Section 3 Viral Hepatitis

Introduction of Viral Hepatitis

Viral hepatitis including hepatitis A,B,C,D and E,is a sort of infectious disease caused by a wide variety of hepatitis viruses manifesting inflammation and necrosis in liver,which was incorporated into the B class infectious disease. Viral hepatitis has symptoms such as acute fever,poor appetite,nausea,discomfort in abdomen,and jaundice several days later in some sufferers. There are many kinds of hepatitis different from each other in etiology,epidemiology,immunology and pathogenesis,requiring different measures to prevent and control.

Viral hepatitis falls into two types in terms of transmission routes:fecal-oral route that includes hepatitis A and hepatitis E;body fluid-skin(mucosa)route spreading virus via mother-baby,sexual behavior and medical procedures that includes hepatitis B,hepatitis C and hepatitis D. Hepatitis A and E do not have carriers or develop chronic hepatitis,while hepatitis B,C and D are prone to produce carriers,chronic hepatitis,cirrhosis and liver cancer.

Hepatitis A has an incubation period of 15-45 days,and 30 days on average. The spreading phase is two weeks around onset of the disease. Hepatitis A has an incubation period of 10-70 days,and 40 days on average. Although spreading phase of hepatitis E is ambiguous,hepatitis E virus is detectable in feces of patients at late stage of the incubation period and two weeks after onset. Compared with hepatitis A,hepatitis E has more severe cases and a higher mortality rate particularly for pregnant women as high as 20%. Immunity to hepatitis E is not enduring. Adult patients are common for hepatitis E. Hepatitis B has an incubation period of 30-180 days,and 70 days on average. Hepatitis C has an incubation period 15-150 days and 50 days on average. Incubation period for hepatitis D is ambiguous,which may equivalent to incubation period of hepatitis B.

To control hepatitis that are transmitted via fecal-oral route,cut off way allowing viruses to enter mouth;to prevent hepatitis that spread via body fluidskin(mucosa),block the viruses from entering skin. In addition,vaccinate people susceptible to hepatitis A and hepatitis B.

1. Diagnostic criteria

(1)Symptoms and signs:

recent obvious malaise,digestive symptoms,swollen liver with tenderness or percussion pain,jaundice(or not) in sclera or skin persisting for at least one week,which are unexplainable by other causes.

(2)Hepatitis function exams:

ALT significantly increases,increment(or not) of serum bilirubin,after exclusion of other causes to liver damage such as drugs or alcohol.

2. Pathogen typing diagnosis

(1)Hepatitis A

1) Evidences for clinical diagnosis of viral hepatitis.

2) Testing of HAV markers:HAV-IgM or HAVIgG increases 4 times in double serum specimens.

3) Epidemiology data:intake history of dirt food/beverage within 45 days before onset or history of close contact to patients with acute hepatitis A.

Item 1) and 2) are indispensable prerequisites for diagnosis of sporadic cases of hepatitis A,and the epidemiology data are for reference.

To confirm an outbreak case of hepatitis A,evidences described by the first item are indispensable;and to diagnose debut patient or earlystage patient,4-time-increase of HAV-IgM and HAV-IgG in double serum specimens are necessary. Those sharing common suspect foods or water with the debut patient,being in the longest incubation period of hepatitis A,having hepatitis symptoms unexplainable by other causes,with or without 4-time-increase of HAV-IgM and HAV-IgG in double serum specimens,can be diagnosed as patient of hepatitis A.

(2)Hepatitis B

1) Evidences for clinical diagnosis of viral hepatitis.

2) Testing of HBV markers:(a) Positive serum HBsAg(solo positive or compound positive,such as HBsAg,HBeAg,anti-HBc simultaneously positive,HBsAg,anti-HBe,anti-HBc simultaneously positive,HBsAg and anti-HBc simultaneously positive,etc.);(b) Positive serum HBV-DNA or positive PCR test for HBV-DNA;(c) Positive HBcAg or positive HBsAg or positive HBV- DNA in liver tissue.

Any positive results of the above helps to confirm present case of hepatitis B.

3) Epidemiology data:history of receiving blood or blood products or medical procedures in recent half year;history of close contact to hepatitis B patient,particularly those sexual contacts without condom use.

With evidences described by item 1) and 2) but without history of hepatitis B can be diagnosed as new case of hepatitis B;with history of hepatitis B or suffering from hepatitis B longer than a half year can be diagnosed as chronic hepatitis B. Epidemiology data are for reference.

(3)Hepatitis C

1) Evidences for clinical diagnosis of viral hepatitis.

2) Testing of HCV markers:(a) Positive serum HCV-RNA;(b) Positive serum anti-HCV IgM.

Any positive results of the above can be diagnosed as present case of hepatitis C.

3) Epidemiology data:history of receiving blood or blood products or medical procedures in recent half year.

With evidences described by item 1) and 2) but without history of hepatitis C can be diagnosed as new case of hepatitis C;with history of hepatitis C or suffering from hepatitis C longer than a half year can be diagnosed as chronic hepatitis C. Epidemiology data are for reference.

(4)Hepatitis D

1) Evidences for clinical diagnosis of viral hepatitis.

2) Testing of HDV markers:(a) Positive serum HDVAg;(b) Positive serum HDV-RNA;(c) Positive anti-HDV IgM.

Any positive results of the above can be diagnosed as present case of hepatitis D.

3) Testing of HBV markers:(a) Positive serum HBsAg(solo positive or compound positive,such as HBsAg,HBeAg,anti-HBc simultaneously positive,HBsAg,anti-HBe,anti-HBc simultaneously positive,HBsAg and anti-HBc simultaneously positive,etc.);(b) Positive serum HBV-DNA or positive PCR test for HBV-DNA;(c) Positive HBcAg or positive HBsAg or positive HBV- DNA in liver tissue.

4) Epidemiology data:the same as hepatitis B.

With evidences described by item 1),2) and 3)but without history of hepatitis D can be diagnosed as new case of hepatitis D;with history of hepatitis D or suffering from hepatitis D longer than a half year can be diagnosed as chronic hepatitis D. Epidemiology data are for reference.

(5)Hepatitis E

1) Evidences for clinical diagnosis of viral hepatitis.

2) Testing of HEV markers:positive anti-HEV IgM,or four-time-increment of anti-HEV IgG in double serum specimens.

3) Epidemiology:history of contact to hepatitis patient or drank feces/garbage contaminated water,or have meals in non-home settings,or history of visiting HEV ravaged areas.

Item 1) and 2) are necessary for diagnosing sporadic cases of hepatitis E,and epidemiology data are for reference.

To confirm an outbreak case of hepatitis E,evidences described by the first item are indispensable;and to diagnose debut patient or early-stage patient,4-time-increase of HEV-IgM and HEV-IgG in double serum specimens are necessary. Those sharing common suspect foods or water with the debut patient,being in the longest incubation period of hepatitis E,having hepatitis symptoms unexplainable by other causes,with or without 4-time-increase of HEV-IgM and HEV-IgG in double serum specimens,can be diagnosed as patient of hepatitis E.

(6)Undifferentiated viral hepatitis

With evidences for clinical diagnosis of viral hepatitis,but without procedures for testing hepatitis markers or inability to determine the type of hepatitis.

(7)Hepatitis virus carriers

Definition:people who have infected hepatitis virus longer than 6 months but void of clinical symptoms or signs of hepatitis,and hepatitis function tests give normal results. They are called hepatitis B,C or D carriers according to virus they carry. The carriers include the infected that have never take on symptoms or signs as well as post-onset virus carriers.

In real practices it is difficult to determine time that a virus carrier acquires the virus,all people that are positive for hepatitis markers test but without hepatitis symptoms or signs and with normal hepatitis function tests are regarded as carriers for hepatitis virus.

经粪-口途径传播的病毒性肝炎流行病学个案调查表

Epidemiological Questionnaire for Cases of Viral Hepatitis Transmitted via Stool/Mouse

Questionnaire

经体液-皮肤(黏膜)传播的病毒性肝炎流行病学个案调查表

Epidemiological Questionnaire for Cases of Viral Hepatitis Transmitted via Body Fluids/Skin(Mucous Membrane)

(本章编者-陈纯 本章核对-马蒙蒙 孙艺)