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the use of cattle to protect sheep from bluetongue infection.studies on the host preferences of culicoides imicola, the vector of bluetongue virus in south africa, are reviewed. there is agreement that this species prefers to feed on cattle but will also feed on other bovidae and sheep. over a seven year period cattle kept near sheep on a natal farm appear to have appreciably reduced the incidence of bluetongue in the sheep. in addition to immunization this "decoy" approach is therefore recommended to assist in the protection of stock from insect borne di ...1978215768
isolation and identification of arboviruses from the sultanate of oman.sentinel herds and a vector surveillance system were used to identify the presence of arboviruses in oman. two strains of bluetongue virus (btv) serotype 4 and two strains of akabane virus, were isolated and identified. both btv isolates and one akabane virus isolate came from goats while the second akabane isolate came from culicoides imicola. this is the first isolation of an akabane virus from culicoides in arabia. vector competence studies with the oman viruses in laboratory reared c. variip ...19911850363
further studies on bluetongue and bluetongue-related orbiviruses in the sudan.the seasonal incidence of bluetongue virus (btv) in central sudan is related primarily to fluctuations in the prevalence of the vector, culicoides imicola. population densities of this midge begin to rise with the onset of precipitation and peak during october, before falling sharply at the end of the rainy season in november. these are also the months of btv transmission. populations of c. schultzei, the commonest midge in central sudan, are also related to the rainy season but this species doe ...19902174372
[current information on the subject of african horse sickness (ahs)].the objective of the present review was to summarize current knowledge of african horse sickness (ahs), based on available literature (which is nonetheless relatively scant) and recent information obtained from the o.i.e. brief description is made of the biology of ahs virus (an arbovirus, transmitted by culicoides imicola), isolation of the agent, diagnosis by serotyping procedures, and preventive measures (such as protection of horses from insect infestation, or vaccination programs) which may ...19902193386
immunogenicity and allergenicity of culicoides imicola (diptera: ceratopogonidae) extracts.summer seasonal recurrent dermatitis (ssrd) or "sweet itch" is a seasonally occurring allergic dermatitis of horses provoked by biting midges. the allergic skin reactions have been attributed to allergens present in various culicoides species. c. imicola is the suspected etiological agent of ssrd in israel. whole body extracts of this midge induced hypersensitivity reactions upon injection into susceptible horses and in this study attempts were made to define components of c. imicola which have ...19902346072
potential of infra-red thermography for the detection of summer seasonal recurrent dermatitis (sweet itch) in horses.the feasibility of using infra-red thermography for early and out of season detection of summer seasonal recurrent dermatitis (sweet itch) was tested on 13 sensitive and six insensitive horses in israel. in summer (june, july and september) six affected mares and two unaffected sensitive mares (one of them a pony) were clearly 'warmer' in the affected zones than three insensitive mares. in winter (february and march) unaffected sensitive horses could be differentiated from insensitive mares by t ...19892815515
further data on the distribution of biting midges in southern europe and the mediterranean area, with special reference to culicoides imicola.studies on the culicoides midges of spain and turkey suggest that the range of c. imicola may extend to about 40 degrees n. however, catches of midges from mainland greece, sicily and italy failed to reveal the presence of this species. these findings are discussed in the light of the possibility of the occurrence of bluetongue (bt) disease in these areas, consequent upon windborne spread of infected vectors from countries where the disease is endemic.19852989851
isolation and propagation of bluetongue virus in embryonating chicken eggs.the incidence of bluetongue (bt) disease in sheep in israel during 1964-1982 was presented. the intravenous (iv) and the yolk-sac (ys) routes of inoculating embryonating chicken eggs (ece) for primary isolation and propagation of bt virus (btv) were compared and assessed. it was shown that the iv route of inoculation was about 100- to 1,000-fold more sensitive than the ys route; also, by the iv route, virus isolation was more rapid and assays were more clear cut. about 30% of virus isolations fr ...19852989868
culicoides imicola: a bluetongue virus vector in spain and portugal. 19852990083
epidemiological and immunological studies of sweet itch in horses in israel.a survey of sweet itch in horses in israel based on a questionnaire to owners reported that 158 of 723 horses (21.8 per cent) had sweet itch lesions. the results indicated that the likelihood of a horse acquiring sweet itch decreased with increasing altitude but no definite association with rainfall zones was evident. variation in the density of the horse population, however, obscured these observations. in the population surveyed, stallions were more sensitive than mares and pale horses appeare ...19836879963
the virtual absence of culicoides imicola (diptera: ceratopogonidae) in a light-trap survey of the colder, high-lying area of the eastern orange free state, south africa, and implications for the transmission of arboviruses.altogether 52 078 culicoides biting midges of 35 species were collected during february 1990 and 1993 in 40 light-trap collections made on 17 cattle and/or sheep farms in the bethlehem and fouriesburg districts of the colder, high-lying eastern orange free state. culicoides (avaritia) bolitinos was by far the most abundant species, representing 50.9% of all specimens collected. culicoides (a.) imicola, considered to be the most common stock-associated species in the summer rainfall areas of sout ...19947501364
presence of culicoides imicola (diptera: ceratopogonidae) in jaen, spain.culicoides imicola kieffer is reported from 2 locations in the province of jaen, spain. the locations are outside the area where african horse sickness epizootics occurred from 1988 to 1990. the absence of african horse sickness in jaen during this period may have been due to the low abundance of this species.19947807099
fecundity and proportions of gravid females in populations of the bluetongue vector culicoides imicola (diptera: ceratopogonidae) and several other species in israel.the gravid proportions of five culicoides spp. in israel were determined based on a suction light trap placed above calves in a cowshed and on two similar traps hung in a eucalyptus tree at elevations of 1.4 and 26 m. in the cowshed, the proportion of gravid culicoides distinctipennis austen showed no significant variation between seasons; c. imicola kieffer (the dominant species) was caught in significantly smaller proportions in winter; c. schultzei gp (second most dominant) showed no signific ...19947815395
african horse sickness and the overwintering of culicoides spp. in the iberian peninsula.the presence at different latitudes and the seasonal distribution of two known or potential vectors of african horse sickness (ahs) virus--culicoides imicola and c. obsoletus--were investigated in the iberian peninsula using light trap collections. culicoides imicola was present as far north as 41 degrees n but not at 43 degrees n (asturias, spain), whereas c. obsoletus was found at all latitudes. in the northern part of the distribution of c. imicola, adults of this species were present for onl ...19947949350
epizootiology and vectors of african horse sickness virus.african horse sickness (ahs) virus causes a non-contagious, infectious, arthropod-borne disease of equines and is enzootic in sub-saharan africa. the major vectors are species of culicoides but mosquitoes and ticks may be involved. periodically the virus makes excursions beyond its enzootic zones but until recently has not been able to maintain itself outside these areas for more than 2-3 consecutive years. this is probably due to a number of factors including the absence of a long term vertebra ...19948001350
preliminary note on the distribution and ecology of culicoides imicola in portugal.data on culicoides imicola were obtained during studies carried out during the recent outbreak of african horse sickness in portugal. the previous most northerly published record of c. imicola in portugal was 38 degrees 40'n (pégöes). in the present work the geographical distribution of this species is extended to the parallel of 41 degrees 17'n. we have also confirmed the continuous presence of adult c. imicola in southern portugal (alentejo and algarve) throughout the year. in the laboratory w ...19938435485
role of dogs (canis domesticus) as hosts for african horse sickness virus.at bet dagan culicoides imicola kieffer, c. schultzei gp. (a mammal feeder), culex pipiens l. (a laboratory vector) and culex univittatus theobald were found in significantly (p < 0.05) smaller numbers near dogs than near other hosts, while phlebotomus spp. were found in significantly (p < 0.05) higher numbers in dog kennels than in other animal houses. some 400 blood meals of culicoides spp. from israel and zimbabwe were negative for canine blood. only 1 of 16 blood meals of culex pipiens caugh ...19968828119
ultrastructure of the eggs of culicoides circumscriptus, culicoides gejgelensis, and culicoides imicola (diptera:ceratopogonidae).the eggs of culicoides circumscriptus kieffer, culicoides gejgelensis dzhafarov, and culicoides imicola kieffer collected in israel are described and illustrated by scanning electron micrographs. eggs of all 3 species were morphologically similar, generally sausage- or cigar-shaped, with slight dorsal-ventral curvature and longitudinal rows of tubercle pillars covered with a thin adhesive layer. tubercle pillars were scarce on c. circumscriptus and c. imicola eggs, but were common on c. gejgelen ...19979152879
discovery of a culicoides imicola-free zone in south africa: preliminary notes and potential significance.in december 1993, a light-trap survey was made of the culicoides found at eight horse stables and dairies in the sandy dune field west of port elizabeth, south africa. while it was notable that culicoides numbers were low (4749) and that the diversity was poor (15 species), the most remarkable fact to emerge, was that c. imicola, the only proven vector of the virus of african horse sickness (ahs), was entirely absent. though not abundant, c. bolitinos, a sister species of c. imicola, was overwhe ...19979204508
the spatial and seasonal distribution of african horse sickness and its potential culicoides vectors in morocco.african horse sickness (ahs) is a vector-borne, infectious disease of equines that is caused by african horse sickness virus (ahsv). the only proven field vector is the biting midge culicoides imicola, although c. obsoletus and c. pulicaris are suspected vectors. there was a recent epizootic of ahs in iberia (1987-90) and morocco (1989-91). in 1994-45 a total of 3887 light trap samples were taken from twenty-two sites distributed over most of morocco. culicoides imicola was found to be very wide ...19979330250
repellency of synthetic and plant-derived preparations for culicoides imicola.the study was conducted to find a safer and longer lasting repellent for c.imicola than di-ethyl toluamide (deet), to validate whether the current recommendations in israel for application of repellents during an outbreak of disease caused by pathogens borne by culicoides imicola are justified, and to test plant-derived preparations as potential replacements for the synthetic repellents. seven repellents were compared by a method using treated netting across the entrance of a suction light trap. ...19979430115
some epidemiological and economic aspects of a bluetongue-like disease in cattle in south africa--1995/96 and 1997.in december 1995 to march 1996 and the early summer of 1997 south africa experienced above average rainfall which favoured the occurrence of culicoides transmitted diseases. during this period several outbreaks of an uncommon disease of cattle occurred over a large part of the country. the clinical signs were similar to those of infection with the viruses of bluetongue (bt) and epizootic haemorrhagic disease of deer (ehd). virus isolation from cattle and culicoides yielded both viruses. dual inf ...19989809318
mosquito repellent attracts culicoides imicola (diptera: ceratopogonidae).a plant-derived mosquito repellent, based on the oil of eucalyptus maculata var. citriodora hook, was evaluated against the biting midge culicoides imicola kieffer. suction black light-traps covered with repellent-impregnated polyester mesh and deployed near horses attracted large numbers of c. imicola, which were seen near the treated net within a few minutes of the start of the experiment. initial collections in the traps were approximately 3 times as large as those in control traps with untre ...199910071502
stabling and the protection of horses from culicoides bolitinos (diptera: ceratopogonidae), a recently identified vector of african horse sickness.the stabling of horses at night reportedly offers protection from african horse sickness and the most significant vector of the disease, culicoides imicola kieffer, has been shown to be exophilic. in certain high-lying regions of south africa, however, c. bolitinos meiswinkel, may be the major vector of the disease but its entry behaviour into stables is unknown. accordingly, in the eastern free state province of south africa, light trap catches of c. bolitinos inside stables and outside, were c ...200011107252
use of climatic data and satellite imagery to model the abundance of culicoides imicola, the vector of african horse sickness virus, in morocco.african horse sickness (ahs) is a vector-borne, infectious disease of equids caused by african horse sickness virus (ahsv). the only proven field vector of the virus is the biting midge culicoides imicola. following a recent epizootic (1989-91) of ahs in morocco, light traps and automatic weather stations were operated for 2 years at twenty-two sites distributed over much of the country. the annually-averaged mean daily trap catch of c. imicola at these sites was negatively correlated with wind ...19989737597
prevalence of culicoides imicola and other species (diptera: ceratopogonidae) at eight sites in zimbabwe. 200111513259
using climate data to map the potential distribution of culicoides imicola (diptera: ceratopogonidae) in europe.culicoides imicola, a vector of bluetongue virus and african horse sickness virus, is principally afro-asian in distribution, but has recently been found in parts of europe. a logistic regression model based on climate data (temperature, saturation deficit, rainfall and altitude) and the published distribution of c. imicola in iberia was developed and then applied to other countries in europe, to identify locations where c. imicola could become established. the model identified three temperature ...200111732415
prediction of areas around the mediterranean at risk of bluetongue by modelling the distribution of its vector using satellite imaging.bluetongue is an infectious disease of ruminants caused by a virus transmitted by biting midges, one species of which, culicoides imicola, is the major vector in the old world. following an epizootic of african horse sickness,a related disease, in iberia and morocco between 1987 and 1991, c imicola was trapped for two years at 44 sites in the affected region and models were developed for predicting the abundance of c imicola at these sites. discriminant analysis was applied to identify the best ...200111764324
simulation studies of vaccination strategies in african horse sickness.a simulation model including two hosts (horses and donkeys) and one vector (culicoides imicola) for african horse sickness in spain is extended to consider vaccination strategies. if hosts were protected prior to virus introduction, elimination of simulated epidemics was related nonlinearly to the fraction protected. protecting donkeys as well as horses increased the effectiveness of vaccination. prevention of 50% of epidemics required 75% coverage of horses and donkeys or 90% coverage of horses ...19979160519
seasonal abundance of four culicoides spp. (diptera: ceratopogonidae) at al-ahsa oasis, eastern province, saudi arabia.this report constitutes the first study of culicoides spp. and their seasonal abundance at al-ahsa, the largest oasis in the eastern province of saudi arabia. new jersey light traps were used to collect the midges at mastock farm and al-mansura village. the mean monthly abundance was determined from october 1993 to october 1994. the mean monthly number per trap reached its minimum value during january 1994, increasing gradually from february to reach its maximum value during september 1994. duri ...200212233996
spatial and seasonal distribution of culicoides imicola in iberia in relation to the transmission of african horse sickness virus.collections of biting midges were made over 24 months from sixty sites spread across iberia. information on the distribution of the vector of african horse sickness virus, culicoides imicola, from these 3119 samples showed that this species was annually present across south-western spain as far as 3 degrees 53'w and throughout most of portugal, up to 41 degrees 5'n. c. imicola was found in all areas where african horse sickness epizootics had occurred in 1987-90 and also in areas outside the epi ...19979061677
susceptibility of culicoides imicola to cyhalothrin. 19958541601
the transmission and geographical spread of african horse sickness and bluetongue viruses.african horse sickness virus (ahsv) and bluetongue virus (btv) are dsrna viruses within the genus orbivirus. both are able to cause non-contagious, infectious arthropod-borne diseases in their respective vertebrate hosts. ahsv infects equines and occasionally dogs, whereas btv replicates in ruminants. the disease caused by ahsv is usually at its most severe in horses, whereas certain breeds of sheep are particularly sensitive to btv infection. ahsv is endemic in sub-saharan africa but periodical ...19957741589
preferred landing sites of culicoides species (diptera: ceratopogonidae) on a horse in israel and its relevance to summer seasonal recurrent dermatitis (sweet itch).six hundred and twenty culicoides of five species were collected from a bait horse at kannot, israel, between april and september 1986. seventy-two per cent of the midges were collected from the belly and 27 per cent from the dorsal aspect of the body, ie, the sweet itch summer seasonal recurrent dermatitis (ssrd) zone. midges were active mainly from half an hour prior to half an hour after sunset. only culicoides puncticollis, c imicola and c schultzei group were collected in considerable numbe ...19883215168
the use of a membrane feeding technique to determine the infection rate of culicoides imicola (diptera, ceratopogonidae) for 2 bluetongue virus serotypes in south africa.culicoides spp. in the lowveld of the northern transvaal, republic of south africa, were fed bluetongue virus serotypes 3 and 6 and african horsesickness virus serotype 1 through latex and chicken skin membranes. after an incubation period of 10 days at 25-27 degrees c, the infection rate of c. imicola for bluetongue virus serotypes 3 and 6 was established at 31% and 24% respectively. no african horsesickness virus could be recovered. the membrane feeding technique and handling procedures proved ...19911646980
prediction of bluetongue vector distribution in europe and north africa using satellite imagery.bluetongue is an infectious, non-contagious arboviral disease thought to infect all known ruminant species. since 1998, an unprecedented epizootic of the disease has occurred in the mediterranean region, resulting in the deaths of over 800,000 sheep to date. bluetongue virus (btv) is transmitted by biting midges of which one species, culicoides imicola, is the major vector in the old world. c. imicola was trapped for 2 years at 87 sites across portugal and models were developed for predicting th ...200314637035
studies on culicoides species of nigeria. vii. the biology of some nigerian culicoides species.during field investigations into the biology of culicoides species of nigeria, 8,795 newly emerged culicoides comprising of 20 species were caught with emergence traps at the teaching and research farm of the university of ibadan. culicoides imicola kieffer was the most predominant followed by c. quinquelineatus goetghebuer and c. endelini endeline. two groups of culicoides species were recognized. these were those breeding only during the rains with emergence peaks in june and august and those ...1977871067
geographical and seasonal distribution of the bluetongue virus vector, culicoides imicola, in central italy.following the first incursion of bluetongue virus (btv) into italy, the geographical and seasonal distribution of the biting midge culicoides imicola kieffer (diptera: ceratopogonidae), the main vector of btv and african horse sickness virus, was investigated in two regions of central italy (lazio and tuscany). surveillance of culicoides was carried out between july 2001 and december 2002 using light traps: 1917 collections were made in 381 trap sites, well distributed across both regions. durin ...200314651652
african horse sickness epidemiology: vector competence of south african culicoides species for virus serotypes 3, 5 and 8.the oral susceptibilities of 17 culicoides species to infection with african horse sickness virus (ahsv) serotypes 3, 5 and 8 were determined by feeding field-collected midges on ahsv infected horse blood. the mean titres of virus in the bloodmeals for the three serotypes of ahsv were between 5.7 and 6.5 log10 tcid50/ml. virus was detected, after 10 days incubation at 23.5 degrees c, in the culicoides imicola kieffer (diptera: ceratopogonidae) that had fed on blood containing ahsv 5 (8.5%) and 8 ...200011016430
a preliminary attempt to use climate data and satellite imagery to model the abundance and distribution of culicoides imicola (diptera: ceratopogonidae) in southern africa.abundances of culicoides imicola, the insect vector of several livestock viruses, including bluetongue and african horse sickness, were recently published for 34 sites in southern africa, together with associated climate data. here, these data are analysed statistically in combination with certain satellite-derived variables, with the aim of developing predictive models of c. imicola abundance. satellite-derived variables were the land surface temperature (lst, a measure of temperature at the ea ...199910855827
seasonal distribution and relationship to temperature and precipitation of the most abundant species of culicoides in five provinces of andalusia, spain.a total of 177,344 culicoides specimens were collected from 3,109 light trap collections made weekly from august 1990 to october 1991 at 62 sites in the provinces of cádiz, córdoba, huelva, seville, and málaga, spain. reported for the 1st time are culicoides agathensis, culicoides bahrainensis, culicoides marcleti, and culicoides odiatus in the iberian peninsula, and culicoides scoticus in andalusia, spain. as a group, culicoides were active throughout the year. the 3 most common species were cu ...199910480132
[risk assessment of bluetongue disease incursion into germany using geographic information system (gis)].using a geographic information system (gis), by analysis of the relationship between the spatial distribution of cattle density and the risk factors temperature, altitude and rainfall, we defined geographical habitats enabling optimal development and competence of culicoides spp. to transmit bluetongue-virus (btv): risk zones (low, high, highest risk) were identified mainly in baden-württemberg, hessen and rheinland-pfalz if persistently infected ruminants are imported into these zones in summer ...200415188681
spatial distribution of bluetongue virus and its culicoides vectors in sicily.during the recent mediterranean epizootic of bluetongue, an extensive programme of serological and vector (culicoides biting midges (diptera: ceratopogonidae)) surveillance was carried out across sicily. this paper presents the analysis of 911 light trap catches collected at the times of peak culicoides abundance (summer to autumn 2000-2002) in 269 sites, in order to produce detailed maps of the spatial distribution of the main european vector, culicoides imicola kieffer and that of potential no ...200415189232
modelling the distributions of culicoides bluetongue virus vectors in sicily in relation to satellite-derived climate variables.surveillance data from 268 sites in sicily are used to develop climatic models for prediction of the distribution of the main european bluetongue virus (btv) vector culicoides imicola kieffer (diptera: ceratopogonidae) and of potential novel vectors, culicoides pulicaris linnaeus, culicoides obsoletus group meigen and culicoides newsteadi austen. the models containing the 'best' climatic predictors of distribution for each species, were selected from combinations of 40 temporally fourier-process ...200415189233
duration of repellency of various synthetic and plant-derived preparations for culicoides imicola, the vector of african horse sickness virus.objectives of the study were threefold: to find a safer and longer lasting repellent of the biting midge culicoides imicola than di-ethyl toluamide (deet), to examine whether the current recommendations in israel for application of repellents during an outbreak of c. imicola-borne pathogens are justified; and to examine whether plant-derived preparations that have no known detrimental side effects are potential replacements of synthetic repellents. of the seven repellents tested, those inferior ...19989785505
modelling the distribution and abundance of culicoides imicola in morocco and iberia using climatic data and satellite imagery.relative abundances of culicoides imicola at 22 sites in morocco were compared with climatic variables, altitude and the ndvi (normalised difference vegetation index, a satellite derived measure of photosynthetic activity) of the same sites. abundances were negatively correlated with wind speed and positively correlated with the average and minimum ndvi (ndvimin). there were no significant correlations with air or soil temperatures, relative humidity, saturation deficit, rainfall, altitude or me ...19989785503
climate change and the recent emergence of bluetongue in europe.bluetongue, a devastating disease of ruminants, has historically made only brief, sporadic incursions into the fringes of europe. however, since 1998, six strains of bluetongue virus have spread across 12 countries and 800 km further north in europe than has previously been reported. we suggest that this spread has been driven by recent changes in european climate that have allowed increased virus persistence during winter, the northward expansion of culicoides imicola, the main bluetongue virus ...200515685226
identification of culicoides obsoletus (diptera: ceratopogonidae) as a vector of bluetongue virus in central italy.in 2001 and 2002, 235 outbreaks of bluetongue were observed in the lazio and tuscany regions of central italy. during entomological surveillance culicoides imicola, the main vector of bluetongue virus in the mediterranean region, was detected in only 14 of 28 municipalities affected by outbreaks; culicoides obsoletus was the most abundant species, contributing 83 per cent of individuals in catches, whereas c. imicola contributed only 2 per cent. in affected municipalities the maximum catch of c. ...200515786918
expansion of culicoides imicola, the main bluetongue virus vector in europe, into catalonia, spain. 200515816196
active circulation of bluetongue vaccine virus serotype-2 among unvaccinated cattle in central italy.several seroconversions occurring in 2002 among sentinel cattle during the bluetongue-vaccination campaign in lazio and tuscany (central italy) led to the suspicion of vaccine-virus circulation. therefore in 2003, 17 seroconverting sentinel herds were investigated for the characteristics of the virus involved. from these farms, 91 unvaccinated animals and 57 culicoides pools were tested for the presence of the bluetongue vaccine virus (serotype-2) or other strains. the presence of vaccine virus ...200515820110
studies of the mortality rate of culicoides imicola in morocco.daily mortality rates of female culicoides imicola were found for eight sites in morocco in 1994 and for six sites in 1995. the mortality rates were found by operating pirbright-type light traps for a number of consecutive nights in late summer or autumn and finding the parous rate assuming a feeding interval of 3 to 5 days. the mortality rates were calculated according to established methods. in morocco the daily mortality rates were found to vary from about 5% per day (arbaoua, 1994, 1995 and ...19989785502
the culicoides vectors of african horse sickness virus in morocco: distribution and epidemiological implications.african horse sickness (ahs) is a vector-borne, infectious disease of equids caused by african horse sickness virus. the only proven field vector of the virus is the biting midge culicoides imicola, although c. obsoletus and c. pulicaris are suspected vectors. in 1994-5 a total of 3887 light trap samples were collected from 22 sites distributed over most of morocco. culicoides imicola was found to be very widely distributed with the greatest catches in the low-lying north-western areas (between ...19989785501
an alternative method of blood-feeding culicoides imicola and other haematophagous culicoides species for vector competence studies.the use of cotton wool pads saturated with blood/virus mixture for oral infection attempts was compared to membrane feeding for the assessment of vector competence in c. imicola kieffer and c. bolitinos meiswinkel (diptera, ceratopogonidae). although lower infection rates were obtained using pad feeding, it was possible to clearly distinguish the levels of competence between species as well as differences in virus infection rates for various serotypes of bluetongue virus. reduced infection rates ...200515964690
simulation studies of african horse sickness in spain.factors affecting epidemics of african horse sickness in spain were studied using a mathematical model. the model examined the likelihood of an epidemic after the introduction of the virus, and the effectiveness of vaccination strategies. two host species (horses and donkeys) and one vector species (the biting midge culicoides imicola) were included. a stratified random sampling method (latin hypercube sampling) was used for sensitivity analysis of the likelihood of an epidemic. systematic varia ...19989785500
spatial distribution of culicoides imicola, the main vector of bluetongue virus, in spain. 200616443839
oral susceptibility to bluetongue virus of culicoides (diptera: ceratopogonidae) from the united kingdom.oral susceptibility to infection with bluetongue virus (family resviridae, genus orbivirus, btv) serotype 9 was characterized in three palaearctic species of culicoides (diptera: ceratopogonidae). variation in susceptibility to infection by using a recently described feeding technique was shown to occur between populations of culicoides obsoletus meigen complex midges from different geographic regions of the united kingdom with virus infection rates varying from 0.4 to 7.4% of those tested. susc ...200616506450
the relationship between climate and the distribution of culicoides imicola in iberia.the biting midge culicoides imicola was captured at 17 of 27 farms in spain and portugal during a survey of its distribution following outbreaks of african horse sickness in iberia that occurred between 1987 and 1990. farms were sampled approximately twice weekly from october 1992 to february 1995. farms were widely spaced apart (maximum 850 km) and had considerable variation in climate. across sites, summer temperatures ranged from 18.3 degrees c-27.2 degrees c; in winter the range was 4.4 degr ...19989785499
the seasonal and geographical distribution of culicoides imicola, c. pulicaris group and c. obsoletus group biting midges in central and southern spain.pirbright-type light traps were used to collect culicoides biting midges (diptera: ceratopogonidae) at fifteen sites in twelve provinces of central spain and andalusia. a total of 293,625 culicoides were collected in 1,387 samples over a two year period. these comprised approximately 9.2% culicoides imicola, 11.4% c. pulicaris group, 1.6% c. obsoletus group and 12.2% c. circumscriptus. culicoides imicola was present at ten of the fifteen sites; the five sites from which it was absent were the mo ...19989785498
the 1996 outbreak of african horse sickness in south africa--the entomological perspective.during the 1996 summer season (january-april) in south africa an estimated 500 horses died of african horse sickness (ahs); 80% of deaths were due to ahs virus serotypes 2 and 4. nearly all cases occurred in the northern, north-eastern and central parts of south africa. this study reports the first attempt to verify the involvement of the biting midge culicoides imicola in a field outbreak of ahs in southern africa. in light-trap collections made at 47 sites over 12 weeks, c. imicola comprised 9 ...19989785497
seasonal and geographical distribution of culicoides imicola kieffer (diptera: ceratopogonidae) in southwestern spain.culicoides imicola kieffer adults were collected in light traps weekly between august 1990 and october 1991. the species was collected at all 62 sites located in 5 provinces of the autonomous region of andalucía (spain). culicoides imicola represented 31.7% of the total collection of culicoides. the highest numbers of c. imicola were collected from september through november 1990 and september and october 1991. the lowest numbers were collected from december 1990 through april 1991. the presence ...19979383762
distribution and abundance of bluetongue vectors in sardinia: comparison of field data with prediction maps.following the spread of bluetongue virus (btv) in many mediterranean countries during the last 5 years, presence of the main btv vector, culicoides imicola kieffer (diptera: ceratopogonidae), was recorded in the region, including the island of sardinia where the first bt epidemic originally started in the year 2000. several models were also designed based on climate variables and satellite imaging in order to predict the presence and abundance of btv vectors across europe. a 3 years entomologica ...200616930274
comparison of black and white light for collecting culicoides imicola and other livestock-associated culicoides species in south africa.comparison of the effectiveness of 8w fluorescent black and white light sources, in two 4x4 latin squares (16 replicates) designs under south african conditions, showed black light to be up to three time more effective in collecting culicoides imicola kieffer (diptera, ceratopogonidae) and other south african culicoides species. four culicoides species, which were collected in low numbers with black light, were not collected in traps equipped with the white light source. no significant differenc ...200616934933
vector-borne diseases and the basic reproduction number: a case study of african horse sickness.the basic reproduction number, r0, can be used to determine factors important in the ability of a disease to invade or persist. we show how this number can be derived or estimated for vector-borne diseases with different complicating factors. african horse sickness is a viral disease transmitted mainly by the midge culicoides imicola. we use this as an example of such a vector-transmitted disease where latent periods, seasonality in vector populations, and multiple host types may be important. t ...19968834738
establishment of an early warning system against bluetongue virus in switzerland.bluetongue (bt) is a vector-borne animal disease of economical importance due to the international trade restrictions likely to be put into place in a country once the infection is discovered. the presence of bt and its vectors in countries adjacent to switzerland stresses the need of implementing a surveillance system and to raise disease awareness among potential stakeholders. a national survey in switzerland 2003 indicated freedom of bluetongue virus (btv), although a single individual of the ...200617209508
african horse sickness: transmission and epidemiology.african horse sickness (ahs) virus causes a non-contagious, infectious, arthropod-borne disease of equines and occasionally of dogs. the virus is widely distributed across sub-saharan african where it is transmitted between susceptible vertebrate hosts by the vectors. these are usually considered to be species of culicoides biting midges but mosquitoes and/or ticks may also be involved to a greater or lesser extent. periodically the virus makes excursions beyond its sub-saharan enzootic zones bu ...19938102076
assessing the risk of bluetongue to uk livestock: uncertainty and sensitivity analyses of a temperature-dependent model for the basic reproduction number.since 1998 bluetongue virus (btv), which causes bluetongue, a non-contagious, insect-borne infectious disease of ruminants, has expanded northwards in europe in an unprecedented series of incursions, suggesting that there is a risk to the large and valuable british livestock industry. the basic reproduction number, r(0), provides a powerful tool with which to assess the level of risk posed by a disease. in this paper, we compute r(0) for btv in a population comprising two host species, cattle an ...200817638649
description of breeding sites of culicoides species (diptera: ceratopogonidae) in turkey.the aim of this study was to describe the breeding sites of culicoides species in konya province, turkey. the samples taken from 11 different habitats in konya province were examined for culicoides species. the collected adult culicoides specimens were reared in plastic buckets in our laboratory. among 2,798 specimens reared, 18 species were identified. culicoides circumscriptus kieffer, 1918 was the most abundant species reared in the samples taken from mud rich in organic matters near the wate ...200717645192
molecular differentiation of the old world culicoides imicola species complex (diptera, ceratopogonidae), inferred using random amplified polymorphic dna markers.samples of seven of the 10 morphological species of midges of the culicoides imicola complex were considered. the importance of this species complex is connected to its vectorial capacity for african horse sickness virus (ahsv) and bluetongue virus (btv). consequently, the risk of transmission may vary dramatically, depending upon the particular cryptic species present in a given area. the species complex is confined to the old world and our samples were collected in southern africa, madagascar ...200111472544
comparative descriptions of the pupae of five species of the culicoides imicola complex (diptera, ceratopogonidae) from south africa.the viruses causing the economically important livestock diseases of african horse sickness (ahs) and bluetongue (bt) are transmitted by biting midges of the genus culicoides (diptera, ceratopogonidae). in the old world the most important vectors of these diseases are culicoides imicola kieffer, 1913, culicoides brevitarsis kieffer, 1917 and culicoides bolitinos meiswinkel, 1989. all three of these vectors belong to the imicola complex of the subgenus avaritia fox, 1955. this species complex now ...200717883197
akabane virus in israel: a new virus lineage.this report describes the first molecular characterization of akabane virus (akav) in israel. the virus was recognized by real-time rt-pcr in extracts from culicoides imicola insects trapped at the volcani center located in the center of israel. this is also the first report on the use of real-time rt-pcr to identify the virus. the quantitative capability of this technique was applied, and it was calculated that the insect extract contains 1.5 x 10(5) copies of the genome segment s. following am ...200415177897
heterogeneity of its1 sequences in the biting midge culicoides impunctatus (goetghebuer) suggests a population in argyll, scotland, may be genetically distinct.ribosomal dna (rdna) internal transcribed spacer 1 (its1) is a useful genomic region for understanding evolutionary and genetic relationships. in the current study, variation in its1 from eight culicoides species was analysed by pcr, dna restriction analysis, cloning, and sequencing. its1 variants were essentially homogenized within a species, as sequences were identical or closely related. however, culicoides impunctatus its1 sequences derived from one (argyll) of five populations contained con ...200415190372
phylogenetic analysis of the mitochondrial cytochrome oxidase subunit i gene of five species of the culicoides imicola species complex.the phylogenetic status of members of the culicoides imicola kieffer (diptera: ceratopogonidae) species complex of haematophagous midges is unknown, and simple means to identify the members using all life stages are unavailable. in this study, the status of three confirmed (c. imicola s.s., c. bolitinos meiswinkel and c. loxodontis meiswinkel) and two provisional (c. tuttifrutti meiswinkel and c. kwagga meiswinkel) members of the complex from south africa was assessed using phylogenetic analysis ...200212109707
bluetongue epidemiology in the european union.bluetongue (bt) is a reportable disease of considerable socioeconomic concern and of major importance in the international trade of animals and animal products. before 1998, bt was considered an exotic disease in europe. from 1998 through 2005, at least 6 bt virus strains belonging to 5 serotypes (btv-1, btv-2, btv-4, btv-9, and btv-16) were continuously present in the mediterranean basin. since august 2006, btv-8 has caused a severe epizootic of bt in northern europe. the widespread recrudescen ...200818394269
culicoides biting midges at the national zoological gardens of south africa.culicoides biting midges (diptera: ceratopogonidae) are responsible for the transmission of a large number of pathogens to livestock and wild animals. in this study the presence of the genus, using light traps based at four different sites within the national zoological gardens of south africa, was investigated during 2002-2004. in total, 37 species were recorded, including large numbers of culicoides imicola kieffer, 1913, which is responsible for the transmission of economically important arbo ...200718453243
modelling the distributions and spatial coincidence of bluetongue vectors culicoides imicola and the culicoides obsoletus group throughout the iberian peninsula.data obtained by a spanish national surveillance programme in 2005 were used to develop climatic models for predictions of the distribution of the bluetongue virus (btv) vectors culicoides imicola kieffer (diptera: ceratopogonidae) and the culicoides obsoletus group meigen throughout the iberian peninsula. models were generated using logistic regression to predict the probability of species occurrence at an 8-km spatial resolution. predictor variables included the annual mean values and seasonal ...200818498611
the distribution of culicoides imicola in italy: application and evaluation of current mediterranean models based on climate.in august 2000 bluetongue (bt) disease appeared amongst sheep on the island of sardinia spreading later to sicily and to mainland italy. the majority of areas affected by bt were surveyed for culicoides imicola, the only proven vector of the disease known to occur in the mediterranean region. the data from 1456 light-trap collections, made in months with a mean temperature of 12.5 degrees c, were used to test the accuracy of current models predicting the prevalence and abundance of c. imicola ac ...200312667191
first record of culicoides imicola, the main vector of bluetongue virus in europe, in the basque country (northern spain). 200818567930
bluetongue in europe and the mediterranean basin: history of occurrence prior to 2006.bluetongue virus (btv) exists around the world in a broad band covering much of the americas, africa, southern asia and northern australia. historically, it also occasionally occurred in the southern fringes of europe. it is considered to be one of the most important diseases of domestic livestock. recently btv has extended its range northwards into areas of europe never before affected and has persisted in many of these locations causing the greatest epizootic of bluetongue (bt), the disease ca ...200818619694
occurrence of culicoides spp. (diptera: ceratopogonidae) in tunisia, with emphasis on the bluetongue vector culicoides imicola.following the bluetongue (bt) outbreaks in tunisia from 1999 to 2002, btv (bluetongue virus) serotype 2 was isolated; however, no entomological investigation was performed. in the study presented here, we assessed the culicoides species populations (particularly c. imicola) in proximity to the bt outbreaks locations, both as a retrospective analysis and to update the list of culicoides species present in tunisia. the insects were caught using light traps and the species identification was perfor ...200818642513
the effect of climate on the presence of culicoides imicola in italy.a model was developed to classify the italian territories in relation to their suitability to harbour populations of culicoides imicola and, as a consequence, also able to sustain a bluetongue (bt) epidemic. italy was subdivided into 3507 10 x 10 km cells. in 546 cells at least one collection was made. the cell was considered the unit for all subsequent analyses. culicoides were collected using onderstepoort-type blacklight traps. some traps were operated weekly at chosen sites; the remainder we ...200312667192
endophily in culicoides associated with btv-infected cattle in the province of limburg, south-eastern netherlands, 2006.culicoides were captured at a btv-infected dairy near gulpen in the province of limburg (south-east netherlands) between 14 september and 4 october 2006. onderstepoort-type blacklight traps were used to sample culicoides both inside and outside a partially open shed housing 11 cattle. a total of 28 light trap collections were made at the shed and yielded: 9371 culicoides representing 11 species; >90% comprised five potential vectors of btv and in order of abundance were culicoides obsoletus and ...200818672304
simulation studies of african horse sickness and culicoides imicola (diptera:ceratopogonidae).a simulation model of african horse sickness in spain was developed to investigate what factors affect the likelihood of an epidemic after the introduction of the virus. the model included 2 host species (horses and donkeys) and 1 vector species (culicoides imicola kieffer). latin hypercube sampling was used for sensitivity analysis of the model, to include uncertainty in parameter estimates. in general, if an epidemic occurred most hosts were infected. the peak prevalence in midges was low, and ...19968667377
estimating the temporal and spatial risk of bluetongue related to the incursion of infected vectors into switzerland.the design of veterinary and public health surveillance systems has been improved by the ability to combine geographical information systems (gis), mathematical models and up to date epidemiological knowledge. in switzerland, an early warning system was developed for detecting the incursion of the bluetongue disease virus (bt) and to monitor the frequency of its vectors. based on data generated by this surveillance system, gis and transmission models were used in order to determine suitable seas ...200818922155
bluetongue: vector surveillance in austria in 2007.since the first outbreaks of bluetongue disease (btd) were reported from the netherlands, germany, and belgium in autumn of 2006, the disease is a main topic in central europe. the infectious disease, which originated in south africa and from which austria has been spared up to now, affects particularly sheep, cattle, also goats and wild ruminants - but never humans. transmitters of the bluetongue virus (btv, family reoviridae, genus orbivirus), which occurs in several 24 serotypes, are biting m ...200819066770
presence in the balearic islands (spain) of the midges culicoides imicola and culicoides obsoletus group.an outbreak of the livestock viral disease bluetongue (bt) was detected during september and october 2000 in the balearic islands, spain. due to the lack of information about the species of culicoides (diptera: ceratopogonidae) reported in the affected area, six farms in majorca, four in minorca and one in ibiza were selected to carry out surveillance of culicoides adults using light traps. here, for the first time, we report the presence in the balearic islands of culicoides imicola keiffer, th ...200312680925
newly emerged nulliparous culicoides imicola kieffer (diptera: ceratopogonidae) with pigmented abdomen.the method of segregating nulliparous and parous females of culicoides spp. based on the presence of burgundy-red pigment inside the abdominal wall of parous culicoides midges, is used worldwide. out of 320 females of culicoides imicola trapped by emergence traps, set over an artificial breeding site for 10 and 24 days, 73 (22.8%) showed a red-pigmentation despite the fact that they were nulliparous. this finding indicated that 23% of the "parous" females that are examined for the presence of ar ...200919111992
spatial distribution of culicoides species in portugal in relation to the transmission of african horse sickness and bluetongue viruses.surveillance of culicoides (diptera: ceratopogonidae) biting midge vectors was carried out at 87 sites within a 50 x 50 km grid distributed across portugal, using light trap collections at the time of peak midge abundance. culicoides imicola (kieffer) made up 66% of the 55 937 culicoides in these summer collections. it was highly abundant in the central eastern portion of portugal, between 37 degrees 5' n and 41 degrees 5' n, and in a band across to the lisbon peninsula (at around 38 degrees 5' ...200312823834
pcr identification of culicoides dewulfi midges (diptera: ceratopogonidae), potential vectors of bluetongue in germany.due to the severe outbreaks of bluetongue disease (btd) in the years 2006/2007 in germany in the absence of the main african vector culicoides imicola, a rapid and easy applicable method for identification of autochthonous culicoides spp. had to be developed. morphological identification is time-consuming, rendering impossible the identification of large numbers of midges in a short period of time. a polymerase chain reaction (pcr)-based procedure in connection with a species-specific primer gre ...200919308451
isolations of african horse sickness virus from vector insects made during the 1988 epizootic in spain.this paper describes the first isolations of african horse sickness virus (ahsv) from insects in spain. seven isolations of ahsv serotype 4 were made; four from culicoides imicola a known vector of the virus elsewhere, two from mixed pools of culicoides species not including c. imicola and one from blood engorged mosquitoes. three further isolations of ahsv serotype 4 were also made from horses kept adjacent to the insect collecting sites. this work presents the first definitive identification o ...19902209746
phylogenetic status and matrilineal structure of the biting midge, culicoides imicola, in portugal, rhodes and israel.the biting midge culicoides imicola kieffer (diptera: ceratopogonidae) is the most important old world vector of african horse sickness (ahs) and bluetongue (bt). recent increases of bt incidence in the mediterranean basin are attributed to its increased abundance and distribution. the phylogenetic status and genetic structure of c. imicola in this region are unknown, despite the importance of these aspects for bt epidemiology in the north american bt vector. in this study, analyses of partial m ...200314651651
detection of israel turkey meningo-encephalitis virus from mosquito (diptera: culicidae) and culicoides (diptera: ceratopogonidae) species and its survival in culex pipiens and phlebotomus papatasi (diptera: phlebotomidae).israel turkey meningo-encephalitis (itme) virus was detected in pools of ochlerotatus caspius pallas and culicoides imicola kieffer trapped at a turkey run at nir david during an outbreak in august 1995. experimental membrane feeding on a blood itme suspension showed that culex pipiens l. became harbored virus for at least 14 d. when phlebotomus papatasi scopoli were fed on an infected turkey, they became infected and harbored the virus for at least 7 d. because phlebotomines are trapped frequen ...200314680120
an investigation on the culicoides species composition at seven sites in southern switzerland.in the past decade, there have been regular outbreaks of bluetongue (bt) in many parts of europe. owing to the presence of bt disease and its vectors in countries adjacent to switzerland, an initial entomological survey was conducted in 2003, which established the presence of several midges of the genus culicoides (diptera: ceratopogonidae). subsequently, a sentinel herd monitoring system was established with the primary entomological aim being the determination and further study of culicoides p ...200919493190
entry of bluetongue vector culicoides imicola into livestock premises in spain.culicoides imicola kieffer is considered to be the main vector of bluetongue disease (bt) and african horse sickness (ahs) in the mediterranean basin. it has been assumed that this midge species is exophilic and, consequently, that stabling of livestock should provide effective protection against these diseases. this study presents the results of sampling surveys for c. imicola carried out both inside and outside stables on three farms in mainland spain. the number of c. imicola captured varied ...200919531066
the epidemiology and diagnosis of bluetongue with particular reference to corsica.bluetongue (bt) and/or bt viruses (btv) have been identified in the mediterranean basin and the balkans each year from 1998 to 2002 and in particular btv serotype 2 in the french island of corsica (2000 and 2001). in response to these virus incursions, the french veterinary authorities carried out epidemiological studies that included virological, serological and entomological analysis, and two vaccination campaigns performed in the winter of 2000/2001 and the winter and spring of 2001 and 2002. ...200415120946
environmental and biological factors influencing culex pipiens quinquefasciatus say (diptera: culicidae) vector competence for saint louis encephalitis virus.complex interactions between environmental and biological factors influence the susceptibility of culex pipiens quinquefasciatus to st. louis encephalitis virus and could affect the epidemiology of virus transmission. similar interactions could have epidemiologic implications for other vector-virus systems. we conducted an experiment to examine four such factors in combination: mosquito age, extrinsic incubation temperature (eit), virus dose, and colony. the proportion of mosquitoes with body in ...200919635881
molecular identification of western european species of obsoletus complex (diptera: ceratopogonidae) by an internal transcribed spacer-1 rdna multiplex polymerase chain reaction assay.in southern europe, orbiviral diseases such as bluetongue (bt) have been assumed to have been largely transmitted by the classical afro-asian vector culicoides imicola kieffer (diptera: ceratopogonidae). recent outbreaks have occurred in regions where c. imicola is normally absent, supporting the theory that other species belonging to the obsoletus or pulicaris complexes may play a role in bt virus transmission. investigations of the ecology of the species within the former group are hampered by ...200718047201
molecular detection of culicoides spp. and culicoides imicola, the principal vector of bluetongue (bt) and african horse sickness (ahs) in africa and europe.bluetongue (bt) and african horse sickness (ahs) are infectious arthropod-borne viral diseases affecting ruminants and horses, respectively. culicoides imicola kieffer, 1913, a biting midge, is the principal vector of these livestock diseases in africa and europe. recently bluetongue disease has re-emerged in the mediterranean basin and has had a devastating effect on the sheep industry in italy and on the islands of sicily, sardinia, corsica and the balearics, but fortunately, has not penetrate ...200415210081
predicting the risk of bluetongue through time: climate models of temporal patterns of outbreaks in israel.determining the temporal relationship between climate and epidemics of culicoides-borne viral disease may allow control and surveillance measures to be implemented earlier and more efficiently. in israel, outbreaks of bluetongue (bt) have occurred almost annually since at least 1950, with severe episodes occurring periodically. in this paper, the authors model a twenty-year time-series of bt outbreaks in relation to climate. satellite-derived correlates of low temperatures and high moisture leve ...200415861871
a comparison of the susceptibility of culicoides imicola and c. bolitinos to oral infection with eight serotypes of epizootic haemorrhagic disease virus.the mechanisms involved in introduction, maintenance and perpetuation of epizootic haemorrhagic disease virus (ehdv) in south africa are not fully understood. this paper reports on the susceptibility of south african livestock associated culicoides (diptera: ceratopogonidae) species to oral infection with eight ehdv serotypes. virus was recovered from eight of 17 field-collected culicoides species 10 days after oral feeding on blood/virus mixtures. six ehdv serotypes were recovered from c. (avar ...200515958026
the spread of bluetongue virus serotype 8 in great britain and its control by vaccination.bluetongue (bt) is a viral disease of ruminants transmitted by culicoides biting midges and has the ability to spread rapidly over large distances. in the summer of 2006, btv serotype 8 (btv-8) emerged for the first time in northern europe, resulting in over 2000 infected farms by the end of the year. the virus subsequently overwintered and has since spread across much of europe, causing tens of thousands of livestock deaths. in august 2007, btv-8 reached great britain (gb), threatening the larg ...201020179768
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