Full-length genome of wild-type hepatitis A virus (DL3) isolated in China. (33/226)

AIM: To characterize the genome of an wild-type HAV isolate (DL3) in China. METHODS: A stool specimen was collected from hepatitis A patient from Dalian, China. HAV (DL3) was isolated and viral RNA was extracted. The genome of DL3 was amplified by reverse transcription and polymerase chain reaction (RT-PCR), followed by cloning into pGEM-T vector. The positive colonies were selected and sequenced. The full-length genome of DL3 was analyzed and compared with other wild-type HAV isolates. RESULTS: The genome of DL3 was 7 476 nucleotides (nt) in size, containing 732-nt 5'untranslated region (UTR), 6 681-nt open reading frame (ORF) which encoded a polyprotein of 2 227 amino acids (aa), and 63-nt 3'UTR. The base composition was 28.96 % A (2 165), 16.08 % C (1 202), 22.11 % G(1 653) and 32.85% U (2 456). Genomic comparisons with wild-type HAV isolates revealed that DL3 had the highest identity of 97.5 % for nt (185 differences) with AH1, the lowest identity of 85.7 % (1 066 differences) with SLF88. The highest identity of 99.2 % for amino acid (18 differences) appeared among DL3, AH2 and FH3, and the lowest identity of 96.8 % (72 differences) between DL3 and SLF88. Based upon comparisons of the VP1/2A junction and the VP1 amino terminus, DL3 was classified as subgenotype IA. Phylogenetic analysis showed that DL3 was closest to the isolates in Japan. CONCLUSION: The sequence comparison and phylogenetic analysis revealed that DL3 is most similar to the isolates in Japan, suggesting the epidemiological link of hepatitis A happened in China and Japan.  (+info)

Virus-contaminated oysters: a three-month monitoring of oysters imported to Switzerland. (34/226)

Molluscan shellfish are known to be carriers of viral and bacterial pathogens. The consumption of raw oysters has been repeatedly linked to outbreaks of viral gastroenteritis and hepatitis A. Switzerland imports over 300 tons of oysters per year, 95% of which originate in France. To assess the level of viral contamination, a 3-month monitoring study was conducted. Therefore, the sensitivities of several previously described methods for virus concentration were compared, and one protocol was finally chosen by using dissected digestive tissues. Eighty-seven samples consisting of five oysters each were analyzed for Norwalk-like viruses (NLVs), enteroviruses, and hepatitis A viruses from November 2001 to February 2002. The oysters were exported by 31 French, three Dutch, and two Irish suppliers. Eight oyster samples from six French suppliers were positive for NLVs, and four samples from four French suppliers were positive for enteroviruses; two of the latter samples were positive for both viral agents. No hepatitis A viruses were detected. The sequences of NLV and enterovirus amplicons showed a great variety of strains, especially for the NLVs (strains similar to Bristol, Hawaii, Mexico, and Melksham agent). The data obtained indicated that imported oysters might be a source of NLV infection in Switzerland. However, further studies are needed to determine the quantitative significance of the risk factor within the overall epidemiology of NLVs.  (+info)

Outbreak of hepatitis A among men who have sex with men: implications for hepatitis A vaccination strategies. (35/226)

Between November 1998 and May 1999, 136 cases of hepatitis A were reported in Columbus, Ohio. Eighty-nine (65%) case patients were reinterviewed. Of 74 male case patients, 47 (66%) were men who have sex with men (MSM). These 47 MSM were compared with 88 MSM control subjects, to identify risk factors for infection and potential opportunities for vaccination. During the exposure period, 6 (13%) case patients reported contact with a person who had hepatitis A, compared with 2 (2%) control subjects (odds ratio, 6.15; 95% confidence interval, 1.04-48.02); neither number of sex partners nor any sex practice was associated with illness. Most case patients and control subjects (68% and 77%, respectively) saw a health care provider at least annually, and 93% of control subjects reported a willingness to receive hepatitis A vaccine. MSM are accessible and amenable to vaccination; increased efforts are needed to provide vaccination, regardless of reported sex practices.  (+info)

Safety and immunogenicity of hepatitis A vaccine in human immunodeficiency virus-infected patients: a double-blind, randomized, placebo-controlled trial. (36/226)

The safety and immunogenicity of inactivated hepatitis A (HepA) vaccine was assessed in 133 hepatitis A virus-seronegative, human immunodeficiency virus (HIV)-infected adults. Patients were randomly assigned to receive, in a blinded fashion, either 2 doses of vaccine (1440 enzyme-linked immunosorbent assay units) or placebo 6 months apart. Seroconversion at month 9 was observed in 68% of those with CD4 cell counts >/=200 cells/mm(3) but in only 9% of those with lower CD4 cell counts (P=.004). HepA vaccine was well tolerated and had no effect on the course of HIV infection or plasma HIV RNA load.  (+info)

Signals in hepatitis A virus P3 region proteins recognized by the ubiquitin-mediated proteolytic system. (37/226)

The hepatitis A virus 3C protease and 3D RNA polymerase are present in low concentrations in infected cells. The 3C protease was previously shown to be rapidly degraded by the ubiquitin/26S proteasome system and we present evidence here that the 3D polymerase is also subject to ubiquitination-mediated proteolysis. Our results show that the sequence (32)LGVKDDWLLV(41) in the 3C protease serves as a protein destruction signal recognized by the ubiquitin-protein ligase E3alpha and that the destruction signal for the RNA polymerase does not require the carboxyl-terminal 137 amino acids. Both the viral 3ABCD polyprotein and the 3CD diprotein were also found to be substrates for ubiquitin-mediated proteolysis. Attempts to determine if the 3C protease or the 3D polymerase destruction signals trigger the ubiquitination and degradation of these precursors yielded evidence suggesting, but not unequivocally proving, that the recognition of the 3D polymerase by the ubiquitin system is responsible.  (+info)

Homogeneous hepatitis A virus particles. Proteolytic release of the assembly signal 2A from procapsids by factor Xa. (38/226)

Among the picornaviridae, hepatitis A virus (HAV) is unique in that its assembly is driven by domain 2A of P1-2A, the precursor of the structural proteins (Probst, C., Jecht, M., and Gauss-Muller, V. (1999) J. Biol. Chem. 274, 4527-4531). Whereas infected individuals excrete in stool mature HAV capsids with VP1 as the major structural protein, its C-terminal extended form VP1-2A is the main component of immature procapsids produced in HAV-infected cells in culture. Obviously, a postassembly proteolytic step is required to remove the primary assembly signal 2A from VP1-2A of procapsids. Mutants of VP1-2A were expressed in COS7 cells to determine the cleavage site in VP1-2A and to test for the cleavage potential of viral and host proteinases (factor Xa and thrombin). Site-specific in vitro cleavage by factor Xa and thrombin occurred in procapsids that contained VP1-2A with engineered cognate cleavage sites for these proteinases. Interestingly, factor Xa but not thrombin liberated mature VP1 also from native procapsids in an assembly-dependent manner. The data show that domain 2A, which is required for pentamerization of its precursor polypeptides and thus for the primary step of HAV assembly, is removed from the surface of immature procapsid by a host proteinase. Moreover, our data open a novel avenue to produce homogeneous HAV particles from recombinant intermediates by in vitro treatment with exogenously added proteases such as factor Xa or thrombin.  (+info)

A multiplex reverse transcription-PCR method for detection of human enteric viruses in groundwater. (39/226)

Untreated groundwater is responsible for about half of the waterborne disease outbreaks in the United States. Human enteric viruses are thought to be leading etiological agents of many of these outbreaks, but there is relatively little information on the types and levels of viruses found in groundwater. To address this problem, monthly samples from 29 groundwater sites were analyzed for 1 year for enteroviruses, hepatitis A virus, Norwalk virus, reoviruses, and rotaviruses by multiplex reverse transcription-PCR (RT-PCR). A procedure with which to remove environmental RT-PCR inhibitors from groundwater samples was developed. The procedure allowed an average of 71 liters of the original groundwater to be assayed per RT-PCR, with an average virus recovery rate of 74%, based on seeded samples. Human enteric viruses were detected in 16% of the groundwater samples analyzed, with reoviruses being the most frequently detected virus group.  (+info)

Foodborne transmission of hepatitis A--Massachusetts, 2001. (40/226)

Hepatitis A virus (HAV) is transmitted typically from person to person by the fecal-oral route. Foodborne transmission occurs when an HAV-infected food handler contaminates food during preparation or when food is contaminated during harvesting or processing before reaching the food service establishment or home. Postexposure prophylaxis (PEP) with immune globulin (IG) can prevent hepatitis A among exposed persons if administered within 14 days of exposure. However, the decision about whether to implement PEP for persons who eat food prepared by an infected food handler depends on an assessment of the duties performed by the food handler and personal hygiene while potentially infectious, which are often difficult to determine. This report summarizes the investigation of an outbreak of foodborne hepatitis A in Massachusetts in which a food handler with hepatitis A, who was considered unlikely to transmit HAV, was implicated as the source. The findings underscore challenges faced by local and state health departments when determining whether PEP is appropriate.  (+info)