Visual Detection of Vibrio parahaemolyticus using Combined CRISPR/Cas12a and Recombinase Polymerase Amplification / 生物医学与环境科学（英文）

Objective@#To establish an ultra-sensitive, ultra-fast, visible detection method for Vibrio parahaemolyticus (VP) .@*Methods@#We established a new method for detecting the tdh and trh genes of VP using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 12a (CRISPR/Cas12a) combined with recombinase polymerase amplification and visual detection (CRISPR/Cas12a-VD).@*Results@#CRISPR/Cas12a-VD accurately detected target DNA at concentrations as low as 10 -18 M (single molecule detection) within 30 min without cross-reactivity against other bacteria. When detecting pure cultures of VP, the consistency of results reached 100% compared with real-time PCR. The method accurately analysed pure cultures and spiked shrimp samples at concentrations as low as 10 2 CFU/g.@*Conclusion@#The novel CRISPR/Cas12a-VD method for detecting VP performed better than traditional detection methods, such as real-time PCR, and has great potential for preventing the spread of pathogens.

Risk factors for death in children with severe hand, foot and mouth disease / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the death risk factors in children with severe hand, foot and mouth disease (HFMD).</p><p><b>METHODS</b>A total of 164 children with severe HFMD between May 2010 and September 2012 were recruited and classified into death and survival groups according to their prognosis. The differences in general information, clinical signs and symptoms and laboratory examinations were compared between the two groups. The multivariate logistic regression analysis was used to identify death risk factors in children with severe HFMD.</p><p><b>RESULTS</b>There were significant differences in the incidences of atypical rash, persistent fever, dyspnea, pulmonary hemorrhage, heart rate increase, blood pressure abnormalities, cold sweat, capillary refill time>3 seconds and frequent seizures, and blood glucose, serum creatine kinase and serum lactate levels between the death and the survival groups (P<0.05). The multivariate logistic regression analysis showed three independent death risk factors for children with severe HFMD: pulmonary hemorrhage (OR=9.466, 95%CI: 1.786-21.256), abnormal blood pressure (OR=5.224, 95%CI: 1.012-28.985) and elevated serum lactate level (OR=2.154, 95%CI: 1.020-8.253).</p><p><b>CONCLUSIONS</b>Pulmonary hemorrhage, abnormal blood pressure and elevated serum lactate are major death risk factors for children with severe HFMD.</p>

Analyses on one case of severe acute respiratory syndrome 'super transmitter' and chain of transmission / 中华流行病学杂志

<p><b>OBJECTIVES</b>To investigate the transmission process of severe acute respiratory syndrome (SARS) and to evaluate the infectiveness of SARS patients in different periods of disease epidemics.</p><p><b>METHODS</b>Standardized questionnaire was used to conduct case investigation and contact tracing by combining the field investigation and telephone interview. Transmission process, infectivity, transmission chain and contact history of SARS were studied through data analyses.</p><p><b>RESULTS</b>On 25th March 2003, a 91 year old man was admitted to Hospital J in Beijing with stroke and fever. He died on 30th March. From 31st March, there was an outbreak of SARS among his contacts in the family and in the hospital he was admitted to. Contacts would include his relatives, other co-patients and health care workers in the Hospital J. Chinese Field Epidemiology Training Program trainees conducted an investigation of the outbreak. Among the 207 contacts of the index cases through different generations, there were 36 cases of SARS (attack rate 17%) patients with one death. There were 12 cases having directly contact with the index case and 13 cases with one secondary case. The transmission chains of this outbreak could clearly be depicted. All the cases had close contacts during the symptomatic period of their index patients. Among the relatives, 85% of the cases had 3 - 5-day contact with their index patients after the onset of the illnesses. There was no significant difference between the two attack rates-70% for whose who had contact with the patient before and after illness onset) and 67% for those who only had contact after the onset of the illness. Out of the 44 social acquaintances and 38 of the family members who had contacts with the index patients during the incubation period, no one was found ill. Among the close contacts at the hospital who had no protection when providing care to the patient, the attack rate was found over 80%.</p><p><b>CONCLUSIONS</b>All the secondary cases of this outbreak had a history of direct and close contacts to the index patients after the onset of the illness. There was no evidence indicating that SARS cases were infectious during their incubation period.</p>