【Abstract】 Objective To understand the population composition of rat?shape rodents in Guangdong province and its breeding in different seasons, and to provide the theoretical basis for the control of rodents. Methods Rodents were caught daily by snap trap method in township sampled randomly monthly. The rodents captured were identified and dissected, recording the pregnancy situation. Results The trapping rate of rat?shape rodents was 9.98% in the residential areas, including 4.98% of rats. It included 48.73% Rattus norvegicus, 15.50% R.tanezumi mice, 35.17%Suncus murinus and 0.59% Mus musculus. The average pregnancy rate of R.norvegicus was 4.06% and the average litter size was 5.35. The average pregnancy rate of R.tanezumi was 5.63%  and  the  average  litter  size  was  2.76.  That  of  Suncus  murinus  was  15.00%  and  its  litter size was 3.32. Conclusion R.norvegicus and Suncus murinus are the dominant species in the residential areas in township. M.musculus is the rare specie. The breeding seasons of R.norvegicus and R.tanezumi are in spring and autumn, and the breeding peak in spring is higher than that in the autumn. It has also a small reproduction peak in August. However, Suncus murinus can breed all year round, and there are also two peaks. One peak is in March?June, the other is in October?November. It should strengthen the killing of rodents in spring and autumn.

Objective To determine the susceptibility of Rattus tanezumi to Brodifacoum in the laboratory.Methods No-choice feed was performed according to the method of rodent resistance monitoring group of China.Firstly,the males and females were separated,then divided into groups at random.The rodent was feed with 0.000 16% brodifacoum bait at 5 different feeding days.The data was analyzed with Bliss software.Results There was no significant difference between the susceptibility of different sex R.tanezumi to Brodifacoum( P _b>0.05, P _{LFP 50}>0.05).The virulence regression equation was y=2.49+5.70 x,and the LFP ₅₀,LFP ₉₉ and its 95% confidence limits were 2.75(2.39-3.17)d and 7.04(4.89-10.13)d days respectively.Conclusion According to the revised standard of WHO that the integer of LFP99 value was the resistance distinguish standard,the survivor that were fed with 0.000 16% bait for 8 d was the resistance species in Zhanjiang.

Objective To understand susceptibility change of Bandicota indica in Zhanjiang to Warfarin, providing scientific basis for well-organized deratization. Methods The males and females were firstly separated by sex and then divided into groups at random. No-choice tests were carried out using the Warfarin bait at concentration of 0.002% at five different feeding days. The relationships between death rates and the different feeding days were analyzed by Bliss software. Results For the susceptibility to Warfarin, there was no significant difference ( P _b>0.05, P _{LFP 50}>0.05) between males and females. Calculated based on these data, the LF-P line was y=4.25+2.57 x, and LFP ₅₀, LFP ₉₉ and its 95% confidence limits for Bandicota indica were 1.95(1.48-2.58)d and 15.71(6.29-39.23)d, respectively. Conclusion Comparing with the susceptibility results detected in 1989, the local Bandicota indica was still sensitive to anticoagulant rodenticides though the proportion of high tolerant individual increased. The rodenticide could be continued to kill Bandicota indica as long as the quality of the poison bait was assured and the palatability was enhanced.

Objective To determine the susceptibility of Rattus rattoides to bromadiolone and provide base data for R.rattoides resistance to bromadiolone. Methods The males and females were firstly separated and then divided into groups at random. No-choice tests were carried out using 0.0002% bromadiolone bait at five different feeding days. The relationship between mortality and different feeding days were analyzed by Bliss software. Results There was no significant difference ( P _b>0.05,P _{LFP 50}>0.05) between male and female _R.rattoides for bromadiolone susceptibility. The LFP line was y=0.52+7.58 x. On combination of the sex data, LFP ₅₀,LFP ₉₉ and their 95% confidence limits were 3.90(3.55-4.28) and 7.90(6.24-10.00) days respectively. Conclusion The revised rodent resistance criterion of WHO was integer of LFP ₉₉. According to it, _R.rattoides was still alive after fed on 0.0002% poison bait for 8 days in Zhanjiang, and then it could be considered to have resistance.

Objective Study on the control ratios of rodents' parasitic flea and ground free flea after resort spraying on the ground in the focus of house mice plague.Methods After diluted the liquid with water(1∶160) 5% Fendona was resort sprayed on the indoor and the outdoor(80 ml/m ²) according to per house 100 g the powder,especially on the foot of a wall,the kennel,the holes and traces of rodents(150-180 ml/m ²).Through counted control ratios with the indices of rodents' parasitic flea and the ground free flea before the application and after the application.Results The control ratios of rodents parasitic flea and ground free flea are 33.54% and 71.39% respectively.Conclusion On-the-spot the control ratios of rodents' parasitic flea is very limited,but the rural sanitation is key to the question.

Objective To study the dynamic changes of murine-like-animal community in Zhanjiang,Guangdong from 1950 to 2000. Methods Data of plague surveillance in Zhanjiang during the past 50 years were collected and sorted out to describe and analyze the changes of murine-like-animal community by year. Results A total of 237 831 murine-like-animals were captured and identified,including 11 species of three genera in two orders. Totally,157 412 murine-like-animals in four species of three genera were captured domestically,with Rattus flavipectus as dominant species,accounting for 68% of the total,and Suncus murinus and Rattus norvegicus as common species,accounting for 25% and 6%,respectively. A total of 80 419 wild murine-like-animals in eight species of two genera in two orders were captured,with R.losea and Bandicoot indicia as dominant species,accounting for 80% and 18% of the total,respectively,and R.rattus hainanicus and Suncus murinus as common species. Conclusion In domestic rats of urban areas, R.flavipectus had been replaced by R.norvegicus which had become a dominant species there,but in rural areas, R.flavipectus was still the dominant species. Among wild rodents,population of R.losea reduced yearly,but that of Bandicota indica increased yearly.

Objective To study the development and evolution of resistance to anticoagulant rodenticide in domestic rats since its use in Zhanjiang,Guangdong province and to provide scientific evidence for its use.Methods Rattus norvegicus and Rattus flavipectus were captured in varied periods from different areas of Zhanjiang.Their resistance to anticoagulant rodenticide was tested in lab based on the standard methods developed by a national collaboration study group.Results(Resistance to) the first-generation anticoagulant rodenticide gradually generated in individuals from the susceptible population of R.flavipectus ten years after its use,and a resistant population of R.flavipectus formed in Zhanjiang 17 years after its introduction.But,use of the second-generation anticoagulant rodenticide bromadiolone could reduce their resistance to the first-generation one.Frequency and methods to use anticoagulant rodenticides in varied areas the same period could influence the resistance in R.flavipectus,which could be maintained at a lower level in R.norvegicus,with a statistically significant difference between them((χ ²=)(41.676),( P<(0.01)).Conclusion Rules of the development and evolution of resistance in rodents should be complied with in use of anticoagulant rodenticides,with periodically monitoring for it and properly selecting the first and second-generation anticoagulant rodenticides to ensure their effects and prolong their use period.

Objective In Zhanjiang proper,the first generation anticoagulant rodenticide (mainly diphacinone-Na) had been used for more than 20 years. To investigate the resistance of Rattus flavipectusand R.norvgicusto the first generation rodenticide after Bromadiolone (a second generation anticoagulant rodenticide) were used for 4 years. Methods No-choice feeding tests were carried out and the results obtained compared with those 4 years ago. Results The resistance of the two commensal rodent species,espcially R.flavipectus,to the first generation rodenticide have declined. Conclusion In the areas where resistance of commensal rodents to the first generation rodenticide had evaluated,After Bromadiolone was used for a few years,the resistance should be slow down could hold back.