RESUMEN
Genome sequences of chicken (low pathogenic avian influenza [LPAI] and highly pathogenic avian influenza [HPAI]) and human isolates from a 2004 outbreak of H7N3 avian influenza in Canada showed a novel insertion in the HA0 cleavage site of the human and HPAI isolate. This insertion likely occurred by recombination between the hemagglutination and matrix genes in the LPAI virus.
Asunto(s)
Brotes de Enfermedades/veterinaria , Virus de la Influenza A/genética , Gripe Aviar/epidemiología , Secuencia de Aminoácidos , Animales , Colombia Británica/epidemiología , Pollos , Humanos , Virus de la Influenza A/patogenicidad , Gripe Aviar/virología , Modelos Moleculares , Datos de Secuencia Molecular , Mutagénesis Insercional , Conformación Proteica , Alineación de Secuencia , Proteínas Virales/químicaRESUMEN
BACKGROUND: Routine HCV NAT of blood donors to detect persons in the preseroconversion phase of acute infection was introduced in Canada in October 1999. The source of virus exposure was investigated in the first, and to date only, blood donor found to be HCV NAT positive, anti-HCV negative in Canada. He was a regular donor with none of the commonly reported risk factors for HCV infection. STUDY DESIGN AND METHODS: Epidemiologic follow-up revealed that the blood donor had received antibiotics at an outpatient IV clinic 5 weeks before donation. IV solution bags and tubing for individual patients were stored in the clinic, and then the same equipment was used each time the patient returned for the next dose of antibiotics until it was replaced after every 72-hour period. Among eight other patients whose clinic visitation times overlapped was a man with chronic HCV infection. Genomic sequencing of HCV isolates from the blood donor, the patient with chronic hepatitis C, and local controls was carried out to study possible nosocomial infection. RESULTS: Genomic sequencing showed a high degree of relatedness in the hypervariable region of HCV isolates from the blood donor and putative source patient as compared with controls. Detailed molecular analysis of quasispecies of the HCV isolates further indicated that viruses from the two individuals were genetically very close to each other. CONCLUSION: The introduction of routine screening of blood donors by HCV NAT was directly responsible for the early detection and investigation of an unusual case of HCV infection involving a regular donor. Genomic sequencing studies provided firm evidence of patient-to-patient transmission of HCV in an IV clinic. The report clearly demonstrates the value of molecular fingerprinting in tracking nosocomial HCV infections.