Search

Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato, spotted fever group (SFG) rickettsiae, and Francisella tularensis are the causative agents of human granulocytic anaplasmosis, Lyme disease, spotted fever, and tularemia, respectively. These [...]

Single nucleotide variations (SNVs) at 5 loci (17564, 21721, 22222, 23823, and 27827) were used to define the molecular epidemiologic characteristics of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) from Beijing [...]

Abstract Background Japanese encephalitis (JE) vaccination is the most effective measure for preventing JE disease. The live attenuated JE vaccine, which has shown good efficacy and safety, has been widely used in China. Case presentations We report four laboratory-confirmed JE cases detected in JE-endemic areas during the JE virus (JEV) transmission season, who all received a first dose of live attenuated JE vaccine within 2 weeks prior to the onset of illness. All cases presented with acute encephalitis and rapidly reduced consciousness. All cerebrospinal fluid (CSF) samples from the patients were positive for JEV-specific immunoglobulin M (IgM) antibodies, but viral isolation and polymerase chain reaction (PCR) detection of JEV were both negative. Conclusions It is difficult to identify a causal link between the disease and the vaccination, as the source of positive CSF JEV IgM antibodies might be natural JEV infection or possibly due to a traumatic lumbar puncture. Our observations highlight the need for public health officers and doctors to consider reasonable vaccination policies during the JE season. In addition, continued surveillance as well as thorough investigation of any events that occur after JE vaccination is necessary.

Abstract Background Before 1986, scrub typhus was only found endemic in southern China. Because human infections typically occur in the summer, it is called "summer type". During the autumn-winter period of 1986, a new type of scrub typhus was identified in Shandong and northern Jiangsu province of northern China. This newly recognized scrub typhus was subsequently reported in many areas of northern China and was then called "autumn-winter type". However, clinical characteristics of associated cases have not been reported. Methods From 1995 to 2006, all suspected scrub typhus cases in five township hospitals of Feixian county, Shandong province were enrolled. Indirect immunofluorescent assay (IFA) was used as confirmatory serodiagnosis test. Polymerase chain reaction (PCR) connected with restriction fragment length polymorphism (RFLP) and sequence analyses were used for genotyping of O. tsutsugamushi DNAs. Clinical symptoms and demography of confirmed cases were analyzed. Results A total of 480 scrub typhus cases were confirmed. The cases occurred every year exclusively between September and December with a peak occurrence in October. The case numbers were relatively higher in 1995, 1996, 1997, and 2000 than in other years. 57.9% of cases were in the group aged 21–50. More cases occurred in male (56%) than in female (44%). The predominant occupational group of the cases was farmers (85.0%). Farm work was reported the primary exposure to infection in 67.7% of cases. Fever, rash, and eschar were observed in 100.0%, 90.4%, and 88.5% of cases, respectively. Eschars formed frequently on or around umbilicus, abdomen areas, and front and back of waist (34.1%) in both genders. Normal results were observed in 88.7% (WBC counts), 84.5% (PLT counts), and 89.7% (RBC counts) of cases, respectively. Observations from the five hospitals were compared and no significant differences were found. Conclusion The autumn-winter type scrub typhus in northern China occurred exclusively from September to December with a peak occurrence in October, which was different from the summer type in southern China. In comparison with the summer type, complications associated with autumn-winter type scrub typhus were less severe, and abnormalities of routine hematological parameters were less obvious.

This study investigated the long-term excretion of severe acute respiratory syndrome-associated coronavirus in sputum and stool specimens from 56 infected patients. The median (range) duration of virus excretion in sputa [...]

To characterize the strains of Anaplasma phagocytophilum in wild and domestic animals in China, we isolated the organism from rodents and sheep in northeastern China. We isolated 3 strains (2 from rodents and 1 from sick sheep) through propagation in BALB/c mice and then cell culture in HL60 cells. The 3 isolates were identified by Wright-Giemsa staining, immunofluorescence, and electronic microscopy and were characterized by sequence analyses of the 16S rRNA gene, partial citrate synthase gene, major surface protein 4 gene, and heat shock protein gene. The multiple sequences of the 3 isolates were identical to each other but different from all known strains from other countries. The public health and veterinary relevance of the isolates deserves further investigation.

Objective: To further understand the association of hantavirus (HV) harbored and transmitted in wild brown rats., Methods: Rattus norvegicus (n = 570) were trapped in 10 sites in Beijing. RT-PCR was used to test rodent lung samples for hantavirus infection. Unconditional multivariate logistic regression analysis was performed, with PCR positive as the dependent variable and the characteristics of Rattus norvegicus population as independent variables., Results: The overall HV prevalence in Rattus norvegicus was 9.1% (52/570). Significant association between HV infection in Rattus norvegicus and some biological characteristics of host population was observed. Adult Rattus norvegicus had a higher HV prevalence than juveniles. Males in the reproduction periods and rats with wounds were more likely to be infected with HV than others., Conclusion: It was further confirmed that there existed parallel transmission of HV in Rattus norvegicus hosts. Aggression might be the primary mode of HV transmission among male Rattus norvegicus.

Objective: In order to find out the factors related to hemorrhagic fever with renal syndrome (HFRS) infection, and to evaluate the probability of ecdemic hantaviruses (HV) infection in rodents in Beijing areas., Methods: Rodents were collected in a large-scale railway station and a produce market with 'trap nights' method from April to May, 2004. The IgG reacting sera to HV antigen were detected using ELISA. The partial M and S segment of HV from captured rodent lung samples were amplified with RT-PCR. The PCR products were purified and sequenced. BLAST program was then used to perform on nucleotide pairwise alignment with all available sequence in GenBank. The alignment of the multiply nucleotide and the deduced amino acid sequences, together with phylogenetic analysis were completed with DNASTAR software., Results: The average population density was 3.49% (24/690). The overall seroprevalence of HV infection was 8.3% (2/24). RT-PCR positive rates were 8.3% (2/24). The nucleotide sequences of 356 bp region (1958 - 2313) of M segment obtained from 2 samples were all identified to Seoul virus (SEOV), with 7.6% heterogeneity. The dc501 strain from railway station was closely related to SD227 and Hebei4 from Shandong and Hebei provinces respectively. BjFT01 strain from the farm product market had more special nucleotide transitional mutations than other known SEOV from Beijing in GenBank. This strain, together with known HN71 from Hainan province, K24-E7 from Zhejiang province, L99 from Jiangxi province and R22 from Henan province, represented a monophylogentic linkage., Conclusion: The higher HV prevalence of rodents in transportation center was the potential and important risk for HFRS epidemic in Beijing. The increasing prevalence of M. musculus should call for attention. It was possible that SEOV in Beijing was imported by infected rodents through vehicles from other provinces.

Objective: To investigate hantanvirus infection of captured rodents in Haidian district and Changping district of Beijing and to type hantavirus using molecular technique., Methods: The captured mice were classified and the density of distribution was calculated. Reverse transcription-polymerase chain reaction (RT-PCR) technique was used to amplify the partial M fragnments of hantaviruse. Several representative positive samples were sequenced and analysed by ClustalX (5.0) and DNAClub software., Results: A total of 414 animals were captured, among which Battus norvegicus was the dominant group. In Haidian district, the median infection rates with hantavirus were 13.14% in Battus norvegicus and 0 in Mus musculus Linnaeus. In Changping district, the average infection rates were 17.46% in Battus norvegicus and 3.57% in Mus musculus Linnaeus. Nucleotide sequences analysis showed that the virus detected all belonged to SEO-type. They clustered with Z37 virus and could be branched into 2 different subclades., Conclusion: The major hosts of hantavirus in Haidian and Changping district were Battus norvegicus and the epidemic strains in the two districts of Beijing were genotyped as SEO-type. Nucleotide sequence and deduced amino acid sequence from different rodents were highly homologous, while nucleotide mutation had also been observed. Further studies are required to explore the possible virus sequence mutation.

Objectives: To study the correlation between positive rates of RNA in clinical confirmed severe acute respiratory syndrome (SARS) patients and its appearance in relation to the development of the disease in order to provide scientific basis for early diagnosis, effective prevention and treatment of the disease., Methods: One-step reverse transcription-polymerase chain reaction (RT-PCR) was used to amplify the SARS RNA in the clinical specimens from different courses of the disease. The representative amplicons were then sequenced. Chi-square for trend test was performed to study the correlation between positive rates of RT-PCR and at different periods after the onset of the disease., Results: The fragments amplified from the sputum specimens of SARS patients were shown to share 100% homology with the published SARS-associated coronavirus. Of the different clinical specimens, positive rate in the stools appeared to be the highest (21.55%). Chi-square for trend test revealed that the positive rates of stools and sputa of SARS patients decreased with the development of the disease (chi(2) for trend = 12.55 and 16.408, P = 0.0004 and P = 0.000 05 respectively)., Conclusion: One-step RT-PCR proved to be an effective method for the detection of SARS-associated coronavirus from clinical specimens. Data as indicated that the positive rates of SARS coronavirus were decreasing in SARS patients along with the disease progression.