Objective To study the population dynamics and the distribution characteristics of the vector mosquitoes of Japanese encephalitis (JE) in Kaijiang county, Sichuan province for providing a scientific basis for JE control and prevention. Methods Three sampling points were selected for each of the surveillance sites, the rice fields, the pens for livestock and the rooms for people in JE epidemic area of Kaijiang county during May to September 2011, and mosquitoes were caught 15 min a time, 2 times a month, with the captured insects identified. Results A total of 4734 mosquitoes were caught from June to September with an average density of 210.4/labor hour. The density was 247.3/labor hour in the rice fields, 267.7/labor hour the pens for livestock, 114.3/labor hour the rooms for people, respectively. Of the 1855 mosquitoes captured in the rice fields, Culex tritaeniorhynchus accounted for 93.21% and Cx. pipiens quinquefasciatus for 5.55%, and of the 2023 mosquitoes captured in the pens for livestock Cx. tritaeniorhynchus accounted for 44.04%, Cx. pipiens quinquefasciatus for 33.81% and Anopheles sinensis for 22.15%. Of the 856 mosquitoes captured in the rooms for people Cx. pipiens quinquefasciatus accounted for 72.20% and Cx. tritaeniorhynchus for 22.08%. The Cx. tritaeniorhynchus density peaked in the rice fields in the first ten days and the last ten days of June (570.7/labor hour and 583.3/labor hour), in the pens for livestock in the last ten days of July (265.3/labor hour) and the last ten days of September (533.3/labor hour), and in the rooms for people in the first ten days of August (70.7/labor hour). Conclusion In terms of the JE vector mosquitoes in Kaijiang county, Cx. tritaeniorhynchus is mainly distributed in the rice fields and pens for livestock, and Cx. pipiens quinquefasciatus mainly in the rooms for people. The peak season of JE incidence is consistent with the peak density distribution of Cx. tritaeniorhynchus in the rice fields and pens for livestock.

Objective To identify the dynamics and distribution of the dengue mosquito population in Kaijiang county, Sichuan province for effective dengue fever control and prevention. Methods The container index of Aedes albopictus mosquitoes was examined at different habitats of Kaijiang county from June to October, 2010. Adult mosquitoes were captured on human baits to calculate the adult mosquito density. Results The average container index of mosquito larvae was 6.25% after investigation of 2639 water containers and 165 positive habitats. This index ranged from 1.65% to 12.07% from June to October with difference between months (χ²＝71.50,P＜0.01). As for different habitats, the highest index was found in special habitats (38.83%), followed by mountainous woods (18.18%), and farmland (16.53%), while others ranged between 2.40% to 6.69% in other places, with statistically significant differences (χ²＝271.89,P＜0.01). As for containers, the highest index was found in waste tires (38.83%), while others ranged from 2.03% to 12.77% with statistical differences (χ²＝216.05,P＜0.01). The overall adult density was 4.47/man-hour, which ranged between 2.67 to 6.50/man-hour from June to October but, there was no statistical difference between months (t＝0.09-1.31,P＞0.05). The highest density was found in mountainous woods (9.60), followed by farmland (7.40) and special places (5.80), which were obviously higher than those in other environments (1.00-2.00) (t＝ 2.78-3.64,P＜0.05). Conclusion As dengue mosquitoes, Ae. albopictus, were widely distributed in the county, it is important to implement prevention and control measures against the disease.

Objective To study the impact of farmland climate factors on the rodent community. Methods From 1978 to 1993, canonical correlation analysis of the farmland rodent density and climate factors in Kaijiang county, Sichuan province was conducted. Results In the period, the overall farmland rodent density was 5.58%-26.57% ; Apodemus agrarius density 1.91%-18.41% , Rattus norvegicus density 0.68%-10.86% , and Anourosorex squamipes density 0.47%-9.50% . Among the canonical correlation coefficients between 12 climate factors including temperature, humidity, rainfall and sunshine, and four variables (overall rodent density, Ap. agrarius density, R. norvegicu density, An. squamipes density), the first couple (correlation coefficient r＝1.0000) was statistically significant (χ²＝248.7032,P＜0.01). The largest coefficient of the rodent density was noted in the overall rodent density (4.7748), and the largest coefficient of the climate factors was the average sunshine from July to August (-3.1532), followed by average humidity from July to August (-1.6177) and then average rainfall from July to August (-1.4652). All were negatively correlated. Conclusion Farmland rodent quantity was mainly affected by average sunshine, humidity and rainfall from July to August.

【Abstract】 Objective To study the population composition and quantity change of rodents in Kaijiang county, Sichuan province, so as to provide basic information for rodent control. Methods The rodents density was investigated by night trapping in the indoors and outdoors. Results The rodent density in the field was higher in 1989-1990 and 1992-1993, reaching about 18.85%-26.57% and steady in 4.21%-14.88%. The rodent density in the indoors was in the peak in 1986 (9.47%), and it was 1.96%-7.26% in other years. The rodent density in the field rodent was higher than that in the indoors. The dominant species were Apodemus agrarius (51.59%), Anourosorex squamipes (27.36%) and Rattus noregicus (18.68%) in the field. However, The dominant species in the indoors were R.norvegicus (64.32%), Mus musculus (26.58%) and An.squamipes (7.99%). The dominant species exchanged in different years. Conclusion The rodent density and its population dynamics were affected by density dependent factor and non?density dependent factor in the field, but that in the indoors was relative to the control of rodent.

Objective To investigate the epidemic tendency of Japanese encephalitis(JE) in Kaijiang county, Sichuan province using the information of epidemiology in 2006, so as to provide basic information for JE prevention and control. Methods All of the 31 cases of JE in Kaijing county were interviewed individually by questionnaire on epidemiology and vaccine inoculation rate in 2006. The blood serum of the JE cases in early stage was collected, that of 9 years old healthy children were collected in May, and that of pigs were collected in each 10 days from June to July. All blood serums were tested by ELISA method. Results The total reported cases of JE were 31 in 2006, with incidence rate of 5.49/100 000. The incidence rate in flat area (6.98 per 100 000) was higher than that of hilly area (2.61 per 100 000) ( χ ²=4.41, P<0.05), the cases were intravenous drip distributed. There were more cases in the last ten days of July and the first 10 days of August, with incidence rate of 54.84% and of 29.03%, respectively. The results showed that boy incidence was more than that of girl (2.88∶1). The patients who were under 3 years old accounted for 70.97% of total. 60.00% of the total cases lived in unsanitary conditions, although 86.67% of them using mosquito net at night. The knowing rate of JE cases guarders on JE prevention and control knowledge was only 13.33%, the immunized ones with JE vaccine accounting for 6.45%, the sequelae rate of JE cases for 19.35%(6/31). About 4783.74 Yuan RMB were needed for each case in clinic and in hospital averagely. JE vaccine immunization rate of the 1-7 years old children accounting for 46.74% (79/169). On clinical, the light and the medium were respectively 41.94% and 38.71%. The positive rate of serum antibody in 2-9 years old healthy children was 63.77%(88/138), of which that of 2 years old children (33.33%) was lower than that of 3-9 years old children, but the difference was of no statistics significance ( χ ²=11.14, P>0.05). The peak of antibody positive rate of pigs was in the second 10 days of June, and the difference of antibody positive rate in every 10 days in June and July was of no statistics significance ( χ ²=6.30, P>0.05). The clinical serum diagnosed rate of JE cases was 80.64%(25/31). Conclusion Strengthening propaganda of JE prevention and control knowledge in rural area, increasing JE vaccine immunization rate of children under 7 years old, successfully prevention and control vector mosquitoes for JE will be a good strategy of JE prevention and control in Kaijiang county.

Objective To study the prevalent status and epidemic tendency of Japanese encephalitis(JE) in Kaijiang county and to provide scientific base for JE prevention and control. Methods JE Epidemic data from 1960 to 2003 were callected,serology surveillance of JE patient,healthy children and pigs were done from 2002 to 2003 by the reverse passive hemagglutination inhibition test (RPHI). Results Annual average incidence rate was 8.16 per 100 000 in 19602003,fatality rate was 5.68%. August is the peak time of onset. The incidence rate of flat area (8.82 per 100 000) was higher than that of hilly area (6.86 per 100 000) (χ ²=20.43, P<0.005). The patients less than 10 years old accounted for 94.51% of total patients. The positive rate of serum antibody in healthy children was 51.97%,of which that of 24 years old children (31.03%) was significantly lower than that of 514 years old children (64.89%) (χ ²=16.86, P<0.005). The peak of antibody positive rate of pigs was in July,and antibody positive rates were significantly different (χ ²=84.68, P<0.005) every ten days in June and July. The clinical serodiagnosed rate of JE cases was 61.54%. Conclusion Incidence rate significantly differs in every year. It may be corelated with air temperature in the locality,rainfall,mosquito intermediary and immunity level. Strengthening JE vaccine immunization in 10 years old children and raising JE immunization coverage rate for them are the keys for controlling prevalence of JE.