Hepatitis E virus is responsible for enterically-transmitted acute hepaititis in humans with two distinct epidemiological patterns. In endemic regions, large waterborne epidemics have been observed with thousands of people affected. In non-epidemic regions, sporadic cases may occur.
4 genotypes of HEV are described. Genotypes 1 and 2 are strictly human infections, genotypes 3 and 4 are found both in humans and other mammals. Infection in domestic and wild pigs is common and pig herds in NZ have a high prevalence of infection. Sporadic cases of HEV have been linked to eating meat from infected animals although in general the source of infection is uncertain.
Infection with genotype 1 or 2 usually causes a self-limiting hepatitis with low mortality except in pregnant women, in whom the mortality may reach 25% especially in the 3 rd trimester. Genotypes 3 and 4 infections are zoonotic with an apparent predilection for elderly men. Symptoms range from inapparent to acute or sub-acute liver failure, with associated neurological symptoms in a minority of patients. Despite earlier belief that HEV was always self-limiting, infection can become chronic in immunosuppressed patients.
References:
1. Garkavenko O, Obriadina D, Meng J,. et al. Detection and characterisation of Swine hepatitis E virus in New Zealand, J . Med. Virol. 65(2001), pp525-529.
2. Pavio n, Meng X-J, Renou C. Zoonotic hepatitis E: animal reservoirs and emerging risks. Vet Res (2010)41:46.
3. Matsuda H., Okada K., Takahashi K. and Mishiro S. Severe hepatitis E virus infection after ingestion of uncooked liver from a wild boar, J. Infect. Dis. 188 (2003) (6), p. 944.
4. Scobie L, Dalton HR. Hepatitis E: source and route of infection, clinical manifestations and new developments. (2013) J Viral Hepatitis. 20:1-11.
5. Narayanan Jothikumar, Theresa L. Cromeans, Betty H. Robertson, X.J. Meng and Vincent R. Hill. A broadly reactive one-step real-time RT-PCR assay for rapid and sensitive detection of hepatitis E virus ; Journal of Virological Methods. 131(2006) 1, Pages 65-71. .
For further information contact the laboratory (contact via Lablink: 22000 or (09) 307-8995 or 0800 522 7587) ,or:
the Virology team
virology@adhb.govt.nz