Analysis on Factors Related to Rabies Epidemic in China from 2007-2011

To analyze features of the rabies epidemic in China between 2007 and 2011, identify factors influencing the epidemic and to provide a scientific basis for further control and prevention of rabies, Descriptive epidemiological methods and statistical analysis was used on data collected from the National Disease Reporting Information System between 2007 to 2011 and the National Active Surveillance System between 2007 and 2010. Our analysis shows that while the number of human rabies cases decreased year by year, the number of districts reporting cases did not show significant change. The situations in Guangdong, Guangxi, Guizhou and Hunan provinces clearly improved over the period but they remain provinces with high-incidence, and consequently influence the epidemic situation of surrounding provinces and possibly the whole country. Summer and autumn were high-incidence seasons. Farmers, students and pre-school children represent the high-risk populations, and rates of cases in farmers increased, those for students decreased, and pre-school children remained unchanged. Provinces with active surveillance programs reported a total of 2346 individual cases, of which 88.53% were associated with canines. Postexposure prophylaxis （PEP） of rabies cases was not significantly improved, whereas PEP in post-exposure population was good. In rural regions of China, canine density was reduced somewhat, and the immunization rate increased slightly. Finally we show that while the epidemic decreased 2007 to 2011 in China, cases continued to be diffused in certain regions. Lack of standardization of PEP on rabies eases was the main reason of morbidity. The high density and low immunization of dog in rural areas and the defective situation of PEP are still continuous occurrences in China and remain a cause for concern.

Molecular cytogenetic study on the plants of Elymus nutans with varying fertility on the Qinghai-Tibet Plateau

A molecular cytogenetic investigation was conducted on plants of the allohexaploid species Elymus nutans with varying fertility on the Qinghai-Tibet Plateau.Molecular karyotyping revealed that chromosome variants were distributed unevenly among genomes and among different homologue chromosomes in each genome.The plants with varying fertility exhibited significantly higher numbers of chromosome variants than did the normal fertility samples,although both kinds of plants showed the same pattern of high-to-low polymorphism from the Y to St and H genomes.Heterozygosis and karyotype heterozygosity in the plants with varying fertility were 3-and 13-fold higher than those in normal samples,respectively.Significant negative correlations were found not only between seed setting rates and total genome heterozygosity but also between seed setting rates and heterozygosity of each genome in the plants of varying fertility.Chromosome pairing analysis was performed using genomic in situ hybridization in selected plants of different fertility levels.The pairing of chromosomes at meiotic metaphase I was mostly bivalent,although univalent,trivalent,quadrivalent,and other polyvalents also occurred;in addition,chromosome configuration forms and frequencies varied among the studied samples.ANOVA results showed that the average number of ring bivalents in the Y genome was significantly higher than those in the St and H genomes.Significant positive correlations between pollen grain fertility and ring bivalent number were found in the St and H genomes but not in the Y genome.Furthermore,chromosome configuration parameters(total bivalents,numbers of ring and rod bivalents)were found to be significantly correlated with heterozygosity and seed setting rates in the St and H genomes,respectively,but not in the Y genome.It was inferred that the seed setting rate and pollen grain fertility in E.nutans are strongly influenced by the heterozygosity of each genome,but the Y genome differs from the St and H genomes due to chromosome pair alterations.The St and H genomes may contain more chromosome structural variations than the Y genome in E.nutans.

Construction and Identification of the Helper Plasmids for Reverse Genetic System of Rabies Virus Street Strain

To obtain the helper plasmids for a reverse genetics system of rabies virus, the cDNAs of the complete open reading frames of the N, P, G, and L genes of rabies street virus stain HN10 were each cloned into expression vector pVAX1, These four plasmids were identified by restriction enzyme digestion and gene sequencing. The plasmid encoding the N protein was selected to determine the expression effect of these plasmids in NA cells. The results showed that the helper plasmids for a reverse genetics system of rabies street virus strain HN10 had been successfully constructed.

Human rabies in China:evidence-based suggestions for improved case detection and data gathering

Background:China still suffers heavily from rabies,although reported human cases continue to decrease year over year.There are far fewer laboratory-confirmed human cases than clinically diagnosed cases,which is a big problem that needs to be addressed.In this report,we summarize analyses of all specimens from human cases tested in our laboratory over the past 15 years,in order to promote laboratory diagnosis of rabies.Methods:From 2005 to 2019,a total of 271 samples from 164 suspected rabies cases were collected from local hospitals by the local Centers for Disease Control and Prevention(CDCs)in China.Saliva,cerebrospinal fluid(CSF),serum(blood)and urine were collected for ante-mortem diagnosis,and brain tissue,neck skin tissue and cornea were collected for post-mortem diagnosis.All of the specimens were tested by reverse transcription-polymerase chain reaction(RT-PCR),and brain tissues were also tested using fluorescent antibody test(FAT).The number of positive test results obtained using different fluids or tissues,and at different stages of the disease,were compared using a chi-square test and a more effective sampling program is recommended.Results:As the national reference laboratory for rabies surveillance in China,our laboratory has tested 271 samples from 164 suspected rabies cases collected by local CDCs since 2005.We found that saliva gave the highest number of positive test results(32%),compared with CSF and other fluids.We also found that serum or blood specimens collected in the last 3 days of life can test positive by RT-PCR.Conclusions:Serum or blood samples collected in the last 3 days of a patient’s life can be used to measure viral RNA,which means that serum samples,as well as saliva and CSF,can be used to detect viral RNA for anti-mortem diagnosis of rabies.Because of our findings,we have modified our“National Surveillance Project for Human Rabies”,by adding the collection and testing of serum samples from the end of the survival period.This will improve our national surveillance and laboratory diagnosis of human rabies.

Establishment of a Chinese street rabies virus library and its application for detecting neutralizing activity

Background:The injection of rabies immune globulin(RIG)is of the utmost importance in the management of category III exposures to rabies-suspect animals.Because of the high cost and limited availability of existing RIG,one possible replacement for RIG is monoclonal antibodies(MAbs)against the rabies virus(RABV).Consequently,it is necessary to determine the neutralizing activity of the MAbs against rabies viruses,especially street rabies virus.However,the method to detect the neutralizing activity of MAbs against street rabies virus remains undefined.Methods:To establish a method for detecting the neutralizing activity of MAbs against street rabies virus,we constructed a library consisting of 12 strains of street RABV from 11 provinces in China.Using this street RABV library and the Reed-Muench formula,we established a method for detecting the neutralizing titer of the MAbs.The reliability and repeatability of the method were evaluated by repeatedly measuring the neutralizing activity of a MAb and a post vaccination serum.Results:A total of 12 strains of street RABV were chosen for inclusion in the street RABV library,which covered six Chinese lineages(China I-China VI)and grew to high titers in N2A cells(>105 FFD50/ml).On the basis of the library,we constructed the method to detect the neutralizing activity of the MAbs.The results of repeatedly measuring the MAbs and positive serum showed excellent reliability and repeatability of the method established in this study.Conclusions:This study established a street RABV library reflecting the epidemiological features of Chinese rabies viruses,which provides a platform for detecting the neutralizing activity of MAbs against rabies viruses circulating in China.