| Hepatitis E is a self-limited acute illness which caused by Hepatitis E virus (HEV). Acute icteric hepatitis, the commonest recognizable form of illness, is usually insidious in onset and has an initial prodromal phase lasting a week, with a variable combination of flu-like symptoms, fever, mild chills, abdominal pain, anorexia, nausea, aversion to smoking, vomiting, clay-coloured stools, darkor tea-coloured urine, diarrhoea, arthralgia, asthenia and a transient macular skin rash. In serum alanine aminotaansferasa elevate quickly to hundreds Unit. The illness may be particularly severe among pregnant women, with mortality rates reaching as high as 20%.Human healthy will be severe harmed. Hepatitis E virus (HEV) is a non-enveloped RNA (7.5 kb) virus, 27-32nm diameter particle with icosahedral symmetry. The viral genome, approximately 7.5kb in length, is a single-stranded, positive-sense, polyadenylated RNA molecule that contains short 5,and 3, non-coding regions of 27 and 68 nucleotides, respectively. It contains three overlapping open reading frames (ORF).ORF1 (5.0kb) is predicted to code for amino acid polyprotein consisting of non-structural proteins that are involved in viral genome replication and viral protein processing. ORF2 (2.0kb) encodes for the viral capsid protein. It is a major coding region of structural protains.ORF3 (369bp) is a phosphoprotein, which appears to associate with the cytoskeleton and immunocompetence of HEV.HEV gene has some difference with different areas. It retains relative stable sequence which stemmed from same regions. With HEV isolated,cloned,identified, eight genotypes of HEV were divided in world. Isolates 1 and 4 are found in China, and the major is isolate 4 in dispersed Hepatitis E.HEV, formerly, a major cause of viral hepatitis in much of the developing world, has recently been detected in swine in North America and Asia, raising concern about potential for zoonotic transmissionTo investigate if HEV is commonly present in swine in the province of Heilongjiang, pooled stool samples from swine farms were assayed by reverse transcription-polymerase chain reaction (RT-PCR) amplification. We designed 5 group primers, HEV ORF2 gene was detected by RT-PCR and was sequenced, and the results were compared with published sequences of HEV genotypes from humans and swine. HEV strains from swine in Heilongjiang has 59.6%,56.8ï¼…,59.6ï¼… and 74.4ï¼… identity to genotype I,II,III and IV in ORF2 regions. They had 57.7% identity to swine HEV from America and Japan. Our data show that HEV in swine in Heilongjiang are genetically closely related to HEV isolates from humans HEV type IV in ORF2 regions, but there were a lot of differences.In short, Characters of HEV strains from swine in Heilongjiang were examined, and ORF2 regions were cloned and sequenced, which is important to understand variation and epidemiology of hepatitis E; the same time, the study provided much useful statistics for seeking common antigenic determinants and PCR primer which could be used for making more sensitive specific diagnostic kits and vaccine for HEV.Candidate:Yu Min Major:Preventive Veterinary ScienceSupervisor:Prof. Li Jingpeng...
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