A family cluster of infections by a newly recognized bunyavirus in eastern China, 2007: further evidence of person-to-person transmission.

BACKGROUND: Seven persons in one family living in eastern China developed fever and thrombocytopenia during May 2007, but the initial investigation failed to identify an infectious etiology. In December 2009, a novel bunyavirus (designated severe fever with thrombocytopenia syndrome bunyavirus [SFTSV]) was identified as the cause of illness in patients with similar clinical manifestations in China. We reexamined this family cluster for SFTSV infection. METHODS: We analyzed epidemiological and clinical data for the index patient and 6 secondary patients. We tested stored blood specimens from the 6 secondary patients using real time reverse transcription polymerase chain reaction (RT-PCR), viral culture, genetic sequencing, micro-neutralization assay (MNA), and indirect immunofluorescence assay (IFA). RESULTS: An 80-year-old woman with fever, leucopenia, and thrombocytopenia died on 27 April 2007. Between 3 and 7 May 2007, another 6 patients from her family were admitted to a local county hospital with fever and other similar symptoms. Serum specimens collected in 2007 from these 6 patients were positive for SFTS viral RNA through RT-PCR and for antibody to SFTSV through MNA and IFA. SFTSV was isolated from 1 preserved serum specimen. The only shared characteristic between secondary patients was personal contact with the index patient; none reported exposure to suspected animals or vectors. CONCLUSIONS: Clinical and laboratory evidence confirmed that the patients of fever and thrombocytopenia occurring in a family cluster in eastern China in 2007 were caused by a newly recognized bunyavirus, SFTSV. Epidemiological investigation strongly suggests that infection of secondary patients was transmitted to family members by personal contact.

[The application of molecular differential diagnoses platform in identification of the respiratory pathogens].

AIM: To establish a MDD (molecular differential diagnoses) platform for diagnosing the pathogens that may cause respiratory infection by combination of the advanced Tem-PCR(Target enriched multiplex PCR)with xMAP(multiple analyses profiling), and to evaluate the reliability and further use the platform to test clinic samples. METHODS: 22 throat swab specimen from outpatient patients of respiratory department in First Affiliated Hospital of Suzhou University and 20 respiratory tract lavage fluid specimen from inpatients of respiratory department in Affiliated Children Hospital of Suzhou University were collected, and the nucleic acids of the samples were amplified by Tem-PCR and xMAP. RESULTS: Testing of the the known samples showed that the platform had excellent specificity and sensitivity. Testing of the clinic samples showed that the positive rate of the respiratory tract lavage fluid specimen was 63.6%, higher than that of the throat swab specimen, and that the positive rate of RNA pathogens was higher than that of DNA pathogens. CONCLUSION: A reliable MDD platform for detection of respiratory pathogens has been established with high-throughput detection capacity.

Pleiotropic effect of tatC mutation on metabolism of pathogen Yersinia enterocolitica.

OBJECTIVE: To analyze the impact of depletion of the twin arginine translocation (TAT) system on virulence and physiology of Yersinia enterocolitica for a better understanding of its pathogenicity. METHODS: We constructed a DeltatatC::SpR mutant of Yersinia enterocolitica by P1 phage mediated transduction using Escherichia coli K-12 DeltatatC::SpR strain as a donor. RESULTS: A P1-mediated genetic material transfer was found between the two species of enterobacteria, indicating a great potential of acquisition of antibiotic resistance in emergency of a new threatening pathogen by genetic material exchanges. Periplasmic trimethylamine N-oxidase reductase activity was detected in the wild type Y. enterocolitica strain and translocation of this enzyme was completely abolished by the DeltatatC::SpR mutation. In addition, the DeltatatC::SpR mutation showed a pleiotropic effect on the metabolism of Y. enterocolitica. However, the tat mutation did not seem to affect the mobility and virulence of Y. enterocolitica under the conditions used. CONCLUSION: Unlike other pathogenic bacteria studied, the TAT system of Y. enterocolitica might play an important role in the pathogenic process, which is distinct from other pathogens, such as Pseudomonas aeruginosa and enterohemorrhagic E. coli O157:H7.

[Etiology of aseptic meningitis prevalent in Xuzhou].

BACKGROUND: To find the pathogenic agents of aseptic meningitis prevalent in Xuzhou of Jiangsu province in 2001. METHODS: The enterovirus (EV) was cultured from CSF of the patients and identified with anti-serum by neutralization test. Neutralization titer of antibody in paired sera from meningitis children was determined. EV RNA was detected by RT-PCR. RESULTS: Four strains of Coxsackievirus B5, 2 strains of Coxsackievirus B3 and 1 strain of Echovirus 7 were isolated from 22 CSF specimens. The isolation rate of virus was 31.8% (7/22), 21 CSF were tested by RT-PCR, the positive rate of EV RNA was 52.4% (11/21); 57.9% (11/19) of patients paired-sera had over 4 folds antibody rise or became seroconverted. CONCLUSION: Enterovirus was the pathogenic agent of aseptic meningitis prevalent in Xuzhou of Jiangsu province, the main serotype of the virus was Coxsackievirus B5.

[Preliminary study on nasal spray of interferon alpha-2b used for prevention of rubella and measles virus infections].

OBJECTIVE: To evaluate the efficacy of the interferon alpha-2b nasal spray in prevention of rubella and measles virus infections. METHODS: The properly selected volunteer groups have been divided into interferon alpha-2b experimental and control group. The experimental group received interferon alpha-2b treatment by nasal spray for 2 days before the immunization, then both groups were challenged with rubella and measles attenuated live vaccine respectively through nasal spray. The sera from pre-immunization and 21 and 28 days after immunization were collected to test the IgG antibody titers. The influence on the viral antibody titer reflects the viral preventive effect by interferon alpha-2b. RESULTS: The antibody titer difference of measles virus between experimental and control group was 1.26 (21 day) and 2.96 (28 day), there were statistically difference between them; the difference of rubella virus was 0.95 (21 day) and 0.37 (28 day), but there were no statistically differences found. CONCLUSION: The preliminary results showed that the interferon alpha-2b can be used as prevention method for measles and rubella viral infections.

[Study on the distribution of Yersinia enterocolitica in Nantong, Jinagsu Province].

OBJECTIVE: To study the distribution of Yersinia enterocolitica and its virulence factors in Nantong, Jiangsu. METHODS: Yersinia strains were isolated from livestock and poultry. Conventional PCR was used to detect the virulence factors of all strains and strain 0:8 was analyzed by pulsed-field gel electrophoresis(PFGE). RESULTS: The combined isolation rate of Yersinia enterocolitica from livestock and poultry was 31.06% and the gene distribution characters were: 39.57% of them were ail-, ystA- , ystB-, yadA- , virF-; 60.43% were ail- , ystA- , ystB + , yadA- , virF- respectively. The two reference strains from America and Denmark showed similar electrophoresis patterns but were significantly different with O:8 strains isolated from China while the serotypes of Yersinia enterocolitica O:3 and O:9 which were the main epidemic strains in China, were not found in this area. CONCLUSION: The pathogenic Yersinia enterocolitis O:3 and O:9 were not found in Nantong,Jiangsu province.

[Epidemiological study on an outbreak caused by E. coli O157:H7 in Jiangsu province].

OBJECTIVE: To carry out epidemiological study on an outbreak caused by E. coli O157:H7 infection in Jiangsu province in 1999. METHODS: Epidemiological, microbiological and moleculebiological methods were used to find out the source, route of transmission and risk factors. RESULTS: 95 severe O157:H7 infected patients with acute renal failure in 9 counties and districts of 2 municipalities were reported in Jiangsu province, 1999 while 83 of the patients died with a death rate of 87.37%. Most patients were seen in mid or late June. The ratio of male to female was 1 to 1.44 and 88.42% of the patients were over 50 years old. 38 patients occurred in 2000 with 34 deaths. Major factors contributing to the outbreak would include without drinking tap water, eating leftover food, poor sanitary status in kitchen, not washing hands before meal and after bowl movement. 2 strain of O157:H7 was isolated from severe patients and 3 from diarrhea cases. Carrier rate among animals was up to 9.62% and 99.41% of the strains carried toxic gene. Strains isolated from feces of patients and animals belonged to the same colonies. CONCLUSION: This outbreak was severe which caused by O157:H7 and was first seen in China, which was closely related to the high carrier rate of O157:H7 in animals and to the positive rate of high toxic gene of the strains. There were various routes of transmission and the main factors of infection would include poor personal health habits and poor sanitation of the household.