GB Virus C

High Prevalence of GBV-C in Volunteer Blood Donors in South Africa

A high prevalence of GBV-C hepatitis infection was found in South African blood donors.

“The implications of the high prevalence of GBV-C RNA in the blood donor population in this South African study are uncertain. If GBV-C is shown to play a role in disease, the findings in this study may have important implications for future screening of volunteer blood donor populations, and may affect adversely the available blood supply,” wrote Alison Casteling, University of Witwatersrand, South Africa, and colleagues (“GB Virus C Prevalence in Blood Donors and High Risk Groups for Parenterally Transmitted Agents from Gauteng, South Africa,” Journal of Medical Virology, 1998;55:103-108).

Both GB virus C (Simons et al., Nature, 1995;1:564-569) and Hepatitis G virus (Linnen et al., Science, 1996;271:505-508) are single-stranded RNA viruses thought to be isolates of the same virus (Zuckerman, Lancet, 1996;347:558-559). In the current report, Casteling et al. refer to this virus as GB virus C (GBV-C).

Little information is available about the epidemiology, mode(s) of transmission, and pathology associated with GBV-C, and reports have been conflicting, Casteling et al. noted.

“This is the first report from South Africa that describes the prevalence and epidemiology of GBV-C infection in this country using RT-PCR [reverse-transcriptase polymerase chain reaction] techniques to detect GBV-RNA in blood donors and groups at high risk for parenteral exposure,” Casteling et al. wrote.

The researchers studied the prevalence of GBV-C infection in voluntary blood donors and in groups at high risk for parenteral exposure to infectious agents. The high risk groups included chronic renal failure on hemodialysis, renal transplant patients, and hemophiliacs from the Johannesburg General Hospital in Gauteng, South Africa. The blood specimens from the blood donors were obtained from the South African Blood Transfusion Service in Gauteng.

Of the blood donors, 11.1 percent were positive for GBV-C, compared to 23.8 percent of hemodialysis patients, 23.5 percent of hemophiliacs, and 41.2 percent of the renal transplant patients.

Casteling et al. also measured serological markers for Hepatitis B virus (HBV) and Hepatitis C virus (HCV) as indicators of other hepatitis viruses with important parenteral transmission routes.

Of the GBV-C positive blood donors, 3.6 percent also were HBsAg positive and none were HCV positive. The GBV-C positive patients on hemodialysis were not positive for HBsAg or antibodies to HCV, however, they showed evidence of past infection with HBV, because 40 percent were anti-HBc positive. The greatest proportion of HCV positive individuals, 91.3 percent, was found in the group of hemophiliacs; none were HBsAg positive, but 39.1 percent had anti-HBc. In the GBV-C renal transplant patients, 4 percent had HBsAg, 13.3 percent had anti-HBc, and 2.1 percent had antibodies to HCV, the researchers reported.

Finding such a high prevalence (11.1 percent) of GBV-C in blood donors in Gauteng was noteworthy, Casteling et al. said. The figure is considerably higher than figures reported for other areas of the world, except for West Africa at 14.2 percent (Dawson et al., Journal of Medical Virology, 1996;50:97-103) and 12.9 percent in paid blood donors in the United States (Dawson et al., 1996). The next highest reported figure is 4.7 percent in Germany (Herringlake et al., Lancet, 1996;348:1626-1629).

This research was funded by grant number 96/7 from the Poliomyelitis Research Foundation.

The corresponding author for this study is Alison Casteling, National Institute for Virology, Private Bag X4, Sandringham, 2131, South Africa.

– by Cathy Clark