Molecular Epidemiology of Hepatitis E Virus (Hev) in South America: Current Status

Abstract

Hepatitis E virus (HEV) is a common causative agent of acute hepatitis in many developing countries where standards of sanitation and hygiene are poor. HEV is transmitted primarily by the fecal-oral route. However, zoonotic trasmission from animal reservoirs to human by consumption of raw or undercooked meat has also been suggested. In endemic areas, HEV infection occurs as large waterborne epidemics and/or small outbreaks. Sporadic cases of HEV infection have also been reported in developed countries, where its occurrence is not always associated with travel to highly endemic areas. HEV mammalian isolates are classifi ed into four genotypes 1-4, which appear to have a specifi c host range and geographical distribution. The epidemiology of HEV in South America seems to be complex and seroprevalence in human and domestic pigs diff ers both among populations within the same countries and between countries. Additionally, HEV strains have been detected and molecularly characterized and genotype 3 is the most frequently genotype found in the region. Moreover, except for two strains isolated from autochthonous cases of acute hepatitis that occurred in Venezuela and belonged to genotype 1, all sequences detected in South America were classifi ed as within genotype 3. Our understanding of HEV epidemiology has undergone major changes in recent years and despite the fact that several attempts to shed light over the epidemiology of this infection have been carried out in South America, data about the molecular characterization of HEV isolates is still lacking and further investigation is needed. This review summarizes the current status of HEV molecular epidemiology from a regional point of view.

Emerging animal viruses: real threats or simple bystanders?

“…HEV was found contaminating the effluents of slaughterhouses and the virus is often found in swine manure storage facilities. The virus strains detected on swine herds and in the environmental matrices in a given geographic region are often phylogenetically related to those found in human cases of hepatitis occurred in people living nearby (Mirazo et al 2012). These findings reinforces the need of control measures to avoid the contamination of the environment, including better management practices to deal with swine manure and even the use of vaccination of swine in the future.…”

“…As mentioned before, those genotypes are restricted to humans (Mirazo et al 2012). Genotype 3 is worldwide distributed and has been causing infection in both humans and swines (Oliveira-Filho et al 2013).…”

“…Four genotypes were reported for HEV, named 1-4, based on the analysis of the complete genome sequence or partial genomic regions including a 371-nt region in ORF1 and a 147-nt region in ORF2 (Mirazo et al 2012). The genotype classification has a relationship with the host species infected and the geographical distribution of the virus (Mirazo et al 2012).…”

“…The genotype classification has a relationship with the host species infected and the geographical distribution of the virus (Mirazo et al 2012). Viruses from all 4 genotypes were found causing disease in humans, whereas only genotypes 3 and 4 are found in pigs.…”