Xinxin Shen

Human rabies surveillance and control in China, 2005–2012

BackgroundRabies reemerged in China during the 1990s with a gradual increase in the number and geographical dispersion of cases. As a consequence, a national surveillance program was introduced in 2005 to investigate the outbreak in terms of vaccination coverage, PEP treatment, and geographical and social composition.MethodsThe surveillance program was coordinated at the national level by the Chinese Center for Disease Control (CCDC) with data collected by regional health centres and provincial CCDCs, and from other official sources. Various statistical and multivariate analysis techniques were then used to evaluate the role and significance of implemented policies and strategies related to rabies prevention and control over this period.ResultsFrom 2005–2012, 19,221 cases were reported across 30 provinces, but these primarily occurred in rural areas of southern and eastern China, and were predominantly associated with farmers, students and preschool children. In particular, detailed analysis of fatalities reported from 2010 to 2011 shows they were associated with very low rates of post exposure treatment compared to the cases with standard PEP. Nevertheless, regulation of post-exposure prophylaxis quality, together with improved management and vaccination of domesticated animals, has improved prevention and control of rabies.ConclusionsThe various control policies implemented by the government has played a key role in reducing rabies incidences in China. However, level of PEP treatment varies according to sex, age, degree and site of exposure, as well as the source of infection. Regulation of PEP quality together with improved management and vaccination of domesticated animals have also helped to improve prevention and control of rabies.

Making rabies prophylaxis more economical: immunogenicity and safety results from a preliminary study using a 2-1 intramuscular regimen in healthy volunteers.

Background: Rabies is fatal in nearly 100% of cases, making post-exposure prophylaxis (PEP) a required measure for preventing mortality. Currently, the rabies vaccination regimen requires at least three to five clinic visits, with vaccination and transportation costs being very high. This study assessed the safety and efficacy of the 2-1 intramuscular (IM) regimen for rabies immunization with the goal of making rabies prophylaxis more economical. Methods: One-hundred and eighty-one subjects were divided into two groups: 79 subjects in test group A and 102 subjects in control group B. 2-1 IM regimen was chosen for group A and the Essen regimen was adopted for group B. Serum samples were also collected at D0, D7, D14, D45, D180, and D360 to determine the rabies serum neutralizing antibody by rapid luorescent focus inhibition test (RFFIT). Results: There was no significant difference between groups A and B with respect to the rate of adverse events following each vaccination. Nine-hundred and nineteen blood samples were obtained. At D0 (prior to immunization), all study subjects exhibited a geometric mean titer (GMT) <0.05 IU/ml. On D14, all study subjects exhibited NAb titers >0.5 IU/ml; titers above 0.5 IU/ml were maintained in both groups through D45 and D180 before gradually declining. The percentage of subjects positive for NAbs in group A and group B on D7 were 88.6% and 87.3%, respectively, which was not statistically different (P = 0.545). On D360, the percentage of subjects positive for NAbs in group A and group B were 93.9% and 100% (P < 0.01), respectively. During the study, the GMT was highest for both groups on D14 (21.90 IU/ml, group A; 19.93 IU/ml, group B) (P = 0.045). On D45, the GMTs were 8.28 IU/ml (group A) and 7.89 IU/ml (group B) (P = 0.037). On D7, D180, and D360, there were no statistically significant differences between the two groups with respect to the GMT. Conclusions: The 2-1 IM regimen demonstrates the same safety and efficacy as the Essen regimen. The use of the 2-1 IM regimen could not only reduce the personal economic burdens of rabies immunization but also improve rabies immunization rates through fewer office visits and compliance with immunization procedures. However, further evaluation is needed before a major recommendation can be made.

Molecular Epidemiology of Reemergent Rabies in Yunnan Province, Southwestern China

This province is a focal point for spread of rabies between Southeast Asia and China.

Rabies Cases in the West of China Have Two Distinct Origins

In China, rabies remains an ongoing threat to public health. Although control efforts have been effective in reducing the number of annual cases, the virus continues to spread into new areas. Tibet, Qinghai, Gansu and Ningxia in western China have, until recently, reported only a handful of events. However, since 2011, there have been increasing numbers of cases recorded in these areas. In this study, we report the collection and analysis of samples collected from these regions. We find that cases originate from two different sources. Strains collected from Gansu and Ningxia are closely related to the primary lineage associated with the current epizootic, whereas those from Tibet and Qinghai are related to the Arctic-like-2 lineage that is most commonly associated with wildlife cases in China. Thus, it appears that while the epizootic is beginning to encroach into Gansu and Ningxia, Tibet and Qinghai a significant number of rabies cases originate from wildlife.

Establishment and preliminary application of a rapid fluorescent focus inhibition test (RFFIT) for rabies virus

The World Health Organization (WHO) standard assay for determining levels of the rabies virus neutralization antibody (RVNA) is the rapid fluorescent focus inhibition test (RFFIT), which is used to evaluate the immunity effect after vaccination against rabies. For RFFIT, CVS-11 was used as the challenge virus, BSR cells as the adapted cells, and WHO rabies immunoglobulin (WHO STD) as the reference serum in this study. With reference to WHO and Pasteur RFFIT procedures, a micro-RFFIT procedure adapted to our laboratory was produced, and its specificity and reproducibility were tested. We tested levels of RVNA in human serum samples after immunization with different human rabies vaccines (domestic purified Vero cell rabies vaccine (PVRV) and imported purified chick embryo cell vaccine (PCECV)) using different regimens (Zagreb regimen and Essen regimen). We analyzed the levels of RVNA, and compared the immune efficacy of domestic PVRV and imported PCECV using different immunization regimens. The results showed that the immune efficacy of domestic PVRV using the Zagreb regimen was as good as that of the imported PCECV, but virus antibodies were generated more rapidly with the Zagreb regimen than with the Essen regimen. The RFFIT procedure established in our laboratory will enhance the comprehensive detection ability of institutions involved in rabies surveillance in China.

Factors influencing the number of rabies cases in children in China.

To understand the epidemic situation and factors influencing rabies cases in children in China, we obtained an overview of the current epidemic based on individual data of rabies cases in children and a descriptive analysis was carried on the prevalence and related factors. The results showed that the rabies cases in children accounted for 21.3% of the total number of rabies cases in China, 97.0% of these cases occurred in rural areas, they were mainly caused by dogs (81.5%), and were primarily level III exposure (47.7%). More than half of the cases were not treated with wound care, vaccination rate was extremely low (15.7%), and only 5.9% of cases were injected with antibodies. Furthermore, 25.4% of cases adopted incorrect treatments such as extruding bleed and wound closure, cases vaccinated with 5 injections accounted for only 22.5%. In conclusion, the prevalence of rabies cases in children in China remains a serious concern, the number and immune status of dogs in rural areas, and knowledge of rabies by risk populations should be considered in future rabies prevention and control programs.

Molecular Characteristics and Phylogenetic Analysis of N Gene of Human Derived Rabies Virus

OBJECTIVE To investigate the relationship between the molecular characteristics and phylogenetic evolution of rabies N gene. METHODS Saliva samples were collected from rabies cases, and RT-PCR was used to amplify the N gene of rabies virus with the specific primers. The amplifying product of RT-PCR was cloned to pUCm-T vector and transformed into E.coli XL1-Blue and then the blue-white selection, PCR screening and gene sequencing were carried out to identify the positive clones. Finally, ExPASy and other bioinformatics software were used to analyze and predict the structure and biological characteristics of the N genome. RESULTS The amplification product of RT-PCR was 1 353 bp, the recombinant plasmid pUCm-T/N was constructed, the whole length of the N gene open reading frame was composed of 1 353 nucleotide residues to code 450 amino acids (20 kinds), the accession number submitted to the Genbank was HM756692, its sequence homology of nucleotides and amino acids compared with the vaccine strain CTN-1-V was 90% and 99% respectively. The evolutionary analysis showed that the isolated strain belonged to genotype I with certain geographic regionality. CONCLUSION The characteristics investigation and bioinformatics analysis of Hunan0806 N gene will provide fundamental data to reveal the significance of the N gene characteristics for rabies epidemiology and its prevention & control.

Investigation and analysis of rabies viral infection and distribution in China in 2005–2012

We report the results of a preliminary investigation of data collected between 2005 and 2012. A National Human Rabies Surveillance program was initiated in high rabies incidence regions in 2005, and subsequently carried out nationally to monitor rabies situation. Our work presents a summary of epidemiological and etiologic rabies surveillance data collected since the implementation of the program.

A triplex quantitative real-time PCR assay for differential detection of human adenovirus serotypes 2, 3 and 7

BackgroundHuman adenovirus (HAdV) serotypes 2, 3 and 7 are more prevalent than other serotypes and have been associated with severe pneumonia in pediatric children. Molecular typing of HAdV is not routinely performed in clinical diagnostic laboratories as it is time-consuming and labor-intensive.MethodsIn the present study, we developed a triplex quantitative real-time PCR assay (tq-PCR) in a single closed tube for differential detection and quantitative analysis of HAdV serotypes 2, 3 and 7. The sensitivity, specificity, reproducibility and clinical performance of tq-PCR were evaluated.ResultsThe analytical sensitivity of the tq-PCR was 100 copies/reaction for each of HAdV serotypes 2, 3 and 7, and no cross-reaction with other common respiratory viruses or HAdV serotypes 1,4,5,6,31,55 and 57 was observed. The coefficients of variation (CV) of intra-assay and inter-assay were between 0.6% to 3.6%. Of 138 previously-defined HAdV-positive nasopharyngeal aspirates samples tested, the detection agreement between tq-PCR and nested PCR was 96.38% (133/138).ConclusionThe proposed tq-PCR assay is a sensitive, specific and reproducible method and has the potential for clinical use in the rapid and differential detection and quantitation of HAdV serotypes 2, 3 and 7.

Epidemic of rabies and effect of its vaccine against a dog that consecutively attacked ten people in one day.

doi: 10.3967/ bes2014.017 1. Hunan Center for Disease Control and Prevention, Key Laboratory of Microbial Molecular Biology of Hunan Province, Changsha 410005, Hunan, China; 2. Key Laboratory for Medical Virology, Ministry of Health, Institute for Viral Disease Control and Prevention, China CDC, Beijing 102206, China; 3. Yongzhou Center for Disease Control and Prevention, Yongzhou 425000, Hunan, China; 4. Ningyuan Center for Disease Control and Prevention, Yongzhou 425600, Hunan, China Letter to the Editor