Characterizing a large outbreak of dengue fever in Guangdong Province, China.

BACKGROUND: Dengue cases have been reported each year for the past 25 years in Guangdong Province, China with a recorded historical peak in 2014. This study aims to describe the epidemiological characteristics of this large outbreak in order to better understand its epidemic factors and to inform control strategies. METHODS: Data for clinically diagnosed and laboratory-confirmed dengue fever cases in 2014 were extracted from the China Notifiable Infectious Disease Reporting System. We analyzed the incidence and characteristics of imported and indigenous cases in terms of population, temporal and spatial distributions. RESULTS: A total of 45 224 dengue fever cases and 6 deaths were notified in Guangdong Province in 2014, with an incidence of 47.3 per 100 000 people. The elderly (65+ years) represented 11.7 % of total indigenous cases with the highest incidence (72.3 per 100 000). Household workers and the unemployed accounted for 23.1 % of indigenous cases. The majority of indigenous cases occurred in the 37(th) to 44(th) week of 2014 (September and October) and almost all (20 of 21) prefecture-level cities in Guangdong were affected. Compared to the non-Pearl River Delta Region, the Pearl River Delta Region accounted for the majority of dengue cases and reported cases earlier in 2014. Dengue virus serotypes 1 (DENV-1), 2 (DENV-2) and 3 (DENV-3) were detected and DENV-1 was predominant (88.4 %). CONCLUSIONS: Dengue fever is a serious public health problem and is emerging as a continuous threat in Guangdong Province. There is an urgent need to enhance dengue surveillance and control, especially for the high-risk populations in high-risk areas.

Molecular Detection and Phylogenetic Characterization of Bat and Human Adenoviruses in Southern China.

Several novel adenoviruses (AdVs) have recently been identified in humans and other animal species. In this study, we report the molecular detection of and phylogenetically characterize bat and human AdVs detected in fecal or rectal swab samples collected in southern China. To detect AdVs, a 252-261 bp fragment of the DNA polymerase (DPOL) gene was amplified using nested PCR. A total of 520 rectal swab samples were collected from eight bat species in four geographic regions of southern China (Guangzhou, Yunfu, Huizhou, and Haikou city). Thirty-six (6.9%) samples from the following species tested positive for AdVs: Myotis ricketti, Miniopterus schreibersii, Scotophilus kuhlii, Taphozous melanopogon, Rhinolophus blythi, and Cynopterus sphinx. Eight novel AdVs were detected in 13.3% of the samples from C. sphinx. Of 328 fecal samples from patients with diarrhea, 16 (4.9%) were positive for classical human AdVs. Phylogenetic analysis showed that human AdVs shared low similarity (57.1-69.3%) with bat AdVs in deduced amino acid sequences of the AdV DPOL region. Thus, our study indicated that bat AdVs and human AdVs are species specific. As such, there is no evidence of cross-species transmission of AdV between bats and humans based on current data.

High prevalence and diversity of viruses of the subfamily Gammaherpesvirinae, family Herpesviridae, in fecal specimens from bats of different species in southern China.

Several studies have reported the detection of herpesviruses (HVs) in bats. However, the prevalence and phylogenetic characteristics of HVs in bats are still poorly understood. To elucidate the epidemiological characteristics of bat HVs in southern China, 520 fecal samples from eight bat species were collected in four geographic regions of southern China. Of these samples, 73 (14.0 %) tested positive for HVs using nested polymerase chain reaction assay. Phylogenetic analysis revealed a high degree of molecular diversity of HVs in bats of different species from different geographic regions. Our study provides evidence for co-evolution of bats and HVs.

Health impact of the 2008 cold spell on mortality in subtropical China: the climate and health impact national assessment study (CHINAs).

BACKGROUND: Many studies have investigated heat wave related mortality, but less attention has been given to the health effects of cold spells in the context of global warming. The 2008 cold spell in China provided a unique opportunity to estimate the effects of the 2008 cold spell on mortality in subtropical regions, spatial heterogeneity of the effects, stratification effect and added effects caused by sustained cold days. METHODS: Thirty-six study communities were selected from 15 provinces in subtropical China. Daily mortality and meteorological data were collected for each community from 2006 to 2010. A distributed lag linear non-linear model (DLNM) with a lag structure of up to 27 days was used to analyze the association between the 2008 cold spell and mortality. Multivariate meta-analyses were used to combine the cold effects across each community. RESULTS: The 2008 cold spell increased mortality by 43.8% (95% CI: 34.8% ~ 53.4%) compared to non-cold spell days with the highest effects in southern and central China. The effects were more pronounced for respiratory mortality (RESP) than for cardiovascular (CVD) or cerebrovascular mortality (CBD), for females more than for males, and for the elderly aged ≥75 years old more than for younger people. Overall, 148,279 excess deaths were attributable to the 2008 cold spell. The cold effect was mainly from extreme low temperatures rather than sustained cold days during this 2008 cold spell. CONCLUSIONS: The 2008 cold spell increased mortality in subtropical China, which was mainly attributable to the low temperature rather than the sustained duration of the cold spell. The cold effects were spatially heterogeneous and modified by individual-specific characteristics such as gender and age.

[Relationship between temperature and the risks of mortality in China: a Meta-analysis].

OBJECTIVE: To understand the effect of temperature on the risk of mortality and the modification effect of latitude, in China. METHODS: Relevant papers were searched and Meta-analysis was used to determine the exposure-response relationship for each health outcome which was associated with the exposure to temperature. Meta-regression analysis was used to evaluate the effect modification by latitude. RESULTS: Ten studies in 15 cities were included in the study. When temperature increased by one centigrade, the risks of mortality showed the following changes:deaths from non-accidental increased by 2% (95%CI:1%, 3%), from cardiovascular disease increased by 4% (95%CI:2%, 6%)and from the respiratory disease increased by 2% (95%CI:1%, 4%). As temperature decreased by one centigrade, the mortality risks of the following diseases showed the changes as: non-accidental death increased by 4% (95% CI:2%, 7%), cardiovascular disease increased by 4% (95%CI:1%, 7%)and the respiratory diseases increased by 2% (95%CI:0%, 4%). When latitude ranged from 0 to 25, 26 to 30, 31 to 39 degree or over 40 degrees, respectively and the temperature decreased by one centigrade, the mortality risks of the general population increased by 6.5% (95%CI:-2.7%, 15.6%), 5.8% (95% CI:2.4%, 9.3%),0.8% (95%CI:0.4%, 1.2%),0.5% (95%CI: -0.5%, 1.5%). As temperature increased by one centigrade, mortality risk of the general population increased by 0.6% (95%CI:-0.3%, 1.4%), 1.9% (95%CI:0.7%, 3.1%), 2.0% (95%CI:1.0%, 3.0%) and 5.8% (95% CI:-3.2%, 14.8%). As latitude increased by five degrees with high temperature, the mortality risk of general people increased by 0.3% (95% CI:0.1% ,0.8%) while decreased by 0.8% (95% CI:0.5%, 0.9%) under low temperature. CONCLUSION: In China, the mortality risk increased along with the changes of temperature. The adaptability to coldness among people living in high latitude areas seemed to be stronger than those living in other areas of latitudes. Who were more vulnerable to high temperature.

[The impact of temperature on cardiovascular disease deaths in 4 cities, China: a time-series study].

OBJECTIVE: To estimate the effects of temperature on cardiovascular disease (CVD) deaths in 4 cities-Kunming, Changsha, Guangzhou and Zhuhai, from southern part of China. METHODS: Daily CVD deaths, meteorological and air pollution data were used to explore the association between temperature and mortality. Distributed lag non-linear model was fitted for each city to access the delayed and cumulative effects of low, median and high temperature on CVD deaths. Cold and hot effects of temperature on CVD deaths were then accessed, based on the linear threshold model. RESULTS: The city-specific exposure-response functions appeared to be non-linear. Temperatures that associated with the lowest mortality for Changsha, Kunming, Guangzhou and Zhuhai were 22.0°C, 20.0°C, 26.0°C, and 25.5°C. The greatest cumulative RRs (95%CI) for CVD deaths of low temperature during the delayed period of the study in the 4 cities were 1.858 (1.089 - 3.170), 1.537 (1.306 - 1.809), 2.121 (1.771 - 2.540) and 1.934 (1.469 - 2.548), while 1.100 (0.816 - 1.483), 1.061 (0.956 - 1.177), 1.134 (1.047 - 1.230) and 1.259 (1.104 - 1.436) for high temperatures in Changsha, Kunming, Guangzhou and Zhuhai respectively. The hot effect was greater than the cold effect on the current days. The hot effect was restricted to the first week, whereas the cold effect increased over the lag days, and then last for 3 - 4 weeks. CONCLUSION: The city-specific exposure-response functions appeared to be non-linear. Both high and cold temperatures were associated with increased CVD deaths, but the impact of low temperature was more notable. Cold effect was delayed by several days but last for a longer period than the hot effect did.

[Time-series analysis on the malaria morbidity affected by meteorological factors in Guangdong province].

OBJECTIVE: To evaluate the associations between malaria risk and meteorological factors. METHODS: A negative binomial distribution regression analysis was built between the temperature, relative humidity, rainfall capacity and the monthly incidence of malaria, based on the temperature information provided by Guangdong Meteorological Department and the malaria incidence information provided by Guangdong Center of Disease Prevention and Control during year 1980 to 2004, adopting the time-series analysis method and by distributed lag non-linear model, in order to analyze the immediate factors. RESULTS: The number of monthly malaria cases in Guangdong province reached 4010 between year 1984 and 2004, while the monthly maximal temperature, minimal temperature, average temperature, relative humidity and average rainfall capacity was separately 26.3°C, 18.8°C, 21.9°C, 88.0% and 5.6 mm. The immediate effect of monthly maximal temperature on malaria incidence showed non-linear relationships. When the temperature reached 32.3°C, the risk was highest, the relative risk (RR) was 2.51 (95%CI: 1.99 - 3.16); when the relative humidity was 60.0%, the relative risk of malaria was highest as 1.19 (95%CI: 0.66 - 2.11) and then decreased gradually; and when the relative humidity was 86.6%, the risk of malaria was lowest at 0.51 (95%CI: 0.34 - 0.76). The risk of malaria increased while the rainfall capacity was 14.5 mm, the risk of malaria was the highest at 1.29 (95%CI: 0.87 - 1.93). Strongest delayed effects on malaria incidence was observed when the monthly maximal temperature reached 31.5°C at lagged 2 months, with the value of RR at 1.81 (95%CI: 1.02 - 3.22). When the monthly rainfall capacity was over 15.2 mm, the delayed effects was strong but short. When the monthly maximal temperature of 33.7°C, the excess risk of malaria was comparatively high, the excess risk was 92.2% (95%CI: 30.5% - 183.2%) when lagging one month. When the relative humidity was low, the delayed effect of malaria lasted for a long time, and the cumulative effect was huge. When the relative humidity reached 87.0%, the excess risk lagging 3 months was only -66.6% (95%CI: -86.4% - -17.7%). When the rainfall capacity was 15.5 mm, the cumulative effect on malaria reached the peak after 3 months, while the excess risk was 40.7% (95%CI: -30.0% - -182.6%); afterwards the cumulative effect gradually weakened. Positive and negative interaction effects were significant between malaria risk and maximal temperature and monthly rainfall capacity, and monthly rainfall capacity and relative humidity at lagged 2 months, respectively. CONCLUSION: High temperature and large rainfall capacity might be the risk factors of malaria in Guangdong province, and there was an obvious interaction between the two factors.

[What temperature index is the best predictor for the impact of temperature on mortality].

OBJECTIVE: To explore the suitable temperature index to establish temperature-mortality model. METHODS: The mortality and meteorological information of Guangzhou between year 2006 and 2010 were collected to explore the association between sendible temperature, heat index and deaths by adopting distributed lag non-linear model to fit the daily maximum, mean and minimum temperature with and without humidity. Q-Q plots based on the standardized residuals of each model were used to qualitatively access the goodness of fitting. The minimum Akaike information criterion (AIC) and residual sum of squares (RSS) value were used to explore the most suitable temperature index for model establishment, and to further analyze the fittest temperature index for different diseases, ages and cold and hot effect. RESULTS: Guangzhou features a subtropical monsoon climate, with an annual average temperature at 22.9°C and daily average relative humidity of 71%. The standardized residuals of all models followed normal distribution. For all death, death from circulation system diseases, the 65-84 years old aging groups and cold effect models, the daily average temperature fit better, whose AIC (RSS) values were the smallest as 11 537 (1897), 9527 (1928), 10 595 (2018) and 11 523 (1899), respectively. However, for death from respiratory system disease, groups aging under 65 years old or over 85 years old and hot effect models, the daily average sendible temperature fit better, whose AIC (RSS) values were the smallest as 8265(1854), 675 (1739), 8550 (1871) and 11 687 (1938), respectively. In comparison with the model controlling both temperature and relative humidity, different diseases, aging groups and cold and hot effect models fitted by sendible temperature index showed smaller AIC (RSS) values. The relative risk (RR) value of the cold effect lagging 0 - 3 days fitting by daily maximal temperature was < 1, and the RR value of it fitting by daily minimum temperature was > 1.04. The RR value of the hot effect lagging 0 - 1 days fitting by daily maximal temperature was < 1.16, and the RR values of it fitting by daily minimum temperature and daily average temperature were > 1.16. CONCLUSION: There were no best temperature indicators for different diseases, ages and cold and hot effect. The model using sendible temperature index better fit the model including relative humidity as a covariable.

[The assessment of vulnerability to floods in Guangdong province at district level].

OBJECTIVE: To evaluate the vulnerability to floods in Guangdong province at district level. METHODS: Data were collected from the sixth census, the 2010 Statistical Yearbook of Guangdong, the 2010 Health Statistics Yearbook of Guangdong and China Disease Prevention and Control information systems, etc. The weight of each indicator was determined based on subjective method and objective method respectively; and finally the results of the two methods were compared. RESULTS: 13 indicators were selected for the assessment of vulnerability to floods, including 6 sensitivity indicators, 5 adaptability indicators and 2 exposure indicators. Indicators with large weight (subjective weight/objective weight) were the proportion of population older than 65 years old (0.31/0.30), the proportion of population older than 65 years old (0.16/0.23), infant mortality rate (0.18/0.20), the total Gross Domestic Product (GDP) per capita (0.33/0.21), the proportion of illiterate in the population older than 15 years old (0.19/0.28), history frequency of floods (0.75/0.75). The mean vulnerability index (VI) calculated by subjective method was 0.35 with the standard deviation of 0.10; the mean vulnerability index calculated by objective method was 0.31 with the standard deviation of 0.08. The two weighting methods showed consistent results of vulnerability index (ICC = 0.975, P < 0.01). VI of most districts dropped in the interval of 0.30 - 0.39. Districts with subjective VI > 0.50 or objective VI > 0.40 should pay more attention to floods, including parts of the coastal areas, Beijiang River Basin, the eastern tributary area of Dongjiang River and the northern part of Pearl River Delta. Dapu district of Meizhou (0.55/0.45), Dianbai district and Maogang district of Maoming (0.54/0.48) were most vulnerable. Districts of Heyuan, Dongguan, Zhaoqing and Huizhou were less vulnerable, Yuancheng district of Heyuan showed least vulnerable to floods (0.15/0.12) followed by Dongguan (0.18/0.16), Duanzhou district (0.18/0.16) and Guangning (0.17/0.15) district of Zhaoqing. The score of indicators differed among different level of vulnerability (P < 0.05). CONCLUSION: Different regions of Guangdong province showed different vulnerability to floods, vulnerable areas should be priority in the prevention and control of floods.

[A logistic regression analysis on the factors influencing effect of cardiopulmonary resuscitation in emergency department].

OBJECTIVE: To look for the independent factors influencing the effect of cardiopulmonary resuscitation (CPR) in emergency department. METHODS: The data of patients involved in the study were retrieved from 72 network emergency hospitals in Shenzhen from September 2004 to January 2009. The data base was set up with EpiData software, according to questionnaires about cardiopulmonary arrest (CA) patients treated with CPR, and analyzed with SPSS 13.0 software. The binary Logistic regression was carried out with 8 factors which had emerged statistical significance through single factor analysis. RESULTS: A Logistic regression analysis on the factors influencing return of spontaneous circulation (ROSC) in emergency department showed the ventrical fibrillation [VF, odds ratio (OR)=3.071, P=0.000, 95% confidence interval (95% CI)=2.019-4.670] and pulseless electric activity (PEA, OR=1.730, P=0.036, 95% CI=1.036-2.890) were protective factors compared with asystole; electric shock was a protective factor (OR=1.574, P=0.015, 95% CI=1.093-2.265); adrenaline ≤4 mg group had higher likelihood of obtaining ROSC compared with group receiving ≥5 mg of adrenaline (OR=1.483, P=0.037, 95% CI=1.024-2.147); duration of CA before CPR was a risk factor (OR=0.961, P=0.000, 95% CI=0.946-0.976). A Logistic regression analysis on the factors influencing survival to admission in emergency department showed the VF was a protective factor compared with asystole (OR=2.013, P=0.002, 95% CI=1.299-3.121); adenine ≤4 mg group had higher likelihood of survival to admission compared with group ≥5 mg (OR=2.289, P=0.000, 95% CI=1.487-3.524); duration of CA before CPR was a risk factor (OR=0.951, P=0.000, 95% CI=0.933-0.969). CONCLUSION: Rhythm of heart, the duration of CA, electric shock and accumulated adrenaline dosage were independent influencing factors for ROSC in emergency department. Rhythm of heart, the duration of CA and accumulated adrenaline dosage were independent influencing factors for survival to admission in emergency department.