High prevalence of GB virus C strains genetically related to strains with Asian origin in Nicaraguan hemophiliacs

Abstract

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 from 45 hemophiliacs from nine locations in Nicaragua using a nested polymerase chain reaction (PCR). Primers used to detect GBV-C and HCV derived from the helicase region and 5'UTR, respectively. Seventeen (38%) patients were positive for GBV-C RNA in serum by PCR. Twelve (27%) patients were positive for HCV RNA by PCR. Six (13%) of these were coinfected with GBV-C. Anti-HCV was detected in all the 12 HCV RNA positive 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 HCV. The mean age of the patients positive for GBV-C but negative for HCV by PCR was significantly lower than for those negative for GBV-C but 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 previously published GBV-C strains revealed that all 11 strains were more similar to Asian strains than to strains of European and African origin. Sequences 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 Nicaraguan GBV-C strains to strains from Asia indicates that the GBV-C strains in the region presumably have an Amerindian origin. It is also considered that the HTLV II strains in the New World aboriginal populations are ancient and brought there by the ancestral Amerindian populations from Asia. Further, the genotype F of hepatitis B virus, known to represent the strains in populations with Amerindian background, predominates in Central American populations with Hispanic background. It remains to be clarified why Amerindian strains of GBV-C as well as of HBV predominate also in populations with mixed ethnic background in Central America.

Frequency and genotypic distribution of GB virus C (GBV-C) among Colombian population with Hepatitis B (HBV) or Hepatitis C (HCV) infection

“…Together with other studies, our results corroborate the hypothesis that GBV-C is an old virus [21], having been probably introduced in the America continent with the fist men coming thought the Bering Strait [32-34,58]. It is generally believed that Colombian native Indians migrated from Asia to Colombia approximately 12,000 years ago and were isolated from other people for religious reasons [59].…”

“…The finding of an Asian GBV-C genotype in the Americas was first suggested by the analysis of 5'UTR hemophiliac patients from nine locations in Nicaragua [58], Colombian Amerindians [34] and Bolivia [32]. Similarity between Nicaraguan and Asian GBV-C genotype 3 strains indicates that these strains in the region presumably have an Amerindian origin [58]. …”

Structural Constraints on RNA Virus Evolution

“…Genotype 1 is confined to sub-Saharan Africa and shows the greatest overall sequence diversity (22,25); particularly divergent variants have been recovered from Pygmy and other African populations (27a, 28). These genotype distributions can potentially be mapped to the emergence and migration of modern humans out of Africa 100,000 years ago (7,28).…”

Evidence against GB virus C infection in dromedary camels

“…However, they are phylogenetically distinct from the three currently assigned genera and have recently been proposed to be members of a newly designated Pegivirus genus (Stapleton et al , 2011). Analyses of all of the GB viruses have determined that they segregate into monophyletic groups according to their host species, supporting a hypothesis for their evolutionary co-speciation with their hosts (Gonzalez-Perez,, 1997, Pavesi, 2001, Smith et al , 1997, Smith et al , 2000, Stapleton et al , 2011). …”

“…All of the GB viruses reported to date show close phylogenetic relationships with other isolates obtained from the same host species, suggesting that GB viruses co-evolve with their host species (Gonzalez-Perez,, 1997, Pavesi, 2001, Smith et al , 1997, Smith et al , 2000). Thus the report that dromedary camels have GB virus isolates that cluster within GB viruses of humans (GBV-C) was quite unexpected.…”