TitleAbstractYear(sorted ascending)
prevalence of borrelia (spirochaetaceae) spirochetes in texas ticks.between 1990 and 1992, ticks from eight texas parks were collected and analyzed to determine the prevalence of spirochete-infected ticks. borrelia spirochetes were detected in 1.03% of 5,141 amblyomma americanum (l.) adults examined, a species texas residents often encounter. no spirochetes were observed in the other tick species tested.19948189421
aponomma (bothriocroton) glebopalma, n. subgen., n. sp., and amblyomma glauerti n. sp. (acari: ixodida: ixodidae), parasites of monitor lizards (varanidae) in australia.aponomma (bothriocroton) glebopalma, n. subgen., n. sp., and amblyomma glauerti, n. sp. (acari: ixodidae), are described from the monitor lizards varanus glebopalma mitchell and varanus glauerti mertens in western australia and the northern territory, australia. the new subgenus is erected to accomodate a. (bothriocroton) glebopalma, a new species with a deeply pitted and pilose scutum in both the adult and immature stages, unlike all other described species of aponomma. this new species is foun ...19948158616
respiratory gas exchange in the tick amblyomma hebraeum (acari: ixodidae).respiratory gas exchange was studied in unfed adult amblyomma hebraeum koch. carbon dioxide emission was measured at 25 degrees c using flow-through respirometry to determine standard metabolic rate and the temporal pattern of gaseous emission. the standard co2 production rate (svco2) of inactive ticks was 0.0135 +/- 0.0085 ml g-1 h-1, and the standard o2 consumption rate (svo2) was 0.0158 +/- 0.0097 ml g-1 h-1. ventilation was discontinuous and was characterized by periodic bursts of co2 emissi ...19948158626
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 ...19948158630
seasonal and annual abundance of amblyomma americanum (acari: ixodidae) in central georgia.seasonal and annual changes in the abundance of amblyomma americanum (l.) larvae, nymphs, and adults were monitored over a 5-yr period in the piedmont physiographic region of georgia. tick abundance was monitored with cloth drags (all life stages) and co2-baited cloth panels (nymphs and adults) monthly during march through september from 1987 through 1991. larvae appeared in substantial numbers in july and were most numerous in august and september. small numbers of unfed larvae apparently overw ...19948158632
influence of annual and biennial prescribed burning during march on the abundance of amblyomma americanum (acari: ixodidae) in central georgia.a 5-yr study to evaluate the influence of annual and biennial prescribed burning in march on the abundance of amblyomma americanum (l.) was conducted on oconee wildlife management area in the piedmont physiographic region of georgia. tick abundance on plots embedded in larger burned and unburned areas were monitored with cloth drags and co2-baited cloth panels monthly during march through september from 1987 through 1991. annual and biennial prescribed burning from 1988 to 1991 significantly red ...19948158633
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 ...19948081294
genome size and organization in the ixodid tick amblyomma americanum (l.).we used dna reassociation kinetics to determine genome size and organization in the ixodid tick amblyomma americanum. we calculated the genome size of a. americanum to be approximately 1.08 pg or 1.04 x 10(9) base pairs and to consist of 35.8% unique dna, 4.2% foldback sequences, 17.9% highly repetitive sequences, and 42.1% moderately repetitive sequences. comparison of the reassociation kinetics of long and short fragments revealed repetitive sequences to be distributed in a pattern of long per ...19948069417
serologic diagnosis of human monocytic ehrlichiosis by immunoblot analysis.human monocytic ehrlichiosis is caused by ehrlichia chaffeensis, an intracellular bacterium probably transmitted by the tick amblyomma americanum in the united states. despite its lack of specificity in discriminating among infections by closely related ehrlichia spp., immunofluorescence assay (ifa) is the most frequently used serological diagnostic method. to improve the specificity of the serological diagnosis, we compared antigenic profile of e. canis and e. chaffeensis antigen with homologou ...19948556515
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 ...19948151519
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 ...19947973080
[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 ...19947991897
[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 ...19948003897
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 ...19948009646
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 ...19948009647
influence of environmental factors on oviposition and egg development in amblyomma limbatum and aponomma hydrosauri (acari: ixodidae).this study examined the influence of temperature and light on the length of the pre-oviposition period of engorged females of two australian ixodid ticks, amblyomma limbatum and aponomma hydrosauri. the hatching success and development time of eggs of both species were also compared at different temperatures and relative humidities. darkness was found to have no effect on the duration of the pre-oviposition time or reproductive output of females of either species. in contrast, the preoviposition ...19948021110
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 ...19948057326
ticks (acari: ixodidae) collected from small and medium-sized kansas species of hard-bodied ticks were collected from 20 species of small and medium-sized mammals in kansas; amblyomma americanum l., dermacentor variabilis (say), haemaphysalis leporispalustris (packard), ixodes cookei packard, i. kingi bishopp, i. sculptus neumann, and i. texanus banks. dermacentor variabilis was found statewide, a. americanum only in the eastern one-third of the state, and the ixodes spp. and h. leporispalustris were widely scattered. the most common tick found was d. varia ...19948057327
identification of rickettsiae from ticks collected in the central african republic using the polymerase chain reaction.spotted fever rickettsiosis have been identified on the african continent since their historical description in 1909. however, only rickettsia conorii and r. africae have been described in africa, and the current techniques for the detection of rickettsiae in ticks are difficult to apply in large field studies. we report here a preliminary study using genomic amplification by the polymerase chain reaction followed by restriction fragment length polymorphism (pcr-rflp) analysis directly on 310 cr ...19947908504
a new pathogenic spotted fever group rickettsia from africa.a spotted fever group (sfg) rickettsia was isolated in zimbabwe from a patient with tick-bite, fever, headache and regional lymphadenopathy. a further six isolates were obtained from amblyomma hebraeum ticks collected in zimbabwe. these human and tick isolates were indistinguishable from each other, and from an ethiopian sfg rickettsia, by microimmunofluorescence (mif), sodium dodecyl sulphate-polyacrylamide gel electrophoresis (sds-page), western blotting and polymerase chain reaction followed ...19947911846
isotopes as host blood markers to measure blood intake by feeding ticks (acari: ixodidae).we have modified an experimental technique in which two different isotopes (cr51 and i125) were used simultaneously as blood markers for determining the amount of blood removed by feeding ticks. this method enables us to measure separately and directly the volumes of red blood cells and plasma in ticks and to calculate the ratio between the two parameters (concentrating ability). the concentration of red blood cells in nymphs of amblyomma hebraeum kock and rhipicephalus appendiculatus neumann an ...19947932595
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 ...19947932599
integrated management strategies for amblyomma americanum (acari: ixodidae) on pastured beef on tick control and knowledge of the damage caused to beef cattle by tick feeding were incorporated into a computerized dynamic life table model (lstsim) for amblyomma americanum (l.). simulations were made to determine economically feasible, 5-yr integrated pest management (ipm) strategies for a. americanum in forage areas utilized by bos taurus, bos indicus, and crossbred cattle (b. taurus x b. indicus). the effects of host resistance, pasture rotation, habitat conversion, topical acarici ...19947932604
evidence supporting the presence of borrelia burgdorferi in missouri.although lyme disease is commonly seen in the southcentral united states, the epidemiology of the disease is poorly defined there. the purpose of this study was to document the presence of borrelia burgdorferi in ticks collected in southeastern missouri and around the city of st. louis. spirochetes were detected and identified as b. burgdorferi by immunofluorescent antibody (ifa) tests using the monoclonal antibody h5332 in 1.9% of amblyomma americanum and 2.0% of dermacentor variabilis ticks co ...19947943575
seasonal prevalence of ticks and their association with dermatophilosis in cattle on the accra plains of ghana.the seasonal abundance of adult ticks on cattle and their association with dermatophilosis were investigated in five herds on the coastal plains of ghana over a 26-month period. four genera, amblyomma, boophilus, rhipicephalus and hyalomma were identified, a. variegatum being the predominant species occurring throughout the year with two peaks of infestation, one in april-may and the other in november. a significant positive correlation was revealed between a. variegatum and dermatophilosis in f ...19947863064
using cuticular hydrocarbon composition to elucidate phylogenies in tick populations (acari: ixodidae).cuticular hydrocarbon composition is used to explain hypothetical phylogenies among sympatric and allopatric populations of amblyomma cajennense, a. variegatum and ixodes ricinus tick species. the method proposed here uses a parsimony analysis of endemicity by disjunct biochemical data (paedb) based in the pattern of cuticular hydrocarbons. the advantage of our approach is that information contained in fragments that are not conserved in all the individuals of a populations need not be discarded ...19947863854
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 ...19947879382
helminth and arthropod parasites of indigenous goats in the northern transvaal.helminth and arthropod parasites of 60 female indigenous goats of three age groups on a farm in the northern transvaal were collected, identified and counted. anoplocephalid tapeworms were present in the two younger groups of goats, while larvae of taenia hydatigena were recovered from all three groups. eight species and two genera of nematodes were found in the youngest goats, five species and three genera in the middle group and six species and two genera in the oldest goats. strongyloides pap ...19947898893
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 ...19947628240
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, ...19947628253
the effect of rainfall on tick challenge at kyle recreational park, zimbabwe.the effect of rainfall pattern on tick challenge was investigated at kyle recreational park, zimbabwe, from 1991 to 1992 using drag and removal plot methods to sample environmental tick density. the abundance of adults and nymphs of the brown ear-tick rhipicephalus appendiculatus and larvae of the bont tick amblyomma hebraeum was positively correlated with monthly rainfall, whereas no relationship with rainfall was revealed for larval r. appendiculatus, adults of the red-legged tick r. evertsi, ...19947628257
reproductive interactions between two australian reptile tick south australia the two tick species amblyomma limbatum and aponomma hydrosauri share the same common reptile host species, but have allopatric distributions which abut along a narrow parapatric boundary. reproductive interference is a mechanism that has previously been suggested could contribute to maintaining the boundary. populations of each species were established in pens within the range of aponomma hydrosauri. pens held either each species alone, or the two species together. the perfor ...19947628259
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 ...19947638002
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 ...19947711310
[changes in the bactericidal activity of the cementing fraction in ixodid tick saliva under the influence of the presence of the tick-borne encephalitis virus].it is demonstrated that the abundance of bactericidal compounds in the salivary cement plug of ixodid ticks is changing under the influence of virulent tick-borne encephalitis virus (tbev) reproduction in their bodies. tbev infected ixodes persulcatus cement plug-forming lytic zone size enlarged in comparison with the naive tick one whereas micrococcus lysodeikticus lytic zones induced by the cement plug of tbev infected amblyomma hebraeum nymphs or rhipicephalus appendiculatus females reduced c ...19947715548
ectoparasites of opossums and raccoons in southeastern georgia.twelve species of ectoparasites (four fleas, three ticks, three chiggers, one macronyssid mite, and one atopomelid mite) were recovered from 42 opossums, didelphis virginiana kerr, live-trapped from september 1992 through april 1994 in southeastern georgia. the fleas, ctenocephalides felis (bouché) (prevalence = 19%) and polygenis gwyni (c. fox) (36%); the ticks, dermacentor variabilis (say) (40%) and ixodes scapularis say (19%); and the macronyssid mite, ornithonyssus wernecki (fonseca) (21%), ...19947815408
notes on the biology of amblyomma dissimile koch, 1844 (acari:ixodida) on bufo marinus (linnaeus, 1758) from brazil.amblyomma dissimile is a common ectoparasite of cold blooded animals and is an accidental ectoparasite of some wild mammals. details of the biology of specimens from the state of amapá were studied in the laboratory in a humidity chamber at an average environmental temperature of 19.5 degrees c, using bufo marinus as host for the time in brazil. we also report the first record of this species in the state of minas gerais.19947823816
seasonal variation of ticks (ixodidae) in bos taurus x bos indicus cattle under rotational grazing in forested and deforested habitats in northwestern argentina.the seasonal occurrence of ticks infesting cattle was monitored in a bos taurus x bos indicus commercial herd fed on a combination of native grasses and annual pastures in northwestern argentina. the number of female ticks (boophilus and amblyomma) and the proportion of cattle infested with larvae and nymphs of amblyomma ticks were recorded from a sample of 15 cows in 24 visits at intervals of 21-50 days from 5 december 1986 to 24 november 1988. the cattle were maintained on native grasses in fo ...19947839563
rearing amblyomma variegatum ticks in the laboratory: a simple technique to enhance attachment. 19947841497
the detection of antibodies cross-reacting with cowdria ruminantium in the sera of domestic ruminants in regions of south africa where amblyomma hebraeum does not occur.high levels of seropositivity, in all probability attributable to ehrlichia, were recorded in the serum of domestic ruminants throughout districts in south africa where amblyomma hebraeum, the vector of the heartwater agent, does not occur. the antibodies, detected with the indirect fluorescent antibody (ifa) and the indirect elisa tests, cross-reacted with cowdria ruminantium, which was used as antigen in both tests. a combination of the ifa and elisa tests, currently employed to detect antibod ...19947501358
seasonal incidence and hemoparasite infection rates of ixodid ticks (acari: ixodidae) detached from cattle in costa determine the tick species hindering the cattle industry in costa rica and to assess infection rates of ticks with three important hemoparasite species, cattle were monitored during a period of six months (october 1992-march 1993). four farms were located in the dry pacific region of the canton of tilarán and a fifth farm on the slopes of the poás volcano in a cool tropical cloud-forest ecosystem. on each farm 3 to 5 animals of 6 to 24 months of age were selected at random. all ticks were rem ...19947501871
effects of tick infestation and tick-borne disease infections (heartwater, anaplasmosis and babesiosis) on the lactation and weight gain of mashona cattle in south-eastern zimbabwe.the effects of ticks and tick-borne disease infections on the lactation and weight gain of mashona cattle were studied at mbizi quarantine station in the south-eastern lowveld of zimbabwe. twenty-nine mashona cows were allocated to 2 balanced groups and kept in separate paddocks at a stocking rate of one animal per 8 ha. one group received regular acaricide treatment to control bont (amblyomma hebraeum) and other ticks. the other group was left untreated. the cows were artificially inseminated. ...19957502343
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.19957502345
evidence of common and genus-specific epitopes on ornithodoros spp. tick (acari: argasidae) salivary zealand white rabbits were repeatedly infested with ornithodoros turicata (duges), ornithodoros talaje (guérin-méneville), and ornithodoros coriaceus (koch) at 2-wk intervals. blood samples were taken from each animal 10 d after each infestation and the titer of anti-tick antibody was determined by enzyme-linked immunosorbent assay. subsequent cross-reactivity studies demonstrated that the antitick antisera nonspecifically bound to salivary gland extract proteins prepared from several other ...19957544412
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 ...19957571338
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 ...19957589273
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 ...19957597781
review of the molecular biology of cowdria ruminantium.cowdria ruminantium is a rickettsial agent which causes heartwater, an economically important disease of livestock in the tropics and the caribbean. significant advances have been made in the molecular biology of c. ruminantium since its reproducible propagation in vitro in bovine endothelial cells. these advances have been targeted towards the development of improved vaccines and diagnostic tests. several immunogenic proteins of c. ruminantium have been identified and monoclonal antibodies have ...19957597792
seasonal abundance of the tortoise tick amblyomma marmoreum (acari: ixodidae) on the leopard tortoise, geochelone paradalis.a survey of amblyomma marmoreum koch ticks recorded from the leopard tortoise, geochelone paradalis bell, in the national zoological gardens, pretoria, south africa, was carried out over a 19-mo period. no significant differences were found between the tick burdens on male and female tortoises. a. marmoreum showed a clear seasonal pattern of abundance. larvae were present on the tortoise host during late summer, with a peak in february and march; nymphs were abundant during winter, with a peak i ...19957608922
activity of repellents applied to skin for protection against amblyomma americanum and ixodes scapularis ticks (acari: ixodidae).twenty-nine repellents were tested on human skin for duration of activity as protectants against nymphal lone star ticks (amblyomma americanum) and against black-legged or deer ticks (ixodes scapularis say). eleven of these repellents, including deet, provided > 2 h of protection against the lone star tick. one repellent, 1-(3-cyclohexenyl-ylcarbonyl) piperidine, was effective > or = 4 h. four repellents (2 pyridines and 2 piperidines with protection lasting 2.3-3 h) showed acaricidal activity t ...19957616181
review of the ixodid tick fauna (acari: ixodidae) of vietnam.forty-eight species making up the tick fauna of vietnam (genera ixodes, ixodes, amblyomma, aponomma, haemaphysalis, dermacentor, hyalomma, nosomma, rhipicephalus, boophilus) are reviewed, including one genus and nine species that are new records for vietnam, as well as four species described by the author.19957616517
experimental transmission of ehrlichia chaffeensis (rickettsiales: ehrlichieae) among white-tailed deer by amblyomma americanum (acari: ixodidae).ehrlichia chaffeensis anderson, dawson & wilson, causative agent of human (predominantly monocytic) ehrlichiosis, was successfully transmitted experimentally by amblyomma americanum (l.) to white-tailed deer, odocoileus virginianus (zimmerman). deer were needle-exposed intravenously to e. chaffeensis in tissue-culture canine macrophage (dh82) cells, and 11 d later were exposed to laboratory-reared a. americanum larvae, nymphs, and adults for acquisition feeding. three months after this feeding, ...19957616529
ehrlichiosis in a golf-oriented retirement community.ehrlichiosis due to ehrlichia chaffeensis usually occurs sporadically or in small clusters, with an annual incidence estimated at 3 to 5 cases per 100,000 population in areas of endemic disease. the putative principal vector is the lone star tick (amblyomma americanum). we investigated an outbreak of ehrlichiosis that occurred in june 1993 among members of a golf-oriented retirement community (community a) in tennessee. the community is densely wooded and borders a wildlife-management area where ...19957616991
epidemiologic and diagnostic studies of patients with suspected early lyme disease, missouri, 1990-1993.a retrospective case-control study investigated 45 missouri outpatients with annular rashes meeting a surveillance case definition for erythema migrans and with onset in 1990-1991. risk factors included being male, living near a body of water, and hunting. twenty patients (44%) associated their rash with the bite of a tick; of these, 5 described an adult amblyomma americanum. a typical rash was described as expanding over time and measuring 8 cm in diameter at 4 days after onset. mild constituti ...19957622891
biosynthesis of salivary prostaglandins in the lone star tick, amblyomma americanum.dopamine-induced saliva from ticks fed [3h]arachidonic acid contained the radiolabelled prostaglandins e2, f2 alpha, d2, and b2, the latter probably derived from pge2 owing to the alkalinity of tick saliva. prostaglandin synthetase (pgs) activity in the salivary gland homogenate from the lone star tick, amblyomma americanum, could not be detected by standard radiometric methodologies successfully employed for tissues from many animal species, including numerous arthropods. modifications to the a ...19957627205
bacteriocidal qualities of ixodid tick (acarina: ixodidae) salivary cement plugs and their changes under the influence of a viral tick-borne pathogen.the abundance of bacteriocidal compounds contained in the salivary cement plug of ixodid ticks was changed because of the reproduction of tick-borne encephalitis virus (tbev) in their bodies. the size of tbev-infected ixodes persulcatus shulze lytic zone surrounding the cement plug enlarged to that of naive ticks, whereas micrococcus lysodeikticus (cohn) lytic zones induced by the cement plugs of tbev-infected amblyomma hebraeum koch nymphs or rhipicephalus appendiculatus neumann females were re ...19957473610
detection of cowdria ruminantium in blood and bone marrow samples from clinically normal, free-ranging zimbabwean wild ungulates.cowdria ruminantium causes severe, often fatal disease in domestic ruminants, whereas wildlife species usually are not affected. blood and bone marrow samples from healthy, free-ranging zimbabwean ungulates were taken during translocation from areas harboring amblyomma ticks and tested for the presence of c. ruminantium, using a pcr assay based on the c. ruminantium map1 gene. positive reactions were obtained in tsessebe (damaliscus lunatus), waterbuck (kobus ellipsiprymnus), and impala (aepycer ...19957494060
ecdysteroid titre and metabolism and cuticle deposition during embryogenesis of the ixodid tick amblyomma hebraeum (koch).three embryonic cuticles are formed before larval cuticle deposition during embryonic development of amblyomma hebraeum. the quantity of radioimmunoassay-positive material varied between 50 and 200 pg ecdysone equivalents per mg, but no significant peaks were detected. maternally incorporated [3h]-20-hydroxyecdysone and [3h]-ecdysone contained in freshly laid eggs appear to be conjugated to c-22 fatty acid esters and 3 alpha epimers of those esters, and, thus, appear doubly inactivated. in addit ...19957858939
physiological responses of beef cattle to gulf coast tick (acari: ixodidae) infestations.nine yearling crossbred beef steers, bos taurus l., were used to examine physiological responses to gulf coast tick, amblyomma maculatum koch, infestation. steers were stanchioned indoors in individual environmentally controlled rooms. on day 0, each animal received 0, 25, or 75 pairs of ticks. physiological variables measured daily were feed intake, heart rates, rectal temperatures, and respiration rates. blood samples were collected from each animal on days 7, 21, and 42 for serum constituent ...19957722083
uptake, incorporation and redistribution of arachidonic acid in isolated salivary glands of the lone star tick.the ability of isolated salivary glands from the lone star tick, amblyomma americanum, to take up, incorporate and redistribute [3h]arachidonic acid was examined. uptake of arachidonic acid was concentration dependent--a single salivary gland incorporated up to approximately 2.8 micrograms arachidonic acid in 60 min. over 90% of the [3h]arachidonate entering the glands was esterified and found only in the phospholipid (approximately 80%) and triglyceride (approximately 10%). essentially no radio ...19957742831
detection of rickettsia japonica in haemaphysalis longicornis ticks by restriction fragment length polymorphism of pcr product.pcr was applied to the detection of rickettsia japonica, the causative agent of oriental spotted fever (osf), in ticks collected at two sites of the muroto area on shikoku island, a major area in japan where osf is endemic. primer pair rr190.70p and rr190.602n of the r. rickettsii 190-kda antigen gene sequence of regnery and others (r.l. regnery, c.l. spruill, and b.d. plikaytis, j. bacteriol. 173:1576-1589, 1991) primed the dna extracted from haemaphysalis longicornis ticks but not those extrac ...19957790445
origin of arachidonic acid in the salivary glands of the lone star tick, amblyomma, americanum.the contribution of synthesis and dietary sequestration to the high arachidonate content of the lone star tick, amblyomma americanum, salivary glands was investigated by assessing the salivary metabolites of various radiolabeled fatty acid substrates administered to partially fed females. a portion of each of the fatty acids studied was incorporated into the fatty acid moiety of the phospholipid fraction. [14c]acetate was metabolized only into myristic, palmitic, palmitoleic, steric, and oleic a ...19957711753
host-seeking behaviour by australian ticks (acari: ixodidae) with differing host specificities.ticks generally detach from their hosts into sites where they are later exposed to host species which may or may not be suitable for infestation. the question of how four species of ixodid ticks, with differing specificities, behave towards such potential host species was examined. observations of the generalists, aponomma hydrosauri and amblyomma limbatum and the specialists, aponomma fimbriatum and aponomma concolor, showed that the generalists were attracted to a wider range of potential host ...19957641569
evaluation of ixodes scapularis, amblyomma americanum, and dermacentor variabilis (acari: ixodidae) from georgia as vectors of a florida strain of the lyme disease spirochete, borrelia burgdorferi.the ability of three common tick species from georgia to maintain and transmit the causative agent of lyme disease, borrelia burgdorferi, was compared under laboratory conditions. a b. burgdorferi cotton rat isolate (mi-6) from florida was selected as a strain from the south, and the sh2-82 isolate from new york was used as a positive control. amblyomma americanum (l.) and dermacentor variabilis (say) did not transmit the mi-6 isolate from inoculated hamsters to naive laboratory mice, and nympha ...19957650697
lower temperature limits for activity of several ixodid ticks (acari: ixodidae): effects of body size and rate of temperature change.uncoordinated activity threshold temperature, the temperature below which ticks can no longer seek a host in a coordinated manner, and the activity threshold temperature, when all activity ceases, were examined for three species of ticks found in coastal sections of new york. the mean uncoordinated activity threshold and activity threshold temperatures were determined for nymphal, female and male ixodes scapularis say, nymphal, female, and male amblyomma americanum (l.), and for female and male ...19957650705
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 ( ...19957652946
regulation of free arachidonic acid levels in isolated salivary glands from the lone star tick: a role for important regulatory step for prostaglandin synthesis is the availability of the precursor, free arachidonic acid (aa). in isolated salivary glands of the lone star tick, amblyomma americanum (l.), the level of free aa appears to depend on higher phospholipase a2 (pla2) activity rather than decreased rates of re-esterification by lysophosphatide acyl transferase (lat). this conclusion is supported by experiments where inhibition of lat with merthiolate was without effect, while the calcium io ...19957655056
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 ...19957675530
epidemiological aspects of equine babesioses in a herd of horses in brazil.epidemiological studies of babesia equi and b. caballi were undertaken in a herd of 120 pastured horses in rio de janeiro, brazil. the area where the horses were held was shown to be highly endemic for both babesia spp., i.e. the prevalence of b. equi antibodies in horses aged 6 months or older ranged from 90.6% to 100% as determined by the immunofluorescence antibody (ifa) test, and the prevalence of b. caballi antibodies as determined by western blot ranged from 59.4% to 65.5%. from the herd, ...19957676590
borrelia burgdorferi in eastern virginia: comparison between a coastal and inland virginia, borrelia burgdorferi was more prevalent in a site along the atlantic ocean, near maryland, than in an inland site near williamsburg and yorktown. at the coastal site on assateague island, b. burgdorferi was isolated from 4.2% of 475 animals sampled, including four species of small mammals. serologic tests indicated that 25-37% of the small rodents assayed had been exposed to b. burgdorferi. immunofluorescence antibody assays specific for b. burgdorferi showed spirochete infection in ...19957677212
development and evaluation of pcr assay for detection of low levels of cowdria ruminantium infection in amblyomma ticks not detected by dna probe.the sensitivities of a pcr assay and a dna probe assay were compared for the detection of cowdria ruminantium in amblyomma ticks that were fed on c. ruminantium-infected, clinically reacting, and recovered carrier animals. the pcr assay and dna probe detected infection in 86.0 and 37.0%, respectively, of 100 ticks fed on a febrile animal. in 75 ticks fed on carrier animals, pcr and the dna probe detected infection in 28.0 and 1.33% of ticks, respectively. this demonstrates that the dna probe has ...19957699036
an investigation into the health status and diseases of wild dogs (lycaon pictus) in the kruger national park.many factors have been cited as possible reasons for the decline in the number of wild dogs (lycaon pictus), but few studies have provided supportive data. between 1990 and 1993, the dynamics of 10 wild dog packs in the southern district of the kruger national park in south africa were monitored. casual observations of the causes of disease and mortality in the entire population were also recorded. during the same period, 46 wild dogs were immobilised, weighed, and subjected to physical examinat ...19957629782
cytosystematics of five north american amblyomma (acarina: ixodidae) species.the karyotypes of 5 species of amblyomma ticks found in north america were examined for the presence and location of constitutive heterochromatin (c-bands). all specimens examined had 20 autosomes and an xx:xo sex-determining system, with the x being the largest element in the karyotype. except as noted in text, the autosomes of all species were acrocentric and heterochromatin was restricted to the centromeric region. the third largest autosome in 4 of the 5 species displayed a consistent band o ...19957876973
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 ...19958532370
the relationship between tick (amblyomma hebraeum) infestation and immunity to heartwater (cowdria ruminantium infection) in calves in zimbabwe.the occurrence of endemic stability for heartwater (cowdria ruminantium infection) is a controversial issue, because the means by which young cattle and other neonatal ruminants become infected and acquire immunity to the disease have never been adequately explained. we conducted a study in a heartwater-endemic area in southeastern zimbabwe to investigate the relationships between calf immunity to c. ruminatium, infestations of the tick vector amblyomma hebraeum and dam, colostral and calf antib ...19958533273
some properties of the ecdysteroid receptor in the salivary gland of the ixodid tick, amblyomma hebraeum.salivary gland degeneration in ixodid ticks is triggered by an ecdysteroid hormone. we used [3h]ponasterone a (poa) as a specific ligand to detect the ecdysteroid receptor in the salivary glands of large, partially fed female ticks (amblyomma hebraeum koch; acari: ixodidae). binding of [3h]poa was thermolabile and sensitive to pronase, but not to dnase or rnase, indicating that the ligand binds to a protein. scatchard analysis of [3h]poa binding strongly suggested the presence of an ecdysteroid ...19958536946
physiological and nutritional responses of steers infested with varying densities of amblyomma americanum (acari: ixodidae).the effects of varying densities of lone star tick, amblyomma americanum (l.), on measured physiological parameters of beef cattle in a controlled environment was determined. steers were infested with either 0, 20, 60, or 120 pairs of adult ticks. heart rate, respiration, rectal temperature, fecal and urine excretions, and water and feed consumption were monitored daily. blood samples were taken every 3rd d to measure cortisol, total proteins, urea nitrogen, and glucose levels. hematocrits were ...19958537543
prostaglandin biosynthesis and subcellular localization of prostaglandin h synthase activity in the lone star tick, amblyomma americanum.we report on prostaglandin (pg) biosynthesis in the lone star tick, amblyomma americanum. in vitro preparations of whole female ticks and internal tissues were competent to biosynthesize four pgs: pga2/pgb2, pgd2, pge2, pgf2 alpha. pga2/pgb2 was the major product under optimal conditions. pg biosynthesis by whole tick and internal tissues were sensitive to incubation conditions including, protein concentration, time, temperature, ph, and presence of a co-factor cocktail composed of reduced gluta ...19958541884
the life-cycle of the bont tick amblyomma hebraeum in vitro.the life-cycle of the hard tick amblyomma hebraeum was completed in vitro by feeding all life-stages of the tick through silicone membranes on bovine blood from an abattoir. ticks were placed in a simple feeder membranes on bovine blood from an abattoir. ticks were placed in a simple feeder consisting of a honey jar containing the blood with a glass tube insert (o.d. 42 mm) across the end of which the membrane was stretched. this feeding unit was held in a water bath (38 degrees c). larvae and n ...19958550288
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 ...19958551500
field evaluation of deet and a piperidine repellent (ai3-37220) against amblyomma americanum (acari: ixodidae).repellent efficacy of deet (n,n-diethyl-3-methylbenzamide) and a piperidine, ai3-37220, was evaluated topically on human volunteers against lone star tick, amblyomma americanum (l.), nymphs and adults in the field. ai3-37220, at 0.5 mg/cm2, provided > 90% repellency against adult and nymphal ticks over a 6-h test period and showed significantly better repellent efficacy than deet. deet, at the same concentration, provided 85% repellency at 0 h and deteriorated to 55% repellency at 6 h.19958551512
clinical disorders observed in anteaters (myrmecophagidae, edentata) in captivity.the major health problems found in 103 captive lesser anteaters (tamandua tetradactyla) and giant anteaters (myrmecophaga tridactyla), family myrmecophagidae, are presented and correlated with management. the most common of 200 recorded clinical disorders involved the digestive system (26%), nutritional deficiency (20%), injury (15.5%), respiratory system (10%), skin (7%) and circulatory system (4.5%), but 13% of the cases were inconclusive. parasites were identified in 48.5% of faecal samples, ...19958560755
hemocytic rickettsia-like organisms in ticks: serologic reactivity with antisera to ehrlichiae and detection of dna of agent of human granulocytic ehrlichiosis by pcr.ixodid ticks were collected from connecticut, massachusetts, missouri, pennsylvania, rhode island, and british columbia (canada) during 1991 to 1994 to determine the prevalence of infection with hemocytic (blood cell), rickettsia-like organisms. hemolymph obtained from these ticks was analyzed by direct and indirect fluorescent antibody (fa) staining methods with dog, horse, or human sera containing antibodies to ehrlichia canis, ehrlichia equi, or rickettsia rickettsii. of the 693 nymphal and a ...19958567911
temporal association of amblyomma americanum with the presence of ehrlichia chaffeensis reactive antibodies in white-tailed deer.from 1981 through 1993, tick infestations and serum antibodies reactive to ehrlichia chaffeensis, the causative agent of human ehrlichiosis, were monitored among white-tailed deer (odocoileus virginianus) at whitehall experimental forest, clarke county, georgia (usa). neither ticks nor e. chaffeensis antibodies were detected during the first two years of the study. infestations of the lone star tick (amblyomma americanum), a suspected vector of e. chaffeensis, first were noted on deer in 1983. p ...19958583627
prevalence of antibodies to coxiella burnetti, rickettsia conorii, and rickettsia typhi in seven african countries.the prevalences of antibodies reactive with coxiella burnetti, rickettsia conorii, and rickettsia typhi were determined by indirect fluorescent antibody testing of sera from seven african countries. the seroprevalences of antibodies reactive with c. burnetti and r. conorii in countries from north africa were similar to those reported from southern europe. in countries of sub-saharan africa, the seroprevalence of antibodies reactive with c. burnetti varied greatly; the generally higher figures fo ...19958589132
ixodid ticks from panthers and bobcats in florida.ixodid ticks were present in all 189 samples examined from 53 florida panthers (felis concolor coryi, 104 collections) and 85 bobcats (felis rufus floridana) in florida (usa) between 1974 and 1991. we identified 3,251 ticks from panthers and 918 from bobcats. specimens of dermacentor variabilis, ixodes scapularis, i. affinis, amblyomma maculatum, and a. americanum were present on 49, 39, 17, seven, and two of the 53 florida panthers, respectively, and comprised 36%, 55%, 7%, 1%, and < 1% of the ...19958592378
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 ...19958593414
parasites of domestic and wild animals in south africa. xxxiii. ixodid ticks on scrub hares in the north-eastern regions of northern and eastern transvaal and of kwazulu-natal.ixodid ticks were collected from scrub hares (lepus saxatilis) at three localities. nine tick species were recovered from 24 hares examined at pafuri, kruger national park, northern transvaal. the most abundant and prevalent species were hyalomma truncatum, rhipicephalus kochi and a rhipicephalus species (near r. pravus). twelve tick species were collected from 120 scrub hares examined around skukuza, kruger national park, eastern transvaal. the immature stages of hyalomma truncatum were most ab ...19958600436
parasites of domestic and wild animals in south africa. xxxiv. arthropod parasites of nyalas in north-eastern kwazulu-natal.seventy-three nyalas (tragelaphus angasii) in the umfolozi, mkuzi and ndumu game reserves in northeastern kwazulu-natal were examined for arthropod parasites during 1983 and 1984. in addition, six animals were examined during 1994. ten ixodid tick species, two louse species and a louse fly species were recovered. the nyalas were good hosts of all stages of development of boophilus decoloratus, rhipicephalus appendiculatus and rhipicephalus muehlensi and the immature stages of amblyomma hebraeum ...19958628570
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 ...19958847166
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 ...19968856759
survival and water-balance characteristics of unfed adult amblyomma cajennense (acari: ixodidae).off-host survival, water balance, and cold tolerance of unfed adult, cayenne ticks, amblyomma cajennense (f.), were examined to evaluate species characteristics important to zoogeography and off-host ecology. survivorship decreased when males and females were subjected to progressively drier constant environmental conditions. average maximum survival was 641.2 and 682.5 d at 85% rh and 23 degrees c (2.98 mm hg) for males and females, respectively. mean survival in both sexes was progressively le ...19968906907
ectoparasites (acari, mallophaga, anoplura, diptera) of white-tailed deer, odocoileus virginianus, from southern florida.during a 7-yr period (1984-1990), 300 white-tailed deer, odocoileus virginianus (zimmermann), from 7 localities in collier, dade, and monroe counties in southern florida were examined for ectoparasites. eight species were identified: 4 ticks [ixodes scapularis say, i. affinis neumann, amblyomma maculatum (koch), and dermacentor variabilis (say)], 1 chigger mite [eutrombicula splendens (ewing)], 1 ked (lipoptena mazamae rondani), 1 chewing louse [tricholipeurus lipeuroides (megnin)], and 1 suckin ...19968906911
seasonal activity and relative abundance of amblyomma americanum in mississippi.ecological investigations of the lone star tick, amblyomma americanum (l.), were conducted in 3 adjacent 60-m2 plots, located in noxubee national wildlife refuge, noxubee county, mississippi. ticks were collected weekly from july 1992 to july 1993 by flagging randomly selected lanes. during the year, larval ticks were collected first in early july, with peak numbers in september, and they were collected no later than late october. nymphal ticks were collected from mid-march to late october, with ...19968906916
site-specific geographic association between amblyomma americanum (acari: ixodidae) infestations and ehrlichia chaffeensis-reactive (rickettsiales: ehrlichieae) antibodies in white-tailed deer.serum samples from white-tailed deer, odocoileus virginianus zimmermann, collected from 1982 through 1992 from the southeastern united states were tested for antibodies reactive to ehrlichia chaffeensis anderson, dawson, jones, & wilson, the causative agent of human ehrlichiosis. results were compared between areas based on known infestations of the lone star tick, amblyomma americanum l., a suspected vector of e. chaffeensis. one hundred and twenty-five of 300 (41.7%) deer tested positive (> or ...19968906920
tick avoidance behaviors associated with a decreased risk of anti-tick salivary gland protein antibody seropositivity in military personnel exposed to amblyomma americanum in arkansas.during april through september 1990, 399 military personnel who originated from either fort chaffee, arkansas (n = 236) or fort wainwright, alaska (n = 163) were studied during maneuvers in tick-infested areas at fort chaffee. study subjects completed a questionnaire and had pre- and post-maneuvers serum specimens analyzed for antibodies to several rickettsial and ehrlichial agents and to amblyomma americanum (lone star tick) salivary gland proteins (anti-tick saliva antibodies [atsa], a biologi ...19968916798
human ehrlichiosis--maryland, 1994.ehrlichiosis is an emerging tickborne infectious disease caused by obligate intracellular, gram-negative rickettsia that infect leukocytes. human monocytic ehrlichiosis (hme) is caused by ehrlichia chaffeensis and is believed to be transmitted by amblyomma americanum (the lone star tick). most hme cases have been reported in southeastern and south-central states. during may-july 1994, five cases of serologically confirmed hme were identified among residents of maryland. all five persons lived ne ...19968926996
infestations of the bont tick amblyomma hebraeum (acari: ixodidae) on different breeds of cattle in zimbabwe.infestations of adults and nymphs of amblyomma hebraeum were counted on brahman (br), brahman x simmental (bs), sanga (sa) and hereford (he) steers exposed to infested pastures at mbizi in southern zimbabwe in 1986-1987. herefords were always the most heavily infested, while the sanga tended to carry the fewest ticks with the brahman and brahman x simmental groups being in between. the ratios of the engorged females on the four breeds were 2.3:1.4:1.4:1.0 for he:br:bs:sa. the ratios of the stand ...19968952073
proceedings of a workshop on the control of amblyomma variegatum and associated diseases. accra, ghana, 4 november 1994. 19968966770
impact on salivary gland degeneration by putative ecdysteroid antagonists and agonists in the ixodid tick amblyomma hebraeumecdysteroids cause salivary gland degeneration in female ixodid ticks. we tested the effects of the following compounds on salivary gland degeneration in the ixodid tick amblyomma hebraeum koch: hhcs (22s,23s-homocastasterone), ssbr (22s,23s-homobrassinolide), stgm (2alpha,3alpha(oh)2-delta22-stigmasten-6-one), rh 5849, and rh 5992. the first three are brassinosteroids (putative ecdysone antagonists) and the last two are nonsteroidal mimics of ecdysone in a variety of insects. in vitro, hhcs (up ...19968980038
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