Publications

arthropod surveillance programs: basic components, strategies, and analysis.	effective entomological surveillance planning stresses a careful consideration of methodology, trapping technologies, and analysis techniques. herein, the basic principles and technological components of arthropod surveillance plans are described, as promoted in the symposium "advancements in arthropod monitoring technology, techniques, and analysis" presented at the 58th annual meeting of the entomological society of america in san diego, ca. interdisciplinary examples of arthropod monitoring f ...	0	26543242
update on tick-borne rickettsioses around the world: a geographic approach.	tick-borne rickettsioses are caused by obligate intracellular bacteria belonging to the spotted fever group of the genus rickettsia. these zoonoses are among the oldest known vector-borne diseases. however, in the past 25 years, the scope and importance of the recognized tick-associated rickettsial pathogens have increased dramatically, making this complex of diseases an ideal paradigm for the understanding of emerging and reemerging infections. several species of tick-borne rickettsiae that wer ...	0	24092850
common epidemiology of rickettsia felis infection and malaria, africa.	this study aimed to compare the epidemiology of rickettsia felis infection and malaria in france, north africa, and sub-saharan africa and to identify a common vector. blood specimens from 3,122 febrile patients and from 500 nonfebrile persons were analyzed for r. felis and plasmodium spp. we observed a significant linear trend (p<0.0001) of increasing risk for r. felis infection. the risks were lowest in france, tunisia, and algeria (1%), and highest in rural senegal (15%). co-infections with r ...	0	24188709
high prevalence of rickettsia africae variants in amblyomma variegatum ticks from domestic mammals in rural western kenya: implications for human health.	tick-borne spotted fever group (sfg) rickettsioses are emerging human diseases caused by obligate intracellular gram-negative bacteria of the genus rickettsia. despite being important causes of systemic febrile illnesses in travelers returning from sub-saharan africa, little is known about the reservoir hosts of these pathogens. we conducted surveys for rickettsiae in domestic animals and ticks in a rural setting in western kenya. of the 100 serum specimens tested from each species of domestic r ...	0	25325312
rickettsia africae in amblyomma variegatum ticks, uganda and nigeria.		0	24050756
using the dfci gene index databases for biological discovery.	the dfci gene index web pages provide access to analyses of ests and gene sequences for nearly 114 species, as well as a number of resources derived from these. each species-specific database is presented using a common format with a home page. a variety of methods exist that allow users to search each species-specific database. methods implemented currently include nucleotide or protein sequence queries using wu-blast, text-based searches using various sequence identifiers, searches by gene, ti ...	0	20205187
agricultural biosecurity.	the prevention and control of new pest and disease introductions is an agricultural challenge which is attracting growing public interest. this interest is in part driven by an impression that the threat is increasing, but there has been little analysis of the changing rates of biosecurity threat, and existing evidence is equivocal. traditional biosecurity systems for animals and plants differ substantially but are beginning to converge. bio-economic modelling of risk will be a valuable tool in ...	0	17761470
physiological diversity in insects: ecological and evolutionary contexts.		0	19212462
antibodies against rickettsia in humans and potential vector ticks from dhofar, oman.	to determine the extent of rickettsial infections prevalence of potential vector ticks in the rural population of dhofar, oman.	0	24019699
organ distribution of infectivity and complement-fixing antigen with two nigerian arboviruses.		0	5429077
molecular detection of rickettsia africae in amblyomma variegatum collected from sudan.	despite the increasing awareness of the importance of emerging vector-borne diseases, human tick-borne diseases, particularly rickettsial infections, are overlooked, especially in the countries such as sudan with limited resources to perform molecular-based surveys. this study aimed at detection and genetic characterization of rickettsia spp. in ticks collected from sudan. the samples were first screened for the presence of rickettsial agents by glta real-time pcr and subsequently characterized ...	0	25988442
in vitro effect of the ethanolic extract of tephrosia vogelii on rhipicephalus sanguineus in abomey-calavi.	ticks are vectors of several diseases, of which many are zoonosis transmissible to humans. the use of tephrosia leafs' extract as a low cost acaricide is spreading among farmers in central kenya.	0	26101758
a further case of gynandromorphism, observed on an amblyomma variegatum govurensis t. dias, 1950.		1953	13171567
ticks (ixodidae) on migrating birds in egypt, spring and fall 1962.	over a number of years studies have been carried out in egypt on the transport by migrating birds of ticks that may transmit pathogens of man and animals. in continuation of these investigations 11 036 birds migrating southwards through egypt were examined for ticks during the fall of 1962. the 881 infested birds (comprising 24 species and sub-species represented by 10 612 individuals) yielded 1442 ticks. tick-host relationships were similar to those of previous years except that in 1962 the pre ...	1964	14163959
[isolation of a strain of rickettsia conori from larvae of amblyomma variegatum in guadeloupe].		1966	6013770
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
[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
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
human skin lesions in east central state, nigeria due to the larvae of amblyomma variegatum (fabricius, 1794).		1973	16366347
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 tick amblyomma variegatum (ixodidae), apparently resistant to arsenic, in madagascar].		1975	1230882
development of theileria mutants (aitong) in the tick amblyomma variegatum compared to that of t. parva (muguga) in rhipicephalus appendiculatus.	a comparison was made between the development of theileria mutans (aitong) in adult amblyomma variegatum ticks and the development of t. parva (muguga) in adult rhipicephalus appendiculatus ticks. both batches of ticks dropped as engorged nymphs from cattle whose intraerythrocytic parasitemias were approximately 40%, and it was thus possible to make a direct comparison of the infection rates produced in their tick hosts in this experiment by the 2 species of theileria. ticks of the 2 batches wer ...	1975	809568
[isolation of thogoto virus from amblyomma and boophilus ticks in central africa].	a survey has been carried out in the cameroons and the central african republic about the role of the ticks in the ecology of arboviruses in central africa. attempts for virus isolation were made for 12,678 amblyomma variegatum, 3,276 boophilus decoloratus and 1,769 boophilus annulatus, by inoculation into suckling mice. from 968 pools which were inoculated, 20 yielded isolates which were identified to thogoto virus. considering previously published results concerning tick-borne virus isolations ...	1976	1037382
studies on theileriidae (sporozoa) in tanzania. iii. experiments on the transmission of theileria mutans by rhipicephalus appendiculatus and amblyomma variegatum (acarina, ixodidae).	the parasite considered to be theileria mutans in east africa could not be transmitted transstadially by rhipicephalus appendiculatus (seven attempts); it was transmitted by amblyomma variegatum in 6 out of 7 experiments. the possibility that the original south african t. mutans, transmissible by r. appendiculatus, and the parasite called t. mutans in east africa, are different species, has to be considered.	1976	824772
tick paralysis in a sheep caused by nymphs of amblyomma variegatum. a preliminary report.		1976	988681
studies on theileriidae (sporozoa) in tanzania. v. preliminary experiments on a new method for infecting ticks with theileria parva and theileria mutans.	bovine blood with a high parasitaemia of theileria mutans was injected through the cuticle into fully engorged nymphs of amblyomma variegatum which had recently detached from a rabbit. after moulting, they transmitted this parasite to a susceptible calf. rhipicephalus appendiculatus transmitted theileria parva in the same way, but results were negative with a. variegatum and t. parva. this method of infecting ticks appears promising for the isolation of theileria strains from the field, and migh ...	1976	1006800
studies on theileriidae (sporozoa) in tanzania. i. tick transmission of haematoxenus veliferus.	haematoxenus veliferus was experimentally transmitted in cattle on two occasions by the tick amblyomma variegatum; transmission was transstadial, from nymph to adult. theileria mutans and cowdria ruminatium were transmitted at the same time. h. veliferus infected at least 15% of red cells in a splenectomized steer and 10% in a normal steer. one experiment on transstadial transmission from larva to nymph was unsuccessful.	1976	1258136
tick-borne diseases of domestic animals in northern nigeria. ii. research summary, 1966 to 1976.	during the first 10 years of its existence, the department of parasitology and entomology of the faculty of veterinary medicine, ahmadu bello university in zaria, nigeria, confirmed or described for the first time the occurrence of 25 different tick-borne parasites of domestic animals in the northern part of the country. most of these organisms occur as inapparent infections but may serve as complicating factors in any adverse host condition. the transmission of babesia bigemina by boophilus dec ...	1977	339447
use of high-performance liquid chromatography to separate very small quantities of radio-labelled metabolites from biological tissue.	in order to study the absorption, metabolism and tissue distribution of chemicals in cattle ticks amblyomma variegatum, a method of separating and recovering metabolites in picogram quantities was required. a high-performance liquid chromatographic system has been investigated for this purpose, using tritium-labelled amitraz and some potential metabolites. separation was carried out on nucleosil 5 mum no2 bonded phase. interchangeable pre-columns were used to extend the range of compounds which ...	1977	914943
egg output in the weights and states of engorgement of amblyomma variegatum (fabr.) and boophilus annulatus (say): (ixodoidea: ixodidae).	the relationship between egg output and the weights and states of engorgement of two species of ixodid ticks amblyomma variegtum (fabr.) and boophilus annulatus (say) was studied, using over 3,000 female ticks of different sizes. based on the average weights and numbers of eggs produced, guide indices are provided for the predictability of the oviposition potential in females of different weights. linear correlation was noted between weights of the ticks and the weights and numbers of eggs they ...	1977	881144
on the use of the scrotum for feeding larval ixodid ticks on hosts.	the efficacy of feeding larval stages of amblyomma variegatum, hyalomma rufipes and boophilus decoloratus on the ears and scrotum of sheep is compared. the effect of age of larvae on the number that engorged on the animal was also investigated. a significantly greater number of larvae fed on scrotum than on ears. the greatest number of larvae engorged when they were fed on the scrotum or ear within 1-4 days of hatching. the older the larvae, the less the number that fed. the economic advantages ...	1977	860573
theileria mutans the infectivity for cattle of parasites derived from prefed amblyomma variegatum nymphs.	a steer was infected with theileria mutans (aitong) by application of infected amblyomma variegatum nymphs. uninfected a. variegatum larvae were applied to this steer when piroplasms developed. the resultant (and infected) a. variegatum nymphs were applied to the ears of rabbits. equal numbers of ticks were removed daily from rabbits and ground in eagles minimal essential medium. the infectivity of the supernatant fluid was tested in cattle. the produced supernatant fluids were infective between ...	1977	414391
studies on theileriidae (sporozoa) in tanzania. vii. additional note on the transmission of theileria parva.	rhipicephalus evertsi successfully transmitted fatal east coast fever (theileria parva infection) in one experiment. a second one gave negative results, as did an attempted transmission of t. parva by amblyomma variegatum.	1977	407682
[transovarian passage of dugbe virus in the tick amblyomma variegatum (fabricius)].		1978	719844
genetic basis for organochlorine resistance in amblyomma variegatum and information on the susceptibility on a. lepidum to organochlorine acaricides.		1979	544643
on the life cycle of theileria velifera (uilenberg, 1964) in the gut and the haemolymph of the tick vector amblyomma variegatum (fabriciu, 1794).	the development of theileria velifera in the gut and the haemolymph of the tick vector amblyomma variegatum is described. between days three and eight after repletion various sexual stages are present in the gut of the nymphs. zygotes were detected in the gut on day 14, while undifferentiated kinetes first appeared on day 15. in the haemolymph, differentiated kinetes were observed from day 16 after repletion onwards. zygotes and kinetes were also found after the moult, in the adult tick, for a p ...	1979	120627
theileria mutans in nigeria.	two strains of bovine theileria from northern nigeria were shown to be identical to theileria mutans in the indirect immunofluorescent antibody test. one of the strains was transmitted by the tick amblyomma variegatum; large macroschizonts, typical for t mutans, could be demonstrated in infected cattle. it is concluded from these experiments and from the literature that there is reliable evidence so far for the occurrence in nigeria of only two bovine tehileria species, t mutans and t velifera.	1979	117536
[isolation of the yellow fever virus from an egg-cluster and the larvae of the tick amblyomma variegatum].	the yellow fever virus is isolated in natura from eggs of a tick amblyomma variegatum. it is then isolated from larvae issued from the same egg-cluster and also from blood of a monkey bitten by larvae of the same origin. it is reported that the same virus has been previously obtained from adults of the same species of tick. an acarine appears for the first time as a sylvatic vector and reservoir (at least temporary) of yellow fever.	1979	117946
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
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
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
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
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
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
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
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
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
[ecology of tick-borne arboviruses in the central african republic].	ticks have been collected on cattle skins for seven consecutive years in bangui, berberati, bangassou and bouar. 150 strains of arboviruses have been isolated from the four following species: amblyomma variegatum: dugbe, jos, thogoto, crimean-congo hemorragic fever (cchf), yellow fever, bhanja and pétévo; boophilus annulatus: dugbe, jos and thogoto; b. decoloratus: dugbe, jos, thogoto and cchf; hyalomma nitidum: cchf. dugbe (112 isolated strains), jos (19 isolates) and thogoto (11 isolates) viru ...	1985	4028317
ticks on livestock in st. lucia.	cattle, sheep, goats and horses were examined for ticks. over 95% of holstein cross-breeds, 28% of sheep (local mixed breeds) and 18% of goats (local mixed breeds) examined from 18 august to 4 september 1983 were infested with the southern cattle tick, boophilus microplus canestrini. about 90 and 17% of the horses examined were infested with the tropical horse tick, anocentor nitens neumann, and the tropical bont tick, amblyomma variegatum fabricius, respectively. the tropical bont tick was foun ...	1985	4090245
prevalence of ectoparasites of small ruminants in nsukka, nigeria.	over a period of one year (january 1983 to december 1983), an investigation was mounted to determine common ectoparasitic infestation of small ruminants in selected farms in nsukka, nigeria. the species identified in goats included ctenocephalides canis, boophilius decolouratus and amblyomma variegatum lides while those recovered from parasitized sheep were ctenocephalides canis and damalinia ovis. out of a total of 148 sheep and goats examined for ectoparasites, 68 (45.95%) were infested. a fur ...	1985	3836218
observations on the efficacy of ivermectin in the control of cattle ticks in zambia.	the efficacy of multiple subcutaneous injections (200 micrograms/kg) of ivermectin in the control of naturally occurring tick infestations on traditionally managed tonga-iia (sanga type) calves and yearlings was assessed in two field trials. in the first trial boophilus decoloratus infestations were decreased following treatments at monthly intervals. in the second trial, with weekly and two weekly treatment intervals, infestations of rhipicephalus appendiculatus were controlled less effectively ...	1985	3841240
[preliminary note on the sensitivity of amblyomma variegatum and boophilus decoloratus (acarida, ixodidae) to organophosphate acaricides in the people's republic of the congo].		1985	3841963
studies on ticks of veterinary importance in nigeria. xii. oviposition and eclosion in five species of ixodid ticks in contrasting habitats.	the preoviposition and oviposition periods, the eclosion periods and numbers of eggs laid by adult ticks of five species, namely amblyomma variegatum, boophilus decoloratus, b. geigyi, hyalomma rufipes and h. truncatum, maintained in a natural habitat were compared with those maintained in semi-natural and artificial habitats. within the natural habitats, "open" and "shady" sites were distinguished. maximum oviposition occurred during the peak of the rains in engorged a. variegatum and b. decolo ...	1985	3870956
[isolation of a new orbivirus kindia (palyam group) from ticks amblyomma variegatum in the republic of guinea].	a new arbovirus named "kindia" has been isolated from ticks amblyomma variegatum in guinea (west africa), district kindia. this virus is classified into palyam group of orbiviruses, due to its physico-chemical, biological and antigenic properties.	1986	3731365
field tests of the response of female amblyomma variegatum (acari:ixodidae) to the synthetic aggregation-attachment pheromone and its components.	fifty percent of an amblyomma variegatum female population were able to find upwind-positioned targets containing the synthetic aggregation-attachment pheromone of this species or the pheromone component o-nitrophenol alone. the ticks were not attracted to the other components of the pheromone: methyl-salicylate and pelargonic acid. the mean time required for the ticks to reach a target at 1 m from the starting point was 3 min and 20 s.	1986	3451866
theileria orientalis occurs in central africa.	an outbreak of bovine theileriosis in burundi was investigated and the occurrence of theileria orientalis in central africa was confirmed for the first time. its identity was established on morphological and serological grounds. the parasite was associated with clinical signs and further complicates the disease picture of bovine theileriosis in africa. amblyomma variegatum is suspected as being the local vector.	1986	3517994
ecology and phenology of ticks in zambia: seasonal dynamics on cattle.	a study of the seasonality and infestation rates of ticks was carried out in 11 cattle herds in different ecological habitats in zambia between 1980 and 1982. wherever possible supplementary data were obtained from opportunistic collections from cattle and other hosts. analysis of over 1000 tick collections from cattle indicated that infestation rates of the most important species, amblyomma variegatum and rhipicephalus appendiculatus vary in different ecological habitats: (i) in western provinc ...	1986	3451861
amblyomma variegatum and acute bovine dermatophilosus.		1986	15462727
amblyomma variegatum (acari: ixodidae): population dynamics and hosts used during an eradication program in puerto rico.		1987	3820244
[oviposition and longevity of amblyomma variegatum fabricius, 1794 (ixodoidea : ixodidae) ticks in the people's republic of the congo].		1987	3453516
[trial of flumethrine for amblyomma variegatum tick control on a cattle ranch in guadeloupe].		1987	3453502
tick infestations on livestock in the yemen arab republic and their potential as vectors of livestock diseases.	a survey of ticks on cattle, camels, sheep, goats and donkeys in four different geographical locations of the yemen arab republic (yar) was carried out to provide more information on the possible risk of tick-borne diseases to imported exotic cattle included in the yar's plans for livestock development. the most abundant ticks were hyalomma spp. particularly on camels. ticks found on cattle included hyalomma spp., amblyomma variegatum, boophilus annulatus and rhipicephalus spp. in general with t ...	1987	3603710
the ecology of the african vectors of heartwater, with particular reference to amblyomma hebraeum and amblyomma variegatum.	the hosts, sites of attachment, life cycle, habitat requirements and seasonal abundance of amblyomma astrion, amblyomma cohaerens, amblyomma gemma, amblyomma hebraeum, amblyomma lepidum, amblyomma marmoreum, amblyomma pomposum, amblyomma sparsum, amblyomma tholloni and amblyomma variegatum, the 10 potential vectors of heartwater in africa, are listed. factors influencing the distribution and abundance of the ticks as well as interactions with other species and the role of predators and pathogens ...	1987	3329326
danger of introducing heartwater onto the american mainland: potential role of indigenous and exotic amblyomma ticks.	the existence of heartwater on 3 islands of the central lesser antilles and the presence of an efficient vector originating from africa, amblyomma variegatum, on most of the islands of this region constitute a serious threat for livestock on the american mainland. the disease can be introduced there either by infected animals or infected ticks. the most likely way is probably the transportation of domestic animals which are heavily infested by ticks. due to the low rate of infection of ticks in ...	1987	3329328
chemical control of the heartwater vectors.	this paper reviews available literature on the efficacy of acaricides against amblyomma hebraeum and other tick species, and presents information on tests done with registered chemicals in the laboratory. little published information is available on the efficacy of chemicals specifically against a. hebraeum. a host of formulations are registered for use as acaricides on cattle, sheep, and goats in south africa and thus, by implication, against this species. resistance has only been described to ...	1987	3329335
the reservoir status of goats recovered from heartwater.	experiments were conducted with creole goats and amblyomma variegatum ticks in guadeloupe to investigate whether it is possible to transmit cowdria ruminantium to susceptible hosts with nymphs fed in the larval stage on recovered goats. of 88 batches of larvae fed after the return of the goats' temperature to normal, or after challenge or immunosuppression, only the 9 batches of larvae fed during the febrile reaction, 2 batches applied 2 and 3 days respectively after recovery, and a single batch ...	1987	3448574
demonstration of colonies of cowdria ruminantium in midgut epithelial cells of amblyomma variegatum.	the development of colonies of cowdria ruminantium was studied in midgut epithelial cells of adult amblyomma variegatum that had become infected by feeding as nymphs on cattle with experimentally induced heart-water disease. colonies were not observed in gut tissues obtained from nymphs during the feeding period, but were present in midgut epithelial cells of ticks obtained at 15 days after they were replete through molting to the adult stage. colonies were small (1 to 10 micron) initially, but ...	1987	3551699
cowdria ruminantium: stability and preservation of the organism.	blood collected in either sodium heparin or disodium edetate vacutainers from febrile goats infected with 4 isolates of cowdria ruminantium and cryopreserved with 10% dimethyl sulphoxide at -70 degrees c and -196 degrees c was an effective stabilate to initiate heartwater infections in goats. a homogenized pool of whole amblyomma variegatum ticks in snyder's buffer, maintained at -196 degrees c, was used to infect a goat with c. ruminantium. liver and spleen collected from swiss mice infected wi ...	1987	3448560
epidemiology of heartwater in guadeloupe and in the caribbean.	at present, heartwater in the caribbean is known with certainty only on guadeloupe, marie galante and antigua; the first 2 islands are widely infected. the most important factors responsible for particular aspects of heartwater in guadeloupe are: cowdria ruminantium of high virulence. a very resistant cattle population (creole), not normally clinically affected. a fairly susceptible goat population (creole) (22% goats born in endemic areas die after experimental inoculation) which, fortunately, ...	1987	3448572
remote recognition of amblyomma variegatum habitats in guadeloupe using landsat-tm imagery.		1988	3232619
feeding performance of amblyomma variegatum (acarina: ixodidae) fed repeatedly on rabbits.	rabbits infested with different stages of amblyomma variegatum fabricius, 1794 became resistant to subsequent infestations by the same tick. resistance was manifested by a reduction of 73.6% in the mean engorged weight of female ticks by the 3rd infestation. by the 5th infestation, only 70% of the nymphs engorged and their mean engorged weight was 57.7% of that of nymphs fed on tick-naive control rabbits. in the case of larvae, there was a 22.8% reduction in their mean engorged weight by the 6th ...	1988	3197579
hosts and population dynamics of amblyomma variegatum (acari: ixodidae) on guadeloupe, french west indies.		1988	3351867
abnormal development of amblyomma variegatum (acarina: ixodidae).		1988	3351871
morphogenetic diapause in amblyomma variegatum (acari: ixodidae).	in southern africa, amblyomma variegatum fabricius is characterized by a strict seasonal activity. experiments were carried out to determine whether a diapause mechanism regulates this seasonality. engorged a.variegatum females were exposed to controlled laboratory conditions or natural field conditions at different times of the year. females exposed in a natural environment in september-october (short day) had significantly longer pre-oviposition periods than females exposed from november to ma ...	1988	2980187
[effect of natural infestation by amblyomma variegatum ticks on the growth of creole cattle and goats].		1988	3253862
[dermatophilus congolensis bovine dermatophilosis in the french west indies. iii. a comparison between infected and non-infected cattle].	the determination of the distinctive features between infected and uninfected cattle by dermatophilus has been performed among 93 bovine stock in la martinique, and 120 in la guadeloupe and saint-martin islands. nearly half of the herds had been or were infected. morbidity rates reach 33 per cent in la martinique and 29 per cent in la guadeloupe with a mortality ratio of 15 per cent and 5 per cent respectively. no frequency difference could be observed with respect to the season or the geographi ...	1989	2485539
effect of tick control on liveweight gain of cattle in central zambia.	field trials were carried out during 1982-86 in two different ecotypes in central zambia to determine the impact of tick control on the liveweight gain (lwg) of cattle. during the first 2 years of the trial a diamidide acaricide (amitraz) sprayed at weekly intervals caused periodic depression in lwg in young animals. thereafter a pyrethroid acaricide (cypermethrin) was used. during the 1984-85 tick season infestations of 50-120 adult amblyomma variegatum fabricius in untreated animals caused sig ...	1989	2519678
ecological aspects of cattle tick control in central zambia.	in ecological studies in central zambia, both climate and ecotype affected population dynamics of tick species. below average rainfall for several years caused a suppression in numbers of rhipicephalus appendiculatus neumann adults. reduction in rainfall leading to changes in grazing patterns is thought to have been responsible for an increase in numbers of amblyomma variegatum fabricius adults in a grassland habitat. there were reasonable correlations between numbers of each tick species on ind ...	1989	2519677
resistance and cross-resistance in guinea-pigs and rabbits to immature stages of ixodid ticks.	infestation of guinea-pigs and rabbits with larvae of any one of five species of ticks, rhipicephalus appendiculatus neumann, rhipicephalus evertsi evertsi neumann, amblyomma hebrauem koch, amblyomma variegatum fabricius and ixodes ricinus l., conferred resistance in the animals when exposed to subsequent infestations with the same tick species. resistance to infestations by other tick species was not observed.	1989	2519683
difference in vector competence of two species of sympatric ticks, amblyomma variegatum and rhipicephalus appendiculatus, for dugbe virus (nairovirus, bunyaviridae).	amblyomma variegatum was shown to be a competent vector of dugbe (dug) virus whereas rhipicephalus appendiculatus was not. when dug virus was taken up orally by a. variegatum nymphs, during capillary feeding, the virus replicated and persisted through moulting to the following adult stage. in contrast, although dug virus replicated in capillary fed r. appendiculatus nymphs, the virus did not persist trans-stadially into the adult stage. if the oral route of infection was by-passed by direct inoc ...	1989	2510418
vector capacity of rhipicephalus appendiculatus and amblyomma variegatum for thogoto and dhori viruses.	experimental studies were undertaken to ascertain the vector potential of rhipicephalus appendiculatus neumann and amblyomma variegatum fabricius for thogoto (tho) and dhori (dho) viruses, candidate members of the orthomyxoviridae. in the first set of experiments, ticks were infected orally by feeding on viraemic hamsters. tho virus replicated in r. appendiculatus and a. variegatum, persisted trans-stadially in both tick species, and was transmitted to susceptible hosts during feeding. in contra ...	1989	2519663
a mouse lethal dose assay for detection and titration of cowdria ruminantium (kwanyanga strain) in goats and ticks.	a mouse lethal dose assay was used to detect a mouse pathogenic strain (kwanyanga) of cowdria ruminantium, the etiological agent of heartwater in goats and ticks. the titer of the rickettsial organisms in goat blood was directly related to the febrile response of the goat and the rickettsia were undetectable after the fever subsided. the maximum rickettsial titer in goat blood was 10(3) mouse ld50 ml-1. cowdria-infected goat blood was shown to retain infectivity when held on ice for up to 2 h, b ...	1989	2705290
evaluation of the eradication program for amblyomma variegatum (acari:ixodidae) on puerto rico.	a cooperative effort between the united states department of agriculture, animal and plant health inspection service, veterinary services, the agricultural research service, and the department of agriculture, commonwealth government of puerto rico has been successful in eradicating amblyomma variegatum (fabricius) from the islands of puerto rico and vieques (an island municipality of puerto rico). application of acaricides to livestock and dogs at 14-day intervals for an 18-month period eliminat ...	1989	2707108
spectral sensitivity, absolute threshold, and visual field of two tick species, hyalomma dromedarii and amblyomma variegatum.	1. the spectral sensitivity in the wavelength range of 340-750 nm was determined by both a behavioral approach based on spontaneous positive phototaxis and the electroretinogram (erg). 2. concerning phototaxis the camel tick, hyalomma dromedarii, showed two sensitivity maxima, one in the uv range (ca. 380 nm) and another in the blue-green range (ca. 500 nm). at higher intensities the relative sensitivity was more pronounced in the uv and at lower intensities more pronounced in the blue-green (re ...	1989	2746548
acquired resistance to ixodid ticks induced by tick cement antigen.	antisera from guinea pigs made resistant to infestation with an ixodid tick of east and central africa, rhipicephalus appendiculatus, were used to identify the tick antigens they recognized by immunoblotting. most of the antigens were found in tick salivary glands and in tick attachment cement. antisera from r. appendiculatus-resistant guinea pigs also recognized some salivary-gland antigens in ticks of other species (r. pulchellus, r. evertsi, amblyomma variegatum and a. gemma). antibodies agai ...	1989	2758939
amblyomma variegatum ticks and the occurrence of bovine streptothricosis in antigua.	the association between the occurrence of amblyomma variegatum ticks and streptothricosis was studied on the caribbean island of antigua. the prevalence of streptothricosis was higher on animals having a. variegatum ticks compared to that of animals not infested with a. variegatum ticks. there was a steady increase in the prevalence of severe lesions as the level of infestation with adult a. variegatum ticks increased. however the distribution of skin lesions could not be related to the predilec ...	1989	2763757
monitoring of naturally acquired and artificially induced immunity to amblyomma variegatum and rhipicephalus appendiculatus ticks under field and laboratory conditions.	the ability of rabbits, goats and cattle to acquire immunity to the ixodid ticks amblyomma variegatum and rhipicephalus appendiculatus was studied under laboratory and field conditions. rabbits were successfully immunized with crude salivary gland extract (sge) and midgut extract (me) obtained from flat or partly fed female r. appendiculatus ticks. the lowest numbers of larvae were produced by females fed on rabbits immunized with unfed midgut extract. similar reductions in larval production cou ...	1989	2766896
dugbe virus replication in nymph and adult amblyomma variegatum.		1989	2772415
delayed-type hypersensitivity test for assessing tick-immune status of cattle in zambia.	delayed-type hypersensitivity skin reactions were used to assess the tick resistance status of tonga calves in zambia. the antigen used in the tests was a homogenate of unfed nymphal rhipicephalus appendiculatus which had been shown to give protective immunity in guinea pigs to adult female r appendiculatus. there was a significant negative correlation between the intensity of the reactions and the total number of ticks (amblyomma variegatum, r appendiculatus, hyalomma truncatum, boophilus decol ...	1989	2773195
[ticks of the family ixodidae in guinea and the isolation of arboviruses from them. ii. results of virologic and serologic research].	55697 ixodidae ticks of 35 species, belonging to 7 genera, were collected in guinea in 1981-1983. virological study of 29410 ticks was performed by intracerebral infection of newborn white mice. 49 viral strains were isolated. authors identified 38 strains of the 8 following arboviruses: dugbe, bhanja, cgl-congo (ecologically connected with ticks), blue tongue virus of sheep and abadine (association with ticks was found for the first time), kindia and forekarya (the new viruses). serological scr ...	1989	2811754
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
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