The epidemiology and infection route of asymptomatic HCV carriers detected through blood donations.

The Japan Red Cross started screening donated blood for anti-HCV in Nov. 1989. Approximately 0.9% of donors were found to be positive by the 1st generation antibody test. The authors started a carrier clinic for the medical care of apparently healthy HCV carriers. Donors whose antibodies were strongly positive both by 1st EIA and 2nd PHA were informed, and were confirmed by RIBA 2 and RT-PCR. A total of 262 carriers (150 males and 112 females) with mean age of 46.8 +/- 11.2 yrs have visited the clinic. Of these carriers 149 were diagnosed to be asymptomatic clinically, biochemically and echographically. Eighty-seven carriers had received blood transfusions 22.7 +/- 10.9 yrs previously, while 106 had had acupuncture. Sixty had a family history of liver disease. Fifty-four had a history of heavy alcohol intake. Tattoos and/or iv drug abuse were found in 11, and nosocomial needle accidents in 4. HBV antibodies were found in 145 cases (55%). In conclusion, approximately 60% of HCV carriers found at the time of blood donation were apparently asymptomatic, suggesting the need of longer follow-up. Main routes of infection were estimated to be blood transfusion (33%), other parenteral exposure routes (6%), household (10% or less), and acupuncture (20% or less), considering duplication and priority.