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Guo R.-N.,U.S. Center for Disease Control and Prevention | Zheng H.-Z.,Institute of Immunization Programs | Ou C.-Q.,Southern Medical University | Huang L.-Q.,U.S. Center for Disease Control and Prevention | And 7 more authors.
PLoS ONE | Year: 2016

Background The disease burden associated with influenza in developing tropical and subtropical countries is poorly understood owing to the lack of a comprehensive disease surveillance system and information-exchange mechanisms. The impact of influenza on outpatient visits, hospital admissions, and deaths has not been fully demonstrated to date in south China. Methods A time series Poisson generalized additive model was used to quantitatively assess influenza- like illness(ILI) and influenza disease burden by using influenza surveillance data in Zhuhai City from 2007 to 2009, combined with the outpatient, inpatient, and respiratory disease mortality data of the same period. Results The influenza activity in Zhuhai City demonstrated a typical subtropical seasonal pattern; however, each influenza virus subtype showed a specific transmission variation. The weekly ILI case number and virus isolation rate had a very close positive correlation(r = 0.774, P < 0.0001). The impact of ILI and influenza on weekly outpatient visits was statistically significant(P < 0.05). We determined that 10.7% of outpatient visits were associated with ILI and 1.88%were associated with influenza. ILI also had a significant influence on the hospitalization rates(P < 0.05), but mainly in populations <25 years of age. No statistically significant effect of influenza on hospital admissions was found(P > 0.05). The impact of ILI on chronic obstructive pulmonary disease(COPD) was most significant(P < 0.05), with 33.1% of COPD-related deaths being attributable to ILI. The impact of influenza on the mortality rate requires further evaluation. Conclusions ILI is a feasible indicator of influenza activity. Both ILI and influenza have a large impact on outpatient visits. Although ILI affects the number of hospital admissions and deaths, we found no consistent influence of influenza, which requires further assessment. © 2016 Chen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

He D.M.,Institute of Pathogenic Microorganisms
Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi | Year: 2011

To understand the phenotypic characteristics of foodborne Vibrio parahaemolyticus in Guangdong province through carrying out a comprehensive comparison including pulse field gel electrophoresis, ribotyping and serotyping. 74 different Vibrio parahaemolyticus strains isolated from seafood and cases due to food poisoning in Guangdong province were under serotyping and susceptibility testing, in addition to the testing of direct heat hemolysin (tdh) and the heat hemolysin-related hemolysin hormone (trh) via PCR. Ribosomal genotyping (ribotyping) with EcoR I restriction enzyme was utilized on 74 different Vibrio parahaemolyticus isolates, whereas pulsed-field gel electrophoresis (PFGE) with the Not I restriction enzyme was used on 74 different Vibrio parahaemolyticus isolates. BioNumerics software was used to compare the isolates from different sources, times and places in order to elicit the correlation between different strains. Although Vibrio parahaemolyticus was 100.00% sensitive to chloramphenicol, it still presented different levels of resistance against 13 other antibiotics. Among the 74 different strains of Vibrio parahaemolyticus under testing, 24.32% showed positive for the tdh virulence gene, whereas 4.05% positive for trh. 74 different Vibrio parahaemolyticus strains were found to belong to 26 serotypes, where the O5:K17 and O2:K28 serotypes were dominant in those isolates that causing seafood-poisoning. The O3:K6 serotype was found to be the dominant of those isolates that causing food-poisoning. Based on ribosomal genotyping, the 74 Vibrio parahaemolyticus isolates were divided into 62 different ribotypes, whereas the 74 strains of Vibrio parahaemolyticus were divided into 67 different PFGE types, thus exhibiting considerable genetic diversities of the strains. Majority of the isolates causing food-poisoning carried tdh virulence gene. PFGE was shown to have the highest resolution, followed by ribotyping with serotyping being the lowest, where the combination of the three could improve the resolution.

He D.M.,Institute of Pathogenic Microorganisms
Zhonghua yu fang yi xue za zhi [Chinese journal of preventive medicine] | Year: 2012

In order to better understand the nature of Salmonella infection in diarrheal patients in Guangdong province, the study analyzed the serum types, antibiotic resistance and molecular determinants of the isolated Salmonella strains. In year 2010, 8405 diarrhea patients from 16 surveillant hospital in Guangzhou, Zhongshan, Dongguan, Zhuhai, Maoming, Yangjiang and Jiangmen cities in Guangdong province, were recruited in the study. A total of 8405 fecal specimen were collected and subjected to Salmonella isolation and culture. The isolated Salmonella strains were further analyzed via serotyping, antimicrobial susceptibility testing, and PFGE. The χ(2) test was applied to compare the differences between the isolated Salmonella strains in different seasons and districts. BioNumerics software was used to analyze the PFGE results in order to determine the correlation between different Salmonella strains. The positive rate of the surveillant Salmonella in Guangdong province was 3.58% (301/8405) in 2010; with the gender ratio at 1.34:1 (166/124). Salmonella infection was found in all age groups, and most in infants, accounting for 57.48% (173/301). The isolated rates of Salmonella were separately 3.48% (61/1751), 4.97% (134/2695), 3.08% (73/2370) and 2.08% (33/1589) in the four seasons; and the difference was statistically significant (χ(2) = 27.29, P < 0.01). The isolated rates of Salmonella in different regions were as follows: Zhuhai 15.43% (25/162), Maoming 7.53% (18/239), Dongguan 6.51% (39/599), Yangjiang 3.64% (14/385), Zhongshan 3.03% (70/2309), Guangzhou 2.90% (126/4349) and Jiangmen 2.49% (9/362). The difference between regions was statistically significant (χ(2) = 100.75, P < 0.01). Except one strain of the isolated Salmonella cannot be serotyped, the other 300 strains were divided into 42 serotypes, of which Salmonella typhimurium and Salmonella enteritidis were dominant, account for 45.18% (136/301) and 10.96% (33/301) respectively. Although over 85% of Salmonella were sensitive to cephalosporin, ACSSuT resistance patterns (defined as resistance to at least ampicillin, chloramphenicol, streptomycin, sulfamethoxazole and tetracycline) reached 34.88% (105/301), the highest resistant rate was found in serotype Salmonella typhimurium, as high as 65.44% (89/136). 136 strains of Salmonella typhimurium were divided into 51 PFGE types, showed great genetic diversity. 33 strains of Salmonella enteritidis were divided into 18 PFGE types. The strains with same PFGE pattern may have different drug-resistant patterns, and vice versa. Salmonella typhimurium and Salmonella enteritidis were the dominant serotypes causing infectious diarrhea in Guangdong province. Cephalosporin was the primary choice in clinical medicine. However, Salmonella typhimurium was resistant to drug most seriously in Guangdong province. There was no significant correlation between Salmonella resistance patterns and PFGE type.

Guo R.-n.,Institute of Infectious Disease Prevention and Control | Zheng H.-z.,Institute of Infectious Disease Prevention and Control | Huang L.-q.,U.S. Center for Disease Control and Prevention | Zhou Y.,U.S. Center for Disease Control and Prevention | And 5 more authors.
PLoS ONE | Year: 2012

Objectives: To understand the incidence of outpatient influenza cases in a subtropical area of China and the associated economic burden on patients' families. Methods: A hospital-based prospective study was conducted in Zhuhai City during 2008-2009. All outpatient influenza-like illness (ILI) cases were identified in 28 sentinel hospitals. A representative sample of throat swabs from ILI cases were collected for virus isolation using Madin-Darby canine kidney cells. The incidence of outpatient influenza cases in Zhuhai was estimated on the basis of the number of influenza patients detected by the sentinel sites. A telephone survey on the direct costs associated with illness was conducted as a follow-up. Results: The incidence of influenza was estimated to be 4.1 per 1,000 population in 2008 and 19.2 per 1,000 population in 2009. Children aged <5 years were the most-affected population, suffering from influenza at the highest rates (34.3 per 1,000 population in 2008 and 95.3 per 1,000 population in 2009). A high incidence of 29.2-40.9 per 1000 population was also seen in young people aged 5-24 years in 2009. ILI activity and influenza virus isolations adopted a consistent seasonal pattern, with a summer peak in July 2008 and the longest epidemic period lasting from July-December 2009. The medical costs per episode of influenza among urban patients were higher than those for rural patients. A total of $1.1 million in direct economic losses were estimated to be associated with outpatient influenza during 2008-2009 in Zhuhai community. Conclusions: Influenza attacks children aged <5 years in greater proportions than children in other age groups. Seasonal influenza 2008 and Pandemic influenza A (H1N1) 2009 had different epidemiological and etiological characteristics. Direct costs (mostly medical costs) impose an enormous burden on the patient family. Vaccination strategies for high-risk groups need to be further strengthened. © 2012 GUO et al.

Li B.S.,Institute of Pathogenic Microorganisms
Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi | Year: 2011

To understand the distribution, molecular characteristics and virulence genes of the O1 and O139 Vibrio cholerae isolates from the Pearl River Estuary water. Vibrio cholerae isolates collected from the Pearl River estuary waters from January 2009 to December 2010, were tested by PCR for eight virulence-related genes, including cholera toxin (ctxA), zonula occludens toxin (zot), accessory cholera enterotoxin (ace), hemolysin (hlyA), toxin-coregulated pilus (tcpA), outer membrane protein (ompU), and the regulatory protein genes (tcpI, toxR). Genetic relation was assessed by pulsed-field gel electrophoresis (PFGE) and the patterns were clustered by BioNumerics. From 1152 aquatic samples, 69 isolates were identified, including 41 Inaba, 18 Ogawa and 10 O139. All the isolates showed ctxA negative, while the hlyA and toxR genes were positive in all the isolates. 34.15% (14/41) of the Inaba strains were hlyA(+) toxR(+) ompU(+) ace(+) zot(+) tcpI(+), while 66.67% (12/18) belonged to Ogawa strains and 70% (7/10) of the O139 strains were hlyA(+) toxR(+). Through PFGE analysis, the O1 isolates formed three clusters in this study. The patterns of O1 isolates differed widely, with the similarity as 72.8% - 100.0%, while the patterns of O139 isolates having the similarity of 69.9% - 95.5%. The non-toxigenic O1 and O139 V. cholerae had a wide distribution in the environment of Pearl River estuary water during the non-epidemic period of cholera. All the aquatic isolates presented diversities on the related virulent genes.

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