Hepatitis E Virus Epidemiology and Genotyping form Pakistan

Abstract

Hepatitis E virus (HEV) is an emergent source of enterically transmitted viral hepatitis and an imminent public health concern. HEV has a substantial disease burden in areas afflicted with humanitarian emergencies such as flood-affected regions, externally or internally displaced populations, and densely packed areas where access to proper sanitation and safe drinking water is challenging. Although outbreaks and sporadic cases are linked to waterborne transmission, zoonosis has also been linked to the emergence of disease. It usually presents itself as a self-resolving aliment, but chronic HEV infections prove to be devastating in immunocompromised patients and pregnant females where the infection is associated with high maternal mortality and frequent fetal loss. HEV-related clinical complications are often undetected and not considered in the differential diagnosis. Pakistan is the fifth most populous nation in the world and is faced with several challenges including recent devastating floods, sub-optimal sanitary conditions, cluster accommodation, and unregulated cross-border movements. These drastic shifts in population dynamics make these territories vulnerable to proficient disease spread. The current study thus sought to analyze the epidemiological and viral genotype characteristics of the Hepatitis E virus, to assess the genetic variants circulating in the population. Consecutive patients presenting with symptoms associated with acute liver disease were sampled from three metropolitan cities including Lahore, Peshawar, and Karachi. HEV infection was confirmed by ELISA. ELISA-positive samples (75 samples) were further subjected to viral RNA extraction, followed by the amplification of the HEV Rdrp region using Nested PCR and degenerate primers. 40% of the samples (33 samples) were found to be positive for HEV RNA indicating an active infectious state. Sequencing and phylogenetic analysis revealed that HEV isolates cluster with genotype 1. Subtype 1g was xvi found to be the prevailing subtype as compared to the previously documented subtype 1a reported from Karachi. Thus, our results indicate the presence of a newly abundant circulating subtype and thus merit a thorough investigation to further evaluate the impacts of this shift on clinical manifestation and disease severity.