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Objective@#To identify the etiology and source of infection in a diarrhea outbreak in Yunnan in May 2017 and to provide the evidence for formulating prevention and control measures.@*Methods@#Epidemiological investigation was carried out on the epidemic situation of diarrhea in the village of Lvchun County in Yunnan Province, the field sampling, laboratory testing and data analysis were also performed.@*Results@#Among the 44 patients, 11 of the 13 samples were positive for rotavirus nucleic acid in group A, and the positive rate was 84.62%. The survey showed that the water supply pipe was damaged and polluted by human and livestock manure and domestic sewage. The trend of the damaged water pipe was basically the same as the case distribution, and the rainfall was significantly related to the number of the disease.@*Conclusions@#This event was an outbreak of diarrhea caused by group A rotavirus. The direct pollution of drinking water caused by rainfall may be the risk factor of this outbreak. The health management of rural drinking water should be strengthened and the health knowledge and education of preventing intestinal infectious diseases should be promoted.
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Objective@#To detect the enterovirus VP4 and VP1 genes in 510 stool samples collected from hand, foot and mouth disease (HFMD) cases and analyze the phylogenetic characteristics of the entire VP1 genes of coxsackievirus A6 (CV-A6) strains in six prefectures/cities of Yunnan Province in 2018.@*Methods@#Viral RNA was abstracted from the stool samples. VP4 gene sequences were amplified by RT-PCR and sequenced using the MD91/OL68-1 primer pair to identify viral genotypes. Whole VP1 gene sequences were amplified and sequenced using appropriate primer pairs. The whole VP1 gene sequences of CV-A6 reference strains were downloaded from GenBank. MEGA5.2 software was used to analyze the similarity in nucleotide and amino acid sequences between different strains and phylogenetic tree was constructed for analysis of genetic characteristics and molecular epidemiology.@*Results@#VP4 and VP1 gene sequences were obtained from 57 out of 510 stool samples with a positive rate of 11.17% (57/510). There were 43 CV-A6 (8.43%, 43/510), six CV-A10 (1.17%, 6/510), two enterovirus A71 (EV-A71, 0.39%, 2/510) and two CV-A9 (0.39%, 2/510) strains. The other four strains were CV-A4 (0.19%, 1/510), CV-A5 (0.19%, 1/510), CV-B1 (0.19%, 1/510) and E11 (0.19%, 1/510). The phylogenetic analysis showed that all 43 CV-A6 strains belonged to sub-genotype D3.@*Conclusions@#In the 510 HFMD samples, CV-A6 strains were mostly detected with a detection rate of 8.43% and accounted for 75.44% (43/57) of all isolates, followed by CV-A10 (1.17%, 6/510) and EV-A71 (0.39%, 2/510). There was a large HFMD outbreak mainly caused by CV-A6 in Yunnan Province in 2018. The outbreak was caused by CV-A6 of sub-genotype D3, as was the case with pervious outbreaks in China.
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Objective To detect the enterovirus VP4 and VP1 genes in 510 stool samples collect-ed from hand, foot and mouth disease ( HFMD) cases and analyze the phylogenetic characteristics of the en-tire VP1 genes of coxsackievirus A6 (CV-A6) strains in six prefectures/cities of Yunnan Province in 2018. Methods Viral RNA was abstracted from the stool samples. VP4 gene sequences were amplified by RT-PCR and sequenced using the MD91/OL68-1 primer pair to identify viral genotypes. Whole VP1 gene se-quences were amplified and sequenced using appropriate primer pairs. The whole VP1 gene sequences of CV-A6 reference strains were downloaded from GenBank. MEGA5. 2 software was used to analyze the simi-larity in nucleotide and amino acid sequences between different strains and phylogenetic tree was constructed for analysis of genetic characteristics and molecular epidemiology. Results VP4 and VP1 gene sequences were obtained from 57 out of 510 stool samples with a positive rate of 11. 17％ (57/510). There were 43 CV-A6 (8. 43％, 43/510), six CV-A10 (1. 17％, 6/510), two enterovirus A71 (EV-A71, 0. 39％, 2/510) and two CV-A9 (0. 39％, 2/510) strains. The other four strains were CV-A4 (0. 19％, 1/510), CV-A5 (0. 19％, 1/510), CV-B1 (0. 19％, 1/510) and E11 (0. 19％, 1/510). The phylogenetic analy-sis showed that all 43 CV-A6 strains belonged to sub-genotype D3. Conclusions In the 510 HFMD sam-ples, CV-A6 strains were mostly detected with a detection rate of 8. 43％ and accounted for 75. 44％ (43/57) of all isolates, followed by CV-A10 (1. 17％, 6/510) and EV-A71 (0. 39％, 2/510). There was a large HFMD outbreak mainly caused by CV-A6 in Yunnan Province in 2018. The outbreak was caused by CV-A6 of sub-genotype D3, as was the case with pervious outbreaks in China.
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Objective To analyze the genetic characteristics of VP1 3'region of human coxsack-ievirus B2 (CV-B2) strains isolated from Yunnan province. Methods RT-PCR and gene sequencing were performed to analyze the VP1 3'region of 15 CV-B2 strains isolated from acute flaccid paralysis ( AFP) cases during 2005 to 2006, healthy children in 2013 and hand, foot and mouth disease (HFMD) cases in 2014 in Yunnan province. CV-B2 VP1 gene reference sequences were downloaded from the Genbank. Nucleotide (nt) and amino acid (aa) diversities were calculated by MEGA5. 2 software and a phylogenetic tree was constructed. Genetic and molecular epidemiological characteristics of CV-B2 strains circulating in Yunnan province were analyzed. Results A total of 15 CV-B2 strains were isolated, which were one from 232 AFP cases in 2005, one from 240 AFP cases in 2006, 12 from 400 healthy children in 2013 and one from 500 HFMD cases in 2014. Phylogenetic analysis of the 15 CV-B2 strains in Yunnan province and those down-loaded from the GenBank showed that CV-B2 could be genetically divided into five genotypes. The prototype strain Ohio-1 and one strain (01-1) isolated in Taiwan in 1988 belonged to genotype 1. Strains isolated in France in 2006, 2007 and 2010 belonged to genotype 2. Strains isolated in Yunnan, Shandong, Henan, Fu-jian and Taiwan belonged to genotype 3. Strains isolated in Russia, Yunnan AFP cases in 2005 and 2006 and India belonged to genotype 4. Strains isolated in Taiwan, Shandong and New South Wales, Australia be-longed to genotype 5. Different genotypes distributed in different countries/areas with some confined within specific countries/areas. Conclusions The 12 strains isolated from healthy children and one from HFMD cases in Yunnan province belonged to genotype 3, while the two strains isolated from AFP cases belonged to genotype 4. Diversities in nt and aa sequences between the strains isolated from the healthy children and HFMD case were only 0. 76％ and 0. 03％, respectively, indicating that they might come from the same transmission source. However, the nt and aa diversities between the isolates of genotype 3 ( from healthy children and HFMD case) and genotype 4 (from AFP cases in 2005 and 2006) were 15. 11％-15. 22％ and 2. 76％-2. 72％, respectively. Correlation of CV-B2 with AFP and HFMD was worthy of further study.
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Objective To understand the viral etiology of acute respiratory infection in Kunming area. Methods We collected the nasopharyngeal swab of patients with acute respiratory tract infection,and used multiple reverse transcription-polymerase chain reaction (RT-PCR) method to detect 15 kinds of respiratory viral pathogens. Results Among the 600 samples,144 strains of viruses were detected, the positive rate was 24%,among which the highest positive rate was RSV (49/600,8.2%),followed by PIV (32/600,5.3%) HRV (27/600,4.5%) and IFV27 (27/600,4.5%) . The respiratory virus infection situation was different in every age group, groups of the highest virus positive rate was ≤1 age group (72/216, 33.3%);The respiratory virus infection situation in different seasons was different, the virus positive rate of the first quarter was the highest (85/144, 59%) . Conclusion RSV was the main virus pathogen of acute respiratory tract infections in Kunming area in 2011 years, the detection rate in sick children was the highest among all patients;the detection rate in the first quarter was higher than other quarters.