ISSN 1003-8280 CN 10-1522/R 中国疾病预防控制中心 主办
Objective To investigate the species composition, diversity and prevalence of the infection of Gasterophilus botfly larvae in horses from Duolun county, Inner Mongolia Autonomous Region. Methods Adult horses were treatedorally using ivermectin, the botfly larvae were collected from the feces and identified. Results Six species in the genus Gasterophilus were collected from each individual horse and with the following prevalence: G. intestinalis 53.04%, G. nasalis 24.00%, G. haemorrhoidalis 10.61%, G. pecorum 6.96%, G. nigricornis 3.13%, G. inermis 2.26%. Conclusion The species of Gasterophilus in Duolun county are abundant, and the horse gastric myiasis is prevalent in this area.
Objective To investigate the trends of Culex tritaeniorhynchus population dynamics in Liaoning province and to confirm that whether they carry Japanese encephalitis(JE)or not, which can support a scientific basis for establishing the strategy of prevention and control of Japanese encephalitis virus. Methods Culex tritaeniorhynchus, captureusing mosquito-lured lamp in 14 cities of Liaoning province during 2006-2013, were used to investigate the population composition and distribution and seasonality. Results Populations of Cx. tritaeniorhynchus in Liaoning province are mainly distributed in three cities, Dandong, Dalian and Panjin city, Dandong which has the highest distribution, the ratio of Culex is 78.43%, and the highest density is up to 780.20 Culex/(equipment·h) in 2007. In addition, Cx. tritaeniorhynchus were captured in Dalian, Panjin, Yingkou, Huludao and Jinzhou cities in different months. The highest density of Culex is appeared in September.Conclusion Culex mainly distributed in paddy growing areas of coastal cities in Liaoning province, including Dandong, Dalian, Panjin and Huludao;the most serious areas is Dandong city with the highest density and highest viral infection. In Lioaoning provience, there was a coincidence of early populations, high density and high JE infection. This phenomenon proves there is a relationship of Culex population trends and morbidity of JE, therefore, investigating the incidence of JE and the trends of Culex could not be ignored.
Objective To determine the complete genomic sequences of 3 Dengue 2 virus (DEN-2) strains isolated in Guangdong province, China and to investigate their genotypes and sources. Methods The complete genomic sequences of 3 DEN-2 strains (GD09/93, GD05/98, and GD19/2001) from Guangdong province were established by RT-PCR amplification. The phylogenetic tree of DEN-2 was constructed by Kimura method. Results The complete genomic sequences of 3 DEN-2 strains were 10 723 nucleotides (nt) in length and contained a single long open reading frame (ORF) of 10 173 nucleotides (97-10 269 nt), encoding 3391 amino acids. The ORF encoded structural and non-structural proteins, flanked by 5' and 3' non-coding regions. Comparing GD05/98 with GD09/93, GD05/98 with GD19/2001, and GD09/93 with GD19/2001, the nucleotide sequence homologies were 93.3%, 92.4%, and 97.6%, respectively, and the deduced amino acid sequence homologies were 96.7%, 96.5%, and 98.5%, respectively. Conclusion The DEN-2 strains are pathogenic in suckling mice. Compared with DEN-2-04 strain (nonpathogenic in suckling mice), there are 18 amino acid substitutions that confer changes in charge or polarity. The charge changes at PrM-134, NS2A-153, and NS4B-102 have a relatively strong impact on the antigenicity. GD05/98 strain falls within the groupⅡ comprising Thailand strains, while GD09/93 and GD19/2001 strains fall within the group Ⅳ comprising strains from Indonesia, Australian and Taiwan. There are different DEN genotypes in China, and one genotype of DEN-2 may be transmitted in different periods.
Objective To determine the population dynamics of mosquitoes and midges before and after sunset. Methods Net traps were set along certain locations at varying heights to capture the insects before and after sunset. Results Most of the captures were midges, amounting to 1039 of 7 genera, dominated by the genus Culicoides. The collected mosquitoes were of 2 species under 2 genera, totaling 53. The activity peak of the insects was approximately 1 hour after sunset. Conclusion The species composition and dynamics of mosquitoes and midges around the residential areas of Weng’ang village before and after sunset were generally clarified.
Objective This study aims to evaluate the risk for the introduction of African swine fever virus to China and to predict the potential distribution of the vectors, providing the basis for development of prevention and control strategies. Methods The adaptability analysis software, Climex, was employed to predict the potential distribution of soft ticks in China. Results The parameter setting was derived from the biological data of soft ticks and the default template parameters of Climex. The analysis revealed that the ecoclimatic indexes of soft ticks in such places as Yunnan, Guizhou, Eastern Sichuan, Chongqing, Southern Shaanxi, Hunan, Hubei, Northeastern Jiangxi, Anhui, Henan, Zhejiang, Jiangsu, Shandong and Hebei were greater than 20; these locations would be the highly suitable, potential habitats for soft ticks in China. Conclusion Some areas in China may be the natural foci of African swine fever, suggesting that the future monitoring and control should be focused on these regions.
Objective To establish a TaqMan probe?based fluorescence quantitative PCR assay for rapid detection of Dengue virus type 1 (DV1) to facilitate the clinical diagnosis. Methods A set of specific primers and TaqMan probes were designed for the RT?PCR according to the conservative gene sequences at the 5′-terminal non?coding regions of DV1. A total of 40 sera samples were collected from patients with dengue fever, and four serotypes of standard DV strains were used as the control. The specificity of the established TaqMan?based fluorescence quantitative PCR assay was determined using the RNA templates obtained through in vitro transcription in the RT?PCR of the standard strains as a positive control. The sensitivity of the assay was then compared with that of the DV?IgM/IgG?based ELISA by assessing the sera samples. Results The lowest detection limit of the established method was approximately 10 gene copies per reaction. As to the positive results among the sera samples collected from patients at different stages after onset, the RT?PCR had the highest positive detection rate during the first three days after onset (81.25%), while the ELISA?IgM had the highest positive detection rate from day 4 to day 6 after onset (85.00%). After 7 d, ELISA?IgG had the highest positive detection rate (75.00%). Conclusion The established RT?PCR assay was a highly sensitive, specific and reproducible approach for rapid detection of DV1, conducive to the early diagnosis of dengue fever.
【Abstract】 Objective To master the species and seasonal fluctuation of mosquitoes, and provide scientific basis for mosquitoes control in Beijing ports. Methods CO2?baited trap and net trap methods were used for the surveillance of adult mosquitoes, and the scoop dipping method for the surveillance of larvae. Results A total of 14 270 mosquitoes were collected, belonging to 4 genera and 6 species. They were Anopheles sinensis, Culex pipiens pallens, Cx.tritaeniorhynchus, Aedes albopictus, Ae.vexans and Armigeres subalbatus. As many as 114 mosquito larvae were collected, which were Cx.pipiens pallens and Cx.modestus. The dominant specie was Cx.pipiens pallens and its active peak was September. Conclusion The integrated management should be taken for a long time to control mosquitoes in Beijing ports.
【Abstract】 Objective To master the fly species and population composition at Beijing port and provide scientific evidence for fly control. Methods The baited fly traps method was used in this study. Results There were 30 species, 16 genera, 5 families of flies captured from April to November of 2006 and 2007. The annual average fly density was 59.7 flies/(cage ·day). There were two peaks, one was in May and the other was in September. Conclusion It was important to clean out the breeding sites for the control of flies at Beijing port.