ISSN 1003-8280 CN 10-1522/R 中国疾病预防控制中心 主办
Small mammals can bear or transmit dozens of natural-focus diseases, including mainly plague, murine typhus, hemorrhagic fever with renal syndrome, leptospirosis, and scrub typhus. Their external parasites, such as ticks, mites, fleas, and lice, are the vectors of various diseases. In view of these mammals' numerous species, wide distribution and limited migration, and given that the composition and spatial distribution of different species are always closely related with the geographical environment, climates, and their adaptive capacity, as well as a variety of diseases, it is essential to study the relationship between small mammals and multiple diseases. This paper summarizes China' s current researches on the relationship between small mammals and major or common natural-focus diseases, providing the basis for further studies of zoonotic infectious diseases and corresponding prevention and control.
Objective To evaluate the effectiveness of 0.5% pyriproxyfen granules for control of Aedes albopictus, providing the basis for mosquito control drugs and techniques during the Shanghai World Expo. Methods Larvae immersion was conducted to determine the mortality, pupation and eclosion rates at different concentrations under laboratory conditions and simulated field conditions. The control effects at 0.06 and 0.08 mg/L on different larval instars were assessed. Pyriproxyfen was applied on-site to the breeding sites of Ae. albopictus (water wells and other water bodies) in residential areas, and the mosquito density was measured using the mosquito biting method. The larvae-containing water bodies were collected from the experiment field for further observation of larval growth and development. Results (1)At the concentration gradient from 0.06 to 0.12 mg/L, the mortality of larvae was 25.75%-49.00% and the pupation rate 31.19%-40.25% under laboratory conditions; adult mosquitoes did not emerge. The pupation rate of the control group was 99.25%, and the eclosion rate was 95.47%;(2)the tested agent inhibited the pupation and eclosion of multiple larval instars at 0.06 and 0.08 mg/L, and the eclosion rate decreased as the concentration rose; (3) under the simulated environment, pyriproxyfen effectively inhibited the pupation and eclosion of mosquitoes at a concentration of above 0.5 mg/L in the shade; and(4)the density of both larval and adult mosquitoes reduced sharply at the breeding sites after on-site application of pyriproxyfen granules, according to the investigation of breeding sites and adult mosquito biting method. Only 0.24%-0.71% of the larvae collected from the water bodies developed into adults. Conclusion Pyriproxyfen can inhibit the growth and development of Ae. albopictus larvae. 1 mg/L of pyriproxyfen can be directly applied to the breeding sites for mosquito control.
Objective To confirm whether the principal vector for Japanese encephalitis (JE), Culex tritaeniorhynchus, was present in Medog and Mainling counties of Nyingtri, providing the basis for development of specific control measures; and to determine the species, abundance and distribution of vector mosquitoes in Nyingtri. Methods Light traps, human-bait mosquito nets and labor capture were used for investigation in the region. Results Cx. tritaeniorhynchus was found in Medog county with relatively high density. The predominant species in Medog county were Cx. tritaeniorhynchus and Anopheles maculatus. However, Cx. tritaeniorhynchus was not detected in Mainling county, where the predominant species was An. messeae. Conclusion The principal vector for JE existed in Nyingtri, Tibet. This species was a new record in the region that had not spread to Mainling county.
Objective To determine the distribution of mosquitoes and mosquito-borne viruses in the Yangtze River Basin within Gansu province, providing the basis for prevention and control of arbovirus-related diseases. Methods Electric mosquito- suction devices and insect-catching nets were employed to capture adult mosquitoes. The captives were classified and subject to virus isolation using cell culture. Serologic and molecular methods were used for virus identification. Results From 2006 to 2009, 10 528 mosquitoes were captured in the Yangtze River Basin, including 30 species of 5 genera. Among them were 5981 Culex tritaeniorhynchus, accounting for 56.81% of the total captives; Armigeres subalbatus, Anopheles sinensis, Cx. pipiens pallens and Aedes albopictus accounted for 33.36%, 4.95%, 3.29% and 0.95%, respectively; and unidentified species accounted for 0.64%. A Japanese encephalitis virus (JEV), a Banna virus (BAV) and 15 unidentified RNA viruses were isolated from the mosquitoes. Conclusion Cx. tritaeniorhynchus was the predominant mosquito species in the Yangtze River region within Gansu province. Since the mosquitoes were carrying such arbovirus as JEV and BAV, it should be strengthen the investigation, prevention and control of the related mosquitoes and arboviruses in the region.
Objective To identify the optimum feed formula for nymphs of Periplaneta americana. Methods The L9 (34) design was employed to analyze the impact of wheat flour, milk powder and dry yeast powder of different proportions on the nymphal growth and development of P. americana. Results Experimental results showed that after 120 d of feeding, the body length increment (19.21 mm/nymph), daily food consumption (25.94 mg/nymph), weight (532.5 mg/nymph) and consumption rate (96.69%) of nymphs fed with formula S5 were higher than the values in those fed with other feed. Conclusion The optimum formula of feed for nymphs of P. americana was wheat flour: milk powder: dry yeast flour＝2∶4∶1. Dry yeast powder was the key factor of nymphal body length increment for P. americana, which was conducive to the growth of nymphs.
Objective To identify the choice of spawning substrates by Musca domestica and Chrysomya megacephala. Methods The choice of spawning substrates by M. domestica and C. megacephala in insect rearing cages was recorded in laboratory. The odor preference of adult M. domestica was measured using a Y-tube olfactometer. Results A total of 86.58%, 6.08% and 7.34% of M. domestica laid eggs on the three kinds of substrate, wheat bran, lean meat and fish meal, respectively. The difference between the first spawning substrate and the others was significant (F＝162.97；υ＝2，15；P＜0.01). In contrast, C. megacephala laid eggs only on lean meat. In the two-way choice test for odors using an olfactometer, most of the males and females of M. domestica and C. megacephala were orientated towards lean meat, with wheat bran as the control. 85.02% of the males and 72.81% of the females of C. megacephala chose lean meat, between which the difference was significant (F＝8.66； υ ＝1，18；P＜0.01); however, the gender difference was insignificant in M. domestica. As for the comparison between fresh substrates and substrates fed by larvae, 73.43% of M. domestica laid eggs on the fed wheat bran and 57.57% on the fed lean meat, while 100% of C. megacephala laid eggs on the fed fish meal and 72.88% on the fed lean meat. Each of the egg laying amount was statistically different from that on fresh substrates. Conclusion Odors of the spawning substrate and information substances left by the larvae of the same species have a significant impact on the choice of spawning substrates by M. domestica and C. megacephala, which is of guiding significance for the development of fly attractants and the improvement of the fecundity of flies.
Objective To identify the body and subcellular distribution of acetylcholinesterase (AChE) activities in the Blattella germanica. Methods The AChE activities in different body parts and subcells were determined. Results The AChE activities in the head, chest and abdomin of male adults were 56.9%, 19.5% and 23.6% of the total activity, respectively. The difference in activity between the three body parts was statistically significant (F＝127.96，P＜0.05), where the AChE activity in the head was significantly higher than those in the chest and abdomen (P＜0.001). The subcellular organelles in descending order of the total and specific AChE activity were: mitochondria＞microsomes＞cytoplasmic solution＞nuclei and cell debris. Conclusion AChE activities were distributed in the head, chest and abdomen of B. germanica, with the highest in the head accounting for more than 50% of the overall activity. Subcellular distribution showed the highest AChE activity distribution in the mitochondria, accounting for almost 50% of the total activity.
Objective To determine whether there is distribution of Rattus norvegicus within the Tibet Autonomous Region. Methods Rats were captured using mice traps and made into specimens. Results From July to October, 1974, 15 rat species were found and 80 specimens were made in Lhasa city and Shannan mount areas. A R. norvegicus was captured in Bayi town of Linzhi city, and the specimen is deposited in the Animal Specimen Collection of the Grassland Research Institute of Chinese Academy of Agricultural Sciences. The captured rat was male, 182 g in weight, 195 mm in body length, 167 mm in tail length, 34 mm in hind foot length, 20 mm in ear length, 43.4 mm in skull length, 42.0 mm in cranial base length, 17.5 mm in nasal bone length, 19.8 mm in zygomatic width, 6.7 mm in inter-orbital width, 18.5 mm in hind head width, 13.9 mm in toothspace, and 7.7 mm in upper dentition. The other R. norvegicus was captured in Cuona county on the southern slope of the Himalayas, whereas the specimen was not retained. Conclusion R. norvegicus was found in Linzhi and Cuona county.
Objective This study aims to evaluate the risk for the introduction of African swine fever virus to China and to predict the potential distribution of the vectors, providing the basis for development of prevention and control strategies. Methods The adaptability analysis software, Climex, was employed to predict the potential distribution of soft ticks in China. Results The parameter setting was derived from the biological data of soft ticks and the default template parameters of Climex. The analysis revealed that the ecoclimatic indexes of soft ticks in such places as Yunnan, Guizhou, Eastern Sichuan, Chongqing, Southern Shaanxi, Hunan, Hubei, Northeastern Jiangxi, Anhui, Henan, Zhejiang, Jiangsu, Shandong and Hebei were greater than 20; these locations would be the highly suitable, potential habitats for soft ticks in China. Conclusion Some areas in China may be the natural foci of African swine fever, suggesting that the future monitoring and control should be focused on these regions.
Objective To evaluate the toxicity and repellent effects of 20% Tianying termiticidal emulsifiable concentrates, 5% bifenthrin suspension concentrates, 15% Wanjie termiticidal emulsifiable concentrates and 48% chlorpyrifos emulsifiable concentrates to Reticulitermes flaviceps, providing the basis for termite control. Methods The drug-impregnated filter method, toxic soil method and toxic soil pillar method were used to determine the toxicity and repellent effects of the four agents against R. flaviceps. Results Among the four tested agents, 48% chlorpyrifos emulsifiable concentrates and 5% bifenthrin suspension concentrates had the greatest contact toxicity to R. flaviceps. After 30 min of exposure to filters impregnated with 200 mg/L of them, the termite mortality reached 100% beyond 48 h. The second most toxic agent was 20% Tianying termiticidal emulsifiable concentrates, with 100% mortality beyond day 11 after treatment. The Wanjie termiticidal emulsifiable concentrates had the lowest toxicity to termites, with only 46.7% mortality beyond day 11 after treatment. All of the R. flaviceps in contact with the soil treated with ≥20 mg/L of any of the four agents died in 1 to 8 d. At a concentration of ≥200 mg/L, none of R. flaviceps could penetrate through a soil layer of 5 cm in thickness. Conclusion All of the four tested drugs can be used for termite prevention. In general, however, 20% Tianying termiticidal emulsifiable concentrates should be the agent of choice for the manufacturing industry.
Objective To assess the effects of antimicrobial peptides of Tenebrio molitor Linnaeus on K562 cells, and to compare the inhibitory effects of these peptides and of hydroxyurea on K562 cell proliferation. Methods A flow cytometry was employed to identify the anti-K562 effects of molitor antimicrobial peptides. Five parallel concentrations of the two agents were set up for comparison, and their K562 inhibition rates at different concentrations were determined using the MTT colorimetric assay. The regression equation and IC50 were computed using the SPSS software based on the relations between the concentration and inhibition rates. Results The proportion of cells in G0/G1 and G2/M phase increased, and that of cells in S phase decreased. Statistical differences were only noticed by comparing cells in G0/G1 and S phases and the control group (P＜0.01), indicating that antibacterial peptides inhibited DNA synthesis in S phase by G0/G1 phase arrest. The IC50 of antibacterial peptides and hydroxyurea were 29.98 and 3644.45 μg/ml, respectively. Conclusion The anti-K562 activity of antibacterial peptides, a result of cell cycle impairment, noticeably outstripped the inhibitory effects of hydroxyurea on K562 cell proliferation. These peptides have a good prospect for practical application in future.
Objective To verify the on-site molluscicidal activity of carbamide in hilly areas, providing the basis for promotion of this agent. Methods The experiment was performed in hilly areas invested with seedling fields and ditches using a 40 g/m2 carbamide group, a 2 g/m2 niclosamide group and a control group. Molluscicides were applied with turfs shoveled and buried in soil in spring and autumn, and the effect was evaluated in the next spring. Results The presence rate, average density and area of live snails were 59.27%, 5.66/0.1 m2 and 20 630 m2 in the carbaimide group before application of molluscicides, and became 0.44%, 0.005/0.1 m2 and 280 m2 one year after snail control, which was statistically different from the results before molluscicidal use and the control group (P＜0.01), but not different from the niclosamide group (P＞0.05). Conclusion Under pretreated dry environmental conditions, carbamide of 40 g/m2 has satisfactory molluscicidal effects and is worth promoting.
Objective To determine the resistance of Culex pipiens quinquefasciatus in different habitats in Nanchang to 6 kinds of insecticide such as dichlorvos, providing the basis for development of control measures. Methods The larvae, eggs and adults of Cx. pipiens quinquefasciatus were collected from different habitats in the east, south, west, north and central part of Nanchang city. After 1 to 2 generations of laboratory breeding, the insecticide resistance of the subjects was measured by the impregnation method. Results The resistance coefficients of the mosquitoes from 5 different habitats were 1.19-2.05, 0.57-1.80 and 0.57-1.73 times to propoxur, temephos and dichlorvos, suggesting that the mosquitoes were sensitive to these insecticides. Their resistance coefficients to pyrethroids such as permethrin and cypermethrin were 5.33-56.83 and 10.39-42.17 times, indicating different degrees of resistance. Conclusion There were no insecticide resistance of Cx. pipiens quinquefasciatus against propoxur, temephos and dichlorvos in different habitats in Nanchang, China. On the contrary, there were midium and high resistance against permethrin and cypermethrin. The monitoring of its inseticide resistance should be strengthened in conjunction with proper application of insecticides in order to delay resistance evolution.
Objective To identify the insecticide resistance of Culex pipiens pallens in different habitats of Zhejiang province, providing the basis for study of insecticide resistance mechanisms in mosquitoes and for development of specific prevention and control measures. Methods The impregnation method was employed to measure the resistance of susceptible strains and field strains of Cx. pipiens pallens from Zhoushan and Hangzhou to 6 insecticides of 4 kinds, including dichlorvos, deltamethrin, acetophenate, propoxur, allethrin and beta-cypermethrin. Results The resistance of Hangzhou strains was generally low, with the resistance coefficients ranging from 0.78 to 7.58 times in descending order as follows: dichlorvos (7.58 times)＞ deltamethrin (4.00 times)＞ acetophenate (2.88 times)＞ propoxur (2.11 times)＞ allethrin (1.11 times)＞ beta-cypermethrin (0.78 times). The resistance coefficients of Zhoushan strains were between 2.25 and 15.00 times in descending order as follows: deltamethrin (15.00 times)＞ acetophenate (7.54 times)＞ dichlorvos (5.99 times)＞ beta-cypermethrin (5.57 times)＞ allethrin (4.55 times)＞ propoxur (2.25 times). Each of the resistance coefficients of Zhoushan strains of Cx. pipiens pallens was higher than that of Hangzhou strains except for dichlorvos; the resistance coefficients of the former to beta - cypermethrin, allethrin and deltamethrin were 6.14, 3.10 and 2.75 times higher than those of the latter. Conclusion The insecticide resistance of Zhoushan and Hangzhou strains was generally low. None of the resistance coefficients of the two strains was higher than 10 to any of the insecticides except deltamethrin. Each of the resistance coefficients of Zhoushan strains was higher than the counterpart of Hangzhou strains except for dichlorvos
Objective To determine the dynamics of the resistance of outdoor natural populations of Musca domestica to six insecticides including deltamethrin in seven cities such as Ningbo, providing the basis for scientific and proper use of pesticides and further development of fly control. Methods Topical application was used to determine the median lethal dose of the agents to M. domestica. Results The natural populations of M. domestica in the seven cities were most resistant to deltamethrin and beta cypermethrin, the resistance ratios for which were: 34.9 and 22.6 times in Ningbo, 38.6 and 20.8 times in Lishui, 36.4 and 23.5 times in Wenzhou, 28.3 and 30.5 times in Quzhou, 40.1 and 36.1 times in Jinhua, 34.1 and 32.0 in Shaoxing, and 37.9 and 20.4 times in Linhai. The resistance ratios for dichlorvos and cypermethrin, to which the flies were less resistant, were: 10.3 and 15.7 times in Ningbo, 10.9 and 12.5 times in Lishui, 11.2 and 17.5 times in Wenzhou, 13.8 and 12.6 times in Quzhou, 14.3 and 11.2 times in Jinhua, 10.7 and 16.3 times in Shaoxing, and 15.2 and 10.9 times in Linhai. The resistance ratios of the flies in Quzhou and Jinhua to permethrin were 10.1 and 13.0 times, respectively, while all of those in the other five cities were below 8.2 times. The resistance ratio of all the flies to while acetophenate was below 1.9 times. Analysis of variance showed significant difference in the resistance between the natural populations of M. domestica in the seven cities and the susceptible lines (F＝ 51.299, P＝0.000), though no statistical difference was found in the resistance between the natural populations from different regions (F＝0.100, P＝0.998). Analysis of variance showed statistical difference in the varied insecticidal resistance of the natural populations to different agents (F＝25.420, P＝0.000). Conclusion The natural populations demonstrated varied resistance to the 6 pesticides, and were most resistant to deltamethrin and beta cypermethrin.
Objective To compare the effectiveness of the labor-hour method and the light trap method to mosquitoes, providing the basis for development of scientific and standard mosquito monitoring. Methods The study was conducted in Ningbo, where adult mosquitoes were monitored using the light trap method on a monthly basis to identify the composition and seasonal dynamics of mosquitoes. The resulting data were compared with the monitoring results from 2006 through 2008 based on the labor hour method. Results According to the labor-hour monitoring results, Culex pipiens pallens was the predominant indoor species in the residential areas of the city from 2006 to 2008, accounting for 99.17% of total mosquitoes. Aedes albopictus, Anopheles sinensis and Cx. tritaeniorhynchus accounted for 0.49%, 0.20% and 0.13%, respectively. The light trap monitoring in residential areas showed that Cx. pipiens pallens accounted for 81.55% of the total number, while Cx. tritaeniorhynchus, An. sinensis and Ae. albopictus accounted for 13.43%, 2.31% and 1.97%, respectively. Conclusion Both kinds of approaches were useful in revealing the composition of predominant mosquito species in the region. Therefore, the light trap method, featuring ease of use and minimum man-made factors, is more suitable for long-term systematic monitoring.
Objective A network system with electronic warning functions was developed for monitoring and control of regional termite infestation, providing a new technique and approach for termite control in China. Methods The electronic monitoring and control devices were planted in the areas of active termites to assess the reliability of infestation alarms made by the devices. Results The infestation warning network system based on type B monitoring and control devices provided accurate warnings in terms of the infestations of common termites such as Coptotermes formosanus, Reticulitermes speratus and Odontotermes formosanus. Conclusion The electronic warning network system for termite monitoring and control may be used for the termite prevention and control in housing construction, reservoirs, dams and landscaping and greening.
Objective To describe the symptoms and morphologic characteristics of Culex pipiens quinquefasciatus infected with Entomophaga conglomerata, providing the basis for mosquito control. Methods Samples were stained with aceto- orcein for observation of the morphology of E. conglomerata. Microscopic measurements of the diameters of conidia, nuclei and conidiophores were made followed by photography. Results Adults of Cx. pipiens quinquefasciatus infected with E. conglomerata floated on water and ventrally bent to form a C shape with wings laterally open at about 90°. The abdomen of corpses swelled with distinct white rings due to formation of hymenium from the intersegmental membranes. Branches were not present in the conidiophores of E. conglomerata; the primary conidia were pyriform to round, single-wall, multi-core, and easily stained by aceto- orcein. Dormant spores, pseudocysts and rhizoids were not observed. Conclusion Though not previously reported, the infection of E. conglomerata in Cx. pipiens quinquefasciatus may be potentially essential to the control of this mosquito species.
Objective To evaluate the effects of different vector mosquito control measures for malaria in Yongcheng through field tests. Methods Vector monitoring was conducted in villages using different vector prevention and control measures, where mosquitoes of anopheles were captured every ten days using 50 mosquito nets indoors in early morning and using human baits outdoors at night. Results A total of 79 anopheles mosquitoes were captured by nets in early morning, accounting for 33.33%, with other captives of 158 accounting for 66.67%. The average anopheles density was 0.18/net per capture in the control group, and 0.03, 0.03, 0.05 and 0.06/net per capture in the impregnated-net group, residual spraying group, impregnated-net plus larviciding group and residual spraying plus larviciding group, respectively. Albeit effective in reducing anopheles density (F＝ 4.553，P＜0.01), these measures were not deemed different in the effects. The average man-biting rate was 0.10 mosquito/(person· night) in the control group, and 0.02, 0.01, 0.03 and 0.03 mosquito/(person·night) in the impregnated-net, residual spraying, impregnated - net plus biological larviciding and residual spraying plus larviciding groups, respectively. Though effective in reducing man-biting rates (F＝5.261，P＜0.01), the measures were not considered different in the effects. At different monitoring sites, 183 anopheles mosquitoes were captured outdoors by human baits at night, accounting for 15.69%, with other captives of 983 accounting for 84.31%. The average anopheles density was 2.48/h in the control group, and 0.76, 2.12, 0.24, 1.08 and 0.64/h in theimpregnated-net, residual spraying, biological larviciding, impregnated-net plus larviciding and residual spraying plus larviciding groups, respectively. The mosquito density in the impregnated-net, biological larviciding, impregnated-net plus larviciding and residual spraying plus larviciding groups was lower than that in the control group, and the density in the residual spraying group was higher than those in the impregnated-net, biological larviciding and residual spraying plus larviciding groups. The average man- biting rate was 12.40 mosquitoes/(person·night) in the control group, and 3.80, 10.60, 1.20, 5.40 and 3.20 mosquitoes/(person· night) in the impregnated-net, residual spraying, biological larviciding, impregnated-net plus larviciding and residual spraying plus larviciding groups, respectively. The man - biting rates in the impregnated - net, biological larviciding, impregnated - net plus larviciding and residual spraying plus larviciding groups were lower than that in the control group, while the rate in the residual spraying group was higher than those in the impregnated net, biological larviciding and impregnated-net plus larviciding groups. The Pearson correlation analysis revealed a positive correlation between the outdoor anopheles density in October and the incidence of malaria in November (r＝0.945，P＜0.01), and a positive correlation between the corrected man-biting rate in October and the incidence of malaria in November (r＝0.927，P＜0.05). Conclusion The above prevention and control measures were effective in reducing both indoor and outdoor anopheles density as well as man-biting rates in Yongcheng city; however, the advantages and disadvantages of specific measure should be further studied.
Objective To identify the prevalence of ticks infected with spotted fever group rickettsiae in mountain areas of Zhejiang province, and to explore the feasibility of the PCR approach using rickettsial outer membrane protein A (rOmpA) and citrate synthase (gltA) gene as the target genes. Methods The rOmpA and gltA gene specific fragments were assessed using the PCR method from 46 tick specimens in Tiantai Zuoxi county and Lin’an Xitianmu region. The positive samples were cloned and sequenced followed by cluster analysis. Results The rOmpA and gltA gene specific fragments of spotted fever group rickettsiae were detected from 2 Haemaphysalis longicornis of the 46 specimens, with similar nucleic acid sequences. However, the evolutionary positions of the spotted fever group rickettsia species were presumably different between the two. Conclusion The ticks infected with spotted fever group rickettsiae were found in some mountain areas of Zhejiang province. Spotted fever group rickettsiae were detected from the
Objective To compare and analyze the monitoring results of three different types of malaria in the corresponding endemic areas in Guangxi Zhuang Autonomous Region (Guangxi) from 1999 to 2008, so as to evaluate the monitoring measures and provide the basis for category control and prevention. Methods Fever cases of local residents, floating population and indirect immunofluorescence antibody (IFA) assay results in 51 counties within the endemic areas of three different patterns of malaria in Guangxi from 1999 to 2008 were collected for descriptive analysis. Results The plasmodium positive rate in the blood of local fever patients in the three kinds of malaria-endemic area (12 counties on the Guizhou-Guangxi border, 8 counties on the Sino- Vietnamese border and 31 malaria-free counties) were 0.0148% (215/1 450 957), 0.0015% (12/811 810) and 0 (0/276 859), respectively; the positive rate of returned emigrants were 3.1532% (360/11 417), 2.0206% (290/14 352) and 0.2865% (424/148 008), respectively; and the those of immigrants were 0.1710% (85/49 699), 0.1955% (31/15 860) and 0.0899% (70/77 856), respectively. A total of 1487 cases of malaria were detected; local infected patients accounted for 15.27% (227/1487), returned emigrant patients accounted for 72.23% (1074/1487), and immigrant patients accounted for 12.51% (186/1487). The IFA positive rates for the focal groups in the three patterns of malaria-endemic area were 0.3078% (102/33 134), 0.2392% (69/28 843) and 0.0283% (37/130 828), respectively. Conclusion The annual incidence in the endemic areas of three patterns of malaria in Guangxi was controlled below one per ten thousand. The local transmitted cases were concentrated mostly in the 12 counties on the Guizhou-Guangxi border and the 8 counties on the Sino-Vietnamese border, whereas no cases were found in the 31 malaria-free counties. The antibody levels of the population were consistent with the degree of malaria prevalence. Therefore, the monitoring and control of the three patterns of malaria in the corresponding endemic areas should be further strengthened.
A total of 57 species, 34 genera of Sarcophagidae in Guangdong and Hainan were identified, including 44 species in Guangdong and 25 in Hainan. Robineauella walayari (Senior-White) was a newly recorded species in China, in addition to other thirteen newly recorded species from Guangdong and two from Hainan. Sinonipponia hainanensis (Ho) was first recorded in Hong Kong. The flesh flies in Guangdong and Hainan were mostly of the subfamily Sarcophagidae.
Objective A computer program was developed based on the internationally recognized statistics analysis system(SAS) to rapidly screen for the optimal synergistic formula for pesticide formulations. Methods Agents A and B were combined in a certain ratio and subject to the determination of toxicity against Tetranychus cinnabarinus and the computer program calculations for fitting the polynomial mathematical model of the co-toxicity coefficient (CTC), the arcsine transformation of the mass fraction. The derivative of the model curve was calculated and the maximum CTC and the optimal formulation ratio were computed. Results The polynomial mathematical model was statistically significant (F＝20.76, P＜0.05), the total coefficient of determination (R2)＝0.9540; the model equation was: CTC＝-2.021 499X2＋222.543 940X－5951.467 969; the derivation of the curve revealed the best extreme value X＝55.04, with the corresponding maximum CTC of 173.42 and the optimal formulation ratio of 2∶1. Conclusion Upon dual verification using program calculations, the established screening method proved to be an accurate, reliable, rapid and user-friendly approach to screen for the optimal synergistic formula.
Objective To determine the density dynamics and species composition of mosquitoes in Wanzhou agricultural areas of the Three Gorges Reservoir region, providing the basis for prevention and control of mosquito-borne diseases and mosquito hazard prediction. Methods The labor hour and light trap methods were employed to capture mosquitoes in different areas for taxonomic identification and statistical analysis. Results A total of 229 561 mosquitoes were captured using the two methods in the two years. Identification results showed that the mosquitoes were in 5 species, 4 genera, 2 subfamilies, 1 family and 1 order. The predominant species was Armigeres subalbatus, accounting for 69.80% of the total captives, followed by Culex pipiens quinquefasciatus (15.59%), Anopheles sinensis (8.56%) and Cx. tritaeniorhynchus (6.00%). The average density of adult mosquitoes in 2008 and 2009 was 247.3 and 145.8/(light·night) in residential areas, 933.5 and 1166.1/(light·night) in pigpens, and 1835.2 and 1203.3/(light·night) in cowsheds, respectively. According to the labor hour method, the average adult mosquito density was 94.03/ labor-hour in residential areas and 254.46/labor-hour in pigpens. Conclusion The density dynamics and species composition of mosquitoes obtained by the labor hour and light trap methods are the first-hand indicators of mosquitoes in Wanzhou agricultural areas and even the Yangtze River Three Gorges Reservoir region. These will be of great importance and value for the prevention and control of mosquito-borne diseases as well as vector mosquitoes in the region.
Objective To investigate the species distribution, population density, breeding habits and seasonal fluctuation of mosquitoes in Ningde, providing the basis for prevention of insect-borne diseases. Methods The investigation was conducted in compliance with the mosquito species investigation program set forth by the Fujian Provincial Center for Disease Control and Prevention. Results Mosquitoes of 47 species, 9 genera were captured from such breeding places as rice fields, rivers, water pits, bamboo zones, sewers, discarded cans and tires in Ningde. The predominant species in residential areas were Culex tritaeniorhynchus, Cx. pipiens quinquefasciatus, Anopheles sinensis and Armigeres subalbatus. The density of adult mosquitoes averaged 27.67 per labor-hour and peaked in July with a maximum of 92.00 per labor-hour. The predominant species was Cx. tritaeniorhynchus. Conclusion The species distribution, density of adult mosquitoes in residential areas and seasonal dynamics were identified in Ningde.
Objective To identify the mosquito populations and evaluate the control effects in Yuebing village and the surrounding areas of Shahe, Beijing. Methods Mosquitoes were captured using CO2 light traps and subject to taxonomic identification. Comprehensive control measures based on environmental management and chemical approaches were employed to kill mosquitoes. Results From March to October 2009, 8351 adult mosquitoes were captured, of which Culex pipiens pallens, Anopheles sinensis, Aedes albopictus and Cx. tritaeniorhynchus accounted for 99.57%, 0.19%, 0.18% and 0.06%, respectively. Cx. pipiens pallens was the predominant species. The mosquitoes emerged in early May, peaked in June and July, and generally disappeared by the end of September, mainly dwelling in woods and weeds surrounding the village. However, the mosquito density was relatively low in the village. The comprehensive control measures were simple and effective against mosquitoes. Conclusion The predominant species, seasonal dynamics and geographic distribution of mosquitoes in Yuebing village as well as the potential hazards were basically identified, which was of guiding value for anti-epidemic strategies in large-scale military activities in this region and for mosquito prevention and control in large-scale military assembly.
Objective The species, quantity and distribution of the wintering mosquitoes in Dongcheng district were investigated to provide data basis for early forecast, prediction and handling of emergency events. Methods The wintering mosquitoes were monitored by visual observation. Five observation places were randomly selected from the monitoring sites,1m2 for each, to record the number of mosquitoes within 5 min. In the process, priority was given to the monitoring in the major habitats for overwintering mosquitoes such as air-raid shelters, basements and greenhouses. Results Wintering mosquitoes had been observed for two consecutive years, and were identified as Culex pipiens pallens in both years. In 2008, a total of 31 monitoring sites were set up, covering a cumulative monitoring area of 5600 m2, resulting in a positive rate of 19.35%. In 2009, 26 monitoring sites were set up with the cumulative area of 2835 m2, resulting in a positive rate of 15.38%. The number of winter mosquitoes significantly increased in 2009 as compared to that in 2008, the average mosquito density being 0.88 per m2 in the former and 0.41 per m2 in the latter. The number of wintering mosquitoes in air-raid shelters remained high for the two consecutive years with the average mosquito density of 3.50 and 6.25 per m2, respectively. Conclusion Air-raid shelters were the major habitat for wintering mosquitoes. The monitoring of mosquito and the prevention and control of related infectious diseases in the next summer should be strengthened.
Objective To identify the baseline species composition and distribution patterns of ticks and their parasitic relationships with the host animals at Atlataw Pass, and to monitor the dynamics of border-crossing ticks, providing the basis for identification of alien species and disease transmission. Methods From January to December 2008, ticks were collected manually or by using clothes from livestock, poultry, wild animals, small mammals and caves at plague monitoring sites along Alataw Pass. The predominant populations were monitored for pathogens. Results After one-year investigation, 1780 ticks of 8 species in 5 genera, 1 family were collected, including 334 found on imported cowhide. The predominant species was Hyalomma asiaticum, accounting for 78.8%. These ticks were distributed in each monitoring site except urban areas, and also the ones primarily parasitic on the surface of domestic animals and small mammals. Other common species of tick included Dermacentor niveus, Hy. detritum, Hy. scupense and Haemaphysalis erinacei. The first 3 were mainly seen on the surface of such animals as cattle, sheep, horses and camels, while the other in small animals such as Vormela peregusna and Hemiechinus auritus. Rare species consisted of Ixodes redikorzevi and Rhipicephalus sanguineus, which were mainly found on the surface of wolves and in rat holes. Rh. pumilio was the strange species collected. A total of 334 ticks were detected on imported cowhide. Conclusion The one - year investigation revealed the baseline species composition, distribution and seasonal dynamics of vector ticks and their parasitic relationships with the host animals along Alataw Pass, as well as tick infestation on imported cowhide. This study provided the basis for prevention and control of tick-borne diseases and the spread of this
Objective To determine the resistance of Rattus tanezumi to warfarin and bromadiolone in Changsha city where anticoagulants were not frequently used. Methods A non-selective feeding trial was conducted using 0.025% warfarin and 0.005% bromadiolone baits. Results After 18 days’application of 0.025% warfarin and 0.005% bromadiolone baits, dosage, the occurance rate of warfarin-resistant R. tanezumi was 43.48% (10/23), and that of bromadiolone-resistant ones was 21.21% (7/33). Conclusion Resistance of R. tanezumi to warfarine and bromadiolone still exists in Changsha city where anticoagulants were not frequently used in recent years.
Objective To determine the resistance of the natural populations of Culex pipiens quinquefasciatus and Musca domestica to commonly used pesticides in Lishui, providing the basis for proper insecticidal administration and development of mosquito and fly control. Methods The drug immersion method was employed to measure the median lethal concentration for fourth-instar larval mosquitoes, and topical application was conducted to determine the half lethal dose for the adult flies. Results The resistance ratios of the natural populations of Cx. pipiens quinquefasciatus to BPMC and acetophenate were at a low level close to those of susceptible lines; and the ratios to deltamethrin, permethrin, beta cypermethrin and dichlorvos were 9.0, 5.5, 5.4 and 4.8 times, respectively. The resistance of the natural populations of M. domestica was at a low level to acetophenate, tetramethrin and permethrin, an intermediate level to dichlorvos (10.9 times) and a high level to beta cypermethrin (20.8 times) and deltamethrin (38.6 times). Conclusion The natural populations of flies and mosquitoes had varied resistance to the 7 insecticides in Lishui.
Objective To determine the feeding habits of Spermophilus dauricus Brandt in the north frontier administration areas of Hebei province, providing the basis for plague prevention and control as well as rodent damage assessment. Methods The S. dauricus Brandt of different habitats were captured and randomly sampled by male, female, adult and infant. The subjects’stomachs were weighed, and dissected for analysis of the contents and respective proportion of the components. Results The average stomach weight was 10.48 g, and the maximum was 40.50 g. A total of 80% of the sample stomachs contained mainly the green parts of plants, 7% contained mainly seeds and rootstalks, and 9% contained mostly insects. Different composition of the stomach contents was noticed between June and July and between adults and infants, albeit not found between males and females. Conclusion S. dauricus Brandt has a big appetite and intakes mainly vegetable foods, including agricultural crops and the green parts of pasture, and often insects, seeds and rootstalks. The food composition varies with environment.
Objective To analyze the results of plague surveillance on the periphery of Batang Airport in Yushu in order to provide the basis for development of the control and prevention strategies against plague spread by air transport. Methods Field research was conducted at Batang civil airport; dynamics of plague in Yushu and the plague surveillance data of the past three years in Batang were systematically analyzed. Results All of the six counties within Yushu Prefecture were natural foci of plague. With severe prevalence of plague, Yushu witnessed continued outbreaks of plague in animals year after year, which also spread to mankind occasionally. Batang Airport was located in a natural focus of plague where three interanimal plagues had been detected from 2007 to 2009, with 4 pathogenic strains isolated. Conclusion Risks of interanimal plague were identified on the periphery of Batang Airport, where the disease might be spread through aircrafts. The airport should set up its health quarantine mechanisms and system according to the Regulations on Domestic Communications Health Quarantine, and implement transport quarantine and operate pursuant to law.
Objective To determine the epidemiological characteristics of scrub typhus in Panzhihua city, providing the basis for development of targeted prevention and control measures. Methods Descriptive epidemiological approaches were employed to analyze the spatial and temporal distribution of 255 scrub typhus patients reported via the Chinese Disease Prevention and Control Information System in Panzhihua city from 2006 through 2008. Results The largest number of reported cases was present in 2008, accounting for 58.4% of the 255 cases. With peaking incidence rates from June to October, the cases in this period accounted for 89.4% of the total number. Most cases were from rural areas, accounting for the 96.9% of the reported number throughout the city, of which those from Miyi accounted for 59.6%. Patients were noticed in all age groups, though most were adults over 19 years of age, accounting for 68.6%. Farmers were the primarily affected occupation, accounting for 67.5%, followed by students and young children, accounting for 14.5% and 13.7%, respectively. Suspected cases constituted the largest reported portion, accounting for 52.2%, followed by clinically diagnosed ones, accounting for 45.5%; only 6 cases were confirmed through laboratory diagnosis. Most reporting institutions were at county-level, accounting for 62.4%，followed by municipal and town-level ones, accounting for 23.5% and 14.1%, respectively. Conclusion In view of the noticeable seasonal and regional dynamics of the incidence of scrub typhus and the primarily affected group, farmers, in Panzhihua city, the prevention and control measures should be focused on the rural areas in summer and autumn.
Objective To determine the epidemiological characteristics of brucellosis and the influential factors in Qinghai, providing the basis for development of the prevention and control strategies. Methods Descriptive epidemiological analysis was conducted in such fields as the onset year, region and seasonal transmission factors. Results Of the 1543 sera samples, 129 positives were detected by the rose bengal plate agglutination test, with a positive rate of 8.36%; 38 positives were found by the tube agglutination test, with a positive rate of 2.46%. A total of 17 new emerging cases were reported in Qinghai from 2006 to 2008. The incidence peaked from March to July. Pastoralists were primarily affected. Conclusion The human brucellosis prevalence existed in Qinghai and was characterized with spring-to-summer peak and pastomlist-predominant.
Timely, accurate prediction and forecast of malaria epidemic is critical to malaria control. The application of geographic information systems in malaria control provides a strong technical support for the field investigation of malaria, and saves precious time for decision-makers to develop appropriate prevention strategies to reduce social and economic losses. Therefore, geographic information systems are playing an increasingly important role in malaria control in recent years.
The natural focus of Marmota himalayana plague on Qinghai-Tibet plateau is one of the most active plague foci in China. In particular, since the beginning of the 1990s, epizootic epidemics have continually emerged year after year in conjunction with regional outbreaks, occasionally affecting human beings. This paper systematically analyzes the geographical characteristics of the focus of M. himalayana plague on Qinghai-Tibet plateau, prevalence patterns of animal and human plagues, etiologic characteristics of plague and current status of plague surveillance, providing the basis for further development and adjustment of the prevention and control strategies.
This study introduces the origin of plague and analyzes the persistence of Yersinia pestis (plague bacillus) in the natural foci of plague. By describing the epidemiologic characteristics of epizootic plague and the revelatory elimination of plague origins in the 1970s, the study depicts the advancement in the research into the mechanisms of persistence of Y. pestis in nature, and raises a new hypothesis that during plague-free intervals, Y. pestis is preserved in nature through gene mutations on a long-term basis, forming a Y. pestis-host-vector trinity ecosystem.
Lucilia sericata is a common medical vector insect in the subfamily Calliphorinae of the family Calliphoridae, under the order Diptera. It mechanically transmits diseases and causes myiasis, while its necrophagy also contributes great practical value to environmental decontamination and forensic entomology. In recent years, progress has been made in the study of issues such as the nutritional content of L. sericata, induction of the larvae to produce antibacterial substances and application of the larvae in wound healing. This paper outlines the domestic and international researches relating to the feeding, biological characteristics, experimental ecology, prevention and application of L. sericata, and discusses the direction of future research, providing the basis for further study of this insect.
Objective To summarize the integrated rodent control measures in large-scale supermarkets by investigation and analysis of the cause of rodent damage therein. Methods The bait and trap methods were employed to capture rats for analysis of rodent palatability, density and population distribution. The powder trace method was used to evaluate the deratization effect. Results Rattus norvegicus was the predominant rodent species in large-scale supermarkets; apples were most palatable to the rats. The positive rate of rodent traces was 36.51% before the implementation of integrated control measures, and dropped to 0 after three months of rodent control, with a deratization effect of 100%. No rodent trace blocks were found in the following three consecutive months. Conclusion The integrated control measures were effective in rodent control.
