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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.

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.

Guo R.-N.,U.S. Center for Disease Control and Prevention | Lin J.-Y.,U.S. Center for Disease Control and Prevention | Li L.-H.,U.S. Center for Disease Control and Prevention | Ke C.-W.,Institute of Pathogenic Microorganisms | And 6 more authors.
PLoS ONE | Year: 2014

Objectives: Frequent outbreaks of dengue are considered to be associated with an increased risk for endemicity of the disease. The occurrence of a large number of indigenous dengue cases in consecutive years indicates the possibility of a changing dengue epidemic pattern in Guangdong, China. Methods: To have a clear understanding of the current dengue epidemic, a retrospective study of epidemiological profile, serological response, and virological features of dengue infections from 2005-2011 was conducted. Case data were collected from the National Notifiable Infectious Diseases Reporting Network. Serum samples were collected and prepared for serological verification and etiological confirmation. Incidence, temporal and spatial distribution, and the clinical manifestation of dengue infections were analyzed. Pearson's Chi-Square test was used to compare incidences between different age groups. A seroprevalence survey was implemented in local healthy inhabitants to obtain the overall positive rate for the specific immunoglobulin (Ig) G antibody against dengue virus (DENV). Results: The overall annual incidence rate was 1.87/100000. A significant difference was found in age-specific incidence (Pearson's Chi-Square value 498.008, P<0.001). Children under 5 years of age had the lowest incidence of 0.28/100000. The vast majority of cases presented with a mild manifestation typical to dengue fever. The overall seroprevalence of dengue IgG antibody in local populations was 2.43% (range 0.28%-5.42%). DENV-1 was the predominant serotype in circulation through the years, while all 4 serotypes were identified in indigenous patients from different outbreak localities since 2009. Conclusions: A gradual change in the epidemic pattern of dengue infection has been observed in recent years in Guangdong. With the endemic nature of dengue infections, the transition from a monotypic to a multitypic circulation of dengue virus in the last several years will have an important bearing on the prevention and control of dengue in the province and in the neighboring districts. © 2014 Guo et al.

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