Five lettered viruses drive most hepatitis cases
Hepatitis means inflamed liver tissue—sometimes silent, sometimes marked by jaundice, fatigue, vomiting, and abdominal pain. The lettered viruses A through E cause most infections, though alcohol, drugs, toxins, and other microbes can also damage the organ badly.
The name joins the Greek words for liver and inflammation. Doctors call it acute if it clears within six months and chronic if it lingers longer, and chronic inflammation can scar the organ into cirrhosis, failure or cancer. Worldwide hepatitis causes more than a million deaths a year, mostly indirectly through that scarring or through liver tumours.
The five viruses travel differently. A and E spread through contaminated food and water, are commonest in developing countries and never become chronic; both should clear within one or two months. B passes mainly through sex, from mother to baby, or via infected blood, and most adult cases settle in three or four months. C usually spreads through blood, for instance shared needles, and rarely clears unaided. D can only infect someone who already carries B. Kissing or sharing cutlery does not transmit the blood-borne types unless fluids reach an open cut.
Acute viral illness tends to unfold in three stages. A flu-like prodrome of tiredness, nausea and aching joints comes first, sometimes ending with dark urine and pale stools. Jaundice follows after one or two weeks and can last up to four, often with a swollen, tender liver. Recovery comes last, though blood tests may stay abnormal. A rare catastrophic form, fulminant hepatitis, strikes 2 to 20 percent of people co-infected with B and D and 15 to 20 percent of pregnant women with E.
In 2015 about 114 million people caught hepatitis A, some 343 million lived with chronic B and about 142 million with chronic C. In the United States, fatty-liver inflammation affects around 11 million people and alcoholic hepatitis about 5 million. Vaccines protect against A, B and D, antivirals are advised for almost everyone with chronic C, and transplantation remains an option when the liver fails.
Source: Hepatitis
