| susceptibility and carrier status of impala, sable, and tsessebe for cowdria ruminantium infection (heartwater). | three species of wild african ruminants, impala (aepyceros melampus), sable (hippotragus equinus), and tsessebe (damaliscus lunatus), were experimentally inoculated with in vitro culture-derived cowdria ruminantium organisms, the tick-borne causative agent of heartwater in domestic ruminants, to determine their susceptibility to infection. no clinical disease was observed in any of the ruminants. however, c. ruminantium was detected in the sable by the transmission of heartwater to susceptible s ... | 1999 | 10386439 |
| cowdria ruminantium infection in ticks in the kruger national park. | adult amblyomma hebraeum ticks, the principle vector of heartwater (cowdriosis) of domestic ruminants in southern africa, were collected in pheromone traps placed in kruger national park, an exclusively wildlife sanctuary in south africa. these ticks transmitted cowdria ruminantium, the rickettsial agent causing heartwater, to a susceptible goat, resulting in acute, fatal disease. c ruminantium was isolated in bovine endothelial cell culture from the plasma of this animal during the febrile stag ... | 1999 | 10515616 |
| prevalence of cowdria ruminantium infection in amblyomma hebraeum ticks from heartwater-endemic areas of zimbabwe. | analysis of the transmission dynamics of cowdria ruminantium, the tick-borne rickettsial agent of heartwater in ruminants, requires accurate measures of infection in vector populations. to obtain these, amblomnia hebraeum ticks were collected at two heartwater-endemic locations in the lowveld and highveld regions of zimbabwe and assessed for c. ruminantium infection with specific polymerase chain reaction (pcr) and dna probe detection assays. at the lowveld site, 11.2% (50/446) of adult ticks an ... | 1999 | 10579452 |
| parasites of domestic and wild animals in south africa. xxxvii. ixodid ticks on cattle on kikuyu grass pastures and in valley bushveld in the eastern cape province. | individual calves, exposed to infestation for 14 d on dry-land kikuyu grass pastures on the coast near alexandria, were slaughtered at approximately monthly intervals over a period of 2 years and examined for ticks. although seven species were recovered total tick burdens were for the most part low. changing the acaricide with which other cattle on the farm, but not the survey calves, were treated from an organophosphate-based compound to a synthetic pyrethroid resulted in a marked sustained red ... | 1999 | 10631707 |
| the occurrence of theileria and cowdria parasites in african buffalo (syncerus caffer) and their associated amblyomma hebraeum ticks. | the polymerase chain reaction and oligonucleotide probing were used to detect theileria and cowdria species in dna extracted from blood and ticks recovered from 24 african buffalo during a gamecapture operation in the kruger national park, south africa. species-specific probing indicated that all but one of the buffalo were carrying at least one theileria species. indirect fluorescent antibody (ifa) serology indicated that all animals had been exposed to theileria parva infection but only 33% we ... | 1999 | 10631711 |
| responses of the tropical bont tick, amblyomma variegatum (fabricius), to its aggregation-attachment pheromone presented in an air stream on a servosphere. | male amblyomma variegatum ticks feeding on a host release a mixture of o-nitrophenol and methyl salicylate which serves to attract conspecifics. the behavioural responses of a. variegatum on a servosphere to these volatiles presented in an air stream are detailed here. in still air, ticks walked on all eight legs, but with long halts. in contrast, the air stream caused continuous walking and induced a reaching response where the forelegs actively sampled the air. such reaching increased the angu ... | 2000 | 10659046 |
| growth of cowdria ruminantium, the causative agent of heartwater, in a tick cell line. | the tick-borne rickettsia cowdria ruminantium has been propagated continuously for over 500 days in the ixodes scapularis tick cell line ide8 by using the gardel isolate from bovine endothelial cells as an inoculum. infection of the tick cells was confirmed by pcr, karyotyping, electron microscopy, and reinfection of bovine cells. | 2000 | 10699030 |
| comparison of efficacy of american and african amblyomma ticks as vectors of heartwater (cowdria ruminantium) infection by molecular analyses and transmission trials. | the ability of amblyomma americanum, amblyomma cajennense, amblyomma maculatum, and amblyomma variegatum to acquire and transmit cowdria ruminantium infection was investigated. uninfected nymphs were fed on clinically reacting c. ruminantium-infected sheep and then analyzed for infection by specific dna detection assays and by tick transmission trials. by polymerase chain reaction (pcr), the mean infection prevalence of a. maculatum ticks (50.7%) was similar to that of a. variegatum, elevage str ... | 2000 | 10701562 |
| detection of the agent of heartwater, cowdria ruminantium, in amblyomma ticks by pcr: validation and application of the assay to field ticks. | we have previously reported that the pcs20 pcr detection assay for cowdria ruminantium, the causative agent of heartwater disease of ruminants, is more sensitive than xenodiagnosis and the pcs20 dna probe for the detection of infection in the vector amblyomma ticks. here, we further assessed the reliability of the pcr assay and applied it to field ticks. the assay detected dna of 37 isolates of c. ruminantium originating from sites throughout the distribution of heartwater and had a specificity ... | 2000 | 10747140 |
| macrorestriction fragment profiles reveal genetic variation of cowdria ruminantium isolates. | macrorestriction profile analysis by pulsed-field gel electrophoresis (pfge) was used to distinguish between seven isolates of cowdria ruminantium from geographically different areas. characteristic profiles were generated for each isolate by using the restriction endonucleases kspi, sali, and smai with chromosomal sizes ranging between 1,546 and 1,692 kb. statistical analysis of the macrorestriction profiles indicated that all the isolates were distinct from each other; these data contribute to ... | 2000 | 10790130 |
| competence of the african tortoise tick, amblyomma marmoreum (acari: ixodidae), as a vector of the agent of heartwater (cowdria ruminantium). | the ability of the african tortoise tick, amblyomma marmoreum, to acquire and transmit cowdria ruminantium infection was investigated experimentally with transmission trials and with a c. ruminantium-specific polymerase chain reaction (pcr) detection assay. laboratory-reared a. marmoreum larvae and nymphs were fed on small ruminants with clinical heartwater. after molting, the resultant nymphs were fed on cowdria ruminantium-naive sheep (n = 3), and the adults were ground and inoculated intraven ... | 2000 | 10864237 |
| monoclonal antibody binding to a surface-exposed epitope on cowdria ruminantium that is conserved among eight strains. | monoclonal antibodies (mab) binding to cowdria ruminantium elementary bodies (eb) were identified by enzyme-linked immunosorbent assay, and surface binding of one mab (446.15) to intact eb was determined by immunofluorescence, immunogold labeling, and transmission electron microscopy. mab 446.15 bound an antigen of approximately 43 kda in immunoblots of eight geographically distinct strains. the mab did not react with ehrlichia canis antigens or uninfected bovine endothelial cell lysate and may ... | 2000 | 11063511 |
| does geographic range affect the attractant-aggregation-attachment pheromone of the tropical bont tick, amblyomma variegatum? | the tropical bont tick, amblyomma variegatum, transmits heartwater in sub-saharan africa and in the caribbean. this species has a broad geographic distribution, ranging from madagascar and other islands in the indian ocean through most of sub-saharan africa, to several islands in the eastern caribbean sea. blood fed male a. variegatum secrete an attraction-aggregation-attachment (aaa) pheromone which, combined with co2, excites host finding and formation of feeding clusters of these ticks. howev ... | 2000 | 11110239 |
| feeding of hard ticks in vitro: new perspectives for rearing and for the identification of systemic acaricides. | experiments on in vitro feeding of the hard ticks ixodes ricinus, boophilus microplus, amblyomma variegatum and amblyomma hebraeum are described. an in vitro test for systemic acaricides is presented. work started with a feeding chamber continuously supplied with new blood. it proved too susceptible to fungal contamination and not efficient enough. simple feeding units made of honey jars with an inner glass tube were far more practical. reinforced silicone membrances or baudruche membrances impr ... | 1996 | 11178446 |
| [partly automated in vitro feeding of adult amblyomma hebraeum] | a reduction in the use of laboratory animals, such as rabbits and bovines, in the pharmaceutical industry and other institutions for breeding medically and economically important species of obligatory bloodsucking hard ticks (acari: ixodidae) is highly desirable. we report the successful feeding of males and females of the tropical tick amblyomma hebraeum in a partly automated, thus essentially maintenance-free in vitro system. the feeding data (body mass 1.85 degrees; egg conversion factor 0.37 ... | 1998 | 11178507 |
| eradication and surveillance of the tropical bont tick in the caribbean. an international approach. | the caribbean amblyomma program (cap) is a multidonor funded effort involving several technical organizations and national governments in the eradication of the tropical bont tick. the food and agriculture organization (fao) is the lead technical agency, providing both technical and administrative support to the cap regional coordination unit (rcu) based in barbados. all collaborating agencies, donors, and national representatives are members of the amblyomma program council (apc), the overall g ... | 2000 | 11193618 |
| tropical bont tick (amblyomma variegatum) eradication in the caribbean. the st. kitts experience. | the tropical bont tick (tbt) was first identified in st. kitts in 1978. initially, infestation was observed on cattle that developed a severe dermatitis. over a period of seven years, the tbt spread to most areas of the island, affecting cattle, sheep, and goats. the ruminant livestock population declined from, 6,000, 9,000, and 7,000 cattle, sheep, and goats, respectively, in 1984 to an estimated 400, 800, and 1,000, cattle, sheep, and goats in 1990. a project to control the tropical bont tick ... | 2000 | 11193641 |
| past and present national tick control programs. why they succeed or fail. | the historical reasons for the introduction of tick control during the nineteenth century are reviewed. background and concepts for the choice between long-term tick control and tick eradication are compared. case studies of large-scale tick control or eradication programs in africa, australia, the united states, and the caribbean are used to highlight successes and failures. the main reasons for lack of sustainability, or failure, of programs are discussed. these include the economic constraint ... | 2000 | 11193670 |
| ectoparasites of dogs belonging to people in resource-poor communities in north west province, south africa. | a total of 344 dogs belonging to people in resource-poor communities in north west province, south africa, was examined for ectoparasites, and all visible arthropods were collected from the left side of each dog. by doubling these numbers it was estimated that the dogs harboured 14,724 ixodid ticks, belonging to 6 species, 1,028 fleas, belonging to 2 species, and 26 lice. haemaphysalis leachi accounted for 420 and rhipicephalus sanguineus for 14,226 of the ticks. pure infestations of h. leachi w ... | 2000 | 11205167 |
| antibody responses to map 1b and other cowdria ruminantium antigens are down regulated in cattle challenged with tick-transmitted heartwater. | serological diagnosis of heartwater or cowdria ruminantium infection has been hampered by severe cross-reactions with antibody responses to related ehrlichial agents. a map 1b indirect enzyme-linked immunosorbent assay that has an improved specificity and sensitivity for detection of immunoglobulin g (igg) antibodies has been developed to overcome this constraint (a. h. m. van vliet, b. a. m. van der zeijst, e. camus, s. m. mahan, d. martinez, and f. jongejan, j. clin. microbiol. 33:2405-2410, 1 ... | 2001 | 11238227 |
| collection of free-living nymphs and adults of amblyomma hebraeum (acari: ixodidae) with pheromone/carbon dioxide traps at 5 different ecological sites in heartwater endemic regions of south africa. | the capture of free-living adults and nymphs of amblyomma hebraeum, the main vector of heartwater in domestic and wild ruminants in south africa, by means of attraction-aggregation-attachment-pheromone/carbon dioxide traps at five endemic localities in south africa is described. although the traps were used successfully at each of the localities, no determination of their efficiency in relation to the actual abundance of ticks at a particular site was made. this study confirmed that the traps co ... | 2000 | 11354624 |
| resistance of leopard tortoises and helmeted guineafowl to cowdria ruminantium infection (heartwater). | experimental infection trials were conducted to investigate susceptibility of leopard tortoises (geochelone pardalis) and helmeted guineafowl (numida meleagris) to infection with cowdria ruminantium, the causative agent of heartwater, a tickborne disease of domestic and wild ruminants. ten guineafowl were inoculated intravenously with a virulent dose of c. ruminantium derived from bovine endothelial cell cultures, and four leopard tortoises were exposed to c. ruminantium infection by the feeding ... | 2001 | 11423187 |
| 1-octen-3-ol isolated from bont ticks attracts amblyomma variegatum. | volatiles from various life-stages of the bont ticks amblyomma variegatum and a. hebraeum were collected by using solid-phase microfibers and charcoal traps. an octenol isomer was found to be a major constituent of most of the tick material sampled and was identified as 1-octen-3-ol by gas chromatography-mass spectrometry and by using antenna of the tsetse fly glossina brevipalpis in gas chromatography-linked antennogram detection. release of this compound increased during molt to adulthood and ... | 2001 | 11441439 |
| new distribution records of amblyomma hebraeum in the sandveld region of botswana. | | 2001 | 11563715 |
| parasites of domestic and wild animals in south africa. xl. ticks on dogs belonging to people in rural communities and carnivore ticks on the vegetation. | ixodid ticks were collected at weekly intervals from february 1999 to april 2000 from domestic dogs belonging to people in rural communities in north-eastern kwazulu-natal. seven ticks were identified to species level and adult haemaphysalis leachi followed by immature amblyomma hebraeum and adult rhipicephalus simus were the most prevalent. infestation with adult h. leachi was most intense during february and march 1999 and from january to april 2000, and least intense during october 1999. infe ... | 2001 | 11585091 |
| novel ehrlichia genotype detected in dogs in south africa. | dna samples from dogs presenting with symptoms suggestive of canine ehrlichiosis, but with no morulae detected on blood smears, frequently failed to give a positive reaction with a north american ehrlichia canis-specific pcr assay targeting the 16s rrna gene. we suspected the presence of a pathogen genetically different from north american e. canis, and we performed experiments to test this hypothesis. dna from one canine blood sample was subjected to pcr with primers designed to amplify ehrlich ... | 2001 | 11682562 |
| identification and characterization of genes differentially expressed in the testis/vas deferens of the fed male tick, amblyomma hebraeum. | most ixodid ticks must feed for at least a few days to complete gonad maturation. substances produced by the mature male gonad, and carried in the spermatophore, induce physiological changes in the female that lead to engorgement and oviposition. to begin defining the molecular phenotype at this stage of male development, we differentially cross-screened a cdna library made from the testis and vas deferens of fed ticks (amblyomma hebraeum koch) and isolated 35 genes that were putatively up-regul ... | 2002 | 12044495 |
| ixodid ticks on indigenous goats owned by small-scale farmers in four communal grazing areas in south africa. | indigenous goats belonging to small-scale farmers in 4 communal grazing areas in south africa were sampled for ixodid ticks during the period september 1991 to may 1993. three of these areas were in the north west province (rietgat, madinyane and bethany), and one in mpumalanga province (geluk). no tick control was practised unless requested by the owners. seven ixodid tick species, of which the majority were immature ticks, were collected from the goats in north west province. amblyomma hebraeu ... | 2002 | 12088070 |
| introduction of the exotic tick amblyomma hebraeum into florida on a human host. | a resident of florida returned from a short visit to southern africa to find a male amblyomma hebraeum tick attached to the skin behind her knee. amblyomma hebraeum is a major vector of 2 pathogens that cause important diseases in southern africa, heartwater of ruminants and african tick-bite fever of humans. the tick was tested by polymerase chain reaction assay for evidence of infection with cowdria ruminantium and rickettsia africae (the causative agents of heart-water and african tick-bite f ... | 2002 | 12197136 |
| attraction of the tropical bont tick, amblyomma variegatum, to human breath and to the breath components acetone, no and co2. | ticks are of medical and veterinary importance and employ several cues in search of a host. olfaction is one modality by which ticks locate a blood-meal and breath is the major vent of gaseous and volatile metabolites from the host that could contribute to this search. we studied the responses of a hunter tick, amblyomma variegatum, to diluted human breath and five of its components (acetone, co2, no, isoprene and nh3) while walking in an air stream on a locomotion compensator. diluted breath el ... | 2002 | 12216862 |
| amblyomma hebraeum is a vector of rickettsia africae and not r. conorii. | | 2001 | 12219911 |
| acaricide resistance profiles of single- and multi-host ticks from communal and commercial farming areas in the eastern cape and north-west provinces of south africa. | a field study (february 2000 to august 2001) was conducted on communal and commercial farms in the eastern cape and north-west provinces of south africa to detect the levels of tick resistance to commonly used acaricides. the larvae obtained from engorged females of the one-host tick boophilus decoloratus, the two-host tick rhipicepalus evertsi evertsi and the three-host ticks amblyomma hebraeum and rhipicephalus appendiculatus were tested against various concentrations of amitraz, chlorfenvinph ... | 2002 | 12234005 |
| eradication of the tropical bont tick in the caribbean: is the caribbean amblyomma program in a crisis? | the progress and problems in the caribbean amblyomma program (cap) are reviewed since its inception in 1995. during 1998, there were funding and administrative management problems. usda resolved the acute funding crisis, and after three years of negotiation, the cap has now secured an additional euro 1.5 million from the european community. changes in administration in 1998 included the withdrawal of iica from the program, and the transition during the decentralization of administrative and fina ... | 2002 | 12381609 |
| introduced ticks and tick-borne diseases: the threat and approaches to eradication. | exotic tick species and tick-borne diseases are serious threats to live-stock, companion animals, and wildlife in the united states. recurring introductions of exotic tick species into the united states are a significant indicator of the degree of risk. successful tick-eradication campaigns, such as the national program that eradicated boophilus annulatus and b. microplus from the united states, the cattle fever tick eradication program of the us department of agriculture's veterinary services t ... | 2002 | 12442574 |
| ixodid ticks on cattle belonging to small-scale farmers at 4 communal grazing areas in south africa. | ixodid ticks were collected during the period september 1991 to august 1993 from cattle belonging to small-scale farmers utilising 4 communal grazing areas. three of these were in north west province and 1 in mpumalanga province, south africa. ten tick species were collected in north west province and 7 in mpumalanga. the adults of amblyomma hebraeum, rhipicephalus appendiculatus and rhipicephalus evertsi evertsi were most numerous in north west province, while in mpumalanga boophilus decoloratu ... | 2002 | 12515294 |
| the prevalence of cowdria ruminantium in free-living adult amblyomma hebraeum collected at a communal grazing area and in 2 wildlife reserves in south africa. | in order to detect the prevalence of cowdria ruminantium in the vector tick, amblyomma hebraeum, free-living, unfed adult ticks were collected with the aid of pheromone/co2 traps. ticks were collected at the rietgat communal grazing area, as well as in the southwestern kruger national park and in the songimvelo game reserve, all located in heartwater-endemic areas of south africa. the presence of c. ruminantium in these ticks was determined by polymerase chain reaction (pcr) analysis. ticks from ... | 2002 | 12515301 |
| ixodid ticks feeding on humans in south africa: with notes on preferred hosts, geographic distribution, seasonal occurrence and transmission of pathogens. | this paper records the identities of 558 ixodid ticks feeding on 194 humans in south africa. these ticks belonged to 20 species in six genera and those most frequently encountered were amblyomma hebraeum, haemaphysalis leachi, hyalomma marginatum rufipes, hyalomma truncatum, rhipicephalus appendiculatus, rhipicephalus gertrudae and rhipicephalus simus. with the exception of the larvae of r. appendiculatus, the incidents of these ticks feeding on humans correlated well with their seasonal occurre ... | 2002 | 12593517 |
| repellent efficacy of deet and kbr 3023 against amblyomma hebraeum (acari: ixodidae). | the bont tick, amblyomma hebraeum koch, is the principal vector of rickettsia africae, the agent of african tick bite fever, in southern africa. in contrast to most other hard ticks, members of the genus amblyomma exhibit a characteristic attack host-seeking behavior. the efficacy of topically applied 20% lotions of deet (diethyl-3-methylbenzamide), the currently considered reference repellent substance, and kbr 3023, a recently developed piperidine compound, was evaluated against laboratory-rea ... | 2003 | 12693855 |
| quantification of vitellogenesis and its control by 20-hydroxyecdysone in the ixodid tick, amblyomma hebraeum. | ovaries of the ixodid tick, amblyomma hebraeum koch, grew rapidly after engorgment as a result of yolk uptake. at 26 degrees c, oviposition began by day 10 post-engorgement, plateaued on days 16-18, and ended by day 38. vitellin (vt) was partially purified from ovaries of day 10 engorged ticks by gel filtration and ion exchange chromatography. this vt comprises seven major and several minor polypeptides. two polypeptides (211 and 148 kd) from haemolymph of engorged female ticks corresponded to m ... | 2002 | 12770055 |
| the relationship between 'critical weight' and 20-hydroxyecdysone in the female ixodid tick, amblyomma hebraeum. | the feeding cycle of adult female ticks (acari: ixodidae) is divided into preparatory, slow and rapid feeding phases. at the transition from slow to rapid feeding, amblyomma hebraeum (koch) females reach a 'critical weight' (cw; approx. 10x the unfed weight) that is characterized by several behavioural and physiological changes. five of these changes were used as criteria to establish a more precise estimate of cw than we have to date. the cw as defined by re-attachment to the host was 9x the un ... | 2001 | 12770177 |
| seasonal fluctuation of parasitic infestation in donkeys (equus asinus) in oodi village, kgatleng district, botswana. | during the period march to september 2000, a study was conducted in oodi village, kgatleng district, botswana, to investigate the seasonal fluctuation of internal, external and blood parasites of donkeys. twelve adult donkeys were randomly selected from a farmer with a herd of 15 donkeys. monthly visits were made to the farmer when the donkeys were examined for parasites. the only ectoparasites recovered from the donkeys were instars of various tick species. the most prevalent tick was rhipiceph ... | 2003 | 12836744 |
| development of a polyclonal competitive enzyme-linked immunosorbent assay for detection of antibodies to ehrlichia ruminantium. | a polyclonal competitive enzyme-linked immunosorbent assay (pc-elisa) is described for detection of antibodies to ehrlichia (cowdria) ruminantium by using a soluble extract of endothelial cell culture-derived e. ruminantium as the antigen and biotin-labeled polyclonal goat immunoglobulins as the competitor. for goats, the diagnostic sensitivity and specificity were both 100% with a cutoff of 80% inhibition (80 pi), with detection of antibodies for 550 days postinfection. for cattle, diagnostic s ... | 2003 | 12965926 |
| climate change decreases habitat suitability for some tick species (acari: ixodidae) in south africa. | models predicting current habitat availability for four prominent tick species in africa (boophilus decoloratus, amblyomma hebraeum, rhipicephalus appendiculatus and hyalomma truncatum) were constructed using remotely sensed information about abiotic variables and a point-to-point similarity metric. year-to-year variations in the forecasted habitat suitability over the period 1983-2000 show a clear decrease in habitat availability, which is attributed primarily to increasing temperature in the r ... | 2003 | 12967169 |
| ixodid ticks of angora and boer goats, grysbok, common duikers, kudus and scrub hares in valley bushveld in the eastern cape province, south africa. | at monthly intervals from february 1983 to january 1984 two angora goats, two boer goats, one grysbok, raphicerus melanotis, one common duiker, sylvicapra grimmia, one greater kudu, tragelaphus strepsiceros, and four scrub hares, lepus saxatilis, were killed on a farm in valley bushveld in the eastern cape province, south africa and examined for ticks. seven ixodid tick species were collected, of which rhipicephalus glabroscutatum followed by amblyomma hebraeum and rhipicephalus oculatus were th ... | 2003 | 12967172 |
| parasites of domestic and wild animals in south africa. xli. arthropod parasites of impalas, aepyceros melampus, in the kruger national park. | ectoparasites were collected from impalas, aepyceros melampus, at four localities within the kruger national park, namely skukuza, in the biyamiti region, crocodile bridge and pafuri. animals were also examined at skukuza during a severe drought and at skukuza and pafuri towards the end of a second drought. parasite burdens were analysed in relation to locality, sex, age class, month and drought. the impalas were infested with 13 ixodid ticks species, including two that were identified only to g ... | 2003 | 12967174 |
| the bont tick (amblyomma hebraeum), exotic vector of heartwater found in the united states. | | 1965 | 14323370 |
| an inhibitor of thrombin-stimulated blood platelet aggregation from the salivary glands of the hard tick amblyomma variegatum (acari: ixodidae). | the tropical bont tick, amblyomma variegatum can cause intense skin irritation and inflammation and bites that often develop into septic wounds or abscess in their host. crude salivary gland extract (sge) of partially engorged a. variegatum females as well as sge protein fractions purified by three-step reverse phase hplc procedure were tested for their anti-aggregatory effect on isolated human blood platelets stimulated with thrombin and compared with the effect of recombinant hirudin. at conce ... | 2002 | 14570120 |
| progress towards the eradication of amblyomma variegatum from the caribbean. | progress in the caribbean amblyomma program (cap) is reviewed since its inception in 1995 when regional eradication activities for amblyomma variegatum ticks were initiated using bayticol pour-on. technical achievements in the various islands were slow initially, and showed a wide diversity in attaining eradication targets. st. kitts, considered as a model program. eliminated the tropical bont tick (tbt) from most of the island in less than 3 years. however, the elimination of very low numbers o ... | 2002 | 14570141 |
| attraction of amblyomma variegatum (ticks) to the attraction-aggregation-attachment-pheromone with or without carbon dioxide. | the responses of adult amblyomma variegatum ticks released from various distances to different doses of the synthetic attraction-aggregation-attachment pheromone (aaap) (made up of orthonitrophenol, methyl salicylate and nonanoic acid in paraffin oil), dispensed from the center of circular field plots, were studied in the presence or absence of elevated levels of co2. up to 90% of the ticks released were attracted to the pheromone source in the presence of co2 within 3h. co2 alone was unattracti ... | 2003 | 14580064 |
| comparing the detection of exposure to ehrlichia ruminantium infection on a heartwater-endemic farm by the pcs20 polymerase chain reaction assay and an indirect map1-b enzyme linked immunosorbent assay. | detection of heartwater is not always easy especially because all the serological assays so far available either have poor sensitivity or specificity. the indirect map-1b elisa has been reported to be the most specific test for heartwater, although it does also detect antibodies to some closely related ehrlichial agents. this study was undertaken to compare two methods for the detection of heartwater infection caused by the ehrlichial agent ehrlichia (cowdria) ruminantium. fifteen cattle on a he ... | 2003 | 14621319 |
| two novel non-cationic defensin-like antimicrobial peptides from haemolymph of the female tick, amblyomma hebraeum. | two non-cationic defensin-like antimicrobial peptides, named amblyomma defensin peptide 1 and amblyomma defensin peptide 2, were identified from the hard tick, amblyomma hebraeum, by a combination of suppression subtractive hybridization for differentially expressed genes and proteomics. cdna clones encoding each of these two defensin-like antimicrobial peptides were isolated from the differentially expressed cdna library of the tick synganglia (central nervous system). the preproproteins deduce ... | 2004 | 14705963 |
| two feeding-induced proteins from the male gonad trigger engorgement of the female tick amblyomma hebraeum. | most female ixodid ticks, once mated, feed to repletion within 6-10 days. previous studies indicate that an engorgement factor (ef), passed to the female during copulation, may be the stimulus for engorgement. here, we show that extracts of the testis/vas deferens of fed (but not unfed) male amblyomma hebraeum contain ef bioactivity when injected into the hemocoel of feeding virgins. we have produced recombinant proteins (recproteins) from 28 feeding-induced genes in the male gonad and have iden ... | 2004 | 15069191 |
| effects of 20-hydroxyecdysone and other hormones on egg development, and identification of a vitellin-binding protein in the ovary of the tick, amblyomma hebraeum. | partially fed adult female amblyomma hebraeum ticks were injected with 20-hydroxyecdysone (20e; up to 43 microg/g body weight (bw)), juvenile hormone iii (jh iii; up to 100 microg/g bw), bovine insulin (up to 2000 mu/g bw), or triiodothyronine (up to 200 ng/g bw) in an attempt to stimulate vitellogenesis. of these, only 20e stimulated synthesis and release of vitellogenin (vg). immunoblot analysis revealed that vg-synthesis occurred in the fat body. however, consistent with earlier observations ... | 2004 | 15183281 |
| development of a novel self-medicating applicator for control of internal and external parasites of wild and domestic animals. | four trials, three in the united states and one in south africa, were conducted to evaluate the potential value of a novel self-medicating applicator in the passive control of gastrointestinal nematodes in cattle and deer, and of files and ticks on cattle using oil-based treatments. the results of the trials demonstrated that this applicator is an effective and practical device for the passive treatment of both deer and cattle for trichostrongyle infections using the endectocide, moxidectin (cyd ... | 2004 | 15185574 |
| cross-reactivity between antigens from amblyomma cajennense and a. hebraeum (acari: ixodidae). | laboratory animals exposed to feeding ticks develop resistance which is reflected by a decline in tick engorgement weight, egg-laying by adults and reduced egg viability. serum antibodies from these hosts and their reaction with tick antigens have been detected by different methods, including precipitation techniques, immunofluorescent techniques, elisa and western blots. however, little is known about the effects of antibodies on ticks that engorge on resistant hosts, or which tissues of the ti ... | 2004 | 15214694 |
| a new type of antimicrobial protein with multiple histidines from the hard tick, amblyomma hebraeum. | a novel 11 kda antimicrobial protein, named as hebraein, and having a unique amino acid sequence, was purified from the hemolymph of fed female amblyomma hebraeum ticks. a full-length cdna clone encoding hebraein was isolated from a cdna library made from tick synganglia. hebraein consists of 102 amino acids, including 6 cysteine residues; has 9 histidines in its c-terminal domain that are mainly present as hx repeats; and has no significant similarity to any known protein. the secondary structu ... | 2004 | 15247144 |
| a thrombin inhibitor from the ixodid tick, amblyomma hebraeum. | a novel thrombin inhibitor named amblin was identified from the haemolymph of the ixodid (hard) tick, amblyomma hebraeum, and the coding cdna was isolated from a tick cdna library. this cdna codes for a preprotein of 166 amino acids, including a predicted signal peptide composed of 15 amino acids n-terminal to the mature amblin. the 151-amino-acid mature amblin contains 14 cysteines and two kunitz-like domains. it displays high sequence similarity with a tissue factor pathway inhibitor (tfpi), i ... | 2004 | 15527983 |
| the caribbean amblyomma program: some ecologic factors affecting its success. | the caribbean amblyomma program has been operational for 8 years. however, owing to funding availability, some islands did not commence eradication activities until late 1997. during the past 2 years, 6 of the 9 islands (st. kitts, st. lucia, anguilla, montserrat, barbados, and dominica) under the program have attained the status of provisional freedom from the tropical bont tick (tbt). there are several administrative and technical reasons why the attainment of the program goals took longer tha ... | 2004 | 15604510 |
| an attenuated ehrlichia ruminantium (welgevonden stock) vaccine protects small ruminants against virulent heartwater challenge. | heartwater is a tick-borne disease of ruminants caused by the intracellular rickettsia ehrlichia ruminantium. the only commercially available immunization procedure involves infecting animals with cryopreserved sheep blood containing virulent e. ruminantium organisms, followed by treatment with tetracyclines when fever develops. the virulent welgevonden stock of e. ruminantium was attenuated by continuous propagation of the organisms in a canine macrophage-monocyte cell line (dh82), followed by ... | 2005 | 15705474 |
| transstadial and intrastadial experimental transmission of ehrlichia canis by male rhipicephalus sanguineus. | the acquisition and transmission of rickettsial pathogens by different tick developmental stages has important epidemiological implications. the purpose of this study was to determine if male rhipicephalus sanguineus can experimentally acquire and transmit ehrlichia canis in the absence of female ticks. two trials were performed where nymphal and male r. sanguineus were simultaneously acquisition fed on the same infected donor hosts, and transstadially or intrastadially exposed male ticks were f ... | 2005 | 15941624 |
| repellent efficacy of four commercial deet lotions against amblyomma hebraeum (acari: ixodidae), the principal vector of rickettsia africae in southern africa. | african tick bite fever, caused by rickettsia africae, is an emerging zoonotic infection in rural sub-saharan africa and the french west indies. we tested the repellent efficacy of four commercial diethyl-3-methylbenzamide (deet) lotions against amblyomma hebraeum koch, the principal vector of r. africae in southern africa, by using a human bioassay in which repellent-treated fingers were presented to questing tick nymphs hourly for 4h. three lotions with 19.5, 31.6 and 80% deet concentrations, ... | 2005 | 15993907 |
| use of shell-vial cell culture assay for isolation of bacteria from clinical specimens: 13 years of experience. | the shell-vial culture assay is performed routinely in our laboratory. recently we revisited our experience of using the shell-vial culture assay for the isolation of microorganisms from various clinical samples. over a 13-year period, we have isolated 580 bacterial strains (5%) from 11,083 clinical samples tested. over the same period, 285 isolates of rickettsiae, bartonellae, or coxiella burnetii were cultured from a total of 7,102 samples tested. these isolates include 55 rickettsia sp. isola ... | 2005 | 16207953 |
| tick-borne rickettsioses around the world: emerging diseases challenging old concepts. | during most of the 20th century, the epidemiology of tick-borne rickettsioses could be summarized as the occurrence of a single pathogenic rickettsia on each continent. an element of this paradigm suggested that the many other characterized and noncharacterized rickettsiae isolated from ticks were not pathogenic to humans. in this context, it was considered that relatively few tick-borne rickettsiae caused human disease. this concept was modified extensively from 1984 through 2005 by the identif ... | 2005 | 16223955 |
| rickettsia africae in the west indies. | rickettsia africae is the agent of african tick-bite fever, a mild but common disease of local persons and tourists in africa. the major vector of this spotted fever group rickettsia is most likely amblyomma variegatum, the tropical bont tick, which has become widely distributed through the west indies in the last 30 years. this report reviews all available information on r. africae in the west indies. | 2006 | 16494746 |
| comparative genomic analysis of three strains of ehrlichia ruminantium reveals an active process of genome size plasticity. | ehrlichia ruminantium is the causative agent of heartwater, a major tick-borne disease of livestock in africa that has been introduced in the caribbean and is threatening to emerge and spread on the american mainland. we sequenced the complete genomes of two strains of e. ruminantium of differing phenotypes, strains gardel (erga; 1,499,920 bp), from the island of guadeloupe, and welgevonden (erwe; 1,512,977 bp), originating in south africa and maintained in guadeloupe in a different cell environ ... | 2006 | 16547041 |
| acaricide efficiency of amitraz/cypermethrin and abamectin pour-on preparations in game. | the efficacy of an amitraz/cypermethrin pour-on preparation (1% w/v each) was tested against natural tick infestations of buffaloes, eland and blesbok in three separate trials. the eland were also treated with a 0.02% abamectin (w/v) acaricidal pour-on preparation. the amitraz/cypermethrin pour-on was effective against amblyomma hebraeum, rhipicephalus evertsi evertsi, rhipicephalus appendiculatus and hyalomma marginatum rufipes on the buffaloes. both acaricides were effective against r. appendi ... | 2005 | 16562734 |
| ticks on crested francolins, francolinus sephaena, and on the vegetation on a farm in limpopo province, south africa. | ticks were collected at approximately bi-monthly intervals between june 1996 and june 1997 from crested francolins, francolinus sephaena, and from the vegetation on a mixed cattle and wildlife farm in limpopo province, south africa. the birds were infested with the immature stages of 13 tick species, of which amblyomma hebraeum, amblyomma marmoreum and hyalomma marginatum rufipes were the most numerous and prevalent. ten ixodid tick species were collected from the vegetation, of which the immatu ... | 2005 | 16562738 |
| the impact of 2 dipping systems on endemic stability to bovine babesiosis and anaplasmosis in cattle in 4 communally grazed areas in limpopo province, south africa. | a 12-month study was conducted in 4 communal grazing areas in the bushbuckridge region, limpopo province, south africa. the main objective was to investigate the impact of reduced acaricide application on endemic stability to bovine babesiosis (babesia bigemina and babesia bovis) and anaplasmosis (anaplasma marginale) in the local cattle population. to this end 60 cattle in each communal grazing area were bled at the beginning and the conclusion of the experimental period and their sera were ass ... | 2005 | 16642719 |
| pharmacological characterization of the ergot alkaloid receptor in the salivary gland of the ixodid tick amblyomma hebraeum. | female ticks of the family ixodidae osmoregulate by secreting the excess fluid of the blood meal back into the host's circulation via the salivary glands. at least three receptors control salivary fluid secretion in the tick amblyomma hebraeum: (1) dopamine (da) stimulates fluid secretion via a da receptor, (2) ergot alkaloids (eras) stimulate fluid secretion via an era-sensitive receptor (the natural ligand of which has not been identified), and (3) a gaba receptor potentiates the action of da ... | 2006 | 16788036 |
| antimicrobial activity in the egg wax of the african cattle tick amblyomma hebraeum (acari: ixodidae). | eggs of the tick amblyomma hebraeum koch (acari: ixodidae) inhibited the growth of escherichia coli and serratia marcescens (gram-negative bacteria) in solid culture, but not the growth of staphylococcus epidermidis, and only marginally the growth of bacillus subtilis (gram-positive bacteria). when egg wax was extracted with chloroform/methanol (2:1), the extract contained antibacterial activity, but the denuded eggs did not. when assayed against bacteria in liquid culture, the aqueous phase inh ... | 2006 | 16874555 |
| ticks (acari: ixodidae) associated with wildlife and vegetation of haller park along the kenyan coastline. | this artcile describes the results obtained from a tick survey conducted in haller park along the kenyan coastline. the survey aimed at evaluating tick-host associations, assessing tick population density, and providing baseline information for planning future tick control and management in the park. ticks (2,968) were collected by handpicking from eight species of wildlife and by dragging in 14 selected sites within the park. a considerable proportion of ticks were also collected from leaves, s ... | 2006 | 17017210 |
| molecular characterisation of camp-dependent protein kinase (pk-a) catalytic subunit isoforms in the male tick, amblyomma hebraeum. | the camp-dependent protein kinase (protein kinase a, pk-a) plays a central role in the regulation of diverse aspects of cellular activity. specifically, pk-a appears to play a key controlling role in the maturation of spermatids. using a pcr-based approach, with degenerate primers from the highly conserved regions of the pk-a catalytic (c) subunit in combination with 5' and 3' race, we have cloned three cdnas for the pk-a c-subunit of the male tick, amblyomma hebraeum. the three cdnas have open ... | 2006 | 17049629 |
| the use of a pour-on and spray dip containing amitraz to control ticks (acari: ixodidae) on cattle. | knockdown and persistence efficacies of a pour-on containing amitraz 1% and cypermethrin 1% and a spray dip containing 12.5% amitraz were compared. knock-down and persistence efficacies of the amitraz spray dip against rhipicephalus (boophilus) decoloratus and amblyomma hebraeum were significantly higher for the duration of the trial than those of the pour-on. in the case of rhipicephalus appediculatus and rhipicephalus evertsi evertsi, efficacy was significantly higher on days 2 and 5. resistan ... | 2006 | 17120621 |
| a survey of free-living ixodid ticks on a commercial game farm in the thabazimbi district, limpopo province, south africa. | free-living stages of ticks on a commercial game farm in the thabazimbi district, limpopo province, south africa, were collected by drag-sampling with flannel strips during the period september 2003 to august 2004. a total of 5 tick species was collected from 4 sites. boophilus decoloratus was the most abundant species, followed by amblyomma hebraeum. seasonal abundance of the ticks was quantified and an optimum time to implement control measures against the ticks is proposed. | 2006 | 17137055 |
| new tick defensin isoform and antimicrobial gene expression in response to rickettsia montanensis challenge. | recent studies aimed at elucidating the rickettsia-tick interaction have discovered that the spotted fever group rickettsia rickettsia montanensis, a relative of r. rickettsii, the etiologic agent of rocky mountain spotted fever, induces differential gene expression patterns in the ovaries of the hard tick dermacentor variabilis. here we describe a new defensin isoform, defensin-2, and the expression patterns of genes for three antimicrobials, defensin-1 (vsna1), defensin-2, and lysozyme, in the ... | 2007 | 17261604 |
| ixodid ticks on dogs in the eastern region of the eastern cape province, south africa. | the objective of this study was to determine the species composition and geographic distribution of ixodid ticks infesting domestic dogs in the eastern region of the eastern cape province. seventy-two communal cattle dip-tanks within this region were randomly selected as survey localities and their geographic coordinates recorded. in addition to ticks that were collected from five cattle and five goats at each of the dip-tanks, ticks were also collected from five dogs whenever possible. no dogs ... | 2006 | 17283731 |
| immunity against ixodes scapularis salivary proteins expressed within 24 hours of attachment thwarts tick feeding and impairs borrelia transmission. | in north america, the black-legged tick, ixodes scapularis, an obligate haematophagus arthropod, is a vector of several human pathogens including borrelia burgdorferi, the lyme disease agent. in this report, we show that the tick salivary gland transcriptome and proteome is dynamic and changes during the process of engorgement. we demonstrate, using a guinea pig model of i. scapularis feeding and b. burgdorferi transmission, that immunity directed against salivary proteins expressed in the first ... | 2007 | 17505544 |
| tissue and life-stage distribution of a defensin gene in the lone star tick, amblyomma americanum. | the transcript sequence of the amblyomma americanum linnaeus (acari: ixodidae) defensin, termed amercin (amn), was ascertained and a 219-bp amn coding region identified. the gene encodes a 72-amino acid prepropeptide with a putative 37-amino acid mature peptide. this gene shows little similarity to either of the defensins from amblyomma hebraeum koch, the only other amblyomma species for which a defensin has been described. sequence comparisons with other tick defensins reveal amn to be shorter ... | 2007 | 17550433 |
| brasiliensin: a novel intestinal thrombin inhibitor from triatoma brasiliensis (hemiptera: reduviidae) with an important role in blood intake. | every hematophagous invertebrate studied to date produces at least one inhibitor of coagulation. among these, thrombin inhibitors have most frequently been isolated. in order to study the thrombin inhibitor from triatoma brasiliensis and its biological significance for the bug, we sequenced the corresponding gene and evaluated its biological function. the t. brasiliensis intestinal thrombin inhibitor, termed brasiliensin, was sequenced and primers were designed to synthesize double strand rna (d ... | 2007 | 17575982 |
| longitudinal monitoring of ehrlichia ruminantium infection in gambian lambs and kids by pcs20 pcr and map1-b elisa. | the epidemiology of e. ruminantium infection in extensively managed young animals is not adequately understood. thus in this study, we monitored the onset (age at first infection) and kinetics of e. ruminantium infection and antibody response in extensively managed newborn lambs and kids at three sites in the gambia. | 2007 | 17662144 |
| detection of "rickettsia sp. strain uilenbergi" and "rickettsia sp. strain davousti" in amblyomma tholloni ticks from elephants in africa. | to date, 6 tick-borne rickettsiae pathogenic for humans are known to occur in africa and 4 of them were first identified in ticks before being recognized as human pathogens. | 2007 | 17683629 |
| variegin, a novel fast and tight binding thrombin inhibitor from the tropical bont tick. | tick saliva contains potent antihemostatic molecules that help ticks obtain their enormous blood meal during prolonged feeding. we isolated thrombin inhibitors present in the salivary gland extract from partially fed female amblyomma variegatum, the tropical bont tick, and characterized the most potent, variegin, one of the smallest (32 residues) thrombin inhibitors found in nature. full-length variegin and two truncated variants were chemically synthesized. despite its small size and flexible s ... | 2007 | 17684009 |
| detection of rickettsia africae in rhipicephalus (boophilus) decoloratus ticks from the republic of botswana, south africa. | a total of 53 engorged adult ticks belonging to the species rhipicephalus (boophilus) decoloratus (n = 9), rhipicephalus evertsi evertsi (n = 27), rhipicephalus appendiculatus (n = 9), amblyomma hebraeum (n = 5), and hyalomma marginatum turanicum (n = 3), were removed from oryx in botswana (south africa). they were tested for the presence of spotted fever group (sfg) rickettsia and anaplasma phagocytophilum using polymerase chain reaction (pcr). seventy-seven percent of r. decoloratus as well as ... | 2007 | 17690416 |
| goats as alternative hosts of cattle ticks. | the objective of this study was to compare the presence on goats and cattle of adult ticks that usually infest cattle. to this end ticks collected from sets of five goats were compared with those collected from sets of five cattle at 72 communal dip-tanks in the eastern region of the eastern cape province. amblyomma hebraeum was present on goats at 25 and on cattle at 39 dip-tanks, and a total of 61 goats and 138 cattle were infested. adult rhipicephalus (boophilus) microplus was present on goat ... | 2007 | 17708147 |
| ticks associated with the three largest wild ruminant species in southern africa. | the objective of this study was to assess the host status of the three largest southern african wild ruminants, namely giraffes, giraffa camelopardalis, african buffaloes, syncerus caffer, and eland, taurotragus oryx for ixodid ticks. to this end recently acquired unpublished data are added here to already published findings on the tick burdens of these animals, and the total numbers and species of ticks recorded on 12 giraffes, 18 buffaloes and 36 eland are summarized and discussed. twenty-eigh ... | 2007 | 17933365 |
| an insight into the sialome of the soft tick, ornithodorus parkeri. | while hard ticks (ixodidae) take several days to feed on their hosts, soft ticks (argasidae) feed faster, usually taking less than 1h per meal. saliva assists in the feeding process by providing a cocktail of anti-hemostatic, anti-inflammatory and immunomodullatory compounds. saliva of hard ticks has been shown to contain several families of genes each having multiple members, while those of soft ticks are relatively unexplored. analysis of the salivary transcriptome of the soft tick ornithodoru ... | 2008 | 18070662 |
| comparative sialomics between hard and soft ticks: implications for the evolution of blood-feeding behavior. | ticks evolved various mechanisms to modulate their host's hemostatic and immune defenses. differences in the anti-hemostatic repertoires suggest that hard and soft ticks evolved anti-hemostatic mechanisms independently, but raise questions on the conservation of salivary gland proteins in the ancestral tick lineage. to address this issue, the sialome (salivary gland secretory proteome) from the soft tick, argas monolakensis, was determined by proteomic analysis and cdna library construction of s ... | 2008 | 18070664 |
| climate changes and suitability for the ticks amblyomma hebraeum and amblyomma variegatum (ixodidae) in zimbabwe (1974-1999). | the spread of amblyomma hebraeum has been reported in zimbabwe. at the same time there was little or no spread in the distribution of amblyomma variegatum. this paper examines the climatic cycles and their trends in the period 1974-1999 with a view to explaining the abiotic causes of this spread, and of forecasting the likely tendency in climate suitability for both tick species. an annual data-set of rainfall and air temperature was used as a source for climate, together with a habitat-modeling ... | 2008 | 18083309 |
| identity and transfer of male reproductive gland proteins of the dengue vector mosquito, aedes aegypti: potential tools for control of female feeding and reproduction. | male reproductive gland proteins (mrgps) impact the physiology and/or behavior of mated females in a broad range of organisms. we sought to identify mrgps of the yellow fever mosquito, aedes aegypti, the primary vector of dengue and yellow fever viruses. earlier studies with ae. aegypti demonstrated that "matrone" (a partially purified male reproductive accessory gland substance) or male accessory gland fluid injected into virgin female ae. aegypti affect female sexual refractoriness, blood feed ... | 2008 | 18207079 |
| isolation, cloning and structural characterisation of boophilin, a multifunctional kunitz-type proteinase inhibitor from the cattle tick. | inhibitors of coagulation factors from blood-feeding animals display a wide variety of structural motifs and inhibition mechanisms. we have isolated a novel inhibitor from the cattle tick boophilus microplus, one of the most widespread parasites of farm animals. the inhibitor, which we have termed boophilin, has been cloned and overexpressed in escherichia coli. mature boophilin is composed of two canonical kunitz-type domains, and inhibits not only the major procoagulant enzyme, thrombin, but i ... | 2008 | 18286181 |
| prevention of infectious tick-borne diseases in humans: comparative studies of the repellency of different dodecanoic acid-formulations against ixodes ricinus ticks (acari: ixodidae). | abstract: | 2008 | 18397516 |
| cellular and molecular characterization of an embryonic cell line (bme26) from the tick rhipicephalus (boophilus) microplus. | the cellular and molecular characteristics of a cell line (bme26) derived from embryos of the cattle tick rhipicephalus (boophilus) microplus were studied. the cells contained glycogen inclusions, numerous mitochondria, and vesicles with heterogeneous electron densities dispersed throughout the cytoplasm. vesicles contained lipids and sequestered palladium meso-porphyrin (pd-mp) and rhodamine-hemoglobin, suggesting their involvement in the autophagic and endocytic pathways. the cells phagocytose ... | 2008 | 18405834 |
| amblyomma variegatum in cattle in marie galante, french antilles: prevalence, control measures, and infection by ehrlichia ruminantium. | we report marie galante as one of the caribbean islands most heavily infested by the tropical bont tick (tbt) amblyomma variegatum which is associated with two major diseases of ruminants: heartwater and dermatophilosis. in 2005, a survey was undertaken to assess the prevalence of tbt infestation in cattle, the prevalence of ehrlichia ruminantium infection in tbts, and the tick control measures implemented by livestock owners. a random sample of 195 cattle herds out of 1885 recorded on the islan ... | 2008 | 18406061 |
| a quantitative real-time pcr assay for ehrlichia ruminantium using pcs20. | heartwater is a tick borne disease that affects ruminants and wild animals in africa south of the sahara. it is caused by ehrlichia ruminantium and transmitted by the tick amblyomma hebraeum. the protocols currently used to detect heartwater take several days to complete. here, we describe the development of a pcs20 quantitative real-time pcr taqman probe assay to detect e. ruminantium in livestock blood and ticks from the field. the assay is based on the conserved pcs20 gene region of e. rumina ... | 2008 | 18511221 |
| identification of two genes essential for sperm development in the male tick amblyomma hebraeum koch (acari: ixodidae). | in most ticks of the family ixodidae, gonad maturation and spermatogenesis are stimulated by the taking of a blood meal. previous work from this laboratory identified 35 genes that are up-regulated by feeding [weiss, b.l., stepczynski, j.m., wong, p., kaufman, w.r., 2002. identification and characterization of genes differentially expressed in the testis/vas deferens of the fed male tick, amblyomma hebraeum. insect biochemistry and molecular biology 32, 785-793]. the functions of most of these g ... | 2008 | 18549958 |
| climate extremes promote fatal co-infections during canine distemper epidemics in african lions. | extreme climatic conditions may alter historic host-pathogen relationships and synchronize the temporal and spatial convergence of multiple infectious agents, triggering epidemics with far greater mortality than those due to single pathogens. here we present the first data to clearly illustrate how climate extremes can promote a complex interplay between epidemic and endemic pathogens that are normally tolerated in isolation, but with co-infection, result in catastrophic mortality. a 1994 canine ... | 2008 | 18575601 |
| effect of 20-hydroxyecdysone and haemolymph on oogenesis in the ixodid tick amblyomma hebraeum. | earlier work from our laboratory indicated that injection of 20-hydroxyecdysone (20e) into non-vitellogenic female amblyomma hebraeum ticks stimulates the synthesis of vitellogenin (vg), but not its uptake into oocytes [friesen, k., kaufman, w.r., 2004. effects of 20-hydroxyecdysone and other hormones on egg development, and identification of a vitellin-binding protein in the ovary of the tick, amblyomma hebraeum. journal of insect physiology 50, 519-529]. in contrast, thompson et al. [thompson, ... | 2008 | 18634796 |
| an insight into the salivary transcriptome and proteome of the soft tick and vector of epizootic bovine abortion, ornithodoros coriaceus. | the salivary glands of blood-sucking arthropods contain a redundant 'magic potion' that counteracts their vertebrate host's hemostasis, inflammation, and immunity. we here describe the salivary transcriptome and proteomics (sialome) of the soft tick ornithodoros coriaceus. the resulting analysis helps to consolidate the classification of common proteins found in both soft and hard ticks, such as the lipocalins, kunitz, cystatin, basic tail, hebraein, defensin, til domain, metalloprotease, 5'-nuc ... | 2008 | 18725333 |
| the impact of rna interference of the subolesin and voraxin genes in male amblyomma hebraeum (acari: ixodidae) on female engorgement and oviposition. | reducing or replacing the use of chemical pesticides for tick control is a desirable goal. the most promising approach would be to develop vaccines that protect hosts against tick infestation. antigens suitable for the development of anti-tick vaccines will likely be those essential for vital physiological processes, and in particular those directly involved in feeding and reproduction. in this study genes from amblyomma hebraeum koch that encode for subolesin and voraxin were studied in male ti ... | 2009 | 18830675 |
| host surveys, ixodid tick biology and transmission scenarios as related to the tick-borne pathogen, ehrlichia canis. | the ehrlichioses have been subject to increasing interest from veterinary and public health perspectives, but experimental studies of these diseases and their etiologic agents can be challenging. ehrlichia canis, the primary etiologic agent of canine monocytic ehrlichiosis, is relatively well characterized and offers unique advantages and opportunities to study interactions between a monocytotropic pathogen and both its vertebrate and invertebrate hosts. historically, advances in tick-borne dise ... | 2008 | 18963493 |