ABSTRACT
s] Objective To evaluate the effect of comprehensive schistosomiasis control measures with focus on total removal of cattle and sheep in Junshan District,Yueyang City. Methods The retrospective review and field survey were implemented in the pilot villages in Junshan District. The data of Schistosoma japonicum infection status of human,cattle,sheep and Oncome-lania hupensis snails,and density of snails were gathered and modeled in the period of 2006 to 2016. Results The prevalence of schistosome infection in residents in the pilot villages decreased from 3.44％ in 2006 to 0.59％ in 2012(F = 14.501,P =0.013). After removal of all the cattle and sheep in 2013,the prevalence of schistosome infection in the residents decreased to zero in 2016(F=14.148,P=0.033). The density of living snails decreased from 0.8833/0.1 m2 in 2006 to 0.3088/0.1 m2 in 2012(F=76.250,P=0.005). Conclusion The comprehensive schistosomiasis control strategy with focus on cattle and sheep removal is remarkably effective.
ABSTRACT
Polymerase chain reaction (PCR) is a simple, quick and highly sensitive method. However the accuracy of the conventional PCR assay was often affected by false positives and false negatives. In this study, a protocol competitive PCR was used to reduce the false results in screening for selectable marker-free (SMF) Xa2l transgenic rice plants. The competitive template of Xa21 was the endogenous Xa2l homologous sequence located on chromosome 11. The competitive template of the selectable marker gene, hygromycin phosphotransferase (hpt), was an additive DNA extracted from hpt transgenic Nipponbare (Oryza sativa L). Through competitive PCR analysis of transgenic T1 plants produced by double right border binary vector, false positive or false negative samples were effectively diminished, and genuine SMF Xa21 transgenic plants were obviously obtained. Comparing with the conventional non-competitive PCR, competitive PCR increased the accuracy for selecting SMF Xa21 transgenic plants. The results of bacterial blight (BB) resistance tests and hygromycin B resistance assay of SMF Xa21 transgenic plants testified the reliability of this method.