| the occurrence of streptothricosis and its association with amblyomma variegatum ticks in st. lucia. | cattle, horses, sheep and goats in all areas of st. lucia were examined to ascertain the prevalence and distribution of streptothricosis on the island and to investigate its association with the occurrence of amblyomma variegatum ticks. although the disease was found to occur throughout st. lucia it was more prevalent and generally of a more severe form in areas where a. variegatum ticks are present. a tick control programme in the north of the island appeared to have resulted in a dramatic redu ... | 1991 | 1789020 |
| [prevention of cowdriosis and cases of sheep diseases in the niayes region of senegal]. | sheep originating from an heartwater-free area were immunized by the infection and treatment method, using long-acting oxytetracycline. the animals were then exposed, together with control sheep to natural infection in an enzootic area. tick counts were made to monitor the infestation and establish a correlation between infestation by certain tick species, in particular amblyomma variegatum, and the occurrence of cowdriosis. in some cases of death associated with ehrlichiosis and anaplasmosis in ... | 1990 | 2218032 |
| [ticks and hemoparasitic diseases in cattle in senegal. iv. the southern sudan area]. | the authors report on the results of an investigation on ticks and hemoparasitoses of cattle, sheep and goats in the south sudanian area of senegal. systematic routine dipping against ticks of cattle, 40 sheep and 40 goats was set during 15 months, with a view to determine the population dynamics together with an acurate localization of the different species concerned. the following parasites were collected from these ruminants: amblyomma variegatum, boophilus geigyi, hyalomma truncatum, h. m. r ... | 1990 | 2218038 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| development, reproductive capacity and survival of amblyomma variegatum and boophilus decoloratus in relation to host resistance and climatic factors under field conditions. | to determine the developmental periods, fecundity and survival of amblyomma variegatum and boophilus decoloratus and the effect of host resistance, a study was carried out in the field at abernossa ranch in ethiopia using three breeds of cattle: arssi, boran and boran x friesian crossbreed. the investigation took place between october 1991 and september 1992. the developmental periods of both tick species were recorded. the hatching periods of larvae, engorgement, larvo-nymphal and nympho-adult ... | 1998 | 9637226 |
| a review of heartwater and the threat of introduction of cowdria ruminantium and amblyomma spp. ticks to the american mainland. | heartwater, caused by the rickettsial agent cowdria ruminantium, is one of the most devastating livestock diseases in sub-saharan africa. in addition to domestic cattle, sheep, and goats, a variety of nondomestic species can acquire subclinical and clinical infections. recent epidemiologic findings that demonstrate a long-term host carrier state in domestic and wild ruminants, intrastadial transmission by the tick vectors (amblyomma spp.), vertical transmission of the agent from cows to their ca ... | 1998 | 9732023 |
| comparison of efficacy of american and african amblyomma ticks as vectors of heartwater (cowdria ruminantium) infection by molecular analyses and transmission trials. | the ability of amblyomma americanum, amblyomma cajennense, amblyomma maculatum, and amblyomma variegatum to acquire and transmit cowdria ruminantium infection was investigated. uninfected nymphs were fed on clinically reacting c. ruminantium-infected sheep and then analyzed for infection by specific dna detection assays and by tick transmission trials. by polymerase chain reaction (pcr), the mean infection prevalence of a. maculatum ticks (50.7%) was similar to that of a. variegatum, elevage str ... | 2000 | 10701562 |
| tropical bont tick (amblyomma variegatum) eradication in the caribbean. the st. kitts experience. | the tropical bont tick (tbt) was first identified in st. kitts in 1978. initially, infestation was observed on cattle that developed a severe dermatitis. over a period of seven years, the tbt spread to most areas of the island, affecting cattle, sheep, and goats. the ruminant livestock population declined from, 6,000, 9,000, and 7,000 cattle, sheep, and goats, respectively, in 1984 to an estimated 400, 800, and 1,000, cattle, sheep, and goats in 1990. a project to control the tropical bont tick ... | 2000 | 11193641 |
| simultaneous detection of anaplasma and ehrlichia species in ruminants and detection of ehrlichia ruminantium in amblyomma variegatum ticks by reverse line blot hybridization. | the detection of anaplasma and ehrlichia species is usually based on species-specific pcr assays, since no assay is yet available which can detect and identify these species simultaneously. to this end, we developed a reverse line blot (rlb) assay for simultaneous detection and identification of anaplasma and ehrlichia species in domestic ruminants and ticks. in a pcr the hypervariable v1 region of the 16s ribosomal rna (rrna) gene was amplified with a set of primers unique for members of the ge ... | 2002 | 12243899 |
| development of a polyclonal competitive enzyme-linked immunosorbent assay for detection of antibodies to ehrlichia ruminantium. | a polyclonal competitive enzyme-linked immunosorbent assay (pc-elisa) is described for detection of antibodies to ehrlichia (cowdria) ruminantium by using a soluble extract of endothelial cell culture-derived e. ruminantium as the antigen and biotin-labeled polyclonal goat immunoglobulins as the competitor. for goats, the diagnostic sensitivity and specificity were both 100% with a cutoff of 80% inhibition (80 pi), with detection of antibodies for 550 days postinfection. for cattle, diagnostic s ... | 2003 | 12965926 |
| detection by two enzyme-linked immunosorbent assays of antibodies to ehrlichia ruminantium in field sera collected from sheep and cattle in ghana. | two serological tests for detection of antibodies to ehrlichia (previously cowdria) ruminantium, the causative agent of heartwater, were compared by using field sera collected from sheep and cattle as part of serosurveys in ghana. sera selected as either negative or positive by a new polyclonal competitive enzyme-linked immunosorbent assay (pc-elisa) were tested by the indirect map1-b elisa. cutoff values of 14 percent positivity (14 pp) for both ruminant species were obtained for the map1-b eli ... | 2003 | 12965927 |
| immunogenicity of ehrlichia ruminantium grown in tick cell lines. | ehrlichia (previously cowdria) ruminantium, the pathogen which causes heart-water in domestic and wild ruminants, can now be propagated in cell lines from one vector (amblyomma variegatum) and five non-vector (ixodes scapularis, i. ricinus, boophilus decoloratus, b. microplus and rhipicephalus appendiculatus) tick species. e. ruminantium isolates from west and south africa and the caribbean vary in their cell line preference, growth patterns and immunogenic capability. in laboratory trials, cert ... | 2002 | 14570129 |
| progress towards the eradication of amblyomma variegatum from the caribbean. | progress in the caribbean amblyomma program (cap) is reviewed since its inception in 1995 when regional eradication activities for amblyomma variegatum ticks were initiated using bayticol pour-on. technical achievements in the various islands were slow initially, and showed a wide diversity in attaining eradication targets. st. kitts, considered as a model program. eliminated the tropical bont tick (tbt) from most of the island in less than 3 years. however, the elimination of very low numbers o ... | 2002 | 14570141 |
| ehrlichia ruminantium seroprevalence in domestic ruminants in ghana; i. longitudinal survey in the greater accra region. | serum samples collected monthly over a 34-month period from cattle, sheep and goats in the greater accra region of ghana were tested for antibodies to ehrlichia (previously cowdria) ruminantium, the causative agent of heartwater, by polyclonal competitive elisa (pc-elisa). maternal antibodies, detected in about half of animals followed from under 1 month old, declined to negative levels within 2-4 months. amblyomma variegatum tick vectors were present on livestock in rural areas throughout the y ... | 2004 | 15145496 |
| point seroprevalence survey of ehrlichia ruminantium infection in small ruminants in the gambia. | using the map1-b enzyme-linked immunosorbent assay, we tested 1,318 serum samples collected from sheep and goats at 28 sites in the five divisions of the gambia to determine the ehrlichia ruminantium seroprevalence rates and to assess the risk for heartwater. about half (51.6%) of 639 sheep were positive, with seroprevalence rates per site varying between 6.9% and 100%. the highest seroprevalence was detected in the western part of the country (88.1% in the western division and 62.1% in the lowe ... | 2005 | 15817758 |
| tick-borne viruses. | at least 38 viral species are transmitted by ticks. virus-tick-vertebrate host relationships are highly specific and less than 10% of all tick species (argasidae and ixodidae) are known to play a role as vectors of arboviruses. however, a few tick species transmit several (e.g. ixodes ricinus, amblyomma variegatum) or many (i. uriae) tick-borne viruses. tick-borne viruses are found in six different virus families (asfarviridae, reoviridae, rhabdoviridae, orthomyxoviridae, bunyaviridae, flaviviri ... | 2004 | 15938513 |
| differential transcription of the major antigenic protein 1 multigene family of ehrlichia ruminantium in amblyomma variegatum ticks. | the rickettsial pathogen ehrlichia ruminantium causes heartwater in ruminants and is transmitted by ticks of the genus amblyomma. the map1 gene, encoding the major surface protein map1, is a member of a multigene family containing 16 paralogs. in order to investigate differential transcription of genes of the map1 multigene family in vivo in unfed and feeding ticks, rna was extracted from midguts and salivary glands of e. ruminantium-infected adult female amblyomma variegatum ticks and analysed ... | 2007 | 17321077 |
| genetic diversity of ehrlichia ruminantium in amblyomma variegatum ticks and small ruminants in the gambia determined by restriction fragment profile analysis. | understanding genetic diversity of ehrlichia ruminantium in host and vector populations is an important prerequisite to controlling heartwater by vaccination in traditional livestock systems in sub-saharan africa. we carried out a study in two phases: (i) evaluating the usefulness of the pcr-rflp assay based on the map1 coding sequence of e. ruminantium as a discriminatory tool to characterise genetic diversity, (ii) applying the technique to field samples from amblyomma variegatum ticks and sma ... | 2008 | 17646061 |
| longitudinal monitoring of ehrlichia ruminantium infection in gambian lambs and kids by pcs20 pcr and map1-b elisa. | the epidemiology of e. ruminantium infection in extensively managed young animals is not adequately understood. thus in this study, we monitored the onset (age at first infection) and kinetics of e. ruminantium infection and antibody response in extensively managed newborn lambs and kids at three sites in the gambia. | 2007 | 17662144 |
| variability and action mechanism of a family of anticomplement proteins in ixodes ricinus. | ticks are blood feeding arachnids that characteristically take a long blood meal. they must therefore counteract host defence mechanisms such as hemostasis, inflammation and the immune response. this is achieved by expressing batteries of salivary proteins coded by multigene families. | 2008 | 18167559 |
| a critical analysis of disease-associated dna polymorphisms in the genes of cattle, goat, sheep, and pig. | genetic variations through their effects on gene expression and protein function underlie disease susceptibility in farm animal species. the variations are in the form of single nucleotide polymorphisms, deletions/insertions of nucleotides or whole genes, gene or whole chromosomal rearrangements, gene duplications, and copy number polymorphisms or variants. they exert varying degrees of effects on gene action, such as substitution of an amino acid for another, shift in reading frame and prematur ... | 2008 | 18350334 |
| ectoparasites are the major causes of various types of skin lesions in small ruminants in ethiopia. | ectoparasites are the major causes of skin lesions in animals. clinical, skin scraping examination, and histopathological studies were conducted to identify and characterize skin lesions in small ruminants caused by ectoparasites. mange mites, lice, sheep keds, and ticks were collected from the skin of affected animals for species identification. skin biopsies were collected from affected part of the skin and fixed in 10% neutral buffered formalin for histopathology. of 1,000 sheep and 600 goats ... | 2010 | 20195754 |
| survey of ixodid ticks in domestic ruminants in bedelle district, southwestern ethiopia. | a survey aimed at determining the status of ticks in cattle, sheep and goats in bedelle district (southwestern ethiopia) was carried out from november 2007 to april 2008. out of the total 330 animals examined, 314 (95.2%) were found to be infested (harbouring of at least a single tick). high rates of infestations were recorded across all three host species. factors like month of collection, age and sex of host species did not show significant association with infestation rates. a total of 5,507 ... | 2010 | 20563884 |
| tick-borne rickettsioses, neglected emerging diseases in rural senegal. | rickettsioses are one of the most important causes of systemic febrile illness among travelers from developed countries, but little is known about their incidence in indigenous populations, especially in west africa. | 2010 | 20856858 |
| rickettsia africae in amblyomma variegatum and domestic ruminants on eight caribbean islands. | we used pcrs with omp a primers to determine if spotted fever group rickettsiae occurred in amblyomma variegatum from 6 caribbean islands. positive amplicons were obtained from ticks from the u.s. virgin islands (9/18; 50%), dominica (39/171; 30%), montserrat (2/5; 40%), nevis (17/34; 50%), st. kitts (46/227; 20%), and st. lucia (1/14; 7%). sequences for a convenience sample of reaction products obtained from a. variegatum on st. kitts (7), american virgin islands (4), montserrat (2), and st. lu ... | 2010 | 21158615 |
| ehrlichia ruminantium in amblyomma variegatum and domestic ruminants in the caribbean. | the highly sensitive nested pcs20 polymerase chain reaction assay for ehrlichia ruminantium was negative on 506 amblyomma variegatum from caribbean islands where clinical heartwater has not been reported, mainly the united states virgin islands (18), dominica (170), montserrat (5), nevis (34), st. kitts (262), and st. lucia (17). positive results were obtained with positive controls (crystal springs strain) and a. variegatum from countries in africa where infections are endemic, mainly tanzania ... | 2011 | 21485394 |
| the recent evolution of a maternally-inherited endosymbiont of ticks led to the emergence of the q fever pathogen, coxiella burnetii. | q fever is a highly infectious disease with a worldwide distribution. its causative agent, the intracellular bacterium coxiella burnetii, infects a variety of vertebrate species, including humans. its evolutionary origin remains almost entirely unknown and uncertainty persists regarding the identity and lifestyle of its ancestors. a few tick species were recently found to harbor maternally-inherited coxiella-like organisms engaged in symbiotic interactions, but their relationships to the q fever ... | 2015 | 25978383 |