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First
Report of Hepatitis C Virus Genotype 6 Infection in India
Researchers in India have identified, for the first
time, two patients with chronic liver disease - a 46-year-old
man and a 52-year-old woman, both from eastern India - who
were found to be infected with hepatitis
C virus genotype 6 strains. These strains have
been previously reported only from Hong Kong and Southeast
Asia.
Determining the identity of the infecting hepatitis
C virus (HCV) genotype has important implications for deciding
the duration of antiviral therapy and ascertaining prognosis
for the patient.
Of the six HCV genotypes, genotype 6 was thought to
be restricted to countries of Southeast Asia, previously having
been reported from Hong Kong and Thailand.
Case
Reports
Patient 1 was a 46-year-old man from eastern India who presented for evaluation after
a positive HCV antibody test. He provided a history of four
episodes of jaundice,
in 1981, 1982, 1992 and 2000, the first episode occurring
after having received blood transfusion. He had received injections
in vaccination camps conducted in his state.
His ALT
level at presentation was 39 U/L (64 U/L is the
upper limit of normal as estimated in healthy, volunteer blood
donors at our hospital3). Liver biopsy showed mild chronic
hepatitis with mild periportal fibrosis (modified HAI score
6/18, fibrosis score 2/6). The viral
load (Amplicor HCV Monitor , version
2.0, Roche Diagnostics, USA) was 2.4 x 105 IU per mL of plasma.
The patient was subsequently lost to follow-up.
Patient 2 was a 52-year-old woman with chronic
renal failure from eastern India who had been receiving thrice-weekly
hemodialysis sessions for 5 months prior to presentation at
our center. On routine testing she was found to be HCV antibody
positive. HCV viral load was 9 x 105 IU per mL of plasma.
ALT level was 35 U/L. The patient was followed up for three
years and ALT enzyme estimations performed eight times showed
stable levels (mean 44.5 U/L, range 30 to 54). This patient
continues to exhibit low reactivity to HCV antibody.
Both patients were negative for hepatitis B surface antigen
and antibody to HIV-1 and HIV-2.
There was no recorded history of travel outside India
in the hospital charts of both patients. The second patient
had undergone her hemodialysis sessions only in India.
Discussion
Prior identification of the infecting genotype will
help in planning the optimal duration of treatment for patients
in a cost-effective manner. Hui et. al. showed that HCV genotype
6 strains exhibit greater sustained
virological response (SVR) as compared to genotype
1 when treated with interferon.
Additionally, this study showed that a longer course
of interferon did not increase the SVR in patients with HCV
genotype 6 infection.
With increasing globalization, the geographical isolation
of certain HCV genotypes may become obsolete. Indian laboratories
and physicians must take into consideration the possibility
of encountering HCV genotype 6 strains among their patients.
Their immune response, long-term prognosis, and response to
interferon remain to be seen.
Departments
of Clinical Virology and Gastrointestinal Sciences, Christian
Medical College, Vellore, India.
Reference
S Raghuraman, P Abraham, G Sridharan, and B S Ramakrishna.
Hepatitis C virus genotype 6 infection in India. Indian
Journal of Gastroenterology 24:72-73. 2005.
Additional
Reading
Doi H, Apichartpiyakul C, Ohba KI, Mizokami M, Hotta
H. Hepatitis C virus (HCV) subtype prevalence in Chiang Mai,
Thailand, and identification of novel subtypes of HCV major
type 6. J Clin Microbiol 1996;34:569-574.
Hui CK, Yuen MF, Sablon E, On On Chan A, Chun Yu Wong
B, Lai CL. Interferon and ribavarin therapy for chronic hepatitis
C virus genotype 6: a comparison with genotype 1. J Infect
Dis 2003;187:1071-1074.
McOmish F, Yap PL, Dow BC, Follett EA, Seed C, Keller
AJ, et al . Geographical distribution of hepatitis
C virus genotypes in blood donors: an international collaborative
survey. J Clin Microbiol 1994;32:884-892.
Ohno T, Mizokami M, Wu RR, Saleh MG, Ohba KI, Orito
E, et al . New hepatitis C virus genotyping system
that allows for identification of HCV genotypes 1a, 1b, 2a,
2b, 3a, 3b, 4, 5a and 6a. J Clin Microbiol 1997;35:201-207.
06/22/05
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