An adult gerbil model for evaluating potential coxsackievirus A16 vaccine candidates.

A suitable animal model of CVA16 infection is crucial in order to understand its pathogenesis and to help develop antiviral vaccines or screen therapeutic drugs. The neonatal mouse model has a short sensitivity period to CA16 infection, which is a major limitation. In this study, we demonstrate that adult (60-day-old) gerbils are susceptible to CVA16 infection at high doses (108.0 TCID50). A clinical isolate strain of CVA16 was inoculated intraperitoneally into adult gerbils, which subsequently developed significant clinical symptoms, including hind limb weakness, paralysis of one or both hind limbs, tremors, and eventual death from neurological disorders. Real-time RT-PCR revealed that viral loads in the spinal cord and brainstem were higher than those in other organs/tissues. Histopathological changes, such as neuronal degeneration, neuronal loss, and neuronophagia, were observed in the spinal cord, brainstem, and heart muscle, along with necrotizing myositis. Gerbils receiving both prime and boost immunizations of alum adjuvant inactivated vaccine exhibited no clinical signs of disease or mortality following challenge by CVA16, whereas 80% of control animals showed obvious clinical signs, including slowness, paralysis of one or both hind limbs, and eventual death, suggesting that the CVA16 vaccine can fully protect gerbils against CVA16 challenge. These results demonstrate that an adult gerbil model provides us with a useful tool for studying the pathogenesis and evaluating antiviral reagents of CVA16 infection. The development of this animal model would also be conducive to screening promising CVA16 vaccine candidates as well as further vaccination evaluation.

Vibrio cholerae O139 multiple-drug resistance mediated by Yersinia pestis pIP1202-like conjugative plasmids.

A conjugative plasmid, pMRV150, which mediated multiple-drug resistance (MDR) to at least six antibiotics, including ampicillin, streptomycin, gentamicin, tetracycline, chloramphenicol, and trimethoprim-sulfamethoxazole, was identified in a Vibrio cholerae O139 isolate from Hangzhou, eastern China, in 2004. According to partial pMRV150 DNA sequences covering 15 backbone regions, the plasmid is most similar to pIP1202, an IncA/C plasmid in an MDR Yersinia pestis isolate from a Madagascar bubonic plague patient, at an identity of 99.99% (22,180/22,183 nucleotides). pMRV150-like plasmids were found in only 7.69% (1/13) of the O139 isolates tested during the early period of the O139 epidemic in Hangzhou (1994, 1996, and 1997); then the frequency increased gradually from 60.00% (3/5) during 1998 and 1999 to 92.16% (47/51) during 2000 to 2006. Most (42/51) of the O139 isolates bearing pMRV150-like plasmids were resistant to five to six antibiotics, whereas the plasmid-negative isolates were resistant only to one to three antibiotics. In 12 plasmid-bearing O139 isolates tested, the pMRV150-like plasmids ranged from approximately 140 kb to 170 kb and remained at approximately 1 or 2 copies per cell. High (4.50 x 10(-2) and 3.08 x 10(-2)) and low (0.88 x 10(-8) to 3.29 x 10(-5)) plasmid transfer frequencies, as well as no plasmid transfer (under the detection limit), from these O139 isolates to the Escherichia coli recipient were observed. The emergence of pMRV150-like or pIP1202-like plasmids in many bacterial pathogens and nonpathogens occupying diverse niches with global geographical distribution indicates an increasing risk to public health worldwide. Careful tracking of these plasmids in the microbial ecosystem is warranted.

Preparation of armored RNA as a control for multiplex real-time reverse transcription-PCR detection of influenza virus and severe acute respiratory syndrome coronavirus.

The common respiratory viruses, including influenza A, influenza B, and newly emerging severe acute respiratory syndrome (SARS) viruses, may cause similar clinical symptoms. Therefore, differential diagnosis of these virus pathogens is frequently required for single clinical samples. In addition, there is an urgent need for noninfectious and stable RNA standards and controls for multivirus detection. In this study, reverse transcription-PCR (RT-PCR) targeting of the RNAs of influenza A and influenza B viruses and SARS coronavirus was performed, and the resulting products were spliced into a fragment which was packaged into armored RNA for use as a noninfectious, quantifiable synthetic substitute. Furthermore, in the present study we developed a multiplex real-time RT-PCR assay in which the armored RNA was used as an external positive control and the three RNA viruses could be detected simultaneously in a single reaction mix. The detection limit of the multiplex real-time PCR was 10 copies/microl of armored RNA.

[A case-crossover study on the relationship between air pollution and acute onset of cerebral hemorrhage in Hangzhou city].

OBJECTIVE: To explore the relationship between air pollution and acute onset of cerebral hemorrhage in Hangzhou. METHODS: Time-stratified case-crossover study was used to analyze the effect of aerosol optical depth (AOD), PM(10), SO(2) and NO(2) on the acute onset of cerebral hemorrhage. Conditional logistic regression was used to estimate the odds ratios (ORs) and their 95% confidence intervals (CIs) in relation to an increase of one unit of AOD and 10 microg/m(3) of air pollutants. RESULTS: After adjusted temperature and relative humidity, the ORs of acute onset of cerebral hemorrhage by a unit increase in AOD at a 2 day-lag were 1.727 (95%CI: 1.103 - 2.703) in first half year and 2.412 (95%CI: 1.230 - 4.733) at a 2 day-lag in spring. For a 10 microg/m(3) increase in SO(2), the ORs were 1.119 (95%CI: 1.019 - 1.229), 1.230 (95%CI: 1.092 - 1.386), 1.254 (95%CI: 1.076 - 1.460) in the whole year (2 day-lag), in first half year (2 day-lag) and in spring (2 day-lag), respectively. NO(2) exposure in first half year (2 day-lag) was associated with cerebral hemorrhage, with OR as 0.841 (95%CI: 0.734 - 0.964). However, there were no statistical significances for AOD, SO(2), NO(2) in the rest time-periods (P > 0.05). Additionally, no association was found between PM(10) and the acute onset of cerebral hemorrhage in any time-periods (P > 0.05). CONCLUSION: Our data showed that there was association between air pollution and the acute onset of cerebral hemorrhage, especially in spring and in the first half of the year.

[Study on the risk factors of injuries among children at school age, from the families of migrant workers in Hangzhou city].

OBJECTIVE: To explore the risk factors of injuries among school aged children from migrant workers' families, in Hangzhou. METHODS: A cross-sectional survey on 3582 students from eight separate schools in which, four were set for migrant workers' families and the other four were for families of permanent residents. Stratified cluster random sampling method was used. Data was analyzed by unconditional univariate and multivariate logistic regression methods under SPSS 13.0. RESULTS: The incidence rate of injury did not show statistical difference between children of migrant workers or from the permanent residents. The incidence rate of multiple injuries was higher in children from the migrant workers' families. The incidence rates on electric shock occurred at the primary school, drowning among boys at the secondary school and scald/crash/cutting by knives in girls at secondary schools were seen higher among children from the of migrant workers. Results from multivariate analysis showed that factors as gender (OR = 1.20), age (6 - 9 years: OR = 0.70, 10 - 12 years: OR = 1.45), fond of playing Pingpong (OR = 1.35), history of injuries by pets (OR = 1.41), skills on swimming (OR = 1.22), no history of being threatened (OR = 0.68), having harmonious family relations (OR = 0.69) and owning a house by family (OR = 0.76) appeared to be the major one that related to the occurrence of injury. CONCLUSION: Personal behavior as well as family and social environment seemed to be factors affecting the occurrence of injuries among children from the migrant workers' families.

[A case-crossover study on air pollutants and the mortality of stroke].

OBJECTIVE: To investigate the short-term effect of particulate matter in air on the mortality of stroke. METHODS: Using time-stratified case-crossover study design, an association was examined between stroke mortality and particulate matter with aerodynamic diameter of < 10 microm (PM10) of 2002 - 2004 in Hangzhou city. Meanwhile, the acute health effect of other gaseous pollutants (sulfur dioxide, SO2 and nitrogen dioxide, NO2) was also analyzed. RESULTS: A total of 9906 deaths of stroke were included. The crude stroke mortality was 83.54 per 100 000. After being adjusted for meteorological factors, when an increase of 10 microg/m3 in PM10, SO2 and NO2 in three days was noticed, it appeared that the increases of mortality of stroke were 0.56% (95% CI: 0.14%-0.99%), 1.62% (95% CI: 0.26% - 3.01%) and 2.07% (95% CI: 0.54% - 3.62%) respectively. There was no distinct association in multi-pollutant models. In sensitivity analysis, the associations were found in all single-pollutant models but not statistically significant in multi-pollutant models after replacing the missing values. CONCLUSION: It is suggested that the short-term elevation in PM10 as well as SO2 and NO2 daily concentrations were related to the increase of stroke mortality in Hangzhou city.

Laribacter hongkongensis isolated from a patient with community-acquired gastroenteritis in Hangzhou City.

We describe the isolation of Laribacter hongkongensis in Hangzhou City, People's Republic of China. One strain of bacterium, named LHHZ242, had many of the same phenotypic and genotypic characteristics as Laribacter hongkongensis described in previous publications. This discovery proves that Laribacter hongkongensis is also associated with community-acquired gastroenteritis outside Hong Kong.