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Objective@#To find out the source and the epidemic pattern of norovirus outbreak in July, 2016 to June, 2017 in Guangzhou.@*Methods@#The stool samples and clinical information of diarrhea cases were collected by the sentinel hospitals and CDCs; a real-time RT-PCR method was used to detect the norovirus nucleic acids from the samples, the positive ones were amplified and sequenced; the partial sequences of norovirus were aligned by an online BLAST alignment, and a phylogenetic tree was constructed by a neighbor-joining method .@*Results@#A total of 854 cases with infectious diarrhea were reported by Guangzhou diarrhea surveillance network from July, 2016 to June, 2017; the gender ratio (male versus female) was 1∶0.67; 78.33% of the cases were preschool children under the age of 7 years. Totally 220 samples were detected norovirus G II+ (25.76%, including 5 double-positive samples with G I+ ). GII.Pe-GII.4.Sydney_2012 was the prevalent genotype in the second half of 2016 (94.64%), which was replaced by GII.P16-GII.2 in the first half of 2017 (67.65%). Since September 2016, the reported number of norovirus-caused diarrhea epidemic was increased gradually; the peak of epidemic curve emerged in February to March of 2017, and the number started to decrease since April. In May to June there were only 2-3 epidemics reported monthly. All the endemics from September to November 2016 were caused by genotype GII.Pe-GII.4.Sydney_2012; the endemics from December 2016 to April 2017 were mainly caused by genotype GII.P16-GII.2. Some samples from kitchen workers and babysitters were detected GII+ , which was consistent with the result of the cases′ samples.@*Conclusions@#It was the first time that the novel GII.P16-GII.2 recombinant strain outbroke occurred in Guangzhou City and homology analysis also suggested that GII.P16-GII.2 was the main source of those epidemics in 2016 -2017 winter and spring season. Furthermore, The kitchen workers and babysitters may have played an important role in the spread of norovirus.
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Objective To understand the epidemiological and molecular characteristics of a norovirus-borne outbreak caused by GⅡ.4 Sydney 2012 in a university of Guangzhou to provide evidence for the prevention and control strategy on norovirus-caused epidemics.Methods A self-designed questionnaire was used to collect clinical information from the patients as well as other data related to the epidemic.Pathogen detections were performed through anal swab specimens from the patients,kitchen workers and samples from the environment.Positive samples were further sequenced for phylogenetic analysis.A case-control study was employed to identify the risk factors related to this outbreak.Results A total of 226 cases of norovirus-borne infection were identified between September 17 and 21,2017,including 223 students,with an attack rate of 0.73％ (223/30 711),and 3 kitchen workers.Students staying in the A dormitory area had the highest attack rate (1.73％,164/9 459).No clustering was found in different colleges or classes.Results from the case-control study revealed that people who ate at the canteen in A dormitory area during September 18 to 20 was at risk for the onset of illness (OR=10.75,95％CI:5.56-20.79).The highest risk was related to the dinner on September 18.Another significant risk factor (OR=3.65,95％ CI:1.92-6.94) was close personal contact in the same room of the dorm.The 3 norovirus infected kitchen workers were all from the canteen in A dormitory area where the positive rate of norovirus identified in kitchen workers was 26.67％ (12/45).Positive samples were sequenced and sub-typed with results showing that the GⅡ.4 Sydney 2012 variant and the nucleotide sequences of cases and kitchen workers were 100％ identical.Conclusions The outbreak was caused by norovirus GⅡ.4 Sydney 2012 variant at campus.Similar outbreaks had been seen since 2013,with the routes of transmission most likely due to food-borne or personal contact.
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Objective To understand the epidemiological and molecular characteristics of a norovirus-borne outbreak caused by GⅡ.4 Sydney 2012 in a university of Guangzhou to provide evidence for the prevention and control strategy on norovirus-caused epidemics.Methods A self-designed questionnaire was used to collect clinical information from the patients as well as other data related to the epidemic.Pathogen detections were performed through anal swab specimens from the patients,kitchen workers and samples from the environment.Positive samples were further sequenced for phylogenetic analysis.A case-control study was employed to identify the risk factors related to this outbreak.Results A total of 226 cases of norovirus-borne infection were identified between September 17 and 21,2017,including 223 students,with an attack rate of 0.73％ (223/30 711),and 3 kitchen workers.Students staying in the A dormitory area had the highest attack rate (1.73％,164/9 459).No clustering was found in different colleges or classes.Results from the case-control study revealed that people who ate at the canteen in A dormitory area during September 18 to 20 was at risk for the onset of illness (OR=10.75,95％CI:5.56-20.79).The highest risk was related to the dinner on September 18.Another significant risk factor (OR=3.65,95％ CI:1.92-6.94) was close personal contact in the same room of the dorm.The 3 norovirus infected kitchen workers were all from the canteen in A dormitory area where the positive rate of norovirus identified in kitchen workers was 26.67％ (12/45).Positive samples were sequenced and sub-typed with results showing that the GⅡ.4 Sydney 2012 variant and the nucleotide sequences of cases and kitchen workers were 100％ identical.Conclusions The outbreak was caused by norovirus GⅡ.4 Sydney 2012 variant at campus.Similar outbreaks had been seen since 2013,with the routes of transmission most likely due to food-borne or personal contact.
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<p><b>OBJECTIVE</b>To identify the pathogen and characteristics on a case of hand-foot-mouth disease (HFMD) caused by coxsackie-virus A6 (CA6) associated with vaccine-derived poliovirus (VDPV) co-infection.</p><p><b>METHODS</b>Field epidemiological study at the epidemic area was conducted and 16 stool samples including from the patient and close contacts were collected for isolation and identification of the enterovirus (EV). 21 stool samples from patients diagnosed as HFMD were collected in the same hospital at the same month to detect CA16,EV71, CA6 and PV by real-time RT-PCR or RT-PCR. The VP1 gene of the CA6 was amplified by RT-PCR and PCR products were sequenced and analyzed.</p><p><b>RESULTS</b>The patient showed only HFMD symptoms, but no symptoms related to acute flaccid paralysis (AFP). No EVs were isolated from 16 samples collected from the patient and close contacts. And no AFP cases were found by an active search. A total of 21 samples from patients diagnosed as HFMD were collected in the same hospital at the same month and 4 were found to be EV71, 2 were CA16 and 15 (include the patient)were CA6. Only this patient was found to have had VDPV II infection. The CA6 VP1 gene was amplified from the HFMD patient and 9 other cases from the same hospital at the same month. Nucleotide sequences of the VP1 gene among the 9 strains shared 98.9%-100.0% in homology and 96.0%-100.0% in the deduced amino acid sequences. Phylogenetic analysis of the VP1 sequences categorized the 9 strains into the same branch. There were 6 nucleotides changes including U2909A between the VP1 region of the VDPV strain of the case and Sabin II. Results from phylogenetic analysis on the VP1 sequences indicated that the VDPV strain of the case was different from other VDPVs strains isolated in the world.</p><p><b>CONCLUSION</b>This case was a HFMD which caused by CA6 co-infection with VDPV II and the VDPV was newly discovered. HFMD symptoms of the case were caused by CA6. The reason why this case did not have AFP symptoms was probably due the protective effect of IPV vaccine. No AFP cases were found by the active search for AFP cases conducted in the area, which indicated that VDPV did not cause virus circulation in this area.</p>
Subject(s)
Child, Preschool , Female , Humans , Coinfection , Enterovirus A, Human , Hand, Foot and Mouth Disease , Virology , Poliovirus VaccinesABSTRACT
<p><b>OBJECTIVE</b>To identify the enterovirus from stool samples of patients with hand, foot and mouth disease(HFMD) in Guangzhou from 2010 to 2012 and to perform phylogenetic analysis of the VP1 gene sequences of coxsackievirus A4 and coxsackievirus A10.</p><p><b>METHODS</b>A total of 5 484 samples of suspected cases of HFMD which Guangzhou Center for Disease Control received from 2010 to 2012 were collected.Virus RNA was tested by nested RT-PCR method as human enterovirus 71, coxsackievirus A16, coxsackievirus A4, coxsackievirus A10 and other enteroviruses positive, and 4 111 samples were positive. Phylogenetic tree was constructed by partial VP1 gene sequences of coxsackievirus A4 and coxsackievirus A10 to perform phylogenetic analysis.</p><p><b>RESULTS</b>In 4 111 enterovirus-positive samples, the positive rate of EV71, CoxA16, CoxA10 and CoxA4 was 35.1% (1 443/4 111) , 30.7% (1 261/4 111) , 2.0% (82/4 111),0.8% (31/4 111) respectively. Different enterovirus-positive rate was statistically significant (χ(2) = 148.34, P < 0.05) .Incidences of coxsackievirus A4 positive was highest in 3-year old children as 1.3% (7/534) , and that of coxsackievirus A10 positive was highest in 0-year old children as 3.7% (34/914) . The highest positive rate of diagnosed coxsackievirus A4 positive cases was admitted in April(2.6%, 12/460) , and the highest positive rate of diagnosed coxsackievirus A10 positive cases was admitted in August 4.3% (12/278). Phylogenetic analysis indicated that all the CoxA4 stains were divided into subtype A and subtype B, and the CoxA10 stains were divided into subtypes A, subtype B and subtype C. The VP1 gene nucleotide sequences of CoxA4 and CoxA10 this study measured both belonged to subtype A.</p><p><b>CONCLUSIONS</b>The VP1 gene nucleotide sequences of CoxA4 and CoxA10 in Guangzhou from 2010 to 2012 both belonged to subtype A.</p>