in Common Diseases in Humans by

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Hepatitis A

Hepatitis B


It is also called infectious hepatitis.

It is also called serum hepatitis.


It is infectious.

It is non-infectious.


It is less dangerous.

It is more dangerous.


It never exists in human’s in chronic state.

It exists in humans in chronic state.


Causative agent: Hepatitis A virus (HAV) containing RNA.

Causative agent: Hepatitis B virus (HBV) containing DNA


Incubation period: 2–6 weeks.

Incubation period: 8–24 weeks.


Sources of Infection: Faecal matter, urine and blood serum of infected person.

Sources of Infection: Blood serum, saliva, genital secretions of infected person.


Mode of transmission: 

i. Faeco-oral route i.e. water, food, milk etc. contaminated by faeces of infected person enter through the mouth.

ii. Prolonged contact with infected person.

iii. Poor sanitation, over-crowding etc.

iv. Infected blood

v. Insect vectors


Mode of transmission:

i. Sexual contact with infected person.

ii. Bite of mosquito and bed bugs.

iii. Infected mother to her baby.

iv. Intravenous drug addicts

v. infected blood transfusion, contaminated needles, sharing razors, toothbrushes etc.

vi. Coughing, Sneezing,

vii. Vaccination

viii. Organ transplantation.


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