonest fetal outcome. Perinatal and early childhood transmission are two major modes of HBV transmission at early age. Parenteral transmission, vertical transmission, accounts for the majority of spread of HCV. Mother to infant HCV transmission increase among women coinfected with human immunodeficiency virus (HIV). Mother to infant transmission among intravenous drug users suggest an increased risk of mother to infant HCV transmission. rates of mother to infant transmission between breast-fed and non–breast-fed infants are similar. Children are less likely than adults to clear the infection. Co-infection of HGV with HBV and with HCV has been reported. Overall incidence of HAV has decreased in recent years due to vaccination. The vaccine appeared to be effective and safe against HEV. The greatest decline has happened among children and adolescents due to routine hepatitis B vaccination. HBIg is generally administered to babies of HBV carriers. Immunization with hepatitis B vaccine protects against HDV. There are currently no vaccines for the prevention of HCV infection. The clinical picture of the infection varies from asymptomatic or subclinical infection to symptomatic with mild digestive tract symptoms, acute illness with jaundice, sever prolonged jaundice to acute fulminant hepatitis. Infections caused by HBV and HCV may be associated with a persistent carrier state and these forms of infections may progress to chronic liver disease, which may be sever. Hepatitis can be either acute or chronic. Diagnosis of viral hepatitis is done by detection of anti viral antibodies or nucleic acids in serum. Liver biopsies are important to assess the necroinflammatory activity and the grade of liver fibrosis. The direct proof of infectious agents in liver tissue is generally applied to confirm the serological diagnosis and it may be necessary in certain cases of chronic hepatitis without evidence of viral markers in blood. Hepatitis may be difficult to recognize in children because the clinical presentation often is nonspecific and mild. Determination of genotype of the virus is an important tool in assessing clinical course, disease prognosis, establishment of appropriate duration of treatment and the outcome of antiviral therapy. Moreover, genotyping is essential for epidemiological studies and tracing of the source of infection. Most HEV infections in children are minimally symptomatic and immunity is usually long lasting. The majority of HBV infections are acquired during childhood and in early adulthood in most of the Mediterranean countries. HBV can cause lifelong infection, cirrhosis of the liver, liver cancer, liver failure, and death. Children are less likely than adults to clear the infection of HBV. HDV is a defective virus that needs the HBV to exist. Egypt represents the highest prevalence of HCV all over the world. Children who had vertically acquired the infection of HCV can clear the virus spontaneously. Evaluation of hepatitis patient include assessment of risk factors for viral transmission, physical examination, clinical examination and diagnosis. Genotype is clinically important in determining geographical distribution, clinical picture, outcome of the disease and response to treatment. Screening of pregnant women for HBV to start immunization of newborn soon after birth in HBsAg positive women. PCR is recommended of blood donors for occult HBV infection.