TitleAbstractYear(sorted ascending)
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
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
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
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
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
tick infestations of white-tailed deer in alabama.four species of ticks were collected from 537 white-tailed deer (odocoileus virginianus), examined during the hunting seasons (november to january) of 1988-89 and 1989-90 at selected locations in alabama (usa). ixodes scapularis was the most common tick recovered (2,060 specimens) and infested 54% of the deer. dermacentor albipictus was the second most frequent tick (1,253 specimens) and infested 15% of the deer. amblyomma americanum was the third most frequent tick (315 specimens) and infested ...19911758026
rectal infusion and aspiration of material through the guts of ixodid ticks (acari: ixodidae).a technique for inoculating and removing substances via the anus of vector ticks was devised to define features of vector competence precisely. calibrated inocula (greater than 5 nanoliter) containing aqueous dye and polystyrene beads as well as infectious agents were infused into the rectal sacs of ticks using glass microcapillary pipettes placed within the expanded anal orifice. the guts of preadult and adult ticks, ixodes dammini spielman, clifford, piesman & corwin, dermacentor variabilis (s ...19911770516
predators of the tick amblyomma variegatum (acari: ixodidae) in guadeloupe, french west indies.some vertebrate species in guadeloupe are predators of free or parasitic stages of amblyomma variegatum (fabricius). among birds, 1.9% of the 421 identified animals found in the stomachs of grackles (quiscalus lugubris), 1.6% of the 364 animals found in the stomachs of free-ranging chickens, and 0.3% of the 4642 animals found in the stomach of cattle egrets (bubulcus ibis) were a. variegatum ticks. the most efficient predator of ticks was the tropical fire ant, solenopsis geminata, which was obs ...19911773677
acaricide susceptibility of amblyomma variegatum (acari:ixodidae) from puerto rico and guadeloupe.base-line data on acaricide susceptibility of larvae and of larvae and nymphs of the tropical bont tick, amblyomma variegatum (fabricius), from puerto rico and guadeloupe were collected on 14 and six compounds, respectively. nymphs 7-8 weeks old from puerto rico and guadeloupe, and larvae 3-4 weeks old from guadeloupe, were exposed for 24 or 48 h to residues of acetone dilutions of technical-grade or commercial formulations of acaricides on disposable glass pipettes. effectiveness of the acarici ...19911773678
resistance of indigenous african cattle to the tick amblyomma hebraeum.field collections of amblyomma hebraeum koch adults from six breeds of cattle were conducted on two farms in the northern transvaal. the density of a. hebraeum adults was highest on simmentaler cows, followed by santa gertrudis, africaner, bonsmara, brahman and nguni. indigenous breeds, namely nguni, bonsmara and africaner, have the highest level of resistance to a. hebraeum. the relationship between tick abundance and the high level of resistance found in the indigenous breeds is discussed.19911773680
a cloned dna probe identifies cowdria ruminantium in amblyomma variegatum ticks.heartwater, caused by cowdria ruminantium and transmitted by ticks of the genus amblyomma, is a constraint to ruminant animal production in sub-saharan africa. this rickettsial disease could spread from endemically infected areas of sub-saharan africa and certain caribbean islands to other countries, including the united states, in which amblyomma ticks exist. to detect c. ruminantium in tick vectors and animals, we made dna probes from c. ruminantium dna isolated from endothelial cell cultures. ...19911774264
parasites of domestic and wild animals in south africa. xxix. ixodid ticks on hares in the cape province and on hares and red rock rabbits in the orange free hundred and seventeen scrub hares, lepus saxatilis, were examined for ixodid ticks in various regions of the cape province. they were infested with 18 tick species and the seasonal abundances of the immature stages of amblyomma hebraeum, amblyomma marmoreum, hyalomma marginatum rufipes, rhipicephalus appendiculatus and rhipicephalus glabroscutatum and all stages of rhipicephalus oculatus and the adults of a rhipicephalus sp. (near r. oculatus) were determined. seventy-two scrub hares on 3 fa ...19911780126
transient infections of goats with a novel spotted fever group rickettsia from zimbabwe.a novel spotted fever group rickettsia has recently been isolated from amblyomma hebraeum ticks in zimbabwe. in a survey of 172 goat sera collected throughout zimbabwe the highest prevalence of antibodies reactive with this rickettsia was in the south of the country, the area where a hebraeum is most commonly found. nine goats were infected using male and female a hebraeum taken from a tick line shown to be infected with the novel rickettsia. by week 3 after infection, seroconversion occurred in ...19911780580
the life cycle of amblyomma parvum aragao, 1908 (acari: ixodidae) under laboratory conditions.a colony of amblyomma parvum was started with engorged females collected from cattle in the province of salta (25 degrees 01' s, 63 degrees 56' w), argentina. the progeny of those ticks were fed on rabbits and the non-parasitic stages maintained at 27 +/- 1 degrees c, 83-86% rh in darkness. the life cycle (prefeeding period not evaluated) had a mean duration of 99.6 days. the mean time (days) for the different phases of the cycle were as follows: feeding period of females, 8.0; pre-oviposition p ...19911786743
comparison of known and suspected pheromonal constituents in males of african ticks, amblyomma hebraeum koch and amblyomma variegatum (fabricius).three low molecular weight compounds were found in hexane:diethyl ether extracts of fed males of the african ticks, amblyomma variegatum (tropical bont tick) and a. hebraeum (bont tick), namely, o-nitrophenol, methyl salicylate and 2,6-dichlorophenol. these same compounds were also fond in a rinse of fed a. variegatum males, but were absent or present in only trace amounts in a rinse of fed a. hebraeum males, o-nitrophenol and methyl salicylate were present in much higher concentrations (i.e., a ...19911786745
seasonal occurrence of the bont tick (amblyomma hebraeum) in the southern lowveld of zimbabwe.the seasonal occurrence of the bont tick amblyomma hebraeum was recorded over 2 years on 20 brahman cattle held in a 240-ha paddock at mbizi in southeastern zimbabwe. the cattle were infested with all life cycle stages throughout the study period, and no clearly defined seasonal patterns were recorded. males remained attached for up to about 6 months, and consequently accumulated on the cattle and outnumbered females considerably. the cattle did not acquire resistance to a. hebraeum and the abun ...19911786747
a comparison of the reproductive parameters of females of two reptile tick comparisons of females of two reptile tick species aponomma hydrosauri and amblyomma limbatum, ap. hydrosauri was initially larger, and after mating on the host engorged faster and remained attached for a shorter time before completing engorgement and detaching. amb. limbatum had a longer period of engorgement, and achieved a greater engorged weight. engorged amb. limbatum females laid significantly more eggs than equivalent sized ap. hydrosauri. although the two species are ecologically simi ...19911787031
parasite burdens and host susceptibility of zebu and n'dama cattle in village herds in gambia.helminth and tick burdens of n'dama cattle kept in village herds were compared with parasite burdens in zebu cattle introduced into the same herds. the animals were monitored regularly for tick and helminth burdens, and blood samples were examined for differential white cell counts. the zebu were found to have significantly higher numbers of endo- and ectoparasites. the n'dama had significantly higher levels of circulating eosinophils than the zebu during peak parasite burdens. no difference in ...19911788936
the occurrence of streptothricosis and its association with amblyomma variegatum ticks in st. lucia.cattle, horses, sheep and goats in all areas of st. lucia were examined to ascertain the prevalence and distribution of streptothricosis on the island and to investigate its association with the occurrence of amblyomma variegatum ticks. although the disease was found to occur throughout st. lucia it was more prevalent and generally of a more severe form in areas where a. variegatum ticks are present. a tick control programme in the north of the island appeared to have resulted in a dramatic redu ...19911789020
re-assessment of tick control after immunization against east coast fever in the eastern province of zambia.east coast fever, caused by the protozoon theileria parva and transmitted by the ixodid tick rhipicephalus appendiculatus is one of the most important cattle diseases in east and central africa, responsible for considerable direct losses and necessitating expensive control measures. traditionally, the disease was controlled by means of intensive tick control. the belgian animal disease control project was requested to study the disease epizootiology and vector ecology in order to formulate and i ...19911793284
crimean-congo haemorrhagic fever virus replication in adult hyalomma truncatum and amblyomma variegatum ticks.the kinetics of the replication of the crimean-congo haemorrhagic fever virus (cchfv) was studied in intra-anally inoculated adult hyalomma truncatum and amblyomma variegatum ticks. the virus was re-isolated by suckling mouse inoculation and revealed by antigen capture with ground ticks and indirect immunofluorescence of haemolymph. the virus was detected in ticks in the first hours post-inoculation (p.i.) and its replication was observed from 36 h p.i. onwards. virus titre reached a maximum wit ...19911803413
ticks (ixodidae) parasitizing humans in four provinces of north-western four provinces of north-western argentina (catamarca, jujuy, salta and tucumán), between march 1976 and march 1990, 514 ticks were found on humans. they were identified as rhipicephalus sanguineus group (1 male), boophilus microplus (6 male, 1 female), amblyomma parvum (9 male, 13 female), a. cajannense (35 male, 30 female, 81 nymphs), a. neumanni (33 male, 41 female, 144 nymphs) and amblyomma spp. (10 nymphs, 110 larvae). most of the ticks were from the phytogeographical region of chaco, one ...19911809248
[seasonal dynamics of tick infestations in cattle (ixodoidea) in cattle sold in the area of yaoundé, cameroon].among the tick species identified in cameroon, eight were found in cattle in yaoundé: amblyomma variegatum, boophilus annulatus, b. decoloratus, haemaphysalis aciculifer, hyalomma nitidum, rhipicephalus longus, rh. lunulatus, rh. sulcatus. three species, hm. aciculifer, h. nitidum and rh. lunulatus, were identified for the first time in yaoundé. rhipicephalus and hyalomma were abundant during the rainy season. boophilus was abundant throughout the year, with a maximum concentration at the end of ...19911824137
[sites of fixation of amblyomma variegatum ticks on their hosts in guadeloupe (french west indies)].the examination of 458 domestic and wild hosts of the tick a. variegatum allowed to collect 8,581 larvae, 646 nymphs, 685 adults in 9 different animal species and to determine their preferential attachment sites. in another survey on 15 goats and 5 cattle, 12,345 larvae, 2,111 nymphs and 4,625 adults were counted on the anatomic sites. immature ticks feed preferentially on the head, neck and limbs of birds, the limbs of mongoose and the limbs and ears of dogs, goats and cattle. adults feed only ...19911843828
predation on livestock ticks by chickens.chickens were shown to be natural predators of ticks. rhipicephalus appendiculatus were recovered in large numbers from the crops and gizzards of chickens which had scavenged for 30 min-1 h among tick-infested cattle. other ticks recovered were amblyomma variegatum and boophilus decoloratus. the numbers of ticks recovered ranged from 3 to 331, with an average of 81 per chicken. cattle facilitated the predation of ticks by certain behavioural actions. chickens also picked up both engorged and une ...19911858289
histopathology of attachment sites of amblyomma variegatum and rhipicephalus appendiculatus on zebu cattle of varying resistance to ticks.mature, unimproved east african zebu cattle (bos indicus) naturally exposed to ticks from birth were ranked for resistance to ticks by repeated whole-body counts of infesting ticks. four cattle of high resistance, four of low resistance and two of intermediate resistance were artificially infested with nymphs of amblyomma variegatum and rhipicephalus appendiculatus. two friesian cattle (bos taurus) with less exposure to ticks were similarly infested. biopsies of tick attachment sites were examin ...19911858290
role of genital sex pheromones in amblyomma americanum and a. maculatum (acari: ixodidae).amblyomma americanum and a. maculatum were studied to determine if genital sex pheromones were present, as reported in dermacentor species. chemical analysis of methanol extracts of the anterior reproductive tracts (source of the genital sex pheromone) of a. americanum and a. maculatum confirmed the presence of the same fatty acids that act as components of the genital sex pheromone in dermacentor variabilis and d. andersoni. in both amblyomma species, removal of the anterior reproductive-tract ...19911860418
dissemination, replication, and trans-stadial persistence of dugbe virus (nairovirus, bunyaviridae) in the tick vector amblyomma variegatum.the dissemination and replication of dugbe (dug) virus and its tissue tropisms in the tick vector amblyomma variegatum were examined by immunohistochemical analysis using specific antibody, in situ hybridization with a viral-complementary riboprobe, and infectivity assays of dissected tissues. dugbe virus was localized in both unfed and feeding adults inoculated as nymphs or orally infected by capillary feeding, and in nymphs infected by capillary feeding. in non-feeding ticks, the main sites of ...19911867347
venezuelan equine encephalomyelitis virus infection in and transmission by the tick amblyomma cajennense (arachnida: ixodidae).to assess a possible role of ticks as the maintenance host for epizootic strains of venezuelan equine encephalomyelitis (vee) virus, laboratory experiments were conducted to determine if ticks could become infected, maintain, and transmit the virus. larval and nymphal amblyomma cajennense (f.) and larval dermacentor nitens neumann ticks were exposed to epizootic vee virus (trinidad donkey strain) by allowing them to feed on viremic guinea pigs (strain 13). in a. cajennense, transstadial transmis ...19911875367
effect of ivermectin on the volume of blood ingested by two species of ticks (acari: ixodidae) feeding on cattle.females of the lone star tick, amblyomma americanum (l.), and the american dog tick, dermacentor variabilis (say), were fed on ivermectin (ivomec)-treated and untreated bovines to determine the effect of the acaricide on volume of blood ingested and to compare the weight differences between the treatment and control groups at various time intervals after attachment. adult females from each genus were collected from bos tarus hosts and subjected to hematin assays on three collection dates to esti ...19911875376
a review of the ixodid ticks (acari, ixodidae) occurring in southern africa.eighty-three species of ixodid ticks, as well as several entities that have yet to be described, occur in the republic of south africa plus the 4 independent states lying within its borders (bophuthatswana, venda, transkei and ciskei) and in namibia, botswana, lesotho and swaziland. they belong to the following genera: amblyomma (8 spp.); aponomma (3 spp.); boophilus (2 spp.); cosmiomma (1 sp.); dermacentor (1 sp.); haemaphysalis (10 spp.); hyalomma (2 spp., one of them with 2 subspp.); ixodes ( ...19911881661
resistance of restrained bos taurus dairy bull calves to the bont tick amblyomma hebraeum (acarina: ixodidae).three infestations of restrained jersey and friesland bull calves with adult amblyomma hebraeum did not affect the rate of engorgement of female ticks and resulted in an insignificant decline in the mean engorgement weight of female ticks recovered from the friesland group. repeated infestations significantly affected the egg-laying capacity of engorged female ticks recovered from both groups of hosts. the friesland calves manifested an enhanced resistance to the larvae and nymphs of amblyomma h ...19911882498
specificity and effects of host resistance on the african tick rhipicephalus zambeziensis (acarina: ixodidae).repeated infestations of the rabbit with adult rhipicephalus zambeziensis ticks resulted in a ten-fold reduction in engorgement weight of adult ticks and a significant decline in engorgement weight of nymphs. there was no evidence of cross-resistance against the south african bont tick, amblyomma hebraeum. immunization of rabbits with crude extracts of whole-tick protein significantly influenced engorgement weights and oviposition rates of adult r. zambeziensis. histological studies of tissues f ...19911893799
pheromone/acaricide mixtures in the control of the tick amblyomma hebraeum: effects of acaricides on attraction and attachment.unfed adults and nymphs of the bont tick amblyomma hebraeum koch are attracted to hosts on which fed males, emitting an aggregation-attachment pheromone (aap), are attached. pheromone/acaricide mixtures have the potential to selectively attract and kill these ticks. we have investigated the effects of three acaricides, amitraz (an amidine), flumethrin (a synthetic pyrethroid) and chlorfenvinphos (an organophosphate), combined with aap, on the attraction and attachment of the unfed adults. attrac ...19911893800
comparative studies on the vector capacity of the different stages of amblyomma variegatum fabricius and hyalomma rufipes koch for congo virus, after intracoelomic inoculation.groups of nymphs and adults of hyalomma rufipes and larvae, nymphs and adults of amblyomma variegatum were infected by intracoelomic inoculation with congo virus at concentrations of 10(3.5)ld50 (group a), 10(1.5)ld50 (group b) and 10(0.5)ld50 (group c). the infection rates for the different groups were: groups a, 92-100% for all stages of ticks, except for adult h. rufipes which had 87%; group b, 56.8, 68.1 and 50.7% for larvae, nymphs and adults of a. variegatum, respectively, and 96.3 and 84. ...19911907050
acquisition of resistance to the bont tick amblyomma hebraeum (acarina: ixodidae) by goats.goats acquired resistance to larvae of amblyomma hebraeum following three repeated infestations. resistance was associated with immediate type i hypersensitivity reactions following intradermal skin tests using crude egg extracts. in a separate experiment, the inoculation of tick-naive goats with extracts of the larvae of a. hebraeum failed to induce observable effects on feeding larvae despite the development of anti-larval antibodies.19911909066
studies on ticks of veterinary importance in nigeria: intrinsic factors influencing oviposition and egg-hatch of amblyomma variegatum under natural conditions.during the peak of rains of 1983, 1984 and 1985 in the forest zone of nigeria, female amblyomma variegatum engorged to various weights were subjected to different experiments for the purpose of observing the intrinsic factors which influence oviposition and egg-hatch under natural conditions. two types of oviposition patterns were observed. new terms were introduced to quantify the relationships between the daily weight loss and daily number of eggs oviposited by a tick. these terms are "actual ...19911916533
manifestations of immunity in sheep repeatedly infested with amblyomma americanum ticks.three sheep were infested 4 times with 100 amblyomma americanum tick pairs and kept indoors until the natural termination of the infestations. characteristics of the tick populations that show efficiency of feeding, fertility, and offspring development, and elisa antibodies to tick salivary gland extracts were studied at each infestation. on average, female ticks fed on tick-naive sheep detached at 12.1 +/- 0.2 (mean +/- standard error) days, weighed 492 +/- 16.8 mg, engorged 40.7 mg per day, an ...19911919917
antigens of amblyomma americanum ticks recognized by repeatedly infested sheep.sera were taken from 3 sheep that had been infested 5 times with amblyomma americanum and that exhibited manifestations of humoral depression to homologous antigens and anti-tick resistance. proteins extracted from the intestine or salivary glands of unfed ticks or salivary glands from partially (3-day) fed ticks were analyzed by polyacrylamide gel electrophoresis (page) and sodium dodecyl sulfate-page. antigens recognized by the sheep in the same materials before and after each infestation were ...19911919918
parasites of domestic and wild animals in south africa. xxv. ixodid ticks on sheep in the north-eastern orange free state and in the eastern cape province.the tick burdens of 115 merino sheep, slaughtered over a period of 15 consecutive months on a farm in the north-eastern orange free state, were determined. a total of 7 ixodid and 1 argasid tick species were recovered and the seasonal abundances of boophilus decoloratus, hyalomma marginatum rufipes, margaropus winthemi and rhipicephalus evertsi evertsi were determined. one hundred and forty-nine merino sheep were slaughtered over periods varying from 10 to 25 months on 3 farms in eastern provinc ...19911923373
parasites of domestic and wild animals in south africa. xxvii. ticks on helmeted guineafowls in the eastern cape province and eastern transvaal lowveld.seventy-six helmeted guineafowls (numida meleagris) were shot in the andries vosloo kudu reserve and on an adjacent farm in the eastern cape province during the period may 1985 to january 1987 and their tick burdens determined. a total of 10 ixodid tick species were recovered, of which amblyomma hebraeum, amblyomma marmoreum and haemaphysalis silacea were the most abundant. the seasonal abundances of these 3 species and of hyalomma marginatum rufipes were ascertained. a marked difference between ...19911923375
ultrastructural morphology of cowdria ruminantium in midgut epithelial cells of adult amblyomma hebraeum female ticks.amblyomma hebraeum male and female ticks, experimentally infected as larvae with the ball 3 stock of cowdria ruminantium, were fed on a heartwater susceptible sheep. the initial attachment of the males was required as a pre-requisite for female attachment. reticulate bodies were the predominant morphologic form of cowdria observed in gut epithelial cells after 1-3 days of feeding. single intermediate bodies and no elementary bodies were observed. organisms were found within a membrane-bound vacu ...19911923381
distribution and incidence of ectoparasites on small mammals in a rainforest belt of southern nigeria.a total of 174 small mammalian hosts were trapped in ekpoma, bendel state, nigeria from october, 1986 to september, 1987 and examined for ectoparasites. 108 infested hosts had 10 species of ectoparasites comprising three species of mites (laelaps (echinolaelaps) muricola, laelaps (e.) gigantea and laelaps (e.) echidninus); two species of ticks (amblyomma variegatum and ixodes sp.); two species of fleas (xenopsylla cheopis and x. braziliensis); and on especies each of sucking lice (polyplax spinu ...19911928798
selective breeding for photoperiodically induced developmental diapause in laboratory strains of amblyomma americanum (acari: ixodidae).offspring of amblyomma americanum (l.) reared for four generations in a 12:12 (l:d) photoperiod in the laboratory were held in 10:14 (l:d) conditions and bred to select for developmental diapause (dia) or nondiapause (non) characteristics for two additional generations. sequential generations of fed dia nymphs had mean molting times (days from detachment to ecdysis) that were 8.0% (dia1) and 35.7% (dia2) greater than parental ticks, and maximal development time was extended by 20% in dia2 ticks ...19911941917
mechanisms of host-tick contact with special reference to amblyomma americanum (acari: ixodidae) in beef cattle forage least five groups of parameters regulate contact between ticks and host animals. group 1 (seasonal effects) and group 2 (daily effects) comprise abiotic parameters and include daylength, temperature, relative humidity, and interactions thereof. groups 3, 4, and 5 consist of biotic parameters. these pertain to biological processes in ticks (group 3), such as hunger responses and spatial patterns in aphagous tick populations; biological processes in host animals (group 4), such as patterns of h ...19911941920
transmission of a spotted fever group rickettsia by amblyomma hebraeum (acari: ixodidae).amblyomma hebraeum, a cattle tick common in southern africa, was demonstrated to be capable of maintaining an infection with an unclassified spotted fever group rickettsia both transtadially and transovarially. all feeding stages of the tick transmitted the infection to rabbits. the rickettsia was isolated and found to be serotypically distinct from three strains of rickettsia conorii by microimmunofluorescence. rabbit serum titers were found to be higher with indirect fluorescent antibody (ifa) ...19911941925
tick (acari: ixodidae) infestations on zebu cattle in western kenya: seasonal dynamics of four species of ticks on traditionally managed cattle.a study was conducted on the population dynamics of four tick species infesting livestock on rusinga island. infestations of rhipicephalus appendiculatus neumann, rhipicephalus evertsi evertsi neumann, amblyomma variegatum (f.)., and boophilus decoloratus (koch) were monitored on east african shorthorn zebu cattle at monthly intervals for 2 yr. these cattle were of unimproved stock under traditional husbandry without any tick control practices. most ticks were on cattle between september and mar ...19911941930
etiologic agent of lyme disease, borrelia burgdorferi, detected in ticks (acari: ixodidae) collected at a focus in alabama.the study was conducted at sites of known transmission of borrelia burgdorferi in east central alabama. the objectives were to determine species of ticks present at these sites, their host associations, and species of ticks and small mammals naturally infected with b. burgdorferi. a total of 451 hosts were examined for ticks, including cotton mice, peromyscus gossypinus (le conte); cotton rats, sigmodon hispidus say & ord; southern short-tailed shrews, blarina carolinensis (bachman); house mice, ...19911941933
borrelia burgdorferi in ticks (acari: ixodidae) from coastal virginia.ixodid ticks removed from hosts and from vegetation during march-november 1987 at sites in coastal virginia and north carolina were examined for borrelia burgdorferi. b. burgdorferi was evident in nine (22%) ixodes cookei packard removed from rice rats (oryzomys palustris), a white-footed mouse (peromyscus leucopus), and raccoons (procyon lotor); four (6%) amblyomma americanum (l.) removed from raccoons; and two (3%) dermacentor variabilis (say) removed from a raccoon and a rice rat. b. burgdorf ...19911941936
horizontal movement of adult ixodes dammini (acari: ixodidae) attracted to co2-baited traps.the ability of male and female deer ticks, ixodes dammini spielman, clifford, piesman, & corwin, to move horizontally was evaluated by performing a mark-recapture study. in each of two experiments, 120 ticks were marked with fluorescent powder and released at predetermined distances from a co2-baited trap. the mean recruitment distance was 1.8 m after 6 d of trap operation. this distance is appreciably lower than those calculated from previous studies of several other species of ixodid ticks, in ...19911941943
isolation of spotted fever group rickettsias from triturated ticks using a modification of the centrifugation-shell vial technique.a modification of the centrifugation-shell vial technique was used to isolate spotted fever group (sfg) rickettsias from triturated ticks which had previously been stored at -80 degrees c for up to 7 months. sfg rickettsias were successfully isolated in vero cells from all 7 haemolymph positive ticks (amblyomma hebraeum) used in the experiment. attempts were also made to use these tick triturates to establish sfg rickettsial infections in tissue culture. vero cells were used for 5 of the tick tr ...19911949146
ehrlichiosis in children.tick-borne rickettsiae of the genus ehrlichia have recently been recognized as a cause of human illness in the united states. in the years 1986-1988, 10 cases of ehrlichiosis were diagnosed in children in oklahoma. fever and headache were universal: myalgias, nausea, vomiting, and anorexia were also common. rash was observed in six patients but was a prominent finding in only one. leukopenia, lymphopenia, and thrombocytopenia were common laboratory abnormalities. six patients were treated with t ...19911987531
role of cattle in the epidemiology of tick-bite fever in zimbabwe.almost 100% of 52 cattle tested from the southern areas of zimbabwe were found to have antibodies reactive with rickettsia conorii compared with less than 30% of 120 cattle from the north. steers artificially infected with r. conorii isolated from amblyomma hebraeum were found to show no hematological or biochemical signs of disease but did seroconvert. clinical signs of infection were restricted to regional lymphadenopathy and dermal erythema, edema, and tenderness at the inoculation site. rick ...19912007631
tick information sheet. the lone star tick. amblyomma americanum. 19912014616
ixodid and argasid ticks. keys to their identification.ticks of the ixodidae family are important ectoparasites of humans and animals. of the 80 or so species found in the united states, about 20 are of veterinary importance. ticks are second only to mosquitoes as carriers of human pathogens. the ixodid (or hard) ticks are the most common and are represented by the genera ixodes, haemaphysalis, boophilus, rhipicephalus, amblyomma, and dermacentor. accurate identification of the species of ixodid ticks within an area is a prerequisite to control and ...19912014622
exotic ectoparasites of ostriches recently imported into the united states.eleven species of ectoparasitic arthropods were collected and identified from ostriches (struthio camelus) recently imported into the united states from africa and europe. four of these species are reported from ostriches for the first time. the parasites included adult hippoboscid flies (struthiobosca struthionis) and 10 species of adult ixodid ticks (amblyomma gemma, a. lepidum, a. variegatum, haemaphysalis punctata, hyalomma albiparmatum, h. luscitanicum, h. marginatum rufipes, h. truncatum, ...19912023323
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
amblyomma americanum: characterization of salivary prostaglandins e2 and f2 alpha by rp-hplc/bioassay and gas chromatography-mass spectrometry.secretagogue-induced saliva of the tick, amblyomma americanum (l.) was fractionated by reversed-phase-high-performance liquid chromatography (rp-hplc) and bioassayed in smooth muscle preparations. material with retention times of authentic prostaglandin e2 (pge2) and prostaglandin f2 alpha (pgf2 alpha) were found to cause contraction of preparations of rat colon and rat stomach strips. gas chromatography-mass spectra of selected ions of both hplc-purified fractions confirmed the existence of pge ...19921730268
responses of the ticks amblyomma hebraeum and a. variegatum to known or potential components of the aggregation-attachment pheromone. iii. aggregation.ten known or potential components of the aggregation-attachment pheromone (aap) of the ticks amblyomma hebraeum and a. variegatum, as well as mixtures of these components, extracts of prefed males and live prefed males, were tested as aggregation stimulants. in field assays, laboratory-reared unfed male and female ticks were released 20 cm downwind of co2/pheromone release sites; the numbers of ticks that aggregated at the release sites were recorded after 30 min. in a. variegatum, aggregation w ...19921286609
responses of the ticks amblyomma hebraeum and a. variegatum to known or potential components of the aggregation-attachment pheromone. iv. attachment stimulation of nymphs.ten known or potential components of the aggregation-attachment pheromone (aap) of the ticks amblyomma hebraeum and a. variegatum, as well as a mixture of these components and extracts of prefed males of the two species, were tested as attachment stimulants for nymphs. unfed nymphs were confined in linen bags on the ears of rabbits that had been treated with the test compounds, mixture or extracts; the numbers attached were recorded after 24 h. in a. hebraeum, attachment was induced by four comp ...19921286610
parasites of domestic and wild animals in south africa. xxx. ectoparasites of kudus in the eastern transvaal lowveld and the eastern cape province.sets of four kudus were shot and examined for arthropod parasites at approximately monthly intervals from april 1981 to march 1983 in the southern part of the kruger national park, eastern transvaal lowveld. these animals harboured 10 ixodid tick species of which boophilus decoloratus followed by amblyomma hebraeum were the most abundant. the seasonal abundances of these ticks and of amblyomma marmoreum, rhipicephalus appendiculatus, rhipicephalus evertsi evertsi and rhipicephalus zambeziensis w ...19921297956
[attempt to attract amblyomma variegatum (acarina:ixodina) on cattle previously treated with aggregation-fixation pheromones and a pyrethrinoid acaricide].the application of synthetic pheromonal aggregation-attachment compounds or male tick extracts on certain sites of the body of bull calves reared on infested pastures did not induce any attraction of free adults on these sites. previously attached males were more attractive than synthetic pheromones or natural extracts. very small amounts of flumethrin poured directly on testicles or on the dewalp induced a large decrease in the infestation of these sites.19921298024
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