title: Investigating an outbreak of acute viral hepatitis caused by hepatitis E virus variants in Karachi, South Pakistan.
abstract: Hepatitis E is a classic water-borne disease in developing countries. Detection of anti-HEV IgM and IgG antibodies, in addition to HEV RNA are useful epidemiological markers in diagnosis of hepatitis E. This study was conducted to investigate an outbreak of acute viral hepatitis in South-Pakistan. Anti-HEV IgM and IgG were assessed comparatively with serological kits manufactured by Abbott, Cosmic, TGH, and Wantai, selecting HEV RNA as reference assay. Molecular evolutionary analysis was performed by phylogeny and HEV spread time analysis by Bayesian Coalescent Theory approach. Of the 89 patients, 24 (26.9%) did not have acute hepatitis viral marker. Of the remaining 65 cases, 4 (6.1%) were positive for anti-HAV IgM, one (1.5%) for anti-HBc IgM, 2 (3%) for HCV, 53 (81.5%) for anti-HEV IgM, and 5 (7.7%) were hepatitis-negative. The Wantai test was 100% sensitive and specific followed by Cosmic (98.1% and 100%), TGH (98.1% and 97.2%) and Abbott (79.2% and 83.3%). Two HEV variant strains were detected by phylogeny responsible for this acute hepatitis outbreak. Estimates on demographic history of HEV showed that HEV in Pakistan has remained at a steady nonexpanding phase from around 1970 to the year 2005, in which it expanded explosively with the emergence of new HEV variants. In conclusion, the limited sensitivity of available assay (Abbott anti-HEV EIA) may be a concern in HEV diagnosis in Pakistan. This study cautions that the dissemination of the variant strains to other areas of Pakistan may lead to explosive HEV outbreaks.
authors.affiliation: Department of Virology and Liver Unit, Nagoya City University, Graduate School of Medical Sciences, Nagoya, Japan.
authors.forename: Anis
authors.initials: A
authors.lastname: Khan
authors.forename: Yasuhito
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Fuat
authors.initials: F
authors.lastname: Kurbanov
authors.forename: Abeer
authors.initials: A
authors.lastname: Elkady
authors.forename: Zaigham
authors.initials: Z
authors.lastname: Abbas
authors.forename: Zahid
authors.initials: Z
authors.lastname: Azam
authors.forename: Amna
authors.initials: A
authors.lastname: Subhan
authors.forename: Sajjad
authors.initials: S
authors.lastname: Raza
authors.forename: Sajjad
authors.initials: S
authors.lastname: Razza
authors.forename: Saeed
authors.initials: S
authors.lastname: Hamid
authors.forename: Wasim
authors.initials: W
authors.lastname: Jafri
authors.forename: James
authors.initials: J
authors.lastname: Shih
authors.forename: Ningshao
authors.initials: N
authors.lastname: Xia
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Takahashi
authors.forename: Shunji
authors.initials: S
authors.lastname: Mishiro
authors.forename: Masashi
authors.initials: M
authors.lastname: Mizokami
mesh_terms: D000293:Adolescent; D000328:Adult; D016000:Cluster Analysis; D004196:Disease Outbreaks; D005260:Female; D006508:Hepatitis Antibodies / Q000097:blood; D016751:Hepatitis E / Q000453:epidemiology*; D016752:Hepatitis E virus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010154:Pakistan / Q000453:epidemiology; D010802:Phylogeny; D011110:Polymorphism, Genetic; D012367:RNA, Viral / Q000097:blood / Q000235:genetics; D017422:Sequence Analysis, DNA; D055815:Young Adult
chemical_list: D006508:Hepatitis Antibodies; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D012367:RNA, Viral