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electron-microscopic studies on theileria ovis rodhain, 1916: development of kinetics in the gut of the vector tick, rhipicephalus evertsi evertsi neumann, 1897, and their transformation within cells of the salivary glands.gamogony of theileria ovis rodhain occurs within the gut of nymphs of the tick rhipicephalus evertsi evertsi neumann. after molting, spherical and ovoid parasites are found within the intestinal cells of the ticks. these stages are thought to be zygotes, because they undergo a transformation process leading ultimately (in 3 days) to the formation of a motile stage, the kinete, the fine structure of which is very similar to that of the ookinetes of the hemosporidia. the kinete leaves the gut cell ...1979119849
ticks from the african buffalo (syncerus caffer) in ngamiland, botswana.in november 1972, 93 out of 100 african buffalo from 3 areas in ngamiland, botswana, were found to be infested with ticks. the tick species present and the percentage of buffalo infested by each were: hyalomma truncatum (63%), h. rufipes (54%), rhipicephalus evertsi evertsi (68%), r. tricuspis (11%), r. simus (4%) and boophilus decoloratus (1%). the mean number of ticks per animal was 8,6 (standard deviation +/-4,1), representing a mean of 6,5+/-3,4 male and 2,1+/-1,9 female ticks. the incidence ...1976940665
viraemic transmission of crimean-congo haemorrhagic fever virus to ticks.in order to determine the way in which vertebrates infected with crimean-congo haemorrhagic fever (cchf) virus and potential ixodid tick vectors interact in nature, immature and adult ticks of several species were fed on viraemic mammals and then assayed for virus content at varying times after feeding. cchf virus was not isolated from ticks of six species tested after feeding as adults and immature forms on sheep with viraemia of 10(2.5-3.2) ld 50/ml, nor from larval ticks fed on guinea-pigs an ...19911902186
tick (acari: ixodidae) infestations on zebu cattle in western kenya: seasonal dynamics of four species of ticks on traditionally managed cattle.a study was conducted on the population dynamics of four tick species infesting livestock on rusinga island. infestations of rhipicephalus appendiculatus neumann, rhipicephalus evertsi evertsi neumann, amblyomma variegatum (f.)., and boophilus decoloratus (koch) were monitored on east african shorthorn zebu cattle at monthly intervals for 2 yr. these cattle were of unimproved stock under traditional husbandry without any tick control practices. most ticks were on cattle between september and mar ...19911941930
seasonal abundance of ticks associated with indigenous goats on a northern transvaal farm.the 3 most abundant tick species on indigenous goats on a northern transvaal farm were found to be rhipicephalus evertsi evertsi, rhipicephalus appendiculatus and amblyomma hebraeum. three other tick species were present in small numbers. the economical and ecological importance of the ticks found on the goats, mainly in rural areas where chemical control of ticks is practically non-existant, is discussed. the high number of goats in the study area and the shift towards alternative methods of ti ...19912051439
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 ...19902267728
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 ...19902339000
the interaction between the immune response of rabbits to heterologous antigens and a primary infestation with rhipicephalus evertsi evertsi.rhipicephalus evertsi evertsi feeding on hosts inoculated with sheep red blood cells (srbc) and bovine serum albumin (bsa) suppressed the primary antibody response to the two antigens. in addition, while the ticks paralysed most hosts in the studies, fatality associated with this toxicosis occurred only in rabbits which had received srbc, either alone or with bsa. only those hosts inoculated with bsa developed any resistance against the ticks, manifested by a slight reduction of engorged weights ...19902345952
expression of acquired immunity to immature stages of the tick rhipicephalus evertsi evertsi by rabbits and guinea-pigs.acquired immunity in guinea-pigs and rabbits to immature stages of the two-host tick rhipicephalus evertsi evertsi neumann was demonstrated. repeated infestations of both hosts with larvae resulted in a significant reduction in the weight of later engorged nymphs. a sharp decline in the numbers of nymphs which successfully fed on both hosts was also observed. this study provides evidence for a gradual decrease in the mean weight of engorged nymphs towards the end of the detachment period suggest ...19892519645
resistance and cross-resistance in guinea-pigs and rabbits to immature stages of ixodid ticks.infestation of guinea-pigs and rabbits with larvae of any one of five species of ticks, rhipicephalus appendiculatus neumann, rhipicephalus evertsi evertsi neumann, amblyomma hebrauem koch, amblyomma variegatum fabricius and ixodes ricinus l., conferred resistance in the animals when exposed to subsequent infestations with the same tick species. resistance to infestations by other tick species was not observed.19892519683
[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 ...19892607535
resistance to rhipicephalus evertsi evertsi in immunosuppressed rabbits.rabbits treated with goat anti-rabbit thymocyte serum acquired less resistance to rhipicephalus evertsi evertsi infestation than untreated controls. this inferior resistance was manifested as higher engorged weights of ticks and higher biotic potential, undue persistence of the ticks on the hosts and poor anti-tick antibody and delayed-type hypersensitivity responses. these observations highlight the significance of host t-cells in mediating resistance to ticks.19892672558
changes in the concentration of globulins in naive guinea pigs during feeding by the immature stages of rhipicephalus evertsi evertsi (acari: ixodidae).the weight of rhipicephalus evertsi evertsi neumann nymphs, which as larvae and nymphs completed the entire blood meal on the same individual guinea pig, was significantly lower than the weight of those that as larvae and nymphs fed on two separate naive hosts. nymphs of the latter category spent 1 wk (from unfed larvae to unfed nymphs) on one animal before their transfer to the second host to complete the blood meal. the albumin concentration of the host blood decreased and was related to the t ...19892769702
on the critical transition temperature of unfed adult rhipicephalus evertsi evertsi and rhipicephalus eversti mimeticus (ixodoidea: ixodidae). 19883218395
arthropod parasites of common reedbuck, redunca arundinum, in natal.twenty-five common reedbuck, redunca arundinum, from the himeville region, 21 from the eastern shores nature reserve, 4 from the charter's creek nature reserve and 2 from the st lucia game park, natal were examined for arthropod parasites. the reedbuck from himeville were infested with 4 ixodid tick species, those from the eastern shores with 7 species and those from charter's creek and st lucia with 6 species. rhipicephalus evertsi evertsi was the only tick common to the 4 localities. the lice ...19883353095
the transstadial transmission of babesia caballi by rhipicephalus evertsi evertsi.rhipicephalus evertsi evertsi larvae were fed on the ears of rabbits. seven days after larval infestation, unfed, newly moulted nymphae were manually removed to infest a splenectomized donkey showing a patent babesia caballi infection. engorged nymphae were collected from the donkey and the ensuing adult ticks were placed on a susceptible horse. the horse contracted a b. caballi infection showing a prepatent period of 19 days after tick infestation. a very low parasitaemia, (highest score 2), wh ...19873444624
histology and ultrastructure of the glands associated with the porose areas on the gnathosoma of rhipicephalus evertsi evertsi before and during oviposition.histological and electronmicroscopical studies have shown that the subcuticular tissue associated with the porose areas of female rhipicephalus evertsi evertsi consists of paired multicellular, alveolar and lobularly arranged glands. at least two types of cells are clearly distinguishable, according with their location. proximally, in direct association with the pores, cells with small and long nuclei are present. these cells are aligned along large, elongated lumina containing numerous microvil ...19873453789
[functional significance of the areae porosae of female rhipicephalus evertsi evertsi, neumann, 1897]. 19863536406
detection of immune response in rabbits infested with rhipicephalus appendiculatus and rhipicephalus evertsi evertsi.two groups of rabbits infested repeatedly with rhipicephalus evertsi evertsi and r appendiculatus acquired resistance as evidenced by reduced ectoparasite engorged weights and development of anti-tick antibodies in the hosts. the enzyme-linked immunosorbent assay (elisa) using salivary gland antigens of r appendiculatus was able to detect antibody responses to both the homologous and heterologous tick challenges. it was concluded that the immune response in hosts infested by these two tick speci ...19873685635
changes in the protein pattern in the salivary glands of paralysis inducing female rhipicephalus evertsi evertsi during infestation. 19863751387
investigations into the localization of pheromone emission of male rhipicephalus evertsi evertsi during infestation. 19863751390
investigations into the function and chemical compositions of the porose areas secretion of rhipicephalus evertsi evertsi during oviposition.major differences were observed in hexane, ethanol and butanol extracts of eggs obtained from rhipicephalus evertsi evertsi females in which the porose areas functioned normally (ap+ eggs) and from r. evertsi evertsi in which the porose areas were selectively destroyed by electrocautery (ap- eggs). mass yields and uv spectra of the hexane extracts were similar for ap+ and ap- eggs. the uv spectra changed only slightly in the 294-320 nm range with respect to time and temperature. high performance ...19863763167
isolation of a neurotoxin from the salivary glands of female rhipicephalus evertsi evertsi.a quantitative study of the changes in the protein pattern of the salivary glands of female rhipicephalus evertsi evertsi during the entire repletion process was undertaken. these results, in conjunction with the previously determined toxic phase, indicated the presence of a toxic protein. the development of a sensitive in vitro assay using a xenopus nerve-muscle preparation, made it possible to identify toxic phases during feeding and to assay fractions of salivary gland extracts during toxin i ...19863819963
[investigations on the influence of temperature and relative humidity on development and survival of rhipicephalus evertsi evertsi neumann, 1897 (author's transl)]. 19744833627
[efficacy of the paraimmunity inducer pind-avi in rhipicephalus evertsi evertsi infestations in sheep: current perspectives in tick control and the prevention of tick paralysis]. 19846720165
[physiopathology of rhipicephalus evertsi evertsi neumann, 1897, induced tick paralysis of sheep]. 19836847597
[sectional classification of the toxicity of the paralysis-inducing female rhipicephalus evertsi evertsi neumann, 1897, during repletion]. 19827090645
[antitoxic immunity in rhipicephalus evertsi evertsi-paralysis in sheep]. 19827090650
[action potentials and conduction velocities of the tibial nerve in sheep paralysis caused by rhipicephalus evertsi evertsi]. 19827113523
parasites of domestic and wild animals in south africa. xxxi. adult ixodid ticks on sheep in the cape province and in the orange free state.four to 10 dorper sheep on each of 12 farms in the cape province and 3 farms in the orange free state were examined for adult ixodid ticks at approximately 2- to 4-weekly intervals over periods varying from 4 to 18 months, commencing during january, february or april 1989. the farms in the cape province were located in the north-west, south-west and south of the province. those in the orange free state were situated in the north-east and in the south. the sheep in the cape province harboured 10 ...19921297957
[plasma lysozyme activity in tick paralysis of sheep caused by rhipicephalus evertsi evertsi]. 19827201794
[neurophysiopathology of rhipicephalus evertsi evertsi paralysis]. 19817282181
[histology of the foveal glands in rhipicephalus evertsi evertsi neumann, 1897]. 19817337651
parasites of domestic and wild animals in south africa. xxx. ectoparasites of kudus in the eastern transvaal lowveld and the eastern cape province.sets of four kudus were shot and examined for arthropod parasites at approximately monthly intervals from april 1981 to march 1983 in the southern part of the kruger national park, eastern transvaal lowveld. these animals harboured 10 ixodid tick species of which boophilus decoloratus followed by amblyomma hebraeum were the most abundant. the seasonal abundances of these ticks and of amblyomma marmoreum, rhipicephalus appendiculatus, rhipicephalus evertsi evertsi and rhipicephalus zambeziensis w ...19921297956
life cycle of the tick rhipicephalus evertsi evertsi neumann (acarina: ixodidae) under laboratory conditions.the preoviposition period of the tick rhipicephalus evertsi neumann maintained under laboratory conditions at 26 c was 6.1 +/- 0.38 days. the average number of eggs produced during the oviposition period was 10,400 +/- 397 (max. 13.307, min. 7,558). the greatest daily egg production was recorded on the 3rd day (1.107 eggs/female). the incubation period of eggs at 26 c was 24.8 +/- 1.37 and the feeding time of the larvae and nymphs (a two-host tick) was 17.2 +/- 0.14 days at 26 c. this tick repre ...1977864575
the life cycle of the two-host tick rhipicephalus evertsi evertsi neumann, 1897, under laboratory conditions (acarina: ixodidae).the life cycle of rhipicephalus evertsi evertsi neumann, 1897, is discussed under the following headings: larval feeding; larval drop; nymphal feeding; nymphal drop; nymphal moulting; adult feeding; adult drop; preoviposition period; oviposition period and incubation. special attention has also been given to the development of both male and female reproductive organs, gametogensis and mating.1977614518
the effect of host resistance on the metabolic rate of engorged females of rhipicephalus evertsi evertsi.this study investigated the effect of acquired resistance in guinea-pigs on the metabolic rate of adult females of the tick rhipicephalus evertsi evertsi. guinea-pigs were subjected to three successive infestations of ticks and the rate of co2 production (vco2) measured in first and third infestation engorged females. ticks which fed on resistant hosts showed a 52% decrease in mass compared to ticks that fed on naive animals. reduction in mass was accompanied by a decrease in vco2 (mlh-1) per ti ...19957548947
the effects of tick numbers and intervals between infestations on the resistance acquired by guinea-pigs to adults of rhipicephalus evertsi evertsi (acari: ixodidae).guinea-pigs were infested three times at short (1 week) intervals or long (10 week) intervals between successive infestations with low (1), medium (8) and high (15) numbers of adult rhipicephalus evertsi evertsi. to compare the resistance developed by the hosts at short and long intervals between infestations, a challenge (fourth) infestation was performed with the high number of ticks. resistance was assessed by comparing the mean weight of engorged female ticks that dropped from the hosts. con ...19947555412
the localization of a paralysis toxin in granules and nuclei of prefed female rhipicephalus evertsi evertsi tick salivary gland cells.a monoclonal antibody directed against a paralysis toxin of rhipicephalus evertsi evertsi ticks was used to localize the toxin in cytoplasmic granules and, surprisingly, chromatin of the nuclei of cells which resemble the "b" cell type in the salivary glands of rhipicephalus appendiculatus, boophilus microplus and ixodes holocyclus. the association of toxin with chromatin indicates that the toxin may have a regulatory function. evidence is provided to support the view that the toxin is made up o ...19937628232
investigations into lymphocyte transformation and histamine release by basophils in sheep repeatedly infested with rhipicephalus evertsi evertsi ticks.the immune response of a natural host of rhipicephalus evertsi evertsi to feeding by this tick species was investigated with respect to the effects of tick salivary gland extracts on the transformation of peripheral blood lymphocytes and the release of histamine by basophils obtained from repeatedly infested sheep. the results indicated that there was no stimulation of lymphocyte transformation but that histamine release was elevated 10 fold after four infestations. although this suggests a hype ...19937628233
[descriptive epidemiology of bovine theileriosis caused by theileria annulata in mauritania, subsaharian west africa].tropical bovine theileriosis due to theileria annulata has been discovered recently in mauritania. an epidemiological study performed in the dry season allowed to better determine the serological prevalence of t. annulata infection and its associated factors. the sex does not seem to have any influence, the role of the breed could not be clearly established, whereas, the age, the geographical origin and the management of the herd have a significant influence on the serological prevalence. these ...19947863061
tick infestations on zebu cattle in western kenya: individual host variation.monthly collections were made of all ticks from 25 mature east african zebu cattle and 5 yearlings for 13 mo on rusinga island, lake victoria, kenya, from september 1986 to september 1987. the most common species were rhipicephalus appendiculatus neumann and amblyomma variegatum f.; boophilus decoloratus koch and rhipicephalus evertsi evertsi neumann also were present in fewer numbers. cattle were ranked according to their degree of resistance to each of the four species and to each stage in the ...19912033602
[ticks and hemoparasitoses of livestock in senegal. vi. the soudano-sahelian zone].the authors report the results of a study on ticks and hemoparasitoses among cattle, sheep and goats in the sudano-sahelian zone. during a period of 15 months, ticks were systematically removed from 40 cattle, 40 sheep and 40 goats in order to assess the population dynamics and determine more accurately the preferential sites of settlement of the different species. the following species were collected in ruminants: hyalomma truncatum, h. marginatum rufipes, rhipicephalus evertsi evertsi, rh. gui ...19947991897
[crimean-congo hemorrhagic fever in senegal. latest data on the ecology of the cchf virus].the authors finalize the knowledge on the ecology of the cchf virus in senegal, west africa. they specify two new major data for the understanding of the viral ecology in west africa. the recognition of a bird species, common and widely distributed in senegal (tockus erythrorhynchus, coraciiformes, bucerotidae), that replicates the virus and infects the immature stages of its current parasite hyalomma marginatum rufipes in more than 90% of the cases, explains why the minimum infection rate of th ...19948003897
control of tsetse flies in uganda by dipping cattle in deltamethrin.the effect of treating cattle with deltamethrin to control tsetse flies and ticks was investigated on 2 ranches 8 km apart in central uganda where there is a high risk of trypanosomosis. this area had a moderate challenge of glossina pallidipes. the cattle had very low challenge of rhipicephalus appendiculatus, amblyomma variegatum, boophilus decolaratus and rhipicephalus evertsi evertsi, due to regular treatment with dioxathion. on one ranch a dip was charged with deltamethrin to treat cattle r ...19948009646
development of resistance in laboratory animals to adults of the tick rhipicephalus evertsi evertsi.acquired resistance to adults of the two-host tick rhipicephalus evertsi evertsi neumann has been demonstrated in guinea-pigs and rabbits. four infestations of both hosts with r.e.evertsi adults resulted in a significant reduction in the mean weight of the engorged females. a decline in the mean weight of the female ticks was also observed in ticks which fed on a rabbit previously injected with serum taken from a rabbit resistant to r.e.evertsi. this suggests that humoral immunity may have an im ...19911768898
prevalence of rickettsia-like organisms and spotted fever group rickettsiae in ticks (acari: ixodidae) from zimbabwe.the prevalence of rickettsia-like organisms in ticks from zimbabwe was determined using the hemolymph test. amblyomma hebraeum had the highest prevalence of rickettsia-like organisms. other species with rickettsia-like organisms included amblyomma sparsum, amblyomma variegatum, hyalomma marginatum rufipes, ripicephalus simus, haemaphysalis leachi, amblyomma rhinocerotis, and hyalomma truncatum. ticks with no demonstrable rickettsia-like organisms infection were boophilus decoloratus, haemaphysal ...19958551500
the effects of non-specifically activated immunity in rabbits on primary infestation with rhipicephalus evertsi evertsi.the secondary antibody response to sheep red blood cells and bovine serum albumin (bsa) was measured in rabbits infested with adult rhipicephalus evertsi evertsi. the response was reduced (particularly for bsa) but still displayed anamnestic characteristics. resistance against ixodid ticks associated with antibodies detected by gel diffusion and enzyme linked immunosorbent assay techniques early in the primary challenge was acquired by the immunized hosts only. this suggests that a non-specifica ...19902345953
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 ...19968746132
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 ...19968834737
the identification of a shared immunogen present in the salivary glands and gut of ixodid and argasid ticks.the identification of a 70-kda immunogen present in salivary gland extracts of several ixodid species, namely hyalomma truncatum (sweating-sickness-inducing (ss+) and non-inducing (ss-) strains), hyalomma marginatum rufipes and rhipicephalus evertsi evertsi, is reported. the immunogen was identified by western blots using a monoclonal antibody of the igm isotype directed against a 70-kda immunogen present in the salivary glands of (ss-) female h. truncatum ticks. cross-reactivity with the gut of ...19921446571
detection of theileria annulata by the pcr in ticks (acari:ixodidae) collected from cattle in mauritania.we report on the detection of theileria annulata in infected hyalomma ticks by the pcr using primers derived from the gene encoding the 30 kda major merozoite surface antigen (tamsi-1). no inhibition of the pcr was observed and as little as 0.1 pg of parasite dna, corresponding to 12 sporozoites, could be detected in non-infected tick dna samples, spiked with t. annulata genomic dna. hyalomma dromedarii ticks, fed on a calf experimentally infected with t. annulata, were used to validate the pcr ...19979203350
a sero-epidemiological survey of equine piroplasmosis in the northern and eastern cape provinces of south africa.serum samples from yearling thoroughbred horses (n = 176) in the magisterial districts of colesberg, venterstad, and wodehouse in the northern and eastern cape provinces were collected between september and november 1995 to determine the prevalence of antibodies to babesia equi and babesia caballi in these regions. samples were examined for specific antibodies using the indirect fluorescent antibody test. the 95% confidence intervals for the prevalence of serum antibodies in the 3 districts comb ...19969284032
evidence to show that an agent that cross-reacts serologically with cowdria ruminantium in zimbabwe is transmitted by ticks.the serological diagnosis of heartwater based on reactions to the immunodominant cowdria ruminantium major antigen protein-1 (map-1) is impaired by the detection of false-positive reactions. in this study, the prevalence of false-positive reactions on seven heartwater-free farms in zimbabwe was determined to be 8-94% by immunoblotting against c. ruminantium antigens. the highest prevalence of false-positives on spring valley farm correlated with the presence of rhipicephalus evertsi evertsi tick ...19989493330
the effects of nutritional status of rabbits and sheep on their resistance to the ticks rhipicephalus evertsi evertsi and r. appendiculatus.rabbits and sheep were exposed to low- and high-protein diets and subsequently infested three times with adults of rhipicephalus appendiculatus and rhipicephalus evertsi evertsi. the mean weight of r.e. evertsi females which dropped from rabbits maintained on a high-protein diet decreased from 515.0 +/- 24.9 mg (naive) to 381.5 +/- 25.0 (second infestation) to 340.3 +/- 23.3 mg (third infestation) while the weight of ticks fed on animals which were exposed to a low-protein diet did not change si ...19921446570
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 ...19827177586
investigations into the paralysis-inducing ability of rhipicephalus evertsi mimeticus and that of hybrids between this subspecies and rhipicephalus evertsi evertsi.studies performed on sheep showed that rhipicephalus evertsi mimeticus is a paralysis-competent tick species whose toxicity is either the same as, or only slightly less than that of r.e. evertsi. it was also proved that the paresis or paralysis induced by the mimeticus females is characterized by a constant incubation period which is independent of the tick infestation rate and body mass of the host, and consequently of its age. this period is entirely determined by the state of repletion of the ...19863960488
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 ...19989741055
tick diversity, abundance and seasonal dynamics in a resource-poor urban environment in the free state province.the objectives of this study were to determine the diversity, seasonal dynamics and abundance of ticks infesting cattle in urban, small-scale farming communities in and around botshabelo and thaba nchu in the eastern free state province, south africa. a total of ten cattle, ear-tagged for individual identification, were investigated monthly at each of five localities. adult ticks were removed from the right hand side of each animal and placed in containers filled with 70% ethanol. they were subs ...199810192844
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 ...199910353189
[experimental transmission of crimean-congo hemorrhagic fever virus by rhipicephalus evertsi evertsi (acarina:ixodidae)].we have conducted experiments to assess the ability of rhipicephalus evertsi evertsi tick to transmit the crimean-congo haemorrhagic fever (cchf) and determine their reproductive cycle. the rh. e. evertsi was infected by intracoelomic (transparietal and intra-anal) inoculation during the imaginal stases and by oral feeding on an infected viremic goat during imaginal and nymphal stases. the infection rate, transovarial and trans-stasial cchf virus transmission were monitored for virus reisolation ...199910472436
studies on the ability of different strains or populations of female rhipicephalus evertsi evertsi (acarina:ixodidae) to produce paralysis in sheep.simultaneous infestation of 3-6 month-old black-head sheep with 15 south african wild strains of rhipicephalus evertsi evertsi males and females as well as a strain from rwanda clearly showed that all strains are capable of inducing paralysis. assessment of the infestation-rate of engorging female ticks during the period that their mass ranged between 15 and 21 mg/kg sheep body mass indicated that toxicity is quantitatively identical and exhibits no intraspecific gradations. the period between t ...19863960487
[the mechanics of oviposition in rhipicephalus evertsi evertsi neumann, 1897]. 19873593192
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 ...200111403429
influence of sheep breed and application site on the efficacy of a flumethrin pour-on formulation against ticks.the objectives of this study were to determine the influence of application site and sheep breed on the efficacy of a flumethrin (1% m/v) solution for the control of 'bont'-legged (hyalomma spp.) and red-legged ticks (rhipicephalus evertsi evertsi). this study was conducted from november 1996 to february 1997 on 3 farms in the southwestern free state province. two trials were conducted on dorper sheep and 2 on merino sheep. for each specific application 30 sheep were selected and allocated to 3 ...200111811701
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 ...200112026058
ixodid ticks on indigenous goats owned by small-scale farmers in four communal grazing areas in south africa.indigenous goats belonging to small-scale farmers in 4 communal grazing areas in south africa were sampled for ixodid ticks during the period september 1991 to may 1993. three of these areas were in the north west province (rietgat, madinyane and bethany), and one in mpumalanga province (geluk). no tick control was practised unless requested by the owners. seven ixodid tick species, of which the majority were immature ticks, were collected from the goats in north west province. amblyomma hebraeu ...200212088070
seasonal abundance of adult ixodid ticks infesting cattle belonging to resource-limited farmers in the north-eastern free state province of south africa.a study was undertaken to determine the seasonal abundance of the ticks infesting cattle owned by resource-limited farmers in the north-eastern free state province of south africa. infestations of boophilus decoloratus koch, 1844, rhipicephalus evertsi evertsi neumann, 1897, rhipicephalus follis donitz, 1910, rhipicephalus gertrudae feldman-muhsam, 1960 and rhipicephalus warburtoni walker & horak, 2000, were monitored on cattle of mixed breeds at monthly intervals from may 1998 to april 1999. hi ...200212092776
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 ...200212515294
seasonal fluctuation of parasitic infestation in donkeys (equus asinus) in oodi village, kgatleng district, botswana.during the period march to september 2000, a study was conducted in oodi village, kgatleng district, botswana, to investigate the seasonal fluctuation of internal, external and blood parasites of donkeys. twelve adult donkeys were randomly selected from a farmer with a herd of 15 donkeys. monthly visits were made to the farmer when the donkeys were examined for parasites. the only ectoparasites recovered from the donkeys were instars of various tick species. the most prevalent tick was rhipiceph ...200312836744
ticks and tick-borne diseases of livestock belonging to resource-poor farmers in the eastern free state of south africa.the paper provides a summary of three studies conducted in the eastern free state of south africa between 1998 and 2000. in a questionnaire-based study approximately 21% of interviewed resource-poor farmers (n = 150) indicated that they experienced problems with ticks and tick-borne diseases. about 56% of farmers indicated that tick-related problems were most severe in summer, while 32% indicated that the most problems were encountered in winter. about 12% indicated that the tick problems were e ...200214570134
a sero-epidemiological survey of blood parasites in cattle in the north-eastern free state, south africa.a survey to determine the incidence of parasites in cattle (n = 386) was conducted in the north eastern free state between august 1999 and july 2000. giemsa-stained blood smears were negative for blood parasites. a total of 94% of the cattle were sero-positive for babesia bigemina by indirect fluorescent antibody test while 87% were sero-positive for anaplasma by enzyme-linked immunosorbent assay. the observation of negative blood smears but high incidence of positive serological results for ana ...200415185577
crimean-congo hemorrhagic fever, mauritania.from february to august 2003, 38 persons were infected with crimean-congo hemorrhagic fever (cchf) virus in mauritania; 35 of these persons were residents of nouakchott. the first patient was a young woman who became ill shortly after butchering a goat. she transmitted the infection to 15 persons in the hospital where she was admitted and four members of her family. in nouakchott, two disease clusters and 11 isolated cases were identified. the case-fatality ratio was 28.6%. of the patients not i ...200415663851
relationship between ticks and zebu cattle in southern uganda.tick populations were observed on zebu (bos indicus) cattle over a period of 2 years at entebbe, uganda where the climate was thought to be highly favourable for the free-living stages of ticks. collections of all instars of ticks were made from the body surfaces of the cattle at intervals of between 1 and 5 weeks. the species recorded in order of decreasing abundance were rhipicephalus appendiculatus, amblyomma variegatum, boophilus decoloratus, rhipicephalus evertsi evertsi, rhipicephalus simu ...19827101465
transstadial and intrastadial experimental transmission of ehrlichia canis by male rhipicephalus sanguineus.the acquisition and transmission of rickettsial pathogens by different tick developmental stages has important epidemiological implications. the purpose of this study was to determine if male rhipicephalus sanguineus can experimentally acquire and transmit ehrlichia canis in the absence of female ticks. two trials were performed where nymphal and male r. sanguineus were simultaneously acquisition fed on the same infected donor hosts, and transstadially or intrastadially exposed male ticks were f ...200515941624
detection of babesia canis rossi, b. canis vogeli, and hepatozoon canis in dogs in a village of eastern sudan by using a screening pcr and sequencing methodologies.babesia and hepatozoon infections of dogs in a village of eastern sudan were analyzed by using a single pcr and sequencing. among 78 dogs, 5 were infected with babesia canis rossi and 2 others were infected with b. canis vogeli. thirty-three dogs were positive for hepatozoon. hepatozoon canis was detected by sequence analysis.200516275954
some observations on ticks (acari: ixodidae) infesting sheep in river nile province of northern sudan.five species of ixodid ticks were found in a cross-sectional survey in which 200 sheep were examined for ticks in river nile province, sudan. hyalomma anatolicum anatolicum was the predominant species (73.6%), whereas ticks belonging to the rhipicephalus sanguineus group (14.7%), rhipicephalus evertsi evertsi (9.1%), rhipicephalus simus (2%) and hyalomma dromedarii (0.5%) were also found. the mean tick load was 11.2 per animal. in a subsequent longitudinal survey ticks were collected on a monthl ...200516300192
acaricide efficiency of amitraz/cypermethrin and abamectin pour-on preparations in game.the efficacy of an amitraz/cypermethrin pour-on preparation (1% w/v each) was tested against natural tick infestations of buffaloes, eland and blesbok in three separate trials. the eland were also treated with a 0.02% abamectin (w/v) acaricidal pour-on preparation. the amitraz/cypermethrin pour-on was effective against amblyomma hebraeum, rhipicephalus evertsi evertsi, rhipicephalus appendiculatus and hyalomma marginatum rufipes on the buffaloes. both acaricides were effective against r. appendi ...200516562734
investigation into the participation of male pheromones of rhipicephalus evertsi evertsi during infestation.it was shown in this study that rhipicephalus evertsi evertsi males emit pheromones in the preparasitic as well as in the parasitic phases. conspecific unengorged male and female images exhibited a high response to water-soluble volatiles collected from unengorged males. a vigorous assembly of unfed female r. evertsi evertsi occurred on filter paper discs which had been in contact with either unfed or 5- and 9-day fed males. progressively increasing percentages of conspecific unengorged males re ...19854047618
immunological responses and the role of the paralyzing toxin in rabbits infested with rhipicephalus evertsi evertsi.twenty-nine rabbits were exposed to 4 infestations with 20, 50, and 100 adult red-legged ticks (rhipicephalus evertsi evertsi). upon challenge, 16 rabbits (55%) contracted paralysis, and 14 of these (88%) died. most deaths occurred in rabbits challenged with 100 ticks. immunity to paralysis and subsequent resistance to tick feeding developed in the hosts that survived the initial challenge. antibody titers to a salivary gland antigen increased progressively as determined by the following tests: ...19863789273
ehrlichia ruminantium variants which do not cause heartwater found in south africa.in 1994 a batch of apparently healthy goats was selected for intended export to the usa from a heartwater-free and vector tick-free region of south africa. the animals were tested serologically for heartwater, using either or both an ifa and an elisa test, and 52% were found to be serologically positive. a pcr assay based on ehrlichia ruminantium 16s gene sequences gave positive results for 54% of the animals, suggesting that apparently non-pathogenic e. ruminantium variants existed in this hear ...200717123750
detection of rickettsia africae in rhipicephalus (boophilus) decoloratus ticks from the republic of botswana, south africa.a total of 53 engorged adult ticks belonging to the species rhipicephalus (boophilus) decoloratus (n = 9), rhipicephalus evertsi evertsi (n = 27), rhipicephalus appendiculatus (n = 9), amblyomma hebraeum (n = 5), and hyalomma marginatum turanicum (n = 3), were removed from oryx in botswana (south africa). they were tested for the presence of spotted fever group (sfg) rickettsia and anaplasma phagocytophilum using polymerase chain reaction (pcr). seventy-seven percent of r. decoloratus as well as ...200717690416
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 ...200717708147
kinetic properties of toxic protease inhibitors isolated from tick eggs.1. egg-toxins from rhipicephalus evertsi evertsi, boophilus microplus, boophilus decoloratus and hyalomma truncatum were found to be inhibitors of trypsin and in two cases also of chymotrypsin. 2. fast tight-binding and slow-binding inhibition were observed. 3. immunological identity of the toxins were assessed with ouchterlony immunodiffusion and elisa. 4. the protease content of b. decoloratus and amblyomma hebraeum tick eggs were determined by a linked enzyme assay. 5. the predictive value of ...19883391338
distribution and population dynamics of ticks (acari: ixodidae) infesting sheep in sennar state, sudan.a cross-sectional survey of ticks infesting sheep was conducted in sennar state, sudan. a total body collection of ticks was carried out at five localities sennar town, singa, dinder, abu naama and um banein on two types of desert sheep (watish and ashgar) on two farms at each locality at two monthly intervals for one year starting july 2002 to may 2003. four tick genera and eight species were identified. they were amblyomma lepidum, hyalomma anatolicum anatolicum, hyalomma truncatum, rhipicepha ...200718453239
identification of a novel babesia sp. from a sable antelope (hippotragus niger harris, 1838).babesiosis in a sable antelope (hippotragus niger harris, 1838) was first reported in 1930; the parasite was named babesia irvinesmithi. recently, specimens from an adult sable that presented with a sudden onset of disease and that subsequently died during immobilization were submitted for molecular characterization. microscopic examination of thin blood smears revealed the presence of small piroplasms. dna was extracted from blood samples; the v4 variable region of the 18s rrna gene was amplifi ...200818508943
reliminary survey of ticks (acari: ixodidae) on cattle in central equatoria state, southern sudan.in a preliminary survey conducted in 2005, the species composition and seasonality of ticks infesting cattle in central equatoria state, southern sudan was determined. three locations were selected (gumbo, khor rumla and nyaing) and surveyed every 3 months. two cattle herds in each of the three locations were visited four times during the study period. total body collections of ticks were made from each of five cattle (nilotic zebu breed) kept in six different herds. four tick genera and ten spe ...200818575063
acquired resistance in rabbits to immature stages of rhipicephalus evertsi evertsi.host resistance, accompanied by demonstrable anti-tick antibodies, developed in groups of rabbits that were infested repeatedly with different numbers of rhipicephalus evertsi evertsi larvae. this resistance was associated with a drastic reduction in the number of ticks that attached but not in the ability to feed and moult by immatures already established on the hosts. furthermore, resistance reduced to below 50% the proportion of nymphs which emerged from the larvae applied to the three host g ...19883195049
adult ixodid ticks on two cattle breeds in the south-western free state, and their seasonal dynamics.a study was conducted to compare the species of adult ixodid ticks on friesian and bonsmara cattle and their seasonal dynamics. between five and ten animals of each breed were kept on natural false upper karoo vegetation, typical of the south-western free state. between may 1990 and october 1991, the animals were examined once or twice a month for the presence of adult ticks which were removed, counted and identified. six species of ixodid ticks were recorded. the species composition on the two ...19968848299
host surveys, ixodid tick biology and transmission scenarios as related to the tick-borne pathogen, ehrlichia canis.the ehrlichioses have been subject to increasing interest from veterinary and public health perspectives, but experimental studies of these diseases and their etiologic agents can be challenging. ehrlichia canis, the primary etiologic agent of canine monocytic ehrlichiosis, is relatively well characterized and offers unique advantages and opportunities to study interactions between a monocytotropic pathogen and both its vertebrate and invertebrate hosts. historically, advances in tick-borne dise ...200818963493
ixodid ticks infesting domestic goats in communal land areas of zimbabwe.the purpose of this study was to determine the species spectrum of ticks infesting goats owned by resource-limited farmers in the state-owned communal land areas of zimbabwe. ticks were collected from goats at a single locality within each of 5 communal land areas, and a total of 14 ixodid tick species was recovered. the most numerous tick was rhipicephalus evertsi evertsi, which was present in all areas at each sampling, and a rhipicephalus sp. (near r. punctatus), which was most abundant on go ...200819244819
parasites of domestic and wild animals in south africa. xxvi. the mosaic of ixodid tick infestations on birds and mammals in the mountain zebra national park.sixteen species of ixodid ticks were collected over varying periods of time from 6 species of ground-frequenting birds and 15 species of small and large mammals in the mountain zebra national park, karoo, cape province. margaropus winthemi followed by rhipicephalus glabroscutatum and rhipicephalus evertsi evertsi were the most abundant species. the host preferences of 14 tick species and the seasonal abundances of 13 species were determined. small numbers of immature stages of only a few tick sp ...19911923374
coxiella burnetii in humans and ticks in rural senegal.q fever is a worldwide zoonotic disease caused by coxiella burnetii. epidemiologically, animals are considered reservoirs and humans incidental hosts.201020386603
survey of ixodid ticks in domestic ruminants in bedelle district, southwestern ethiopia.a survey aimed at determining the status of ticks in cattle, sheep and goats in bedelle district (southwestern ethiopia) was carried out from november 2007 to april 2008. out of the total 330 animals examined, 314 (95.2%) were found to be infested (harbouring of at least a single tick). high rates of infestations were recorded across all three host species. factors like month of collection, age and sex of host species did not show significant association with infestation rates. a total of 5,507 ...201020563884
bm86 homologues and novel ataq proteins with multiple epidermal growth factor (egf)-like domains from hard and soft ticks.tick control on livestock relies principally on the use of acaricides but the development of acaricide resistance and concerns for environmental pollution underscore the need for alternative control methods, for instance through the use of anti-tick vaccines. two commercial vaccines based on the recombinant bm86 protein from rhipicephalus (boophilus) microplus ticks were developed. partial protection of the bm86 vaccine against other rhipicephalus (boophilus) and hyalomma tick species suggests t ...201020647015
parasites of domestic and wild animals in south africa. xxv. ixodid ticks on sheep in the north-eastern orange free state and in the eastern cape province.the tick burdens of 115 merino sheep, slaughtered over a period of 15 consecutive months on a farm in the north-eastern orange free state, were determined. a total of 7 ixodid and 1 argasid tick species were recovered and the seasonal abundances of boophilus decoloratus, hyalomma marginatum rufipes, margaropus winthemi and rhipicephalus evertsi evertsi were determined. one hundred and forty-nine merino sheep were slaughtered over periods varying from 10 to 25 months on 3 farms in eastern provinc ...19911923373
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 ...19807452655
tick-borne rickettsioses, neglected emerging diseases in rural senegal.rickettsioses are one of the most important causes of systemic febrile illness among travelers from developed countries, but little is known about their incidence in indigenous populations, especially in west africa.201020856858
[toxic phase of the paralysis-inducing female rhipicephalus evertsi evertsi neumann, 1897, during repletion]. 19807456907
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, ...200921105593
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