Transmission of hepatitis C virus to recipients of parenteral vitamin therapy in a primary care facility

BACKGROUND AND OBJECTIVES

The Australian prevalence of hepatitis C virus (HCV) is approximately 1%, with the majority of cases acquired through injecting drug use. However, occasionally HCV infection occurs in healthcare settings. Three new HCV infections were identified amongst patients attending a general practice in Sydney, Australia, specialising in parenteral vitamin therapy.

STUDY DESIGN

An investigation was conducted to identify the source of infection and mechanism of transmission. Molecular analysis was conducted by sequencing the HCV NS5A, Core and NS5B regions.

RESULTS

Two sources were identified using molecular epidemiology - a genotype 3a case was the source for a case acquired in late 2004 and a genotype 1b case the source for one case acquired in late 2006 and another in early 2007. The common risk factor was parenteral vitamin C therapy.

CONCLUSIONS

Inadequate infection control was apparent and likely to have resulted in blood contamination of the healthcare workers, their equipment, the clinic environment and parenteral medications. Molecular and clinical epidemiology clearly identified parenteral transmission of HCV, highlighting the risks of blood contamination of parenteral equipment and use of multi-dose flasks on more than one patient.

Detection of multiple hepatitis C virus genotypes in a cohort of injecting drug users

Multiple genotypes of the hepatitis C virus (HCV) were detected in five of 138 HCV RNA positive injecting drug users (IDUs) recruited in Melbourne, Australia. Two were detected by combined LiPA and core and NS5a region sequencing, and three more (selected for testing due to their high-risk behaviour) by heteroduplex mobility analysis. We conclude that the true prevalence of mixed infection in IDUs is undoubtedly higher than the 3.6% (five of 138) we observed, and is underestimated by LiPA, the most common method of genotyping. As responsiveness to HCV treatment varies significantly with genotype, a high prevalence of mixed HCV infections in IDUs must diminish overall treatment efficacy and lessen our ability to reduce the burden of HCV-related disease.

Evidence of patient-to-patient transmission of hepatitis C virus through contaminated intravenous anaesthetic ampoules

Two separate cases of acute hepatitis C virus (HCV) infection following medical procedures, arthroscopy and colonoscopy, are reported. In both episodes, patient risk factors were reviewed, and staff and other patients' sera were tested for HCV antibodies and RNA. HCV RNA positive samples were genotyped, sequenced, and subjected to phylogenetic analysis. No risk factors for HCV infection were identified for either case except for medical procedures. HCV RNA positive patients were identified preceding both cases on the respective theatre lists. HCV infection in a second low risk patient was also identified. Nucleic acid sequencing and phylogenetic analysis of HCV from the two putative source patients and the three recipient patients demonstrated a high degree of relatedness respectively. The results suggest that patient-to-patient transmission occurred in both episodes via contamination of intravenous anaesthetic ampoules with HCV used on multiple patients. Injectable medication ampoules should not be used for more than one patient.

Gamma-linolenic acid (GLA) is cytotoxic to 36B10 malignant rat astrocytoma cells but not to 'normal' rat astrocytes

This study compares the effect of gamma-linolenic acid (GLA) and its precursor linoleic acid (LA) on survival of 36B10 malignant rat astrocytoma cells and 'normal' rat astrocytes. GLA was cytotoxic to 36B10 cells but not to astrocytes. By contrast, LA supplementation did not affect the survival of either cell types. There were minor differences in the uptake, distribution and use of radiolabelled GLA and LA by the 36B10 cells and astrocytes. GLA and LA supplementation increased the total polyunsaturated fatty acid (PUFA) content of the cells indicating increased oxidative potential. However, elevated levels of 8-isoprostane, an indicator of increased oxidative stress, were only observed in the GLA supplemented 36B10 cells. Addition of the antioxidant trolox to GLA-enriched 36B10 cells blocked the cytotoxic effect. Further, GLA enhanced the radiation sensitivity of the astrocytoma cells but not the astrocytes; trolox blocked the GLA-mediated increase in astrocytoma cell radiosensitivity. LA did not affect the radiation response of either cell type. While cyclo-oxygenase inhibitors did not affect GLA cytotoxicity, they blocked the enhanced radiation response of GLA-supplemented cells. The lipoxygenase inhibitor NDGA did not affect the toxicity produced by GLA. Thus, GLA is toxic to the neoplastic astrocytoma cells but not to normal astrocytes.

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.

Hepatitis C virus genotypes in Australia

The relative distribution of Australian hepatitis C virus (HCV) genotypes was determined for 500 isolates. Genotyping was performed using a commercial reverse phase hybridization assay after amplification of the 5' untranslated region of HCV by the polymerase chain reaction. Australian isolates comprised, predominantly, genotype 1 (55%) and genotype 3 (38%) with genotype 2 accounting for only 7%. Genotype 3a was the most common subtype. When the major risk groups of injecting drug users or transfusion-acquired hepatitis C were compared, there was a significantly higher incidence of genotype 1b in the transfusion-acquired group (P < 0.03). When the age of the patients was analysed, genotype 3a was more prevalent in the 21-40-year age group than the 41-60-year age group (P < 0.05). There was no significant difference in genotype distribution between males and females. HCV genotypes 1, 2 and 3 are most often found in developed countries but the relatively high prevalence of genotype 3a in Australia is unusual.

Prevalence of hepatitis G virus in Queensland blood donors

OBJECTIVE

To determine the prevalence of hepatitis G virus (HGV) carriage in Queensland blood donors.

DESIGN

Cross-sectional survey with retrospective longitudinal study of HGV-positive donors.

SETTING

Brisbane Red Cross Blood Bank, 1995.

SUBJECTS

100 consecutive blood donors attending the Blood Bank on two days in October 1995 and 20 blood donors with a raised plasma alanine aminotransferase (ALT) level on their last donation.

OUTCOME MEASURES

Presence of HGV RNA by reverse transcription polymerase chain reaction (RT-PCR) in currently donated blood and in blood samples archived for up to 34 months. RT-PCR used two different reverse transcription methods and three different specific sets of primers and probes.

RESULTS

Five of the 120 blood donors were positive for HGV RNA by all RT-PCR methods (four of the 100 with normal ALT levels [4%] and one of the 20 with raised ALT levels [5%]). Retrospective testing of archived samples showed that four of these five had been persistently HGV RNA-positive for at least two years, while the fifth had been HGV RNA-negative on two donations before becoming HGV RNA-positive. No risk factors were identified for this donor.

CONCLUSIONS

A relatively large number of Queensland blood donors (4%) are persistently HGV RNA-positive.