ISSN 1003-8280 CN 10-1522/R 中国疾病预防控制中心 主办
Objective: To investigate the situation of Rickettsia, Anaplasma, and Ehrlichia infections in Dermacentor silvarum and their genetic diversity in the Inner Mongolia Autonomous Region (Inner Mongolia), China. Methods: A total of 76 adult parasitic ticks were collected from the body surface of livestock in Dorbod Banner in Ulanqab and Tumed Left Banner in Hohhot, Inner Mongolia. All of them were morphologically and molecularly identified. Rickettsia in the ticks was examined using primers targeting the conserved regions of both 16S rRNA and citrate synthase (gltA) genes. Anaplasma and Ehrlichia were examined using genus-specific primers targeting the 16S rRNA gene. For positive specimens, nested PCR was used to amplify the gltA gene and the heat shock protein gene (groEL). PhyML 3.0 software was used for constructing maximum likelihood phylogenetic trees. Results: All the captured ticks were identified as D. silvarum. A total of 8 ticks tested positive for Rickettsia, with six (6/35, 17.14%) from Dorbod Banner and two (2/41, 4.88%) from Tumed Left Banner, all being identified as R. raoultii by sequencing. The phylogenetic analysis based on the 16S rRNA, gltA, and groEL genes revealed that the strains were divided into two clades in the phylogenetic tree, suggesting that R. raoultii was genetically diverse in this area. All the samples were negative for Anaplasma and Ehrlichia. Conclusions: R. raoultii is epidemic among Dermacentor ticks in Inner Mongolia, with certain genetic diversity. Concerning its human pathogenicity, the high positive rate of R. raoultii in certain areas of Inner Mongolia suggests a potential risk of human infections.
【Abstract】 Objective To study the control effect of cashew nut shell liquid(CNSL) and anacardic acid from CNSL to Oncomelania hupensis, and provide the basis for the application of CNSL. Methods The mixture of anacardic acid was obtained by separating extracts by silica gel column. The molluscicidal activities of CNSL and the mixture of anacardic acid against O.hupensis were tested according to laboratory molluscicidal test method recommended by WHO. Results The purity of anacardic acid extracted by silica gel column was 89.32%. The LC50 values of CNSL and anacardic acid mixture to snails were 0.831 mg/L and 0.523 mg/L after treatment for 48 hours, and the LC90 values were 2.180 mg/L and 1.439 mg/L respectively. The inhibition rates of CNSL and anacardic acid to up?climbing of snails were 16.7% and 13.3% at the concentration of 2 mg/L, respectively. When the concentration was all 2 mg/L. However, when the concentration exceeded 4 mg/L,the up?climb rate was zero. Conclusion It is very effective for CNSL to control snails, and anacardic acids is the main active ingredient. CNSL, as plant molluscicide, will be widely used in the control of snails.
【Abstract】 Objective To understand the population composition and seasonal fluctuation of fleas parasitized on Rattus tanezumi in Leizhou city. Methods R.tanezumi were captured in selected districts of Leizhou city from 1985 to 2004. Fleas were collected from their body surface and identified to count the flea index and its composition proportion. Results A total of 1721 R.tanezumi were caught, and about 2345 fleas belonged to 4 species were collected. Among them, Xenopsylla cheopis and Leplopsylla segnis were the dominant species, the average index of them were 1.24 and 0.12, and the proportion of them were 91.13% and 8.66%, respectively. The index and composition proportion of Pulex irritans and Ctenocephalides felis felis were very low. Conclusion R.tanezumi was the dominant host of X.cheopis and L.segnis. The number of X.cheopis increased year by year, but that of L.segnis decreased year after year.