Hepatitis E is caused by an infection with the hepatitis E virus (HEV). The virus is a single-stranded RNA virus belonging to the Hepeviridae family and it is not coated. The human HEV Orthohepevirus A can be divided into four genotypes. For genotype 3 (HEV-3), which is common in Germany, and genotype 4 (HEV-4), which is common in Asia, domestic boar and wild boar are the main hosts. Humans are the only known reservoir for genotypes 1 (HEV-1) and 2 (HEV-2), both of which are common in Asian and African regions. The rising number of reported cases in recent years can be attributed to increased medical interest, as hepatitis E is increasingly being acquired worldwide as a zoonosis (a disease that can be transmitted from animals to humans and vice versa) rather than a disease acquired through travel.
In industrialised countries, the main risk of infection is through consumption of undercooked pork and game. It can also be transmitted through blood. A smear infection is also possible with HEV-1 and HEV-2. Especially in developing countries, this form of hepatitis E virus can spread through water or food where hygienic conditions are poor.
Compared to the estimated 20 million people worldwide who carry the virus, the number of deaths remains consistently low. One reason is that asymptomatic infections with HEV-3 primarily occur. Symptomatic infections mostly heal without consequences after mild gastrointestinal symptoms (icterus, discoloured urine, fever, fatigue or loss of appetite). During this period, the disease is contagious for one week before and four weeks after the onset of the first signs of illness. Apart from these symptoms, atypical symptoms such as peripheral neuralgia or meningitis can occur. After an incubation period of 15 to 64 days, immunosuppressed people and pregnant women may also develop a more serious chronic form of the disease. Pregnant women who contract HEV-1 represent an additional risk group. The maternal mortality rate in the third trimester is 30 percent. No maternal deaths have been reported for infections during pregnancy with HEV-3, which is widespread in Europe.
As there is low risk of transmission of hepatitis E by direct contact, infection can be avoided in outpatient areas through basic hand hygiene. In inpatient areas, basic hygiene measures must be adhered to; in addition, wearing gloves and protective gowns is recommended. The patient should be isolated and use separate sanitary facilities. In Germany, Switzerland and Austria, hepatitis E must be reported. Immunosuppressed patients should be monitored continuously to prevent liver damage. If the patient has previously donated blood, the respective institutions must be informed immediately.
The hepatitis E virus can survive for months outside a host body. This considerably increases the probability of transmission to humans through food and water.
The required spectrum of activity against the hepatitis E virus is: virucidal.