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Hepatitis Virus Comparison Reference Cheat Sheet
A printable reference covering hepatitis A-E transmission, viral type, incubation, chronic infection risk, vaccines, and prevention for grades 11-12.
This cheat sheet compares hepatitis A, B, C, D, and E, the main viruses that cause liver inflammation in humans. Students need this reference because these viruses sound similar but differ in transmission, chronic disease risk, prevention, and clinical importance. A clear comparison helps connect virology, public health, vaccination, and infection control. It is designed for quick review in grade 11-12 medical science courses. The most important patterns are transmission route, genome type, incubation period, and whether infection can become chronic. HAV and HEV spread mainly by the fecal-oral route and usually cause acute disease, while HBV, HCV, and HDV spread mainly through blood or body fluids. HBV and HCV can cause chronic hepatitis, cirrhosis, and liver cancer, while HDV requires HBV to replicate. Vaccines prevent HAV and HBV, and the HBV vaccine also prevents HDV infection.
Key Facts
- HAV is a non-enveloped RNA virus that spreads mainly by the fecal-oral route and usually causes acute, self-limited hepatitis.
- HBV is an enveloped DNA virus that spreads through blood, sexual contact, and perinatal exposure, and it can cause chronic hepatitis.
- HCV is an enveloped RNA virus that spreads mainly through blood exposure and has a high risk of chronic infection.
- HDV is a defective RNA virus that requires HBV surface antigen, so HDV infection occurs only with HBV coinfection or superinfection.
- HEV is a non-enveloped RNA virus that spreads mainly by the fecal-oral route, often through contaminated water, and can be severe in pregnancy.
- Typical incubation periods are HAV 15-50 days, HBV 45-160 days, HCV 14-180 days, HDV 30-180 days, and HEV 15-60 days.
- Vaccines are available for HAV and HBV, and HBV vaccination also protects against HDV because HDV needs HBV to infect cells.
- Chronic infection risk is low for HAV and HEV, possible for HBV, high for HCV, and possible for HDV when HBV is present.
Vocabulary
- Hepatitis
- Hepatitis is inflammation of the liver that can be caused by viruses, alcohol, toxins, autoimmune disease, or other infections.
- Fecal-oral transmission
- Fecal-oral transmission occurs when viruses from contaminated stool enter the mouth through unsafe water, food, hands, or surfaces.
- Chronic infection
- A chronic infection is an infection that remains in the body for months or years and may cause long-term organ damage.
- Cirrhosis
- Cirrhosis is permanent scarring of the liver that can reduce liver function and increase the risk of liver failure.
- Coinfection
- Coinfection means a person is infected with two pathogens at the same time, such as HBV and HDV together.
- Superinfection
- Superinfection occurs when a new infection is added to an existing infection, such as HDV infecting a person who already has chronic HBV.
Common Mistakes to Avoid
- Confusing HAV with HBV is wrong because HAV spreads mainly by the fecal-oral route, while HBV spreads mainly through blood, sex, and birth exposure.
- Assuming all hepatitis viruses become chronic is wrong because HAV and most HEV infections are usually acute and do not usually persist.
- Forgetting that HDV needs HBV is wrong because HDV cannot complete its life cycle without HBV surface antigen.
- Thinking the HBV vaccine only prevents HBV is incomplete because preventing HBV also prevents HDV infection.
- Treating HCV as vaccine-preventable is wrong because there is no widely available HCV vaccine, although many HCV infections can now be cured with antiviral medicine.
Practice Questions
- 1 A patient develops acute hepatitis after drinking contaminated water during travel. Which hepatitis viruses are most likely, and what is their main transmission route?
- 2 A virus has an incubation period of about 45-160 days, spreads through blood and sexual contact, and has a vaccine. Which hepatitis virus is it?
- 3 A person with chronic HBV later becomes infected with HDV. What type of infection is this, and why can HDV infect this person?
- 4 Explain why sanitation programs and vaccination programs prevent different groups of hepatitis viruses.