| electron microscopic studies on the development of kinetes of theileria parva theiler, 1904 in the gut of the vector ticks rhipicephalus appendiculatus neumann, 1901. | the development of motile stages, called kinetes, from a stationary stage (regarded as zygote) has been followed in theileria parva by means of electron miscroscopy. this process started after moult of the tick nymphs which had sucked on highly infected calves, i.e. about 20 days after repletion (a.r.) of the ticks. the transformation took place by formation of a growing protrusion (= anlage) into an inner, enlarging vacuole. during this process the limiting membrane of the enlarging vacuole ser ... | 1978 | 28653 |
| effect of humoral antibodies on the course of theileria parva infection (east coast fever) of cattle. | a study was made of the effects of serum and gamma-globulins from vaccinated cattle (donor cattle) given to cattle (principals) exposed to theileria parva infection (east coast fever (ecf)). the principals were treated with normal serum, with serum containing high antibody titer against t parva (as evaluated by the indirect fluorescent antibody (ifa) technique), or with globulins prepared from normal and from immune serums. for exposure, the principals were inoculated with standardized suspensio ... | 1975 | 47727 |
| rapid quantitative assessment of theileria infection in ticks. | a simplified method for methyl green pyronin staining is described for theileria parva and t. annulata in whole salivary glands of rhipicephalus appendiculatus and hyalomma anatolicum subspecies respectively. the stain gives results comparable with feulgen staining and can be used after the ticks have been in cold storage for 3 days. there is considerable variability in the rate and intensity of infection of these ticks with theilerial parasites and it is concluded that the method permits large ... | 1979 | 87045 |
| histopathologic and electron microscopic studies of cutaneous lesions in calves with experimentally induced east coast fever (theileriosis). | skin lesions of bovine east coast fever were examined by light and electron microscopy at 120 hours after attachment of rhipicephalus appendiculatus ticks infected with theileria parva. lesions included epidermal ulcer, hemorrhage, edema, necrosis, and inflammatory cell infiltration by mostly polymorphonuclear and mononuclear (lymphoid) cells. the trophozoite state of t parva was observed in a parasitophorous vacuole and feeding on neutrophil granules. schizonts, some in budding process, and mer ... | 1978 | 98077 |
| induction of infective stages of theileria parva by exposure of host ticks to high temperature. | it was demonstrated that theileria parva parasites infective to cattle could be induced by exposure of infected adult rhipicephalus appendiculatus ticks to 37 degrees c. the production of the sporozoites of t parva was not as efficient as by feeding ticks on rabbits. | 1979 | 119344 |
| the differential diagnosis of the bovine theilerias of southern africa. | it is currently thought that the following species or sub-species of theileria occur in cattle in southern africa: theileria parva parva (east coast fever), theileria parva lawrencei (corridor disease), theileria parva bovie (rhodesian theileriosis), theileria mutans proper (transmitted by amblyomma species), so-called theileria mutans (a non-pathogenic species transmitted by rhipicephalus appendiculatus, possibly identical with theileria taurotragi) and theileria velifera. the parasites can be ... | 1979 | 122000 |
| artificial infection of the tick rhipicephalus appendiculatus with theileria parva. | methods for infecting rhipicephalus appendiculatus ticks with theileria parva by injection and by artificial feeding were confirmed and compared. the injection method proved simpler and at best as effective and suggested improvements are described. | 1979 | 122269 |
| isolation of a theileria species from eland (taurotragus oryx) infective for cattle. | theileria infections were induced in cattle by feeding ticks on them from 3 sources: (a) adult rhipicephalid ticks obtained from the vegetation in a paddock containing an eland eao at the animal orphanage, nairobi national park, kenya, (b) rhipicephalus appendiculatus adults fed as nymphs on the same eland, (c) r. pulchellus adults fed as nymphs on an eland w 68 captured in the machakos district of kenya. both eland were harbouring theileria parasites at the time nymphal ticks were fed. mild inf ... | 1977 | 407683 |
| studies on theileriidae (sporozoa) in tanzania ix. unidentified bovine theileriae. | two strains of nonpathogenic theileriae, designated as theileria sp. (idobogo) and theileria sp. (mwanza), were isolated from cattle in southern and northern tanzania respectively. they were similar to each other, producing low numbers of t. parva-like macroschizonts and of small piroplasms. both were readily transmitted by rhipicephalus appendiculatus. no serological relationship with t. mutans was found, while serum of some of the recovered animals gave fleeting, low titres in the indirect flu ... | 1977 | 414387 |
| theileria parva piroplasmosis in mice, and its attempted transmission with rhipicephalus appendiculatus ticks. | theileria parva piroplasm infection of mouse erythrocytes was detected, following intraperitoneal inoculation of mice with irradiated cultures of t. parva-infected bovine lymphoid cells. infection could not be transmitted to cattle using rhipicephalus appendiculatus ticks. | 1977 | 414389 |
| development of theileria parva (theiler, 1904) in the gut of rhipicephalus appendiculatus (neumann, 1901). | | 1977 | 415285 |
| parasites of domestic and wild animals in south africa. xiii. the seasonal incidence of adult ticks (acarina: ixodidae) on cattle in the northern transvaal. | ticks were collected over a period of 13 months, at approximately fortnightly intervals, from 6 africaner oxen kept on the farm nylsvley in the naboomspruit district. the 8 species of ixodidae collected were, in order of abundance, rhipicephalus appendiculatus, r. evertsi evertsi, hyalomma marginatum rufipes, h. truncatum, amblyomma hebraeum, r. simus, boophilus decoloratus and ixodes cavipalpus. the relative abundance of adult ticks of these species, their predilection feeding sites and seasona ... | 1979 | 460821 |
| the use of frequency diagrams in the survey of resistance to pesticides in ticks in southern africa. | a method whereby resistance data can be analysed by means of frequency distributions is described. this method established that rhipicephalus appendiculatus and r. evertsi evertsi show either little or only developing resistance to the pesticides chlorfenvinphos and dioxathion. boophilus spp., however, show more instances and higher levels of resistance to these 2 pesticides. | 1979 | 551365 |
| tick infestations and tick-borne diseases in zimbabwe rhodesia. | the distribution of tick species in zimbabwe rhodesia is significantly influenced by land utilization practices. the most commonly occurring species in the over-grazed tribal areas is boophilus decoloratus. by contrast, well-managed commercial farms and ranches support a wide range of tick species, the most important of which is rhipicephalus appendiculatus. until recently tick-borne diseases of cattle were efficiently controlled through dipping. the low incidence of disease was an important fac ... | 1979 | 553966 |
| a survey of nairobi sheep disease antibody in sheep and goats, wild ruminants and rodents within kenya. | the distribution of antibody to nairobi sheep disease in sheep and goats in kenya was found to coincide closely with that of the tick, rhipicephalus appendiculatus. the proportions of a population in an enzootic area with antibody was similar in the different age groups. no antibody to the virus was found in rodent sera and while some low titres were found in some wild ruminant sera, these were considered to be most likely cross reactions with antibody to related viruses. | 1978 | 701789 |
| nairobi sheep disease in kenya. the isolation of virus from sheep and goats, ticks and possible maintenance hosts. | nairobi sheep disease was seen principally upon movement of susceptible animals into the enzootic areas. this occurred most frequently for marketing purposes near the main centres of population. other outbreaks followed local breakdowns in tick control measures. the disease did not occur in epizootic form during the period under consideration. nairobi sheep disease was isolated from pools of rhipicephalus appendiculatus but not from many pools of other tick species. no virus was isolated from th ... | 1978 | 701790 |
| investigations on a theileria species from an impala. | an immature impala (aepyceros melampus), captured in the machakos district of kenya, had theileria-like parasites in its erythrocytes. blood from this animal was inoculated into a theileria-free impala born in captivity and a theileria-free, splenectomized steer. theilerial piroplasms were detected in the erythrocytes of the recipient impala 10 days after inoculation, and a peak parasitaemia of 2% was reached after 48 days, but no infection was detected in the steer. anaemia developed in the rec ... | 1975 | 803575 |
| the role of wild mammals in the epidemiology of bovine theilerioses in east africa. | the theileriidae of east african wild mammals are reviewed. three species of wild bovidae were captured in east africa. they were africa cape buffalo (syncerus caffer), blue wildebeest (connochaetes taurinus) and eland (taurotragus oryx), and all were found to be naturally infected with theileria species. these animals were studied to determine the transmissibility and pathogenicity of their theilerial infections to cattle. adult rhipicephalus appendiculatus ticks, which had engorged as nymphs o ... | 1975 | 803580 |
| development of theileria mutants (aitong) in the tick amblyomma variegatum compared to that of t. parva (muguga) in rhipicephalus appendiculatus. | a comparison was made between the development of theileria mutans (aitong) in adult amblyomma variegatum ticks and the development of t. parva (muguga) in adult rhipicephalus appendiculatus ticks. both batches of ticks dropped as engorged nymphs from cattle whose intraerythrocytic parasitemias were approximately 40%, and it was thus possible to make a direct comparison of the infection rates produced in their tick hosts in this experiment by the 2 species of theileria. ticks of the 2 batches wer ... | 1975 | 809568 |
| correlation between the morphology and infectivity of theileria lawrencei developing in the tick rhipicephalus appendiculatus. | adult rhipicephalus appendiculatus ticks, infected as nymphs by feeding them on an african buffalo harbouring theileria lawrencei, were applied to the ears of rabbits. equal numbers of the feeding ticks were removed daily from rabbits and either dissected and processed so that parasites in their salivary glands could be examined morphologically and classified, or ground in eagle's minimal essential medium, to harvest parasites from the ticks in the resultant supernatant fluid. the infectivity of ... | 1975 | 809739 |
| studies on theileriidae (sporozoa) in tanzania. iii. experiments on the transmission of theileria mutans by rhipicephalus appendiculatus and amblyomma variegatum (acarina, ixodidae). | the parasite considered to be theileria mutans in east africa could not be transmitted transstadially by rhipicephalus appendiculatus (seven attempts); it was transmitted by amblyomma variegatum in 6 out of 7 experiments. the possibility that the original south african t. mutans, transmissible by r. appendiculatus, and the parasite called t. mutans in east africa, are different species, has to be considered. | 1976 | 824772 |
| establishment of an experimental field population of theileria lawrencei-infected ticks maintained by african buffalo (syncerus caffer). | a population of rhipicephalus appendiculatus ticks infected with buffalo-derived theileria lawrencei was established in a paddock. two infected buffalo had been introduced into this paddock which contained a small population of theileria-free r. appendiculatus. at intervals, successive groups of theileria-susceptible cattle were grazed with the buffalo. transmission of t. lawrencei from buffalo to cattle was first noted 7 to 8 months after the introduction of the buffalo, this delay being accoun ... | 1977 | 915621 |
| studies on theileriidae (sporozoa) in tanzania. v. preliminary experiments on a new method for infecting ticks with theileria parva and theileria mutans. | bovine blood with a high parasitaemia of theileria mutans was injected through the cuticle into fully engorged nymphs of amblyomma variegatum which had recently detached from a rabbit. after moulting, they transmitted this parasite to a susceptible calf. rhipicephalus appendiculatus transmitted theileria parva in the same way, but results were negative with a. variegatum and t. parva. this method of infecting ticks appears promising for the isolation of theileria strains from the field, and migh ... | 1976 | 1006800 |
| the establishment of three cell lines from the tick rhipicephalus appendiculatus (acari: ixodidae) and their infection with some arboviruses. | | 1975 | 1123829 |
| the feeding behaviour of larvae, nymphs and adults of rhipicephalus appendiculatus. | the pre-feeding and feeding periods of larvae, nymphs and adults of rhipicephalus appendiculatus on rabbits (oryctolagus cuniculus) were investigated. larvae and nymphs required at least 8-9 days after hatching and moulting respectively before they could attach and start feeding, while adults required at least 6-9 days. but longer periods of starvation improved the proportion of ticks that successfully fed. after attachment, there was always an initial period of slow feeding, which was followed ... | 1976 | 1256910 |
| vaccination of cattle against rhipicephalus appendiculatus with detergent solubilized tick tissue proteins and purified 20 kda protein. | three groups of 4 cattle have been vaccinated with either detergent solubilized tick tissue proteins (smp) of male and female rhipicephalus appendiculatus, a 20 kda soluble integumental antigen, a mixture of both smp and 20 kda. two weeks after one booster injection all cattle were challenged by infestation with adult ticks. treatment had no influence on tick attachment but on cattle vaccinated by the 20 kda 32.5% fed ticks died (p < 0.001). moreover, the mean weight of ticks fed on 7 out of 12 ... | 1992 | 1290376 |
| 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 ... | 1992 | 1297956 |
| indigenous and crossbred cattle--a comparison of resistance to ticks and implications for their strategic control in zimbabwe. | a comparison of the tick resistance of indigenous mashona and crossbred afrikander x sussex oxen following natural tick infestation indicated that significantly more african blue ticks boophilus decoloratus were found on the crossbred than the indigenous cattle (p < 0.05). the two groups of cattle were exposed to babesia bigemina and theileria taurotragi as indicated by high antibody titres on the indirect fluorescent antibody test, but no antibodies could be demonstrated to anaplasma marginale ... | 1992 | 1305338 |
| saliva-activated transmission (sat) of thogoto virus: dynamics of sat factor activity in the salivary glands of rhipicephalus appendiculatus, amblyomma variegatum, and boophilus microplus ticks. | thogoto (tho) virus is transmitted from infected to uninfected ticks when co-feeding on uninfected guinea-pigs, even though the guinea-pigs do not develop a detectable viraemia. this form of non-viraemic transmission is potentiated by a factor(s) secreted by the saliva of ticks and hence has been termed saliva-activated transmission (sat). the synthesis of the sat factor by the salivary glands of three ixodid tick species was determined by placing uninfected nymphal ticks on guinea-pigs that wer ... | 1992 | 1326431 |
| histochemical changes in the midgut of two ixodid tick species boophilus microplus and rhipicephalus appendiculatus during digestion of the blood meal. | the changes in the midgut epithelia of two ixodid tick species, boophilus microplus and rhipicephalus appendiculatus, have been studied using several histochemical techniques. it was revealed that there is an accumulation of rna at the time of tick attachment to the host and prior to the arrival of the blood meal, indicating that the midgut digest cell is furnished with the machinery characteristic of a synthetic cell. there appears to be a synchrony in the appearance of granules with peroxidase ... | 1992 | 1373357 |
| immunization of guinea-pigs and cattle against adult rhipicephalus appendiculatus ticks using semipurified nymphal homogenates and adult gut homogenate. | guinea-pigs inoculated with crude homogenate of unfed nymphs of the tick rhipicephalus appendiculatus and with three semipurified fractions of the homogenate obtained by gel permeation chromatography, acquired a significant degree of immunity to infestation with adults of this tick. fraction 2 induced the highest reduction (66%) in mean weight of engorged females followed by crude homogenate and fractions 1 and 3. calves immunized with crude homogenates of unfed nymphs, fraction 2 of nymphal hom ... | 1992 | 1375584 |
| influence of exposure period and management methods on the effectiveness of chickens as predators of ticks infesting cattle. | experiments undertaken on rusinga island, kenya, indicated that rhipicephalus appendiculatus (neumann) was the predominant tick consumed on tick-infested cattle by chickens, followed by amblyomma variegatum (fabricius), boophilus decoloratus (koch) and rhipicephalus evertsi evertsi (neumann). the number of ticks consumed by chickens released with cattle in a 3 h release period was not significantly different from ticks consumed in a 4 h release period. in a free management system, chickens 1-3 m ... | 1992 | 1413461 |
| 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 ... | 1992 | 1446570 |
| tick (acari: ixodidae) attachment cement and salivary gland cells contain similar immunoreactive polypeptides. | a specific antiserum (12c) raised to a 90-kda immunogenic component of salivary glands of the tick rhipicephalus appendiculatus recognized similar 90-kda polypeptides from salivary glands of the american dog tick, dermacentor variabilis, and the lone star tick, amblyomma americanum, as well as 70-kda polypeptides in the cement of d. variabilis, a. americanum, and r. sanguineus (brown dog tick). the reduction in size of the polypeptide for these ticks suggests that it is modified in some way duri ... | 1992 | 1495047 |
| transformation of theileria parva derived from african buffalo (syncerus caffer) by tick passage in cattle and its use in infection and treatment immunization. | a sporozoite stabilate (st. 199) of theileria parva was obtained by feeding nymphal rhipicephalus appendiculatus on an african buffalo (syncerus caffer) and was used to immunize cattle by the infection and treatment method. nymphal ticks were applied to one of the steers 90 days later and it was shown that the resultant adult tick had become infected. using tick/cattle passage, two passage lines of t. parva were established. by the fifth tick/cattle passage, the parasite stocks had changed their ... | 1992 | 1496792 |
| studies on naturally acquired immunity to african ticks. ii. observations on cattle exposed to rhipicephalus appendiculatus under varying periods of repeated infestations. | groups of friesian cattle were infested repeatedly with rhipicephalus appendiculatus at weekly intervals (eight infestations) and at intervals of 3 weeks (seven infestations) and 6 weeks (seven infestations). the engorgement weight of adults, nymphs and larvae decreased significantly initially, from the second infestation, but rose significantly at later infestations. this rise was more dramatic with larval instars than with any other. a new method for quantifying the resistance status of animal ... | 1992 | 1502791 |
| augmentation of host's naturally acquired immunity by solubilized membrane-bound midgut proteins of the tick rhipicephalus appendiculatus. | immune resistance of rabbits to the hard tick rhipicephalus appendiculatus induced by combined tick infestations and immunization with solubilized midgut membrane proteins were compared with resistance due to 1-3 infestations or immunization alone. results demonstrate that the level of exposure of rabbits to ticks used in the study does not significantly affect the immune expression resulting from immunization and that the latter augments the resistance due to infestation. | 1992 | 1597790 |
| laboratory and field observations on anti-tick properties of the plant gynandropsis gynandra (l.) brig. | a shrubby plant, abundant in east kenya, gynandropsis gynandra (l.) brig., was shown to exhibit repellent and acaricidal properties to larvae, nymphs and adult rhipicephalus appendiculatus and amblyomma variegatum ticks. all stages of ticks avoided the leaves of the plant and a high percentage of the ticks which were continuously exposed to its leaves died; surviving ticks were weak and inactive but regained activity when exposed to fresh air. the effectiveness of the plant's leaves as a repelle ... | 1992 | 1615623 |
| the role of rhipicephalus appendiculatus and r. evertsi evertsi males in inducing resistance in laboratory animals: preliminary studies. | guinea-pigs infested with male ticks of the species rhipicephalus appendiculatus, and rabbits infested with r. evertsi evertsi, acquired immunity to conspecific female ticks. the hosts were first infested with male ticks and thereafter were challenged with males and females of the same species. the mean weight of the engorged females of r. appendiculatus fed on guinea pigs previously infested with male ticks was 509.0 (+/- 41.4) mg compared with that of females fed on control guinea pigs (651.2 ... | 1991 | 1720084 |
| histochemical localisation of acid phosphatase and non-specific esterase in the midguts of two species of tick, boophilus microplus and rhipicephalus appendiculatus, as determined by light microscopy. | serial sections of glycol methacrylate-embedded and frozen midguts of boophilus microplus and rhipicephalus appendiculatus were studied histochemically by light microscopy. the use of the naphthol as-tr phosphate technique combined with glycol methacrylate embedding enabled the precise localisation of lysosomal enzyme activity, despite the ubiquity of haematin granules in tick midgut epithelia. the presence of acid phosphatase and non-specific esterase activity in the same cells was observed in ... | 1991 | 1724321 |
| influence of identification ear tags on the numbers of adult rhipicephalus appendiculatus (acari: ixodidae) on the ears of cattle. | the influence of ear tags on the number of adult rhipicephalus appendiculatus was investigated. tagged ears carried significantly more ticks than untagged ears, but differences decreased with time. ticks were seen crowding under and close to the back of the tag, on the outside of the ear. | 1991 | 1748031 |
| predation of free-living engorged female rhipicephalus appendiculatus. | in experiments done over a period of 1 1/2 years using engorged female rhipicephalus appendiculatus tethered in a grass plot, 42% predation was observed in long grass (40-60 cm), and 36% in short grass (6-10 cm). deaths due to environmental factors were 4.8% and 6.8% in long and short grass, respectively. six groups of animals were confirmed to be predators of the ticks, namely: ants, spiders, rodents, birds, lizards and shrews. the implications of these results in making tick population models, ... | 1991 | 1773676 |
| parasites of domestic and wild animals in south africa. xxix. ixodid ticks on hares in the cape province and on hares and red rock rabbits in the orange free state. | one hundred and seventeen scrub hares, lepus saxatilis, were examined for ixodid ticks in various regions of the cape province. they were infested with 18 tick species and the seasonal abundances of the immature stages of amblyomma hebraeum, amblyomma marmoreum, hyalomma marginatum rufipes, rhipicephalus appendiculatus and rhipicephalus glabroscutatum and all stages of rhipicephalus oculatus and the adults of a rhipicephalus sp. (near r. oculatus) were determined. seventy-two scrub hares on 3 fa ... | 1991 | 1780126 |
| dna probes detect theileria parva in the salivary glands of rhipicephalus appendiculatus ticks. | the ability of theileria parva-specific dna probes to detect t. parva sporoblasts and sporozoites in samples prepared from the salivary glands of infected rhipicephalus appendiculatus ticks was evaluated. the two dna probes used, pgtpm-23 and igtpm-58, were selected from a genomic library of t. parva (muguga) piroplasm dna. in all, 25-200 adult ticks infected with each of 6 different t. parva stocks were tested. one salivary gland from each tick was processed for dna hybridization, whereas the o ... | 1991 | 1792229 |
| re-assessment of tick control after immunization against east coast fever in the eastern province of zambia. | east coast fever, caused by the protozoon theileria parva and transmitted by the ixodid tick rhipicephalus appendiculatus is one of the most important cattle diseases in east and central africa, responsible for considerable direct losses and necessitating expensive control measures. traditionally, the disease was controlled by means of intensive tick control. the belgian animal disease control project was requested to study the disease epizootiology and vector ecology in order to formulate and i ... | 1991 | 1793284 |
| exposure of ankole and crossbred cattle to theileriosis in rwanda. | susceptible ankole (sanga: bos indicus/bos taurus) and crossbred ankole x jersey (b. taurus) and ankole x sahiwal (b. indicus) cattle derived from a farm in rwanda with no recent history of theileriosis, were infected with theileria parva stocks from rwanda either by feeding infected rhipicephalus appendiculatus ticks on the ears, inoculation of tick derived stabilate or natural exposure to tick challenge. the ankole cattle originated from local stock born and bred in east coast fever (ecf) ende ... | 1991 | 1796523 |
| retrospective observations on the transmission of east coast fever in zimbabwe. | records of 283 outbreaks of east coast fever in zimbabwe in the period 1914 to 1946 reveal that transmission of infection occurred throughout the year with peaks in january to march and may to july. the high level of transmission in january to march coincides with the known seasonal occurrence of adult rhipicephalus appendiculatus. it is suggested that transmission at other times of the year may have been effected by a population of r. appendiculatus which did not exhibit a strictly seasonal lif ... | 1991 | 1858166 |
| predation on livestock ticks by chickens. | chickens were shown to be natural predators of ticks. rhipicephalus appendiculatus were recovered in large numbers from the crops and gizzards of chickens which had scavenged for 30 min-1 h among tick-infested cattle. other ticks recovered were amblyomma variegatum and boophilus decoloratus. the numbers of ticks recovered ranged from 3 to 331, with an average of 81 per chicken. cattle facilitated the predation of ticks by certain behavioural actions. chickens also picked up both engorged and une ... | 1991 | 1858289 |
| histopathology of attachment sites of amblyomma variegatum and rhipicephalus appendiculatus on zebu cattle of varying resistance to ticks. | mature, unimproved east african zebu cattle (bos indicus) naturally exposed to ticks from birth were ranked for resistance to ticks by repeated whole-body counts of infesting ticks. four cattle of high resistance, four of low resistance and two of intermediate resistance were artificially infested with nymphs of amblyomma variegatum and rhipicephalus appendiculatus. two friesian cattle (bos taurus) with less exposure to ticks were similarly infested. biopsies of tick attachment sites were examin ... | 1991 | 1858290 |
| acaricidal activity of kupetaba, a ground mixture of natural products, against rhipicephalus appendiculatus. | eight substances were screened for the purpose of selecting a natural product as an acaricide for use within an integrated tick management system. one substance proved to be effective as an acaricide against all stages of rhipicephalus appendiculatus and was named 'kupetaba'. it is a ground mixture of dried tobacco leaves (family solanaceae) and a mineral called 'magadi soda' which is mined around lake magadi in the rift valley province of kenya. investigation showed that kupetaba is commonly so ... | 1991 | 1882499 |
| epidemiological observations on theileriosis following field immunisation using infection and treatment. | thirty-seven high grade cattle were immunised against corridor disease (theileria parva lawrencei infection) on a farm with a history of heavy and often lethal theilerial challenge. nineteen cattle were immunised by treating with two doses of long-acting oxytetracyclines given at 20 mg/kg on days 0 and 4 after sporozoite stabilate inoculation, while the other 18 were treated with naphthoquinone buparvaquone, given as a single dose of 2.5 mg/kg simultaneously with stabilate inoculation. all the c ... | 1991 | 1907045 |
| theileria parva: influence of vector, parasite and host relationships on the epidemiology of theileriosis in southern africa. | the protozoan parasite theileria parva, transmitted by the ixodid tick rhipicephalus appendiculatus, is the cause of east coast fever (ecf) and the related syndromes of corridor disease and january disease in cattle of eastern, central and southern africa. it is likely that buffalo (syncerus caffer) are the natural host of t. parva. in eastern and southern africa, there exists both buffalo-adapted and cattle-adapted t. parva. disease caused by buffalo-adapted parasites is called corridor disease ... | 1991 | 1907728 |
| parasites of domestic and wild animals in south africa. xxv. ixodid ticks on sheep in the north-eastern orange free state and in the eastern cape province. | the tick burdens of 115 merino sheep, slaughtered over a period of 15 consecutive months on a farm in the north-eastern orange free state, were determined. a total of 7 ixodid and 1 argasid tick species were recovered and the seasonal abundances of boophilus decoloratus, hyalomma marginatum rufipes, margaropus winthemi and rhipicephalus evertsi evertsi were determined. one hundred and forty-nine merino sheep were slaughtered over periods varying from 10 to 25 months on 3 farms in eastern provinc ... | 1991 | 1923373 |
| tick (acari: ixodidae) infestations on zebu cattle in western kenya: seasonal dynamics of four species of ticks on traditionally managed cattle. | a study was conducted on the population dynamics of four tick species infesting livestock on rusinga island. infestations of rhipicephalus appendiculatus neumann, rhipicephalus evertsi evertsi neumann, amblyomma variegatum (f.)., and boophilus decoloratus (koch) were monitored on east african shorthorn zebu cattle at monthly intervals for 2 yr. these cattle were of unimproved stock under traditional husbandry without any tick control practices. most ticks were on cattle between september and mar ... | 1991 | 1941930 |
| artificial-membrane feeding of the ixodid tick, rhipicephalus appendiculatus, to repletion. | an artificial feeding device was constructed with a baudruche membrane bearing olfactory and tactile stimuli, to induce voluntary attachment and feeding of the brown ear tick, rhipicephalus appendiculatus. preparation of the membrane and experimental conditions used are described. unfed adults of r. appendiculatus, 2-3 weeks after moulting, were confined on the membrane, which was treated with cattle ear-wash and other stimuli. they attached and commenced sucking blood within 12-48 h. fully engo ... | 1991 | 1954802 |
| cross-resistance between instars of the brown ear-tick rhipicephalus appendiculatus (acarina: ixodidae). | repeated and cross-infestation of rabbits with the larvae, nymphae and adults of rhipicephalus appendiculatus showed that significant cross-resistance occurs between larvae and nymphae, and nymphae and adults. the implications of these findings in the field situation are discussed. | 1991 | 1954804 |
| purification and characterization of an anticoagulant from the salivary glands of the ixodid tick rhipicephalus appendiculatus. | an anticoagulant isolated from salivary gland extracts of the ixodid tick rhipicephalus appendiculatus was purified by gel filtration on sephadex g-100, ion exchange on deae-cellulose, aprotinin-sepharose, and by high-pressure-liquid size-exclusion chromatography. sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the anticoagulant activity was associated with a protein of an apparent mr of 65 kda. the purified molecule had a pi in the range of 8.0-8.5 on chromatofocusing and ... | 1991 | 2026216 |
| retrospective observations on the geographical relationship between rhipicephalus appendiculatus and east coast fever in southern africa. | east coast fever appeared in southern africa in 1902, after the importation of cattle from east africa, and spread throughout the range of rhipicephalus appendiculatus until it reached the southern limit of distribution of this tick in 1916. it was progressively eradicated by quarantine, destocking, slaughter and frequent dipping in arsenic. the last case occurred in swaziland in 1960. a computer based system for matching climates and ecology (climex) revealed a direct correlation between the cl ... | 1991 | 2031290 |
| tick infestations on zebu cattle in western kenya: individual host variation. | monthly collections were made of all ticks from 25 mature east african zebu cattle and 5 yearlings for 13 mo on rusinga island, lake victoria, kenya, from september 1986 to september 1987. the most common species were rhipicephalus appendiculatus neumann and amblyomma variegatum f.; boophilus decoloratus koch and rhipicephalus evertsi evertsi neumann also were present in fewer numbers. cattle were ranked according to their degree of resistance to each of the four species and to each stage in the ... | 1991 | 2033602 |
| tick infestations on zebu cattle in western kenya: quantitative assessment of host resistance. | groups of previously tick-exposed east african zebu cattle together with tick-susceptible friesian steers as controls were artificially infested with adults, nymphs, and larvae of rhipicephalus appendiculatus neumann on two occasions. comparison of the feeding performance data from the two different breeds of cattle showed significant differences in the number and weight of engorged females and the weight of engorged nymphs. data from the first challenge were used to derive a function for discri ... | 1991 | 2033603 |
| tick infestations on zebu cattle in western kenya: host resistance to rhipicephalus appendiculatus (acari: ixodidae). | tick-susceptible friesian steers were used as bait animals to assess the availability of adult rhipicephalus appendiculatus neumann on the pasture. assuming that initial gross pickup rates of ticks by cattle were similar, the numbers of female ticks that attached and the numbers that subsequently fed to maturity on individual cattle were compared based on data obtained from bait animals. the proportion of successful attachments on high-resistance (hr) cattle (0.30) was significantly less than th ... | 1991 | 2033604 |
| species identification of rhipicephalus duttoni in relation to the rhipicephalus appendiculatus group (acarina: ixodidae). | rhipicephalus duttoni neumann is a common tick species in angola, where its distribution is sympatric with that of r. zambeziensis walker. evidence is presented supporting r. duttoni as a distinct species of the r. appendiculatus group. r. duttoni showed a species-specific glucose phosphate isomerase isoenzyme pattern. the ticks, which are difficult to distinguish morphologically, could be assigned to r. duttoni or r. zambeziensis on the basis of their isoenzyme patterns. no r. appendiculatus (n ... | 1991 | 2033607 |
| seasonal abundance of ticks associated with indigenous goats on a northern transvaal farm. | the 3 most abundant tick species on indigenous goats on a northern transvaal farm were found to be rhipicephalus evertsi evertsi, rhipicephalus appendiculatus and amblyomma hebraeum. three other tick species were present in small numbers. the economical and ecological importance of the ticks found on the goats, mainly in rural areas where chemical control of ticks is practically non-existant, is discussed. the high number of goats in the study area and the shift towards alternative methods of ti ... | 1991 | 2051439 |
| non-viraemic transmission of thogoto virus: vector efficiency of rhipicephalus appendiculatus and amblyomma variegatum. | previous studies have demonstrated that thogoto virus is transmitted from infected to uninfected ticks when co-feeding on uninfected guinea-pigs, even though the guinea-pigs do not develop a detectable viraemia. furthermore, tick to tick transmission is potentiated by factors associated with the salivary glands of ticks (saliva activated transmission). the vector efficiency of 2 ixodid tick species, rhipicephalus appendiculatus and amblyomma variegatum, for thogoto virus was assessed using this ... | 1990 | 2096521 |
| replication of crimean-congo hemorrhagic fever virus in four species of ixodid ticks (acari) infected experimentally. | the vector potentials of hyalomma dromedarii koch, h. impeltatum schulze & schlottke, h. truncatum koch, and rhipicephalus appendiculatus neumann for crimean-congo hemorrhagic fever (cchf) virus (ibar 10200) were evaluated by intracoelomic inoculation. all three hyalomma species became infected; infection rates ranged between 80 and 100% at 7-14 d after inoculation, and viral titers increased in unfed specimens almost 100 times above inoculation levels within the first week following infection. ... | 1990 | 2117664 |
| immunization of cattle against theileria parva bovis and their exposure to natural challenge. | theileria parva bovis isolates were tested for their immunizing capacity under natural field challenge on willsbridge farm in the highveld of zimbabwe. fifteen susceptible sussex yearlings were immunized with the boleni stock and 15 with a mixture of three isolates from the farm, using tick-derived sporozoite stabilates. no chemoprophylaxis was used. a dose of 0.1 ml of stabilate appeared to be safe in preliminary laboratory experiments, but the reactions were severe in the sussex cattle and one ... | 1990 | 2125158 |
| the impact of pure infestations of rhipicephalus appendiculatus and amblyomma hebraeum on the productivity of cattle and implications for tick control strategies in africa. | this paper reviews studies carried out by an fao project in zimbabwe, on the effects of the ticks rhipicephalus appendiculatus and amblyomma hebraeum on the productivity of cattle. larvae and nymphs of the two species had no detectable effect on liveweight gain (lwg). the losses in lwg caused by each adult female that completed feeding were approximately 4 g for r. appendiculatus and 10 g for a. hebraeum. losses in milk production caused by both species amounted to approximately 7 g for every fe ... | 1990 | 2126617 |
| skin test to detect resistance of cattle to rhipicephalus appendiculatus ticks. | the evaluation of a skin test to detect acquired resistance to rhipicephalus appendiculatus neumann ticks is described. an extract of salivary glands of partially fed female r. appendiculatus was prepared by dissection, sonication and filtration and used for intra-dermal injection. tests were carried out on twelve calves of known resistance to r. appendiculatus and on twelve naive calves to establish threshold values for positive reactions. four rabbits naive to ticks were skin tested repeatedly ... | 1990 | 2132998 |
| a comparative study of the infection thresholds of thogoto virus in rhipicephalus appendiculatus and amblyomma variegatum. | infection thresholds of thogoto virus in 2 ixodid tick species, rhipicephalus appendiculatus and amblyomma variegatum, were compared. thogoto virus has been isolated from naturally infected r. appendiculatus and a. variegatum in central africa, where both commonly parasitize the same hosts. no significant difference was found between the infection thresholds of thogoto virus in the 2 species. the percentage of nymphs of both species infected by feeding on viremic hamsters was directly correlated ... | 1990 | 2166447 |
| efficacy of ivermectin delivered from an intraruminal sustained-release bolus against natural infestations of five african tick species on cattle. | the efficacy of ivermectin delivered by an orally administered prototype sustained-release bolus over approximately 90 days was evaluated against natural infestations of five african tick species. twenty cattle, allocated by restricted randomization based on counts of standard boophilus decoloratus, were allocated to two groups and were either given an ivermectin bolus or designated as non-medicated controls. all cattle grazed a single pasture of native grasses for 20-40 days before treatment an ... | 1990 | 2267728 |
| the isolation and transmission of an unidentified babesia sp. to cattle by hyalomma truncatum koch 1844. | an unidentified babesia sp. which causes a mild disease in cattle was isolated in a splenectomized ox that received pooled blood from field cattle. that this organism is pleomorphic and resembles babesia occultans makes it difficult to differentiate between these organisms microscopically. initially, it was suspected that this babesia could be b. occultans. several attempts to transmit this parasite transovarially with hyalomma marginatum rufipes, the vector of b. occultans, failed. continued ef ... | 1990 | 2293131 |
| geographical information systems for studying the epidemiology of cattle diseases caused by theileria parva. | data on selected variables which influence the epidemiology of cattle diseases caused by theileria parva were assembled and entered in a computerised geographical information system. variables studied included the distributions of major hosts (cattle and buffalo), the vector ticks (rhipicephalus appendiculatus and related species) and the reported presence of east coast fever, corridor disease and january disease. in addition, the distribution of climatic suitability for r appendiculatus was ass ... | 1990 | 2327044 |
| histological reactions to bites of amblyomma variagatum and rhipicephalus appendiculatus (acari: ixodidae) fed simultaneously on naive or sensitized rabbits. | histopathological studies on attachment sites of nymphs, 48 h after attachment on three groups of rabbits, have revealed differences that were related to the rabbits' previous tick experience. feeding lesions caused by amblyomma variegatum (f.) in tick-naive rabbits were extensive and the total number of inflammatory cells was about 10 times greater than that in the feeding lesions caused by rhipicephalus appendiculatus neumann fed simultaneously on contralateral ears. rabbits that were previous ... | 1990 | 2332876 |
| resistance of brahman and simmentaler cattle to southern african ticks. | field collections of ticks from two breeds of cattle in the north western transvaal showed the common tick species to be rhipicephalus appendiculatus, amblyomma hebraeum, rhipicephalus evertsi evertsi and hyalomma marginatum rufipes. the number of these ticks was higher on simmentaler than on brahman cattle. correlation was found between the number of ticks on the cattle and their serum gamma globulin levels indicating an increase in the production of antibodies. similar correlation was also fou ... | 1990 | 2339000 |
| the effect of host resistance to tick infestation on the transmission of thogoto virus by ticks. | tick-borne virus transmission was examined using guinea-pigs and hamsters previously infested with ticks. guinea-pigs developed immunity to rhipicephalus appendiculatus after a single exposure to the ticks. nymphal and adult stages that fed on resistant guinea-pigs had increased mortality during feeding, and reduced engorged weights. egg production from female ticks fed on resistant hosts fell by at least 50%. guinea-pigs maintained high levels of immunity to tick infestation for at least 210 da ... | 1990 | 2345364 |
| rhipicephalus appendiculatus feeding on rabbits and cattle: salivary-gland responses to varying host resistance. | adult rhipicephalus appendiculatus ticks were fed as three sequential infestations on both rabbits and cattle. the feedings at first infestation on naive hosts were optimum for the ticks, whereas at third infestation the hosts were resistant, as expressed by reduced tick feeding performance. ticks from naive and resistant hosts were examined for histological differences of salivary glands. in ticks fed on resistant rabbits there was a large increase in the synthesis of glycoprotein secretory gra ... | 1990 | 2350994 |
| ecology and phenology of cattle ticks in zambia: development and survival of free-living stages. | a study on development and survival of free-living stages of three important cattle ticks in zambia, amblyomma variegatum fabricus, boophilus decoloratus koch, and rhipicephalus appendiculatus neumann, was carried out to complement studies on seasonal dynamics of parasitic stages. different instars of engorged ticks were exposed under quasi-natural conditions according to the season in which they occur naturally. generally, development rates of all stages of the three species were related to tem ... | 1990 | 2350995 |
| quantitative studies on theileria parva in the salivary glands of rhipicephalus appendiculatus adults: quantitation and prediction of infection. | | 1986 | 2422131 |
| resistance of brahman and hereford cattle to african ticks with reference to serum gamma globulin levels and blood composition. | field collections of ticks from two breeds of cattle showed that the common species of ticks were amblyomma hebraeum, rhipicephalus appendiculatus and rhipicephalus evertsi evertsi. the density of these species was higher on hereford than on brahman cattle. the results also indicated that the density of immature stages of the above-mentioned ticks is higher on hereford than on brahman cattle. a positive correlation was found between the number of ticks on the cattle and the serum gamma globulin ... | 1987 | 2456184 |
| experimental infection of six species of ixodid ticks with dugbe virus (family bunyaviridae, genus nairovirus). | the vector potential of each of 6 species of colonized north american and african ixodid ticks was assessed by intracoelomic inoculation with dugbe virus (ibar 1792, 14th passage in suckling mouse brain) and viral titers were monitored after selected incubation periods. persistence of dugbe virus for greater than or equal to 53 days in 5 species (dermacentor andersoni, d. variabilis, amblyomma americanum, rhipicephalus appendiculatus, and r. sanguineus) indicates that infection occurred. viral t ... | 1989 | 2496609 |
| theilerial parasites isolated from carrier cattle after immunization with theileria parva by the infection and treatment method. | groups of cattle were immunized with 10(-2) dilutions of sporozoite stabilates of theileria parva lawrencei derived from african buffaloes either alone or in combination with theileria parva parva derived from cattle and concomitant treatment with either long or short-acting formulations of oxytetracyline. at 90 or 120 days after infection, uninfected rhipicephalus appendiculatus nymphal ticks were applied to individual immunized cattle and the resultant adults ticks were applied to individual s ... | 1989 | 2508037 |
| comparative infection rates of theileria parva lawrencei in salivary glands of rhipicephalus appendiculatus and rhipicephalus zambeziensis. | three cattle, which had been experimentally infected with theileria parva lawrencei and maintained as carriers of the infection, were each infested simultaneously with clean nymphal rhipicephalus appendiculatus and rhipicephalus zambeziensis in ear bags on separate ears. after moulting, the ensuing adult ticks were fed on rabbits for 4 days and their salivary glands were examined for infective stages of the parasite. microscopic examination revealed significantly higher infection rates in the sa ... | 1989 | 2510107 |
| difference in vector competence of two species of sympatric ticks, amblyomma variegatum and rhipicephalus appendiculatus, for dugbe virus (nairovirus, bunyaviridae). | amblyomma variegatum was shown to be a competent vector of dugbe (dug) virus whereas rhipicephalus appendiculatus was not. when dug virus was taken up orally by a. variegatum nymphs, during capillary feeding, the virus replicated and persisted through moulting to the following adult stage. in contrast, although dug virus replicated in capillary fed r. appendiculatus nymphs, the virus did not persist trans-stadially into the adult stage. if the oral route of infection was by-passed by direct inoc ... | 1989 | 2510418 |
| vector capacity of rhipicephalus appendiculatus and amblyomma variegatum for thogoto and dhori viruses. | experimental studies were undertaken to ascertain the vector potential of rhipicephalus appendiculatus neumann and amblyomma variegatum fabricius for thogoto (tho) and dhori (dho) viruses, candidate members of the orthomyxoviridae. in the first set of experiments, ticks were infected orally by feeding on viraemic hamsters. tho virus replicated in r. appendiculatus and a. variegatum, persisted trans-stadially in both tick species, and was transmitted to susceptible hosts during feeding. in contra ... | 1989 | 2519663 |
| ecological aspects of cattle tick control in central zambia. | in ecological studies in central zambia, both climate and ecotype affected population dynamics of tick species. below average rainfall for several years caused a suppression in numbers of rhipicephalus appendiculatus neumann adults. reduction in rainfall leading to changes in grazing patterns is thought to have been responsible for an increase in numbers of amblyomma variegatum fabricius adults in a grassland habitat. there were reasonable correlations between numbers of each tick species on ind ... | 1989 | 2519677 |
| resistance and cross-resistance in guinea-pigs and rabbits to immature stages of ixodid ticks. | infestation of guinea-pigs and rabbits with larvae of any one of five species of ticks, rhipicephalus appendiculatus neumann, rhipicephalus evertsi evertsi neumann, amblyomma hebrauem koch, amblyomma variegatum fabricius and ixodes ricinus l., conferred resistance in the animals when exposed to subsequent infestations with the same tick species. resistance to infestations by other tick species was not observed. | 1989 | 2519683 |
| genetic variation in the body weight of ticks of the rhipicephalus appendiculatus/zambeziensis complex. | sixteen strains of ticks of the rhipicephalus appendiculatus/zambeziensis complex were created by cross-breeding for one to three generations. the body-weights of adult male ticks of these consanguineous lines were compared. a significant genetic variation was distinguished between the groups. three classes whose mean weights varied around, respectively, 2, 3 and 4 mg/adult male tick, were found. this variation in weight may be explained by hybridization between r. appendiculatus neumann and r. ... | 1989 | 2519692 |
| the effect of virus-immune hosts on thogoto virus infection of the tick, rhipicephalus appendiculatus. | thogoto (tho) virus infections of rhipicephalus appendiculatus ticks were examined using tick hosts immune to the virus. in the first set of experiments, ticks were infected by feeding on viraemic hamsters. inter-stadial infection of tho virus was not affected when ticks ingested a virus-immune bloodmeal but there was an effect on persistence of the virus. the incidence of intra-stadial infection was reduced by at least 40% when nymphs partially fed on viraemic hamsters and completed their blood ... | 1989 | 2558460 |
| [the efficacy of alphamethrin-impregnated ear tags against ticks]. | the efficacy of 3 kinds of alphamethrin-impregnated ear tags was tested against natural amblyomma hebraeum, boophilus decoloratus, rhipicephalus appendiculatus, and rhipicephalus evertsi evertsi infestations of cattle. one type of ear tag was also tested in combination with a tail band of similar material. ticks were counted macroscopically on their predilection sites. counts of b. decoloratus, r. appendiculatus, and r. e. evertsi on all trial animals diminished steadily during the first 7d afte ... | 1989 | 2607535 |
| immune suppression induced by the brown ear tick rhipicephalus appendiculatus neumann, 1901. | the brown ear tick rhipicephalus appendiculatus suppressed in vivo and in vitro immune responses in the rabbit. humoral responses were suppressed during infestation; however, suppression was transient and was unrelated to previous exposure of hosts to similar tick infestations. immune suppression was caused by putative lymphocytotoxic factor(s) in tick salivary secretions as evidenced by in vitro lymphocytotoxicity assays. in an identical study of rhipicephalus zambeziensis, a closely related rh ... | 1989 | 2614605 |
| hybridization model for rhipicephalus appendiculatus and r. zambeziensis by glucose-p-isomerase isoenzymes. | hybrids between rhipicephalus appendiculatus and r. zambeziensis were reared and glucose-phosphate-isomerase isoenzymes were resolved by agarose electrophoresis. by phenotyping hybrids in f1 and f2 generations autosomal transmission of 2 gpi genes was demonstrated. identification of a hybrid phenotype provides a method for identifying hybrids in field collections. | 1989 | 2626261 |
| transmission of theileria parva bovis (boleni strain) to cattle resistant to the brown ear tick rhipicephalus appendiculatus (neumann). | four crossbred bos taurus oxen resistant to rhipicephalus appendiculatus and three tick naive oxen of the same breed, which were all infested with adult r. appendiculatus infected with the boleni strain of theileria parva bovis, acquired theileria infection. all four tick resistant oxen recovered after a mild febrile reaction. two of the tick naive oxen died while the third recovered after a protracted period. it is suggested that tick resistance in cattle may be an important factor in establish ... | 1989 | 2665253 |
| repetitive detection by immunoblotting of an integumental 25-kda antigen in ixodes ricinus and a corresponding 20-kda antigen in rhipicephalus appendiculatus with sera of pluriinfested mice and rabbits. | mice were pluriinfested with nymphs and rabbits, with adult ixodes ricinus. as determined by immunoblotting, greater than 50% of sera from these animals reacted against a tick antigen with a molecular weight of 25 kda, which was detected in total extracts of partially fed i. ricinus females and in tick integumental extract. it was also found in engorged nymphs but was absent from larvae. sera of i. ricinus-infested rabbits and mice or of rabbits infested with rhipicephalus appendiculatus adults ... | 1989 | 2704727 |
| development of resistance in calves to nymphs of rhipicephalus appendiculatus (acarina:ixodidae) during test feeds. | a test of host resistance to infestation by the tick rhipicephalus appendiculatus was repeated 5 times, at weekly intervals, on 2 initially susceptible calves. one hundred nymphs (nn) were used each time. pairs of tick-susceptible rabbits served as controls. the engorged nn were weighed, then allowed to moult individually, and the sex of each was noted after emergence of the adult. during the course of the experiment there was a significant reduction in mean engorged weight (especially in the pr ... | 1989 | 2707106 |
| resistance in cattle against rhipicephalus appendiculatus with an assessment of cross-resistance to r. pulchellus (acari: ixodidae). | a comparison of the yield of engorged nymphs of rhipicephalus appendiculatus and r. pulchellus was carried out between cattle highly resistant to r. appendiculatus but susceptible to r. pulchellus, and cattle and rabbits susceptible to both species. resistant cattle yielded fewer and smaller r. appendiculatus nymphs than either susceptible cattle or rabbits. more nymphs of both tick species dropped from susceptible cattle but no differences were detected in the mean weight of engorged r. pulchel ... | 1989 | 2714122 |
| parasites of domestic and wild animals in south africa. xxiv. arthropod parasites of bushbuck and common duiker in the weza state forest, natal. | one bushbuck, tragelaphus scriptus, and 1 common duiker, sylvicapra grimmia, were shot each month from may 1983 to may 1984 in the weza state forest, natal, i.e. a total of 13 animals of each species. the bushbuck were infested with 8 ixodid tick species, 2 louse species and a louse-fly species. the common duiker harboured 7 tick species and 2 louse species. ticks of the genus ixodes were the most numerous and prevalent on both antelope species, but no pattern of seasonal abundance was evident. ... | 1989 | 2726195 |
| acquired resistance to ixodid ticks induced by tick cement antigen. | antisera from guinea pigs made resistant to infestation with an ixodid tick of east and central africa, rhipicephalus appendiculatus, were used to identify the tick antigens they recognized by immunoblotting. most of the antigens were found in tick salivary glands and in tick attachment cement. antisera from r. appendiculatus-resistant guinea pigs also recognized some salivary-gland antigens in ticks of other species (r. pulchellus, r. evertsi, amblyomma variegatum and a. gemma). antibodies agai ... | 1989 | 2758939 |
| monitoring of naturally acquired and artificially induced immunity to amblyomma variegatum and rhipicephalus appendiculatus ticks under field and laboratory conditions. | the ability of rabbits, goats and cattle to acquire immunity to the ixodid ticks amblyomma variegatum and rhipicephalus appendiculatus was studied under laboratory and field conditions. rabbits were successfully immunized with crude salivary gland extract (sge) and midgut extract (me) obtained from flat or partly fed female r. appendiculatus ticks. the lowest numbers of larvae were produced by females fed on rabbits immunized with unfed midgut extract. similar reductions in larval production cou ... | 1989 | 2766896 |
| formulation of medium for tick cell culture. | we examined the effectiveness of bovine cholesterol concentrate in reducing the high level (10-20%) of fetal bovine serum (fbs) necessary to promote tick cell growth in vitro. tick cell lines isolated from embryos of anocentor nitens (ane 58), boophilus microplus (bme 26), and rhipicephalus appendiculatus (rae 25) were used. they were incubated in l-15 (bme 26) or l-15b (ane 58 and rae 25) supplemented with 10% tryptose phosphate broth (tpb), 5% (ane 58 and bme 26) or 3% fbs, 10-90 microns/ml ch ... | 1989 | 2766897 |
| delayed-type hypersensitivity test for assessing tick-immune status of cattle in zambia. | delayed-type hypersensitivity skin reactions were used to assess the tick resistance status of tonga calves in zambia. the antigen used in the tests was a homogenate of unfed nymphal rhipicephalus appendiculatus which had been shown to give protective immunity in guinea pigs to adult female r appendiculatus. there was a significant negative correlation between the intensity of the reactions and the total number of ticks (amblyomma variegatum, r appendiculatus, hyalomma truncatum, boophilus decol ... | 1989 | 2773195 |