Tiegang Li

Food markets with live birds as source of avian influenza.

A patient may have been infected with highly pathogenic avian influenza virus H5N1 in Guangzhou, Peoples Republic of China, at a food market that had live birds. Virus genes were detected in 1 of 79 wire cages for birds at 9 markets. One of 110 persons in the poultry business at markets had neutralizing antibody against H5N1.

Antibody dynamics of 2009 influenza A (H1N1) virus in infected patients and vaccinated people in China.

Background To evaluate the risk of the recurrence and the efficiency of the vaccination, we followed-up antibody responses in patients with the 2009 pandemic H1N1 influenza and persons who received the pandemic H1N1 vaccine in Guangzhou China. Methods We collected serum samples from 129 patients and 86 vaccinated persons at day 0, 15, 30, 180 after the disease onset or the vaccination, respectively. Antibody titers in these serum samples were determined by haemagglutination inhibition (HI) assay using a local isolated virus strain A/Guangdong Liwan/SWL1538/2009(H1N1). Results HI antibody positive rate of the patients increased significantly from 0% to 60% at day 15 (χ2 = 78, P<0.001) and 100% at day 30 (χ2 = 23, P<0.001), but decreased significantly to 52% at day 180 (χ2 = 38, P<0.001), while that of vaccinated subjects increased from 0% to 78% at day 15 (χ2 = 110, P<0.001) and 81% at day 30 (χ2 = 0.32, P = 0.57), but decreased significantly to 34% at day 180 (χ2 = 39, P<0.001). Geometric mean titers (GMT) of HI antibodies in positive samples from the patients did not change significantly between day 15 and day 30 (T = 0.92, P = 0.36), but it decreased significantly from 80 at day 30 to 52 at day 180 (T = 4.5, P<0.001). GMT of vaccinated persons increased significantly from 100 at day 15 to 193 at day 30 (T = 4.5, P<0.001), but deceased significantly to 74 at day 180 (T = 5.1, P<0.001). Compared to the patients, the vaccinated subjects showed lower seroconversion rate (χ2 = 11, P<0.001; χ2 = 5.9, P = 0.015), but higher GMT (T = 6.0, P<0.001; T = 3.6, P = 0.001) at day 30 and day 180, respectively. Conclusion Vaccination of 2009 influenza A (H1N1) was effective. However, about half or more recovered patients and vaccinated persons might have lost sufficient immunity against the recurrence of the viral infection after half a year. Vaccination or re-vaccination may be necessary for prevention of the recurrence.

Temperature, relative humidity and sunshine may be the effective predictors for occurrence of malaria in Guangzhou, southern China, 2006-2012

Malaria has been endemic in Guangzhou for more than 50 years. The goal of this study was to use a negative binomial regression to identify the relationship between meteorological variables and malaria reported. Our results revealed that each 1°C rise of temperature corresponds to an increase of 0.90% in the monthly number of malaria cases. Likewise, a one percent rise in relative humidity led to an increase of 3.99% and a one hour rise in sunshine led to an increase of 0.68% in the monthly number of cases. Our findings may be useful for developing a simple, precise malaria early warning system.

Mycobacterium abscessus post-injection abscesses from extrinsic contamination of multiple-dose bottles of normal saline in a rural clinic.

BACKGROUND We investigated an outbreak of gluteal abscesses following intramuscular (IM) injections given at a clinic in rural China to identify the causative agent, source, and method of exposure. METHODS We defined a case as an abscess that appeared at the site of an injection given since June 1, 2006. We compared case rates by injection route, medication, and diluents. We reviewed injection practices, and cultured abscesses and environmental sites for mycobacteria. RESULTS From October through December 2006, 5.8% (n=35) of 604 persons who had received injections at the clinic developed a case. All 35 cases occurred in 184 patients (attack rate=19.0%) who had received IM injections with various drugs that had been mixed with normal saline (NS); risk ratio=infinity; p<0.0001. No cases occurred in the absence of NS exposure. We identified Mycobacterium abscessus from eight abscesses and from the clinic water supply, and observed the inappropriate reuse of a 16-gauge needle left in the rubber septum of 100 ml multiple-dose bottles of NS in the clinic. Fourteen percent (n=527) of the 3887 registered residents of this village had been treated with IM drugs over a three-month period, often for minor illnesses. CONCLUSIONS This outbreak of M. abscessus occurred from exposure to extrinsically contaminated NS through improper injection practices. Frequent treatment of minor illnesses with IM injections of antibiotics was likely an important contributing factor to the size of this outbreak.

Epidemiological investigation of an outbreak of pandemic influenza A (H1N1) 2009 in a boarding school: Serological analysis of 1570 cases

BACKGROUND A large number of 2009 pandemic influenza A (H1N1) infections were localized in school populations. OBJECTIVES To describe the epidemiology, clinical features and risk factors associated with an outbreak that occurred at a vocational boarding school in Guangzhou, P.R. China. STUDY DESIGN Data were collected prospectively and retrospectively through the use of on-site doctors and a post-outbreak survey and blood collection. The survey was used to confirm symptoms, and to investigate a series of flu-related factors such as dormitory conditions, health habits, vaccine history and population contact history. Blood samples were taken for serological analysis. Pandemic H1N1 infection was initially confirmed by a real-time RT-PCR assay. Following the identification of the outbreak by the Guangzhou CDC on September 4, cases were diagnosed symptomatically and retrospectively by serological analysis using the hemagglutination inhibition assay and a neutralization assay. RESULTS The infection rate was 32% (505/1570) and the attack rate was 22.2% (349/1570). The asymptomatic infection rate was 9.9% (156/1570). Sharing a classroom (OR=2.17, 95% CI: 1.62-2.91) and dormitory space (OR=2.32, 95% CI: 1.84-2.93) was associated with higher rates of infection. Opening windows for ventilation was the only control measure that significantly protected against infection. CONCLUSION Social isolation and quarantine should be used to prevent the spread of infection. Ventilation and a control of air flow between classrooms and dorms should be implemented as possible. School closures may be effective if implemented early.

HAND-FOOT-AND-MOUTH DISEASE EPIDEMIOLOGICAL STATUS AND RELATIONSHIP WITH METEOROLOGICAL VARIABLES IN GUANGZHOU, SOUTHERN CHINA, 2008-2012

Hand-foot-and-mouth disease (HFMD) is becoming one of the extremely common airborne and contact transmission diseases in Guangzhou, southern China, leading public health authorities to be concerned about its increased incidence. In this study, it was used an ecological study plus the negative binomial regression to identify the epidemic status of HFMD and its relationship with meteorological variables. During 2008-2012, a total of 173,524 HFMD confirmed cases were reported, 12 cases of death, yielding a fatality rate of 0.69 per 10,000. The annual incidence rates from 2008 to 2012 were 60.56, 132.44, 311.40, 402.76, and 468.59 (per 100,000), respectively, showing a rapid increasing trend. Each 1 °C rise in temperature corresponded to an increase of 9.47% (95% CI 9.36% to 9.58%) in the weekly number of HFMD cases, while a one hPa rise in atmospheric pressure corresponded to a decrease in the number of cases by 7.53% (95% CI -7.60% to -7.45%). Similarly, each one percent rise in relative humidity corresponded to an increase of 1.48% or 3.3%, and a one meter per hour rise in wind speed corresponded to an increase of 2.18% or 4.57%, in the weekly number of HFMD cases, depending on the variables considered in the model. These findings revealed that epidemic status of HFMD in Guangzhou is characterized by high morbidity but low fatality. Weather factors had a significant influence on the incidence of HFMD.

Dengue Fever Epidemiological Status and Relationship with Meteorological Variables in Guangzhou, Southern China, 2007–2012

Ecological methodology plus negative binomial regression were used to identify dengue fever (DF) epidemiological status and its relationship with meteorological variables. From 2007 to 2012, annual incidence rate of DF in Guangzhou was 0.33, 0.11, 0.15, 0.64, 0.45, and 1.34 (per 100 00) respectively, showing an increasing trend. Each 1° C rise of temperature corresponded to an increase of 10.23% (95% Cl 7.68% to 12.83%) in the monthly number of DF cases, whereas 1 hPa rise of atmospheric pressure corresponded to a decrease in the number of cases by 5.14% (95% Cl: 7.10%-3.14%). Likewise, each one meter per second rise in wind velocity led to an increase by 43.80% or 107.53%, and one percent rise of relative humidity led to an increase by 2.04% or 2.19%.

A Two-Year Surveillance of 2009 Pandemic Influenza A (H1N1) in Guangzhou, China: From Pandemic to Seasonal Influenza?

In this two-years surveillance of 2009 pandemic influenza A (H1N1) (pH1N1) in Guangzhou, China, we reported here that the scale and duration of pH1N1 outbreaks, severe disease and fatality rates of pH1N1 patients were significantly lower or shorter in the second epidemic year (May 2010-April 2011) than those in the first epidemic year (May 2009-April 2010) (P<0.05), but similar to those of seasonal influenza (P>0.05). Similar to seasonal influenza, pre-existing chronic pulmonary diseases was a risk factor associated with fatal cases of pH1N1 influenza. Different from seasonal influenza, which occurred in spring/summer seasons annually, pH1N1 influenza mainly occurred in autumn/winter seasons in the first epidemic year, but prolonged to winter/spring season in the second epidemic year. The information suggests a tendency that the epidemics of pH1N1 influenza may probably further shift to spring/summer seasons and become a predominant subtype of seasonal influenza in coming years in Guangzhou, China.

Correlation between clonorchiasis incidences and climatic factors in Guangzhou, China

BackgroundHuman infection with Clonorchis sinensis is still a big public health problem in Guangzhou. To investigate the correlation between clonorchiasis and climatic factors, we analyzed the clonorchiasis reported cases and simultaneous meteorological data during 2006–2012 in Guangzhou City, China.FindingsAnnual incidence rate of clonorchiasis from 2006 to 2012 was 166.76, 191.55, 247.37, 213.82, 246.03, 274.71, and 239.63 (per 100 000), respectively. Each 1°C rise of temperature corresponded to an increase of 1.18% (95% CI 0.88% to 1.48%) in the monthly number of cases, and a one millimeter rise of rainfall corresponded to increase of 0.03% (95% CI 0.01% to 0.04%). Whereas each one percent rise of relative humidity corresponded to a decrease in the number of cases by 1.51% (95% CI -1.75% to -1.27%).ConclusionsWe reported incidence rates of clonorchiasis showed an increasing trend by years. Temperature and rainfall were positively associated with clonorchiasis incidence, while relative humidity was inversely associated with clonorchiasis incidence. Our study provided evidence that climatic factors affect the occurrence of clonorchiasis in Guangzhou city, China.

Attitudes, practices and information needs regarding novel influenza A (H7N9) among employees of food production and operation in Guangzhou, Southern China: a cross-sectional study

BackgroundAs of 30 May 2013, 132 human infections with avian influenza A (H7N9) had been reported in 10 Chinese cities. On 17 May 2013, because a chicken infection with H7 subtype avian influenza virus was detected in Guanzhou, Guangzhou became the 11th city to conduct emergency response operations. The goal of this study was to identify attitudes, practices and information needs among employees of food production and operation in Guangzhou.MethodsA cross-sectional survey of face-to-face interviews was used during 17–24 June 2013. All adults seeking health examination in Guangzhou Center for Disease Control and Prevention who had lived in Guangzhou for at least 3 months, were engaged in food production and operation, and agreed to participate were interviewed.ResultsOf 1,450 participants, 69.72% worried about being infected with the A/H7N9 and 74.41% stated that they had searched for information about A/H7N9. The internet (76.92%), television (67.56%), and newspapers (56.26%) were the main methods of obtaining information; the use of these methods differed significantly by various demographic variables (P < 0.05). More than one-fifth of participants complained that the information was not timely enough (20.28%) and was intentionally concealed by the government (20.76%). Nearly one-third (32.35%) did not believe that the government could control the A/H7N9 epidemic. Most participants (80.76%) reported washing hands more frequently than before, while over one-third (37.17%) stated no longer buying poultry. A total of 84.00% indicated a willingness to receive an A/H7N9 vaccine, and the primary reason for not being willing was concern about safety (58.19%). A history of influenza vaccination and worry about being infected with the A/H7N9 were significantly associated with intention to receive an A/H7N9 vaccine (P < 0.05).ConclusionsOur findings provide insight into the attitudes and practices of employees of food production and operation 3 months after the first human A/H7N9 case reported in China, and 1 month after infected chickens were identified in Guangzhou. Distrust in the health department should be addressed, and more effort should be made to improve compliance of proper preventive measures to reduce panic among the public. The information needs should be taken into account in the next step of health education.