Hepatitis D & E
What are hepatitis D and E?
Although they sit together in the hepatitis alphabet, hepatitis D and E are in fact quite different.
Hepatitis D
Hepatitis D (HDV), sometimes referred to as the delta virus or delta agent, is an incomplete virus that requires the presence of the hepatitis B virus to survive in your body. This means that it is only possible to have hepatitis D if you have hepatitis B.
You can acquire hepatitis D infection at the same time you are infected with hepatitis B. This is called ‘co-infection’. If you are infected in this way, acute hepatitis will develop following an incubation period of up to three months. This is the time it takes between infection and the appearance of first symptoms.
If you already have chronic hepatitis B and become infected with hepatitis D, this is known as ‘superinfection’. While the combination of hepatitis D and hepatitis B can be more serious than hepatitis B by itself, superinfection is more likely to cause severe chronic hepatitis and cirrhosis.
Around 5% of people with hepatitis B also have hepatitis D.
Hepatitis D is seen mainly in central Africa, the Middle East and central South America. Infection rates in most of Europe and the United States are low.
Three particular forms of the virus, called genotypes, are currently known:
- type 1, the most common form of disease in most areas of the world
- type 2, a less severe form found more commonly in Taiwan
- type 3, a more severe form found in South America.
Hepatitis D affects approximately 15 million people worldwide.
Hepatitis E
Hepatitis E (HEV) is also caused by a virus. Outbreaks have now been recorded from many areas of the world. It is most common in parts of South Asia, Africa and Central America that are associated with poor sanitation. Hepatitis E is very rare in the UK but it is now accepted that the virus is also transmitted here.
Hepatitis E has an average incubation period of four to six weeks. The disease is generally mild in its effect unless you have pre-existing liver disease and lasts only a couple of weeks. There is no chronic infection caused by hepatitis E.
It has now been classified into four genotypes:
- type 1, most commonly found in Asia and Africa
- type 2, found in Mexico
- type 3, found in USA and Europe only
- type 4, found in China, Taiwan and Japan.
In the UK, hepatitis E diagnosed in people who have travelled abroad is usually genotype 1. Overall, hepatitis E tends to affect people aged between 15 and 40 more than other groups.
Among pregnant women there is a risk of the virus causing a severe and rapidly occurring form of hepatitis that can lead to liver failure. This is called acute fulminant hepatitis and is becoming a major health concern in countries where hepatitis E more commonly occurs.
Hepatitis D, like hepatitis B and C, is called a ‘bloodborne virus’ (BBV) indicating that it is spread by blood to blood contact. This means an infected person can pass on or ‘transmit’ the virus to you if their blood is able to enter your bloodstream. This can happen through an open wound, a cut or scratch or from a contaminated needle. Even dried blood can remain infectious for more than a week.
In the UK, people who share drug injecting equipment (intravenous drug users or IDUs) are most likely to be infected by hepatitis D. Having a tattoo or body-piercing or even acupuncture can also pose a small risk if unsterile equipment is used.
The virus can be transmitted from medical and dental treatment in countries where equipment is not sterilised properly. If you have a blood disorder or require blood transfusions, you may be at risk from exposure to unscreened blood products.
There are two other main ways the virus is transmitted:
- Having penetrative sex with an infected person without wearing a condom.
- From an infected mother to her baby during birth, when the baby is exposed to the mother’s blood in the birth canal. This is called ‘perinatal transmission’.
The hepatitis E virus is spread in a way similar to hepatitis A, known as ‘faecal-oral’. This means that the virus is passed out in bowel motions (faeces) and finds its way into the mouth (orally). This can occur when you drink from a contaminated water supply or eat food that has been touched by contaminated hands.
Widespread outbreaks of the virus can occur frequently or constantly in overseas countries (referred to as ‘endemic areas’) where water supplies are contaminated with sewage after monsoons and flooding.
Unlike hepatitis B, C or D the hepatitis E virus is not transmitted through blood, needles, or other body fluids or through sexual contact.