Hepatitis -or inflammation of the liver- is a prehistoric disease and is considered by some to be one of the main plagues that have affected human health throughout the ages.
This infection can cause severe fatigue, nausea, vomiting, and abdominal pain, as well as jaundice (yellowing of the skin and eyes) and dark urine.
But its more serious versions cause chronic liver damage, which can lead to death.
According to the World Health Organization (WHO), more than 325 million people worldwide suffer from this condition chronically and 1.4 million die each year from this cause.
Hepatitis is the second deadliest infectious disease after tuberculosis, highlights the WHO, and there are nine times more people infected than infected with HIV.
And it is that, although one can develop the disease as a result of ingesting some toxic substances, such as alcohol and certain drugs, or due to autoimmune diseases, the most common cause of hepatitis is viruses.
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In the second half of the 20th century, scientists managed to identify a whole series of viruses that cause different forms of hepatitis.
They named these viruses after the letters of the alphabet: A, B, C, D, E, F and G.
On the occasion of World Hepatitis Day, at BBC Mundo we explain what these types of viral hepatitis are and how they differ.
There are several viruses that affect our liver, some mildly and others severely.
Hepatitis A (VHA)
This variant is caused by the hepatitis A virus (HAV) that is transmitted through contact with the fecal matter of infected people, either by not washing their hands or by consuming contaminated food or water.
According to the WHO, “most people in areas of the developing world with poor sanitation have been infected with this virus.”
It can also be spread by certain sexual practices.
But there are three reasons why HAV causes one of the least worrisome varieties of hepatitis.
On the one hand, because infections are usually mild , causing symptoms such as diarrhea, stomach pain, loss of appetite, nausea, tiredness, and fever. And only a few cases turn out to be serious and life-threatening.
On the other hand, those infected usually recover completely and acquire immunity against future infections by this virus.
And third, safe and effective vaccines to prevent this infection (usually given in the first two years of life) were developed in the 1990s.
Hepatitis B is transmitted through the blood or sexual route.
Hepatitis B (VHB)
Hepatitis B is one of the two most serious types of this disease, as it can become chronic and lead to liver failure, cirrhosis or liver cancer.
HBV is transmitted through infected body fluids, particularly blood and semen.
It can also be passed from mother to child during childbirth or from an infected family member to the baby.
Young children are at greater risk of developing chronic hepatitis B infection than those infected as adults, who, although they have severe symptoms, usually recover completely.
HBV poses a risk to healthcare personnel, who can accidentally become infected if they suffer a needle stick or wound from an item contaminated with infected blood.
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According to WHO data, almost 80% of people with chronic hepatitis were infected with HBV.
But, although there is no cure, there is good news: there are effective treatments.
And, better yet: since 1980 there is a vaccine that is capable of preventing the disease. It is recommended to administer it to newborns in the first 24 hours of life.
Hepatitis C (VHC)
This is the other more harmful and lethal variant of viral hepatitis. And it also closes the group of the three best-known varieties of hepatitis.
Scientists were only able to identify HCV in 1989 (for two decades they simply called it “non-A non-B hepatitis”)
Like HBV, it is transmitted by exposure to contaminated blood – sexual transmission is much less common, says the WHO – and the damage it causes is similar.
Most of those infected are believed to be people who shared needles with someone infected or who received blood transfusions contaminated with the virus (before 1990 donated blood was not screened for this virus).
Today it is believed that HCV causes about 20% of chronic hepatitis.
However, it has two major differences from hepatitis B.
The first is that it causes no symptoms, so the vast majority of infected people don’t find out they have the disease until decades later, when liver damage is advanced.
This surely explains why hepatitis C is the leading cause of liver transplants .
The other difference is that there is no vaccine to prevent infection.
However, there is reason to be optimistic: today 95% of chronic infections can be cured using antivirals , although treatment is expensive.
Hepatitis D (VHD)
It is linked to hepatitis B because only people who are already infected with HBV can get it from HDV.
For this reason, this virus is rare: it is estimated that 5% of patients with hepatitis B are co-infected with the hepatitis D virus, which is transmitted by the same routes (blood and semen).
However, those who contract it are at higher risk .
According to the WHO “simultaneous infection by both viruses can cause a more serious condition and have a worse outcome”.
Because of its link to HBV, the good news is that hepatitis B vaccines also protect against hepatitis D.
Hepatitis E (VHE)
Hepatitis E is transmitted in the same way as A: through ingestion of contaminated food or water, or through direct contact with infected feces.
Therefore, it is common for there to be epidemic outbreaks in underdeveloped countries, with poor sanitation systems.
However, the WHO warns that it is “increasingly recognized as a major cause of disease in developed countries .”
Like hepatitis A, it does not cause chronic liver problems, although it can be more dangerous in pregnant women.
Although there are vaccines that prevent it, they are not as widely distributed as those for hepatitis A.
For this reason, experts advise minimizing the risks by washing your hands well and avoiding consuming drinks or food (including ice) that may be contaminated.
Hepatitis F (VHF)
In 1994 several scientists discovered evidence of a virus that caused hepatitis and it was not A, B, C, D or E. They called it VHF.
It is a very rare infection, which is believed to be transmitted through contaminated food or water.
Only a few isolated cases have been documented in the world and there is very little information about this form of hepatitis.
Hepatitis G (VHG)
This virus, identified in 1996, usually only affects people already infected with hepatitis C.
But, unlike the hepatitis B and D link, being infected with HGV does not make hepatitis C worse.
Furthermore, the latest research suggests that the virus is not a pathogen, that is, it does not cause disease.