| comparison of the attachment rates of males of the ticks amblyomma hebraeum and a. variegatum to cattle, sheep and rabbits in the absence of aggregation-attachment pheromone. | losses in domestic ruminants caused by heartwater (cowdria ruminantium infection) in zimbabwe and mozambique are greater when the vector is amblyomma hebraeum than when the vector is a. variegatum. it has been suggested that the epidemiology of the disease may be influenced by the rates at which unfed adults of these two tick species attach to uninfested hosts (i.e. in the absence of the male-produced aggregation-attachment pheromone [aap]). in this study we confined unfed males of a. hebraeum a ... | 1992 | 1446569 |
| adult amblyomma hebraeum burdens and heartwater endemic stability in cattle. | several conclusions of importance to studies on the epidemiology of heartwater were drawn from an investigation in which the numbers of adult amblyomma hebraeum ticks, to which a closed herd of hereford cattle were exposed over a period of 6 1/2 years, were manipulated. with a tick cowdria ruminantium infection rate of 3-5%, an endemically stable situation was created by dipping the herd only when an average of 10 adult male and female a. hebraeum ticks were counted on 10 animals. when the avera ... | 1992 | 1513597 |
| resistance of indigenous african cattle to the tick amblyomma hebraeum. | field collections of amblyomma hebraeum koch adults from six breeds of cattle were conducted on two farms in the northern transvaal. the density of a. hebraeum adults was highest on simmentaler cows, followed by santa gertrudis, africaner, bonsmara, brahman and nguni. indigenous breeds, namely nguni, bonsmara and africaner, have the highest level of resistance to a. hebraeum. the relationship between tick abundance and the high level of resistance found in the indigenous breeds is discussed. | 1991 | 1773680 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| pheromone-mediation of host-selection in bont ticks (amblyomma hebraeum koch). | the bont tick, amblyomma hebraeum, is the principal vector to southern african ruminants of heartwater (cowdria ruminantium infection). the role of feeding male ticks, which emit an aggregation-attachment pheromone, in attracting unfed ticks to cattle was investigated. calves infested with feeding male ticks were more attractive to unfed adult ticks than were uninfested calves. the presence of the pheromone on previously infested cattle apparently allows unfed ticks to discriminate between hosts ... | 1989 | 2911745 |
| field sampling of unfed adults of amblyomma hebraeum koch. | no methods have previously been available for the field sampling of unfed adults of amblyomma hebraeum. we released 2000 unfed adults into a 5-m2 area in mopane woodland in southeastern zimbabwe. the ticks sought shelter beneath the debris on the soil surface but emerged and became active in host seeking when stimulated. effective stimuli were the odours of cattle and sheep and high concentrations of carbon dioxide from dry ice. the ticks did not respond to low concentrations of carbon dioxide, ... | 1987 | 3135161 |
| control of induced infestations of adult amblyomma hebraeum with sustained release ivermectin. | the efficacy of ivermectin, administered in a sustained release formulation by intraruminal pumps at approximate daily dose rates of 20, 40 and 60 micrograms/kg, was evaluated in 16 cattle against induced infestations of 3 strains of adult amblyomma hebraeum. engorged female ticks were mass-measured and incubated, and reproductive data recorded. there was an increase in mortality of male and female ticks compared to that of controls with increasing daily dose of ivermectin, and a decrease in the ... | 1987 | 3295646 |
| heartwater. the artificial transmission of cowdria ruminantium in domestic ruminants and mice. | the artificial transmission of cowdria ruminantium with infected blood, organ homogenates, peritoneal macrophages, tick stabilate and tissue culture cells is discussed. organ homogenates prepared from the myocardium, spleen, kidneys and liver of diseased animals are commonly used to infect mice. the efficacy of organ homogenates as a source of c. ruminantium depends on factors such as the route of inoculation and the heartwater isolate used. heartwater is artificially transmitted with infected t ... | 1987 | 3329318 |
| some avian and mammalian hosts of amblyomma hebraeum and amblyomma marmoreum (acari: ixodidae). | large numbers of birds, wild mammals and domestic stock from a variety of localities within the republic of south africa were examined for infestation with the ixodid ticks amblyomma hebraeum and amblyomma marmoreum. every warthog (phacochoerus aethiopicus), burchell's zebra (equus burchelli), impala (aepyceros melampus) and kudu (tragelaphus strepsiceros) from the kruger national park in the north-eastern transvaal lowveld was infested with a. hebraeum. in the eastern cape province every helmet ... | 1987 | 3329327 |
| problems with the interpretation of epidemiological data in heartwater: a study on 23 farms. | in an epidemiological study undertaken on 23 farms where heartwater occurs endemically, it was found that on an overall average, antibodies to cowdria ruminantium were detected in 64.3% of the cattle, 6 adult amblyomma hebraeum ticks were counted per animal and 7.0% of ticks were infected with the heartwater agent. it was found that the seropositivity of the animals was determined largely by the tick loads to which they were subjected and that the influence of the tick c. ruminantium infection r ... | 1987 | 3448573 |
| the use of flumethrin 1% pour-on for the control of amblyomma spp. in various southern african countries. | efficacy trials with flumethrin 1% pour-on were conducted in 9 different areas in 3 southern and central african countries against amblyomma hebraeum and a. variegatum on cattle. a dose volume of 10 ml/100 kg body mass applied at bi-weekly intervals provided excellent control of both tick species on their predilection sites, irrespective of locally and seasonally high tick pressure. the trial results demonstrate clearly that this new concept of tick control can be effectively applied in commerci ... | 1987 | 3448582 |
| a comparison of the tick burdens of wild animals in a nature reserve and on an adjacent farm where tick control is practised. | acaricidal treatment of cattle, sheep and goats on a farm in valley bushveld in the grahamstown district resulted in a reduction in the numbers of certain tick species on kudu (tragelaphus strepsiceros), scrub hares (lepus saxatilis) and crowned guinea fowl (numida meleagris) on the same farm. the tick species most severely affected was amblyomma hebraeum, while haemaphysalis silacea, hyalomma marginatum rufipes and rhipicephalus appendiculatus were affected to a lesser extent. rhipicephalus gla ... | 1986 | 3572954 |
| protection of cattle against heartwater in botswana: comparative efficacy of different methods against natural and blood-derived challenges. | five groups of tswana-cross castrated male cattle between 20 and 30 months of age (a total of 158 animals) were transported from a ranch in a heartwater-free area of south botswana to a feedlot near gaborone in the east of botswana where heartwater is endemic. on arrival, one group was vaccinated intravenously with the onderstepoort sheep blood heartwater vaccine, one group was vaccinated intravenously with the new onderstepoort tick-derived heartwater vaccine and a third group was vaccinated su ... | 1987 | 3604029 |
| a method for determining the cowdria ruminantium infection rate of amblyomma hebraeum: effects in mice injected with tick homogenates. | amblyomma hebraeum ticks, collected in the field and individually homogenized, were injected into mice. thirteen out of 240 ticks were shown to be infected with the heartwater agent. antibodies against cowdria ruminantium were detected in the sera of the mice by means of the indirect fluorescent antibody test. giemsa-stained smears, prepared from the haemocytes of the ticks, revealed morphologically different forms of the heartwater agent. a strain of c. ruminantium, designated the welgevonden s ... | 1985 | 3900855 |
| observations on the transmission of theileria mutans in south africa. | four isolates of theileria mutans obtained from geographically distant parts of south africa by subinoculation of infected blood were found to be readily transmitted by the bont tick amblyomma hebraeum. all attempts to transmit these isolates with rhipicephalus appendiculatus were unsuccessful. possible explanations for differences between these results and those reported by earlier workers in this country are discussed. | 1981 | 6792579 |
| the detection of antibodies cross-reacting with cowdria ruminantium in the sera of domestic ruminants in regions of south africa where amblyomma hebraeum does not occur. | high levels of seropositivity, in all probability attributable to ehrlichia, were recorded in the serum of domestic ruminants throughout districts in south africa where amblyomma hebraeum, the vector of the heartwater agent, does not occur. the antibodies, detected with the indirect fluorescent antibody (ifa) and the indirect elisa tests, cross-reacted with cowdria ruminantium, which was used as antigen in both tests. a combination of the ifa and elisa tests, currently employed to detect antibod ... | 1994 | 7501358 |
| effects of tick infestation and tick-borne disease infections (heartwater, anaplasmosis and babesiosis) on the lactation and weight gain of mashona cattle in south-eastern zimbabwe. | the effects of ticks and tick-borne disease infections on the lactation and weight gain of mashona cattle were studied at mbizi quarantine station in the south-eastern lowveld of zimbabwe. twenty-nine mashona cows were allocated to 2 balanced groups and kept in separate paddocks at a stocking rate of one animal per 8 ha. one group received regular acaricide treatment to control bont (amblyomma hebraeum) and other ticks. the other group was left untreated. the cows were artificially inseminated. ... | 1995 | 7502343 |
| factors affecting the distributions of the ticks amblyomma hebraeum and a. variegatum in zimbabwe: implications of reduced acaricide usage. | the ticks amblyomma hebraeum and a. variegatum are the main vectors of heartwater, a disease of ruminants caused by cowdria ruminantium, in the agricultural areas of zimbabwe. at present, a. hebraeum is widely distributed in the dry southern lowveld, and occurs in at least seven foci in the higher rainfall highveld. amblyomma variegatum occurs in the zambezi valley and surrounding dry lowveld areas in the northwest. the distribution of a. hebraeum has changed considerably over the past 70 years, ... | 1994 | 7628253 |
| development and evaluation of pcr assay for detection of low levels of cowdria ruminantium infection in amblyomma ticks not detected by dna probe. | the sensitivities of a pcr assay and a dna probe assay were compared for the detection of cowdria ruminantium in amblyomma ticks that were fed on c. ruminantium-infected, clinically reacting, and recovered carrier animals. the pcr assay and dna probe detected infection in 86.0 and 37.0%, respectively, of 100 ticks fed on a febrile animal. in 75 ticks fed on carrier animals, pcr and the dna probe detected infection in 28.0 and 1.33% of ticks, respectively. this demonstrates that the dna probe has ... | 1995 | 7699036 |
| antibodies to cowdria ruminantium in mozambican goats and cattle detected by immunofluorescence using endothelial cell culture antigen. | endothelial cell cultures, established from bovine umbilical cord arteries and subsequently infected with cowdria ruminantium, were used as antigen in the indirect fluorescent antibody test. bovine sera (374) and caprine sera (388) collected in 6 provinces of mozambique were tested. overall, 30.4% of goat sera had antibodies to cowdria, and 43% of sera collected from cattle. north of the river save, where the tick amblyomma variegatum is highly prevalent, overall percentages of positive sera wer ... | 1993 | 8236490 |
| an immunoblotting diagnostic assay for heartwater based on the immunodominant 32-kilodalton protein of cowdria ruminantium detects false positives in field sera. | heartwater, a major constraint to improved livestock production in zimbabwe, threatens to invade areas which have been previously unaffected. to monitor its spread in zimbabwe, an immunoblotting diagnostic assay based on the responses of animals to the immunodominant, conserved 32-kda protein of cowdria ruminantium was evaluated. in this assay, no false reactions were detected with sera known to be positive and negative, but sera from some cattle, sheep, and goats from heartwater-free areas of z ... | 1993 | 8253974 |
| the relationship between tick (amblyomma hebraeum) infestation and immunity to heartwater (cowdria ruminantium infection) in calves in zimbabwe. | the occurrence of endemic stability for heartwater (cowdria ruminantium infection) is a controversial issue, because the means by which young cattle and other neonatal ruminants become infected and acquire immunity to the disease have never been adequately explained. we conducted a study in a heartwater-endemic area in southeastern zimbabwe to investigate the relationships between calf immunity to c. ruminatium, infestations of the tick vector amblyomma hebraeum and dam, colostral and calf antib ... | 1995 | 8533273 |
| parasites of domestic and wild animals in south africa. xxxiii. ixodid ticks on scrub hares in the north-eastern regions of northern and eastern transvaal and of kwazulu-natal. | ixodid ticks were collected from scrub hares (lepus saxatilis) at three localities. nine tick species were recovered from 24 hares examined at pafuri, kruger national park, northern transvaal. the most abundant and prevalent species were hyalomma truncatum, rhipicephalus kochi and a rhipicephalus species (near r. pravus). twelve tick species were collected from 120 scrub hares examined around skukuza, kruger national park, eastern transvaal. the immature stages of hyalomma truncatum were most ab ... | 1995 | 8600436 |
| investigation of tick-borne viruses as pathogens of humans in south africa and evidence of dugbe virus infection in a patient with prolonged thrombocytopenia. | in the course of investigating suspected cases of viral haemorrhagic fever in south africa patients were encountered who had been bitten by ticks, but who lacked evidence of infection with crimean-congo haemorrhagic fever (cchf) virus or non-viral tick-borne agents. cattle sera were tested by enzyme-linked immunoassay to determine whether tick-borne viruses other than cchf occur in the country. the prevalence of antibody in cattle sera was 905/2116 (42.8%) for cchf virus, 70/1358 (5.2%) for dugb ... | 1996 | 8666081 |
| efficacy of pheromone-acaricide-impregnated tail-tag decoys for controlling the bont tick, amblyomma hebraeum (acari: ixodidae), on cattle in zimbabwe. | a large-scale field test using pheromone-acaricide-impregnated plastic tail-tag decoys demonstrated excellent efficacy of these devices for control of the bont tick, amblyomma hebraeum, on cattle in zimbabwe. the tail tags were impregnated with a mixture containing o-nitrophenol, methyl salicylate, 2,6-dichlorophenol and phenylacetaldehyde and one of three different acaricides (cyfluthrin, flumethrin or alphacypermethrin). o-nitrophenol and methyl salicylate are components of the a. hebraeum att ... | 1996 | 8746132 |
| infestations of the bont tick amblyomma hebraeum (acari: ixodidae) on different breeds of cattle in zimbabwe. | infestations of adults and nymphs of amblyomma hebraeum were counted on brahman (br), brahman x simmental (bs), sanga (sa) and hereford (he) steers exposed to infested pastures at mbizi in southern zimbabwe in 1986-1987. herefords were always the most heavily infested, while the sanga tended to carry the fewest ticks with the brahman and brahman x simmental groups being in between. the ratios of the engorged females on the four breeds were 2.3:1.4:1.4:1.0 for he:br:bs:sa. the ratios of the stand ... | 1996 | 8952073 |
| the possible role of two common three-host ticks, rhipicephalus appendiculatus and amblyomma hebraeum, in the transmission of bovine leukosis virus. | the possible role of rhipicephalus appendiculatus and amblyomma hebraeum in the mechanical and transstadial transmission of bovine leukosis virus (blv) was investigated. blv-free laboratory strains of r. appendiculatus and a. hebraeum nymphal ticks (n = 400) were fed on a blv-infected and a negative control bovine. at various intervals after engorgement the ticks were homogenised and injected subcutaneously into blv-negative sheep. adult r. appendiculatus and a. hebraeum, which had fed as nymphs ... | 1996 | 9120860 |
| the effects of the bont tick, amblyomma hebraeum, on milk production of sanga and sanga x brahman cattle. | the effects of adults on the bont tick, amblyomma hebraeum on the milk production of sanga and sanga x zebu (brahman) cattle were measured over a period of 11 weeks in the low veld of zimbabwe in the summer of 1986. four groups of lactating cows, consisting of two breeds, each divided into a high and low tick treatment, were exposed to very low or high challenges of ticks and their milk production measured by weighing their calves before and after suckling. the liveweight gains (lwg) of the calv ... | 1997 | 9226643 |
| immunization of cattle by infection with cowdria ruminantium elicits t lymphocytes that recognize autologous, infected endothelial cells and monocytes. | peripheral blood mononuclear cells (pbmc) from immune cattle proliferate in the presence of autologous cowdria ruminantium-infected endothelial cells and monocytes. endothelial cells required treatment with t-cell growth factors to induce class ii major histocompatibility complex expression prior to infection and use as stimulators. proliferative responses to both infected autologous endothelial cells and monocytes were characterized by expansion of a mixture of cd4+, cd8+, and gammadelta t cell ... | 1998 | 9573061 |
| pcr detection of cowdria ruminantium infection in ticks and animals from heartwater-endemic regions of zimbabwe. | the development of a pcr assay for the detection of cowdria ruminantium infection in ticks has been previously described. here we report a further evaluation of this assay by comparison with a dna probe and with the mouse inoculation assay (mia). application of the pcr assay in determining the prevalence of infection in ruminants and ticks from heartwater-endemic areas of zimbabwe is also described. one hundred uninfected and 120 infected amblyomma hebraeum ticks were analyzed by pcr, dna probe ... | 1998 | 9668453 |
| investigating the epidemiology of heartwater (cowdria ruminantium infection) by means of a transmission dynamics model. | a mathematical model of the transmission dynamics of cowdria ruminantium by the ixodid tick amblyomma hebraeum in the bovine host is developed and used to investigate the epidemiology of heartwater across a range of vector challenge. the processes described are supported by empirical data. the pattern of outcome measures (incidence, case-fatality and proportion of infected hosts) predicted agrees with those described anecdotally from field experience and empirical observation, and demonstrates t ... | 1998 | 9695100 |
| the distribution of heartwater in the highveld of zimbabwe, 1980-1997. | heartwater, the tick-borne disease caused by the rickettsia cowdria ruminantium has historically been confined to the southern and western lowvelds of zimbabwe. since 1986, however, cases of heartwater have been diagnosed with increasing frequency in the central and eastern regions of the previously heartwater-free highveld plateau. during the same period, collections of the two major tick vectors of heartwater in zimbabwe, amblyomma hebraeum and amblyomma variegatum, were made for the first tim ... | 1998 | 9809322 |
| comment on "a possible explanation of the apparent breed-related resistance in cattle to bont tick (amblyomma hebraeum) infestations" by m.i. meltzer, veterinary parasitology 67 (1996) 275-279. | | 1998 | 9823067 |
| distributions of the vectors of heartwater, amblyomma hebraeum and amblyomma variegatum (acari: ixodidae), in zimbabwe. | the tick vectors of heartwater (cowdria ruminantium infection) in zimbabwe, amblyomma hebraeum and amblyomma variegatum, historically were believed to be confined to the low-lying regions of the south and north-west of the country. however, country-wide surveys performed in 1975-1980 and 1988-1991 demonstrated that both species were also established in western parts of the highveld plateau and had started to encroach on the predominantly heartwater-free central and eastern highveld regions. to d ... | 1998 | 10030008 |
| restriction of major surface protein 2 (msp2) variants during tick transmission of the ehrlichia anaplasma marginale. | anaplasma marginale is an ehrlichial pathogen of cattle that establishes lifelong persistent infection. persistence is characterized by rickettsemic cycles in which new a. marginale variant types, defined by the sequence of the expressed msp2 transcripts, emerge. the polymorphic msp2 transcripts encode structurally distinct msp2 proteins and result in an antigenically diverse and continually changing a. marginale population within the blood. in this manuscript, we used sequence analysis of msp2 ... | 1999 | 10077656 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 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 |
| 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 |
| dna binding properties of the ecdysteroid receptor in the salivary gland of the female ixodid tick, amblyomma hebraeum. | salivary gland degeneration in the female tick, amblyomma hebraeum koch (acari: ixodidae) is controlled by an ecdysteroid hormone. in an earlier study (mao, h., mcblain, w.a., kaufman, w.r., 1995. some properties of the ecdysteroid receptor in the salivary gland of the ixodid tick, amblyomma hebraeum. gen. comp. endocrinol. 99, 340-348), we demonstrated that a protein component of a salivary gland extract binds to ponasterone a (pon a) with high affinity (kd-1 nm), suggesting a tick ecdysteroid ... | 1998 | 9887511 |
| a possible explanation of the apparent breed-related resistance in cattle to bont tick (amblyomma hebraeum) infestations. | adult male amblyomma hebraeum tick infestations and the weights of 20 brahman steers and 38 mashona heifers were measured at different periods at the veterinary quarantine area at mbizi, zimbabwe. the experiment for the brahmans lasted 108 weeks and that for the mashona for 113 weeks. the brahman steers weighed a maximum average of 478.4 kg (se 7.9 kg), which was significantly different to the mashona heifers maximum average of 391.4 kg (se 5.6 kg) (p < 0.001). the brahmans had a maximum average ... | 1996 | 9017875 |
| catabolism of dopamine and 5-hydroxytryptamine by monoamine oxidase in the ixodid tick, amblyomma hebraeum. | the purpose of this study was to assess biogenic amine catabolism in amblyomma hebraeum koch (an african cattle tick). we assayed haemolymph and saliva for a variety of biogenic amines (usually following injection of substrate into the haemolymph) in partially fed females using hplc coupled to electrochemical detection. dopamine (da) and 5-hydroxytryptamine (5-ht) were rapidly converted to dihydroxyphenylacetic acid (dopac) and 5-hydroxyindoleacetic acid (5-hiaa) respectively, indicating that mo ... | 1996 | 8673075 |
| 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 |
| 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 |
| 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 |
| the life-cycle of the bont tick amblyomma hebraeum in vitro. | the life-cycle of the hard tick amblyomma hebraeum was completed in vitro by feeding all life-stages of the tick through silicone membranes on bovine blood from an abattoir. ticks were placed in a simple feeder membranes on bovine blood from an abattoir. ticks were placed in a simple feeder consisting of a honey jar containing the blood with a glass tube insert (o.d. 42 mm) across the end of which the membrane was stretched. this feeding unit was held in a water bath (38 degrees c). larvae and n ... | 1995 | 8550288 |
| 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 |
| 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 |
| evaluating the economic damage threshold for bont tick (amblyomma hebraeum) control in zimbabwe. | controlling ticks and tick-borne diseases by frequent applications of acaricides (e.g., dipping) is costly, and can leave treated livestock vulnerable to epizootics of tick-borne diseases should the system of applying acaricides break down. the concept of only applying acaricides on an infrequent (strategic) basis often relies on the target tick population displaying a seasonal cycle. however, as adult bont tick (amblyomma hebraeum) infestations in zimbabwe's lowveld do not have a strictly seaso ... | 1993 | 7628230 |
| 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 |
| 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 |
| cattle ticks from the waterberg district of the transvaal. | macroscopically visible ticks were collected from the hides of 28 cattle slaughtered in pairs during a period of 14 months in the waterberg district. in order of prevalence rhipicephalus appendiculatus, rhipicephalus evertsi evertsi, amblyomma hebraeum, hyalomma marginatum rufipes, ixodes cavipalpus, hyalomma truncatum and boophilus decoloratus were recovered. immature stages of the three commonest species constituted a major portion of the population for varying periods during the months april ... | 1980 | 7452655 |
| 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 |
| parasites of domestic and wild animals in south africa. xv. the seasonal prevalence of ectoparasites on impala and cattle in the northern transvaal. | the prevalence of ectoparasites on a total of 36 impala (aepyceros melampus) slaughtered monthly from february 1975 to february 1976 and a total of 24 cattle slaughtered monthly from march 1976 to march 1977 in the nylsvley provincial nature reserve was determined. six species of ixodid ticks were collected from the impala and these, in order of abundance, were: rhipicephalus evertsi evertsi, rhipicephalus appe. diculatus, amblyomma hebraeum, boophilus decoloratus, ixodes cavipalpus and hyalomma ... | 1982 | 7177586 |
| male engorgement factor: role in stimulating engorgement to repletion in the ixodid tick, dermacentor variabilis. | mating in ticks results in profound physiological changes that eventually results in egg production. in the american dog tick, dermacentor variabilis, mating causes partially blood-fed female ticks to commence rapid engorgement to repletion and eventual detachment from the host and egg laying. the peptidic male pheromone (engorgement factor alpha/beta) transferred to the female during mating is known only from a single tick species, amblyomma hebraeum, and was shown to consist of two peptides pr ... | 2009 | 19538967 |
| the detection of antibodies to cowdria ruminantium in serum and c. ruminantium antigen in amblyomma hebraeum by an enzyme-linked immunosorbent assay. | a sensitive and reliable enzyme-linked immunosorbent assay for the detection of antibodies to cowdria ruminantium in serum and c. ruminantium antigen in amblyomma hebraeum nymphae is described. for the screening of antibodies, c. ruminantium from a. hebraeum nymphae, partially purified by wheat-germ lectin affinity chromatography, was used as antigen. to screen nymph populations, sera from either ball 3 strain-infected sheep or kumm-strain infected mice were used. by using appropriate controls t ... | 1986 | 3960490 |
| rhipicephalus (boophilus) microplus: clotting time in tick-infested skin varies according to local inflammation and gene expression patterns in tick salivary glands. | ticks deposit saliva at the site of their attachment to a host in order to inhibit haemostasis, inflammation and innate and adaptive immune responses. the anti-haemostatic properties of tick saliva have been described by many studies, but few show that tick infestations or its anti-haemostatic components exert systemic effects in vivo. in the present study, we extended these observations and show that, compared with normal skin, bovine hosts that are genetically susceptible to tick infestations ... | 2010 | 20045690 |
| the comparative prevalence of five ixodid tick species infesting cattle and goats in maputo province, mozambique. | this study compares the prevalence of ixodid tick species on cattle and goats in maputo province. adult ticks as well as the nymphs of three species, and only the adults of two species were collected from sets of five cattle at 21 localities throughout the province and compared with those collected from similar sets of goats at the same places. amblyomma hebraeum adults and/or nymphs were present on cattle and on goats at all 21 localities, and 90 cattle and 22 goats were infested with adult tic ... | 2009 | 20698440 |
| efficacy of ivermectin against ectoparasites of cattle in south africa. | the efficacy of various formulations of ivermectin administered at the recommended dose rate of 200 micrograms/kg was evaluated in cattle infested with mange mites (sarcoptes scabiei var. bovis.), lice (linognathus vituli and damalinia bovis) and ticks (boophilus decoloratus, amblyomma hebraeum, rhipicephalus appendiculatus and hyalomma spp.) in 8 trials conducted in south africa. mange mites (s. scabiei) were eliminated from animals treated subcutaneously, resulting in marked clinical recovery. ... | 1985 | 3839021 |
| species composition and geographic distribution of ticks infesting cattle, goats and dogs in a temperate and in a subtropical region of south-east africa. | the species and distribution of ticks infesting cattle, goats and dogs in the eastern region of the eastern cape province, south africa and maputo province, mozambique were determined from collections made from these animals at 72 localities in the former region and 30 in the latter. eleven ixodid and one argasid species were recovered in the eastern cape province and 15 ixodid species in maputo province. the most common ticks infesting cattle and goats in both provinces were amblyomma hebraeum, ... | 2009 | 21105593 |
| chemical control of the heartwater vectors. | this paper reviews available literature on the efficacy of acaricides against amblyomma hebraeum and other tick species, and presents information on tests done with registered chemicals in the laboratory. little published information is available on the efficacy of chemicals specifically against a. hebraeum. a host of formulations are registered for use as acaricides on cattle, sheep, and goats in south africa and thus, by implication, against this species. resistance has only been described to ... | 1987 | 3329335 |
| rna interference in ticks. | ticks are obligate hematophagous ectoparasites of wild and domestic animals and humans, and are considered to be second worldwide to mosquitoes as vectors of human diseases(1) and the most important vectors affecting cattle industry worldwide(2). ticks are classified in the subclass acari, order parasitiformes, suborder ixodida and are distributed worldwide from arctic to tropical regions(3). despite efforts to control tick infestations, these ectoparasites remain a serious problem for human and ... | 2011 | 21304465 |
| ability of adults of amblyomma hebraeum (acarina: ixodidae) to feed repeatedly on sheep and cattle. | adult amblyomma hebraeum ticks were exposed at 14-day intervals on five sheep on 46 occasions and on three cattle on 15 occasions to determine the effects of repeated feeding. the engorged weight and percentage of ticks which fed successfully on sheep declined significantly at first but subsequently they increased. on cattle there was no progressive decline in engorged weight, although the percentage which fed successfully declined significantly and was lower than that for sheep. this decline wa ... | 1988 | 3201710 |
| First transcriptome of the testis-vas deferens-male accessory gland and proteome of the spermatophore from Dermacentor variabilis (Acari: Ixodidae). | Ticks are important vectors of numerous human diseases and animal diseases. Feeding stimulates spermatogenesis, mating and insemination of male factors that trigger female reproduction. The physiology of male reproduction and its regulation of female development are essentially a black box. Several transcriptomes have catalogued expression of tick genes in the salivary glands, synganglion and midgut but no comprehensive investigation has addressed male reproduction and mating. Consequently, a ne ... | 2011 | 21949745 |
| modulation of host immunity by tick saliva. | next generation sequencing and proteomics have helped to comprehensively characterize gene expression in tick salivary glands at both the transcriptome and the proteome level. functional data are, however, lacking. given that tick salivary secretions are critical to the success of the tick transmission lifecycle and, as a consequence, for host colonization by the pathogens they spread, we thoroughly review here the literature on the known interactions between tick saliva (or tick salivary gland ... | 2015 | 26189360 |
| vector potential and population dynamics for amblyomma inornatum. | we studied the natural life cycle of amblyomma inornatum and its vector potential in south texas. this tick is distributed throughout south texas and most of central america. a. inornatum represented 1.91% of the ticks collected by carbon dioxide traps during a study of free-living ticks in the tamaulipan biotic province in south texas. the life cycle of a. inornatum in south texas showed a clear seasonal pattern consistent with one generation per year. nymphs emerged in the spring with a peak i ... | 2015 | 25881916 |
| an annotated catalogue of salivary gland transcripts in the adult female mosquito, aedes aegypti. | saliva of blood-sucking arthropods contains a cocktail of antihemostatic agents and immunomodulators that help blood feeding. mosquitoes additionally feed on sugar meals and have specialized regions of their glands containing glycosidases and antimicrobials that might help control bacterial growth in the ingested meals. to expand our knowledge on the salivary cocktail of aedes aegypti, a vector of dengue and yellow fevers, we analyzed a set of 4,232 expressed sequence tags from cdna libraries of ... | 2007 | 17204158 |
| the effect of the bont tick (amblyomma hebraeum) on the weight gain of africander steers. | the effects of the bont tick amblyomma hebraeum on the productivity of cattle need to be quantified in order to design economically optimal control programs. liveweight gains (lwgs) of three groups of africander steers, maintained in the same pasture and exposed to zero, medium or high numbers of larvae, nymphs and adults of the tick, were measured. larvae and nymphs had no significant effect on lwg but adults had a large, statistically significant effect (p less than 0.05). the tick-free group ... | 1989 | 2815542 |
| the influence of interspecific competition and host preference on the phylogeography of two african ixodid tick species. | a comparative phylogeographic study on two economically important african tick species, amblyomma hebraeum and hyalomma rufipes was performed to test the influence of host specificity and host movement on dispersion. pairwise amova analyses of 277 mtdna coi sequences supported significant population differentiation among the majority of sampling sites. the geographic mitochondrial structure was not supported by nuclear its-2 sequencing, probably attributed to a recent divergence. the three-host ... | 2013 | 24130813 |
| new data regarding distribution of cattle ticks in the south-western indian ocean islands. | recent studies have produced new insight into the origin and distribution of some cattle ticks in the south-western indian ocean islands. rhipicephalus appendiculatus, introduced from tanzania in 2002, is now well established on grande comore but has not yet reached the other islands of the archipelago (mohéli, anjouan and mayotte). only one of the two clades identified in africa has settled so far. amblyomma variegatum, which was not supposed to be able to persist in the antananarivo region (13 ... | 2013 | 24016261 |
| simukunin from the salivary glands of the black fly simulium vittatum inhibits enzymes that regulate clotting and inflammatory responses. | black flies (diptera: simuliidae) feed on blood, and are important vectors of onchocerca volvulus, the etiolytic agent of river blindness. blood feeding depends on pharmacological properties of saliva, including anticoagulation, but the molecules responsible for this activity have not been well characterized. | 2012 | 22383955 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| seasonal occurrence of the bont tick (amblyomma hebraeum) in the southern lowveld of zimbabwe. | the seasonal occurrence of the bont tick amblyomma hebraeum was recorded over 2 years on 20 brahman cattle held in a 240-ha paddock at mbizi in southeastern zimbabwe. the cattle were infested with all life cycle stages throughout the study period, and no clearly defined seasonal patterns were recorded. males remained attached for up to about 6 months, and consequently accumulated on the cattle and outnumbered females considerably. the cattle did not acquire resistance to a. hebraeum and the abun ... | 1991 | 1786747 |
| the use of time-series analysis to forecast bont tick (amblyomma hebraeum) infestations in zimbabwe. | studying the dynamics of tick infestations on cattle is an essential step in developing optimal strategies for tick control. successful strategic tick control requires accurate predictions of when tick infestations will reach predetermined threshold levels. in the case of amblyomma hebraeum, earlier work has shown that there is no consistent pattern of seasonal activity. this means that a statistical model for predicting a. hebraeum infestations cannot reliably use climatic factors as the only i ... | 1992 | 1526202 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| diversity of ehrlichia ruminantium major antigenic protein 1-2 in field isolates and infected sheep. | proteins expressed from the map1 multigene family of ehrlichia ruminantium are strongly recognized by immune t and b cells from infected animals or from animals that were infected and have recovered from heartwater disease (although still remaining infected carriers). analogous multigene clusters also encode the immunodominant outer membrane proteins (omps) in other ehrlichial species. recombinant protein analogs of the expressed genes and dna vaccines based on the multigene clusters have been s ... | 2009 | 19307215 |