Publications

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relationship of the occurrence and function of 2,6-dichlorophenol in two species of amblyomma (acari: ixodidae). 1977886561
the microanatomy of the eye of amblyomma americanum (acari: ixodidae) and resultant implications of its structure. 1977886559
ecology of the tick amblyomma hebraeum koch in the eastern cape province of south africa. i. distribution and seasonal activity.in the eastern cape province of south africa larvae of amblyomma hebraeum koch occur in well-drained, shaded habitats, with a ground cover of grass. the life cycle is normally of 3 years duration. peak larval activity occurs in the summer of the 1st year, peak nymphal activity in the spring of the 2nd year, and peak adult activity in the summer of the 3rd year. larval activity shows no direct correlation with macroclimate. adult activity is correlated with, in the following order of signficance, ...1977886412
egg output in the weights and states of engorgement of amblyomma variegatum (fabr.) and boophilus annulatus (say): (ixodoidea: ixodidae).the relationship between egg output and the weights and states of engorgement of two species of ixodid ticks amblyomma variegtum (fabr.) and boophilus annulatus (say) was studied, using over 3,000 female ticks of different sizes. based on the average weights and numbers of eggs produced, guide indices are provided for the predictability of the oviposition potential in females of different weights. linear correlation was noted between weights of the ticks and the weights and numbers of eggs they ...1977881144
resistance to toxaphene by the bont tick, amblyomma hebraeum (koch).a series of in vitro and in vivo trials confirmed resistance by the three-host bont tick, amblyomma hebraeum (koch), to toxaphene in the cape, natal and transvaal provinces of the republic of south africa, and in swaziland and transkei. resistance was present in 80 of 97 field strains examined. lindane and ddt resistance was present in the one field strain tested. the results of comparative in vivo hand spraying and plunge dipping trials confirmed those of the larval in vitro tests, thus validat ...1977874951
on the use of the scrotum for feeding larval ixodid ticks on hosts.the efficacy of feeding larval stages of amblyomma variegatum, hyalomma rufipes and boophilus decoloratus on the ears and scrotum of sheep is compared. the effect of age of larvae on the number that engorged on the animal was also investigated. a significantly greater number of larvae fed on scrotum than on ears. the greatest number of larvae engorged when they were fed on the scrotum or ear within 1-4 days of hatching. the older the larvae, the less the number that fed. the economic advantages ...1977860573
amblyomma loculosum (ixodidae): first record from continental africa. 1977845892
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.1976824772
rocky mountain spotted fever (tick-borne typhus) in south carolina: an educational program and tick/rickettsial survey in 1973 and 1974.because the incidence of spotted fever is increasing in south carolina, campaigns were carried out in 1973 and 1974 to provide the public and medical practitioners, through pamphlets and news media, with information about spotted fever and the ticks which transmit the causative agent, rickettsia rickettsii. people were also invited to save and submit live ticks removed from vegetation, animals and humans, for examination by the hemolymph test. a total of 1,186 ticks consisting of 987 dermacentor ...1975811127
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 ...1975809568
application of fluorescent antibody technique to determine infectivity rates of amblyomma americanium (l.) (acarina: ixodidae) salivary glands and oral secretions by theileria cervi (piroplasmorida: theileriidae).salivary glands and oral secretion from individual field collected ticks, or ticks infected with theileria cervi in the laboratory, were subjected to fluorescent antibody techniques to determine the reliability of the technique in the identification of t. cervi in either the oral secretion or salivary glands. results indicated that the fluorescent antibody technique can be used with a reasonable degree of success in the identification of infected salivary glands or oral secretion. oral secretion ...1976794455
proteins and free amino acids in the salivary secretion and haemolymph of the tick amblyomma hebraeum.electrophoretic and chromatographic separations of the salivary secretion of amblyomma hebraeum showed a less complex protein pattern than that of ornithodoros savignyi. a hyaluronidase active component was isolated. the haemolymph protein pattern showed a major protein fraction with a mobility slightly faster than that of bovine serum albumin.1978754123
resistance to certain organophosphorus ixodicides in the bont tick, amblyomma hebraeum koch, in the republic of south africa and swaziland.a series of in vitro trails confirmed resistance in the three-host tick, amblyomma hebraeum koch, to the organophosphorus ixodicides, dioxathion, chlorfenvinphos, quintiofos, bromophos-ethyl and a dioxathion/chlorfenvinphos combination. the results of a routine survey showed that a resistance factor of greater than 100x was present in the offspring of ticks in six of 115 field isolates tested. these six isolates were confined to the lowveld areas of the province of natal, republic of south afric ...1978752082
effects of 60co irradiation on amblyomma hebraeum koch, 1844 (acarina: ixodidae).the effects of 60co irradiation on amblyomma hebraeum koch, 1844 were studied by mating normal females to males irradiated to attain dosages of 0, 2, 4, 6 and 8 kilorad. the males of all 5 groups were observed mating 7 days after being placed on the host. the higher the irradiation dosage received by the males, progressively longer were the feeding periods of the females mated with them and fewer completed their engorgement. furthermore, the mass of the females when engorged was lower, fewer lai ...1978750959
repeated feeding of amblyomma herbraeum (acarina: ixodidae) immatures on laboratory hosts. host effects on tick yield, engorged weight and engorgement period.rabbits and sheep are unable to acquire a resistance to larvae and nymphs of amblyomma hebraeum. after repeated infestation of hosts there is no progressive decline in either the tick yield or the engorged weight of fed ticks. seasonal fluctuations in engorged weights do occur however, with the weight declining in early to midwinter and increasing in early to midsummer. changes in hose physiology as a result of low temperature acclimatization appear to be responsible for the fluctuations. tick y ...1978722460
[transovarian passage of dugbe virus in the tick amblyomma variegatum (fabricius)]. 1978719844
the activity of insect juvenile hormone mimics in larval amblyomma hebraeum koch (acarina: metastriata: ixodidae).a total of 14 insect juvenile hormone mimics was tested for activity in amblyomma hebraeum by exposing newly engorged larvae to filter paper impregnated with hormone mimics. the most active compounds used in this assay were hs 103 (6-ethyl-3-pyridyl geranyl ether; ec50=0,0018 mg/cm2), zr 512 (ethyl 3,7,11-trimethyldodeca-2,4-dienoate; ec50=0,0022 mg/cm2), hs 2 (6-methyl-3-pyridyl geranyl ether; ec50=0,0035 mg/cm2), zr 615 (n-ethyl 3,7,11-trimethyldodeca-2,4-dieneamide; ec50=0,0035 mg/cm2), zr 77 ...1978704043
preparation of primary cultures of tick cells.primary cell cultures were prepared from preimaginal bodies from the nymphal ticks, rhipicephalus sanguineus, dermacentor andersoni, and amblyomma maculatum, and from the hemocytes of late-stage nymphal and adult ticks, ornithodoros coriaceus. the dissection methods for obtaining preimaginal bodies and hemocytes for culture are described. a culture mediu, designated rml 375, was used for both culture methods. primary cultures were established with minimal contamination. preimaginal body cultures ...1978697169
actions of some transmitters and their antagonists on salivary secretion in a tick.cholinomimetics (pilocarpine, carbachol, physostigmine, acetylcholine, acetyl-beta-methylcholine) and sympathomimetics (dopamine, epinephrine), when injected into the hemolymph, provoked salivary fluid secretion in the female ixodid tick amblyomma hebraeum koch. atropine, but not tubocurarine or toxiferine, abolished pilocarpine-induced secretion without reducing the response to dopamine. reserpine and guanethidine likewise selectively attenuated pilocarpine-induced secretion. following extirpat ...1978677342
morphology of the spermatid and spermatozoon of amblyomma hebraeum koch (acarina; ixodidae).spermatids and spermatozoa of amblyomma hebraeum were examined by scanning and transmission electron microscopy as well as by freeze-etch and freeze-fracture techniques. the external surface of the spermatid is smooth except for a rim of two parallel grooves near the anterior apex. this rim probably marks the level at which a cap detaches, permitting extrusion of the inner cord during spermatozoon maturation. both ends of the spermatid are closed, the anterior part being slightly thicker than th ...1978654427
effects of gulf coast ticks on blood composition and weights of pastured hereford steers.studies conducted in 1975 and 1976 were made of lightweight herefored steers, pastured on native grass pasture and infested with gulf coast ticks, amblyomma maculatum koch. the effects of tick infestations on the blood composition and weights of steers over an 8-week period were measured each year and compared to tick-free animals maintained similarly. by the end of the 8-week study infested animals averaged 8.21 kg less than control animals in 1975 and 12.42 kg less in 1976. of the blood parame ...1978641677
field trials with pheromone-acaricide mixtures for control of amblyomma bebraeum. 1978627671
chemoreceptor organs used in detection of pheromone(s) of the tick amblyomma hebraeum (acarina: ixodidae). 1977609070
relative susceptibility of jamaican strains of boophilus microplus, amblyomma cajennense, and anocentor nitens to various acaricides. 1977604370
studies on the ecology of the tick amblyomma hebraeum koch in the eastern cape province of south africa. ii. survival and development.quantitative data are given on the survival and rate of development of amblyomma hebraeum koch in relation to temperature and humidity, in laboratory and field conditions. by comparison with other ixodid species the developmental periods of a. hebraeum are extremely long. development is most rapid at 30 c, and the duration of the developmental periods increases exponentially with decreasing temperature. oviposition occurs successfully at 15 and 30 c, egg incubation at 20 to 30 c, and larval and ...1977577931
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 ...1979553966
genetic basis for organochlorine resistance in amblyomma variegatum and information on the susceptibility on a. lepidum to organochlorine acaricides. 1979544643
comparisons of the foveae dorsales in male and female ixodid ticks amblyomma americanum, a. maculatum, dermacentor andersoni and d. variabilis (acari: ixodidae). 1979537001
localized tick bite reaction.a woman presented with a localized tick bite reaction. the tick (amblyomma americanum, the "lone star" tick) was still attached to the erythematous, indurated skin of the upper back. after several unsuccessful attempts at removal, a punch biopsy was performed, and the resultant histologic sections incorporated both tick and involved skin. the various systemic and localized tick bite reactions are discussed, as are the diagnostic dilemmas which may arise when the organism is no longer present. pu ...1979477386
a bioassay method for the pheromone(s) of the bont tick amblyomma hebraeum koch.a bioassay was developed which enabled the detection of the pheromones of the bont tick (amblyomma hebraeum koch) within 2 hours with a reproducibility of 82 +/- 13%. dried, solvent-extracted ticks were glued onto the shaved backs of rabbits. those ticks to which pheromone extract was subsequently applied strongly attracted females of the same species. in a 2-way choice test a cork disc impregnated with pheromone extract was even more attractive to female ticks than a treated dried tick.1979460823
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 ...1979460821
prevalence of parasitism by amblyomma americanum on wild turkey poults as influenced by prescribed burning.captive-raised eastern wild turkey (meleagris gallopavo silvestris) poults were allowed to forage on either recently burned plots or on plots that had not been burned during the previous 3 years. following a two hour exposure on the study plots, external parasites were recovered from all poults. the louse (menacanthus stramineus) and the lone star tick (amblyomma americanum) were the only parasites recovered. fifty-nine poults exposed to the burned plots had a significantly (p less than 0.001) l ...1979459047
theileria mutans the infectivity for cattle of parasites derived from prefed amblyomma variegatum nymphs.a steer was infected with theileria mutans (aitong) by application of infected amblyomma variegatum nymphs. uninfected a. variegatum larvae were applied to this steer when piroplasms developed. the resultant (and infected) a. variegatum nymphs were applied to the ears of rabbits. equal numbers of ticks were removed daily from rabbits and ground in eagles minimal essential medium. the infectivity of the supernatant fluid was tested in cattle. the produced supernatant fluids were infective between ...1977414391
studies on theileriidae (sporozoa) in tanzania. vii. additional note on the transmission of theileria parva.rhipicephalus evertsi successfully transmitted fatal east coast fever (theileria parva infection) in one experiment. a second one gave negative results, as did an attempted transmission of t. parva by amblyomma variegatum.1977407682
tick-borne diseases of domestic animals in northern nigeria. ii. research summary, 1966 to 1976.during the first 10 years of its existence, the department of parasitology and entomology of the faculty of veterinary medicine, ahmadu bello university in zaria, nigeria, confirmed or described for the first time the occurrence of 25 different tick-borne parasites of domestic animals in the northern part of the country. most of these organisms occur as inapparent infections but may serve as complicating factors in any adverse host condition. the transmission of babesia bigemina by boophilus dec ...1977339447
the relationship of phosphodiesterase and cyclic amp to the process of fluid secretion in the salivary glands of the ixodid tick amblyomma americanum.phosphodiesterase (pde) activity in the salivary glands of the female. amblyomma americanum decreased as the tick progressed from a slow to a rapid phase of feeding, while the rate of fluid secretion increased when glands were stimulated with cyclic amp and theophylline. dopamine stimulated pde activity and an 'inhibitory' factor was found in glands obtained from rapidly engorging ticks which decreased pde activity. these findings are discussed as they relate to the process of fluid secretion by ...1978212286
na, k-atpase in the salivary gland of the ixodid tick amblyomma hebraeum (koch) and its relation to the process of fluid secretion.total and ouabain-sensitive atpase activities were determined in the salivary glands of ticks throughout the feeding cycle. activities were very low in unfed specimens. in the glands of feeding females, the activities rose until a maximum was reached for both atpase components at approximately 200 mg. the activities remain low in males throughout the feeding period. these findings are discussed in relation to the fluid secretory process of the salivary glands.1976133818
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 ...1979122000
on the life cycle of theileria velifera (uilenberg, 1964) in the gut and the haemolymph of the tick vector amblyomma variegatum (fabriciu, 1794).the development of theileria velifera in the gut and the haemolymph of the tick vector amblyomma variegatum is described. between days three and eight after repletion various sexual stages are present in the gut of the nymphs. zygotes were detected in the gut on day 14, while undifferentiated kinetes first appeared on day 15. in the haemolymph, differentiated kinetes were observed from day 16 after repletion onwards. zygotes and kinetes were also found after the moult, in the adult tick, for a p ...1979120627
[isolation of the yellow fever virus from an egg-cluster and the larvae of the tick amblyomma variegatum].the yellow fever virus is isolated in natura from eggs of a tick amblyomma variegatum. it is then isolated from larvae issued from the same egg-cluster and also from blood of a monkey bitten by larvae of the same origin. it is reported that the same virus has been previously obtained from adults of the same species of tick. an acarine appears for the first time as a sylvatic vector and reservoir (at least temporary) of yellow fever.1979117946
theileria mutans in nigeria.two strains of bovine theileria from northern nigeria were shown to be identical to theileria mutans in the indirect immunofluorescent antibody test. one of the strains was transmitted by the tick amblyomma variegatum; large macroschizonts, typical for t mutans, could be demonstrated in infected cattle. it is concluded from these experiments and from the literature that there is reliable evidence so far for the occurrence in nigeria of only two bovine tehileria species, t mutans and t velifera.1979117536
distribution and prevalence of spotted fever group rickettsiae in ticks from south carolina, with an epidemiological survey of persons bitten by infected ticks.live ticks removed from human hosts were tested for the presence of spotted fever group rickettsiae from 1974 through 1976. spotted fever group rickettsiae were detected in dermacentor variabilis, amblyomma americanum, amblyomma maculatum, and ixodes scapularis. persons from whom positive ticks were removed in 1974 and 1975 were questioned about ensuing illness. eleven of 51 persons from whom rickettsia-positive d. variabilis were removed reported some unexplained combination of symptoms compati ...1978103448
crimean-congo hemorrhagic fever, thogoto, dugbe, and jos viruses isolated from ixodid ticks in ethiopia.from 1974 through 1976, u.s. naval medical research unit no. 5 isolated 25 strain of tick-borne virus in infant mice from 410 pools containing over 6,000 ticks, and one strain from a bird and one strain from a rodent collected in central and southern ethiopia. of these, 17 were identified as known viruses previously found in west central and east africa. there were 8 strains of jos virus from amblyomma ticks; 7 strains of dugbe virus from a bird, a rodent and from ticks; 1 strains of crimean-con ...197898066
amblyomma americanum: area control with granules or concentrated sprays of diazinon, propoxur, and chlorpyrifos. 197657127
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