Publications

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
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
amblyomma variegatum and associated diseases in the caribbean: strategies for control and eradication in guadeloupe.	amblyomma variegatum, introduced into guadelopue 150 years ago, has recently spread in the lesser antilles and threatens north america. two important diseases are associated with the tick: heartwater and dermatophilosis. heartwater occurs in guadeloupe, marie-galante and antigua; acute dermatophilosis exists almost everywhere the tick is present. both are very pathogenic for upgraded or newly-infested cattle. after 15 years of a. variegatum control in guadeloupe, a balance is established between ...	1990	2284130
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
[spreading of the tick amblyomma variegatum in the west indies: how can this serious menace be explained and what should be done?].	the author presents a brief history of the introduction and extension of the african tick amblyomma variegatum in the caribbean. the tick is particularly dangerous for the livestock industry because of its role as a vector of heartwater and its association with severe dermatophilosis. it is already distributed in the lesser antilles from puerto rico to barbados and st. vincent. the chronology of its sudden unexplained expansion since the 1960s corresponds well with the multiplication of the catt ...	1990	2103050
the impact of natural infestations of ticks in zambia on the productivity of cattle and implications for tick control strategies in central africa.	studies were carried out in zambia using a farming systems approach to quantify the effects of tick control on traditionally managed sanga cattle. in the first trial to investigate the effect of tick control, significant improvements in liveweight gain (lwg) occurred only in periods of medium to high challenge with adult amblyomma variegatum. however, during the first 18 months of the study when animals were young, the acaricide used caused a suppression in weight gains. a supplementary experime ...	1990	2126618
the effect of amblyomma variegatum on liveweight gain of cattle in zambia.	the effect of the tick amblyomma variegatum fabricius on liveweight gain (lwg) on yearling cattle over 16 weeks was evaluated under quasi-natural conditions. early in the exposure period when animals may have been in a state of suppressed metabolism, the effect of tick feeding on lwg was negligible. overall, however, the difference in lwg between tick-free and tick-infested groups of cattle was 4.95 kg after 16 weeks. this difference between the groups was used to estimate a lower lwg of 48-63 g ...	1990	2132999
detection of an arbovirus in an invertebrate and a vertebrate host using the polymerase chain reaction.	the ability of the polymerase chain reaction (pcr) to diagnose an arboviral infection in an arthropod vector or a mammalian host was examined. dugbe (dug) viral rna was detected in rna extracts from infected tissue samples by reverse transcription and enzymatic amplification of the resulting cdna using taq dna polymerase, followed by characterisation of the amplified product by agarose gel electrophoresis or dot-blot hybridisation. viral rna was detected in the organs and haemolymph of infected ...	1990	1707893
[prevention of cowdriosis and cases of sheep diseases in the niayes region of senegal].	sheep originating from an heartwater-free area were immunized by the infection and treatment method, using long-acting oxytetracycline. the animals were then exposed, together with control sheep to natural infection in an enzootic area. tick counts were made to monitor the infestation and establish a correlation between infestation by certain tick species, in particular amblyomma variegatum, and the occurrence of cowdriosis. in some cases of death associated with ehrlichiosis and anaplasmosis in ...	1990	2218032
[ticks and hemoparasitic diseases in cattle in senegal. iv. the southern sudan area].	the authors report on the results of an investigation on ticks and hemoparasitoses of cattle, sheep and goats in the south sudanian area of senegal. systematic routine dipping against ticks of cattle, 40 sheep and 40 goats was set during 15 months, with a view to determine the population dynamics together with an acurate localization of the different species concerned. the following parasites were collected from these ruminants: amblyomma variegatum, boophilus geigyi, hyalomma truncatum, h. m. r ...	1990	2218038
[ticks of the ixodidae family as reservoir of arboviruses in the republic of guinea. ii. arboviruses].	from 1978 to 1985, 96,167 ixodidae family were collected, from which 79 strains of the following arboviruses were isolated, i.e. 4 bhanja strains, 9 chf-congo, 20 dugbe, 24 jos (viruses ecologically related to ticks), 10 abadina, 7 bluetongue, 1 bunyamwera, 1 chikungunya, (related to ticks for the first time), 1 kindia and 2 forecariah (new viruses). the main sources for arbovirus isolation were ticks of the amblyomma variegatum genus (78.5%) followed by ticks of the boophilus (12.6%), rhipiceph ...	1990	2263738
anteroposterior gradient during nymphal-adult moulting cycle of the tropical bont tick, amblyomma variegatum (acarina: ixodidae) : correlation between ecdysteroid titers and integument structure.	the structure of the extensible (alloscutum) and inextensible (scutum) integument of the nymph, amblyomma variegatum was examined during the whole bloodmeal and the nymphal-adult moulting cycle. integumental events were tentatively correlated with the ecdysteroid levels measured by radioimmunoassay. we observed that all the integumental events were realised along an anteroposterior gradient. during the 5 days corresponding to the bloodmeal, although the hormone concentration was low, a new endoc ...	1990	28305410
acute dermatitis caused by amblyomma variegatum larvae on chickens.	acute dermatitis caused by amblyomma variegatum larvae infestation was observed in adult local nigerian chickens. skin lesions containing numerous a. variegatum larvae were observed on gross examination. histopathology showed skin haemorrhages, larvae, necrosis and infiltration of eosinophils. it was suspected that the free range life of the birds could have predisposed them to the infestation.	1990	18679988
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
comparison of known and suspected pheromonal constituents in males of african ticks, amblyomma hebraeum koch and amblyomma variegatum (fabricius).	three low molecular weight compounds were found in hexane:diethyl ether extracts of fed males of the african ticks, amblyomma variegatum (tropical bont tick) and a. hebraeum (bont tick), namely, o-nitrophenol, methyl salicylate and 2,6-dichlorophenol. these same compounds were also fond in a rinse of fed a. variegatum males, but were absent or present in only trace amounts in a rinse of fed a. hebraeum males, o-nitrophenol and methyl salicylate were present in much higher concentrations (i.e., a ...	1991	1786745
a cloned dna probe identifies cowdria ruminantium in amblyomma variegatum ticks.	heartwater, caused by cowdria ruminantium and transmitted by ticks of the genus amblyomma, is a constraint to ruminant animal production in sub-saharan africa. this rickettsial disease could spread from endemically infected areas of sub-saharan africa and certain caribbean islands to other countries, including the united states, in which amblyomma ticks exist. to detect c. ruminantium in tick vectors and animals, we made dna probes from c. ruminantium dna isolated from endothelial cell cultures. ...	1991	1774264
[seasonal dynamics of tick infestations in cattle (ixodoidea) in cattle sold in the area of yaoundé, cameroon].	among the tick species identified in cameroon, eight were found in cattle in yaoundé: amblyomma variegatum, boophilus annulatus, b. decoloratus, haemaphysalis aciculifer, hyalomma nitidum, rhipicephalus longus, rh. lunulatus, rh. sulcatus. three species, hm. aciculifer, h. nitidum and rh. lunulatus, were identified for the first time in yaoundé. rhipicephalus and hyalomma were abundant during the rainy season. boophilus was abundant throughout the year, with a maximum concentration at the end of ...	1991	1824137
[sites of fixation of amblyomma variegatum ticks on their hosts in guadeloupe (french west indies)].	the examination of 458 domestic and wild hosts of the tick a. variegatum allowed to collect 8,581 larvae, 646 nymphs, 685 adults in 9 different animal species and to determine their preferential attachment sites. in another survey on 15 goats and 5 cattle, 12,345 larvae, 2,111 nymphs and 4,625 adults were counted on the anatomic sites. immature ticks feed preferentially on the head, neck and limbs of birds, the limbs of mongoose and the limbs and ears of dogs, goats and cattle. adults feed only ...	1991	1843828
crimean-congo haemorrhagic fever virus replication in adult hyalomma truncatum and amblyomma variegatum ticks.	the kinetics of the replication of the crimean-congo haemorrhagic fever virus (cchfv) was studied in intra-anally inoculated adult hyalomma truncatum and amblyomma variegatum ticks. the virus was re-isolated by suckling mouse inoculation and revealed by antigen capture with ground ticks and indirect immunofluorescence of haemolymph. the virus was detected in ticks in the first hours post-inoculation (p.i.) and its replication was observed from 36 h p.i. onwards. virus titre reached a maximum wit ...	1991	1803413
the occurrence of streptothricosis and its association with amblyomma variegatum ticks in st. lucia.	cattle, horses, sheep and goats in all areas of st. lucia were examined to ascertain the prevalence and distribution of streptothricosis on the island and to investigate its association with the occurrence of amblyomma variegatum ticks. although the disease was found to occur throughout st. lucia it was more prevalent and generally of a more severe form in areas where a. variegatum ticks are present. a tick control programme in the north of the island appeared to have resulted in a dramatic redu ...	1991	1789020
parasite burdens and host susceptibility of zebu and n'dama cattle in village herds in gambia.	helminth and tick burdens of n'dama cattle kept in village herds were compared with parasite burdens in zebu cattle introduced into the same herds. the animals were monitored regularly for tick and helminth burdens, and blood samples were examined for differential white cell counts. the zebu were found to have significantly higher numbers of endo- and ectoparasites. the n'dama had significantly higher levels of circulating eosinophils than the zebu during peak parasite burdens. no difference in ...	1991	1788936
acaricide susceptibility of amblyomma variegatum (acari:ixodidae) from puerto rico and guadeloupe.	base-line data on acaricide susceptibility of larvae and of larvae and nymphs of the tropical bont tick, amblyomma variegatum (fabricius), from puerto rico and guadeloupe were collected on 14 and six compounds, respectively. nymphs 7-8 weeks old from puerto rico and guadeloupe, and larvae 3-4 weeks old from guadeloupe, were exposed for 24 or 48 h to residues of acetone dilutions of technical-grade or commercial formulations of acaricides on disposable glass pipettes. effectiveness of the acarici ...	1991	1773678
studies on ticks of veterinary importance in nigeria: intrinsic factors influencing oviposition and egg-hatch of amblyomma variegatum under natural conditions.	during the peak of rains of 1983, 1984 and 1985 in the forest zone of nigeria, female amblyomma variegatum engorged to various weights were subjected to different experiments for the purpose of observing the intrinsic factors which influence oviposition and egg-hatch under natural conditions. two types of oviposition patterns were observed. new terms were introduced to quantify the relationships between the daily weight loss and daily number of eggs oviposited by a tick. these terms are "actual ...	1991	1916533
distribution and incidence of ectoparasites on small mammals in a rainforest belt of southern nigeria.	a total of 174 small mammalian hosts were trapped in ekpoma, bendel state, nigeria from october, 1986 to september, 1987 and examined for ectoparasites. 108 infested hosts had 10 species of ectoparasites comprising three species of mites (laelaps (echinolaelaps) muricola, laelaps (e.) gigantea and laelaps (e.) echidninus); two species of ticks (amblyomma variegatum and ixodes sp.); two species of fleas (xenopsylla cheopis and x. braziliensis); and on especies each of sucking lice (polyplax spinu ...	1991	1928798
predators of the tick amblyomma variegatum (acari: ixodidae) in guadeloupe, french west indies.	some vertebrate species in guadeloupe are predators of free or parasitic stages of amblyomma variegatum (fabricius). among birds, 1.9% of the 421 identified animals found in the stomachs of grackles (quiscalus lugubris), 1.6% of the 364 animals found in the stomachs of free-ranging chickens, and 0.3% of the 4642 animals found in the stomach of cattle egrets (bubulcus ibis) were a. variegatum ticks. the most efficient predator of ticks was the tropical fire ant, solenopsis geminata, which was obs ...	1991	1773677
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
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
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
dissemination, replication, and trans-stadial persistence of dugbe virus (nairovirus, bunyaviridae) in the tick vector amblyomma variegatum.	the dissemination and replication of dugbe (dug) virus and its tissue tropisms in the tick vector amblyomma variegatum were examined by immunohistochemical analysis using specific antibody, in situ hybridization with a viral-complementary riboprobe, and infectivity assays of dissected tissues. dugbe virus was localized in both unfed and feeding adults inoculated as nymphs or orally infected by capillary feeding, and in nymphs infected by capillary feeding. in non-feeding ticks, the main sites of ...	1991	1867347
comparative studies on the vector capacity of the different stages of amblyomma variegatum fabricius and hyalomma rufipes koch for congo virus, after intracoelomic inoculation.	groups of nymphs and adults of hyalomma rufipes and larvae, nymphs and adults of amblyomma variegatum were infected by intracoelomic inoculation with congo virus at concentrations of 10(3.5)ld50 (group a), 10(1.5)ld50 (group b) and 10(0.5)ld50 (group c). the infection rates for the different groups were: groups a, 92-100% for all stages of ticks, except for adult h. rufipes which had 87%; group b, 56.8, 68.1 and 50.7% for larvae, nymphs and adults of a. variegatum, respectively, and 96.3 and 84. ...	1991	1907050
[asymptomatic carrier state in creole goats and cattle after recovery from cowdria infection in guadeloupe].	creole goats and cattle in guadeloupe can be carriers of cowdriosis (heartwater: cowdria ruminantium) after recovery for a period as long as 11 months in goats and 2 months in cattle. the carrier status was demonstrated by feeding amblyomma variegatum nymphs on recovered animals and the resulting adult ticks on susceptible goats. cowdria ruminantium was not detected permanently during the carrier status.	1992	1301623
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
perception of breath components by the tropical bont tick, amblyomma variegatum fabricius (ixodidae). i. co2-excited and co2-inhibited receptors.	wall-pore olfactory sensilla located in the capsule of haller's organ on the tarsus of amblyomma variegatum ticks bear cells responding to vertebrate breath: one of these sensilla contains a co2-excited receptor and a second sensillum has a co2-inhibited receptor. each of these antagonistic co2-receptors, which display typical phasic-tonic responses, monitors a different co2-concentration range. the co2-inhibited receptor is very sensitive to small concentration changes between 0 and ca. 0.2%, b ...	1992	1331433
[attempt to attract amblyomma variegatum (acarina:ixodina) on cattle previously treated with aggregation-fixation pheromones and a pyrethrinoid acaricide].	the application of synthetic pheromonal aggregation-attachment compounds or male tick extracts on certain sites of the body of bull calves reared on infested pastures did not induce any attraction of free adults on these sites. previously attached males were more attractive than synthetic pheromones or natural extracts. very small amounts of flumethrin poured directly on testicles or on the dewalp induced a large decrease in the infestation of these sites.	1992	1298024
the role of amblyomma variegatum in the transmission of heartwater with special reference to guadeloupe.	heartwater has been diagnosed in guadeloupe, marie-galante, and antigua; it induces important losses among goats and european or cross-bred cattle when local zebu creole are highly resistant to infection. amblyomma variegatum is the vector of the disease in the caribbean. the tick strain of martinique, occurring in that island that has apparently been disease-free since 1948, has not lost its ability to experimentally transmit the disease. in guadeloupe 97% of nymphs and nearly 100% of adults fe ...	1992	1626882
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
perception of breath components by the tropical bont tick, amblyomma variegatum fabricius (ixodidae). ii. sulfide-receptors.	wall-pore sensilla in the capsule of haller's organ on foreleg tarsi of the tick, amblyomma variegatum, show multicellular responses upon stimulation with human and bovine breath. filtering breath through charcoal removes the stimulant for some of these receptors. analysis by gas chromatography coupled with olfactory sensillum electrophysiological recordings indicates that an ethanol extract of the breath components trapped on charcoal contains a major stimulant eluting at the same retention tim ...	1992	1432848
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
comparative study of tick burdens in gudali and wakwa cattle under natural infestation in the subhumid highlands of wakwa, cameroon. preliminary observations.	the relative resistance to different cattle ticks of gudali and wakwa cattle with different levels of brahman breeding, grazed on natural pastures in the subhumid tropics of wakwa, cameroon, was assessed using pasture tick infestations. the basic design consisted of 5 young bulls of each breed from different sire herds. tick populations were observed in gudali and wakwa bulls over a period of four weeks when the climate was thought to be highly favourable for the free-living stages of ticks. cou ...	1992	1339999
the local effect of hypersensitive or inflammatory reactions to nymphal amblyomma variegatum on simultaneous infections with dermatophilus congolensis.	amblyomma variegatum nymphs were applied to sites infected with dermatophilus congolensis on eight rabbits. four rabbits were previously sensitized to the feeding of nymphal a. variegatum to produce hypersensitive reactions to the tick feeding; the remaining four rabbits had no previous exposure to nymphal a. variegatum and produced inflammatory reactions to the tick feeding. the resulting dermatophilosis infections were assessed for three weeks and there was a correlation between the position o ...	1993	7628235
the systemic effect of adult and immature amblyomma variegatum ticks on the pathogenesis of dermatophilosis.	the systemic effect of adult and nymphal amblyomma variegatum on the pathogenesis of experimental infections of dermatophilus congolensis was investigated. three groups of four sheep were used with all 12 sheep being infected with identical titrated doses of d. congolensis one group of sheep was simultaneously infested with adult a. variegatum the second with nymphal a. variegatum and the third group were the controls, with no exposure to ticks. assessment of the resulting infections indicate th ...	1993	8134648
seroconversion to cowdria ruminantium of malawi zebu calves, reared under different tick control strategies.	the seroconversion by indirect elisa to cowdria ruminantium over the first year of life of sixty-six malawi zebu calves born into groups which were dipped 17 times per year was compared to seroconversion of 32 calves born into non-dipped groups. amblyomma variegatum tick counts and clinical disease in each group of cattle were monitored throughout the study period. no cases of heartwater were seen in either group of calves over the first 22 months of life. only one case of heartwater was observe ...	1993	8134628
the effect of tick control on the prevalence of dermatophilosis on indigenous cattle in ghana.	the effectiveness of three tick control regimes on the occurrence of amblyomma variegatum and dermatophilosis on cattle on the coastal plains of ghana were compared. animals at one kraal were sprayed with amitraz at predilection feeding sites of ticks every second week using a high concentration minimum volume technique. animals at two other kraals were treated with a deltamethrin based pour-on acaricide; at one kraal it was applied once every month while at the other kraal it was used at strate ...	1993	8134649
cowdriosis in senegal: some epidemiological aspects.	the results of a study on the abundance of amblyomma variegatum in different ecological zones and of cowdria ruminantium infection rates in nymphal and adult ticks of the north guinean zones are given. joint research is also conducted on the evaluation of seroprevalence. in this study, it appears that the vector is most important in the north guinean zone, followed by the south sudan and the coastal niayes zones. elsewhere, the tick populations are not significant or absent. the infection rate i ...	1993	8134635
cellular responses in experimental chronic and acute dermatophilosis infections of sheep.	the cellular infiltrate into the dermis in dermatophilosis lesions is composed of a range of cell types. the aim of this study was to establish if the composition of the cellular infiltrate in chronic lesions was different from that in healing lesions. experimental dermatophilus congolensis infections of sheep were used to study the sequential changes in cell types during the course of chronic and acute infections. infestations of adult amblyomma variegatum ticks were used to produce chronic les ...	1993	8134642
an attempt to correlate cattle breed origins and diseases associated with or transmitted by the tick amblyomma variegatum in the french west indies.	by using biological data and historical research, we have tried to explain the difference between resistance and susceptibility to the diseases transmitted (cowdriosis) or associated (dermatophilosis) with the tick amblyomma variegatum, in two cattle breeds of the french west indies: the creole crossbred cattle of guadeloupe and the brahman zebu cattle of martinique. have been studied the polymorphisms of 5 independent genetic systems (erythrocytic haemoglobin, serum albumin and transferrin, the ...	1993	8134643
an attempt to identify genetic markers of resistance or susceptibility to dermatophilosis in the zebu brahman population of martinique.	dermatophilosis is a disease associated with the tick amblyomma variegatum, and a genetic predisposition to the manifestation of symptoms has been demonstrated. indeed, the creole cattle of guadeloupe constitute a population which is highly resistant to this disease, whereas the brahman zebu cattle of martinique seem very susceptible. however, in this brahman population there is a gradient regarding the severity of symptoms depending on individuals. in several herds of these pure zebu brahman, k ...	1993	8134644
the epidemiology and control of camel dermatophilosis.	camel dermatophilosis was only recently described. it appears however that it is more widespread than originally thought. in kenya it has generally been found in the main semi-arid camel rearing areas of samburu and laikipia districts although it has not yet been found in the arid areas of turkana district. in an investigation of ticks on 200 camels, no amblyomma variegatum ticks were found although many other ticks were present. a. variegatum is suspected to transmit dermatophilosis in many dom ...	1993	8134647
pathogenicity of 17 isolates of entomophagous nematodes (steinernematidae and heterorhabditidae) for the ticks amblyomma variegatum (fabricius), boophilus microplus (canestrini) and boophilus annulatus (say).	entomopathogenous nematodes are well known biocontrol agents of insects. they live in the superficial layer of the soil, a location where ticks accomplish their molt and where they oviposit their eggs, making them, theoretically, the preys of infective larvae of nematodes. seventeen strains of entomopathogenous nematodes: eight strains of steinernema and nine strains of heterorhabditis were placed in contact with each of the free living stages of three tick species: amblyomma variegatum, boophil ...	1993	7628227
the effect of inflammatory and hypersensitive reactions, in response to the feeding of the tick amblyomma variegatum, on the progression of experimental dermatophilosis infections.	initial infestations of amblyomma variegatum larvae and nymphs, on rabbits and sheep respectively, produced inflammatory reactions in the host's skin; repeated infestations resulted in an increase in development of delayed type hypersensitive reactions. dermatophilus congolensis cocci were applied in titrated doses to hosts at sites of inflammatory or hypersensitive reactions to ticks, and to control hosts with no exposure to ticks. we assessed the resulting infections for three weeks and found ...	1993	7628231
the significance of recent highlights in heartwater research.	many of the objectives identified earlier, with regard to research on cowdriosis, have been achieved during the past decade. some contributions such as the development of cowdria specific dna probes and the attenuation of the organisms are still in the experimental stage but others, such as in vitro cultivation, are already well established practices in many laboratories. serological techniques are now more widely used since other methods and other sources of antigen became available. however, p ...	1993	8134619
variability of cattle infestation by amblyomma variegatum and its possible utilisation for tick control.	a great variability of the individual infestation by amblyomma variegatum adults was observed on naturally infested gudali zebus. some of the animals (called "attractive for a. variegatum") had a tick burden 10 to 16 times higher than that of the least parasitized cattle of the herd (called "non-attractive"). ranking of the animals based on a. variegatum infestation was correlated for successive tick counts. experiments were designed to determine if the "non-attractive" cattle remained lightly i ...	1993	8134651
acaricides for eradication of the tick amblyomma variegatum in the caribbean.	the success of an eradication campaign against the tropical bont tick in the caribbean imposes the use of active acaricide compounds, if possible with residual activity, easy to apply and requiring few or no accessible water supplies and expensive application equipment. tests of in vitro susceptibility of tick strains from puerto rico and guadeloupe as well as observations of the impact of the current tick control campaigns conducted in some caribbean islands, seem to indicate that there is no p ...	1993	8134652
eradication of a new focus of amblyomma variegatum in puerto rico.	in may 1992 an infestation with the tropical bont tick appeared in a small dairy heifer replacement herd in camuy, puerto rico, a completely new site located near puerto rico's northwest coast. this finding occurred after some three years of no infestation in either puerto rico or the u.s. virgin islands and is not suspected of being associated with any previous infestations. the methods used to eradicate this tick include spray treatment at a two-week interval of all domestic livestock, with am ...	1993	8134653
potential role of cattle egrets, bubulcus ibis (ciconiformes: ardeidae), in the dissemination of amblyomma variegatum (acari: ixodidae) in the eastern caribbean.	the potential role of cattle egrets, bubulcus ibis (l.), in the dissemination of amblyomma variegatum (f.) in the eastern caribbean was evaluated. the status of cattle egrets as hosts for a. variegatum in antigua was determined during seven survey periods between september 1988 and may 1991. the mean prevalences of infestation by larvae and nymphs were 2.3 and 0.5%, respectively. the mean intensity and relative density of infestation by larvae were 8.8 (sd = 9.80) and 0.2 (sd = 0.28), respective ...	1993	8271244
[ticks and hemoparasitoses in livestock in senegal. v. the northern guinea area].	the authors report the results of a study on ticks and hemoparasitoses among cattle, sheep and goats in the north-guinean 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 to determine more accurately the preferential sites of settlement of the following different species collected from these animals: amblyomma variegatum, boophilus geigyi, hyalomma truncatum, h. marginatum rufipes, rhipiceph ...	1993	8073170
progress towards a program for the eradication of amblyomma variegatum from the caribbean.	amblyomma variegatum (fabricius), the tropical bont tick, is now widely distributed in the caribbean. eighteen islands countries are now or were recently infested with the tick. to stop the spread of this tick to other non-infested islands and to the mainland areas of south, central and north america, a regional eradication program has been proposed and endorsed by the respective governments on each of the amblyomma variegatum infested islands, including the french government and caricom member ...	1993	8134654
epidemiological studies on dermatophilosis in the caribbean.	dermatophilosis is one of the most important diseases of domestic ruminants in the caribbean islands where the clinical disease has been shown to be associated with the presence of the tick amblyomma variegatum. seroepidemiological studies were conducted to clarify the epidemiology of the disease in the region with a particular attention paid to the role of a. variegatum. a bank of 1300 cattle sera from the lesser antilles was screened by elisa for the presence of antibodies to dermatophilus con ...	1993	8161379
[epidemiology of cowdria infection in senegal. i. study of the transmission and infection level in amblyomma variegatum (fabricius, 1794) in the niayes region].	the authors report the results of research on infection rates of amblyomma variegatum nympha and imago populations by cowdria ruminantium in the niayes region as well as on the transmission rates of a. variegatum by the various stases. the experiments were carried out on sheep from the sahelian zone where the vector tick is not endemic. the infection rate, estimated by inoculating sheep with ground ticks, gave the following prevalences: t = 13.3% for nymphae and t = 1.2% for adults. the transmis ...	1993	8190980
[epidemiology of cowdria infection in senegal. ii. results of sero-epidemiological follow-up studies].	the authors report the results of sero-epidemiological monitoring of zebu, diakoré and ndama cattle in the sahel, niayes and north guinea zones, respectively. calves aged 0-3 or 3-6 months were subjected to blood sampling every three months for a period of 20 months. in the niayes and north guinea zones, the immunofluorescence test showed that about 70% of 0-1 month old calves reacted positively to the cowdria ruminantium antigen, whereas the prevalence was 92% between 3 and 6 months. after the ...	1993	8190981
in vitro feeding of instars of the ixodid tick amblyomma variegatum on skin membranes and its application to the transmission of theileria mutans and cowdria ruminatium.	an in vitro feeding method using rabbit or cattle skin membranes, applied successfully to all stages (larvae, nymphae and adults) of the ioxodid tick, amblyomma variegatum, is described. the feeding apparatus consisted of a blood container with a membrane placed on top of a tick containment unit. a carbon dioxide atmosphere of between 5 and 10% and a temperature of 37 degrees c were used as stimulants for the attachment of the ticks. high co2 concentrations in the atmosphere improved the feeding ...	1993	8233589
antibodies to cowdria ruminantium in mozambican goats and cattle detected by immunofluorescence using endothelial cell culture antigen.	endothelial cell cultures, established from bovine umbilical cord arteries and subsequently infected with cowdria ruminantium, were used as antigen in the indirect fluorescent antibody test. bovine sera (374) and caprine sera (388) collected in 6 provinces of mozambique were tested. overall, 30.4% of goat sera had antibodies to cowdria, and 43% of sera collected from cattle. north of the river save, where the tick amblyomma variegatum is highly prevalent, overall percentages of positive sera wer ...	1993	8236490
impact of natural infestation of amblyomma variegatum on the liveweight gain of male gudali cattle in adamawa (cameroon).	the effect of natural tick infestation on the liveweight gain (lwg) of male gudali zebu cattle was studied throughout a year by comparing the performances of two herds, one of which was submitted to weekly acaricidal treatment and the other was left untreated against ticks. six species of ticks were identified on the untreated animals: amblyomma variegatum, boophilus decoloratus, rhipicephalus lunulatus, rhipicephalus turanicus, hyalomma nitidum and hyalomma marginatum rufipes. most of the losse ...	1993	8249253
kinetics of male pheromone production by amblyomma variegatum (acari: ixodidae).	males of amblyomma variegatum (f.), when attached on their host, produce a pheromonal blend composed of methyl salicylate, ortho-nitrophenol, and nonanoic acid, which acts as an aggregation-attachment pheromone. using olfactometry assays, assays on hosts, and quantification of the compounds by capillary gas chromatography, the kinetics of pheromone production has been studied. males engorged for at least 10 d elicit attachment from most of the tested females. attractiveness of males for females ...	1993	8271253
detection of cowdria ruminantium by means of a dna probe, pcs20 in infected bont ticks, amblyomma hebraeum, the major vector of heartwater in southern africa.	a dna probe, pcs20, previously described for use in detection of cowdria ruminantium infections in amblyomma variegatum (the principal vector of heartwater) hybridized with c. ruminantium dna in organs of laboratory-infected a. hebraeum adult ticks (the major southern african vector of heartwater). the probe hybridized with c. ruminantium dna in 46/49 midguts from male ticks and 26/29 from females, thus indicating infection. corresponding salivary glands were less heavily infected, but infection ...	1993	8432329
experiments on the relationship between feeding of the tick amblyomma variegatum (acari: ixodidae) and dermatophilosis skin disease in sheep.	experiments on the systemic effect of feeding adult amblyomma variegatum (f.) on dermatophilosis caused by dermatophilus congolenis in six sheep were performed by feeding ticks at sites separate from sites of experimental infection with d. congolensis. comparisons were made with d. congolensis infections on six control sheep without ticks. tick-infested sheep developed chronic dermatophilosis lesions; tick-free sheep healed rapidly. on two tick-infested and two control sheep a chronological sequ ...	1993	8433320
a comparison of field tick infestation on n'dama, zebu and n'dama x zebu crossbred cattle.	tick burdens, estimated from cumulative tick counts, were determined on n'dama, zebu and f1 n'dama x zebu crossbred cattle. n'dama showed significantly fewer ticks than the zebu and f1 cattle (p < 0.001). a previous trypanosomosis infection did not affect tick burdens on the three genotypes. amblyomma variegatum had a prevalence of 84.8% and hyalomma spp. 15.2%, with the ratio similar on all cattle breeds. trypanosomosis infection increased the serological prevalence of anaplasma marginale in ze ...	1993	8493760
identification of vertebrate volatiles stimulating olfactory receptors on tarsus i of the tick amblyomma variegatum fabricius (ixodidae). i. receptors within the haller's organ capsule.	gas chromatography-coupled electrophysiological recordings (gc-el) from olfactory sensilla within the capsule of haller's organ of the tick amblyomma variegatum indicate the presence of a number of stimulants in rabbit and bovine odours, and in steer skin wash. some of these stimulants were fully identified by gas chromatography-mass spectrometry analysis and by matching electrophysiological activity of synthetic analogues as: 1) hexanal, 2-heptenal, nonanal, furfural, benzaldehyde, and 2-hydrox ...	1994	8151519
wildlife as hosts for ticks (acari) in antigua, west indies.	a survey was conducted to determine the status of wild mammals and birds as hosts for amblyomma variegatum (f.) and other tick species in antigua. surveys of wild mammals and birds were conducted periodically from september 1988 through may 1991. wild mammals surveyed included the small indian mongoose (herpestes auropunctatus hodgson), norway rat (rattus norvegicus berkenhout), and house mouse (mus musculus l.), but only mongooses were surveyed intensively. larvae and nymphs of a. variegatum, l ...	1994	8158630
cross-reactivity between hard tick antigens.	1. the present study was carried out to determine the target cells and tissues for anti-tick immunoglobulins using an indirect immunohistochemical technique. 2. sections in triplicate prepared from unfed ticks rhipicephalus appendiculatus, r. evertsi and amblyomma variegatum were used to assess the cross-reactivity of serum from guinea pigs naturally infested with these tick species or immunized against them. 3. the sections showed slight (+) to strong ( +) labelling of several structures in the ...	1994	8081294
pheromonal composition of two species of african amblyomma ticks: similarities, differences and possible species specific components.	two species of bont ticks, amblyomma hebraeum and amblyomma variegatum, common to africa were studied to compare types and quantities of compounds known or believed to serve as components of the attraction-aggregation-attachment pheromone (aaap). a complex of attraction, aggregation and attachment stimulating pheromone components are used by these ticks to detect hosts, mates and, perhaps, minimize interspecific breeding. solvent extraction of pheromone emitting ticks followed by gas chromatogra ...	1994	7628240
factors affecting the distributions of the ticks amblyomma hebraeum and a. variegatum in zimbabwe: implications of reduced acaricide usage.	the ticks amblyomma hebraeum and a. variegatum are the main vectors of heartwater, a disease of ruminants caused by cowdria ruminantium, in the agricultural areas of zimbabwe. at present, a. hebraeum is widely distributed in the dry southern lowveld, and occurs in at least seven foci in the higher rainfall highveld. amblyomma variegatum occurs in the zambezi valley and surrounding dry lowveld areas in the northwest. the distribution of a. hebraeum has changed considerably over the past 70 years, ...	1994	7628253
experimental trypanosoma congolense infection on naturally occurring ticks in n'dama and gobra zebu cattle.	the effects of experimental trypanosoma congolense infection in gambian n'dama and gobra zebu cattle on number of naturally-occurring adult ticks attaching were studied. an indirect fluorescent antibody test was performed to detect serological prevalence of cowdria ruminantium antibody. the intravenously imposed trypanosome infection did not result in significant (p > 0.05) differences in amblyomma variegatum and hyalomma spp. infestations between control and infected n'dama cattle. control n'da ...	1994	7638002
effect of acaricide control of amblyomma variegatum ticks on bovine dermatophilosis on nevis.	a sentinel group of 8 bos taurus cattle was compared with similar cattle in a herd of 90 of which 21 were pastured with the sentinels. the sentinel group was not treated with acaricide whilst the rest of the cattle were treated weekly with the organophosphate acaricide ethion. weekly counts of adult ticks and rankings of dermatophilosis were made on the sentinel herd. the remaining cattle were observed for the presence of ticks and dermatophilosis prior to the weekly treatment with acaricide. al ...	1994	8009647
lymphocyte proliferative responses and the occurrence of dermatophilosis in cattle naturally infested with amblyomma variegatum.	the proliferative response of lymphocytes from tick-infested zebu type, n'dama and friesian cattle and acaricide-treated zebu types and friesians in concanavalin a (con a) stimulated cultures was monitored regularly for periods ranging from 11 to 27 months. the numbers of ticks on the animals and the presence of dermatophilosis were also noted. the friesian cattle carried most and the n'dama fewest amblyomma variegatum ticks. the tick-infested friesians all developed severe clinical dermatophilo ...	1994	7879382
cuticular hydrocarbon composition, phenotypic variability, and geographic relationships in allopatric populations of amblyomma variegatum (acari: ixodidae) from africa and the caribbean.	gas chromatography of cuticular hydrocarbons is used to determine the degree of genetic similarity and heterozygosity among 20 populations of amblyomma variegatum (f.) collected from africa and the caribbean. twenty-one compounds were detected in at least 90% of the specimens studied; another 57 hydrocarbons were detected in a variable number of specimens, ranging from 50 to 90% of all ticks extracted. visual inspection of chromatograms revealed prominent differences in the relative abundance of ...	1994	7932599
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 ...	1994	8009646
isolation and preliminary characterisation of a previously unidentified theileria parasite of cattle in kenya.	a theileria parasite was isolated from cattle on a ranch in kenya where it caused mild theileriosis in approximately one third of the cattle exposed to natural tick challenge. the parasite was isolated by inoculation of blood into two experimental cattle. blood from one of these cattle was used to infect two splenectomised cattle which developed high piroplasm parasitaemias and severe anaemia. a blood stabilate was prepared from one of the splenectomised cattle and produced high parasitaemias in ...	1994	7973080
[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 ...	1994	7991897
[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 ...	1994	8003897
effect of acaricide treatment of cattle on amblyomma variegatum (acari: ixodidae) infestation of mongooses (carnivora: viverridae: herpestes auropunctatus) in guadeloupe, french west indies.	the effect of acaricide treatment of cattle on the infestation of the small indian mongoose (herpestes auropunctatus hodgson) by amblyomma variegatum (f.) was determined during a field evaluation of selected acaricides in guadeloupe, french west indies. from april 1990 to april 1991, cattle at one site were treated every 14 d with pour-on formulations of deltamethrin, flumethrin, or permethrin; and cattle at a second site were treated as per a local standard treatment using a spray formulation o ...	1994	8057326
ticks and control methods.	ticks are the most important ectoparasites of livestock in tropical and sub-tropical areas, and are responsible for severe economic losses both through the direct effects of blood sucking and indirectly as vectors of pathogens and toxins. feeding by large numbers of ticks causes reduction in live weight gain and anaemia among domestic animals, while tick bites also reduce the quality of hides. however, the major losses caused by ticks are due to the ability to transmit protozoan, rickettsial and ...	1994	7711310
rearing amblyomma variegatum ticks in the laboratory: a simple technique to enhance attachment.		1994	7841497
dermal gland secretions of tropical bont tick,amblyomma variegatum (acarina: ixodidae): biological activity on predators and pathogens.	when they are mechanically disturbed, all instars of the tropical bont tickamblyomma variegatum exude droplets of a liquid on the dorsal, lateral, and ventral cuticle. these spread out and quickly evaporate. in this study, the possible role of these secretions was investigated in relation to predators and pathogens. in laboratory bioassays, it was demonstrated that the secretions from engorged larvae, nymphs, and females have an antibiotic activity against the bacteria speciesbacillus thuringien ...	1994	24242646
susceptibility to different tick genera in gambian n'dama and gobra zebu cattle exposed to naturally occurring tick infestations.	tick collection on one side of the body and whole tail was performed weekly over one year on 11 gambian n'dama (bos taurus) and 11 gobra zebu (bos indicus) cattle to assess breed susceptibility to naturally occurring ticks. enzyme-linked immunosorbant assay was also performed to assess the serological prevalence of anaplasma marginale antigen and babesia bigemina antibody. packed red cell volume was measured and liveweight gain was recorded. significantly higher numbers of amblyomma variegatum ( ...	1995	7652946
laboratory reared amblyomma hebraeum and amblyomma variegatum ticks differ in their susceptibility to infection with cowdria ruminantium.	the susceptibility of laboratory reared zimbabwean amblyomma hebraeum and a. variegatum ticks to infection with geographically distinct cowdria ruminantium strains was investigated by feeding both species simultaneously on individual sheep infected with one of the four strains (crystal springs [zimbabwe], ball 3 [south africa], gardel [guadeloupe] and nigeria [nigeria]). a. hebraeum ticks demonstrated a high susceptibility to infection with all four c. ruminantium strains. in comparison, a. vari ...	1995	7589273
comparison of characteristics of life cycle in female ticks collected on n'dama and zebu cattle.	characteristics of the life cycle of female ticks (amblyomma variegatum, hyalomma truncatum and boophilus geigyi) fed on n'dama and zebu cattle were studied in the laboratory from pre-oviposition period to larval development. percentage of a. variegatum eggs hatched and engorgement weight of h. truncatum were lower in ticks collected on n'dama than on zebu cattle. laboratory results confirmed field observations of species specific tick resistance in the n'dama breed.	1995	7502345
immunoglobulin-g binding proteins in the ixodid ticks, rhipicephalus appendiculatus, amblyomma variegatum and ixodes hexagonus.	a guinea-pig immunoglobulin-g linked agarose column was used to detect the immunoglobulin-g binding proteins (igbp) in the ixodid ticks, rhipicephalus appendiculatus, amblyomma variegatum and ixodes hexagonus. igbps were found in salivary gland extract (sge) of the unfed ticks of all 3 species. the sizes of the igbps, as determined by sds-polyacrylamide gel electrophoresis, differed between species. in r. appendiculatus 2 igbp bands were detected in haemolymph collected from unfed females and ma ...	1995	7675530
salivary glands and saliva of amblyomma variegatum ticks: comparison of immatures and adults in relation to the pathogenesis of dermatophilosis.	salivary glands from immature and adult amblyomma variegatum were compared for differences in potential components responsible for the systemic aggravation by adult ticks of the skin disease dermatophilosis. whole salivary glands from adult, nymphal and larval a. variegatum ticks were compared for structural differences by light microscopy and for protein content by gel electrophoresis. type-2 salivary gland acini from adult ticks at the second stage of feeding contained significantly greater (p ...	1995	7571338
vector situation of tick-borne diseases in the caribbean islands.	the most important ticks transmitting diseases to ruminants in the caribbean islands are: amblyomma variegatum, vector of cowdriosis and associated with acute dermatophilosis; amblyomma cajennense, potential vector of cowdriosis; boophilus microplus, vector of babesiosis and anaplasmosis. at the present time, amblyomma variegatum is widespread in the lesser antilles from barbados to puerto rico. the intensity of the tick control program varies in the different islands and the tick infestation in ...	1995	7597781
the life-cycle of amblyomma variegatum (acari: ixodidae): a literature synthesis with a view to modelling.	all available information on the life-cycle of amblyomma variegatum is collated. data for each parameter are analysed to derive mathematical descriptions, which may now be used to construct a model of the life-cycle of this tick. areas for future research are identified. these include the collection of data for most parameters around threshold conditions to clarify discrepancies reported in the literature and to better quantify the relationships described, examination of the effects of photoperi ...	1995	8847166
recent acquisitions on tick and tick-borne disease resistance in n'dama (bos taurus) and gobra zebu (bos indicus) cattle.	the use of disease resistant breeds is recognised as an economically realistic alternative to acaricide application and drug administration in tick and tick-borne disease control schemes. although resistance is mainly associated with zebu (bos indicus) breeds, studies carried out in the gambia show a higher resistance to ticks and tick-borne diseases in n'dama (bos taurus) than in gobra (b. indicus) cattle. tick resistance in n'dama breed appears to be effective against those species with long h ...	1995	8532370
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 ...	1995	8551500
propagation of the tick amblyomma variegatum in the caribbean.	the tropical bont tick, amblyomma variegatum, is an african tick species which infests livestock and wildlife. it was probably introduced in the central eastern islands of the caribbean during the 18th or 19th century, with cattle shipped from senegal. in africa and the caribbean, this tick is a vector of heartwater (a rickettsial disease of ruminants) and is associated with acute dermatophilosis (a bacterial skin disease of animals). until 1948, only guadeloupe and the neighbouring islands of m ...	1995	8593414
amblyomma variegatum (acari: ixodidae): mechanism and control of arbovirus secretion in tick saliva.	saliva is considered to be the conduit by which pathogens are transmitted from blood-sucking arthropod vectors to their vertebrate hosts, but supporting evidence for this is fragmentary. to determine if thogoto (tho) virus, a tick-borne member of the influenza virus family, is transmitted via tick saliva, and whether virus replication is a prerequisite for such transmission, two experimental conditions were compared: (1) "biological transmission" and (2) "mechanical transmission." in (1), tho vi ...	1996	8631383
comparison of resistance in three breeds of cattle against african ixodid ticks.	tick resistance in three breeds of cattle, two indigenous breeds (arssi and boran) and one boran x friesian cross-bread, were compared following natural tick infestations at abernossa ranch in ethiopia. the local arssi breed was found to have the highest tick resistance, followed by the boran breed, whereas the boran x friesian was the least resistant. over a period of 12 months, from october 1991 to september 1992, a total of 32,897 ticks composed of four genera were collected from the animals. ...	1996	8665816
acquisition of resistance to the tick amblyomma variegatum in boran cattle, bos indicus and the effects of trypanosoma congolense and babesia bigemina on host resistance.	resistance was induced in cattle to the tick amblyomma variegatum by five consecutive infestations with nymphs and adults. using the principal component analysis (pca), it was found that percentage of adults engorged, percentage of adults which died, percentage of nymphs which engorged, percentage of nymphs which moulted and percentage of nymphs which died, were the main indicators of resistance against a. variegatum. the percentages of nymphs which engorged or moulted after the third infestatio ...	1996	8686177
tropical bont tick eradication campaign in the french antilles. current status.	the amblyomma variegatum eradication campaign was officially started in april 1994 in martinique and in guadeloupe, including its dependencies of marie galante, desirade and st martin. a budget of $10.5 and $5.9 million for guadeloupe and martinique, respectively, was initially (1991) calculated and considered necessary to achieve the program. however, eec, the most important donor, estimated that 75% only of this proposal was acceptable, on which it agrees to support a maximum of 50%. the balan ...	1996	8784487
potential impact of wildlife on the tropical bont tick eradication program in the caribbean.	wildlife are hosts for a. variegatum throughout its range in africa, and have been demonstrated to serve as hosts for larvae and nymphs on several islands in the caribbean. studies conducted in the caribbean have indicated that most larvae and nymphs and all adults of the tick feed on livestock; therefore, eradication can be approached through the treatment of livestock. however, since small numbers of animals such as the mongoose are infested with larvae and nymphs, these animals may represent ...	1996	8784488