TitleAbstractYear(sorted descending)
tick infestations on zebu cattle in western kenya: individual host variation.monthly collections were made of all ticks from 25 mature east african zebu cattle and 5 yearlings for 13 mo on rusinga island, lake victoria, kenya, from september 1986 to september 1987. the most common species were rhipicephalus appendiculatus neumann and amblyomma variegatum f.; boophilus decoloratus koch and rhipicephalus evertsi evertsi neumann also were present in fewer numbers. cattle were ranked according to their degree of resistance to each of the four species and to each stage in the ...19912033602
increased population densities of amblyomma americanum (acari: ixodidae) on long island, new york.lone star ticks, amblyomma americanum comprised a significantly greater proportion of total ticks flagged on eastern long island and fire island, new york, in 1986 and 1990 than in samples reported by other authors from the 1940s (when a. americanum was not collected by flagging or from hosts) and the 1970s. therefore, population densities of a. americanum apparently have increased in recent years on southeastern long island, where this species now is distributed widely.19912040963
further investigations on the action of ecdysteroids on the salivary glands of the female tick amblyomma americanum.two phytecdysteroids (abutasterone, makisterone a) and five synthetic ecdysteroid analogues, all at 1 microgram/ml, were tested on salivary glands from the female tick, amblyomma americanum l. (acari:ixodidae), held in organ culture for four days. all of these substances caused a significant reduction in fluid secretory competence of salivary glands in vitro. this constitutes further evidence that the structural requirements for causing salivary-gland degeneration in ticks are similar to those g ...19912044433
seasonal abundance of ticks associated with indigenous goats on a northern transvaal farm.the 3 most abundant tick species on indigenous goats on a northern transvaal farm were found to be rhipicephalus evertsi evertsi, rhipicephalus appendiculatus and amblyomma hebraeum. three other tick species were present in small numbers. the economical and ecological importance of the ticks found on the goats, mainly in rural areas where chemical control of ticks is practically non-existant, is discussed. the high number of goats in the study area and the shift towards alternative methods of ti ...19912051439
drag-sampling of free-living ixodid ticks in the kruger national ticks were collected by means of drag-sampling in 32 of the 35 landscape zones of the kruger national park during a period of 1 calendar month. of the 18,199 specimens collected, 99.53% were larvae, 0.05% nymphs and 0.42% adults. fourteen species were collected. amblyomma hebraeum followed by boophilus decoloratus, predominated, both in distribution and abundance. large variations were encountered between drags. there was no correlation between the numbers of larvae collected and tim ...19912052317
hyperosmotic oral fluid secretion during active water vapour absorption and during desiccation-induced storage-excretion by the unfed female tick amblyomma americanum. 19912061709
isolation of borrelia burgdorferi from arthropods collected in texas.the texas department of health laboratory cultured arthropods from november 1988 through december 1989 in an attempt to isolate borrelia burgdorferi, the etiologic agent of lyme disease. spirochetes were isolated from eight of 1,093 pools of arthropods cultured. the spirochetal isolates were from several tick and one flea species, including amblyomma americanum, a. maculatum, ixodes scapularis, and ctenocephalides felis. these 8 isolates reacted specifically when treated with monoclonal antibodi ...19912063950
putative new expression of genes in ixodid tick salivary gland development during feeding.poly(a+) mrna-enriched fractions from salivary glands of partially fed amblyomma americanum female ticks were translated in vitro with a rabbit reticulocyte translation system. translated proteins were labeled with [35s]methionine, separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis, and identified by autoradiography. thirty major identifiable polypeptides with molecular weights ranging from 14 to 136 kda were synthesized from mrna isolated from salivary glands of ticks weighi ...19911710268
sites of attachment in amblyomma triguttatum triguttatum koch (acari: ixodidae) on natural hosts.the sites of attachment of amblyomma triguttatum truguttatum were studied from june to september 1981 on 146 feral pigs (sus scrofa) and from march to august 1982 and january 1983 on 68 grey kangaroos (macropus giganteus), naturally infested. two hundred fifty hour (81%) of 314 nymphs were detected on the ears of the pigs; neither adults nor larvae of a. t. triguttatum were found on s. scrofa. six hundred ninety four (97%) of 715 larvae; 283 (96%) of 295 nymphs and 11 (79%) of 14 adults of a. t. ...19902080832
cattle breed alters reproduction in amblyomma americanum (acari: ixodidae).female amblyomma americanum [l.] that feed on bos taurus cattle weigh significantly (p = 0.05) more (mean = 505.4 mg) than females that feed on b. indicus x b. taurus cattle (mean = 450.7 mg) but not females that feed on b. indicus cattle (mean = 489.7 mg). females that feed on b. taurus cattle lay more eggs (mean = 3492) and produce more larvae (mean = 3243) than females that feed on b. indicus cattle (mean = 3103 eggs; 2925 larvae) or b. indicus x b. taurus cattle (mean = 2961 eggs; 2759 larva ...19902081445
non-viraemic transmission of thogoto virus: vector efficiency of rhipicephalus appendiculatus and amblyomma variegatum.previous studies have demonstrated that thogoto virus is transmitted from infected to uninfected ticks when co-feeding on uninfected guinea-pigs, even though the guinea-pigs do not develop a detectable viraemia. furthermore, tick to tick transmission is potentiated by factors associated with the salivary glands of ticks (saliva activated transmission). the vector efficiency of 2 ixodid tick species, rhipicephalus appendiculatus and amblyomma variegatum, for thogoto virus was assessed using this ...19902096521
[spreading of the tick amblyomma variegatum in the west indies: how can this serious menace be explained and what should be done?].the author presents a brief history of the introduction and extension of the african tick amblyomma variegatum in the caribbean. the tick is particularly dangerous for the livestock industry because of its role as a vector of heartwater and its association with severe dermatophilosis. it is already distributed in the lesser antilles from puerto rico to barbados and st. vincent. the chronology of its sudden unexplained expansion since the 1960s corresponds well with the multiplication of the catt ...19902103050
the impact of pure infestations of rhipicephalus appendiculatus and amblyomma hebraeum on the productivity of cattle and implications for tick control strategies in africa.this paper reviews studies carried out by an fao project in zimbabwe, on the effects of the ticks rhipicephalus appendiculatus and amblyomma hebraeum on the productivity of cattle. larvae and nymphs of the two species had no detectable effect on liveweight gain (lwg). the losses in lwg caused by each adult female that completed feeding were approximately 4 g for r. appendiculatus and 10 g for a. hebraeum. losses in milk production caused by both species amounted to approximately 7 g for every fe ...19902126617
the impact of natural infestations of ticks in zambia on the productivity of cattle and implications for tick control strategies in central africa.studies were carried out in zambia using a farming systems approach to quantify the effects of tick control on traditionally managed sanga cattle. in the first trial to investigate the effect of tick control, significant improvements in liveweight gain (lwg) occurred only in periods of medium to high challenge with adult amblyomma variegatum. however, during the first 18 months of the study when animals were young, the acaricide used caused a suppression in weight gains. a supplementary experime ...19902126618
the effect of amblyomma variegatum on liveweight gain of cattle in zambia.the effect of the tick amblyomma variegatum fabricius on liveweight gain (lwg) on yearling cattle over 16 weeks was evaluated under quasi-natural conditions. early in the exposure period when animals may have been in a state of suppressed metabolism, the effect of tick feeding on lwg was negligible. overall, however, the difference in lwg between tick-free and tick-infested groups of cattle was 4.95 kg after 16 weeks. this difference between the groups was used to estimate a lower lwg of 48-63 g ...19902132999
[lymphatic cutaneous rickettsiosis caused by rickettsia conorii in uruguay].three autochthonous cases of cutaneous-ganglionar rickettsiosis transmitted by dogs ticks (amblyomma maculatum in one of them) are reported. two of the three cases were undoubtely produced by rickettsia conorii according to the results of the specific indirect immunofluorescence technique ief-igm anti r. conorii. a third case is included due to the clinical epidemiological similarity, the positive serum reactivity with proteus o x 19 and the rapid response to tetracycline. autochthonous ricketts ...19902135470
a comparative study of the infection thresholds of thogoto virus in rhipicephalus appendiculatus and amblyomma variegatum.infection thresholds of thogoto virus in 2 ixodid tick species, rhipicephalus appendiculatus and amblyomma variegatum, were compared. thogoto virus has been isolated from naturally infected r. appendiculatus and a. variegatum in central africa, where both commonly parasitize the same hosts. no significant difference was found between the infection thresholds of thogoto virus in the 2 species. the percentage of nymphs of both species infected by feeding on viremic hamsters was directly correlated ...19902166447
[prevention of cowdriosis and cases of sheep diseases in the niayes region of senegal].sheep originating from an heartwater-free area were immunized by the infection and treatment method, using long-acting oxytetracycline. the animals were then exposed, together with control sheep to natural infection in an enzootic area. tick counts were made to monitor the infestation and establish a correlation between infestation by certain tick species, in particular amblyomma variegatum, and the occurrence of cowdriosis. in some cases of death associated with ehrlichiosis and anaplasmosis in ...19902218032
[ticks and hemoparasitic diseases in cattle in senegal. iv. the southern sudan area].the authors report on the results of an investigation on ticks and hemoparasitoses of cattle, sheep and goats in the south sudanian area of senegal. systematic routine dipping against ticks of cattle, 40 sheep and 40 goats was set during 15 months, with a view to determine the population dynamics together with an acurate localization of the different species concerned. the following parasites were collected from these ruminants: amblyomma variegatum, boophilus geigyi, hyalomma truncatum, h. m. r ...19902218038
organ culture of ixodid-tick salivary glands.this work describes an organ-culture method for isolated salivary glands of the ixodid tick amblyomma hebraeum koch. the support medium is a tc 199-1% agarose gel with no hormonal or undefined supplements. i used a fluid-transport assay for measuring viability of salivary glands. when cultured at 26 degrees c, female glands secreted fluid at 65% on day 2, 59% on day 4 and 42% on day 6 post-culture compared to glands tested on day 0. fluid secretory rates in culture were higher than rates of glan ...19902226073
effect of 20-hydroxyecdysone on the salivary glands of the male tick, amblyomma hebraeum.female ticks (acari: ixodidae) feed only once in the adult stage, dying after laying a large batch of eggs. during the early post-engorgement stage, haemolymph ecdysteroid titre rises, which is probably responsible for autolysis of the salivary glands that takes place at this time. males, on the other hand, can re-attach and feed numerous times during the adult stage. males were fed on rabbits for either 7 or 14 days. haemolymph was collected either the day of removal from the host or 4 days lat ...19902226074
comparative efficiency of flagging and carbon dioxide-baited sticky traps for collecting the lone star tick, amblyomma americanum (acarina: ixodidae).collections of amblyomma americanum (l.) from five habitat types showed that significantly more ticks of all life stages could be collected by co2-baited sticky traps than by the standard flagging technique. the effect of habitat type and season significantly influenced the number of ticks collected by both techniques. traps baited with carbon dioxide revealed adult tick activity in several habitats several weeks earlier than did flagging, because flagging failed to efficiently recover ticks unl ...19902231613
comparative field evaluation of permethrin and deet-treated military uniforms for personal protection against ticks (acari).the effectiveness of permethrin-impregnated (pi) versus permethrin-sprayed (ps) military battle dress uniforms was evaluated in protecting soldiers from tick bite. at the same time, an extended-duration formulation of n,n-diethyl-m-toluamide (deet), when applied to clothing only, was evaluated and compared with the permethrin-treated uniforms. testing consisted of exposing subjects, clothed in either untreated or the variously treated uniforms, to field populations of ticks during a series of 30 ...19902231620
geographic occurrence of ixodes scapularis and amblyomma americanum (acari: ixodidae) infesting white-tailed deer in north carolina.a state-wide survey to determine the occurrence and comparative numbers of ticks infecting white-tailed deer (odocoileus virginianus) was conducted in north carolina (usa). one thousand six hundred twenty nine deer were examined in 60 of 100 counties; with the exception of one county in the piedmont region, all tick-infested deer occurred in the coastal plain. ixodes scapularis (46%) and amblyomma americanum (53%) were the most prevalent species encountered and accounted for more than 98% of the ...19902250335
[the taxonomic aspects of the transmission of the causative agent of lyme disease].according to world literature data 17 species of ixodid ticks have been studied for natural infection with the lyme disease agent. analysis of the data on the level of the infection, transovarial and transphase transmission has shown that main biological vectors of borrelia burgdorferi are the species of the subgenus ixodes s. str. - i. ricinus, i. persulcatus (eurasia), i. dammini, i. pacificus (north america). potential vectors are i. scapularis, i. dentatus, amblyomma americanum, dermacentor ...19902259524
population growth rates for amblyomma americanum (acari: ixodidae) on bos indicus, b. taurus and b. indicus x b. taurus cattle.densities of amblyomma americanum (l.) on bos indicus, b. taurus and b. indicus x b. taurus cattle are compared over a 3-year period, and the growth rate (rate of increase or decrease) of parasitic tick populations on each cattle genotype is estimated. average log10 densities of parasitic a. americanum larvae are significantly (p = 0.05) lower on b. indicus cattle than on b. taurus and b. indicus xb. taurus cattle. average log densities of nymphal and adult ticks on b. taurus cattle are signific ...19902261818
[ticks of the ixodidae family as reservoir of arboviruses in the republic of guinea. ii. arboviruses].from 1978 to 1985, 96,167 ixodidae family were collected, from which 79 strains of the following arboviruses were isolated, i.e. 4 bhanja strains, 9 chf-congo, 20 dugbe, 24 jos (viruses ecologically related to ticks), 10 abadina, 7 bluetongue, 1 bunyamwera, 1 chikungunya, (related to ticks for the first time), 1 kindia and 2 forecariah (new viruses). the main sources for arbovirus isolation were ticks of the amblyomma variegatum genus (78.5%) followed by ticks of the boophilus (12.6%), rhipiceph ...19902263738
efficacy of ivermectin delivered from an intraruminal sustained-release bolus against natural infestations of five african tick species on cattle.the efficacy of ivermectin delivered by an orally administered prototype sustained-release bolus over approximately 90 days was evaluated against natural infestations of five african tick species. twenty cattle, allocated by restricted randomization based on counts of standard boophilus decoloratus, were allocated to two groups and were either given an ivermectin bolus or designated as non-medicated controls. all cattle grazed a single pasture of native grasses for 20-40 days before treatment an ...19902267728
amblyomma variegatum and associated diseases in the caribbean: strategies for control and eradication in guadeloupe.amblyomma variegatum, introduced into guadelopue 150 years ago, has recently spread in the lesser antilles and threatens north america. two important diseases are associated with the tick: heartwater and dermatophilosis. heartwater occurs in guadeloupe, marie-galante and antigua; acute dermatophilosis exists almost everywhere the tick is present. both are very pathogenic for upgraded or newly-infested cattle. after 15 years of a. variegatum control in guadeloupe, a balance is established between ...19902284130
helminth and arthropod parasites of angora goats on irrigated kikuyu grass pastures in the eastern cape province.angora goat kids and yearlings grazing irrigated kikuyu (pennisetum clandestinum) grass pastures in the eastern cape province, became heavily infected with teladorsagia circumcincta and trichostrongylus rugatus, leading to high mortality in both age groups. peak burdens of the former were recorded during march and may, and of the latter during may and june. larger numbers of the cestode moniezia expanza, occurred in the kids than in the yearlings. despite the stress of high helminth burdens, no ...19902286996
increased pathogenicity of an ehrlichia-like agent after passage through amblyomma hebraeum: a preliminary report.after being passaged through 3 generations of amblyomma hebraeum, an ehrlichia-like agent isolated from an adult hyalomma truncatum female became more pathogenic and elicited a disease in sheep indistinguishable from heartwater. cross-immunity between this agent and several stocks of cowdria ruminantium and high levels of antibody elicited by the agent against 2 stocks of c. ruminantium in the indirect fluorescent antibody test, confirmed its close relationship to cowdria.19902293132
amblyomma americanum: identification of tick salivary gland antigens from unfed and early feeding females with comparisons to ixodes dammini and dermacentor variabilis.salivary gland antigens involved in host resistance to tick feeding by amblyomma americanum (lone star tick) have been identified. gland extracts from unfed and partially fed 12-, 48-, 72-, 96-, and 120-hr females and their corresponding midgut tissues were analyzed by immunoblotting with sera from naturally immune and hyperimmune sheep and rabbits. polypeptides at 90, 75, 58, 45, 33, and 23 kda from the salivary glands of a. americanum females were consistently observed with antibodies from bot ...19902298277
identification of babesia bovis and cowdria ruminantium on the island of unguja, zanzibar.babesia bovis and cowdria ruminantium were identified for the first time in cattle on unguja island, zanzibar. b bovis is common and widespread, although clinical disease had not been diagnosed previously. the vector of heartwater, amblyomma variegatum, is found throughout unguja but c ruminantium appears to be more localised in distribution than b bovis.19902301128
attempted transmission of ehrlichia risticii, causative agent of potomac horse fever, by the ticks, dermacentor variabilis, rhipicephalus sanguineus, ixodes scapularis and amblyomma americanum.dermacentor variabilis, rhipicephalus sanguineus, amblyomma americanum, and ixodes scapularis ticks were investigated for their ability to transmit potomac horse fever. larval and nymphal ticks were exposed to ehrlichia risticii by feeding on mice inoculated with the organism. molted exposed ticks were then allowed to feed on susceptible ponies or mice. no evidence of transmission, either clinically or by detection of antibodies to e. risticii in mice or ponies, was observed for any tick species ...19902307070
management of lone star ticks (acari: ixodidae) in recreational areas with acaricide applications, vegetative management, and exclusion of white-tailed deer.a project on management of lone star ticks, amblyomma americanum (l.), at land between the lakes, a tennessee valley authority recreational area in kentucky-tennessee, during 1984-1988, demonstrated the effectiveness and economics of three control technologies. acaricide applications (chlorpyrifos at 0.28 kg [ai]/ha), vegetative management (mowing and removal of 40% overstory and 90-100% of midstory, understory, and leaf litter), and host management (white-tailed deer exclusion from a 71-ha camp ...19901696994
detection of an arbovirus in an invertebrate and a vertebrate host using the polymerase chain reaction.the ability of the polymerase chain reaction (pcr) to diagnose an arboviral infection in an arthropod vector or a mammalian host was examined. dugbe (dug) viral rna was detected in rna extracts from infected tissue samples by reverse transcription and enzymatic amplification of the resulting cdna using taq dna polymerase, followed by characterisation of the amplified product by agarose gel electrophoresis or dot-blot hybridisation. viral rna was detected in the organs and haemolymph of infected ...19901707893
ticks (acari: ixodidae) of the nile monitor on rusinga island, the course of a study of ticks of livestock, five nile monitor lizard specimens were caught and examined for ticks. although none of the tick species infesting livestock were found on the reptiles, a large number of adults and presumed nymphs and larvae of aponomma flavomaculatum (lucus) and adults of amblyomma sparsum (neumann) were collected. the ticks demonstrated a distinct predilection for their attachment sites. this is the second report of a. flavomaculatum from this part of kenya.19902332875
histological reactions to bites of amblyomma variagatum and rhipicephalus appendiculatus (acari: ixodidae) fed simultaneously on naive or sensitized rabbits.histopathological studies on attachment sites of nymphs, 48 h after attachment on three groups of rabbits, have revealed differences that were related to the rabbits' previous tick experience. feeding lesions caused by amblyomma variegatum (f.) in tick-naive rabbits were extensive and the total number of inflammatory cells was about 10 times greater than that in the feeding lesions caused by rhipicephalus appendiculatus neumann fed simultaneously on contralateral ears. rabbits that were previous ...19902332876
resistance of brahman and simmentaler cattle to southern african ticks.field collections of ticks from two breeds of cattle in the north western transvaal showed the common tick species to be rhipicephalus appendiculatus, amblyomma hebraeum, rhipicephalus evertsi evertsi and hyalomma marginatum rufipes. the number of these ticks was higher on simmentaler than on brahman cattle. correlation was found between the number of ticks on the cattle and their serum gamma globulin levels indicating an increase in the production of antibodies. similar correlation was also fou ...19902339000
ecological aspects of four species of ticks found on cattle in salta, northwest argentina.the seasonal activity of amblyomma cajennense, amblyomma neumanni, amblyomma parvum and boophilus microplus on cattle was studied in a ranch located in the northern part of the phytogeographical district of the chaco serrano where the habitat had suffered minimal human disturbance. the female ticks on one side of 10-25 cows were counted at intervals of 20-50 days from 29 october 1985 to 5 november 1986. the percentage of cattle parasitized with larvae and nymphs of amblyomma was recorded, along ...19902343535
ecology and phenology of cattle ticks in zambia: development and survival of free-living stages.a study on development and survival of free-living stages of three important cattle ticks in zambia, amblyomma variegatum fabricus, boophilus decoloratus koch, and rhipicephalus appendiculatus neumann, was carried out to complement studies on seasonal dynamics of parasitic stages. different instars of engorged ticks were exposed under quasi-natural conditions according to the season in which they occur naturally. generally, development rates of all stages of the three species were related to tem ...19902350995
experimental transmission of a granulocytic form of the tribe ehrlichieae by dermacentor variabilis and amblyomma americanum to dogs.transstadial transmission of granulocytic ehrlichieae in dogs was attempted using ticks, amblyomma americanum and dermacentor variabilis. ticks were exposed by feeding as nymphs on acutely infected pups; adult ticks then fed to repletion on susceptible adult dogs that were monitored daily for signs of infection. evidence of transmission was not observed in control dogs or in those exposed to d variabilis. in contrast, dogs exposed to a americanum developed serologic or clinical evidence of infec ...19902368951
rickettsia in texas.since the first reported case in 1941, rocky mountain spotted fever in humans has been reported from many areas of texas, with two major foci, one located in the north-central region and the other in the eastern region of the state. during the period 1979-1988, 421 cases of rmsf were reported, reaching 108 cases in 1983 and declining in subsequent years. statewide surveillance programs to detect spotted fever group rickettsiae in tick populations were initiated in 1976. in recent years, the sfg ...19902378448
ectoparasitic and phoretic arthropods of virginia opossums (didelphis virginiana) in central tennessee.thirteen species of ectoparasitic (12) or phoretic (1) arthropods were collected from 26 adult virginia opossums, didelphis virginiana, live-trapped from april through september 1987 in davidson county, tennessee. the cat flea ctenocephalides felis and the american dog tick dermacentor variabilis were the predominant species with respect to mean intensity and prevalence. the macronyssid mite ornithonyssus wernecki and the atopomelid mite didelphilichus serrifer, both specific parasites of this h ...19902380870
effects of sequential infestations of dermacentor albipictus and amblyomma americanum (acari: ixodidae) on overwintering beef cows in west-central texas.infestations of winter ticks, dermacentor albipictus (packard), observed on mature black angus cows, reached peak levels in january and diminished through march. infestations of adult lone star ticks, amblyomma americanum (l.), began in mid-january and increased through may. cows receiving ectrin, taktic, or deltox treatments on 13 december and 21 february experienced significantly less weight loss and entered the subsequent breeding season with higher average body weight than untreated cows. in ...19902388237
intrinsic competence of three ixodid ticks (acari) as vectors of the lyme disease spirochete.we compared the intrinsic vector competence of ixodes dammini spielman et al., dermacentor variabilis (say), and amblyomma americanum (l.) for the lyme disease spirochete (borrelia burgdorferi johnson et al.) on prudence island, rhode island, a lyme disease-endemic site where all three ticks occur together. natural and experimental spirochete infection rates were determined in those ticks and their degree of contact with white-footed mice (peromyscus leucopus), the principal reservoir host, was ...19902388239
infection rates with cowdria ruminantium of nymphs and adults of the bont tick amblyomma hebraeum collected in the field in zimbabwe.cowdria ruminantium (heatwater) infection rates of field populations of the bont tick, amblyomma hebraeum, were determined at two locations in the southern lowveld of zimbabwe. at mbizi quarantine station, unfed adult males and females, and nymphs were collected at intervals over a 2-year period using traps. at lemco ranch, engorged nymphs were collected on three occasions from weaner calves and allowed to moult to adults. the unfed ticks were fed in small pools on heartwater-susceptible sheep, ...19902399648
acute dermatitis caused by amblyomma variegatum larvae on chickens.acute dermatitis caused by amblyomma variegatum larvae infestation was observed in adult local nigerian chickens. skin lesions containing numerous a. variegatum larvae were observed on gross examination. histopathology showed skin haemorrhages, larvae, necrosis and infiltration of eosinophils. it was suspected that the free range life of the birds could have predisposed them to the infestation.199018679988
[dermatophilus congolensis bovine dermatophilosis in the french west indies. iii. a comparison between infected and non-infected cattle].the determination of the distinctive features between infected and uninfected cattle by dermatophilus has been performed among 93 bovine stock in la martinique, and 120 in la guadeloupe and saint-martin islands. nearly half of the herds had been or were infected. morbidity rates reach 33 per cent in la martinique and 29 per cent in la guadeloupe with a mortality ratio of 15 per cent and 5 per cent respectively. no frequency difference could be observed with respect to the season or the geographi ...19892485539
experimental studies on the replication and transmission of crimean-congo hemorrhagic fever virus in some african tick african tick species were studied as potential vectors of crimean-congo hemorrhagic fever (cchf) virus. engorged nymphae of 4 ixodid species, hyalomma marginatum rufipes, h. truncatum, rhipicephalus evertsi mimeticus, and amblyomma hebraeum, were inoculated intracoelomically with cchf virus and assayed for virus content at varying times post-inoculation. the virus replicated in all 4 species, reaching maximum titers of 4.6-5.5(10) fluorescence focus units per ml on days 5-9 post-inoculatio ...19892494900
experimental infection of six species of ixodid ticks with dugbe virus (family bunyaviridae, genus nairovirus).the vector potential of each of 6 species of colonized north american and african ixodid ticks was assessed by intracoelomic inoculation with dugbe virus (ibar 1792, 14th passage in suckling mouse brain) and viral titers were monitored after selected incubation periods. persistence of dugbe virus for greater than or equal to 53 days in 5 species (dermacentor andersoni, d. variabilis, amblyomma americanum, rhipicephalus appendiculatus, and r. sanguineus) indicates that infection occurred. viral t ...19892496609
ectoparasitic acari found on golden lion tamarins (leontopithecus rosalia rosalia) from brazil.anesthetized golden lion tamarins (leontopithecus rosalia rosalia), a highly endangered species, were examined for ectoparasites by brushing the fur and swabbing the ears. ectoparasites recovered from the fur included four species of immature ticks (amblyomma spp.), three species of chiggers (euschoengastia sp., microtrombicula brennani and speleocola tamarina), and one species of follicular mite (rhyncoptes anastosi). ectoparasites do not seem to be of particular significance to the health of t ...19892503627
difference in vector competence of two species of sympatric ticks, amblyomma variegatum and rhipicephalus appendiculatus, for dugbe virus (nairovirus, bunyaviridae).amblyomma variegatum was shown to be a competent vector of dugbe (dug) virus whereas rhipicephalus appendiculatus was not. when dug virus was taken up orally by a. variegatum nymphs, during capillary feeding, the virus replicated and persisted through moulting to the following adult stage. in contrast, although dug virus replicated in capillary fed r. appendiculatus nymphs, the virus did not persist trans-stadially into the adult stage. if the oral route of infection was by-passed by direct inoc ...19892510418
vector capacity of rhipicephalus appendiculatus and amblyomma variegatum for thogoto and dhori viruses.experimental studies were undertaken to ascertain the vector potential of rhipicephalus appendiculatus neumann and amblyomma variegatum fabricius for thogoto (tho) and dhori (dho) viruses, candidate members of the orthomyxoviridae. in the first set of experiments, ticks were infected orally by feeding on viraemic hamsters. tho virus replicated in r. appendiculatus and a. variegatum, persisted trans-stadially in both tick species, and was transmitted to susceptible hosts during feeding. in contra ...19892519663
ecological aspects of cattle tick control in central ecological studies in central zambia, both climate and ecotype affected population dynamics of tick species. below average rainfall for several years caused a suppression in numbers of rhipicephalus appendiculatus neumann adults. reduction in rainfall leading to changes in grazing patterns is thought to have been responsible for an increase in numbers of amblyomma variegatum fabricius adults in a grassland habitat. there were reasonable correlations between numbers of each tick species on ind ...19892519677
effect of tick control on liveweight gain of cattle in central zambia.field trials were carried out during 1982-86 in two different ecotypes in central zambia to determine the impact of tick control on the liveweight gain (lwg) of cattle. during the first 2 years of the trial a diamidide acaricide (amitraz) sprayed at weekly intervals caused periodic depression in lwg in young animals. thereafter a pyrethroid acaricide (cypermethrin) was used. during the 1984-85 tick season infestations of 50-120 adult amblyomma variegatum fabricius in untreated animals caused sig ...19892519678
resistance and cross-resistance in guinea-pigs and rabbits to immature stages of ixodid ticks.infestation of guinea-pigs and rabbits with larvae of any one of five species of ticks, rhipicephalus appendiculatus neumann, rhipicephalus evertsi evertsi neumann, amblyomma hebrauem koch, amblyomma variegatum fabricius and ixodes ricinus l., conferred resistance in the animals when exposed to subsequent infestations with the same tick species. resistance to infestations by other tick species was not observed.19892519683
the role of males of the bont tick (amblyomma hebraeum) in the transmission of cowdria ruminantium (heartwater).the role of males of the bont tick (amblyomma hebraeum) in the transmission of cowdria ruminantium (heartwater) was investigated. transstadial (nymph to adult) and intrastadial transmission were demonstrated. males transferred from live or dead hosts to live hosts were shown to transmit c. ruminantium repeatedly. it was concluded that male transmission is of importance in the epidemiology of heartwater.19892588467
control of lone star ticks (acari: ixodidae) on spanish goats and white-tailed deer with orally administered ivermectin.ivermectin administered orally to spanish goats, capra hircus (l.), or to white-tailed deer, odocoileus virginianus (zimmerman), was highly effective against lone star ticks, amblyomma americanum (l.). for spanish goats, daily oral doses of 20 micrograms/kg resulted in greater than or equal to 2 ppb ivermectin in the blood. this level was sufficient to cause greater than 95% reduction of estimated larvae from feeding ticks. a bioassay with horn flies, haematobia irritans (l.), was developed to e ...19892607030
[the efficacy of alphamethrin-impregnated ear tags against ticks].the efficacy of 3 kinds of alphamethrin-impregnated ear tags was tested against natural amblyomma hebraeum, boophilus decoloratus, rhipicephalus appendiculatus, and rhipicephalus evertsi evertsi infestations of cattle. one type of ear tag was also tested in combination with a tail band of similar material. ticks were counted macroscopically on their predilection sites. counts of b. decoloratus, r. appendiculatus, and r. e. evertsi on all trial animals diminished steadily during the first 7d afte ...19892607535
the carrier status of sheep, cattle and african buffalo recovered from heartwater.sheep, cattle and the african buffalo (syncerus caffer) were shown to remain carriers of heart-water (caused by cowdria ruminantium) for long periods after recovery; 223, 246 and 161 days, respectively. transmission was achieved using adults of the southern african bont tick (amblyomma hebraeum) that had fed as nymphs on recovered animals. our findings differ from those of other workers who attempted transmission using nymphs that had fed as larvae on recovered animals or with blood from recover ...19892617830
parasite survey of eight wild animals in the ruma national park.eight game animals representing seven species in the ruma national park in south nyanza, kenya, were examined for the presence of blood protozoa, ectoparasites, and helminthic and coccidian endoparasites using standard parasite-identification methods. haematological parameters were also determined. the oribi was positive for trypanosoma brucei ssp. and the reedbuck for t. congolense. no other blood protozoans were found. strongyle eggs were found in the faeces of all species except the water buc ...19892619384
resistance of nguni, bonsmara and hereford cattle to ticks in a bushveld region of south africa.counts of engorged female ticks on naturally infested cattle over a 2 year period, showed that indigenous nguni cattle harboured significantly fewer amblyomma hebraeum, boophilus decoloratus and hyalomma spp. during periods of peak abundance than either bonsmara or hereford cattle. fewer abscesses, associated with tick bite, were also present in the nguni cattle. individual tick resistance indices, determined after artificial tick infestation in the field, could not be correlated with hair lengt ...19892626263
the host status of the striped mouse, rhabdomys pumilio, in relation to the tick vectors of heartwater in south africa.striped mice, rhabdomys pumilio, were trapped over a 17 month period in the thomas baines nature reserve in the eastern cape province of south africa. captured mice were placed in cages, over water, and naturally detaching ticks were collected. only 5 larvae and 1 nymph of amblyomma hebraeum were recovered from the mice. these represented less than 0.1% of the total number of ticks recovered. no amblyomma marmoreum were recovered. as the vegetation and large mammals and tortoises in the thomas b ...19892626267
transmission of lyme disease spirochetes (borrelia burgdorferi).the field and laboratory evidence incriminating nymphal ixodes dammini as the main vectors of borrelia burgdorferi is substantial. furthermore, other members of the ixodes (ixodes) ricinus 'complex', including i. ricinus, i. persulcatus, i. pacificus, and i. scapularis, are competent vectors of the lyme disease spirochete. although ticks in other genera are also naturally infected with b. burgdorferi, experimental evidence suggests that amblyomma and dermacentor ticks are inefficient vectors of ...19892667921
[the coevolution of ixodid ticks and terrestrial vertebrates].paleontologic and zoogeographic data speak in favour of mesozoic origin of ixodid ticks. the absence of strict restrictions for the feeding on unusual species of hosts has caused the domination of polyphagy and oligophagy over monophagy among ixodid ticks. the same peculiarities of ixodid ecology are responsible for a restricted part or absence of phylogenetic parallelism with hosts in their evolution. primary food relations with reptiles are, apparently, preserved only in the genus aponomma and ...19892694077
a mouse lethal dose assay for detection and titration of cowdria ruminantium (kwanyanga strain) in goats and ticks.a mouse lethal dose assay was used to detect a mouse pathogenic strain (kwanyanga) of cowdria ruminantium, the etiological agent of heartwater in goats and ticks. the titer of the rickettsial organisms in goat blood was directly related to the febrile response of the goat and the rickettsia were undetectable after the fever subsided. the maximum rickettsial titer in goat blood was 10(3) mouse ld50 ml-1. cowdria-infected goat blood was shown to retain infectivity when held on ice for up to 2 h, b ...19892705290
evaluation of the eradication program for amblyomma variegatum (acari:ixodidae) on puerto rico.a cooperative effort between the united states department of agriculture, animal and plant health inspection service, veterinary services, the agricultural research service, and the department of agriculture, commonwealth government of puerto rico has been successful in eradicating amblyomma variegatum (fabricius) from the islands of puerto rico and vieques (an island municipality of puerto rico). application of acaricides to livestock and dogs at 14-day intervals for an 18-month period eliminat ...19892707108
sites of attachment and density assessment in amblyomma americanum (acari: ixodidae) on nursing beef calves.primary attachment sites of male, female, and nymphal amblyomma americanum (l.) on nursing beef calves were the axillary, inguinal and perianal areas of the body. about 50% of all larvae fed on the ears. a density assessment method which uses the number of a. americanum on less than or equal to 5 body areas to predict the total number of ticks (tick burden) on the left side of a calf is presented. estimates of tick burden for male, female, nymphal and larval a. americanum each require examinatio ...19892714123
spectral sensitivity, absolute threshold, and visual field of two tick species, hyalomma dromedarii and amblyomma variegatum.1. the spectral sensitivity in the wavelength range of 340-750 nm was determined by both a behavioral approach based on spontaneous positive phototaxis and the electroretinogram (erg). 2. concerning phototaxis the camel tick, hyalomma dromedarii, showed two sensitivity maxima, one in the uv range (ca. 380 nm) and another in the blue-green range (ca. 500 nm). at higher intensities the relative sensitivity was more pronounced in the uv and at lower intensities more pronounced in the blue-green (re ...19892746548
habitat use by cattle affects host contact with lone star ticks (acari: ixodidae).the location of zebu, british, and zebu x british cattle in tick-infested plots from march through september 1986 was compared with the location of amblyomma americanum l. in the same plots. in april, may, and june, zebu cattle spent less time (9.3-19.4%) in tick-infested quadrats than british (44.4-63.9%) or zebu-british (49.0-69.3%) cattle. in the same months, the probability that a. americanum would contact zebu cattle (1.5-19.6%) was significantly lower than for british (34.7-41.7%) or zebu- ...19892754101
characterization of ixodid tick salivary-gland gene products, using recombinant dna technology.ticks secrete an array of lesion-maintenance factors into the host via the salivary glands while feeding, some of which elicit an immune response by the host that adversely affects the ability of the tick to feed and reproduce. our approach to characterizing these factors has been to make expression libraries from mrna of salivary glands (from unfed and 3-day-feeding amblyomma americanum females) which will serve as sources of the genes (clones) that code for them. thus far, we have detected 10 ...19892758938
acquired resistance to ixodid ticks induced by tick cement antigen.antisera from guinea pigs made resistant to infestation with an ixodid tick of east and central africa, rhipicephalus appendiculatus, were used to identify the tick antigens they recognized by immunoblotting. most of the antigens were found in tick salivary glands and in tick attachment cement. antisera from r. appendiculatus-resistant guinea pigs also recognized some salivary-gland antigens in ticks of other species (r. pulchellus, r. evertsi, amblyomma variegatum and a. gemma). antibodies agai ...19892758939
amblyomma variegatum ticks and the occurrence of bovine streptothricosis in antigua.the association between the occurrence of amblyomma variegatum ticks and streptothricosis was studied on the caribbean island of antigua. the prevalence of streptothricosis was higher on animals having a. variegatum ticks compared to that of animals not infested with a. variegatum ticks. there was a steady increase in the prevalence of severe lesions as the level of infestation with adult a. variegatum ticks increased. however the distribution of skin lesions could not be related to the predilec ...19892763757
monitoring of naturally acquired and artificially induced immunity to amblyomma variegatum and rhipicephalus appendiculatus ticks under field and laboratory conditions.the ability of rabbits, goats and cattle to acquire immunity to the ixodid ticks amblyomma variegatum and rhipicephalus appendiculatus was studied under laboratory and field conditions. rabbits were successfully immunized with crude salivary gland extract (sge) and midgut extract (me) obtained from flat or partly fed female r. appendiculatus ticks. the lowest numbers of larvae were produced by females fed on rabbits immunized with unfed midgut extract. similar reductions in larval production cou ...19892766896
polyfluoro 1,3-diketones as systemic insecticides.a series of aryl polyfluoro 1,3-diketones were examined for systemic ectoparasiticidal activity in cattle. the compounds demonstrated efficacy against several economically important species of insects and acarina. at dosages of 5 mg/kg x1 or 0.35 mg/kg per day intraruminally, activity was observed against blowfly larvae (phormia regina), adult stable fly (stomoxys calcitrans), and lone star tick (amblyomma americanum). in vivo activity was not directly related to in vitro activity, showing a str ...19892769686
female mediation of feeding time on cattle in adult lone star ticks (acari: ixodidae).the extended feeding time response on cattle of adult lone star ticks, amblyomma americanum (l.), during november through december is facultative and is mediated by the female. mean feeding time (11.8 d) in female ticks taken from the field and held at 14:10 (l:d) photoperiod and 25 degrees c for greater than or equal to 15 d was significantly shorter (p = 0.05) than for females taken directly from the field and fed on cattle (14.6 d). mean feeding times of females from the field paired to males ...19892769719
dugbe virus replication in nymph and adult amblyomma variegatum. 19892772415
delayed-type hypersensitivity test for assessing tick-immune status of cattle in zambia.delayed-type hypersensitivity skin reactions were used to assess the tick resistance status of tonga calves in zambia. the antigen used in the tests was a homogenate of unfed nymphal rhipicephalus appendiculatus which had been shown to give protective immunity in guinea pigs to adult female r appendiculatus. there was a significant negative correlation between the intensity of the reactions and the total number of ticks (amblyomma variegatum, r appendiculatus, hyalomma truncatum, boophilus decol ...19892773195
pericarditis associated with tick-borne q fever.a case of pericarditis associated with q fever is described. transmission was probably via an arthropod vector, which was most likely the kangaroo tick amblyomma triguttatum. complete recovery occurred in association with the use of non-steroidal anti-inflammatory agents only. this is a rare presentation of q fever implicating transmission by a novel vector.19892775046
pictorial key to the adults of hard ticks, family ixodidae (ixodida: ixodoidea), east of the mississippi river.six genera and 27 species of hard ticks (ixodidae) currently are recognized in the united states east of the mississippi river as follows: amblyomma (4 species), boophilus (1), dermacentor (3), haemaphysalis (2), ixodes (16), and rhipicephalus (1). we present a diagrammatic couplet key to the adults of the six genera and 27 species of ixodidae found in the eastern portion of the united states.19892795615
reduction of the amblyomma americanum (acari: ixodidae) population at fort a.p. hill, virginia, by aerial application of diazinon granules: correlation of percentage control with received dose.habitat (280 ha) of lone star tick, amblyomma americanum (l.), was aerially treated with 14% diazinon granules. concentration of acaricide reaching the forest floor ranged from 0.02 to 1.25 kg (ai)/ha. greater than 85% control was achieved at study plots receiving the highest dose. a positive correlation was shown between dose received at the forest floor and percentage of control of adults (r = 0.91) and nymphs (r = 0.86).19892795622
comparison of flagging, walking, trapping, and collecting from hosts as sampling methods for northern deer ticks, ixodes dammini, and lone-star ticks, amblyomma americanum (acari:ixodidae).ticks were sampled by flagging, collecting from the investigator's clothing (walking samples), trapping with dry-ice bait, and collecting from mammal hosts on fire island, ny, u.s.a. the habitat distribution of adult deer ticks, ixodes dammini, was the same in simultaneous collections from the investigator's clothing and from muslin flags. walking and flagging samples can both be biased by differences between investigators, so the same person should do comparative samples whenever possible. walk ...19892806016
amblyomma marmoreum on tortoises of southern province, zambia.reptiles from southern province, zambia were captured and inspected for ticks. seven of 18 tortoises (geochelone pardalis) were infested by small numbers of adults and nymphs of amblyomma marmoreum. under such circumstances, the tick had little apparent effect on the host. none of the 13 specimens representing four species of snakes examined were infested with ticks.19892810567
[ticks of the family ixodidae in guinea and the isolation of arboviruses from them. ii. results of virologic and serologic research].55697 ixodidae ticks of 35 species, belonging to 7 genera, were collected in guinea in 1981-1983. virological study of 29410 ticks was performed by intracerebral infection of newborn white mice. 49 viral strains were isolated. authors identified 38 strains of the 8 following arboviruses: dugbe, bhanja, cgl-congo (ecologically connected with ticks), blue tongue virus of sheep and abadine (association with ticks was found for the first time), kindia and forekarya (the new viruses). serological scr ...19892811754
the effect of the bont tick (amblyomma hebraeum) on the weight gain of africander steers.the effects of the bont tick amblyomma hebraeum on the productivity of cattle need to be quantified in order to design economically optimal control programs. liveweight gains (lwgs) of three groups of africander steers, maintained in the same pasture and exposed to zero, medium or high numbers of larvae, nymphs and adults of the tick, were measured. larvae and nymphs had no significant effect on lwg but adults had a large, statistically significant effect (p less than 0.05). the tick-free group ...19892815542
pheromone-mediation of host-selection in bont ticks (amblyomma hebraeum koch).the bont tick, amblyomma hebraeum, is the principal vector to southern african ruminants of heartwater (cowdria ruminantium infection). the role of feeding male ticks, which emit an aggregation-attachment pheromone, in attracting unfed ticks to cattle was investigated. calves infested with feeding male ticks were more attractive to unfed adult ticks than were uninfested calves. the presence of the pheromone on previously infested cattle apparently allows unfed ticks to discriminate between hosts ...19892911745
effect of age on cholinesterase activity and protein of unfed larval ticks.the cholinesterase (ache) activity and total protein in homogenates of unfed larvae of amblyomma americanum (l.), a. cajennense (fabricius), a. maculatum koch, anocentor nitens neumann, and boophilus microplus (canestrini) were determined weekly in ticks 1-6 wk of age. there was a considerable variation in total protein, ache, and the ratio of ache to protein as the ticks aged. however, ache activities were constant or increased with age and total protein levels were constant or decreased. no di ...19892918444
comparison of the isozyme phenotypes of the morphologically similar ticks amblyomma cajennense and a. imitator (acari: ixodidae) from south texas.a survey of amblyomma koch tick populations in southern texas revealed that a. imitator kohls was restricted to the two most southern counties, but that a. cajennense (fabricius) ranged at least as far north as kingsville, tex. females of the two species could be distinguished by the presence of chitinous tubercles on the festoons of a. cajennense and the presence of projections over both sides of the apron of the genital aperture in a. imitator. males were distinguished by size, ornamentation, ...19892926774
[interrelatio of acari ixodidae and hosts of edentata of the serra da canastra, minas gerais, brazil].we received for examination a small colection of ticks captured in the national park of the serra da canastra (mg), between 1979 and 1980. the authors demonstrated the existence of a broad co-accomodation of amblyomma pseudoconcolor on edentata of the family dasypodidae, being dasypodini the tribe more adjusted to this infestation. in conformity to the figs 1 and 2, dasypodini are probably the real hosts of a. pseudoconcolor and also the oldest hosts. for the first time, a. pseudoconcolor is als ...19892319951
morphogenetic diapause in amblyomma variegatum (acari: ixodidae).in southern africa, amblyomma variegatum fabricius is characterized by a strict seasonal activity. experiments were carried out to determine whether a diapause mechanism regulates this seasonality. engorged a.variegatum females were exposed to controlled laboratory conditions or natural field conditions at different times of the year. females exposed in a natural environment in september-october (short day) had significantly longer pre-oviposition periods than females exposed from november to ma ...19882980187
hosts and population dynamics of amblyomma variegatum (acari: ixodidae) on guadeloupe, french west indies. 19883351867
abnormal development of amblyomma variegatum (acarina: ixodidae). 19883351871
the developmental success of amblyomma hebraeum and amblyomma marmoreum on the leopard tortoise, geochelone pardalis.the success of natural infestations of various life history stages of amblyomma hebraeum and amblyomma marmoreum on the leopard tortoise, geochelone pardalis, was compared. success was measured by the time taken for ticks to detach, as well as the percentage of ticks engorging and subsequently either moulting to the next life history stage or laying viable eggs. larvae of a. hebraeum were the only developmental stage not recovered. nymphae and female a. hebraeum were less successful in moulting ...19883353093
the use of domestic chickens as laboratory hosts of the larvae of the bont tick, amblyomma hebraeum.a comparison of attachment, engorgement and moulting success of amblyomma hebraeum larvae fed on domestic chickens and himalayan giant white rabbits indicates that chickens are better hosts than the rabbits. moreover the time needed for detachment of all engorged larvae is significantly less for chickens than for the rabbits. no evidence of induced immunity was found in chickens on re-infestation with larvae of a. hebraeum.19883353104
seasonal changes in feeding on cattle and reproduction by amblyomma americanum (acari: ixodidae) under field conditions. 19883357171
ticks parasitising the indian buffalo (bubalus bubalis) and their possible role in disease transmission.a total of 13 ixodid tick species, boophilus microplus, haemaphysalis bispinosa, haemaphysalis cornupunctata, haemaphysalis himalaya, heamaphysalis montgomeryi, hyalomma anatolicum anatolicum, hyalomma dromedarii, hyalomma marginatum isaaci, hyalomma (hyalommina) brevipunctata, hyalomma (hyalommina) hussaini, nosomma monstrosum, rhipicephalus haemaphysaloides, and r. turanicus were collected off 424 buffaloes from the northwestern states of india. ten tick species, amblyomma testudinarium, b. mi ...19883369083
kinetic properties of toxic protease inhibitors isolated from tick eggs.1. egg-toxins from rhipicephalus evertsi evertsi, boophilus microplus, boophilus decoloratus and hyalomma truncatum were found to be inhibitors of trypsin and in two cases also of chymotrypsin. 2. fast tight-binding and slow-binding inhibition were observed. 3. immunological identity of the toxins were assessed with ouchterlony immunodiffusion and elisa. 4. the protease content of b. decoloratus and amblyomma hebraeum tick eggs were determined by a linked enzyme assay. 5. the predictive value of ...19883391338
evidence for regurgitation by amblyomma americanum.western blot analysis of amblyomma americanum-derived midgut extracts using tick-resistant rabbit and guinea pig antisera demonstrated several unique polypeptides ranging from 7 to 355 kda. these polypeptides were not observed in similar blots of salivary gland extracts or serum from the respective host animals. the data from this study suggest that female a. americanum ticks regurgitate gut material during feeding. such a finding explains the ability of immunization with gut-derived preparation ...19883420794
field sampling of unfed nymphs of amblyomma hebraeum.unfed nymphs of amblyomma hebraeum koch, 1844 shelter under debris on the soil surface and become active in host-seeking when stimulated with carbon dioxide. the active nymphs are not attracted to sources of carbon dioxide and hence cannot be effectively sampled using static carbon dioxide traps. however, these nymphs will cling to flannelette and can be sampled by flagging. larger numbers are recovered if the soil surface is sampled using a vacuum device.19883137010
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