Hepatitis e virus (HEV)

Hepatitis e virus (HEV) is a kind of cause human pathogens of acute viral hepatitis, belong to hepatitis a virus (Hepeviridae), for no coated spherical particles, is a kind of positive chain RNA virus. Viral genome contains three open reading frame (ORF), coding virus replication proteins, structural protein and a small protein that these proteins in the process of virus assembly and the cell play an important role. HEV has four genotypes, respectively is genotype 1, 2, 3 and 4, the genetic type 1 and type 2 mainly infect humans, and the genotype 3 and 4 can be found in the human already, can also be found in some animals.

Pathogenic characteristics

HEV RNA genome for single strand is chain, total length of about 7.2 KB, contains three parts of overlapping open reading frame (ORF). ORF1 coding virus replication of the nonstructural protein aggregation, ORF2 coding capsid protein structure and a secreted protein, ORF3 coding a small protein, these proteins in the process of virus assembly and the cell play an important role. HEV to withstand the challenge of external environment, such as changes in pH and temperature fluctuation, which makes it relatively stable in vitro, easy to spread by the fecal-oral route.

epidemic

Each year about 20 million people worldwide infected with HEV, of which about 3.3 million people can appear the symptom of hepatitis e. Prevalence of hepatitis and the regional economic development level and health conditions and distribution of HEV genotype. In health conditions is poorer and less developed economies, the popularity of HEV is more common, especially in east Asia and South Asia. China in 1986-1988 was a massive wave of hepatitis in popularity, has since there are sporadic cases report.

Route of transmission

Hepatitis is the main route of transmission dung -- the mouth the way, usually because of drinking water contaminated by feces or eating contaminated food. HEV can also be transmitted through close contact in daily life, such as sharing utensils or knives. In addition, there are reports the HEV can be spread through blood and maternal and infant way.

clinical signs and symptoms

The clinical manifestations of hepatitis is diversiform, from mild asymptomatic infection to severe acute liver failure is possible. Common clinical symptoms include jaundice, fever, fatigue, nausea, vomiting, liver area pain, etc. Symptoms in children, infection is usually asymptomatic or mild, in adults, especially women, infection can lead to severe clinical manifestations, and even liver failure.

Pathological changes

Hepatitis pathological changes similar to hepatitis, liver cells ballooning degeneration, dotted, or focal necrosis and collect abbacy inflammatory cells infiltration and other lesions. In serious cases, acute liver failure can occur, hepatic encephalopathy, and even death.

Diagnostic methods

Hepatitis diagnosis depends on the etiology of laboratory tests, including the detection of serum anti - HEV IgM and IgG antibody, and by reverse transcription polymerase chain reaction (rt-pcr) to detect HEV RNA in the blood and stool. Anti - HEV IgM test is to confirm that the key indicators of acute hepatitis, whereas rt-pcr has higher sensitivity and specificity, especially suitable for HEV prevalence of low areas.

Prevention and control measures

Hepatitis prevention rely mainly on cutting off route of transmission, including to ensure the safety of drinking water, improve health facilities, strengthen food hygiene supervision and personal hygiene. The outbreak occurs, the need of patients in isolation, and the possible contaminants disinfection treatment. At present, China has been developed and approved a hepatitis a vaccine, but has not yet spread worldwide.

conclusion

Hepatitis e is a kind of acute viral hepatitis caused by HEV, a wide range of popular and a variety of clinical manifestations. Understand its pathogenic characteristics, transmission and diagnosis methods for the prevention and control hepatitis is very important. At present, although there is no specific treatment, but by supporting treatment and appropriate preventive measures can effectively relieve symptoms and reduce transmission. With the deepening of the research on HEV, the future may have more about effective strategies for the treatment and prevention.