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Following the notification of nine hepatitis A cases partly clustered near an oyster growing area in the Côtes d’Armor district (Brittany, France), epidemiological, environmental and microbiological investigations were performed in order to identify the source and vehicle of contamination and devise control measures. The investigations identified 111 cases, all of whom lived or had stayed in the district. Of these cases, 87% had eaten raw bivalve molluscs and 81% had specifically eaten oysters. The raw molluscs originated from a single shellfish farm located at the north of Paimpol bay. The shellfish were probably contaminated while being stored in submersible tanks or purified in a land-based tank. They were tainted either by sewage overflows or releases from a polluted storm sewer or effluents from on-site sanitation facilities. To prevent future food-borne outbreaks due to shellfish consumption, hazards should be analysed for each farm of this area. Sewage collecting and treatment facilities should be up-graded around the bay and timely information on sewage overflows should be provided.

In patients with chronic hepatitis C, determination of hepatitis C virus (HCV) genotype could be routinely run in the future to tailor treatment schedules. The suitabilities of two versions of a serological, so-called serotyping assay (Murex HCV Serotyping Assay version 1-3 [SA1-3] and Murex HCV Serotyping Assay version 1-6 [SA1-6]; Murex Diagnostics Ltd.), based on the detection of genotype-specific antibodies directed to epitopes encoded by the NS4 region of the genome, for the routine determination of HCV genotypes were studied. The results were compared with those of a molecular biology-based genotyping method (HCV Line Probe Assay [INNO-LiPA HCV]; Innogenetics S.A.), based on hybridization of PCR products onto genotype-specific probes designed in the 5' noncoding region of the genome, obtained with pretreatment serum samples from 88 patients with chronic hepatitis C eligible for interferon therapy. Definitive genotyping was performed by sequence analysis of three regions of the viral genome in all samples with discrepant typing results found among at least two of the three assays studied. In all instances, sequence analysis confirmed the result of the INNO-LiPA HCV test. The sensitivity of SA1-3 was 75% relative to the results obtained by the genotyping assay. The results were concordant with those of genotyping for 92% of the samples typeable by SA1-3. The sensitivity of SA1-6 was 89% relative to the results obtained by the genotyping assay. The results were concordant with those of genotyping for 94% of the samples typeable by SA1-6. Overall, SA1-6 had increased sensitivity relative to SA1-3 but remained less sensitive than the genotyping assay on the basis of PCR amplification of HCV RNA. Cross-reactivities between different HCV genotypes could be responsible for the mistyping of 8 (SA1-3) and 6% (SA1-6) of the samples. Subtyping of 1a and 1b is still not possible with the existing peptides, but discriminating between subtypes may not be necessary for routine use.

Although clotting factor concentrates prepared from large pools of plasma are considered to be safe for enveloped viruses (HIV, HBV and HCV), these products are likely to remain at risk for non lipid enveloped viruses. The prevalence of positive IgG serology for human parvovirus B19 (HPV-B19) was determined in 53 children suffering from haemophilia A, who had been treated from birth with only one brand of a highly purified factor VIII concentrate prepared by ion exchange chromatography with a solvent-detergent step (HPSD-VIII). HPV-B19 seropositivity ranged from 20 to 43% in 198 age matched controls. In contrast, the incidence of positive HPV-B19 IgG serology varied from 75 to 100% in haemophiliacs and all 10 severe haemophilia A patients under 3 years of age were seropositive. The presence of HPV-B19 in this clotting factor concentrate demonstrates that at least a proportion of such products continue to transmit non lipid enveloped viruses.

UNLABELLED This study aimed at describing the evolution of the epidemiological pattern of hepatitis A in New Caledonia since 1986 and the recent epidemic which occurred in 2005-2006, regarding particularly its demographic and virological aspects and the public health response implemented. The annual or monthly activity records for Hepatitis A sero-diagnostic performed at the Pasteur Institute of New Caledonia were processed in a retrospective analysis (9723 samples tested for the detection of IgM to hepatitis A). Over the 2004-2006 period, a phylogenetic study of representative strains from New Caledonia and other Pacific islands was carried out by the French National Reference Laboratory for hepatitis A (Paul-Brousse hospital, Villejuif, France). RESULTS The continuous improvement of hygiene that occurred in New Caledonia during the last two decades led to a dramatic drop in the frequency of hepatitis A among patients tested, ranging from an average value of 79 cases (14%) for the 1986-1999 period to 0 case from 2002. However, in 2005, a strong increasing number of confirmed cases was notified, mainly among young people (78% were under the age of 20). In 2006, this epidemic reached the island of Futuna where it involved more than 1% of the total population (56 cases). The phylogenetic study has confirmed the clonality of the virus circulating during this epidemic, not related to other regional strains (Fiji, Vanuatu, New Zealand) nor with a New Caledonian strain from the previous endemic period. This transition situation, with persistence of a high epidemic risk, should encourage the health authorities to implement adapted response strategies, based in particular on systematic case declaration and targeted immunisation programmes.