The hepatitis C virus genotype and subtype frequency in hepatitis C virus RNA-positive, hepatitis C virus antibody-negative blood donors identified in the nucleic acid test screening program in Poland.
BACKGROUND
Since 2002, blood donors in Poland have been tested not only for hepatitis C virus antibodies (anti-HCV) but also for HCV RNA or HCV core antigen. This screening program identifies asymptomatic, recently infected individuals with no anti-HCV (in the "window period"). The aim of this study was to compare HCV genotype and subtype distribution in window-period (wp) donors, anti-HCV-positive donors, and chronic hepatitis C (CHC) patients.


METHODS
A total of 2.37 million donors were investigated for HCV RNA, and 340,000 for HCV core antigen. HCV genotypes and subtypes were investigated in 50 HCV RNA-positive, anti-HCV-negative donors; in 70 anti-HCV-positive donors; and in 170 CHC patients. Re-questioning of wp donors for probable risk factors was introduced.


RESULTS
HCV RNA was detected in 50 donors of 2.71 million (1:54,200) anti-HCV-negative blood donations. Of these 50 donors, 36 percent exhibited Subtype 1b, whereas Subtypes 3a and 4c/d were identified in 40 and 14 percent, respectively. In anti-HCV-positive donors and CHC patients, the frequency of Subtype 1b was significantly higher (75.7 and 85.3%, respectively); in both groups the lower frequency of Subtypes 3a (14.3 and 10.6%, respectively) and 4c/d (4.3 and 1.2%, respectively) was found. The probable source of infection was identified in 9 wp donors.


CONCLUSIONS
The frequency of wp donors is 18.5 per 1 million. The unexpected high frequency of Genotype 4 and Subtype 3a and the low frequency of Subtype 1b was observed in wp donors compared to anti-HCV-positive individuals. Additional epidemiologic questioning introduced after HCV RNA detection may help to identify infection source.
Brojer
E
E
Institute of Haematology and Blood Transfusion,Warsaw, Poland. ebrojer@ihit.waw.pl
Gronowska
A
A
Medyńska
J
J
Grabarczyk
P
P
Mikulska
M
M
Letowska
M
M
Kryczka
W
W
Gietka
A
A
D000293:Adolescent; D000328:Adult; D001782:Blood Donors; D005260:Female; D005838:Genotype; D016174:Hepacivirus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D018937:Hepatitis C Antibodies / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012367:RNA, Viral / Q000097:blood*
D018937:Hepatitis C Antibodies; D012367:RNA, Viral