Epidemiology and Transmission of Hepatitis A Virus and Hepatitis E Virus Infections in the United States

Abstract

There are many similarities in the epidemiology and transmission of hepatitis A virus (HAV) and hepatitis E virus (HEV) genotype (gt)3 infections in the United States. Both viruses are enterically transmitted, although specific routes of transmission are more clearly established for HAV than for HEV: HAV is restricted to humans and primarily spread through the fecal-oral route, while HEV is zoonotic with poorly understood modes of transmission in the United States. New cases of HAV infection have decreased dramatically in the United States since infant vaccination was recommended in 1996. In recent years, however, outbreaks have occurred among an increasingly susceptible adult population. Although HEV is the most common cause of acute viral hepatitis in developing countries, it is rarely diagnosed in the United States.

The phylogenetic approach for viral infectious disease evolution and epidemiology: An updating review

“…Molecular analysis is crucial for the identification of the source of HAV infection, especially when infected cases do not declare risk factors, especially in countries with low HAV endemicity, where outbreaks are usually associated with a single HAV strain . Conversely, when outbreaks occur in highly endemic geographic areas an exposure to several HAV strains should be expected …”

“…53 Conversely, when outbreaks occur in highly endemic geographic areas an exposure to several HAV strains should be expected. [54][55][56][57][58][59][60] In recent years, numerous outbreaks of acute hepatitis A have occurred in men who have sex with men (MSM) in Europe, 61,62 United States 63 and Japan, 64 with specific HAV IIIA strains circulating among MSM communities identified by phylogenetic trees. [65][66][67][68] A large outbreak of hepatitis A has been identified in central Italy, with 523 cases identified between January 2016 and March 2017.…”

Sero-prevalence and Risk Factors for Hepatitis A Virus Infection among Pregnant Women at the Samandin Medical Center, Ouagadougou, Burkina Faso

“…The endemicity of HAV in the world differs according to geographical area as shown by the prevalence studies of anti-HAV antibodies [13][14][15]. It is estimated that most children (90%) will be infected with HAV before ten years of age in developing countries with very poor sanitary conditions and hygienic practices [12].…”

New Subgenotyping and Consensus Real-Time Reverse Transcription-PCR Assays for Hepatitis A Outbreak Surveillance

“…than in children, and in patients with underlying medical conditions, infection may lead to more severe disease such as fulminant hepatitis. Risk groups for hepatitis A infections include international travelers, men who have sex with men, and users of illicit drugs (1). While infrequent, community-based and common source outbreaks in the United States have caused significant morbidity and mortality in recent years (5,6) (https:// www.cdc.gov/hepatitis/outbreaks/2016/hav-strawberries.htm).…”

“…Comparison of strain sequences through phylogenetic analysis can provide useful information about strain relatedness as well as the possible geographic origin of strains (12). Historically, subgenotype IA has represented Ͼ80% of the HAV strains detected in the United States (1). This dynamic has changed recently with 15%, 84%, and Ͻ1% of the strains genotyped as IA, IB, and IIIA, respectively (13).…”