Publications

some experiments on the transmission of theileria mutans (theiler, 1906) and theileria parva (theiler, 1904) by the ticks amblyomma variegatum (fabricius, 1794) and rhipicephalus appendiculatus neumann, 1901, in uganda.		1974	4607395
the effect of immersion in water on the immature stages of the ixodid ticks-rhipicephalus appendiculatus neumann 1901 and amblyomma variegatum fabricius 1794.		1973	4787718
[amblyomma variegatum of african or antillean origin and rickettsia of the dermacentroxenus genus].		1969	4933938
[notes on the ticks of sicily, with descriptions of hyalomma detritum and amblyomma variegatum].		1971	5147924
organ distribution of infectivity and complement-fixing antigen with two nigerian arboviruses.		0	5429077
field vector studies of epizootic east coast fever. vi. the occurrence of amblyomma variegatum and a. lepidum in the east coast fever zones.		1968	5750916
eradication efforts against tropical bont tick, amblyomma variegatum, in the virgin islands.		1969	5766830
[isolation of a strain of rickettsia conori from larvae of amblyomma variegatum in guadeloupe].		1966	6013770
isolation and transmission of theileria mutans (chisamba) in zambia.	theileria mutans (chisamba) was isolated from a steer at chisamba, central province, zambia by inoculation of blood into a susceptible unsplenectomised calf. the parasite was then transmitted on three occasions by nymphs and once by adult amblyomma variegatum ticks. macroschizonts, typical for t mutans, were detected in two calves for short periods. the parasite caused varying degrees of anaemia in all experimental calves, whose sera showed high antibody titres to t mutans in the indirect fluore ...	1984	6424195
studies on ticks of veterinary importance in nigeria xvii. resistance of rabbits to infestation with amblyomma variegatum and boophilus decoloratus (acari: ixodidae).	rabbits exposed to larvae, nymphs and adults of amblyomma variegatum acquired resistance to the infestation with adults of this tick. the degree of acquired resistance was lowest in the rabbits exposed once previously to larvae and highest in those exposed twice previously to adults. rabbits also acquired resistance after primary infestation with boophilus decoloratus; their resistance became very high during the thrice-repeated feeding. new terms are introduced for the quantification of the deg ...	1984	6510837
studies on ticks of veterinary importance in nigeria. xi. observations on the biology of ticks detached from the red-flanked duiker (cephamophys rufulatus) and parasites encountered in their blood.	some aspects of the biology of amblyomma variegatum and boophilus decorolatus detached from red-flanked duikers were studied. smears were also made from the blood of the duikers and examined for the presence of parasites. anaplasma marginale was the only blood parasite found in the blood smears. compared with ticks detached from cattle, duiker ticks produced a greater number of eggs. the lengths and breadths of eggs produced by duiker ticks were greater than those of cattle ticks and unlike a. v ...	1984	6538723
seasonal pattern of tick load in bunaji cattle in the subhumid zone of nigeria.	the seasonal pattern of tick load on bunaji cattle under traditional management in northern nigeria was observed over 12 months to investigate the possibilities of strategic use of acaricide. ticks were removed 2-3 times weekly by hand from 16 animals, counted and the species determined. tick load was low in the dry season (2-5 ticks per animal per week), increased after the onset of the first scattered rains, reached a peak (40 ticks per animal per week) 1 month after the beginning of the heavy ...	1984	6541842
colonization and life cycle of amblyomma variegatum (acari: ixodidae) in the laboratory in puerto rico.		1984	6694178
studies on ticks of veterinary importance in nigeria. viii. differences observed in the biology of ticks which fed on different domestic animal hosts.	ticks of the species amblyomma variegatum (fabr.), boophilus decoloratus (koch), boophilus geigyi aeschl. et morel, and hyalomma rufipes koch were detached from cattle, sheep and horses and the influence of these various hosts on the biology of ticks was investigated. no a. variegatum was found in horses. the parameters studied were preoviposition and oviposition periods, ovipositional capacity, eclosion period, hatching patterns, egg sizes and temperature effect. although the preoviposition and ...	1984	6714846
development of ixodid ticks under natural conditions in nigeria.	the developmental periods of five tick species were recorded from egg to adult stages under natural conditions. the ticks were amblyomma variegatum, boophilus decoloratus, b. geigyi, hyalomma rufipes and h. truncatum and the natural condition was a grazing field on which "open" site and "shade" were recognised. the investigation took place between april 1980 and march 1981. the hatching patterns of larvae, attachment, engorgement, larvo-nymphal and nympho-adult moulting periods and the survival ...	1984	6729999
susceptibility of ticks to acaricides in zambia.	the susceptibility of some zambian ticks to dieldrin, dioxathion, dimethoate and chlorfenvinphos was determined on two- to three-week-old larvae of amblyomma variegatum, boophilus decoloratus, b. microplus, rhipicephalus appendiculatus, r. e. evertsi and a member of the r. pravus group. some strains of b. decoloratus and r. appendiculatus were resistant to dieldrin, dioxathion and dimethoate and some r. e. evertsi were resistant to dieldrin and dioxathion. a single strain of an r. pravus group t ...	1984	6730000
development of theileria mutans (theiler, 1906) in the gut and the haemolymph of the tick amblyomma variegatum (fabricius, 1794).	the development of theileria mutans in the gut and haemolymph of its tick vector, amblyomma variegatum, was studied by giemsa-stained smears after the nymphal tick had completed engorgement on parasitaemic calves. sexual stages occurred in the gut between five and seven days after repletion. the zygotes were observed in the gut from day 29 and the kinetes from day 30, i.e. three and four days after the nymphs moulted to adults. from day 34 kinetes were observed in the haemolymph. the development ...	1980	6771935
relationship between ticks and zebu cattle in southern uganda.	tick populations were observed on zebu (bos indicus) cattle over a period of 2 years at entebbe, uganda where the climate was thought to be highly favourable for the free-living stages of ticks. collections of all instars of ticks were made from the body surfaces of the cattle at intervals of between 1 and 5 weeks. the species recorded in order of decreasing abundance were rhipicephalus appendiculatus, amblyomma variegatum, boophilus decoloratus, rhipicephalus evertsi evertsi, rhipicephalus simu ...	1982	7101465
[experimental transmission of the yellow fever virus by the tick amblyomma variegatum (f.) (author's transl)].	experimental transmission of the yellow fever virus by the tick amblyomma variegatum (f.) (the tropical bont tick) is demonstrated for the first time. the tick transmitted the virus from one monkey to another. trans-stasial passage from nymph to adult stage was also demonstrated. the possible role of amblyomma variegatum as a vector and a potential reservoir of yellow fever is discussed.	1982	7105284
quantitative studies on the proteins, free fatty acids and glycogen contents of eggs of amblyomma variegatum (fabr) and boophilus decoloratus (koch) (ticks, ixodoidea: ixodidae).		1981	7197866
arbovirus isolations from ixodid ticks infesting livestock, kano plain, kenya.	in a study conducted on the kano plain, kenya, virus isolation attempts were made on ixodid ticks collected, over a 14-month period, from livestock held in family enclosures (bomas) before releasing the animals for daily foraging. 8735 amblyomma variegatum (fabricius) were tested, 98.6% of which were taken from cattle, yielding 36 strains of dugbe (dug), four strains of nairobi sheep disease (nsd), three strains of bhanja (bha), one strain of thogoto (tho) and five strains of virus which could n ...	1980	7210125
the ultrastructure of somatic neuromuscular junctions in the tick amblyomma variegatum (fabr.).	peripheral nerve axons synapse with somatic muscle fibres in the tropical bont tick amblyomma variegatum. each fibre is innervated by numerous terminals; some of the axons synapse more than once. the nerve terminals on coxal muscle fibres contain agranular electron lucent vesicles 50 to 58 nm in size and have the specialised synaptic membranes characteristic of chemically transmitting nerve-muscle junctions. some of the terminals on trochanteral muscle fibres additionally contain larger vesicles ...	1980	7388905
susceptibility to cholinesterase-inhibiting acaricides of organochlorine-resistant and susceptible strains of amblyomma variegatum (acari: ixodidae) and in organochlorine-susceptible strain of a. lepidum.		1980	7420364
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
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
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
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
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 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
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
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
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
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
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
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
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
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
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 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
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
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
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
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
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
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
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
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
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
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
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
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
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
resistance and cross-resistance in rabbits to adults of three species of african ticks (acari: ixodidae).	resistance to rhipicephalus appendiculatus, amblyomma variegatum and amblyomma hebraeum was investigated in the laboratory by infesting rabbits with adults of each of the three species followed by homospecific or heterospecific secondary infestations. significantly lower female engorged weights and egg mass weights were taken as evidence of protective immunity. following a single infestation with adults, rabbits developed homospecific protective immunity (resistance) to only r. appendiculatus an ...	1996	8706589
tropical bont tick eradication campaign in the french antilles. current status.	the amblyomma variegatum eradication campaign was officially started in april 1994 in martinique and in guadeloupe, including its dependencies of marie galante, desirade and st martin. a budget of $10.5 and $5.9 million for guadeloupe and martinique, respectively, was initially (1991) calculated and considered necessary to achieve the program. however, eec, the most important donor, estimated that 75% only of this proposal was acceptable, on which it agrees to support a maximum of 50%. the balan ...	1996	8784487
potential impact of wildlife on the tropical bont tick eradication program in the caribbean.	wildlife are hosts for a. variegatum throughout its range in africa, and have been demonstrated to serve as hosts for larvae and nymphs on several islands in the caribbean. studies conducted in the caribbean have indicated that most larvae and nymphs and all adults of the tick feed on livestock; therefore, eradication can be approached through the treatment of livestock. however, since small numbers of animals such as the mongoose are infested with larvae and nymphs, these animals may represent ...	1996	8784488
factors of variation of amblyomma variegatum infestation on creole cattle in guadeloupe.	the level of infestation of "creole" beef cattle of guadeloupe by the tick amblyomma variegatum was recorded during a long-term survey in an experimental farm: 61 steers and 83 cows were distributed in different lots according to sex and management. they grazed continuously either on irrigated digitaria decumbens pastures or on dry native savannahs. tick numbers as well as animal weights were registered monthly. climatic data were also recorded. different acaricide treatments were tested during ...	1996	8784527
development of a computer model of the population dynamics of amblyomma variegatum and simulations of eradication strategies for use in the caribbean.	control or eradication efforts should cover wide areas because of long-range migration potential of immature ticks attached to birds, such as cattle egrets. careful follow-up inspections are also imperative. simulation 1 shows how rapidly the population numbers may expand from small numbers, either introduced or missed. simulation 4 indicates extending the treatment cycle beyond the residual effectiveness of the acaricide to save labor or funds would be false economy. the result could be to main ...	1996	8784528
the association between amblyomma variegatum and dermatophilosis: epidemiology and immunology.	a close association was found between infestation with amblyomma variegatum and the occurrence of dermatophilosis on cattle on the coastal plains of ghana. animals belonging to breeds traditionally regarded as more susceptible to the disease also tended to carry higher tick burdens. the basis of the association between infestation with this tick and the occurrence of dermatophilosis would appear to involve tick-induced immunosuppression.	1996	8809987
amblyomma tick feeding in relation to host health.	the tick amblyomma variegatum has been shown by field and controlled laboratory experiments to have a direct causal relationship with severe clinical dermatophilosis. the tick does not transmit the pathogen in the usual sense, either biologically or mechanically. the tick suppresses the immune system of the host, for unknown reasons, and this appears to enable the existing dermatophilosis to become a severe disease. there are other factors involved with the progression of dermatophilosis to clin ...	1996	8809988
the pathogenesis of dermatophilosis.	pathogen, host and environmental factors must be considered in order to understand the pathogenesis of dermatophilosis. a frequently cited sequence of events involves physical damage to the skin, bacterial multiplication in the epidermis, repeated cycles of invasion by hyphae, infiltration by neutrophils and exudate, regeneration of epidermis and reinvasion. this paper is concerned with pathogen driven mechanisms involved in the origin and development of dermatophilus congolensis infections. pri ...	1996	8809989
control of amblyomma variegatum and dermatophilosis on local and exotic breeds of cattle in ghana.	the occurrence of dermatophilosis on cattle in the tropics is closely associated with infestation by amblyomma variegatum ticks. animals that are more susceptible to the disease also tend to carry higher tick burdens. longitudinal studies carried out on the accra plains suggest that n'dama cattle acquire an enhanced degree of resistance to these ticks following initial exposure. lesions on zebu-type ghana sanga cattle tend to be confined to the predilection feeding sites of adult a. variegatum e ...	1996	8809991
heartwater in ghana: implications for control of ticks.	heartwater, an often fatal rickettsial disease of domestic ruminants transmitted by amblyomma variegatum ticks, ranks with the a. variegatum-associated skin disease dermatophilosis as a major constraint to the upgrading of livestock productivity in ghana. an epidemiological survey, using new diagnostic tests, is being carried out to determine the incidence and distribution of heartwater and other tickborne diseases in ghanaian cattle, sheep and goats. preliminary results from a longitudinal surv ...	1996	8809994
prospects for biological control of livestock ticks, rhipicephalus appendiculatus and amblyomma variegatum, using the entomogenous fungi beauveria bassiana and metarhizium anisopliae.	both beauveria bassiana and metarhizium anisopliae induced approximately 30% mortalities in adult rhipicephalus appendiculatus feeding on rabbits while m. anisopliae induced a mortality of 37% in adult amblyomma variegatum. both fungal species induced reductions in engorgement weights, fecundity, and egg hatchability in adult a. variegatum. m. anisopliae reduced fecundity by 94% in a. variegatum. furthermore, b. bassiana reduced egg hatchability to 0%, while 11% of the infected females failed to ...	1996	8812559
an assessment of host resistance to ticks on cross-bred cattle in burundi.	groups of cattle of four different cross-breeds (ankole x friesian, ankole x brown-swiss, ankole x guernsey, ankole x sahiwal) plus a group of pure ankole cattle were immunized against tick-borne diseases: east coast fever, using a theileria parva trivalent vaccine, and anaplasmosis, babesiosis and, subsequently, heartwater. with the exception of two small subgroups of ankole and ankole x sahiwal which were treated by weekly spraying using delnav, all the groups were exposed to natural field cha ...	1996	8834737
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
the efficacy of amitraz against cattle ticks in tanzania.	the efficacy of amitraz on cattle ticks was assessed by susceptibility tests, spraying and dipping trials. tests on the susceptibility of three tick species, rhipicephalus appendiculatus, amblyomma variegatum and boophilus decoloratus to amitraz (technical grade-purity 98.6% w/w) showed all 15 tick strains tested to be highly susceptible, with lc50 ranging between 0.001% and 0.03%, and lc99, between 0.01% and 0.07%. spraying trials were carried out on calves infested with r. appendiculatus, a. v ...	1996	8856759
proceedings of a workshop on the control of amblyomma variegatum and associated diseases. accra, ghana, 4 november 1994.		1996	8966770
serological survey of heartwater relative to the distribution of the vector amblyomma variegatum and other tick species in north cameroon.	a study was carried out on the spatial and temporal distribution of amblyomma variegatum and other ticks infesting sheep and goats in northern cameroon. a serological survey of heartwater (cowdriosis) using a competitive elisa was concurrently carried out in the same flocks. a. variegatum was found to be the most predominant species accounting for 48.3% of all the ticks collected. other species identified included rhipicephalus sulcatus, r. lunulatus, r. turanicus, boophilus decoloratus, b. annu ...	1997	9066062
field sampling of the tick amblyomma variegatum (acari: ixodidae) on pastures in guadeloupe; attraction of co2 and/or tick pheromones and conditions of use.	field experiments were conducted in guadeloupe to evaluate the attraction of different chemicals on a guadeloupean strain of amblyomma variegatum. such tick sampling techniques may help to assess the size of the tick population on pastures before, during and after an attempted tick eradication campaign. co2 was absolutely necessary to activate ticks, including the larvae. in addition to activation, our data suggested that co2 itself is attractive for ticks. the reactivity of the ticks varied gre ...	1997	9080680
the impact of ixodiphagus hookeri, a tick parasitoid, on amblyomma variegatum (acari: ixodidae) in a field trial in kenya.	in an experiment to investigate the effect of the tick parasitoid, ixodiphagus hookeri, on tick numbers on cattle, 150000 parasitoids were released over a period of 1 year in a field where ten cattle infested with multiple tick species were kept. amblyomma variegatum was reduced from 44 to two ticks per animal while rhipicephalus appendiculatus increased over the time of parasitoid release. during the time of release 51% of the nymphs of a. variegatum collected from the animals were parasitized. ...	1997	9080682
contribution to the knowledge of ixodidae ticks of wild mammals of somalia.	this study was based on material collected in 1983-1984 from wild mammals of the middle scebeli. low scebeli and bay regions of somalia. a total of 292 specimens (156 males, 65 females, 70 nymphase, 1 larva) from 13 host species were examined. the following species of ixodidae were identified. amblyomma variegatum (fabricius, 1794); haemaphysalis calcarata neumann, 1902; haemaphysalis spinulosa neumann, 1906; rhipicephalus armatus pocock, 1900; rhipicephalus pravus donitz, 1910; rhipicephalus pu ...	1996	9257347
on the mechanism of water vapour sorption from unsaturated atmospheres by ticks	the nascent salivary secretion of 41 partly dehydrated and unfed adult female amblyomma variegatum, 58 months post-ecdysis, during water vapour uptake at 93.5 % relative humidity and 20 °c, had an osmolality of between 298.6 and 769.7 mosmol kg-1 (mean ± s.d. 470.3±85.8 mosmol kg-1). this range would allow water vapour uptake at relative humidities of approximately 9899 %, but it would not suffice for lower relative humidities down to 8085 %, the critical equilib ...	1997	9319391
crimean-congo hemorrhagic fever in ticks (acari: ixodidae) and ruminants: field observations of an epizootic in bandia, senegal (1989-1992).	from 1989 to 1992, a longitudinal study of the relationships between different tick species and domestic ungulates in the transmission and amplification of crimean-congo hemorrhagic fever (cchf) virus was undertaken in the bandia area in senegal where the presence of the virus had been reported previously. an epizootic occurred in 1991-1992 and 22 strains of cchf virus were isolated from hyalomma marginatum rufipes koch, amblyomma variegatum (f.), rhipicephalus guilhoni morel & vassiliades, and ...	1997	9379454