TitleAbstractYear(sorted ascending)
[asymptomatic carrier state in creole goats and cattle after recovery from cowdria infection in guadeloupe].creole goats and cattle in guadeloupe can be carriers of cowdriosis (heartwater: cowdria ruminantium) after recovery for a period as long as 11 months in goats and 2 months in cattle. the carrier status was demonstrated by feeding amblyomma variegatum nymphs on recovered animals and the resulting adult ticks on susceptible goats. cowdria ruminantium was not detected permanently during the carrier status.19921301623
saliva-activated transmission (sat) of thogoto virus: dynamics of sat factor activity in the salivary glands of rhipicephalus appendiculatus, amblyomma variegatum, and boophilus microplus ticks.thogoto (tho) 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. this form of non-viraemic transmission is potentiated by a factor(s) secreted by the saliva of ticks and hence has been termed saliva-activated transmission (sat). the synthesis of the sat factor by the salivary glands of three ixodid tick species was determined by placing uninfected nymphal ticks on guinea-pigs that wer ...19921326431
perception of breath components by the tropical bont tick, amblyomma variegatum fabricius (ixodidae). i. co2-excited and co2-inhibited receptors.wall-pore olfactory sensilla located in the capsule of haller's organ on the tarsus of amblyomma variegatum ticks bear cells responding to vertebrate breath: one of these sensilla contains a co2-excited receptor and a second sensillum has a co2-inhibited receptor. each of these antagonistic co2-receptors, which display typical phasic-tonic responses, monitors a different co2-concentration range. the co2-inhibited receptor is very sensitive to small concentration changes between 0 and ca. 0.2%, b ...19921331433
comparative study of tick burdens in gudali and wakwa cattle under natural infestation in the subhumid highlands of wakwa, cameroon. preliminary observations.the relative resistance to different cattle ticks of gudali and wakwa cattle with different levels of brahman breeding, grazed on natural pastures in the subhumid tropics of wakwa, cameroon, was assessed using pasture tick infestations. the basic design consisted of 5 young bulls of each breed from different sire herds. tick populations were observed in gudali and wakwa bulls over a period of four weeks when the climate was thought to be highly favourable for the free-living stages of ticks. cou ...19921339999
experimental transmission of cowdria ruminantium (rickettsiales) by the american reptile tick amblyomma dissimile koch, 1844.a senegalese isolate of the rickettsia cowdria ruminantium was transmitted transstadially by nymphs of the american reptile tick amblyomma dissimile. only eight nymphs, fed as larvae on a saanen goat reacting to heartwater, were required to transmit fatal heartwater to another susceptible goat. since a. dissimile usually feeds on snakes, iguanas and lizards in central america, the tick is not considered to play a significant role in the transmission of heartwater between ruminants. however, the ...19921395974
laboratory studies on the life cycle of amblyomma marmoreum (acari: ixodidae) on two different hosts.a comparative study was made of the life cycle of the tortoise tick, amblyomma marmoreum koch, on tortoises and guinea pigs under laboratory conditions. at 25 degrees c and 85% rh with natural day length, duration of off-host stages (preoviposition, oviposition, incubation, and premolt) was similar for ticks fed on both hosts. delay in preoviposition (up to 90 d) was observed in some gravid females. larvae, nymphs, and adults had longer feeding periods on tortoises than on guinea pigs. adult fem ...19921404252
immunization of rabbits against nymphs of amblyomma hebraeum and a. marmoreum (acari: ixodidae).himalayan rabbits immunized with homogenates prepared from nymphs of amblyomma hebraeum koch and a. marmoreum koch ticks developed humoral and probably also cell-mediated immunity to their respective homogenates. beta and gamma globulin levels and numbers of eosinophils and neutrophils increased significantly in inoculated rabbits. the recipient animals developed resistance to homospecific nymphal infestations. cross resistance between the two species was not evaluated. nymphs of both species th ...19921404253
comparative infections of epizootic and enzootic strains of venezuelan equine encephalomyelitis virus in amblyomma cajennense (acari: ixodidae).to compare the potential for an enzootic or an epizootic strain of venezuelan equine encephalomyelitis (vee) virus to infect amblyomma cajennense (f.), larval ticks were fed on guinea pigs (strain 13) inoculated with an enzootic viral strain of variant i-e (68u201) or on guinea pigs inoculated with an epizootic strain of variant i-a (trinidad donkey). peak viremias were 10(5.2) plaque-forming units (pfu)/ml and 10(7.3) pfu/ml in guinea pigs infected with enzootic and epizootic viral strains, res ...19921404262
influence of exposure period and management methods on the effectiveness of chickens as predators of ticks infesting cattle.experiments undertaken on rusinga island, kenya, indicated that rhipicephalus appendiculatus (neumann) was the predominant tick consumed on tick-infested cattle by chickens, followed by amblyomma variegatum (fabricius), boophilus decoloratus (koch) and rhipicephalus evertsi evertsi (neumann). the number of ticks consumed by chickens released with cattle in a 3 h release period was not significantly different from ticks consumed in a 4 h release period. in a free management system, chickens 1-3 m ...19921413461
acquired immunity to larvae of amblyomma marmoreum and a.hebraeum by tortoises, guinea-pigs and guinea-fowl.a study of acquired resistance in guinea-pigs, guinea-fowl and tortoises to larvae of the ticks amblyomma hebraeum koch and a.marmoreum koch (acari: ixodidae) showed that repeated infestations of the laboratory host resulted in a 29.3-49.4% reduction respectively in weight of engorged larvae. no resistance was induced in guinea-fowl, the natural host for larvae of both species. a small decline in the mean weight of engorged larvae was observed for both species of ticks after three successive inf ...19921421505
perception of breath components by the tropical bont tick, amblyomma variegatum fabricius (ixodidae). ii. sulfide-receptors.wall-pore sensilla in the capsule of haller's organ on foreleg tarsi of the tick, amblyomma variegatum, show multicellular responses upon stimulation with human and bovine breath. filtering breath through charcoal removes the stimulant for some of these receptors. analysis by gas chromatography coupled with olfactory sensillum electrophysiological recordings indicates that an ethanol extract of the breath components trapped on charcoal contains a major stimulant eluting at the same retention tim ...19921432848
an indirect mechanism by which a protein from the male gonad hastens salivary gland degeneration in the female ixodid tick, amblyomma the adult female tick, amblyomma hebraeum koch (acari: ixodidae), salivary gland degeneration is triggered by an ecdysteroid, provided the female is above a critical weight (approximately 300-400 mg). in mated females, salivary gland degeneration is virtually complete within 4 days of detachment from the host. in virgin females, salivary gland degeneration is delayed by 4 days. this delay can be reversed by the injection of a male reproductive tract homogenate directly into the hemocoel. in t ...19921446071
comparison of the attachment rates of males of the ticks amblyomma hebraeum and a. variegatum to cattle, sheep and rabbits in the absence of aggregation-attachment pheromone.losses in domestic ruminants caused by heartwater (cowdria ruminantium infection) in zimbabwe and mozambique are greater when the vector is amblyomma hebraeum than when the vector is a. variegatum. it has been suggested that the epidemiology of the disease may be influenced by the rates at which unfed adults of these two tick species attach to uninfested hosts (i.e. in the absence of the male-produced aggregation-attachment pheromone [aap]). in this study we confined unfed males of a. hebraeum a ...19921446569
the identification of a shared immunogen present in the salivary glands and gut of ixodid and argasid ticks.the identification of a 70-kda immunogen present in salivary gland extracts of several ixodid species, namely hyalomma truncatum (sweating-sickness-inducing (ss+) and non-inducing (ss-) strains), hyalomma marginatum rufipes and rhipicephalus evertsi evertsi, is reported. the immunogen was identified by western blots using a monoclonal antibody of the igm isotype directed against a 70-kda immunogen present in the salivary glands of (ss-) female h. truncatum ticks. cross-reactivity with the gut of ...19921446571
synganglial morphology and neurosecretory centers of adult amblyomma americanum (l.) (acari: ixodidae).lone star ticks, amblyomma americanum (l.), were processed by standard histological means for paraffin embedding, sectioning, and staining by the paraldehyde-fuchsin technique. the synganglion is highly condensed around the esophagus and possesses paired optic, cheliceral, palpal, pedal i-iv nerves, and opisthosomal nerves and a single unpaired esophageal nerve. although optic nerves were observed leading from the eyes to the protocerebrum, distinct optic ganglia were not seen in any of the prep ...19921460618
parasites of cottontail rabbits of southern illinois.fifteen species of parasites including haemaphysalis leporispalustris, ixodes dentatus, amblyomma americanum, cediopsylla simplex, odontopsyllus multispinosus, cuterebra sp., obeliscoides cuniculi, trichostrongylus calcaratus, trichostrongylus affinis, longistriata noviberiae, dermatoxys veligera, trichuris sp., mosgovoyia sp., taenia pisiformis, and hasstilesia tricolor as well as coccidia oocysts were collected from 96 cottontail rabbits (sylvilagus floridanus) confined to a pen in southern il ...19921491303
tick (acari: ixodidae) attachment cement and salivary gland cells contain similar immunoreactive polypeptides.a specific antiserum (12c) raised to a 90-kda immunogenic component of salivary glands of the tick rhipicephalus appendiculatus recognized similar 90-kda polypeptides from salivary glands of the american dog tick, dermacentor variabilis, and the lone star tick, amblyomma americanum, as well as 70-kda polypeptides in the cement of d. variabilis, a. americanum, and r. sanguineus (brown dog tick). the reduction in size of the polypeptide for these ticks suggests that it is modified in some way duri ...19921495047
feeding efficiency of larval hyalomma truncatum (acari: ixodidae) on hosts previously exposed to ticks.the effect of guinea pig response to feeding larval hyalomma truncatum koch ticks was studied by measuring the percentage of ticks engorging and molting, their engorged weight, and hemoglobin content. four guinea pigs were infested with 100, 200, 400, and 1,000 larvae, respectively, on three occasions at 21-d intervals, followed by a fourth infestation with 500 larvae. during the second, third, and fourth infestations, significantly fewer ticks engorged on each guinea pig than during the first i ...19921495048
tick sweep: modification of the tick drag-flag method for sampling nymphs of the deer tick (acari: ixodidae).we describe a version of the standard tick drag-flag modified for use in close-growing and tangled vegetation, as well as under ornamental shrubbery and fallen branches. two major features of the sweep are: (1) it allows the user to remain upright with the flag parallel to the ground, thus sampling effectively beneath low and fallen branches and around shrubs, as well as capturing host-seeking ticks in advance of the operator; and (2) the use of a flannel rubberized-laminate fabric (crib sheet) ...19921495058
field evaluation of two formulations of cyfluthrin for control of ixodes dammini and amblyomma americanum (acari: ixodidae).liquid or granular cyfluthrin was applied in the spring and fall to different test plots at a rate of 0.41 (ai) kg/ha to control ixodes dammini spielman, clifford, piesman & corwin and amblyomma americanum (l.). spring application of liquid cyfluthrin showed the most significant decreases of both species. i. dammini nymphs were reduced 97% at 10 d, 100% at 2 mo, and 100% at 1 yr; and a. americanum adults and nymphs were reduced 91-93% at 10 d and 100% at 2 mo posttreatment. granular cyfluthrin a ...19921495073
attempted transmission of borrelia burgdorferi (spirochaetales: spirochaetaceae) (jdi strain) by ixodes scapularis (acari: ixodidae), dermacentor variabilis, and amblyomma americanum.laboratory-reared ixodes scapularis say, amblyomma americanum (l.), and dermacentor variabilis (say) were fed on new zealand white rabbits experimentally infected with borrelia burgdorferi (jdi strain). at repletion, spirochetes could be detected by dark-field microscopy only in i. scapularis. acquisition rates were 18 and 21%. when previously exposed nymphs of each species were fed on susceptible rabbits, i. scapularis was the only tick of the three species that transmitted b. burgdorferi. when ...19921495078
ultrastructure of symbiont-like microorganisms associated with the sperm of ixodid ticks.the endospermatophores found in the seminal receptacles of three species of ixodid ticks: hyalomma marginatum, h. dromedarii and amblyomma hebraeum were examined. the seminal receptacles showed the presence of symbiont-like microorganisms in association with the sperm cells. these yeast-like microorganisms represent extracellular symbionts, produced by the male and introduced in the genital system of the female through copulation. the symbionts frequently occur freely in large agglomerations sur ...19921500765
a freeze etching study on the distribution of nuclear pores during spermatogenesis in this study the freeze-fracturing and freeze-etching techniques was used to study pore distribution during spermatogenesis in ticks. three species of ixodid ticks were studied: hyalomma dromedarii, h. marginatum and amblyomma hebraeum. in all three species of the ticks examined, the nuclei of the early stages of male germ cells showed varying degrees of aggregation into pore-rich and pore-poor areas. spermatocytes demonstrated significant pore clustering in pore-rich areas, leaving areas almos ...19921500776
a contribution to the anatomy and histology of the female reproductive system of amblyomma cajennense (acarina: ixodidae).the genital system of the tick amblyomma cajennense is composed of several parts: a single tubular ovary where a great number of ova develop except for a longitudinal groove on its dorsal surface, with feeding the ova develop multiplying the size and weight of the ovary, as they reach maturity they are ovulated into the lumen. two oviducts are connected to the ovary on each side, these thicken at a certain region forming the knee shaped ampulla. this significant region is where great numbers of ...19921500779
borrelia sp. in ticks recovered from white-tailed deer in alabama.six hundred sixty-five hunter-killed white-tailed deer (odocoileus virginianus) from 18 counties in alabama (usa) were examined for ticks. most of the collections were made at state-operated wildlife management areas. four species of ticks (n = 4,527) were recovered: the lone star tick amblyomma americanum (n = 482); the gulf coast tick a. maculatum (n = 11); the winter tick dermacentor albipictus (n = 1,242); and the black-legged tick ixodes scapularis (n = 2,792). fifty-six percent of the tick ...19921512879
monthly incidence of theileria cervi and seroconversion to babesia odocoilei in white-tailed deer (odocoileus virginianus) in texas.monthly monitoring of fawns collected from an area in texas endemic for theileria cervi and babesia odocoilei showed that transmission of t. cervi occurred during july and august, a time period consistent with the occurrence of amblyomma americanum. seroconversion to b. odocoilei occurred during october to december and possibly continued through january and february. the time of seroconversion was more suggestive of transmission of b. odocoilei by ixodes scapularis than by amblyomma americanum.19921512881
ectoparasites of the blackbuck antelope (antilope cervicapra).fifty-two free-ranging blackbuck antelope (antilope cervicapra) from texas were examined for ectoparasites. two species of sucking lice (anoplura), one species of chewing louse (mallophaga), one species of louse fly (diptera), and three species of ticks (acari) were found. this is the first report of the anoplurans linognathus cervicaprae and l. pithodes from the western hemisphere. the southern deer ked (lipoptena mazamae), the winter tick (dermacentor albipictus), and the rabbit tick (haemaphy ...19921512888
adult amblyomma hebraeum burdens and heartwater endemic stability in cattle.several conclusions of importance to studies on the epidemiology of heartwater were drawn from an investigation in which the numbers of adult amblyomma hebraeum ticks, to which a closed herd of hereford cattle were exposed over a period of 6 1/2 years, were manipulated. with a tick cowdria ruminantium infection rate of 3-5%, an endemically stable situation was created by dipping the herd only when an average of 10 adult male and female a. hebraeum ticks were counted on 10 animals. when the avera ...19921513597
description of aegyptianella botuliformis n. sp. (rickettsiales: anaplasmataceae) from the helmeted guineafowl, numida meleagris.aegyptianella botuliformis n. sp. (rickettsiales: anaplasmataceae) isolated from helmeted guineafowls numida meleagris from the kruger national park is described. the rickettsia occurs within a membrane-bound vacuole in the cytoplasm of erythrocytes with up to 8 organisms in a mature inclusion. the initial body resembles that of aegyptianella pullorum. the tightly packed, sausage-shaped intermediate forms are a distinctive morphological feature, seen as irregular, pleomorphic forms under light m ...19921513599
effects of the avermectin analogue mk-243 on vitellogenesis and reproduction in the ixodid tick, amblyomma hebraeum.a dose-dependent reduction in weight of total egg mass and a slightly increased oviposition latency were observed following injection of the avermectin analogue mk-243 (4"-epi-methylamino-4"-deoxyavermectin b1) directly into the haemocoel of engorged female amblyomma hebraeum koch (acari: ixodidae). egg laying was almost completely inhibited at 100 micrograms/kg body weight. mk-243 markedly inhibited ovary development and vitellogenesis. ticks treated with 100 micrograms mk-243/kg also had one-t ...19921526201
the use of time-series analysis to forecast bont tick (amblyomma hebraeum) infestations in zimbabwe.studying the dynamics of tick infestations on cattle is an essential step in developing optimal strategies for tick control. successful strategic tick control requires accurate predictions of when tick infestations will reach predetermined threshold levels. in the case of amblyomma hebraeum, earlier work has shown that there is no consistent pattern of seasonal activity. this means that a statistical model for predicting a. hebraeum infestations cannot reliably use climatic factors as the only i ...19921526202
olfactory responses of adult amblyomma hebraeum and a. variegatum (acari: ixodidae) to attractant chemicals in laboratory tests.unfed adults of the african ticks, amblyomma hebraeum koch and a. variegatum (fabricius), important vectors of human and animal diseases, were exposed to volatile compounds in an olfactometer in efforts to identify both tick-produced or synthetic chemicals capable of eliciting an attraction response. a formula, relative efficacy of attraction, was devised for comparison of responses between species and sexes to a particular test stimulus, or within a homogeneous population to different stimuli. ...19921526203
a case of gynandromorphism in amblyomma hebraeum (acari: ixodidae).a gynandromorph specimen of amblyomma hebraeum was found on a goat on which adult ticks were bred in the laboratory.19921552517
oral secretion elicited by effectors of signal transduction pathways in the salivary glands of amblyomma americanum (acari: ixodidae).the abilities of various effectors of signal pathways in tick salivary glands to stimulate oral secretions in partially fed amblyomma americanum (l.) female ticks were compared. pilocarpine stimulated secretion the most rapidly following tick stimulation, but its effectiveness declined with time and subsequent injections. secretion rates induced by dopamine and theophylline increased with time of collection and additional injections and were as effective as pilocarpine after 60 min. activators o ...19921552527
distribution, density, and lyme disease spirochete infection in ixodes dammini (acari: ixodidae) on white-tailed deer in maryland.a statewide survey of ticks parasitizing white-tailed deer was carried out in maryland during november 1989 to assess the status of the deer tick, ixodes dammini spielman, clifford, piesman & corwin, the major vector of lyme disease in the northeastern united states. ticks were collected from deer carcasses brought in by hunters at 23 check stations (one per county). a total of 3,437 i. dammini were collected from 538 of 1,281 deer (42%), together with 2,013 dermacentor albipictus (packard) and ...19921552529
a comparison of the attraction of nymphs and adults of the ticks amblyomma hebraeum and a. variegatum to carbon dioxide and the male-produced aggregation-attachment pheromone.the attraction of nymphs of the ticks amblyomma hebraeum and a. variegatum to co2 alone and co2 together with the male-produced aggregation-attachment pheromone (aap) was investigated. matching experiments on the attraction of the adults of the two species were run for comparison. nymphs of a. hebraeum were strongly attracted to sources of co2 and co2/aap at distances of 10 and 15 m. at distances of 20 and 25 m significantly more nymphs were attracted to co2/aap than to co2 alone. adults of a. h ...19921563302
amblyomma americanum (l.): protein kinase c-independent fluid secretion by isolated salivary glands.protein kinase c activity was partially purified from tick salivary glands by fast protein liquid chromatography anion-exchange chromatography. enzyme activity was stimulated by ca2+, phosphatidylserine, and diacylglycerol with the highest activity observed in the presence of all three modulators. enzyme activity was inhibited by a synthetic pseudosubstrate peptide with an amino acid sequence resembling the protein kinase c substrate phosphorylation site. the protein kinase c activator, 1-oleoyl ...19921582485
interspecific differences in the movements of female ticks on reptiles.movements of females of two reptile ticks, amblyomma limbatum and aponomma hydrosauri were studied to determine whether the behaviour of the species on hosts was similar or different. experiments were conducted to determine if the movement of females on hosts prior to mating was influenced by the delayed attachment of conspecific males. a field experiment was also undertaken to determine whether data obtained during laboratory experiments reflected the behaviour of females on hosts in the field. ...19921587690
laboratory and field observations on anti-tick properties of the plant gynandropsis gynandra (l.) brig.a shrubby plant, abundant in east kenya, gynandropsis gynandra (l.) brig., was shown to exhibit repellent and acaricidal properties to larvae, nymphs and adult rhipicephalus appendiculatus and amblyomma variegatum ticks. all stages of ticks avoided the leaves of the plant and a high percentage of the ticks which were continuously exposed to its leaves died; surviving ticks were weak and inactive but regained activity when exposed to fresh air. the effectiveness of the plant's leaves as a repelle ...19921615623
quantitative evaluation of sampling methods for ixodes dammini and amblyomma americanum (acari: ixodidae).three tick-sampling methods (dry ice-baited tick traps, cloth drags, and ambulatory human host) were evaluated to determine which technique yielded the greatest capture of host-seeking stages of ixodes dammini spielman, clifford, piesman & corwin and amblyomma americanum (l.). the most reliable method, catching more stages and significantly more numbers of i. dammini and a. americanum; was dry ice-baited tick traps. there were no significant differences between the drag and human-host methods fo ...19921625293
inability of ixodes cookei and amblyomma americanum nymphs (acari: ixodidae) to transmit borrelia burgdorferi.the vector competency of ixodes cookei packard and amblyomma americanum (l.) for borrelia burgdorferi was studied using syrian hamsters. ixodes dammini spielman, clifford, piesman & corwin were used as controls. darkfield and immunofluorescent examinations of midgut diverticula revealed b. burgdorferi spirochetes in 32 of 36 (88.9%) i. dammini larvae, 5 of 36 (13.9%) i. cookei larvae, and 7 of 36 (19.4%) a. americanum larvae within 48 h after feeding on infected syrian hamsters. b. burgdorferi w ...19921625302
the role of amblyomma variegatum in the transmission of heartwater with special reference to guadeloupe.heartwater has been diagnosed in guadeloupe, marie-galante, and antigua; it induces important losses among goats and european or cross-bred cattle when local zebu creole are highly resistant to infection. amblyomma variegatum is the vector of the disease in the caribbean. the tick strain of martinique, occurring in that island that has apparently been disease-free since 1948, has not lost its ability to experimentally transmit the disease. in guadeloupe 97% of nymphs and nearly 100% of adults fe ...19921626882
correlation between antibodies to cowdria ruminantium (rickettsiales) in cattle and the distribution of amblyomma vector ticks in zimbabwe.cowdriosis, caused by cowdria ruminantium, is transmitted by amblyomma ticks, which are widely distributed in zimbabwe. to assess the distribution of this disease in zimbabwe, cattle either exposed to amblyomma ticks or maintained in areas free from these ticks were tested for antibodies to cowdria. a total of 324 sera were tested using competitive elisa and the indirect fluorescent antibody test (ifat). at diptanks in amblyomma-infested areas 52% (n = 95) and 26% (n = 47) of sera were positive ...19937628226
pathogenicity of 17 isolates of entomophagous nematodes (steinernematidae and heterorhabditidae) for the ticks amblyomma variegatum (fabricius), boophilus microplus (canestrini) and boophilus annulatus (say).entomopathogenous nematodes are well known biocontrol agents of insects. they live in the superficial layer of the soil, a location where ticks accomplish their molt and where they oviposit their eggs, making them, theoretically, the preys of infective larvae of nematodes. seventeen strains of entomopathogenous nematodes: eight strains of steinernema and nine strains of heterorhabditis were placed in contact with each of the free living stages of three tick species: amblyomma variegatum, boophil ...19937628227
evaluating the economic damage threshold for bont tick (amblyomma hebraeum) control in zimbabwe.controlling ticks and tick-borne diseases by frequent applications of acaricides (e.g., dipping) is costly, and can leave treated livestock vulnerable to epizootics of tick-borne diseases should the system of applying acaricides break down. the concept of only applying acaricides on an infrequent (strategic) basis often relies on the target tick population displaying a seasonal cycle. however, as adult bont tick (amblyomma hebraeum) infestations in zimbabwe's lowveld do not have a strictly seaso ...19937628230
the effect of inflammatory and hypersensitive reactions, in response to the feeding of the tick amblyomma variegatum, on the progression of experimental dermatophilosis infections.initial infestations of amblyomma variegatum larvae and nymphs, on rabbits and sheep respectively, produced inflammatory reactions in the host's skin; repeated infestations resulted in an increase in development of delayed type hypersensitive reactions. dermatophilus congolensis cocci were applied in titrated doses to hosts at sites of inflammatory or hypersensitive reactions to ticks, and to control hosts with no exposure to ticks. we assessed the resulting infections for three weeks and found ...19937628231
the local effect of hypersensitive or inflammatory reactions to nymphal amblyomma variegatum on simultaneous infections with dermatophilus congolensis.amblyomma variegatum nymphs were applied to sites infected with dermatophilus congolensis on eight rabbits. four rabbits were previously sensitized to the feeding of nymphal a. variegatum to produce hypersensitive reactions to the tick feeding; the remaining four rabbits had no previous exposure to nymphal a. variegatum and produced inflammatory reactions to the tick feeding. the resulting dermatophilosis infections were assessed for three weeks and there was a correlation between the position o ...19937628235
patterns of cuticular hydrocarbon variation and genetic similarity between natural populations of amblyomma cajennense (acari: ixodidae).gas chromatography has been used to analyze the variation in cuticular hydrocarbon patterns between several populations of amblyomma cajennense. 88 compounds were detected and these could be divided into 17 groups of hydrocarbons. heterozygosis in the populations ranges from 0% to 25.84%. isomers for pentacosane, heptacosane and nonatriacontane are the most variable, with 13, 10 and 11 variants, respectively. nei's genetic identity and genetic distance show that populations may be considered as ...19937903139
parasites of domestic and wild animals in south africa. xxxii. ixodid ticks on scrub hares in the transvaal.a total of 264 scrub hares (lepus saxatilis) were examined for ixodid ticks at various localities in the kruger national park, eastern transvaal lowveld. thirteen tick species were recovered from these hares. the seasonal abundances of the immature stages of amblyomma hebraeum, amblyomma marmoreum, hyalomma truncatum, rhipicephalus appendiculatus, rhipicephalus evertsi evertsi, rhipicephalus simus and rhipicephalus zambeziensis and all stages of a rhipicephalus sp. (near r. pravus) were determin ...19937970571
host resistance to ticks (acari: ixodidae) in different breeds of cattle at bako, ethiopia.european cattle breeds are being introduced into ethiopia in an effort to improve the productivity of indigenous breeds. the ethiopian cattle breeds horro and boran were compared for tick burdens with their crosses with friesian, jersey and simmental. horro animals had the lowest tick burdens and the horro x friesian the highest. adaptation to their environment and long-term natural selection for tick resistance in horro cattle is the most likely explanation. repeatability of tick burdens in all ...19938109054
the significance of recent highlights in heartwater research.many of the objectives identified earlier, with regard to research on cowdriosis, have been achieved during the past decade. some contributions such as the development of cowdria specific dna probes and the attenuation of the organisms are still in the experimental stage but others, such as in vitro cultivation, are already well established practices in many laboratories. serological techniques are now more widely used since other methods and other sources of antigen became available. however, p ...19938134619
the relationship between cowdria and ehrlichia: change in the behaviour of ehrlichial agents passaged through amblyomma hebraeum.following an earlier report that an ehrlichia-like agent isolated from an adult hyalomma truncatum female became more pathogenic and elicited a disease in sheep indistinguishable from heartwater after having been passaged through amblyomma hebraeum, a similar phenomenon is herewith recorded. an ehrlichial agent demonstrated in the blood smear of a serologically positive, naturally infected lamb, changed in behaviour and assumed the characteristics of cowdria after passage through a. hebraeum. cr ...19938134623
seroconversion to cowdria ruminantium of malawi zebu calves, reared under different tick control strategies.the seroconversion by indirect elisa to cowdria ruminantium over the first year of life of sixty-six malawi zebu calves born into groups which were dipped 17 times per year was compared to seroconversion of 32 calves born into non-dipped groups. amblyomma variegatum tick counts and clinical disease in each group of cattle were monitored throughout the study period. no cases of heartwater were seen in either group of calves over the first 22 months of life. only one case of heartwater was observe ...19938134628
cowdria ruminantium identified in amblyomma gemma using a dna probe pcs20.amblyomma gemma ticks were collected from wild animals on a 20,000 acre game ranch in a heartwater endemic area in kenya, close to nairobi. a. variegatum is the main vector of heartwater in kenya. e.a. lewis, 1947, in a one sentence report has implicated a. gemma to be a vector of heartwater without giving any details. adult a. gemma were collected from giraffe giraffa camelopardalis, hartebeest alcephalus busephalus, eland taurotragus oryx and ostrich struthio camelus during cropping exercises. ...19938134629
development and transmission of cowdria ruminantium by amblyomma males transferred from infected to susceptible sheep.male amblyomma sp. were tested as vectors of cowdria ruminantium, causative agent of heartwater disease. the males were allowed to feed on sheep experimentally infected with c. ruminantium and then were transferred to susceptible sheep to test for transmission of the rickettsia. the experiments were done in two trials. in the first trial, a. hebraeum were exposed to the palm river stock of c. ruminantium, while in the second trial the kiswani stock of cowdria was tested with a. variegatum. ticks ...19938134630
cowdriosis in senegal: some epidemiological aspects.the results of a study on the abundance of amblyomma variegatum in different ecological zones and of cowdria ruminantium infection rates in nymphal and adult ticks of the north guinean zones are given. joint research is also conducted on the evaluation of seroprevalence. in this study, it appears that the vector is most important in the north guinean zone, followed by the south sudan and the coastal niayes zones. elsewhere, the tick populations are not significant or absent. the infection rate i ...19938134635
the tick vectors of cowdriosis in angola.amongst the amblyomma species presently known to be capable of transmitting cowdria ruminantium six have been recorded in angola. a. pomposum is the most important and widely distributed. of secondary importance are a. variegatum, which prevails in cabinda and moxico provinces, and a. astrion which occurs in the littoral and transition strips and on camabatela plateau. a. sparsum and a. tholloni which are specific parasites of wild hosts are considered accidental vectors. a. hebraeum was introdu ...19938134639
cellular responses in experimental chronic and acute dermatophilosis infections of sheep.the cellular infiltrate into the dermis in dermatophilosis lesions is composed of a range of cell types. the aim of this study was to establish if the composition of the cellular infiltrate in chronic lesions was different from that in healing lesions. experimental dermatophilus congolensis infections of sheep were used to study the sequential changes in cell types during the course of chronic and acute infections. infestations of adult amblyomma variegatum ticks were used to produce chronic les ...19938134642
an attempt to correlate cattle breed origins and diseases associated with or transmitted by the tick amblyomma variegatum in the french west using biological data and historical research, we have tried to explain the difference between resistance and susceptibility to the diseases transmitted (cowdriosis) or associated (dermatophilosis) with the tick amblyomma variegatum, in two cattle breeds of the french west indies: the creole crossbred cattle of guadeloupe and the brahman zebu cattle of martinique. have been studied the polymorphisms of 5 independent genetic systems (erythrocytic haemoglobin, serum albumin and transferrin, the ...19938134643
an attempt to identify genetic markers of resistance or susceptibility to dermatophilosis in the zebu brahman population of martinique.dermatophilosis is a disease associated with the tick amblyomma variegatum, and a genetic predisposition to the manifestation of symptoms has been demonstrated. indeed, the creole cattle of guadeloupe constitute a population which is highly resistant to this disease, whereas the brahman zebu cattle of martinique seem very susceptible. however, in this brahman population there is a gradient regarding the severity of symptoms depending on individuals. in several herds of these pure zebu brahman, k ...19938134644
the epidemiology and control of camel dermatophilosis.camel dermatophilosis was only recently described. it appears however that it is more widespread than originally thought. in kenya it has generally been found in the main semi-arid camel rearing areas of samburu and laikipia districts although it has not yet been found in the arid areas of turkana district. in an investigation of ticks on 200 camels, no amblyomma variegatum ticks were found although many other ticks were present. a. variegatum is suspected to transmit dermatophilosis in many dom ...19938134647
the systemic effect of adult and immature amblyomma variegatum ticks on the pathogenesis of dermatophilosis.the systemic effect of adult and nymphal amblyomma variegatum on the pathogenesis of experimental infections of dermatophilus congolensis was investigated. three groups of four sheep were used with all 12 sheep being infected with identical titrated doses of d. congolensis one group of sheep was simultaneously infested with adult a. variegatum the second with nymphal a. variegatum and the third group were the controls, with no exposure to ticks. assessment of the resulting infections indicate th ...19938134648
the effect of tick control on the prevalence of dermatophilosis on indigenous cattle in ghana.the effectiveness of three tick control regimes on the occurrence of amblyomma variegatum and dermatophilosis on cattle on the coastal plains of ghana were compared. animals at one kraal were sprayed with amitraz at predilection feeding sites of ticks every second week using a high concentration minimum volume technique. animals at two other kraals were treated with a deltamethrin based pour-on acaricide; at one kraal it was applied once every month while at the other kraal it was used at strate ...19938134649
ventilation in the adults of amblyomma hebraeum and a. marmoreum (acarina, ixodidae), vectors of heartwater in southern africa.the objective of this study was to establish the major features of respiratory gas exchange in unfed adults of the ticks amblyomma hebraeum and a. marmoreum, both vectors of heartwater in southern africa. carbon dioxide emission of ticks was measured at 25 degrees c using flow-through respirometry in order to determine standard metabolic rate (smr) and the temporal pattern of gaseous emission. for both species, smr was extremely low and approximately 100 fold less than that predicted for an inse ...19938134650
variability of cattle infestation by amblyomma variegatum and its possible utilisation for tick control.a great variability of the individual infestation by amblyomma variegatum adults was observed on naturally infested gudali zebus. some of the animals (called "attractive for a. variegatum") had a tick burden 10 to 16 times higher than that of the least parasitized cattle of the herd (called "non-attractive"). ranking of the animals based on a. variegatum infestation was correlated for successive tick counts. experiments were designed to determine if the "non-attractive" cattle remained lightly i ...19938134651
acaricides for eradication of the tick amblyomma variegatum in the caribbean.the success of an eradication campaign against the tropical bont tick in the caribbean imposes the use of active acaricide compounds, if possible with residual activity, easy to apply and requiring few or no accessible water supplies and expensive application equipment. tests of in vitro susceptibility of tick strains from puerto rico and guadeloupe as well as observations of the impact of the current tick control campaigns conducted in some caribbean islands, seem to indicate that there is no p ...19938134652
eradication of a new focus of amblyomma variegatum in puerto may 1992 an infestation with the tropical bont tick appeared in a small dairy heifer replacement herd in camuy, puerto rico, a completely new site located near puerto rico's northwest coast. this finding occurred after some three years of no infestation in either puerto rico or the u.s. virgin islands and is not suspected of being associated with any previous infestations. the methods used to eradicate this tick include spray treatment at a two-week interval of all domestic livestock, with am ...19938134653
progress towards a program for the eradication of amblyomma variegatum from the caribbean.amblyomma variegatum (fabricius), the tropical bont tick, is now widely distributed in the caribbean. eighteen islands countries are now or were recently infested with the tick. to stop the spread of this tick to other non-infested islands and to the mainland areas of south, central and north america, a regional eradication program has been proposed and endorsed by the respective governments on each of the amblyomma variegatum infested islands, including the french government and caricom member ...19938134654
[epidemiology of cowdria infection in senegal. i. study of the transmission and infection level in amblyomma variegatum (fabricius, 1794) in the niayes region].the authors report the results of research on infection rates of amblyomma variegatum nympha and imago populations by cowdria ruminantium in the niayes region as well as on the transmission rates of a. variegatum by the various stases. the experiments were carried out on sheep from the sahelian zone where the vector tick is not endemic. the infection rate, estimated by inoculating sheep with ground ticks, gave the following prevalences: t = 13.3% for nymphae and t = 1.2% for adults. the transmis ...19938190980
[epidemiology of cowdria infection in senegal. ii. results of sero-epidemiological follow-up studies].the authors report the results of sero-epidemiological monitoring of zebu, diakoré and ndama cattle in the sahel, niayes and north guinea zones, respectively. calves aged 0-3 or 3-6 months were subjected to blood sampling every three months for a period of 20 months. in the niayes and north guinea zones, the immunofluorescence test showed that about 70% of 0-1 month old calves reacted positively to the cowdria ruminantium antigen, whereas the prevalence was 92% between 3 and 6 months. after the ...19938190981
in vitro feeding of instars of the ixodid tick amblyomma variegatum on skin membranes and its application to the transmission of theileria mutans and cowdria in vitro feeding method using rabbit or cattle skin membranes, applied successfully to all stages (larvae, nymphae and adults) of the ioxodid tick, amblyomma variegatum, is described. the feeding apparatus consisted of a blood container with a membrane placed on top of a tick containment unit. a carbon dioxide atmosphere of between 5 and 10% and a temperature of 37 degrees c were used as stimulants for the attachment of the ticks. high co2 concentrations in the atmosphere improved the feeding ...19938233589
antibodies to cowdria ruminantium in mozambican goats and cattle detected by immunofluorescence using endothelial cell culture antigen.endothelial cell cultures, established from bovine umbilical cord arteries and subsequently infected with cowdria ruminantium, were used as antigen in the indirect fluorescent antibody test. bovine sera (374) and caprine sera (388) collected in 6 provinces of mozambique were tested. overall, 30.4% of goat sera had antibodies to cowdria, and 43% of sera collected from cattle. north of the river save, where the tick amblyomma variegatum is highly prevalent, overall percentages of positive sera wer ...19938236490
cross-mating between amblyomma parvum aragao, 1908 and amblyomma pseudoparvum guglielmone, mangold et keirans, 1990 (acari: ixodidae). 19938244207
impact of natural infestation of amblyomma variegatum on the liveweight gain of male gudali cattle in adamawa (cameroon).the effect of natural tick infestation on the liveweight gain (lwg) of male gudali zebu cattle was studied throughout a year by comparing the performances of two herds, one of which was submitted to weekly acaricidal treatment and the other was left untreated against ticks. six species of ticks were identified on the untreated animals: amblyomma variegatum, boophilus decoloratus, rhipicephalus lunulatus, rhipicephalus turanicus, hyalomma nitidum and hyalomma marginatum rufipes. most of the losse ...19938249253
an immunoblotting diagnostic assay for heartwater based on the immunodominant 32-kilodalton protein of cowdria ruminantium detects false positives in field sera.heartwater, a major constraint to improved livestock production in zimbabwe, threatens to invade areas which have been previously unaffected. to monitor its spread in zimbabwe, an immunoblotting diagnostic assay based on the responses of animals to the immunodominant, conserved 32-kda protein of cowdria ruminantium was evaluated. in this assay, no false reactions were detected with sera known to be positive and negative, but sera from some cattle, sheep, and goats from heartwater-free areas of z ...19938253974
new version of lstsim for computer simulation of amblyomma americanum (acari: ixodidae) population dynamics.a previous version of lone star tick simulation model (lstsim) for a wildlife ecosystem was revised and expanded to include a beef cattle forage area and improved handling of tick-host-habitat interactions. relationships between environmental and biological variables were also refined in the new version. general validity of the revised model was established by comparing simulated and observed host-seeking populations of amblyomma americanum (l.) at five geographic locations, three in oklahoma an ...19938254630
ticks (acari: ixodidae) infesting medium-sized wild mammals in southwestern species of ixodid ticks (n = 2,661) were found on medium-sized wild mammals (n = 295) during a 13-mo study in shelby county, tennessee. the seven tick species collected were dermacentor variabilis (say), amblyomma americanum (l.), rhipicephalus sanguineus (latreille), ixodes texanus (banks), i. cookei (packard), i. scapularis (say), and haemaphysalis leporispalustris (packard). the raccoon had the greatest tick species diversity in all of the aforementioned ticks except h. leporispalustris ...19938254637
potential role of cattle egrets, bubulcus ibis (ciconiformes: ardeidae), in the dissemination of amblyomma variegatum (acari: ixodidae) in the eastern caribbean.the potential role of cattle egrets, bubulcus ibis (l.), in the dissemination of amblyomma variegatum (f.) in the eastern caribbean was evaluated. the status of cattle egrets as hosts for a. variegatum in antigua was determined during seven survey periods between september 1988 and may 1991. the mean prevalences of infestation by larvae and nymphs were 2.3 and 0.5%, respectively. the mean intensity and relative density of infestation by larvae were 8.8 (sd = 9.80) and 0.2 (sd = 0.28), respective ...19938271244
kinetics of male pheromone production by amblyomma variegatum (acari: ixodidae).males of amblyomma variegatum (f.), when attached on their host, produce a pheromonal blend composed of methyl salicylate, ortho-nitrophenol, and nonanoic acid, which acts as an aggregation-attachment pheromone. using olfactometry assays, assays on hosts, and quantification of the compounds by capillary gas chromatography, the kinetics of pheromone production has been studied. males engorged for at least 10 d elicit attachment from most of the tested females. attractiveness of males for females ...19938271253
changes in lipids of the salivary glands of the lone star tick, amblyomma americanum, during feeding.the lipid composition of salivary glands from male and female lone star ticks, amblyomma americanum, was investigated at progressive stages of tick feeding. the amounts of fatty acids from both phospholipid and neutral lipid fractions increased dramatically during the initial stage of feeding and peaked in partially fed females weighing 100-250 mg. percentage compositions of myristic (14:0) and palmitic acid (16:0) decreased, but stearic (18:0), oleic (18:1), linoleic (18:2), and arachidonic aci ...19938277375
first description of the male and redescription of the immature stages of amblyomma rotundatum (acari: ixodidae), a recently discovered tick in the u.s.a.the male of amblyomma rotundatum is described for the first time, and the nymph and larva are redescribed. this tick is a parthenogenetically reproducing species parasitic on amphibians and reptiles in the warmer areas of the new world. attempts to mate male and female a. rotundatum under laboratory conditions were unsuccessful.19938277377
analysis of lipids in the salivary glands of amblyomma americanum (l.): detection of a high level of arachidonic acid.analysis of lipids in salivary glands of the lone star tick, amblyomma americanum, demonstrated that arachidonic acid (20:4, n-6) comprises 8% of all fatty acids identified by gas chromatography. the occurrence of arachidonic acid and other c20 polyunsaturated fatty acids in tick salivary glands was confirmed by gas chromatography-mass spectrometry. arachidonate is located entirely in the phospholipid fraction and is associated exclusively with phosphatidylcholine (pc) and phosphatidylethanolami ...19938324244
isolation and transmission of the lyme disease spirochete from the southeastern united states.the isolation of the lyme disease spirochete (borrelia burgdorferi) from the southeastern united states is reported. three isolates, two from cotton mice (peromyscus gossypinus) and one from the black-legged tick (ixodes scapularis), were recovered from sapelo island, georgia, in july and september 1991. the spirochetes were characterized by indirect fluorescent antibody assay using a battery of five monoclonal antibodies, by sodium dodecyl sulfate/polyacrylamide gel electrophoresis (sds/page) o ...19938346258
amblyomma americanum: a potential vector of human ehrlichiosis.polymerase chain reaction primers specific for ehrlichia chaffeensis were used to amplify dna from extracts of pooled ticks. amplification was performed on extracts from 140 pools (1,579 total ticks) consisting of three tick genera collected from five states. the characteristic 389-basepair product was observed after amplification of extracts from seven different pools of adult amblyomma americanum (117 pools, 1,462 ticks), but not from pools of nymphs. no specific product was observed after amp ...19938357086
progress in research on tick-borne diseases: theileriosis and heartwater.the rapid population growth in subsaharan africa necessitates a great increase in animal production in the more humid zones. vector-borne diseases occurring in these zones will assume more importance, but are difficult to control. they include theileriosis and heartwater. recent developments in research on these diseases are presented. indigenous animal populations in endemic areas, subjected to natural selection, are far less susceptible than exotic stock. heartwater, caused by the rickettsia c ...19938372422
establishment of the foreign partheonogenetic tick amblyomma rotundatum (acari: ixodidae) in florida.the parthenogenetic tick amblyomma rotundatum, a central and south american species, has become established in southern florida. the date of introduction is unknown, but it is suspected to be either during the 1930s, when 1 of its natural hosts, the giant or marine toad, bufo marinus, was introduced to southern florida as a potential biological control of pest beetles in sugar cane fields, or between 1955 and 1964 when specimens of b. marinus were accidentally or deliberately released in the gre ...19938410557
detection of cowdria ruminantium by means of a dna probe, pcs20 in infected bont ticks, amblyomma hebraeum, the major vector of heartwater in southern africa.a dna probe, pcs20, previously described for use in detection of cowdria ruminantium infections in amblyomma variegatum (the principal vector of heartwater) hybridized with c. ruminantium dna in organs of laboratory-infected a. hebraeum adult ticks (the major southern african vector of heartwater). the probe hybridized with c. ruminantium dna in 46/49 midguts from male ticks and 26/29 from females, thus indicating infection. corresponding salivary glands were less heavily infected, but infection ...19938432329
implications of selection and hybridization studies on the mode of inheritance of photoperiodically induced developmental diapause in laboratory strains of the lone star tick (acari: ixodidae).selection of lone star ticks, amblyomma americanum (l.), that were reared in the laboratory under short-day photoperiods of 10:14 (l:d) h resulted in third generation (f3) diapause versus f3 nondiapause strain replete nymphs having significantly different mean molting times (days from detachment to ecdysis) of 100.9 versus 54.7 d, respectively; whereas, the f7 unselected laboratory control strain had an even smaller, significantly different mean molting time of 49.5 d. two hybrid crosses of f2 n ...19938433316
experiments on the relationship between feeding of the tick amblyomma variegatum (acari: ixodidae) and dermatophilosis skin disease in sheep.experiments on the systemic effect of feeding adult amblyomma variegatum (f.) on dermatophilosis caused by dermatophilus congolenis in six sheep were performed by feeding ticks at sites separate from sites of experimental infection with d. congolensis. comparisons were made with d. congolensis infections on six control sheep without ticks. tick-infested sheep developed chronic dermatophilosis lesions; tick-free sheep healed rapidly. on two tick-infested and two control sheep a chronological sequ ...19938433320
differential recognition of saliva antigens from the ixodid tick amblyomma hebraeum (acari: ixodidae) by sera from infested and immunized rabbits.we determined the protein composition and antigenic content of saliva from amblyomma hebraeum female ticks of different weight classes. the mean protein concentration of saliva of small partially fed ticks (< 100 mg) was 333 +/- 83 micrograms/ml and that of large partially fed ticks (150-420 mg) was 59 +/- 14 micrograms/ml. the reduction in concentration mostly was caused by the significantly higher fluid volume per minute secreted by large ticks. polypeptide analysis of saliva indicated the pre ...19938433335
effects of temperature on fecundity and viral replication in amblyomma cajennense (arachnida: ixodidae) infected with venezuelan equine encephalomyelitis assess how temperature affects fecundity and venezuelan equine encephalomyelitis (vee) viral replication in vee-infected amblyomma cajennense (f.), adult ticks were inoculated intracoelomically with either vee virus (i-a variant) or diluent. ticks were held at 19, 26, or 33 degrees c and tested for vee virus over 20 d. up to 10 pairs of ticks (1 female:1 male) from each temperature group were allowed to feed on guinea pigs on day 8 after inoculation. maximum titers did not differ significantl ...19938433340
parasitic arthropods of sympatric opossums, cotton rats, and cotton mice from merritt island, florida.six species of parasitic arthropods were collected from 12 opossums (didelphis virginiana), 8 species were obtained from 28 cotton rats (sigmodon hispidus), and 4 species were collected from 10 cotton mice (peromyscus gossypinus) from merritt island, brevard county, florida. the flea polygenis gwyni was the only parasite that infested all 3 host species, and it was present in very high densities (mean intensity = 73.7) on the opossums. the american dog tick, dermacentor variabilis, and the tropi ...19938459341
a comparison of field tick infestation on n'dama, zebu and n'dama x zebu crossbred cattle.tick burdens, estimated from cumulative tick counts, were determined on n'dama, zebu and f1 n'dama x zebu crossbred cattle. n'dama showed significantly fewer ticks than the zebu and f1 cattle (p < 0.001). a previous trypanosomosis infection did not affect tick burdens on the three genotypes. amblyomma variegatum had a prevalence of 84.8% and hyalomma spp. 15.2%, with the ratio similar on all cattle breeds. trypanosomosis infection increased the serological prevalence of anaplasma marginale in ze ...19938493760
ixodid ticks (acari: ixodidae) and livestock production: effect of varying acaricide treatments on ticks and productivity in east coast fever-immunized weaner and dairy a pilot trial to evaluate cost-effective methods of acaricide application, east coast fever-immunized weaner and dairy cattle were subjected to varying tick control regimens. all experimental cattle were maintained under the same extensive system of management. their monthly tick load, packed cell volumes, incidence of blood protozoans, weight changes, and daily milk production were noted. apart from rhipicephalus appendiculatus neumann, other tick species found in the study site were r. pulc ...19938510109
computer-controlled olfactometer system for studying behavioral responses of ticks to carbon olfactometer system that consisted of a laptop computer, a carbon dioxide analyzer, and an apparatus to control gas flows was designed to study ixodid tick behavioral responses to varying carbon dioxide (co2) concentrations. the system provided a method to regulate and measure stimulatory co2 concentrations (1-99 ppm) above ambient co2 background levels. adult amblyomma americanum (l.) and dermacentor variabilis (say) demonstrated behavioral responses to co2 concentrations as low as 9 ppm abo ...19938510116
ticks (acarina: ixodidae) of reptiles from central, lusaka and southern provinces of zambia.during the period 1988-1991, reptiles (23 snakes, 36 tortoises, 25 chameleons and 2 monitor lizards) from central, lusaka and southern provinces of zambia were caught and checked for ticks. only 2 snakes, respectively one python sebae (gmelin, 1789) and one bitis arietans (merrem, 1820), 8 tortoises, respectively seven geochelone pardalis (bell, 1828) and one kinixys belliana (gray, 1831) were found infested with a small number of ticks: nymphs and adults of aponomma latum (koch, 1844) and ambly ...19938065818
[ticks and hemoparasitoses in livestock in senegal. v. the northern guinea area].the authors report the results of a study on ticks and hemoparasitoses among cattle, sheep and goats in the north-guinean zone. during a period of 15 months, ticks were systematically removed from 40 cattle, 40 sheep and 40 goats in order to assess the population dynamics and to determine more accurately the preferential sites of settlement of the following different species collected from these animals: amblyomma variegatum, boophilus geigyi, hyalomma truncatum, h. marginatum rufipes, rhipiceph ...19938073170
[the acquisition of resistance by laboratory mice to amblyomma hebraeum (ixodidae) larvae].repeated feedings of larval amblyomma hebraeum ticks on laboratory mice results in strong decrease of engorged tick yield (from 65-73% after primary feeding to 11% after secondary feeding). laboratory mice differ essentially in this respect from rabbits and sheep which are unable to acquire the resistance (see norval, 1978) to larvae of this tick.19938152843
epidemiological studies on dermatophilosis in the caribbean.dermatophilosis is one of the most important diseases of domestic ruminants in the caribbean islands where the clinical disease has been shown to be associated with the presence of the tick amblyomma variegatum. seroepidemiological studies were conducted to clarify the epidemiology of the disease in the region with a particular attention paid to the role of a. variegatum. a bank of 1300 cattle sera from the lesser antilles was screened by elisa for the presence of antibodies to dermatophilus con ...19938161379
observations on cattle ticks in huila province (angola).in huila province of angola, 3864 ticks were collected during a parasitological survey carried out in the rainy season from october 1990 to april 1991. the samples were collected from cattle gathered for the annual vaccination campaign against contagious bovine pleuropneumonia, anthrax and blackleg in 18 veterinary stations of six municipalities. after tick classification, the following proportions of ticks were obtained: rhipicephalus evertsi mimeticus (27.1%), amblyomma pomposum (26.4%), booph ...19948171837
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