Plasmodium yoelii yoelii-Anopheles stephensi system was chosen as the experimental model in studying the effects of pyrimethamine on oocyst formation of the plasmodium species. The drug was given by allowing mosquitoes to feed on infected and pyrimethamine treated mice or by feeding them directly with pyrimcthamine-sugar water. The infective rate and the number of oocysts formed after drug administration were reduced, the oocysts formed being smaller and their daily growth rate slower than that of the controls. Electron microscopic and Feulgen staining studies showed that the cytoplasm of the affected oocysts contained many vacuoles, pigment aggregations and black aggre-gates (Fig. 4). No nucleus appeared in the affected oocysts, which were presumably deteriorated and became "black spores". The amount of DNA in drug-affected oocysts was scanty. No sporozoites were found in the salivary glands of these mosquitoes. It was suggested that pyrimethamine interfered with DNA synthesis of oocysts.

ObjectiveTo investigate effect of conducting training of autism spectrum disorder （ASD） early screening skill on improving the ability to early identify ASD of medical staffs in primary care hospitals. MethodsIn September 2021， the training of ASD early screening skills was carried out for medical staffs from 20 primary care hospitals in Chengdu. After training， the training effect was evaluated. The numbers of referrals from primary care hospitals to superior hospitals， confirmed ASD as well as their average diagnostic age of children with ASD before and after training were used as evaluation indicators. ResultsAfter training， the number of children with suspected ASD referred by primary care hospitals was more than that before training ［（16.65±11.60） vs. （3.40±2.23）， t=5.431， P<0.01］， the number of children diagnosed with ASD was more than that before training［（6.85±4.93） vs. （2.45±1.67）， t=4.171， P<0.01］， and the differences were statistically significant. As for the diagnosed age of ASD children， after training， the average age was lower than that before training ［（34.95±11.67） vs. （42.2±14.64）， t=-2.553， P=0.019］. ConclusionTraining of ASD early screening skills for medical staffs in primary care hospitals may help to improve their ability to early screening ASD children.