Search

The present study is the first to investigate resistance levels ofTetranychus cinnabarinus(Boiduval) in mulberry in southwest China. The toxicity and resistance of seven common acaricides, including dichlorvos, phoxim, methomyl, pyridaben, propargite, abamectin and chlorfenapyr, were assayed for seven mulberry field strains of mites along with a laboratory susceptible strain (SS). The results indicated that most field strains exhibited low to moderate levels of resistance. Mengzi and Xiangyun had moderate resistance to phoxim (RR = 31.45 and 26.22, respectively). The Qiaojia, Luliang, Mengzi and Heqing strains showed moderate resistance to chlorfenapyr (RR = 14.98–22.52). Correlation analysis of resistance ratio in seven acaricides indicated that methomyl and abamectin were negatively correlated. The results provide information for acaricide rotations and resistance management of spider mite in mulberry plantations. [ABSTRACT FROM PUBLISHER]

Background: One of the goals of this study was to learn the coverage, safety and logistics of a mass vaccination campaign against typhoid fever in children and adults using locally produced typhoid Vi polysaccharide (PS) and group A meningococcal PS vaccines in southern China. Methods: The vaccination campaign targeted 118,588 persons in Hechi, Guangxi Province, aged between 5 to 60 years, in 2003. The study area was divided into 107 geographic clusters, which were randomly allocated to receive one of the single-dose parenteral vaccines. All aspects regarding vaccination logistics, feasibility and safety were documented and systematically recorded. Results of the logistics, feasibility and safety are reported. Results: The campaign lasted 5 weeks and the overall vaccination coverage was 78%. On average, the 30 vaccine teams gave immunizations on 23 days. Vaccine rates were higher in those aged ≤ 15 years (90%) than in adolescents and young adults (70%). Planned mop-up activities increased the coverage by 17%. The overall vaccine wastage was 11%. The cold chain was maintained and documented. 66 individuals reported of adverse events out of all vaccinees, where fever (21%), malaise (19%) and local redness (19%) were the major symptoms; no life-threatening event occurred. Three needle-sharp events were reported. Conclusion: The mass immunization proved feasible and safe, and vaccine coverage was high. Emphasis should be placed on: injection safety measures, community involvement and incorporation of mop-up strategies into any vaccination campaign. School-based and all-age Vi mass immunizations programs are potentially important public health strategies for prevention of typhoid fever in high-risk populations in southern China. [ABSTRACT FROM AUTHOR]

The carmine spider mite (CSM) Tetranychus cinnabarinus has become a serious pest in China and has developed resistance to acaricide propargite as it is used to control mites worldwide including T. cinnabarinus . In this study, a resistant colony of T. cinnabarinus , PRR34 (37.78-fold resistant ratio), was established after 34 generations of propargite selection, and cross-resistance patterns of 7 other acaricides were determined in comparison with a susceptible strain (SS). The contribution of detoxification enzymes to propargite tolerance were investigated using biological, biochemical and molecular approaches. Enzyme inhibitor synergist tests suggested glutathione S -transferases (GST) involvement in propargite-resistance of PRR34, and GST activity against 1-chloro-2,4-dinitrobenzene (CDNB) was correlated with the development of resistance. Eight novel GST genes ( TcGSTd1, TcGSTd2, TcGSTm1, TcGSTm2, TcGSTm3, TcGSTm4 and TcGSTm5 ) were cloned, and phylogenetic analysis showed that the eight GST genes were most closely related to GST family delta and mu from Tetranychus urticae . Quantitative RT-PCR revealed that the expression level of GSTs in PPR34 strain increased in larvae, nymphs and adults, while decreased in eggs compared with that of SS. Collectively, these results support a role of GSTs in mediating resistance to propargite in the PRR34 strain. TcGSTd1,TcGSTd2 and TcGSTm2 genes might play significant roles in propargite resistance of CSM, especially at adult stage. This is the first attempt to define specific genes involved in GST mediated propargite resistance of T. cinnabarinus at the transcriptional level. [ABSTRACT FROM AUTHOR]