Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| characterization of ixodid tick salivary-gland gene products, using recombinant dna technology. | ticks secrete an array of lesion-maintenance factors into the host via the salivary glands while feeding, some of which elicit an immune response by the host that adversely affects the ability of the tick to feed and reproduce. our approach to characterizing these factors has been to make expression libraries from mrna of salivary glands (from unfed and 3-day-feeding amblyomma americanum females) which will serve as sources of the genes (clones) that code for them. thus far, we have detected 10 ... | 1989 | 2758938 |
| habitat use by cattle affects host contact with lone star ticks (acari: ixodidae). | the location of zebu, british, and zebu x british cattle in tick-infested plots from march through september 1986 was compared with the location of amblyomma americanum l. in the same plots. in april, may, and june, zebu cattle spent less time (9.3-19.4%) in tick-infested quadrats than british (44.4-63.9%) or zebu-british (49.0-69.3%) cattle. in the same months, the probability that a. americanum would contact zebu cattle (1.5-19.6%) was significantly lower than for british (34.7-41.7%) or zebu- ... | 1989 | 2754101 |
| spectral sensitivity, absolute threshold, and visual field of two tick species, hyalomma dromedarii and amblyomma variegatum. | 1. the spectral sensitivity in the wavelength range of 340-750 nm was determined by both a behavioral approach based on spontaneous positive phototaxis and the electroretinogram (erg). 2. concerning phototaxis the camel tick, hyalomma dromedarii, showed two sensitivity maxima, one in the uv range (ca. 380 nm) and another in the blue-green range (ca. 500 nm). at higher intensities the relative sensitivity was more pronounced in the uv and at lower intensities more pronounced in the blue-green (re ... | 1989 | 2746548 |
| sites of attachment and density assessment in amblyomma americanum (acari: ixodidae) on nursing beef calves. | primary attachment sites of male, female, and nymphal amblyomma americanum (l.) on nursing beef calves were the axillary, inguinal and perianal areas of the body. about 50% of all larvae fed on the ears. a density assessment method which uses the number of a. americanum on less than or equal to 5 body areas to predict the total number of ticks (tick burden) on the left side of a calf is presented. estimates of tick burden for male, female, nymphal and larval a. americanum each require examinatio ... | 1989 | 2714123 |
| evaluation of the eradication program for amblyomma variegatum (acari:ixodidae) on puerto rico. | a cooperative effort between the united states department of agriculture, animal and plant health inspection service, veterinary services, the agricultural research service, and the department of agriculture, commonwealth government of puerto rico has been successful in eradicating amblyomma variegatum (fabricius) from the islands of puerto rico and vieques (an island municipality of puerto rico). application of acaricides to livestock and dogs at 14-day intervals for an 18-month period eliminat ... | 1989 | 2707108 |
| a mouse lethal dose assay for detection and titration of cowdria ruminantium (kwanyanga strain) in goats and ticks. | a mouse lethal dose assay was used to detect a mouse pathogenic strain (kwanyanga) of cowdria ruminantium, the etiological agent of heartwater in goats and ticks. the titer of the rickettsial organisms in goat blood was directly related to the febrile response of the goat and the rickettsia were undetectable after the fever subsided. the maximum rickettsial titer in goat blood was 10(3) mouse ld50 ml-1. cowdria-infected goat blood was shown to retain infectivity when held on ice for up to 2 h, b ... | 1989 | 2705290 |
| [the coevolution of ixodid ticks and terrestrial vertebrates]. | paleontologic and zoogeographic data speak in favour of mesozoic origin of ixodid ticks. the absence of strict restrictions for the feeding on unusual species of hosts has caused the domination of polyphagy and oligophagy over monophagy among ixodid ticks. the same peculiarities of ixodid ecology are responsible for a restricted part or absence of phylogenetic parallelism with hosts in their evolution. primary food relations with reptiles are, apparently, preserved only in the genus aponomma and ... | 1989 | 2694077 |
| transmission of lyme disease spirochetes (borrelia burgdorferi). | the field and laboratory evidence incriminating nymphal ixodes dammini as the main vectors of borrelia burgdorferi is substantial. furthermore, other members of the ixodes (ixodes) ricinus 'complex', including i. ricinus, i. persulcatus, i. pacificus, and i. scapularis, are competent vectors of the lyme disease spirochete. although ticks in other genera are also naturally infected with b. burgdorferi, experimental evidence suggests that amblyomma and dermacentor ticks are inefficient vectors of ... | 1989 | 2667921 |
| the host status of the striped mouse, rhabdomys pumilio, in relation to the tick vectors of heartwater in south africa. | striped mice, rhabdomys pumilio, were trapped over a 17 month period in the thomas baines nature reserve in the eastern cape province of south africa. captured mice were placed in cages, over water, and naturally detaching ticks were collected. only 5 larvae and 1 nymph of amblyomma hebraeum were recovered from the mice. these represented less than 0.1% of the total number of ticks recovered. no amblyomma marmoreum were recovered. as the vegetation and large mammals and tortoises in the thomas b ... | 1989 | 2626267 |
| resistance of nguni, bonsmara and hereford cattle to ticks in a bushveld region of south africa. | counts of engorged female ticks on naturally infested cattle over a 2 year period, showed that indigenous nguni cattle harboured significantly fewer amblyomma hebraeum, boophilus decoloratus and hyalomma spp. during periods of peak abundance than either bonsmara or hereford cattle. fewer abscesses, associated with tick bite, were also present in the nguni cattle. individual tick resistance indices, determined after artificial tick infestation in the field, could not be correlated with hair lengt ... | 1989 | 2626263 |
| parasite survey of eight wild animals in the ruma national park. | eight game animals representing seven species in the ruma national park in south nyanza, kenya, were examined for the presence of blood protozoa, ectoparasites, and helminthic and coccidian endoparasites using standard parasite-identification methods. haematological parameters were also determined. the oribi was positive for trypanosoma brucei ssp. and the reedbuck for t. congolense. no other blood protozoans were found. strongyle eggs were found in the faeces of all species except the water buc ... | 1989 | 2619384 |
| the carrier status of sheep, cattle and african buffalo recovered from heartwater. | sheep, cattle and the african buffalo (syncerus caffer) were shown to remain carriers of heart-water (caused by cowdria ruminantium) for long periods after recovery; 223, 246 and 161 days, respectively. transmission was achieved using adults of the southern african bont tick (amblyomma hebraeum) that had fed as nymphs on recovered animals. our findings differ from those of other workers who attempted transmission using nymphs that had fed as larvae on recovered animals or with blood from recover ... | 1989 | 2617830 |
| [the efficacy of alphamethrin-impregnated ear tags against ticks]. | the efficacy of 3 kinds of alphamethrin-impregnated ear tags was tested against natural amblyomma hebraeum, boophilus decoloratus, rhipicephalus appendiculatus, and rhipicephalus evertsi evertsi infestations of cattle. one type of ear tag was also tested in combination with a tail band of similar material. ticks were counted macroscopically on their predilection sites. counts of b. decoloratus, r. appendiculatus, and r. e. evertsi on all trial animals diminished steadily during the first 7d afte ... | 1989 | 2607535 |
| control of lone star ticks (acari: ixodidae) on spanish goats and white-tailed deer with orally administered ivermectin. | ivermectin administered orally to spanish goats, capra hircus (l.), or to white-tailed deer, odocoileus virginianus (zimmerman), was highly effective against lone star ticks, amblyomma americanum (l.). for spanish goats, daily oral doses of 20 micrograms/kg resulted in greater than or equal to 2 ppb ivermectin in the blood. this level was sufficient to cause greater than 95% reduction of estimated larvae from feeding ticks. a bioassay with horn flies, haematobia irritans (l.), was developed to e ... | 1989 | 2607030 |
| the role of males of the bont tick (amblyomma hebraeum) in the transmission of cowdria ruminantium (heartwater). | the role of males of the bont tick (amblyomma hebraeum) in the transmission of cowdria ruminantium (heartwater) was investigated. transstadial (nymph to adult) and intrastadial transmission were demonstrated. males transferred from live or dead hosts to live hosts were shown to transmit c. ruminantium repeatedly. it was concluded that male transmission is of importance in the epidemiology of heartwater. | 1989 | 2588467 |
| rejection of ticks from guinea pigs by anti-hapten-antibody-mediated degranulation of basophils at cutaneous basophil hypersensitivity sites: role of mediators other than histamine. | previous studies have established that recruitment of basophils to sites of tick feeding in guinea pigs is required to effect immune resistance. in the current study, actively sensitized guinea pigs treated three times daily with h-1 (mepyramine) and h-2 (cimetidine) histamine receptor antagonists, during the challenge tick infestation period, expressed normal resistance to amblyomma americanum larvae. similarly, naive guinea pigs treated with anti-histamines four times daily, beginning 7 days b ... | 1985 | 2578152 |
| resistance and cross-resistance in guinea-pigs and rabbits to immature stages of ixodid ticks. | infestation of guinea-pigs and rabbits with larvae of any one of five species of ticks, rhipicephalus appendiculatus neumann, rhipicephalus evertsi evertsi neumann, amblyomma hebrauem koch, amblyomma variegatum fabricius and ixodes ricinus l., conferred resistance in the animals when exposed to subsequent infestations with the same tick species. resistance to infestations by other tick species was not observed. | 1989 | 2519683 |
| effect of tick control on liveweight gain of cattle in central zambia. | field trials were carried out during 1982-86 in two different ecotypes in central zambia to determine the impact of tick control on the liveweight gain (lwg) of cattle. during the first 2 years of the trial a diamidide acaricide (amitraz) sprayed at weekly intervals caused periodic depression in lwg in young animals. thereafter a pyrethroid acaricide (cypermethrin) was used. during the 1984-85 tick season infestations of 50-120 adult amblyomma variegatum fabricius in untreated animals caused sig ... | 1989 | 2519678 |
| ecological aspects of cattle tick control in central zambia. | in ecological studies in central zambia, both climate and ecotype affected population dynamics of tick species. below average rainfall for several years caused a suppression in numbers of rhipicephalus appendiculatus neumann adults. reduction in rainfall leading to changes in grazing patterns is thought to have been responsible for an increase in numbers of amblyomma variegatum fabricius adults in a grassland habitat. there were reasonable correlations between numbers of each tick species on ind ... | 1989 | 2519677 |
| vector capacity of rhipicephalus appendiculatus and amblyomma variegatum for thogoto and dhori viruses. | experimental studies were undertaken to ascertain the vector potential of rhipicephalus appendiculatus neumann and amblyomma variegatum fabricius for thogoto (tho) and dhori (dho) viruses, candidate members of the orthomyxoviridae. in the first set of experiments, ticks were infected orally by feeding on viraemic hamsters. tho virus replicated in r. appendiculatus and a. variegatum, persisted trans-stadially in both tick species, and was transmitted to susceptible hosts during feeding. in contra ... | 1989 | 2519663 |
| difference in vector competence of two species of sympatric ticks, amblyomma variegatum and rhipicephalus appendiculatus, for dugbe virus (nairovirus, bunyaviridae). | amblyomma variegatum was shown to be a competent vector of dugbe (dug) virus whereas rhipicephalus appendiculatus was not. when dug virus was taken up orally by a. variegatum nymphs, during capillary feeding, the virus replicated and persisted through moulting to the following adult stage. in contrast, although dug virus replicated in capillary fed r. appendiculatus nymphs, the virus did not persist trans-stadially into the adult stage. if the oral route of infection was by-passed by direct inoc ... | 1989 | 2510418 |
| ectoparasitic acari found on golden lion tamarins (leontopithecus rosalia rosalia) from brazil. | anesthetized golden lion tamarins (leontopithecus rosalia rosalia), a highly endangered species, were examined for ectoparasites by brushing the fur and swabbing the ears. ectoparasites recovered from the fur included four species of immature ticks (amblyomma spp.), three species of chiggers (euschoengastia sp., microtrombicula brennani and speleocola tamarina), and one species of follicular mite (rhyncoptes anastosi). ectoparasites do not seem to be of particular significance to the health of t ... | 1989 | 2503627 |
| experimental infection of six species of ixodid ticks with dugbe virus (family bunyaviridae, genus nairovirus). | the vector potential of each of 6 species of colonized north american and african ixodid ticks was assessed by intracoelomic inoculation with dugbe virus (ibar 1792, 14th passage in suckling mouse brain) and viral titers were monitored after selected incubation periods. persistence of dugbe virus for greater than or equal to 53 days in 5 species (dermacentor andersoni, d. variabilis, amblyomma americanum, rhipicephalus appendiculatus, and r. sanguineus) indicates that infection occurred. viral t ... | 1989 | 2496609 |
| experimental studies on the replication and transmission of crimean-congo hemorrhagic fever virus in some african tick species. | seven african tick species were studied as potential vectors of crimean-congo hemorrhagic fever (cchf) virus. engorged nymphae of 4 ixodid species, hyalomma marginatum rufipes, h. truncatum, rhipicephalus evertsi mimeticus, and amblyomma hebraeum, were inoculated intracoelomically with cchf virus and assayed for virus content at varying times post-inoculation. the virus replicated in all 4 species, reaching maximum titers of 4.6-5.5(10) fluorescence focus units per ml on days 5-9 post-inoculatio ... | 1989 | 2494900 |
| [dermatophilus congolensis bovine dermatophilosis in the french west indies. iii. a comparison between infected and non-infected cattle]. | the determination of the distinctive features between infected and uninfected cattle by dermatophilus has been performed among 93 bovine stock in la martinique, and 120 in la guadeloupe and saint-martin islands. nearly half of the herds had been or were infected. morbidity rates reach 33 per cent in la martinique and 29 per cent in la guadeloupe with a mortality ratio of 15 per cent and 5 per cent respectively. no frequency difference could be observed with respect to the season or the geographi ... | 1989 | 2485539 |
| resistance of brahman and hereford cattle to african ticks with reference to serum gamma globulin levels and blood composition. | field collections of ticks from two breeds of cattle showed that the common species of ticks were amblyomma hebraeum, rhipicephalus appendiculatus and rhipicephalus evertsi evertsi. the density of these species was higher on hereford than on brahman cattle. the results also indicated that the density of immature stages of the above-mentioned ticks is higher on hereford than on brahman cattle. a positive correlation was found between the number of ticks on the cattle and the serum gamma globulin ... | 1987 | 2456184 |
| western blot analysis of amblyomma americanum-derived stage-specific and shared antigens using serum from guinea pigs expressing resistance. | serum from guinea pigs expressing resistance to larval, nymphal and adult amblyomma americanum ticks was used in western blot analyses to identify potential antigens from egg, larval and nymphal, and female salivary gland extract preparations. the results demonstrate multiple antigens unique to each life stage, as well as several shared proteins between the three life stages. however, it appears as if two particular proteins of 25 and 38 kda may be more important than others, based upon their pr ... | 1988 | 2455376 |
| distinctive staining of colonies of cowdria ruminantium in midguts of amblyomma hebraeum. | mallory's phloxine-methylene blue stain was used to differentiate colonies of cowdria ruminantium in midgut epithelial cells of nymphal amblyomma hebraeum that had been infected as larvae. gut tissues were collected from nymphs that had fed on a susceptible sheep and were fixed in formol-saline on the day of repletion. paraffin sections, 3-4 micron thick, were then stained and this rendered colonies and cell nuclei densely blue against a uniformly pink background of tick tissues. colonies were e ... | 1987 | 2452397 |
| 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, ... | 1990 | 2399648 |
| 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 ... | 1990 | 2388239 |
| 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 ... | 1990 | 2388237 |
| 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 ... | 1990 | 2380870 |
| 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 ... | 1990 | 2378448 |
| 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 ... | 1990 | 2368951 |
| 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 ... | 1990 | 2350995 |
| ecological aspects of four species of ticks found on cattle in salta, northwest argentina. | the seasonal activity of amblyomma cajennense, amblyomma neumanni, amblyomma parvum and boophilus microplus on cattle was studied in a ranch located in the northern part of the phytogeographical district of the chaco serrano where the habitat had suffered minimal human disturbance. the female ticks on one side of 10-25 cows were counted at intervals of 20-50 days from 29 october 1985 to 5 november 1986. the percentage of cattle parasitized with larvae and nymphs of amblyomma was recorded, along ... | 1990 | 2343535 |
| resistance of brahman and simmentaler cattle to southern african ticks. | field collections of ticks from two breeds of cattle in the north western transvaal showed the common tick species to be rhipicephalus appendiculatus, amblyomma hebraeum, rhipicephalus evertsi evertsi and hyalomma marginatum rufipes. the number of these ticks was higher on simmentaler than on brahman cattle. correlation was found between the number of ticks on the cattle and their serum gamma globulin levels indicating an increase in the production of antibodies. similar correlation was also fou ... | 1990 | 2339000 |
| histological reactions to bites of amblyomma variagatum and rhipicephalus appendiculatus (acari: ixodidae) fed simultaneously on naive or sensitized rabbits. | histopathological studies on attachment sites of nymphs, 48 h after attachment on three groups of rabbits, have revealed differences that were related to the rabbits' previous tick experience. feeding lesions caused by amblyomma variegatum (f.) in tick-naive rabbits were extensive and the total number of inflammatory cells was about 10 times greater than that in the feeding lesions caused by rhipicephalus appendiculatus neumann fed simultaneously on contralateral ears. rabbits that were previous ... | 1990 | 2332876 |
| ticks (acari: ixodidae) of the nile monitor on rusinga island, kenya. | in the course of a study of ticks of livestock, five nile monitor lizard specimens were caught and examined for ticks. although none of the tick species infesting livestock were found on the reptiles, a large number of adults and presumed nymphs and larvae of aponomma flavomaculatum (lucus) and adults of amblyomma sparsum (neumann) were collected. the ticks demonstrated a distinct predilection for their attachment sites. this is the second report of a. flavomaculatum from this part of kenya. | 1990 | 2332875 |
| [interrelatio of acari ixodidae and hosts of edentata of the serra da canastra, minas gerais, brazil]. | we received for examination a small colection of ticks captured in the national park of the serra da canastra (mg), between 1979 and 1980. the authors demonstrated the existence of a broad co-accomodation of amblyomma pseudoconcolor on edentata of the family dasypodidae, being dasypodini the tribe more adjusted to this infestation. in conformity to the figs 1 and 2, dasypodini are probably the real hosts of a. pseudoconcolor and also the oldest hosts. for the first time, a. pseudoconcolor is als ... | 1989 | 2319951 |
| 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 ... | 1990 | 2307070 |
| 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. | 1990 | 2301128 |
| 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 ... | 1990 | 2298277 |
| 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. | 1990 | 2293132 |
| 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 ... | 1990 | 2286996 |
| 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 ... | 1990 | 2284130 |
| 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 ... | 1990 | 2267728 |
| [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 ... | 1990 | 2263738 |
| 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 ... | 1990 | 2261818 |
| [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 ... | 1990 | 2259524 |
| 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 ... | 1990 | 2250335 |
| 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 ... | 1990 | 2231620 |
| 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 ... | 1990 | 2231613 |
| 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 ... | 1990 | 2226074 |
| 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 ... | 1990 | 2226073 |
| [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 ... | 1990 | 2218038 |
| [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 ... | 1990 | 2218032 |
| 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 ... | 1990 | 2166447 |
| [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 ... | 1990 | 2135470 |
| 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 ... | 1990 | 2132999 |
| 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 ... | 1990 | 2126618 |
| 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 ... | 1990 | 2126617 |
| [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 ... | 1990 | 2103050 |
| 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 ... | 1990 | 2096521 |
| 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 ... | 1990 | 2081445 |
| 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. ... | 1990 | 2080832 |
| 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 ... | 1991 | 2063950 |
| hyperosmotic oral fluid secretion during active water vapour absorption and during desiccation-induced storage-excretion by the unfed female tick amblyomma americanum. | 1991 | 2061709 | |
| drag-sampling of free-living ixodid ticks in the kruger national park. | free-living 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 ... | 1991 | 2052317 |
| 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 ... | 1991 | 2051439 |
| 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 ... | 1991 | 2044433 |
| 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. | 1991 | 2040963 |
| 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 ... | 1991 | 2033602 |
| 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, ... | 1991 | 2023323 |
| 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 ... | 1991 | 2014622 |
| tick information sheet. the lone star tick. amblyomma americanum. | 1991 | 2014616 | |
| 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 ... | 1991 | 2007631 |
| 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 ... | 1991 | 1987531 |
| 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 ... | 1991 | 1949146 |
| 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 ... | 1991 | 1941943 |
| 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 ... | 1991 | 1941936 |
| 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, ... | 1991 | 1941933 |
| 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 ... | 1991 | 1941930 |
| 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) ... | 1991 | 1941925 |
| mechanisms of host-tick contact with special reference to amblyomma americanum (acari: ixodidae) in beef cattle forage areas. | at 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 ... | 1991 | 1941920 |
| 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 ... | 1991 | 1941917 |
| 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 ... | 1991 | 1928798 |
| 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 ... | 1991 | 1923381 |
| 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 ... | 1991 | 1923375 |
| 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 ... | 1991 | 1923373 |
| 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 ... | 1991 | 1919918 |
| 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 ... | 1991 | 1919917 |
| 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 ... | 1991 | 1916533 |
| 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. | 1991 | 1909066 |
| 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. ... | 1991 | 1907050 |
| 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 ... | 1991 | 1893800 |
| 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 ... | 1991 | 1893799 |
| 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 ... | 1991 | 1882498 |
| 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 ( ... | 1991 | 1881661 |
| 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 ... | 1991 | 1875376 |