Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| acquisition of resistance to the tick amblyomma variegatum in boran cattle, bos indicus and the effects of trypanosoma congolense and babesia bigemina on host resistance. | resistance was induced in cattle to the tick amblyomma variegatum by five consecutive infestations with nymphs and adults. using the principal component analysis (pca), it was found that percentage of adults engorged, percentage of adults which died, percentage of nymphs which engorged, percentage of nymphs which moulted and percentage of nymphs which died, were the main indicators of resistance against a. variegatum. the percentages of nymphs which engorged or moulted after the third infestatio ... | 1996 | 8686177 |
| the association between amblyomma variegatum and dermatophilosis: epidemiology and immunology. | a close association was found between infestation with amblyomma variegatum and the occurrence of dermatophilosis on cattle on the coastal plains of ghana. animals belonging to breeds traditionally regarded as more susceptible to the disease also tended to carry higher tick burdens. the basis of the association between infestation with this tick and the occurrence of dermatophilosis would appear to involve tick-induced immunosuppression. | 1996 | 8809987 |
| amblyomma tick feeding in relation to host health. | the tick amblyomma variegatum has been shown by field and controlled laboratory experiments to have a direct causal relationship with severe clinical dermatophilosis. the tick does not transmit the pathogen in the usual sense, either biologically or mechanically. the tick suppresses the immune system of the host, for unknown reasons, and this appears to enable the existing dermatophilosis to become a severe disease. there are other factors involved with the progression of dermatophilosis to clin ... | 1996 | 8809988 |
| the pathogenesis of dermatophilosis. | pathogen, host and environmental factors must be considered in order to understand the pathogenesis of dermatophilosis. a frequently cited sequence of events involves physical damage to the skin, bacterial multiplication in the epidermis, repeated cycles of invasion by hyphae, infiltration by neutrophils and exudate, regeneration of epidermis and reinvasion. this paper is concerned with pathogen driven mechanisms involved in the origin and development of dermatophilus congolensis infections. pri ... | 1996 | 8809989 |
| heartwater in ghana: implications for control of ticks. | heartwater, an often fatal rickettsial disease of domestic ruminants transmitted by amblyomma variegatum ticks, ranks with the a. variegatum-associated skin disease dermatophilosis as a major constraint to the upgrading of livestock productivity in ghana. an epidemiological survey, using new diagnostic tests, is being carried out to determine the incidence and distribution of heartwater and other tickborne diseases in ghanaian cattle, sheep and goats. preliminary results from a longitudinal surv ... | 1996 | 8809994 |
| prospects for biological control of livestock ticks, rhipicephalus appendiculatus and amblyomma variegatum, using the entomogenous fungi beauveria bassiana and metarhizium anisopliae. | both beauveria bassiana and metarhizium anisopliae induced approximately 30% mortalities in adult rhipicephalus appendiculatus feeding on rabbits while m. anisopliae induced a mortality of 37% in adult amblyomma variegatum. both fungal species induced reductions in engorgement weights, fecundity, and egg hatchability in adult a. variegatum. m. anisopliae reduced fecundity by 94% in a. variegatum. furthermore, b. bassiana reduced egg hatchability to 0%, while 11% of the infected females failed to ... | 1996 | 8812559 |
| an assessment of host resistance to ticks on cross-bred cattle in burundi. | groups of cattle of four different cross-breeds (ankole x friesian, ankole x brown-swiss, ankole x guernsey, ankole x sahiwal) plus a group of pure ankole cattle were immunized against tick-borne diseases: east coast fever, using a theileria parva trivalent vaccine, and anaplasmosis, babesiosis and, subsequently, heartwater. with the exception of two small subgroups of ankole and ankole x sahiwal which were treated by weekly spraying using delnav, all the groups were exposed to natural field cha ... | 1996 | 8834737 |
| development of a computer model of the population dynamics of amblyomma variegatum and simulations of eradication strategies for use in the caribbean. | control or eradication efforts should cover wide areas because of long-range migration potential of immature ticks attached to birds, such as cattle egrets. careful follow-up inspections are also imperative. simulation 1 shows how rapidly the population numbers may expand from small numbers, either introduced or missed. simulation 4 indicates extending the treatment cycle beyond the residual effectiveness of the acaricide to save labor or funds would be false economy. the result could be to main ... | 1996 | 8784528 |
| tropical bont tick eradication campaign in the french antilles. current status. | the amblyomma variegatum eradication campaign was officially started in april 1994 in martinique and in guadeloupe, including its dependencies of marie galante, desirade and st martin. a budget of $10.5 and $5.9 million for guadeloupe and martinique, respectively, was initially (1991) calculated and considered necessary to achieve the program. however, eec, the most important donor, estimated that 75% only of this proposal was acceptable, on which it agrees to support a maximum of 50%. the balan ... | 1996 | 8784487 |
| potential impact of wildlife on the tropical bont tick eradication program in the caribbean. | wildlife are hosts for a. variegatum throughout its range in africa, and have been demonstrated to serve as hosts for larvae and nymphs on several islands in the caribbean. studies conducted in the caribbean have indicated that most larvae and nymphs and all adults of the tick feed on livestock; therefore, eradication can be approached through the treatment of livestock. however, since small numbers of animals such as the mongoose are infested with larvae and nymphs, these animals may represent ... | 1996 | 8784488 |
| factors of variation of amblyomma variegatum infestation on creole cattle in guadeloupe. | the level of infestation of "creole" beef cattle of guadeloupe by the tick amblyomma variegatum was recorded during a long-term survey in an experimental farm: 61 steers and 83 cows were distributed in different lots according to sex and management. they grazed continuously either on irrigated digitaria decumbens pastures or on dry native savannahs. tick numbers as well as animal weights were registered monthly. climatic data were also recorded. different acaricide treatments were tested during ... | 1996 | 8784527 |
| control of amblyomma variegatum and dermatophilosis on local and exotic breeds of cattle in ghana. | the occurrence of dermatophilosis on cattle in the tropics is closely associated with infestation by amblyomma variegatum ticks. animals that are more susceptible to the disease also tend to carry higher tick burdens. longitudinal studies carried out on the accra plains suggest that n'dama cattle acquire an enhanced degree of resistance to these ticks following initial exposure. lesions on zebu-type ghana sanga cattle tend to be confined to the predilection feeding sites of adult a. variegatum e ... | 1996 | 8809991 |
| contribution to the knowledge of ixodidae ticks of wild mammals of somalia. | this study was based on material collected in 1983-1984 from wild mammals of the middle scebeli. low scebeli and bay regions of somalia. a total of 292 specimens (156 males, 65 females, 70 nymphase, 1 larva) from 13 host species were examined. the following species of ixodidae were identified. amblyomma variegatum (fabricius, 1794); haemaphysalis calcarata neumann, 1902; haemaphysalis spinulosa neumann, 1906; rhipicephalus armatus pocock, 1900; rhipicephalus pravus donitz, 1910; rhipicephalus pu ... | 1996 | 9257347 |
| 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 |
| [insects know no border.]. | one of the major consequences of the joined action of demographic pressure and evolution of human activities lies in enormous increase of transportation, both in frequence and speed; taking advantage of these facilities, some arthropods could increase their geographical distribution and create new health threats. several demonstrative examples are exposed in order to illustrate this anthropic dissemination of the vectors : the introduction of anopheles gambiae s.l. in mauritius island between 18 ... | 1996 | 17292311 |
| crimean-congo hemorrhagic fever in ticks (acari: ixodidae) and ruminants: field observations of an epizootic in bandia, senegal (1989-1992). | from 1989 to 1992, a longitudinal study of the relationships between different tick species and domestic ungulates in the transmission and amplification of crimean-congo hemorrhagic fever (cchf) virus was undertaken in the bandia area in senegal where the presence of the virus had been reported previously. an epizootic occurred in 1991-1992 and 22 strains of cchf virus were isolated from hyalomma marginatum rufipes koch, amblyomma variegatum (f.), rhipicephalus guilhoni morel & vassiliades, and ... | 1997 | 9379454 |
| serological survey of heartwater relative to the distribution of the vector amblyomma variegatum and other tick species in north cameroon. | a study was carried out on the spatial and temporal distribution of amblyomma variegatum and other ticks infesting sheep and goats in northern cameroon. a serological survey of heartwater (cowdriosis) using a competitive elisa was concurrently carried out in the same flocks. a. variegatum was found to be the most predominant species accounting for 48.3% of all the ticks collected. other species identified included rhipicephalus sulcatus, r. lunulatus, r. turanicus, boophilus decoloratus, b. annu ... | 1997 | 9066062 |
| field sampling of the tick amblyomma variegatum (acari: ixodidae) on pastures in guadeloupe; attraction of co2 and/or tick pheromones and conditions of use. | field experiments were conducted in guadeloupe to evaluate the attraction of different chemicals on a guadeloupean strain of amblyomma variegatum. such tick sampling techniques may help to assess the size of the tick population on pastures before, during and after an attempted tick eradication campaign. co2 was absolutely necessary to activate ticks, including the larvae. in addition to activation, our data suggested that co2 itself is attractive for ticks. the reactivity of the ticks varied gre ... | 1997 | 9080680 |
| the impact of ixodiphagus hookeri, a tick parasitoid, on amblyomma variegatum (acari: ixodidae) in a field trial in kenya. | in an experiment to investigate the effect of the tick parasitoid, ixodiphagus hookeri, on tick numbers on cattle, 150000 parasitoids were released over a period of 1 year in a field where ten cattle infested with multiple tick species were kept. amblyomma variegatum was reduced from 44 to two ticks per animal while rhipicephalus appendiculatus increased over the time of parasitoid release. during the time of release 51% of the nymphs of a. variegatum collected from the animals were parasitized. ... | 1997 | 9080682 |
| on the mechanism of water vapour sorption from unsaturated atmospheres by ticks | the nascent salivary secretion of 41 partly dehydrated and unfed adult female amblyomma variegatum, 5­8 months post-ecdysis, during water vapour uptake at 93.5 % relative humidity and 20 °c, had an osmolality of between 298.6 and 769.7 mosmol kg-1 (mean ± s.d. 470.3±85.8 mosmol kg-1). this range would allow water vapour uptake at relative humidities of approximately 98­99 %, but it would not suffice for lower relative humidities down to 80­85 %, the critical equilib ... | 1997 | 9319391 |
| seasonal prevalence of ticks and tick-transmitted haemoparasites in traditionally managed n'dama cattle with reference to strategic tick control in the gambia. | a survey of tick spatial and seasonal distribution in traditional managed n'dama cattle over 1 year old was carried out in the gambia over 16 months. presence of anaplasma marginale and babesia spp. in the blood smears and their antibodies in the serum of same animals were also examined. tick species, in decreasing order of abundance, were: boophilus geigy, rhipicephalus senegalensis, b.decoloratus, hyalaomma truncatum, h.marginatum rufipes and amblyomma variegatum. all tick species peaked durin ... | 1997 | 9430113 |
| development, reproductive capacity and survival of amblyomma variegatum and boophilus decoloratus in relation to host resistance and climatic factors under field conditions. | to determine the developmental periods, fecundity and survival of amblyomma variegatum and boophilus decoloratus and the effect of host resistance, a study was carried out in the field at abernossa ranch in ethiopia using three breeds of cattle: arssi, boran and boran x friesian crossbreed. the investigation took place between october 1991 and september 1992. the developmental periods of both tick species were recorded. the hatching periods of larvae, engorgement, larvo-nymphal and nympho-adult ... | 1998 | 9637226 |
| in vitro susceptibilities of 27 rickettsiae to 13 antimicrobials. | the mics of 13 antibiotics (doxycycline, thiamphenicol, rifampin, amoxicillin, gentamicin, co-trimoxazole, ciprofloxacin, pefloxacin, ofloxacin, erythromycin, josamycin, clarithromycin, and pristinamycin) were determined for 27 available rickettsial species or strains. we used two in vitro cell culture methods described previously: the plaque assay and the microplaque colorimetric assay. our results confirm the susceptibilities of rickettsiae to doxycycline, thiamphenicol, and fluoroquinolones. ... | 1998 | 9660979 |
| the caricom/fao/iica caribbean amblyomma program. | the objective of the caribbean amblyomma program is to eradicate the tropical bont tick (tbt), amblyomma variegatum, from the caribbean. field activities directed to eradication of the tbt were initiated in may 1995 commencing in northern caribbean islands. plans have been finalized for the remaining islands to the south to start eradication activities in early 1997. the components of the program include tick control and surveillance, adaptive research, training, communications, and extension. d ... | 1998 | 9668484 |
| mx1-based resistance to thogoto virus in a2g mice is bypassed in tick-mediated virus delivery. | the interferon-induced mouse mx1 protein has intrinsic antiviral activity against orthomyxoviruses, including thogoto virus. thus, mx1(+) a2g mice are apparently resistant to infection following needle- or tick-borne virus challenge. however, tick-borne challenge and, to a lesser degree, injection of virus mixed with tick salivary gland extract resulted in virus transmission to uninfected ticks feeding on the a2g mice. the data indicate that immunomodulatory components in tick saliva can overcom ... | 1998 | 9733885 |
| ixodid tick infestations of wild birds and mammals on a game ranch in central province, zambia. | ticks were collected at irregular intervals from december 1995 to november 1996 from wildlife on mtendere game ranch in the chisamba district of central province, zambia. total collections were made from two species of ground-nesting birds and 20 species of small and large mammals. thirteen species/subspecies of ixodid ticks were recovered. rhipicephalus appendiculatus was the most abundant, followed by boophilus decoloratus and rhipicephalus evertsi evertsi. small numbers of immature ticks of o ... | 1998 | 9741055 |
| effect of controlling natural field-tick infestation on the growth of n'dama and gobra zebu cattle in the gambia. | the effect of tick infestations on liveweight gain (lwg) was assessed by comparison of weight changes in flumethrin-treated n'dama and gobra zebu cattle (16-20 months old) with respective control groups submitted to natural tick challenge over 1 year. flumethrin was applied monthly, fortnightly or weekly. preventive treatments against anaplasmosis, babesiosis and trypanosomosis were given. mortality rate was recorded and post-mortem examinations carried out. in both treated and control animals, ... | 1998 | 9604263 |
| efficacy of tags impregnated with pheromone and acaricide for control of amblyomma variegatum. | the efficacy of tags impregnated with pheromone and acaricide for control of amblyomma variegatum on cattle in guadeloupe was determined for a 13-week trial. comparisons were made between untreated cattle and cattle with tags containing either pheromones alone (o-nitrophenol, methyl salicylate, 2,6-dichlorophenol and phenylacetaldehyde), pheromones plus acaricide (cyfluthrin or deltamethrin), or acaricide alone. tags were fastened to cattle both on collars on the neck and with adhesive to tail h ... | 1998 | 9622367 |
| dynamics of free-living ixodid ticks on a game ranch in the central province, zambia. | free-living ixodid ticks were collected at monthly intervals from january to december 1996 by dragsampling the vegetation of mtendere game ranch in the chisamba district of the central province, zambia. ticks belonging to 11 species were recovered. rhipicephalus appendiculatus was most abundant, comprising 90% of the total number collected. all life stages of this tick showed a definite seasonal pattern of activity. the adults were present mainly during the rainy season (february and march), the ... | 1998 | 9629590 |
| african swine fever virus infection in the argasid host, ornithodoros porcinus porcinus. | the pathogenesis of african swine fever virus (asfv) infection in ornithodoros porcinus porcinus was examined in nymphal ticks infected with the asfv isolate chiredzi/83/1. at times postinfection (p.i.) ranging from 6 h to 290 days, ticks or dissected tick tissues were titrated for virus and examined ultrastructurally for evidence of virus replication. the asfv infection rate in ticks was 100% in these experiments, and virus infection was not associated with a significant increase in tick mortal ... | 1998 | 9499019 |
| taxonomic relationships among spotted fever group rickettsiae as revealed by antigenic analysis with monoclonal antibodies. | the spotted fever group (sfg) is made up of more than 20 different rickettsial species and strains. study of the taxonomic relationships among the group has been attempted by phenotypic, genotypic, and phylogenetic analyses. in this study, we determined taxonomic relationships among the sfg rickettsiae by comparative analysis of immunogenic epitopes reactive against a panel of monoclonal antibodies. a total of 98 monoclonal antibodies, which were directed against epitopes on the major immunodomi ... | 1998 | 9542904 |
| 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-ribotyping of xenorhabdus and photorhabdus isolates from the caribbean region in relation to the taxonomy and geographic distribution of their nematode hosts. | the genetic diversity of symbiotic xenorhabdus and photorhabdus bacteria associated with entomopathogenic nematodes was examined by a restriction fragment length polymorphism analysis of pcr-amplified 16s rrna genes (rdnas). a total of 117 strains were studied, most of which were isolated from the caribbean basin after an exhaustive soil sampling. the collection consisted of 77 isolates recovered from entomopathogenic nematodes in 14 caribbean islands and of 40 reference strains belonging to xen ... | 1998 | 9797272 |
| 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 |
| 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 |
| successes and failures in the tropical bont tick eradication campaigns in the french antilles. | the amblyomma variegatum eradication campaigns, based on three phases and a 5-year program, as in other islands of the caribbean, started in the french antilles in april 1994 with various financial inputs. the progress of the campaigns in the two islands of guadeloupe and martinique contrast sharply. owing to a shortage and inadequacy of results with regard to the initial objectives, particularly in organization, communication efforts, cattle identification, and application of acaricides on live ... | 1998 | 9668485 |
| a review of heartwater and the threat of introduction of cowdria ruminantium and amblyomma spp. ticks to the american mainland. | heartwater, caused by the rickettsial agent cowdria ruminantium, is one of the most devastating livestock diseases in sub-saharan africa. in addition to domestic cattle, sheep, and goats, a variety of nondomestic species can acquire subclinical and clinical infections. recent epidemiologic findings that demonstrate a long-term host carrier state in domestic and wild ruminants, intrastadial transmission by the tick vectors (amblyomma spp.), vertical transmission of the agent from cows to their ca ... | 1998 | 9732023 |
| phylogenetic placement of rickettsiae from the ticks amblyomma americanum and ixodes scapularis. | a rickettsial isolate (isolate moaa) belonging to the spotted fever group (sfg) was obtained from the lone star tick amblyomma americanum. we used pcr to characterize the genes for the rickettsial outer membrane proteins rompa and rompb. we sequenced the pcr products (domains i of both the rompa gene and the rompb gene) of moaa and wb-8-2, another rickettsial isolate from a. americanum. to place moaa and wb-8-2 and two other nonpathogenic isolates (rickettsia rickettsii hip2 and rickettsia monta ... | 1998 | 9574696 |
| attempts to feed amblyomma variegatum ticks on artificial membranes. | feeding jars were used to feed nymphs of amblyomma variegatum on blood of goats or cattle. sterile blood was collected daily or weekly (kept at 4 degrees c or frozen until use), with addition either of heparin alone or of heparin and antibiotics/fungicide or of heparin, adenosine triphosphate and glutathione. membranes were made of a thin (0.12-0.32 mm) film of silicone mastic. blood in the jars was replaced twice a day, and reached a temperature of 39 degrees c in a waterbath before it became a ... | 1998 | 9668493 |
| repeatability of the level of infestation by amblyomma variegatum ticks on creole cattle. | 1998 | 9668494 | |
| seasonal variation of ticks on cattle in burkina faso. | cattle of the sahel zebu peuhl breed from traditionally managed livestock herds in a representative area of north soudanese savana (with 400-900 mm of rainfall/year from may to september) located in the central land of burkina faso, were monitored over 12 months for tick and blood parasite. two species of ticks were found: amblyomma variegatum and hyalomma marginatum rufipes. h. m. rufipes was found on cattle all year round with a highest infestation rate in june characterized by means of 10 +/- ... | 1998 | 9668496 |
| simultaneous detection of bovine theileria and babesia species by reverse line blot hybridization. | a reverse line blot (rlb) assay was developed for the identification of cattle carrying different species of theileria and babesia simultaneously. we included theileria annulata, t. parva, t. mutans, t. taurotragi, and t. velifera in the assay, as well as parasites belonging to the t. sergenti-t. buffeli-t. orientalis group. the babesia species included were babesia bovis, b. bigemina, and b. divergens. the assay employs one set of primers for specific amplification of the rrna gene v4 hypervari ... | 1999 | 10325324 |
| [experimental transmission of crimean-congo hemorrhagic fever virus: role of 3 vector species in the maintenance and transmission cycles in senegal]. | in this article, we published the role of three species of ticks amblyomma variegatum (fabricius, 1974), hyalomma marginatum rufipes (koch, 1844) and hyalomma truncatum (koch, 1844) in the maintenance and transmission of the cchf virus. the imagos of these species were infected by intracoelomic route. vertical transmission (transtasial and transovarial) and horizontal transmission for different stases were studied by isolation on newborn mice, polymerase chain reaction, indirect immunofluorescen ... | 1999 | 10229934 |
| population dynamics of ticks on indigenous cattle in a pastoral dry to semi-arid rangeland zone of uganda. | studies on seasonality and population dynamics of ticks on indigenous cattle and their crosses (calves) were carried out in buruli ranching scheme, nabiswera, luwero district of uganda on three treatment groups of animals: group 1 (twice a week dipping), group 2 (once a month dipping) and group 3 (no tick control). during this study, four major species of ticks of economic importance were recorded in decreasing order of abundance: rhipicephalus appendiculatus, rhipicephalus evertsi evertsi, ambl ... | 1999 | 10353189 |
| immune responses to dermatophilus congolensis infections. | complex mechanisms underly the establishment of dermatophilosis, an exudative and proliferative skin disease of ruminants. this multicomponent system involves the bacterium dermatophilus congolensis, transmission by various routes including flies, host genetic factors and immunosuppression by amblyomma variegatum ticks. here, nick ambrose and colleagues summarize recent evidence for an association between a. variegatum and severe chronic dermatophilosis in cattle. breed-based differences in resi ... | 1999 | 10377534 |
| tick-borne rickettiosis in guadeloupe, the french west indies: isolation of rickettsia africae from amblyomma variegatum ticks and serosurvey in humans, cattle, and goats. | twenty-seven rickettsiae were isolated and/or detected from 100 amblyomma variegatum ticks collected on guadeloupe in the french west indies. in this study, the polymerase chain reaction procedure appeared to be more sensitive in detecting rickettsiae in ticks than the shell-vial technique. sequencing a portion of the outer membrane protein a-encoding gene showed that these rickettsiae appeared to be identical to rickettsia africae, a member of the spotted fever group rickettsiae recently descri ... | 1999 | 10403315 |
| toxicity of neem seed oil (azadiracta indica) against the larvae of amblyomma variegatum a three-host tick in cattle. | the in vitro toxicity of neem seed oil (azadiracta indica, family: meliaceae, 'dogon yaro' in hausa -language) was tested against the larvae of a three-host tick, amblyomma variegatum (family: ixodidae or hard tick) parasitic to cattle commonly found in nigeria. undiluted neem oil (100% concentration) was found to kill all (100% mortality) the larvae after 48 h. the toxicity was concentration and time dependent. | 1999 | 10479769 |
| african swine fever virus replication in the midgut epithelium is required for infection of ornithodoros ticks. | although the malawi lil20/1 (mal) strain of african swine fever virus (asfv) was isolated from ornithodoros sp. ticks, our attempts to experimentally infect ticks by feeding them this strain failed. ten different collections of ornithodorus porcinus porcinus ticks and one collection of o. porcinus domesticus ticks were orally exposed to a high titer of mal. at 3 weeks postinoculation (p.i.), <25% of the ticks contained detectable virus, with viral titers of <4 log(10) 50% hemadsorbing doses/ml. ... | 1999 | 10482612 |
| molecular individuality: polymorphism of salivary gland proteins in three species of ixodid tick. | pooled tissue samples are frequently used in biochemical studies involving parasites in order to ensure that there is sufficient material for experimentation. a pooled sample is considered to represent the overall phenotypic characteristics of the investigated population. however, this will not be the case if there is a significant degree of molecular polymorphism among individuals in the sampled population. here we demonstrate marked differences in the protein profile of salivary glands among i ... | 1999 | 10737731 |
| feasibility of controlling ixodes scapularis ticks (acari: ixodidae), the vector of lyme disease, by parasitoid augmentation. | a theoretical analysis of the feasibility of controlling tick populations (ixodidae) by the release of reared ixodiphagus parasitoids in tick ecosystems yielded promising results. the analysis suggested that if reasonable progress could be made in mass-rearing the parasitoids, it would be possible to control the blacklegged tick, ixodes scapularis (say), the vector of lyme disease, by this biological control procedure. lyme disease has become the most important vector-borne disease in the united ... | 2000 | 11004774 |
| 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 |
| 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 |
| 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 |
| 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 |
| ticks and tick-borne disease systems in space and from space. | analyses within geographical information systems (giss) indicate that small- and large-scale ranges of hard tick species (ixodidae) are determined more by climate and vegetation than by host-related factors. spatial distributions of ticks may therefore be analysed by statistical methods that seek correlations between known tick presence/absence and ground- or remotely-sensed (rs) environmental factors. in this way, local habitats of amblyomma variegatum in the caribbean and ixodes ricinus in eur ... | 2000 | 10997208 |
| earth observation, geographic information systems and plasmodium falciparum malaria in sub-saharan africa. | this review highlights the progress and current status of remote sensing (rs) and geographical information systems (gis) as currently applied to the problem of plasmodium falciparum malaria in sub-saharan africa (ssa). the burden of p. falciparum malaria in ssa is first summarized and then contrasted with the paucity of accurate and recent information on the nature and extent of the disease. this provides perspective on both the global importance of the pathogen and the potential for contributio ... | 2000 | 10997207 |
| invasion of west african cattle by the tick amblyomma variegatum. | studies in cameroon and burkina faso examined the invasion process of cattle by adult amblyomma variegatum fabricius (acari: ixodidae) ticks. nearly all the ticks picked up in the pasture during grazing were found on the limb ends, near the hooves, where they temporarily attached. then when the cattle lay down, the ticks moved from the feet towards the predilection sites, where they attached definitively. many ticks disappeared during this displacement. all the female ticks and approximately 70% ... | 2000 | 11129703 |
| laboratory and field evaluation of entomogenous fungi for tick control. | aqueous and oil-based formulations of two entomogenous fungi, beauveria bassiana and metarhizium anisopliae were tested for their efficacy against the three major species of african ticks; namely, amblyomma variegatum, rhipicephalus apendiculatus, and boophilus decoloratus. both fungal species and formulations were observed to induce high mortalities, especially in the larvae. the oil-based formulation was found to be more effective than the aqueous formulation. monthly application of aqueous fo ... | 2000 | 11193673 |
| 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 |
| new and earlier records of ticks (acari: ixodidae, argasidae) from guinea-bissau. | ticks were collected from pastures and domestic and wild vertebrates during the rainy seasons of 1994 and 1996 in guinea-bissau. we collected the following species: from pastures rhipicephalus lunulatus neumann, r. muhsamae morel & vassiliades, r. senegalensis koch, and r. sulcatus neumann; from reptiles amblyomma nuttalli dönitz and aponomma flavomaculatum (lucas); and from mammals amblyomma paulopunctatum neumann, amblyomma splendidum giebel, amblyomma variegatum (f.), hyalomma truncatum koch, ... | 2000 | 11126561 |
| 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 |
| laboratory evaluation of pathogenicity of entomogenous nematodes to african tick species. | five strains of entomogenous nematodes, steinernema carpocapsae strains dd, mexican, sr, and heterorhabditis bacteriophora strains 1s5 and hp88, were tested for their pathogenicity to various developmental stages of five african tick species namely; rhipicephalus appendiculatus, r. evertsi, amblyomma variegatum, a. gemma, and boophilus decoloratus. in engorged female r. appendiculatus, all nematodes at a concentration of 1,000 infective juveniles (ij)/dish, except s. carpocapsae mexican strain, ... | 2000 | 11193637 |
| 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 |
| cowdria ruminantium antibodies in acaricide-treated and untreated cattle exposed to amblyomma variegatum ticks in the gambia. | an indirect enzyme-linked immunosorbent assay (elisa), based on the major antigenic protein i fragment b (mapi-b) of cowdria ruminantium, was used to assess seroprevalence in cattle in the gambia. two groups of 20 n'dama and 20 gobra zebu cattle were monitored for 12 months with flumethrin treatment and for another 10 months without acaricidal treatment. two groups of 20 n'dama and 20 gobra cattle served as untreated controls. during the period of acaricidal treatment, the cumulative proportions ... | 2000 | 11354623 |
| 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 |
| entomogenous fungi as promising biopesticides for tick control. | when ticks were sealed in nylon tetrapacks and infected with the entomogenous fungi, beauveria bassiana and metarizium anisopliae and maintained in potted grass in the field, the fungal oil formulations (10(9) conidia per ml) induced 100% mortality in larvae of rhipicephalus appendiculatus and amblyomma variegatum, whereas mortalities in nymphs varied between 80-100% and in adults 80-90%. the aqueous formulations (10(9) conidia per ml) induced mortalities of 40-50% and reductions in egg hatchabi ... | 2000 | 11354619 |
| dermatophilus congolensis infection in goats in tanzania. | when goats in eastern tanzania were screened for skin diseases, dermatophilus congolensis was isolated from the skin lesions in 8 of 484 animals examined. in one severely affected case, the disease was also characterized by histological studies (gram stain, giemsa stain and routine he studies) and electron microscopy. the histological picture was characterized by hyperkeratosis, parakeratosis, acanthosis, folliculitis and an inflammatory cellular reaction involving the epidermis. gram stain and ... | 2001 | 11556616 |
| the distribution of ixodid ticks (acari: ixodidae) in central ethiopia. | ixodid ticks were collected from domestic animals, mainly cattle, in 11 administrative zones covering 84 districts in central ethiopia over a period of 2 years (july 1996 to june 1998). nineteen tick species were identified. four of these belonged to the genus amblyomma, one to boophilus, two to haemaphysalis, three to hyalomma and nine to rhipicephalus. amblyomma variegatum and rhipicephalus evertsi evertsi were present in all 11 administrative zones and, with the exception of afar, boophilus d ... | 2001 | 12026058 |
| 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 |
| tick infestation of borana cattle in the borana province of ethiopia. | a study was conducted to identify and determine burdens of ticks infesting borana cattle in the borana province of ethiopia. rhipicephalus pulchellus, rhipicephalus pravus, rhipicephalus muhsamae, rhipicephalus praetextatus, rhipicephalus evertsi evertsi, amblyomma gemma, amblyomma variegatum, amblyomma cohaerens, amblyomma lepidum, hyalomma truncatum, hyalomma marginatum rufipes and boophilus decoloratus were identified on the cattle. their burdens ranged from 658-1,554 with a mean of 1,205 tic ... | 2001 | 11403429 |
| 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 |
| evidence for the utility of the bm86 antigen from boophilus microplus in vaccination against other tick species. | the bm86 antigen, as originally identified in boophilus microplus, is the basis of commercial tick vaccines against this tick species. the potential for using this antigen or homologues of the antigen in vaccination against other tick species has been assessed. we have conducted vaccine trials in cattle using the b. microplus-derived recombinant bm86 vaccine (tickgard) using pairs of vaccinated calves and control calves. these were infested with b. microplus and boophilus decoloratus larvae simu ... | 2001 | 11523920 |
| anti-interleukin-8 activity of tick salivary gland extracts. | interleukin-8 (il-8) is one of many mammalian chemokines (chemotactic cytokines) that direct mammalian inflammatory and immune cells to sites of injury and infection. chemokines are produced locally and act on leucocytes through selective receptors. the principal role of il-8 is to control the movement and activity of neutrophils. to date, several tick species have been shown to modulate the production or activity of certain cytokines but none of these are chemokines. using an il-8 specific elis ... | 2001 | 11589777 |
| 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 |
| seasonal epidemiology of ticks and aspects of cowdriosis in n'dama village cattle in the central guinea savannah of côte d'ivoire. | in the central guinea savannah of côte d'ivoire, cattle breeding started only approximately 30 years ago. the impact of parasitism on the overall health status and productivity of the trypanotolerant n'dama cattle in this area is unknown. in close collaboration with national veterinary institutions and local farmers, we studied spectrum, burden and seasonal dynamics of ticks (including aspects of cowdriosis) on n'dama village cattle. in a longitudinal study, three randomly selected cattle herds ... | 2002 | 11821134 |
| avgi, an index of genes transcribed in the salivary glands of the ixodid tick amblyomma variegatum. | random clones from a cdna library made from mrna purified from dissected salivary glands of feeding female amblyomma variegatum ticks were subjected to single pass sequence analysis. a total of 3992 sequences with an average read length of 580 nucleotides have been used to construct a gene index called avgi that consists of 2109 non-redundant sequences. a provisional gene identity has been assigned to 39% of the database entries by sequence similarity searches against a non-redundant amino acid ... | 2002 | 12392910 |
| transcriptional analysis of the major antigenic protein 1 multigene family of cowdria ruminantium. | the major antigenic protein 1 (map1) of the tick-borne rickettsial pathogen cowdria ruminantium is encoded by a multigene family containing conserved and variable genes. the part of a locus containing the map1 multigene family that was characterized contained three homologous, but non-identical map1 genes, designated map1-2, map1-1, and map1. reverse transcriptase-polymerase chain reaction was used to study the transcriptional activity of these genes in isolates of c. ruminantium grown in bovine ... | 2002 | 12039046 |
| 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 |
| heterogeneity in the effect of different ixodid tick species on human natural killer cell activity. | tick saliva plays a vital role in blood-feeding, including manipulation of the host response to tick infestation. furthermore, a diverse number of tick-borne pathogens are transmitted to vertebrate hosts via tick saliva, some of which exploit the immunomodulatory activities of their vector's saliva. we report that salivary gland extracts (sge) derived from dermacentor reticulatus adult ticks induce a decrease in the natural killer (nk) activity of effector cells obtained from healthy human blood ... | 2002 | 11856443 |
| increasing risks of introduction of heartwater onto the american mainland associated with animal movements. | opportunities to introduce heartwater onto the american mainland through animal movements include importation from africa of tick-infested reptiles and of subclinically infected wild ungulates and importation of livestock from islands in the caribbean infested with amblyomma variegatum ticks. measures to control importation of heartwater vectors on reptiles include importation bans of infested species, treatment of imported reptiles, and eradication of established infestations on the american ma ... | 2002 | 12381604 |
| 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 |
| simultaneous detection of anaplasma and ehrlichia species in ruminants and detection of ehrlichia ruminantium in amblyomma variegatum ticks by reverse line blot hybridization. | the detection of anaplasma and ehrlichia species is usually based on species-specific pcr assays, since no assay is yet available which can detect and identify these species simultaneously. to this end, we developed a reverse line blot (rlb) assay for simultaneous detection and identification of anaplasma and ehrlichia species in domestic ruminants and ticks. in a pcr the hypervariable v1 region of the 16s ribosomal rna (rrna) gene was amplified with a set of primers unique for members of the ge ... | 2002 | 12243899 |
| 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 |
| characterization of protective antigens from the midgut of amblyomma variegatum ticks. | separation of midgut membrane proteins from the tick, ambylomma variegatum, using a nonionic detergent (triton x-114), resulted in two protein fractions, namely det (detergent) and aq (aqueous). in immunoblotting analysis with polyclonal antibodies against these fractions, 4 proteins (mr approximately 27,000, 67,000, 86,000 and 95,000,) and 2 proteins (m, approximately 54,000 and 67,000) were detected in the det and aq fractions, respectively. three of the det fraction proteins mr approximately ... | 2002 | 12475080 |
| immunogenicity of ehrlichia ruminantium grown in tick cell lines. | ehrlichia (previously cowdria) ruminantium, the pathogen which causes heart-water in domestic and wild ruminants, can now be propagated in cell lines from one vector (amblyomma variegatum) and five non-vector (ixodes scapularis, i. ricinus, boophilus decoloratus, b. microplus and rhipicephalus appendiculatus) tick species. e. ruminantium isolates from west and south africa and the caribbean vary in their cell line preference, growth patterns and immunogenic capability. in laboratory trials, cert ... | 2002 | 14570129 |
| 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 |
| in vitro assays for repellents and deterrents for ticks: differing effects of products when tested with attractant or arrestment stimuli. | most in vivo and in vitro tests with repellents or deterrents against ticks have not considered which sensory channel is being targeted. we have recorded the responses of two hard tick species (acari: ixodidae) in vitro to determine if such products can disrupt the perception of an attractant in a repellent assay or the perception of an arrestment stimulus in a deterrent assay. ethyl butylacetylaminopropionate (ebaap), n,n-diethyl-methyl-benzamide (deet), permethrin and indalone were chosen to t ... | 2003 | 14651650 |
| modulation of human lymphocyte proliferation by salivary gland extracts of ixodid ticks (acari: ixodidae): effect of feeding stage and sex. | ixodid ticks remain attached to their hosts for several days to weeks. during this extended feeding process new proteins involved in the modulation of host immune responses are expressed in tick salivary glands. in our study a stimulatory or inhibitory effect of salivary gland extracts (sge) of unfed and partially fed female ixodes ricinus (linnaeus, 1758), female and male amblyomma variegatum (fabricius, 1794) and rhipicephalus appendiculatus neumann, 1901 ticks on human lymphocyte proliferatio ... | 2003 | 14971600 |
| a survey for spotted fever group rickettsiae and ehrlichiae in amblyomma variegatum from st. kitts and nevis. | eighty-nine amblyomma variegatum ticks were collected from the islands of st. kitts and nevis in the caribbean and preserved in 70% ethanol or local rum. after being washed in sterile water, their dna was extracted and analyzed by a polymerase chain reaction (pcr) for dna of spotted fever group rickettsiae and ehrlichiae. none of the tested ticks was positive in a pcr assay using the primers 16s ehrd and 16s ehrr for the 16s rrna gene of ehrlichia spp.. forty-one percent of the a. variegatum (36 ... | 2003 | 12932098 |
| 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 |
| detection by two enzyme-linked immunosorbent assays of antibodies to ehrlichia ruminantium in field sera collected from sheep and cattle in ghana. | two serological tests for detection of antibodies to ehrlichia (previously cowdria) ruminantium, the causative agent of heartwater, were compared by using field sera collected from sheep and cattle as part of serosurveys in ghana. sera selected as either negative or positive by a new polyclonal competitive enzyme-linked immunosorbent assay (pc-elisa) were tested by the indirect map1-b elisa. cutoff values of 14 percent positivity (14 pp) for both ruminant species were obtained for the map1-b eli ... | 2003 | 12965927 |
| selection assisted by a bola-dr/dq haplotype against susceptibility to bovine dermatophilosis. | bovine dermatophilosis is a severe skin infection of tropical ruminants inducing a severe loss in productivity and a 15% mortality rate. this disease is caused by the actinomycete bacterium dermatophilus congolensis associated with the tick amblyomma variegatum. currently there are no prospects for a vaccine, and acaricide or antibiotic control is hampered by the development of chemoresistance. animal breeders have observed that dermatophilosis susceptibility seems to be determined genetically, ... | 2003 | 12927091 |
| effect of fast protein liquid chromatography fractionated salivary gland extracts from different ixodid tick species on interleukin-8 binding to its cell receptors. | interleukin-8 plays a critical role in inflammatory processes. hence generation of molecules with anti-il-8 activity is likely to be important for successful feeding and for survival of the ticks. anti-il-8 activity was studied in saliva of three ixodid tick species--dermacentor reticulatus (fabricius, 1794), rhipicephalus appendiculatus neumann, 1901, and amblyomma variegatum (fabricius, 1794). the greatest activity was shown in saliva prepared from d. reticulatus. the activity was attributed t ... | 2003 | 12735728 |
| babesia bicornis sp. nov. and theileria bicornis sp. nov.: tick-borne parasites associated with mortality in the black rhinoceros (diceros bicornis). | a novel babesia species, designated babesia bicornis sp. nov., was identified in three black rhinoceroses (diceros bicornis) that died in wildlife areas in tanzania and south africa. screening of black rhinoceroses in south africa revealed, in addition to b. bicornis, a second parasite, designated theileria bicornis sp. nov. | 2003 | 12734294 |
| spotted fever group rickettsiae in ticks from the masai mara region of kenya. | we have identified for the first time rickettsia africae, and the ticks that harbored them, in kenya. a total of 5,325 ticks were collected from vegetation, livestock, and wild animals during two field trips to southwestern kenya. most were immature forms (85.2%) belonging to the genera amblyomma or rhipicephalus. the adults also included representatives from the genus boophilus. ticks were assessed for rickettsial dna by a polymerase chain reaction (pcr) using primers for the spotted fever grou ... | 2003 | 12812343 |
| widespread presence of "bacterial-like" ppp phosphatases in eukaryotes. | in eukaryotes, ppp (protein phosphatase p) family is one of the two known protein phosphatase families specific for ser and thr. the role of ppp phosphatases in multiple signaling pathways in eukaryotic cell has been extensively studied. unlike eukaryotic ppp phosphatases, bacterial members of the family have broad substrate specificity or may even be tyr-specific. moreover, one group of bacterial ppps are diadenosine tetraphosphatases, indicating that bacterial ppp phosphatases may not necessar ... | 2004 | 15555063 |
| some observations on the sero-prevalence of heartwater and tick infestation in zambian goats. | a survey was carried out to define the distribution of heartwater in goats that originated from six districts in communal grazing semi-arid areas of zambia. a total of 181 samples (40.1%) out of 451 serum samples from adult goats were positive for ehrlichia ruminantium antibodies after screening using indirect map-1b antigen elisa technique with statistically significant differences (p < 0.01) between the six districts. out of 1 036 adult goats examined for tick infestation, 105 were infested by ... | 2004 | 15373339 |
| susceptibility of mosquito and tick cell lines to infection with various flaviviruses. | the genus flavivirus consists of more than 70 virus species and subtypes, the majority of which are transmitted by mosquitoes or ticks, although some have no known vector (nkv). the ability of these viruses to infect cultured cells derived from mosquito or tick species offers a useful insight into the suitability of such vectors to harbour and replicate particular viruses. we undertook a comparative study of the susceptibility of mammalian vero cells, a clonal mosquito cell line (c6/36) and rece ... | 2004 | 15347394 |