Experimental infection of chimpanzees with hepatitis G virus and genetic analysis of the virus

Hepatitis G virus (HGV) was transmitted to 2 chimpanzees by inoculation with human plasma containing approximately 10(8) genome equivalents (GE) of HGV. The infection was characterized by the late appearance (weeks 10 and 11 after inoculation [pi]) of viremia that persisted throughout the 120-week follow-up. Serum HGV titer increased steadily until it plateaued at 10(6)-10(7) GE/mL. However, despite this relatively high titer, neither of the chimpanzees developed hepatitis. The sequence of the viral genome, recovered from each chimpanzee at week 77 pi, differed from that of the inoculum by 5 nt (2 aa) and 27 nt (2 aa). Two more chimpanzees were inoculated with a first-passage plasma pool. The chimpanzee inoculated with approximately 10(6.7) GE of HGV had viremia at week 1 pi. However, the viral titer increased with the same kinetics as observed in the first passage. The second chimpanzee inoculated with approximately 10(4.7) GE of HGV had late appearance (week 7 pi) of viremia.

Hepatitis G virus and fulminant hepatic failure: evidence for transfusion-related infection

BACKGROUND/AIMS

In the majority of cases of fulminant "viral" hepatitis in Australia, no known aetiological agent can be isolated. We have examined the possible role of the recently discovered hepatitis G virus (HGV) in such cases.

METHODS

An HGV specific reverse transcription polymerase chain reaction (RT-PCR) was performed on pre- and post-liver transplant serum from 14 patients who were referred for transplantation at our unit between 1989 and 1995 for unexplained fulminant hepatic failure. Eleven patients successfully underwent transplantation and three died while waiting for a suitable donor organ. Hepatitis viruses A-E were excluded by standard serological and PCR based testing. HGV RT-PCR was also performed on 21 other, randomly selected, liver transplant recipients ("controls").

RESULTS

The 14 fulminant cases were HGV RT-PCR negative prior to transplantation while five of 21 controls were positive. Post-transplant, eight of the 11 fulminant patients were found to be HGV RT-PCR positive and the same five controls remained HGV RT-PCR positive. In three of the eight fulminant patients the HGV infection resolved.

CONCLUSIONS

Our data indicate that HGV infection is unlikely to be responsible for fulminant hepatitis and that it is probably acquired from blood and/or blood products during the transplantation process. Furthermore, long-term carriage of HGV post-transplant is not associated with clinically apparent liver disease.

Short report: evidence of worldwide transmission of hepatitis G virus

Hepatitis G virus (HGV) has been recently documented in the Americas, Europe, and Australia. Distinct risk populations from North Africa, South America, and Southeast Asia were screened for HGV, in addition to hepatitis B and C viruses. First time recognition of HGV is described from Egypt and Indonesia. Notable is the high proportion of HGV positive individuals among multiply transfused children, ranging from 24% of those sampled from Egypt to 32% in Indonesia. Also, data from Peru suggest the likely association of HGV infection with progressive liver disease. Hepatitis G virus should be considered a world-wide health concern.

The incidence of transfusion-associated hepatitis G virus infection and its relation to liver disease

BACKGROUND

The role of hepatitis G virus (HGV) in transfusion-associated infection and its relation to liver disease are not well understood.

METHODS

Serum samples collected between 1972 and 1995 from 357 transfusion recipients, 157 controls who did not receive transfusions, 500 randomly selected volunteer blood donors, and 230 donors of blood received by HGV-infected patients were tested for HGV RNA by qualitative and quantitative polymerase-chain-reaction assays. Samples obtained before transfusion and serially after transfusion from 79 of the 81 transfusion recipients who had transfusion-associated non-A, non-B hepatitis were available for testing.

RESULTS

Of the 79 patients with transfusion-associated hepatitis, 63 (80 percent) had infections related to the hepatitis C virus (HCV) and 3 had preexisting HCV and the cause of their acute hepatitis could not be determined; of the remaining 13 patients, 3 had acute HGV infection, and 10 were infected with unidentified agents. Six of the 63 patients with HCV infection who were tested (10 percent) were also infected with HGV. The three patients infected only with HGV had mild hepatitis (mean peak alanine aminotransferase level, 198 U per liter; none had jaundice); the levels of alanine aminotransferase and HGV RNA were not well correlated. The combined HCV and HGV infections were no more severe than HCV infections alone; the alanine aminotransferase values paralleled the levels of HCV RNA, but not those of HGV RNA. There were 35 HGV infections among the 357 transfusion recipients; only 3 had hepatitis with HGV as the sole viral marker. One of the 157 controls and 7 of the 500 randomly selected blood donors (1.4 percent) had detectable HGV RNA. In all eight instances in which a transfusion recipient had acute HGV infection after transfusion and samples from all donors could be tested, at least one HGV-positive donor was identified.

CONCLUSIONS

HGV was common in a group of volunteer blood donors, and it can be transmitted by transfusion. Most HGV infections were not associated with hepatitis. HGV did not worsen the course of concurrent HCV infection. No causal relation between HGV and hepatitis has been established.

Hepatitis G virus infection: clinical characteristics and response to interferon

A new member of the Flaviviridae family has recently been cloned and completely sequenced. The new virus, tentatively named hepatitis G virus (HGV) and known to be closely related to GB virus C (GBV-C), is transmitted by blood and blood products, intravenous drug use and other behaviour associated with a high risk of parenteral exposure to blood. The association of the virus with hepatitis is demonstrated by the presence of raised liver transaminase (alanine aminotransferase, ALT) levels in patients infected with HGV in the absence of other identifiable causes of hepatitis. No patient sera from groups exposed to blood and blood products were found to be positive when tested for the presence of GBV-A or GBV-B sequences, two other recently described flaviviruses. Forty-five per cent of the HGV-infected patients investigated had normal ALT suggesting the existence of a normal carrier state. Persistent infection of up to 13 years duration was observed. Co-infection with hepatitis B or hepatitis C viruses (HBV and HCV) was commonly seen presumably because of shared risk factors. None of five patients with fulminant hepatic failure was positive for HGV infection. The virus is sensitive to interferon-alpha, but sustained responses were not seen with the treatment regimens used for HBV and HCV. Viral titres increased during immunosuppression following liver transplantation and the higher levels of viraemia were in one case accompanied by elavated ALT. Whether HGV (GBV-C) replicates in the liver in some or all cases remains to be established. Preliminary data suggest that it is present within peripheral blood lymphocytes.

Prevalence and disease association of hepatitis G virus infection in Japan

A reverse transcriptase-polymerase chain reaction procedure (RT-PCR) for the detection of hepatitis G virus (HGV) RNA was used to examine the prevalence of HGV infection and HGV-related disease in Japan. Among 48 patients with acute non-A, B, C, D, E (non-A-E) hepatitis (five transfusion-associated cases and 43 sporadic cases), only one patient (2%), a transfusion recipient, was HGV RNA positive. Similarly, among 50 patients with established chronic non-A-E hepatitis, only two (4%) were positive for HGV RNA. These frequencies were not significantly different from those in 129 voluntary blood donors (0.8%). By contrast, HGV infection was relatively common among patients who were also infected with other hepatitis viruses. HGV co-infection or superinfection was found in seven of 53 (13%) patients with acute hepatitis C, in 15 of 126 (12%) patients with chronic hepatitis C, in three of 21 (14%) patients with acute hepatitis B and in four of 81 (5%) patients with chronic hepatitis B. Among the 29 dually infected patients, 15 (52%) had a history of blood transfusion. HGV was also detected in seven (10%) of 69 haemodialysis patients, of whom only one had a dual infection with hepatitis C virus (HCV) and an elevated aminotransferase level.

IN CONCLUSION

HGV RNA was found in only a low percentage of patients with either acute or chronic non-A-E hepatitis: HGV appears to co-infect or superinfect in 10-15% of HCV infections and in 5-15% of HBV infections; the prevalence of HGV infection (0.8%) among voluntary blood donors in Japan is similar to that for HCV infection; a history of blood transfusion was obtained in 22 (55%) of the total 40 HGV-positive subjects; and isolated HGV infection appears to have a low disease burden.

Molecular cloning and disease association of hepatitis G virus: a transfusion-transmissible agent

An RNA virus, designated hepatitis G virus (HGV), was identified from the plasma of a patient with chronic hepatitis. Extension from an immunoreactive complementary DNA clone yielded the entire genome (9392 nucleotides) encoding a polyprotein of 2873 amino acids. The virus is closely related to GB virus C (GBV-C) and distantly related to hepatitis C virus, GBV-A, and GBV-B. HGV was associated with acute and chronic hepatitis. Persistent viremia was detected for up to 9 years in patients with hepatitis. The virus is transfusion-transmissible. It has a global distribution and is present within the volunteer blood donor population in the United States.

Diagnosis of symptomatic visceral leishmaniasis by use of the polymerase chain reaction on patient blood

To diagnose symptomatic visceral leishmaniasis (kala-azar) using peripheral blood rather than tissue aspirates, a polymerase chain reaction (PCR) technique was developed for which the detection limit is 1 Leishmania-infected macrophage in 8 mL of blood. For Indian, Kenyan, or Brazilian patients with parasitologically confirmed kala-azar, 57 of 63 cases before treatment had blood that was PCR-positive (90% sensitivity). None of 40 clinically healthy persons had PCR-positive blood (100% specificity). Twelve (92%) of 13 clinically cured Indian patients had negative PCR reactions 1-6 months after treatment. This PCR procedure can provide a parasitologic diagnosis for the vast majority of kala-azar cases before therapy, may identify patients who have been successfully treated by chemotherapy, and should substantially reduce the need for invasive tests.

Transfusion-associated human immunodeficiency virus type 1 from screened antibody-negative blood donors

Cases of human immunodeficiency virus type 1 (HIV-1) infection acquired from transfusion of screened antibody-negative blood have been reported since 1986. Recent reports have proposed new combination antibody assays or the addition of HIV-1 p24 antigen testing to enhance the screening of blood donations further. Since antibody testing for HIV-1 began in 1985, 700,000 donor units have been screened at US Army blood donor centers. The US Army blood donor/recipient "lookback" program recently identified two cases of HIV-1 infection that resulted from a screened negative donation. Samples from the implicated unit, as well as from previous donations from the same donor, were available for testing to assess the performance of current screening methods. Sequential donation samples were assayed by five different Food and Drug Administration-approved HIV-1 screening enzyme-linked immunosorbent assays, a Food and Drug Administration-approved Western blot, a recombinant envelope-based enzyme-linked immunosorbent assay, a p24 antigen capture assay, a radioimmunoprecipitation assay, and a polymerase chain reaction. The HIV-1 p24 antigen and genomic RNA material were detected in a donation that was screened as negative by four of the five Food and Drug Administration-licensed screening enzyme-linked immunosorbent assays. Two recipients of transfusion products from this donation became infected with HIV-1. A sample from a prior donation from this donor was negative for HIV-1 by all assays. The status of blood donors who are in the early stages of HIV-1 infection may not be detected by current screening methods. While this is a rare phenomenon, it highlights the need for technologic developments in screening methods to narrow the time between infection and detection. In addition, it emphasizes the need for more effective education and counseling to enhance the utility of self=deferral.