HIGH PREVALENCE OF GB VIRUS-C STRAINS GENETICALLY RELATED TO STRAINS WITH ASIAN ORIGIN IN NICARAGUAN HEMOPHILIACS

The presence of hepatitis GB virus C (GBV-C), also known as hepatitis G virus (HGV), and hepatitis C virus (HCV) were investigated in sera f rom 45 hemophiliacs from nine locations in Nicaragua using a nested po lymerase chain reaction (PCR). Primers used to detect GBV-C and HCV de rived from the helicase region and 5'UTR, respectively. Seventeen (38% ) patients were positive for GBV-C RNA in serum by PCR. Twelve (27%) p atients were positive for HCV RNA by PCR. Six (13%) of these were coin fected with GBV-C. Anti-HCV was detected in all the 12 HCV RNA positiv e hemophiliacs and in another 14 (31%) individuals, in whom GBV-C RNA was found in 2. Ten patients (22%) lacked markers for both GBV-C and H CV. The mean age of the patients positive for GBV-C but negative for H CV by PCR was significantly lower than for those negative for GBV-C bu t positive for HCV by PCR (P<0.05; Student's t-test), indicating that the risk for this group of hemophiliacs to acquire GBV-C infection is higher as compared to the risk of acquiring HCV infection. Eleven GBV- C strains were sequenced in the 5'UTR. Sequence comparison to previous ly published GBV-C strains revealed that all 11 strains were more simi lar to Asian strains than to strains of European and African origin. S equences in the NS5-B region were available for 8 HCV strains, all of which were found to belong to genotype 1a. The similarity of the Nicar aguan GBV-C strains to strains from Asia indicates that the GBV-C stra ins in the region presumably have an Amerindian origin. It is also con sidered that the HTLV II strains in the New World aboriginal populatio ns are ancient and brought there by the ancestral Amerindian populatio ns from Asia. Further, the genotype F of hepatitis B virus, known to r epresent the strains in populations with Amerindian background, predom inates in Central American populations with Hispanic background. It re mains to be clarified why Ameridian strains of GBV-C as well as HBV pr edominate also in populations with mixed ethnic background in Central America. (C) Wiley-Liss, Inc.