Chinese Medical Information Portal Website (Taiwan Medical Network-TMN) - OldDoc Wu's Series
(Established in March 1996)
Dr. Wu's Liver diseases
for professionals (medical students and residents)
(Posted Sep. 16, 1996; Updated May 14, 2009)
Viral hepatitis A
(Key words: viral hepatitis A, hepatitis)
- Hepatitis A is a liver disease caused by a virus called the hepatitis A virus.
- The hepatitis A virus is passed in the stool of the infected person, therefore you could get the hepatits A by eating or drinking contaminated food or water.
- You might be able to get hepatitis A by kissing an infected person or having anal sex with an infected person.
- When you get hepatitis A, you may feel like you have the flu (tired, fever, sick to your stomach), pass dark yellow urine, and have yellowish eyes and skin. It is not unfrequent that some people don't have any symptoms.
- Most people who have hepatitis A get well on their own after a few weeks. However, you need to rest in bed for several days or weeks, and never drink alcohol until you are well.
- You may prevent yourself from getting the hepatits A by having the hepatitis A vaccine given through a shot.
- FAQ about information on hepatitis A (CDC).
- For more information, refer to the followings in the "for professional "section.
- Hepatitis A virus is a RNA virus, 27nm enterovirus
- HAV virus is shed in stool during the period from 7 ~ 10 days prior to one week after the onset of the illness, therefore it is not easy to
prevent the infection from HAV.
- Keeping food and dining utensils clean and uncontaminated for prevention of Infection from HAV.
- Clinical symptoms usually subside 2 ~ 6 weeks after the onset of symptoms and natural cure occurs in 4~8 weeks.
- 1~2 % of the cases will come out to be fulminant hepatitis and
die within 2 weeks.
- HAV superinfection on patient with chronic hepatitis C or B may develop into fulminant hepatitis. (NEJM, 1998; 338:286).
- In recent studies, the age incidence of HAV has shown a tendency of more cases and more severe clinical course and outcome among older persons and cases with extrahepatic complications of acute renal failure, pure red cell anemia, hypoplastic anemia, hemolytic anemia and idiopathic thrombocytopenic purpura.
- Severe clinical conditions may be caused by variant strains through cytopathic effect (Beneduce F, et al. 1995; Virus Res 36: 299-309).
- Recently, homosexuality of men and HIV victims are included in high risk group of HAV infection. (Ishida T. et al.; Jpn.J.Infect.Dis. 1999; 52: 131-132. MMWR; 1998; Vol 47, No 34;708)
- Successful control of HAV infection in Taiwan
- Infection rate in western plain region of Taiwan:
- 1981: above the age of 15 yrs ----- 95% of the people have
- 1989: 15 yrs old -----33%, 13 yrs old ----- 15% of the population
have been infected.
- It means that there has been a remarkable improvement in environmental sanitation in western Taiwan since after 1981.
- On the contrary, the infection rate in eastern mountain region
- 1991: above 15 yrs old -----95 ~ 100%
- 7 ~ 14 yrs old ----- 85 ~ 90%
- 1 ~ 6 yrs old ----- 75%
- Thus, we can evaluate the status of the environmental sanitation of a region by the infection rate of viral hepatitis A .
- Most of the population in western plain region, who were born before 1966, have already been infected with HAV and having antibody to HAV, therefore, they will not be reinfected from HAV.
- However, those born after 1980, having grown under the well controlled environmental sanitation and never infected by HAV, are susceptible to infection by HAV because they have no antibody to HAV.
- Those born between 1967 to 1979 are having antibody to HAV in different proportion, the lower in those born later.
- Therefore, most of the population group born after 1980 in the western region of
Taiwan are susceptible to hepatitis A virus infection and should
receive vaccination against hepatitis A virus before traveling
to high endemic regions as those countries of South-Eastern Asia
and mainland China, including the eastern mountain region of Taiwan.
- In Japan, only below 1% of the population born after 1954 have been infected from HAV in the survey by Kiyohara in 1994, therefore they are all susceptible to HAV infection. The situation is the same in all developed countrues.
- In war time or the natural disaster causing poor environmental
sanitation, there will be a high possibility of epidemics of viral
- For reference:
- For more information refer to:
Table 1: Age-specific prevalence of antibodies to HAV among residents
in two regions with different socioeconomic status in Taiwan
|Age group ||Western plain region || Eastern and central mountain regions
| || %(+ve/No) || %(+ve/No)|
|< 6 months ||75.0 ( 3/4 ) ||85.7 ( 6/7 )|
|> 6 months ||11.8 ( 2/17 ) ||22.2 ( 4/18 )
| 1 year || 0.0 ( 0/15 ) ||30.4 ( 17/56 )|
| 2 || 0.0 ( 0/15 ) ||32.1 ( 27/84 )|
| 3 || 5.0 ( 1/20 ) ||39.5 ( 47/122)|
| 4 || 0.0 ( 0/12 ) ||43.7 ( 59/135)|
| 5 || 0.0 ( 0/17 ) ||62.9 (102/163)|
| 6 || 0.0 ( 0/127) ||81.0 (145/179)|
| 7 || 1.5 ( 2/132) ||84.4 (184/218)|
| 8 || 2.2 ( 3/136) ||90.5 (266/294)|
| 9 || 3.4 ( 5/145) ||90.2 (212/235)|
| 10 || 6.3 ( 9/142) ||90.0 (288/317)|
| 11 || 6.1 (10/164) ||92.7 (254/274)|
| 12 || 6.0 ( 9/151) ||97.0 (192/198)|
|13 ||14.7 (21/143) ||96.0 (121/126)|
|14 ||31.8 (42/132) ||92.3 (119/129)|
| 15 ||32.8 (43/131) ||98.7 ( 77/129)|
|16 ||43.2 (43/100) ||93.1 ( 27/29 )
|Total ||11.9 (188/1581) ||81.0 (2137/2637)|
( Wu, J.-S.; J Formosan Med Assoc, 1993;92:812-5)
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(By Jau-Shin Wu, M.D.; Posted Sep. 16, 1996; Revised May 12, 2009)
(TMN) Since June 09, 2002
(Dr. Wu's Liver D) Since Jan. 01, 2008
(Olddoc)Since Jan. 01, 2008
(TMN) Since Jan. 01, 2008