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 45224 dengue fever cases and 6 deaths were notified in Guangdong Province in 2014,with an incidence of 47.3 per 100000 people.The elderly(65+years)represented 11.7%of total indigenous cases with the highest incidence(72.3 per 100000).Household workers and the unemployed accounted for 23.1%of indigenous cases.The majority of indigenous cases occurred in the 37th to 44th 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.

Defervescent dengue patients might be a potential source of infection for vector mosquitoes

Background:Dengue is a re-emerging public health problem and mosquito-borne infectious disease that is transmitted mainly by A edes aegypti and Ae.albopictus.Early diagnosis,isolation,and treatment of patients are critical steps for dengue epidemic control,especially to prevent secondary transmission of dengue virus(DENV).However,little is known about defervescent dengue patients as a source of infection.Methods:This case study describes 1268 dengue patients hospitalized at Guangzhou Eighth People's Hospital from June 2013 to December 2014.The viral loads of each individual were measured using real-time reverse transcription-polymerase chain reaction.Ae.aegypti and Ae.albopictus were exposed to blood meal with gradated dengue viral loads to characterize the relationship between viremia in dengue patients and the vector competence of vector mosquitoes.Results:The viral numbers in the blood were measured,ranging from 108 to 103 copies/ml from day 1 to day 12 after fever onset Vector competence analysis o fA e.aegypti and Ae.albopictus indicated that viremia>104 copies/ml can still infect vector mosquitoes,which implied that the defervescent dengue patients might be a source of infection.Conclusions:The results of this study indicate that some defervescent dengue patients still have sufficient viral load to infect vector mosquitoes.Therefore,the protection against mosquito biting for these people should be extended to prevent secondary transmission events.

Correlation between longitudinal crack occurrence and mold heat transfer in continuous casting based on process data mining

The correlation between the longitudinal crack occurrence and integrated heat transfer of the mold with data mining methods was investigated.Firstly,three kinds of support vector machine models based on principal component analysis with different input features were established to explore the effect of integrated heat transfer on the accuracy of the prediction model for the longitudinal crack.The results show that the accuracy was improved while features including mean and standard deviation of integrated heat transfer were added.Then,the difference in integrated heat transfer between defect and normal samples under the same process parameters was quantitatively compared.Compared with normal samples,the temperature difference of cooling water for defect samples decreased by 0.65%,and the temperature difference fluctuation increased by 31.1%.Finally,the literature data were used to provide support for the quantitative correlation according to defect formation mechanism.A new criterion for the prediction of longitudinal crack and a discovering method for correlation between product quality and process parameters in the manufacturing industry have been provided.