Liwen Ju

Serological and virological surveillance of avian influenza A virus H9N2 subtype in humans and poultry in Shanghai, China, between 2008 and 2010.

We report the serological evidence of low‐pathogenic avian influenza (LPAI) H9N2 infection in an occupational poultry‐exposed population and a general population. A serological survey of an occupational poultry‐exposed population and a general population was conducted using a haemagglutinin‐inhibiting (HI) assay in Shanghai, China, from January 2008 to December 2010. Evidence of higher anti‐H9 antibodies was found in serum samples collected from poultry workers. During this period, 239 H9N2 avian influenza viruses (AIVs) were isolated from 9297 tracheal and cloacal paired specimens collected from the poultry in live poultry markets. In addition, a total of 733 influenza viruses were isolated from 1569 nasal and throat swabs collected from patients with influenza‐like symptoms in a sentinel hospital, which include H3N2, H1N1, pandemic H1N1 and B, but no H9N2 virus was detected. These findings highlight the need for long‐term surveillance of avian influenza viruses in occupational poultry‐exposed workers.

The epidemiology of hospitalized influenza in children, a two year population-based study in the People's Republic of China.

BackgroundThe epidemiology and disease burden of annual influenza in children in mainland Peoples Republic of China have not been reported in detail. To understand the incidence and epidemiology of laboratory-proven influenza hospitalization in children in China, a review of available laboratory and hospital admission data was undertaken.MethodsWe conducted a retrospective population-based study in Suzhou and the surrounding area of Jiangsu province, China for hospitalized cases of respiratory illness at Suzhou Childrens Hospital. Cases of pneumonia or respiratory illness were identified from hospital computer data bases. Routine virological testing by fluorescent monoclonal antibody assay of all hospitalized children identified influenza and other viruses. We calculated incidence rates using census population denominators.ResultsOf 7,789 specimens obtained during 2007 and 2008, 85 were positive for influenza A and 25 for influenza B. There were 282 specimens with parainfluenza virus and 1392 with RSV. Influenza occurred throughout the year, with peaks in the winter, and in August/September. Overall estimated annual incidence of laboratory-proven influenza hospitalization was 23-27/100,000 children 0-4 years old, and 60/100,000 in infants 0-6 months, with an average hospitalization of 9 days.ConclusionsInfluenza disease in young children in this part of China is a relatively common cause of hospitalization, and occurs throughout the year. The use of influenza vaccine in Chinese children has the potential to reduce the effect of influenza in the children, as well as in their communities. Studies are needed to further assess the burden of influenza, and to develop and refine effective strategies of immunization of young children in China.

Co-infection with influenza A/H1N1 and A/H3N2 viruses in a patient with influenza-like illness during the winter/spring of 2008 in Shanghai, China

Co‐infection with different influenza viruses occurs naturally and plays an important role in epidemiology and pathogenicity. To monitor the prevalence of influenza viruses in humans during seasonal influenza epidemics in Shanghai, China, and to analyze the genetic characteristics of the viruses, 365 nasopharyngeal swabs collected from patients with influenza‐like illness between January and April 2008, were tested by a colloidal gold assay, viral isolation in Madin‐Darby canine kidney (MDCK) cells, direct immunofluorescence assay and multiplex RT‐PCR. The genetic characteristics of the viruses were analyzed by full‐length PCR amplification of the HA segment. One case of co‐infection with influenza A/H1N1 and A/H3N2 viruses was detected among the 7 cases of A/H1N1, 84 cases of A/H3N2 and 48 cases of influenza B virus during the winter/spring of 2008. All influenza A/H1N1 and A/H3N2 isolates were similar, including the co‐infecting isolates. The present study demonstrates the possibility of natural co‐infection with different types of influenza viruses in humans, which could provide the opportunity for the occurrence of viral genetic reassortment within the human respiratory tract. J. Med. Virol. 82:1299–1305, 2010.

Antigenic and genetic variation in the hemagglutinins of H1N1 and H3N2 human influenza a viruses in the Shanghai area from 2005 to 2008.

Continued rapid evolution of the influenza A virus is responsible for annual epidemics and occasional pandemics in the Shanghai area. In the present study, the representative strains of A/H1N1 and A/H3N2 influenza viruses isolated in the Shanghai area from 2005 to 2008 were antigenically and genetically characterized. The antigenic cartography method was carried out to visualize the hemagglutination‐inhibition data. Antigenic differences were detected between circulating A/H1N1 strains isolated from 2005 to 2006 and the epidemic A/H1N1 strains isolated in 2008, which were found to be associated with the amino acid substitution K140E in HA1. The present vaccine strain A/Brisbane/59/2007 is considered to be capable of providing sufficient immunity against most of the circulating A/H1N1 viruses isolated in 2008 from the Shanghai population. The study showed that there were significant antigenic differences between the epidemic A/H3N2 strains isolated in 2007 and 2008, suggesting that antigenic drift had occurred in the A/H3N2 strains isolated in 2008. The P194L mutation was thought to be responsible for the antigenic evolution of influenza A/H3N2 viruses isolated from Shanghai in 2008. Evidence of antigenic drift suggests that the influenza A/H3N2 vaccine component needs to be updated. J. Med. Virol. 83:1113–1120, 2011.

Biological Characteristics of H9N2 Avian Influenza Viruses from Healthy Chickens in Shanghai, China

Background H9N2 avian influenza viruses that circulate in domestic poultry in eastern China pose challenges to human health. However, few studies have compared the biological characteristics of H9N2 viruses isolated from healthy chickens in Shanghai. Material/Methods Three H9N2 viruses – CK/SH/Y1/07, CK/SH/Y1/02, and CK/SH/23/13 – isolated from healthy chickens in Shanghai between 2002 and 2013, were selected and their biological characteristics were determined. Results All 3 H9N2 viruses showed a preference for both the avian- and human-like receptors, and they replicated well in MDCK and A549 cells. All H9N2 viruses were non-pathogenic to mini-pigs and were detected in the trachea and lung tissues. The CK/SH/Y1/07 and CK/SH/Y1/02 viruses were transmitted to mini-pigs through direct-contact or respiratory droplet exposure, but CK/SH/23/13 virus was not. Conclusions These results suggest that H9N2 viruses isolated from healthy chickens in Shanghai efficiently replicate and transmit among pigs and other mammals.

Serologic study on the outbreak of acute upper respiratory tract infections caused by adenovirus 3

From April to June, 2004, an outbreak of acute upper respiratory tract infections (AURTI) occurred in the north area of Jiangsu Province, China. Twenty throat swabs were collected with 13 of them presenting an adenovirus (Ad)-like cytopathogenic effect on HEp-2. These were verified as Ad by the electron microscope, direct immunofluorescence assay and Ad primer-mediated PCR. Moreover, they were identified as adenovirus type 3 (Ad3) by type-specific PCR and sequencing of the amplification products. Subsequent serologic studies were carried out to finally diagnose and document the outbreak. The neutralization test of paired serum of six in nine cases show obviously increased antibodies titers. The positive rate of IgM, IgG and recovery phase neutralization antibodies of the cases were 3.7%, 44.4% and 59.5% respectively while those of the controls were 0%, 8.3% and 33.3% respectively. The P values of Chi-Square were 0.510, 0.018 and 0.226 respectively. The concordance between IgG detected by ELISA and neutralization anti bodies detected by the neutralization test was 61.4% and the P value of Kappa was 0.070. By the serologic study, we can definitively diagnose that this outbreak of acute respiratory infections was caused by Adenovirus 3.