A highly pathogenic avian influenza virus, H5N1, caused disease outbreaks in poultry in China and seven other east Asian countries between late 2003 and early 2004; the same virus was fatal to humans in Thailand and Vietnam. Here we demonstrate a series of genetic reassortment events traceable to the precursor of the H5N1 viruses that caused the initial… (More)
To determine whether avian H5N1 influenza viruses associated with human infections in Vietnam had transmitted to pigs, we investigated serologic evidence of exposure to H5N1 influenza virus in Vietnamese pigs in 2004. Of the 3,175 pig sera tested, 8 (0.25%) were positive for avian H5N1 influenza viruses isolated in 2004 by virus neutralization assay and… (More)
Tissue tropism and pathogenesis of influenza A virus subtype H5N1 disease in humans is not well defined. In mammalian experimental models, H5N1 influenza is a disseminated disease. However, limited previous data from human autopsies have not shown evidence of virus dissemination beyond the lung. We investigated a patient with fatal H5N1 influenza. Viral RNA… (More)
Dengue viruses (DV), composed of four distinct serotypes (DV1 to DV4), cause 50 to 100 million infections annually. Durable homotypic immunity follows infection but may predispose to severe subsequent heterotypic infections, a risk conferred in part by the immune response itself. Antibody-dependent enhancement (ADE), a process best described in vitro, is… (More)
The pathogenesis of avian influenza A (H5N1) virus in humans has not been clearly elucidated. Apoptosis may also play an important role. We studied autopsy specimens from 2 patients who died of infection with this virus. Apoptosis was observed in alveolar epithelial cells, which is the major target cell type for the viral replication. Numerous apoptotic… (More)
In Thai provinces where avian influenza outbreaks in poultry had been confirmed in the preceding 6 months, serum from 322 poultry farmers was tested for antibodies to avian influenza virus subtype H5N1 by microneutralization assay. No study participant met the World Health Organization serologic criteria for confirmed infection.
BACKGROUND Individuals infected with the 2009 pandemic virus A(H1N1) developed serological response which can be measured by hemagglutination-inhibition (HI) and microneutralization (microNT) assays. METHODOLOGY/PRINCIPAL FINDINGS MicroNT and HI assays for specific antibody to the 2009 pandemic virus were conducted in serum samples collected at the end of… (More)
BACKGROUND Nasopharyngeal aspirate (NPA), nasal swab (NS), and throat swab (TS) are common specimens used for diagnosis of respiratory virus infections based on the detection of viral genomes, viral antigens and viral isolation. However, there is no documented data regarding the type of specimen that yields the best result of viral detection. In this study,… (More)