Epidemiological Predicting of the Fleas on Rattus norvegicus

[Objective]To predict prevalence of fleas via a simple epidemiological model.[Method]The field investigation was carried out in 23 locations in Yunnan Province.A simple epidemiological model was involved mean abundance and variance of abundance.[Result]The prevalence of fleas increased with their mean abundance in logistic curve.A linear correlation of the predicted prevalence against observed prevalence did not differ significantly from unity.[Conclusion]Prevalence could be explained simply by their mean abundance.

Comparison of Two Pour-On Formulations of Ivermectin against Gastrointestinal Worms, Fleas and Lice in Naturally Infected Stray Dogs

The aim of the present study was to evaluate the efficacy of two commercial pour-on ivermectin formulations against intestinal parasites (IP), fleas and lice in naturally infested stray dogs. Eighteen crossbreed dogs with eggs of IP as well as adult fleas and lice were included in the trial. On day 0, the dogs were randomly divided into 3 groups of 6 animals each: a group receiving a single pour-on treatment with 0.5% ivermectin (500 mcg/kg), a group treated similarly with 0.2% iver-mectin (200 mg/kg), and a control group. Fecal and skin analyses were carried out on days 0, 7, 14, 21 and 28 to determine the reduction of eggs and the number of fleas and lice. Weight gain was also measured on day 28. On day 30, the dogs were humanely sacrificed in order to count adult IP. Efficacy was measured as the percentage of the reduction of eggs per gram fecal mass (EPGF), of adult IP, fleas and lice relative to the control group. For the eggs of IP, ivermectin at 0.5% showed an efficacy of 100% against ascarids and 79% against Ancylostoma caninum. ivermectin at 0.2% removed 90.2% of the ascarids and 50.4% of A. caninum. For adult IP, the efficacy of 0.5% iver-mectin against Toxocara canis and A. caninum was 100%, and for 0.2% ivermectin it was 62.4% and 76.4% for T. canis and A. caninum, respectively. Both compounds were 100% effective against lice and 96% and 71.1% efficacious against fleas, respectively. However, neither treatment was effective against Dypilidium caninum. Weight gain in treated dogs was statistically different from that of the controls (p < 0.05). We concluded that 0.5% pour-on ivermectin showed better efficacy than 0.2% pour-on ivermectin in the reduction of eggs and adult intestinal parasites and fleas;it was similarly efficacious against lice.

Comparative Efficacy of Three Commercial Ectoparasiticides against Fleas in Naturally Infested Dogs

Fleas that infest pets are considered important parasites of both animals and humans. These insects cause irritation and can also transmit zoonotic diseases. Research has led to a rapid expansion in the development of flea control products. In the face of a market that offers dozens of commercial ectoparasiticides for dogs and cats, pet owners and veterinarians must be provided with evidence to support their decision to select a product to control fleas. To compare the efficacy of three commercially available products against companion animal fleas, a trial was conducted on naturally-infested dogs in order to validate their pulicidal activity. Thirty-two flea-infested dogs with fleas were divided into 4 groups (n = 8) for each treatment. Group 1 received one pipette of permethrin as a spot-on dose of 650 mg/ml. The second group received 9.7% fipronil as a spot-on formulation. Group 3 was treated with a spot-on formulation of permethrin 7.40% plus piperonyl butoxide at 7.40%. Group 4 remained as the untreated control. Fleas of all experimental dogs were examined and counted on days 0, 3, 7, 14, 21 and 28 to determine the percentage of flea reduction. Results showed a 100% efficacy for all tested products. Identified species were: Ctenocephalides felis (75.7%), Ctenocephalides canis (15.9%) and Pulex irritans (9.5%). Based on these results, it was concluded that the three anti-flea products evaluated under the conditions of this study, produced an excellent efficacy as from the third day after treatment.

The combined effect of bromadiolone and ivermectin (iBr) in controlling both rodents and their fleas

Rodent pests not only cause severe agricultural loss but also spread zoonotic pathogens to human beings.Antico-agulant rodenticides are widely used to decrease the population densities of rodents but often lead to the spillover of ectoparasites becausefleas and ticks may gather on surviving rodents.Therefore,it is necessary to killfleas and ticks before culling rodents to minimize the risk of pathogen transmission.In this study,we used a mixture of ivermectin(an antiparasitic drug)and bromadiolone(an anticoagulant rodenticide)to control both rodent andflea/tick abundances.We found that in a laboratory test,0.01%ivermectin bait was not lethal for greater long-tailed hamsters after 7 days of treatment,while 0.1%ivermectin bait was lethal for approximately 33%of treated rodents.In afield test,bait containing 0.001%,0.005%,0.01%,and 0.05%ivermectin decreased the number offleas per vole of Brandt’s voles to 0.42,0.22,0.12,and 0.2,respectively,compared with 0.77 in the control group,indicating that 0.01%ivermectin bait performed best in removingfleas.In another laboratory test,bait containing a 0.01%ivermectin and 0.005%bromadiolone mixture caused the death of all voles within 6–14 days after the intake of the bait.In thefield test,the bait containing 0.01%ivermectin and 0.005%bromadiolone reduced the average number offleas per vole to 0.35,which was significantly lower than the 0.77 of the control group.Our results indicate that a 0.01%ivermectin and 0.005%bromadiolone mixture could be used to control both rodents andfleas to minimize the spillover risk of disease transmission when using traditional rodenticides.

Latitudinal gradients in body size and sexual size dimorphism in fleas:males drive Bergmann’s pattern

We tested for the effects of latitude and geographic range size(GRS)on body size,leg length,and sexual size dimorphism(SSD)across 103 species offleas,taking into account phylogenetic between-species relationships.When the data on body size were combined for males and females,the positive correlation between body size and latitude,but not GRS,was revealed.When the analysis was restricted to one sex only,the effect of latitude appeared to be non-significant for females,whereas male body size increased with an increase in latitude.Intraspecific body size variation was not associated with either the latitude or the latitudinal span of the geographic range,independently of which data subset was analyzed.No evidence of association between size-independent tibia length and latitude was found for either females,males,or both sexes combined.The degree of SSD decreased with a decrease in latitude but was not affected by GRS.We conclude that macroecological patterns might be manifested differently in males and females.This should be kept in mind while searching for these patterns.

Predictors of the abundance of small mammals' parasitic fleas in households of Western Yunnan Province

Objective To analyze the predictors of the abundance of small mammals’parasitic fleas in households of Western Yunnan Province.Methods Eight hundred households of 40 natural villages from 10 counties in Western Yunnan Province were selected as study subjects.Five live-traps were placed in each household for

Seasonal and habitat dependence of fleas parasitic on small mammals in Tanzania

We investigated host and flea species composition across different habitats during dry and rainy seasons in the Western Usambara Mountains in Tanzania.During both seasons,similarity in flea species composition increased with an increase in the similarity in host species composition.Nevertheless,between-season within-habitat as well as within-season between-habitat similarity in host species composition was higher than similarity in flea species composition.Ordination of habitats according to their host and flea species composition demonstrated that the pattern of between-habitat similarity in both host and flea species composition varied seasonally.Despite the relatively rich mammal and flea fauna of the study region,the major contribution to variation in species composition between seasons and among habitats was due to a few species only.Flea assemblages on Lophuromys kilonzoi Verheyen et al.,2007 and Praomys delectorum Thomas,1910 in different habitats were equally similar in either season.In contrast,flea assemblages on Mastomys natalensis(Smith,1834)occurring in different habitats were more similar in the dry than in the rainy season,whereas the opposite was the case for fleas on Grammomys sp.In different hosts,the main differences in species composition of flea assemblages between seasons as well as among habitats were due to different flea species.Although our results support the earlier idea that parasite species composition is determined by both host species composition and habitat properties,the former appears to explain variance in flea species composition between localities in the tropics better than between localities in temperate and arid zones.

基于EP1K30TC-114的DDS的优化设计与实现

为了提高系统速率和信号质量,改善系统的可控性,降低成本,笔者利用现场可编程逻辑门阵列FPGA芯片EP1K30TC-144成功地实现直接数字频率(DDS)系统合成,阐述了DDS的原理及其在FPGA中的设计思路、优化实现方法,电路结构,给出了DDS合成的VHDL源程序,克服了专用DDS芯片的输出频带范围有限,输出杂散大等缺点.

Within-brood body size and immunological differences in Blue Tit(Cyanistes caeruleus)nestlings relative to ectoparasitism

Several ectoparasites parasitise nestlings decreasing their body condition,growth and survival.To minimise any loss of fitness due to ectoparasites,birds have developed a wide variety of defence mechanisms,potentially including hatching asynchrony.According to the Tasty Chick Hypothesis(TCH),the cost of parasitism would be reduced if ectoparasites tend to eat on less immunocompetent nestlings,typically the last-hatched chick in asynchronously hatched broods,as they are in poor body condition.Two predictions of the TCH are that immune capacity is lower in smaller nestlings than in larger ones and that parasites should provoke a more negative effect on smaller nestlings.Here,we test these predictions in a population of Blue Tits(Cyanistes caeruleus)whose broods are parasitised by Hen Fleas(Ceratophyllus gallinae)and Blowflies(Protocalliphora azurea).We recorded the presence of both ectoparasites and analysed the immunocompetence(number of leucocytes per 10,000 erythrocytes and cutaneous immune response to phytohaemagglutinin)and body condition of smaller and larger nestlings within individual broods.The leucocyte count was higher in smaller nestlings than in larger ones,whereas the cutaneous immune response did not differ between smaller and larger nestlings.Smaller nestlings,but not larger nestlings,had lower body mass when fleas were present.Blowflies,by contrast,had no detectable negative effect on nestlings.Overall,our findings provide partial support to the TCH.Lower immune capacity in smaller nestlings than in larger ones was not supported,but Hen Fleas seemed to negatively impact on smaller nestlings more than on larger ones.

直接数字频率合成器的设计

直接数字频率合成技术在数字通信系统中被广泛采用。在研究直接数字频率合成技术基本原理的基础上,基于FPGA对直接数字频率合成器进行了建模设计,通过仿真分析,证明了这种设计方法的正确性和实用性。

Are local plague endemicity and ecological characteristics of vectors and reservoirs related? A case study in north-east Tanzania

The pattern of plague endemicity in Tanzania is characterized by continuous re-appearance of the disease in some locations, while in other neighbouring villages the disease has never or seldom been observed. To understand the reasons for this pattern, we studied small mammal and flea species composition, diversity and relative abundances in two plague-endemic and two plague-free locations. We asked （a） whether fleas more abundant in plague-endemic locations differ in their characteristic abundance and the degree of their host specificity from fleas more abundant in plague-free locations and （b） whether hosts most abundant in p/ague-endemic locations differ in the diversity of their flea assemblages from hosts most abundant in p/ague-free locations. We characterized （a） each host species by species richness and degree of taxonomic relatedness of its flea assemblages and （b） each flea species by its mean abundance and size, and degree of taxonomic relatedness of its host spectrum and compared their relative abundances between locations. No significant difference between plague-endemic and plague-free locations in either host density or any variable related to flea abundance or diversity was found. However, there was marginally significant effect of taxonomic distinctness of a flea assemblage barboured by a host on its probability to be more abundant in either plague-endemic or plague-free locations. Furthermore, hosts more abundant in plague-endemic locations tended to harbour closely-related fleas. Finally, while opportunistic and specialist fleas were equally distributed in both sets of locations, fleas exploiting distantly-related hosts were found mainly in plague-free locations during the rainy season. We suggest that the observed patterns might arise due to seasonal and spatial differences in local microclimatic conditions and landscape connectivity [ Current Zoology 55 （3） ： 200 - 211, 2009].

Effect of Pest Exclusion Net(PEN)on the Sustainable Production of Late Season Broad Leaf Mustard(BLM)in Chitwan,Nepal

Broad leaf mustard(BLM)(Brassica juncea L.var.rugosa,Brassicaceae)is one of the most widely consumed vegetable crops in Nepal.The production of crop in open field is constrained by major pests like mustard aphid and flea beetle.This study was aimed to determine the effects of pest exclusion net(PEN)on pest-infestation and yield of BLM cultivar“Khumal Broad Leaf”.The experiment was carried out in randomized complete block design(RCBD)with five treatments and four replications.The treatments included control(no mulch+no net+no pesticide spray),black plastic mulch only,reflective plastic mulch only,black plastic mulch+no net+pesticide spray,and PEN+black plastic mulch+no pesticide spray.Data were analyzed with RSTAT software package and means were separated by Duncan’s multiple range test(DMRT)at 5%level of significance.The result revealed that crop under PEN had highest plant height(38.99 cm),lowest number of aphid(0-0.86 per plant),flea beetle(0-1.07 per plant)and highest total marketable yield(77.50 ton/ha)while control had lowest plant height(20.06 cm),highest number of aphid(maximum 2.49 per plant),flea beetle(maximum 2.00 per plant)and lowest total marketable yield(13.75 ton/ha).Economic analysis revealed highest benefit-cost ratio in PEN(9.90).This study indicates that the use of PEN protect BLM against aphid and flea beetle,increases yield and can be considered as a viable technology for BLM production by smallholder growers of Nepal.

An Analysis of the Readers' Roles in the Construction of Meaning in John Donne's The Flea under Reader-Oriented Theory

Among the sundry studies in China on John Donne's The Flea,there has been none done from the perspective of Reader-Oriented Theory to probe into the readers' roles in the construction of meaning.The present article under Wolfgang Iser's theories,in a further pursuit of the expansion of the gestalt of such studies on the poem,aims at exploring the readers' active roles in complementing,completing and recreating the textual meaning,and differentiating the implied reader and the actual reader through the poem as well as attempting to fulfill the construction of the reading cognitive model through the interpretation of the conceit the flea.

Extreme human annoyance caused by ctenocephalides felis felis(cat flea)

The authors report a case of human dermal complications by Ctenocephalides fills felis(cat flea)in a 28 years old woman who dwell in rural area in Mazandaran province,Iran.Furthermore,in the current report clinical manifestations,etiology and different aspects of infestation were discussed elaborately.And the importance of controlling fleas was highlighted as well.

Evaluation of a <i>Brassica napus</i>Auxin-Repressed Gene Induced by Flea Beetle Damage and <i>Sclerotinia sclerotiorum</i>Infection

Biotic stresses negatively affect canola growth and production. Flea beetle damage and Sclerotinia sclerotiorum (S. sclerotiorum) infection are two of the worst biotic stresses for canola. Auxin Repressed Proteins (ARPs) responsive to several abiotic stresses have been reported. However, information about ARPs induced by Flea beetle damage and S. sclerotiorum infection, their roles in biotic stress tolerance are still lacking in canola. ESTs for an Auxin Repressed Protein 1 (BnARP1) were highly represented (expressed) in a Brassica napus subtractive library developed after leaf damage by the crucifer flea beetle (Phyllotreta cruciferae). Expression of this gene was under different developmental control in B. napus, and it was co-induced in B. napus by flea beetle feeding, S. sclerotiorum infection, drought and cold. A total of 25 BnARP genes were represented in different B. napus stress and development EST libraries and indicated larger, diversified families than known earlier. Dwarf phenotypes, primary root growth inhibition, lateral root enhancement, reduced sensitivity to 2, 4-D, and reduced PIN1 and LOX expression in transgenic Arabidopsis expression lines suggest that BnARP1 is an auxin repressor that prevents auxin transport and supports an interaction between the auxin and jasmonate signalling pathways. And the increased survival after S. sclerotiorum infection in transgenic over-expression Arabidopsis suggests that BnARP1 could play a role in S. sclerotiorum tolerance through connecting auxin and jasmonate signalling pathways.

红辣椒乐队BASS手FLEA新添一签名款

受爵士音乐和朋克摇滚影响的天才型贝司手Flea（Michael Balzary）,作为美国摇滚乐队Red Hot Chili Peppers（红辣椒乐队）不可或缺的灵魂人物之一,他那出色的演奏风格促使红辣椒乐队走向摇滚巅峰而且重新赋予了贝司手在现代的定义。 在过去的四十年里,Flea以其独特的演奏方式为摇滚音乐带来耳目一新的景象,并激发无数贝司手在开拓新技巧时要在音色上恰当融入时髦元素。

Populational Fluctuation and Distribution of Epitrix spp.Foudras(Coleoptera:Chrysomelidae)in the Organic Tobacco Management in Santa Cruz do Sul,RS,Brazil

Among the chrysomelids, some species are considered agricultural pests, such as some representatives of Epitrix spp. Popularly known as tobacco flea, these beetles cause damage to tobacco (Nicotiana tabacum L.) by feeding on the leaf surface, causing injuries, reducing productivity and the final quality of the product to be marketed. However, studies of the biology and interactions of these individuals with the environment become essential in order to develop effective and sustainable control measures. The objective of this study was to analyze the distribution and population fluctuation of Epitrix spp., as well as to evaluate the possible influence of temperature, rainfall and adjacent vegetation on the population dynamics of this beetle in organic tobacco growing in the municipality of Santa Cruz of the South, RS. The collections were carried out weekly during the 2011/2012 harvest, using Malaise and Pit-fall traps, distributed in four points along three lines. A total of 1584 individuals belonging to the genus Epitrix were collected, and their greatest abundance was observed in late January and early February 2012 due to climatic factors, such as rainfall and temperature, favorable to the development of specimens and the tobacco leaf harvesting reduced the availability of food and conditioned a greater movement of these individuals in the crop. The results presented here are of great importance for deciding the best methodology for controlling the smoke flea, as well as knowing the influence of abiotic factors on the behavior of these organisms in the field.

Relationship between climatic factors and the flea index of two plague hosts in Xilingol League,Inner Mongolia Autonomous Region

Climatic factors are closely associated with the occurrence of vector‐borne diseases,and they also influence the distribution of vectors.The occurrence of plague is closely related to the population dynamics of fleas and their host animals,as well as climatic conditions.This study focused on Xilingol League,utilizing climatic and flea index data from 2012 to 2021.Spearman correlation and"Boruta"importance analysis were conducted to screen for climatic variables.A generalized additive model(GAM)was employed to investigate the influence of climatic factors and rodent density on the flea index.GAM analysis revealed distinct trends in flea index among different rodent hosts.For Meriones unguiculatus,the flea index declined with increased density and with higher humidity,yet rose with greater lagged sunshine duration.For Spermophilus dauricus,an initial increase in flea index with density was observed,followed by a decrease,and a rise in the index was noted when ground temperatures were low.This study reveals the nonlinear interactions and lag effects among climatic factors,density,and flea index.Climatic factors and density variably influence the flea index of two Yersinia pestis hosts.This research advances the prediction and early warning efforts for plague control,providing a theoretical basis for rodent and flea eradication strategies.

Rodent control to fight plague:field assessment of methods based on rat density reduction

Rodents represent a serious threat to food security and public health.The extent to which rodent control can mitigate the risk from rodent-borne disease depends on both the effectiveness of control in reducing rodent abundance and the impact on disease epidemiology.Focusing on a plague-endemic region of Madagascar,this study compared the effectiveness of 3 methods:live-traps,snap-traps,and rodenticides.Control interventions were implemented inside houses between May and October 2019.Tracking tiles monitored rodent abundance.Rodent fleas,the vector involved in plague transmission,were collected.Rodent populations consisted of Rattus rattus and Mus musculus.In terms of trap success,we found that our live-trap regime was more effective than snap-traps.While all 3 control strategies appeared to reduce in-house rodent activity in the short term,we found no evidence of a longer-term effect,with in-house rodent abundance in treated sites comparable to non-treatment sites by the following month.Endemic flea,Synopsyllus fonquerniei,is a key plague vector usually found on rats living outdoors.Although we found no evidence that its abundance inside houses increased following control,this may have been due to a lack of power caused by significant variation in S.fonquerniei abundance.The presence of S.fonquerniei in houses was more likely when S.fonquerniei abundance on outdoor rats was higher,which in turn correlated with high rat abundance.Our results emphasize that control strategies need to consider this connectivity between in-house rat–flea populations and the outdoor populations,and any potential consequences for plague transmission.

Temporal and spatial distribution characteristics in the natural plague foci of Chinese Mongolian gerbils based on spatial autocorrelation

Background:The nest flea index of Meriones unguiculatus is a critical indicator for the prevention and control of plague,which can be used not only to detect the spatial and temporal distributions of Meriones unguiculatus,but also to reveal its cluster rule.This research detected the temporal and spatial distribution characteristics of the plague natural foci of Mongolian gerbils by body flea index from 2005 to 2014,in order to predict plague outbreaks.Methods:Global spatial autocorrelation was used to describe the entire spatial distribution pattern of the body flea index in the natural plague foci of typical Chinese Mongolian gerbils.Cluster and outlier analysis and hot spot analysis were also used to detect the intensity of clusters based on geographic information system methods.The quantity of M.unguiculatus nest fleas in the sentinel surveillance sites from 2005 to 2014 and host density data of the study area from 2005 to 2010 used in this study were provided by Chinese Center for Disease Control and Prevention.Results:The epidemic focus regions of the Mongolian gerbils remain the same as the hot spot regions relating to the body flea index.High clustering areas possess a similar pattern as the distribution pattern of the body flea index indicating that the transmission risk of plague is relatively high.In terms of time series,the area of the epidemic focus gradually increased from 2005 to 2007,declined rapidly in 2008 and 2009,and then decreased slowly and began trending towards stability from 2009 to 2014.For the spatial change,the epidemic focus regions began moving northward from the southwest epidemic focus of the Mongolian gerbils from 2005 to 2007,and then moved from north to south in 2007 and 2008.Conclusions:The body flea index of Chinese gerbil foci reveals significant spatial and temporal aggregation characteristics through the employing of spatial autocorrelation.The diversity of temporary and spatial distribution is mainly affected by seasonal variation,the human activity and natural factors.