| equine piroplasmosis associated with amblyomma cajennense ticks, texas, usa. | we report an outbreak of equine piroplasmosis in southern texas, usa, in 2009. infection prevalence reached 100% in some areas (292 infected horses). amblyomma cajennense was the predominant tick and experimentally transmitted theileria equi to an uninfected horse. we suggest that transmission by this tick species played a role in this outbreak. | 2011 | 22000367 |
| spotted fever group rickettsia infecting ticks (acari: ixodidae) in the state of santa catarina, brazil. | during 2006-2008, a total of 260 adult ticks were collected from domestic and wild animals in different regions of the state of santa catarina (sc), brazil, including areas where human cases of brazilian spotted fever have been reported. collected ticks belonging to nine species (amblyomma aureolatum, amblyomma cajennense, amblyomma dubitatum, amblyomma longirostre, amblyomma ovale, amblyomma tigrinum, dermacentor nitens, rhipicephalus microplus and rhipicephalus sanguineus) were tested by polym ... | 2011 | 22241112 |
| a prevalent alpha-proteobacterium paracoccus sp. in a population of the cayenne ticks (amblyomma cajennense) from rio de janeiro, brazil. | as rocky mountain spotted fever is the most common tick-borne disease in south america, the presence of rickettsia sp. in amblyomma ticks is a possible indication of its endemicity in certain geographic regions. in the present work, bacterial dna sequences related to rickettsia amblyommii genes in a. dubitatum ticks, collected in the brazilian state of mato grosso, were discovered. simultaneously, paracoccus sp. was detected in aproximately 77% of a. cajennense specimens collected in rio de jane ... | 2012 | 23271948 |
| rickettsial infection in ticks collected from road-killed wild animals in rio de janeiro, brazil. | during 2008-2010, ticks were collected from road-killed wild animals within the serra dos orgãos national park area in the state of rio de janeiro, brazil. in total, 193 tick specimens were collected, including amblyomma dubitatum neumann and amblyomma cajennense (f.) from four hydrochoerus hydrochaeris (l.), amblyomma calcaratum neumann and a. cajennense from four tamandua tetradactyla (l.), amblyomma aureolatum (pallas) and a. cajennense from five cerdocyon thous l., amblyomma longirostre (koc ... | 2012 | 23270184 |
| investigation of an outbreak of rickettsial febrile illness in guatemala, 2007. | we describe an outbreak of spotted fever group (sfg) rickettsiosis that occurred in 2007 in a farming community in southeastern guatemala. we identified 17 cases of an acute febrile illness, among which 10, including two fatalities, were confirmed or probable cases of rickettsial disease (case-fatality proportion 12%). | 2012 | 23266334 |
| meeting the challenges of on-host and off-host water balance in blood-feeding arthropods. | in this review, we describe water balance requirements of blood-feeding arthropods, particularly contrasting dehydration tolerance during the unfed, off-host state and the challenges of excess water that accompany receipt of the bloodmeal. most basic water balance characteristics during the off-host stage are applicable to other terrestrial arthropods, as well. a well-coordinated suite of responses enable arthropods to conserve water resources, enhance their desiccation tolerance, and increase t ... | 2010 | 20206630 |
| a multi-level analysis of the relationship between environmental factors and questing ixodes ricinus dynamics in belgium. | ticks are the most important pathogen vectors in europe. they are known to be influenced by environmental factors, but these links are usually studied at specific temporal or spatial scales. focusing on ixodes ricinus in belgium, we attempt to bridge the gap between current "single-sided" studies that focus on temporal or spatial variation only. here, spatial and temporal patterns of ticks are modelled together. | 2012 | 22830528 |
| composition and seasonal variation of rhipicephalus turanicus and rhipicephalus sanguineus bacterial communities. | a 16s rrna gene approach, including 454 pyrosequencing and quantitative pcr (qpcr), was used to describe the bacterial community in rhipicephalus turanicus and to evaluate the dynamics of key bacterial tenants of adult ticks during the active questing season. the bacterial community structure of rh. turanicus was characterized by high dominance of coxiella and rickettsia and extremely low taxonomic diversity. parallel diagnostic pcr further revealed a novel coxiella species which was present and ... | 2012 | 22467507 |
| species distribution models and ecological suitability analysis for potential tick vectors of lyme disease in mexico. | species distribution models were constructed for ten ixodes species and amblyomma cajennense for a region including mexico and texas. the model was based on a maximum entropy algorithm that used environmental layers to predict the relative probability of presence for each taxon. for mexico, species geographic ranges were predicted by restricting the models to cells which have a higher probability than the lowest probability of the cells in which a presence record was located. there was spatial n ... | 2012 | 22518171 |
| natural blood feeding and temperature shift modulate the global transcriptional profile of rickettsia rickettsii infecting its tick vector. | rickettsia rickettsii is an obligate intracellular tick-borne bacterium that causes rocky mountain spotted fever (rmsf), the most lethal spotted fever rickettsiosis. when an infected starving tick begins blood feeding from a vertebrate host, r. rickettsii is exposed to a temperature elevation and to components in the blood meal. these two environmental stimuli have been previously associated with the reactivation of rickettsial virulence in ticks, but the factors responsible for this phenotype c ... | 2013 | 24155949 |
| tick salivary compounds: their role in modulation of host defences and pathogen transmission. | ticks require blood meal to complete development and reproduction. multifunctional tick salivary glands play a pivotal role in tick feeding and transmission of pathogens. tick salivary molecules injected into the host modulate host defence responses to the benefit of the feeding ticks. to colonize tick organs, tick-borne microorganisms must overcome several barriers, i.e., tick gut membrane, tick immunity, and moulting. tick-borne pathogens co-evolved with their vectors and hosts and developed m ... | 2013 | 23971008 |
| pathogenic landscape of transboundary zoonotic diseases in the mexico-us border along the rio grande. | transboundary zoonotic diseases, several of which are vector borne, can maintain a dynamic focus and have pathogens circulating in geographic regions encircling multiple geopolitical boundaries. global change is intensifying transboundary problems, including the spatial variation of the risk and incidence of zoonotic diseases. the complexity of these challenges can be greater in areas where rivers delineate international boundaries and encompass transitions between ecozones. the rio grande serve ... | 2014 | 25453027 |
| population-based passive tick surveillance and detection of expanding foci of blacklegged ticks ixodes scapularis and the lyme disease agent borrelia burgdorferi in ontario, canada. | we identified ticks submitted by the public from 2008 through 2012 in ontario, canada, and tested blacklegged ticks ixodes scapularis for borrelia burgdorferi and anaplasma phagocytophilum. among the 18 species of ticks identified, i. scapularis, dermacentor variabilis, ixodes cookei and amblyomma americanum represented 98.1% of the 14,369 ticks submitted. rates of blacklegged tick submission per 100,000 population were highest in ontario's eastern region; d. variabilis in central west and easte ... | 2014 | 25171252 |
| population and demographic structure of ixodes scapularis say in the eastern united states. | the most significant vector of tick-borne pathogens in the united states is ixodes scapularis say (the blacklegged tick). previous studies have identified significant genetic, behavioral and morphological differences between northern vs. southern populations of this tick. because tick-borne pathogens are dependent on their vectors for transmission, a baseline understanding of the vector population structure is crucial to determining the risks and epidemiology of pathogen transmission. | 2014 | 25025532 |
| a 24-48 h fed amblyomma americanum tick saliva immuno-proteome. | multiple tick saliva proteins, the majority of which are unknown, confer tick resistance in repeatedly infested animals. the objective of this study was to identify the 24-48 h fed amblyomma americanum tick saliva immuno-proteome. the 24-48 h tick-feeding phase is critical to tick parasitism as it precedes important events in tick biology, blood meal feeding and disease agent transmission. fed male, 24 and 96 h fed female phage display cdna expression libraries were biopanned using rabbit antibo ... | 2014 | 24962723 |
| massive infection of seabird ticks with bacterial species related to coxiella burnetii. | seabird ticks are known reservoirs of bacterial pathogens of medical importance; however, ticks parasitizing tropical seabirds have received less attention than their counterparts from temperate and subpolar regions. recently, rickettsia africae was described to infect seabird ticks of the western indian ocean and new caledonia, constituting the only available data on bacterial pathogens associated with tropical seabird tick species. here, we combined a pyrosequencing-based approach with a class ... | 2014 | 24657860 |
| first record of borrelia burgdorferi b31 strain in dermacentor nitens ticks in the northern region of parana (brazil). | the aim of this study was to investigate the presence of dna of borrelia burgdorferi sensu lato (s.l.) in ticks that feed on horses used for animal traction in rural jataizinho, parana, brazil. between february and june 2008, a total of 224 ticks was collected of which 75% were identified as dermacentor nitens and 25% as amblyomma cajenense. to amplify b. burgdorferi s.l. dna, the intergenic space region (isr) between the 5s (rrf) 23s (rrl) rrna genes was used as targets for nested-pcr. two tick ... | 2014 | 24516456 |
| comparative population genetics of two invading ticks: evidence of the ecological mechanisms underlying tick range expansions. | two species of ixodid tick, ixodes affinis neumann and amblyomma maculatum koch, are simultaneously expanding their ranges throughout the mid-atlantic region of the us. although we have some understanding of the ecology and life history of these species, the ecological mechanisms governing where and how new populations establish and persist are unclear. to assess population connectivity and ancestry, we sequenced a fragment of the 16s mitochondrial rrna gene from a representative sample of indiv ... | 2015 | 26254575 |
| modulation of host immunity by tick saliva. | next generation sequencing and proteomics have helped to comprehensively characterize gene expression in tick salivary glands at both the transcriptome and the proteome level. functional data are, however, lacking. given that tick salivary secretions are critical to the success of the tick transmission lifecycle and, as a consequence, for host colonization by the pathogens they spread, we thoroughly review here the literature on the known interactions between tick saliva (or tick salivary gland ... | 2015 | 26189360 |
| borrelia burgdorferi sensu lato in humans in a rural area of paraná state, brazil. | this study describes the detection of borrelia garinii and borrelia burgdorferi sensu stricto (s.s.) in brazilian individuals using pcr and dna sequencing. our results suggest that these species are emerging pathogens in this country, and additional studies are necessary to determine the epidemiological characteristics of this disease in brazil. | 2015 | 26273276 |
| conserved amblyomma americanum tick serpin19, an inhibitor of blood clotting factors xa and xia, trypsin and plasmin, has anti-haemostatic functions. | tick saliva serine protease inhibitors (serpins) facilitate tick blood meal feeding through inhibition of protease mediators of host defense pathways. we previously identified a highly conserved amblyomma americanum serpin 19 that is characterised by its reactive center loop being 100% conserved in ixodid ticks. in this study, biochemical characterisation reveals that the ubiquitously transcribed a. americanum serpin 19 is an anti-coagulant protein, inhibiting the activity of five of the eight s ... | 2015 | 25957161 |
| passive surveillance for ticks on horses in saskatchewan. | passive surveillance of ticks on horses in saskatchewan revealed that the horses were parasitized by 3 species, dermacentor albipictus, d. andersoni, and d. variabilis. the nymphs and adults of d. albipictus occurred on horses earlier in the year than did adults of the 2 other species. | 2015 | 25969582 |
| vector potential and population dynamics for amblyomma inornatum. | we studied the natural life cycle of amblyomma inornatum and its vector potential in south texas. this tick is distributed throughout south texas and most of central america. a. inornatum represented 1.91% of the ticks collected by carbon dioxide traps during a study of free-living ticks in the tamaulipan biotic province in south texas. the life cycle of a. inornatum in south texas showed a clear seasonal pattern consistent with one generation per year. nymphs emerged in the spring with a peak i ... | 2015 | 25881916 |
| tick-borne infections in human and animal population worldwide. | the abundance and activity of ectoparasites and its hosts are affected by various abiotic factors, such as climate and other organisms (predators, pathogens and competitors) presenting thus multiples forms of association (obligate to facultative, permanent to intermittent and superficial to subcutaneous) developed during long co-evolving processes. ticks are ectoparasites widespread globally and its eco epidemiology are closely related to the environmental conditions. they are obligatory hematop ... | 2015 | 27047089 |
| potentially novel ehrlichia species in horses, nicaragua. | ehrlichia sp. dna was amplified from 4 ehrlichia-seroreactive horses from mérida, nicaragua. sequencing of 16s rdna, sodb, and groel genes indicated that the bacterium is most likely a novel ehrlichia species. the tick vector and the potential for canine and human infection remain unknown. | 2015 | 25625228 |
| coxiella detection in ticks from wildlife and livestock in malaysia. | recent studies have shown that ticks harbor coxiella-like bacteria, which are potentially tick-specific endosymbionts. we recently described the detection of coxiella-like bacteria and possibly coxiella burnetii in ticks found from rural areas in malaysia. in the present study, we collected ticks, including haemaphysalis bispinosa, haemaphysalis hystricis, dermacentor compactus, dermacentor steini, and amblyomma sp. from wildlife and domesticated goats from four different locations in malaysia. ... | 2016 | 27763821 |
| bacteria associated with amblyomma cajennense tick eggs. | ticks represent a large group of pathogen vectors that blood feed on a diversity of hosts. in the americas, the ixodidae ticks amblyomma cajennense are responsible for severe impact on livestock and public health. in the present work, we present the isolation and molecular identification of a group of culturable bacteria associated with a. cajennense eggs from females sampled in distinct geographical sites in southeastern brazil. additional comparative analysis of the culturable bacteria from an ... | 2015 | 26537602 |
| 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 |
| the case for a 'one health' approach to combating vector-borne diseases. | | 2015 | 26027713 |
| nhumirim virus, a novel flavivirus isolated from mosquitoes from the pantanal, brazil. | we describe the isolation of a novel flavivirus, isolated from a pool of mosquitoes identified as culex (culex) chidesteri collected in 2010 in the pantanal region of west-central brazil. the virus is herein designated nhumirim virus (nhuv) after the name of the ranch from which the mosquito pool was collected. flavivirus rna was detected by real-time rt-pcr of homogenized mosquitoes and from the corresponding c6/36 culture supernatant. based on full-genome sequencing, the virus isolate was gene ... | 2014 | 25252815 |
| characterisation of divergent flavivirus ns3 and ns5 protein sequences detected in rhipicephalus microplus ticks from brazil. | transcripts similar to those that encode the nonstructural (ns) proteins ns3 and ns5 from flaviviruses were found in a salivary gland (sg) complementary dna (cdna) library from the cattle tick rhipicephalus microplus. tick extracts were cultured with cells to enable the isolation of viruses capable of replicating in cultured invertebrate and vertebrate cells. deep sequencing of the viral rna isolated from culture supernatants provided the complete coding sequences for the ns3 and ns5 proteins an ... | 2013 | 24626302 |
| vaccination against bm86 homologues in rabbits does not impair ixodes ricinus feeding or oviposition. | human tick-borne diseases that are transmitted by ixodes ricinus, such as lyme borreliosis and tick borne encephalitis, are on the rise in europe. diminishing i. ricinus populations in nature can reduce tick exposure to humans, and one way to do so is by developing an anti-vector vaccine against tick antigens. currently, there is only one anti-vector vaccine available against ticks, which is a veterinary vaccine based on the tick antigen bm86 in the gut of rhipicephalus microplus. bm86 vaccine f ... | 2015 | 25919587 |
| amblyomma cajennense is an intrastadial biological vector of theileria equi. | the apicomplexan hemoprotozoan parasite theileria equi is one of the etiologic agents causing equine piroplasmosis, a disease of equines that is endemic throughout large parts of the world. before 2009 the united states had been considered to be free of this parasite. occasional cases had occurred but there was no evidence for endemic vector-borne transmission in the u.s. until a 2009 outbreak in texas in which dermacentor variabilis and amblyomma cajennense were implicated as vectors. although ... | 2013 | 24499587 |
| 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 |
| a new argasid tick species (acari: argasidae) associated with the rock cavy, kerodon rupestris wied-neuwied (rodentia: caviidae), in a semiarid region of brazil. | the rock cavy kerodon rupestris (wied-neuwied, 1820) is a rodent species endemic to northeastern brazil. earlier studies have associated the argasid tick ornithodoros talaje (guérin-méneville, 1849) with rocky cavy; however, a recent study proposed that o. talaje is not established in brazil, where previous reports of this species were possibly misidentifications of closely related species, yet to be properly determined. here, we describe a new species of ornithodoros koch, 1844 associated with ... | 2016 | 27655282 |
| heteroplasmy in the mitochondrial genomes of human lice and ticks revealed by high throughput sequencing. | the typical mitochondrial (mt) genomes of bilateral animals consist of 37 genes on a single circular chromosome. the mt genomes of the human body louse, pediculus humanus, and the human head louse, pediculus capitis, however, are extensively fragmented and contain 20 minichromosomes, with one to three genes on each minichromosome. heteroplasmy, i.e. nucleotide polymorphisms in the mt genome within individuals, has been shown to be significantly higher in the mt cox1 gene of human lice than in hu ... | 2013 | 24058467 |
| molecular epidemiology of the emerging zoonosis agent anaplasma phagocytophilum (foggie, 1949) in dogs and ixodid ticks in brazil. | anaplasma phagocytophilum is an emerging pathogen of humans, dogs and other animals, and it is transmitted by ixodid ticks. the objective of the current study was a) detect a. phagocytophilum in dogs and ixodid ticks using real-time polymerase chain reaction (qpcr); and b) determine important variables associated to host, environment and potential tick vectors that are related to the presence of a. phagocytophilum in dogs domiciled in rio de janeiro, brazil. | 2013 | 24330631 |
| challenges posed by tick-borne rickettsiae: eco-epidemiology and public health implications. | rickettsiae are obligately intracellular bacteria that are transmitted to vertebrates by a variety of arthropod vectors, primarily by fleas and ticks. once transmitted or experimentally inoculated into susceptible mammals, some rickettsiae may cause febrile illness of different morbidity and mortality, and which can manifest with different types of exhanthems in humans. however, most rickettsiae circulate in diverse sylvatic or peridomestic reservoirs without having obvious impacts on their vert ... | 2015 | 25954738 |
| rickettsia felis, an emerging flea-transmitted human pathogen. | rickettsia felis was first recognised two decades ago and has now been described as endemic to all continents except antarctica. the rickettsiosis caused by r. felis is known as flea-borne spotted fever or cat-flea typhus. the large number of arthropod species found to harbour r. felis and that may act as potential vectors support the view that it is a pan-global microbe. the main arthropod reservoir and vector is the cat flea, ctenocephalides felis, yet more than 20 other species of fleas, tick ... | 2011 | 24149035 |
| host specificity in a diverse neotropical tick community: an assessment using quantitative network analysis and host phylogeny. | host specificity is a fundamental determinant of tick population and pathogen transmission dynamics, and therefore has important implications for human health. tick host specificity is expected to be particularly high in the tropics, where communities of ticks, hosts and pathogens are most diverse. yet the degree to which tropical tick species are host-specific remains poorly understood. combining new field data with published records, we assessed the specificity of tick-host associations in pan ... | 2016 | 27357506 |
| geographical distribution of amblyomma cajennense (sensu lato) ticks (parasitiformes: ixodidae) in brazil, with description of the nymph of a. cajennense (sensu stricto). | until recently, amblyomma cajennense (fabricius, 1787) was considered to represent a single tick species in the new world. recent studies have split this taxon into six species. while the a. cajennense species complex or a. cajennense (sensu lato) (s.l.) is currently represented by two species in brazil, a. cajennense (sensu stricto) (s.s.) and amblyomma sculptum berlese, 1888, their geographical distribution is poorly known. | 2016 | 27036324 |
| ticks and rickettsiae from wildlife in belize, central america. | the agents of spotted fevers in latin america are rickettsia rickettsii, r. parkeri, rickettsia sp. strain atlantic rainforest, and r. massiliae. in continental central america, r. rickettsii remains the only known pathogenic tick-borne rickettsia. in the present study, ticks were collected from wild mammals in natural areas of belize. besides providing new data of ticks from belize, we investigated rickettsial infection in some of these ticks. our results provide ticks harboring rickettsial age ... | 2016 | 26831147 |
| epidemiological surveillance of capybaras and ticks on warning area for brazilian spotted fever. | the vulnerability of tropical developing countries to the emerging disease constitutes a critical phenomenon in which the invasion of wild niches by human hosts, contributes to expansion of zoonotic diseases, such as the brazilian spotted fever (bsf). this study performed a diagnosis of species occurrence of their hosts (hydrochoerus hydrochaeris) and vectors (amblyomma sculptum and amblyomma dubitatum) on the warning area for this reemerging disease in brazil. | 2015 | 27047211 |
| questing amblyomma mixtum and haemaphysalis juxtakochi (acari: ixodidae) infected with candidatus "rickettsia amblyommii" from the natural environment in panama canal basin, panama. | this work emphasizes the detection of candidatus "rickettsia amblyommii" in questing haemaphysalis juxtakochi and amblyomma mixtum. from february 2009 to december 2012, questing ticks were collected from the vegetation and leaf-litter of four protected forests and two grassy areas around the panama canal basin. dna was extracted from amblyomma mixtum, amblyomma naponense, amblyomma oblongoguttatum, amblyomma pecarium, amblyomma tapirellum, haemaphysalis juxtakochi, and unidentified immature ambl ... | 2015 | 26865823 |
| experimental infection of horses with rickettsia rickettsii. | rickettsia rickettsii is vectored by ticks, and some vertebrate hosts can be sources of infection to ticks during bacteremic periods. in brazil, the main vector for r. rickettsii is the tick amblyomma sculptum, a member of the a. cajennense complex. horses, in turn, are one of the major hosts for a. sculptum. in this study, horses experimentally infected with r. rickettsii were assessed for clinical changes and their capability to transmit the infection to a. sculptum ticks. | 2016 | 27624315 |
| brazilian spotted fever with an approach in veterinary medicine and one health perspective. | there is increasing interaction between man and pathogens transmitted by arthropods, especially by ticks. it is on this background that a holistic approach stands out, for the sake of public health. brazilian spotted fever is an endemic disease at the country's southeast, with amblyomma sculptum as its major contributor, followed by a. aureolatum and potentially rhipicephalus sanguineus. dogs have been considered sentinels, and in some areas the disease in dogs can precede human disease. conside ... | 2016 | 26881183 |
| rickettsia amblyommii infecting amblyomma sculptum in endemic spotted fever area from southeastern brazil. | the rickettsia bacteria include the aetiological agents for the human spotted fever (sf) disease. in the present study, a sf group rickettsia amblyommii related bacterium was detected in a field collected amblyomma sculptum (amblyomma cajennense species complex) tick from a brazilian sf endemic site in southeastern brazil, in the municipality of juiz de fora, state of minas gerais. genetic analysis based on genes ompa,ompb and htra showed that the detected strain, named r. amblyommii str. jf, is ... | 2015 | 26676317 |
| genetic identification of rickettsial isolates from fatal cases of brazilian spotted fever and comparison with rickettsia rickettsii isolates from the american continents. | fifteen bacterial isolates from spotted fever group rickettsiosis in brazil were genetically identified as rickettsia rickettsii. in a phylogenetic analysis with other r. rickettsii isolates from genbank, the central/south american isolates showed low polymorphism and formed a clade distinct from two north american clades, with the north american clades having greater in-branch polymorphism. | 2014 | 25078908 |
| rps8--a new informative dna marker for phylogeny of babesia and theileria parasites in china. | piroplasmosis is a serious debilitating and sometimes fatal disease. phylogenetic relationships within piroplasmida are complex and remain unclear. we compared the intron-exon structure and dna sequences of the rps8 gene from babesia and theileria spp. isolates in china. similar to 18s rdna, the 40s ribosomal protein s8 gene, rps8, including both coding and non-coding regions is a useful and novel genetic marker for defining species boundaries and for inferring phylogenies because it tends to ha ... | 2013 | 24244571 |
| risk factors for bartonella species infection in blood donors from southeast brazil. | bacteria from the genus bartonella are emerging blood-borne bacteria, capable of causing long-lasting infection in marine and terrestrial mammals, including humans. bartonella are generally well adapted to their main host, causing persistent infection without clinical manifestation. however, these organisms may cause severe disease in natural or accidental hosts. in humans, bartonella species have been detected from sick patients presented with diverse disease manifestations, including cat scrat ... | 2016 | 26999057 |
| satellite hyperspectral imagery to support tick-borne infectious diseases surveillance. | this study proposed the use of satellite hyperspectral imagery to support tick-borne infectious diseases surveillance based on monitoring the variation in amplifier hosts food sources. to verify this strategy, we used the data of the human rickettsiosis occurrences in southeastern brazil, region in which the emergence of this disease is associated with the rising capybara population. spatio-temporal analysis based on monte carlo simulations was used to identify risk areas of human rickettsiosis ... | 2015 | 26599337 |
| feeding period required by amblyomma aureolatum ticks for transmission of rickettsia rickettsii to vertebrate hosts. | rocky mountain spotted fever is endemic to the são paulo metropolitan area, brazil, where the etiologic agent, rickettsia rickettsii, is transmitted to humans by adult amblyomma aureolatum ticks. we determined the minimal feeding period required by a. aureolatum nymphs and adults to transmit r. rickettsii to guinea pigs. unfed nymphs and unfed adult ticks had to be attached to the host for >10 hours to transmit r. rickettsii. in contrast, fed ticks needed a minimum of 10 minutes of attachment to ... | 0 | 25148391 |
| rickettsia and vector biodiversity of spotted fever focus, atlantic rain forest biome, brazil. | | 0 | 24565262 |
| dogs, cats, parasites, and humans in brazil: opening the black box. | dogs and cats in brazil serve as primary hosts for a considerable number of parasites, which may affect their health and wellbeing. these may include endoparasites (e.g., protozoa, cestodes, trematodes, and nematodes) and ectoparasites (i.e., fleas, lice, mites, and ticks). while some dog and cat parasites are highly host-specific (e.g., aelurostrongylus abstrusus and felicola subrostratus for cats, and angiostrongylus vasorum and trichodectes canis for dogs), others may easily switch to other h ... | 2014 | 24423244 |
| rickettsial infection in amblyomma cajennense ticks and capybaras (hydrochoerus hydrochaeris) in a brazilian spotted fever-endemic area. | brazilian spotted fever (bsf), caused by the bacterium rickettsia rickettsii, is the deadliest spotted fever of the world. in most of the bsf-endemic areas, capybaras (hydrochoerus hydrochaeris) are the principal host for the tick amblyomma cajennense, which is the main vector of bsf. | 2014 | 24387674 |
| ecology, biology and distribution of spotted-fever tick vectors in brazil. | spotted-fever-caused rickettsia rickettsii infection is in brazil the major tick-borne zoonotic disease. recently, a second and milder human rickettsiosis caused by an agent genetically related to r. parkeri was discovered in the country (atlantic rainforest strain). both diseases clearly have an ecological background linked to a few tick species and their environment. capybaras (hydrochoerus hydrochaeris) and amblyomma cajennense ticks in urban and rural areas close to water sources are the mai ... | 2013 | 23875178 |
| molecular ecological insights into neotropical bird-tick interactions. | in the tropics, ticks parasitize many classes of vertebrate hosts. however, because many tropical tick species are only identifiable in the adult stage, and these adults usually parasitize mammals, most attention on the ecology of tick-host interactions has focused on mammalian hosts. in contrast, immature neotropical ticks are often found on wild birds, yet difficulties in identifying immatures hinder studies of birds' role in tropical tick ecology and tick-borne disease transmission. in panama ... | 2016 | 27203693 |
| contributions to rickettsioses research in colombia (1917-1943), luis b. patiño camargo. | colombian physician luis benigno patiño camargo was one of the pioneers in the study of rickettsioses in south america, demonstrating for the first time in colombia the presence of rickettsia rickettsii as the etiological agent of a highly deadly exanthematic febrile syndrome in the 1930s. however, patiño-camargo performed other investigations from 1917-1943, which represent the first descriptions and scientific evidence of the presence of r. prowazekii and r. typhi in colombia. almost 60 years ... | 2016 | 27074327 |
| serological survey of ehrlichia species in dogs, horses and humans: zoonotic scenery in a rural settlement from southern brazil. | the aims of this study were to determine the seroprevalence of ehrlichia spp. and risk factors for exposure in a restricted population of dogs, horses, and humans highly exposed to tick bites in a brazilian rural settlement using a commercial elisa rapid test and two indirect immunofluorescent assays (ifa) with e. canis and e. chaffeensis crude antigens. serum samples from 132 dogs, 16 horses and 100 humans were used. fifty-six out of 132 (42.4%) dogs were seropositive for e. canis. dogs > one y ... | 0 | 24037288 |
| understanding the evolutionary structural variability and target specificity of tick salivary kunitz peptides using next generation transcriptome data. | ticks are blood-sucking arthropods and a primary function of tick salivary proteins is to counteract the host's immune response. tick salivary kunitz-domain proteins perform multiple functions within the feeding lesion and have been classified as venoms; thereby, constituting them as one of the important elements in the arms race with the host. the two main mechanisms advocated to explain the functional heterogeneity of tick salivary kunitz-domain proteins are gene sharing and gene duplication. ... | 2014 | 24397261 |
| tick-borne rickettsial pathogens in questing ticks, removed from humans and animals in mexico. | tick-borne rickettsial diseases (tbrd) are commonly encountered in medical and veterinary clinical settings. the control of these diseases is difficult, requiring disruption of a complex transmission chain involving a vertebrate host and ticks. the geographical distribution of the diseases is related to distribution of the vector, which is an indicator of risk for the population. a total of 1107 were collected by tick drag from forests, ecotourism parks and hosts at 101 sites in 22 of the 32 sta ... | 0 | 26726019 |
| tick-induced allergies: mammalian meat allergy, tick anaphylaxis and their significance. | serious tick-induced allergies comprise mammalian meat allergy following tick bites and tick anaphylaxis. mammalian meat allergy is an emergent allergy, increasingly prevalent in tick-endemic areas of australia and the united states, occurring worldwide where ticks are endemic. sensitisation to galactose-α-1,3-galactose (α-gal) has been shown to be the mechanism of allergic reaction in mammalian meat allergy following tick bite. whilst other carbohydrate allergens have been identified, this alle ... | 2015 | 25653915 |
| the sialotranscriptome of amblyomma triste, amblyomma parvum and amblyomma cajennense ticks, uncovered by 454-based rna-seq. | tick salivary constituents antagonize inflammatory, immune and hemostatic host responses, favoring tick blood feeding and the establishment of tick-borne pathogens in hosts during hematophagy. amblyomma triste, a. cajennense and a. parvum ticks are very important in veterinary and human health because they are vectors of the etiological agents for several diseases. insights into the tick salivary components involved in blood feeding are essential to understanding vector-pathogen-host interaction ... | 2014 | 25201527 |
| candidatus rickettsia andeanae, a spotted fever group agent infecting amblyomma parvum ticks in two brazilian biomes. | adult ticks of the species amblyomma parvum were collected from the vegetation in the pantanal biome (state of mato grosso do sul) and from horses in the cerrado biome (state of piauí) in brazil. the ticks were individually tested for rickettsial infection via polymerase chain reaction (pcr) targeting three rickettsial genes, glta, ompa and ompb. overall, 63.5% (40/63) and 66.7% (2/3) of a. parvum ticks from pantanal and cerrado, respectively, contained rickettsial dna, which were all confirmed ... | 0 | 24714968 |
| host-parasite relationship of ticks (acari: ixodidae and argasidae) and feral pigs (sus scrofa) in the nhecolândia region of the pantanal wetlands in mato grosso do sul. | feral pigs (s. scrofa) were introduced to the pantanal region around 200 years ago and the population appears to be in expansion. its eradication is considered to be impossible. the population of feral pigs in the pantanal wetlands is currently estimated at one million. two scientific excursions were organized. the first was conducted during the dry season, when 21 feral pigs were captured and the second was during the wet season, when 23 feral pigs were captured. ticks were collected and the ov ... | 2013 | 27335855 |
| amblyomma tapirellum (acari: ixodidae) collected from tropical forest canopy. | free-ranging ticks are widely known to be restricted to the ground level of vegetation. here, we document the capture of the tick species amblyomma tapirellum in light traps placed in the forest canopy of barro colorado island, central panama. a total of forty eight adults and three nymphs were removed from carbon dioxide-octenol baited cdc light traps suspended 20 meters above the ground during surveys for forest canopy mosquitoes. to our knowledge, this represents the first report of questing ... | 2013 | 25075277 |
| histoarchitecture of the ovary of rhipicephalus (boophilus) annulatus during pre- and postengorgement period. | the present communication describes the detailed day wise study of histological changes of the ovary of rhipicephalus (boophilus) annulatus in the postengorgement period together with the systematic classification of their oocytes. the ovary of r. (b.) annulatus is panoistic type with an asynchronous development of oocytes. all the stages (ii, iii, iv, and v) of oocytes except stage i were similar to r. (b.) microplus. the stage i oocytes showed basophilia, which was not reported earlier in othe ... | 2015 | 25664337 |
| molecular identification of rickettsia parkeri infecting amblyomma triste ticks in an area of argentina where cases of rickettsiosis were diagnosed. | specimens of the hard tick amblyomma triste were found infected with rickettsia parkeri in an area of argentina (general lavalle, buenos aires province) where cases of human illness attributed to this microorganism have been reported. molecular detection of r. parkeri was based on polymerase chain reactions that amplify a ca. 400-bp fragment of the 23s-5s intergenic spacer and a ca. 500-bp fragment of the gene encoding a 190-kda outer membrane protein. three (6.97%) of 43 a. triste ticks were de ... | 0 | 23440128 |
| rickettsia bellii, rickettsia amblyommii, and laguna negra hantavirus in an indian reserve in the brazilian amazon. | the purpose of this study was to identify the presence of rickettsia and hantavirus in wild rodents and arthropods in response to an outbreak of acute unidentified febrile illness among indians in the halataikwa indian reserve, northwest of the mato grosso state, in the brazilian amazon. where previously surveillance data showed serologic evidence of rickettsia and hantavirus human infection. | 2014 | 24742108 |
| native strains of beauveria bassiana for the control of rhipicephalus sanguineus sensu lato. | rhipicephalus sanguineus sensu lato ticks are widespread worldwide due to their adaptability to survive under different environmental conditions. they may act as vectors of a wide range of pathogens to humans and animals and their control is based on the use of chemical products on dogs and in the environment. alternative control strategies, such as the use of entomopathogenic fungi as bio-control agents have also been investigated. the ability of native strains of beauveria bassiana sensu lato ... | 2015 | 25651851 |
| sensitivity to permethrin in a dermacentor reticulatus population from eastern poland in laboratory study. | the action of chemical compounds on the palaearctic tick d. reticulatus (fabricius) (acari: amblyomminae) has been poorly investigated so far. therefore, the effects of application of permethrin on engorged d. reticulatus females have been assessed, and the survival rate for the different developmental stages of the tick species in its non-parasitic phase of the life cycle was determined upon application of the pyrethroid. | 2014 | 24405550 |
| arachnids of medical importance in brazil: main active compounds present in scorpion and spider venoms and tick saliva. | arachnida is the largest class among the arthropods, constituting over 60,000 described species (spiders, mites, ticks, scorpions, palpigrades, pseudoscorpions, solpugids and harvestmen). many accidents are caused by arachnids, especially spiders and scorpions, while some diseases can be transmitted by mites and ticks. these animals are widely dispersed in urban centers due to the large availability of shelter and food, increasing the incidence of accidents. several protein and non-protein compo ... | 2015 | 26273285 |
| effect of the saliva from different triatomine species on the biology and immunity of tlr-4 ligand and trypanosoma cruzi-stimulated dendritic cells. | triatomines are blood-sucking vectors of trypanosoma cruzi, the causative agent of chagas disease. during feeding, triatomines surpass the skin host response through biomolecules present in their saliva. dendritic cells (dcs) play a crucial role in the induction of the protection to aggressive agents, including blood-sucking arthropods. here, we evaluated if salivary components of triatomines from different genera evade the host immunity by modulating the biology and the function of lps- or t. c ... | 2016 | 27938380 |
| the genome of the crustacean parhyale hawaiensis, a model for animal development, regeneration, immunity and lignocellulose digestion. | the amphipod crustacean parhyale hawaiensis is a blossoming model system for studies of developmental mechanisms and more recently regeneration. we have sequenced the genome allowing annotation of all key signaling pathways, transcription factors, and non-coding rnas that will enhance ongoing functional studies. parhyale is a member of the malacostraca clade, which includes crustacean food crop species. we analysed the immunity related genes of parhyale as an important comparative system for the ... | 2016 | 27849518 |
| a review of piroplasmid infections in wild carnivores worldwide: importance for domestic animal health and wildlife conservation. | piroplasmids are tick-borne protozoan parasites that infect blood cells (erythrocytes, lymphocytes or other leukocytes) or endothelial cells of numerous wild and domestic vertebrates worldwide. they cause severe disease in livestock, dogs, cats, wild mammals and, occasionally, in humans. piroplasmid infections are prevalent in wild carnivores worldwide although there is limited information about their clinical and epidemiological importance. there are currently nine recognized species of babesia ... | 2016 | 27724937 |
| acute oral mammalian toxicity and effect of solvents on efficacy of maerua edulis (gilg. & ben.) de wolf against rhipicephalus (boophilus) decoloratus koch, 1844 (acarina: ixodidae), tick larvae. | efficacy and toxicity of aqueous and organic solvents extracts of maerua edulis against ticks and mice, respectively, were determined. ground leaves were extracted separately using cold water, cold water plus surfactant (1% v/v liquid soap), hot water plus surfactant, hexane, or methanol to make 25% w/v stock solutions from which serial dilutions of 5, 10, 20, and 25% were made. for each concentration, 20 rhipicephalus decoloratus tick larvae were put in filter papers impregnated with extracts a ... | 2016 | 27660762 |
| an update on the epidemiological situation of spotted fever in brazil. | spotted fever is a tick-borne rickettsial disease. in brazil, its notification to the ministry of health is compulsory. since 2007, cases of spotted fever have been integrated to the notifiable diseases information system, and epidemiological analyzes are part of the routines on surveillance programs. | 2016 | 27555867 |
| saliva of rhipicephalus (boophilus) microplus (acari: ixodidae) inhibits classical and alternative complement pathways. | rhipicephalus (boophilus) microplus is the main ectoparasite affecting livestock worldwide. for a successful parasitism, ticks need to evade several immune responses of their hosts, including the activation of the complement system. in spite of the importance of r. microplus, previous work only identified one salivary molecule that blocks the complement system. the current study describes complement inhibitory activities induced by r. microplus salivary components and mechanisms elicited by puta ... | 2016 | 27515662 |
| rickettsia detected in the reptile tick bothriocroton hydrosauri from the lizard tiliqua rugosa in south australia. | rickettsiosis is a potentially fatal tick borne disease. it is caused by the obligate intracellular bacteria rickettsia, which is transferred to humans through salivary excretions of ticks during the biting process. globally, the incidence of tick-borne diseases is increasing; as such, there is a need for a greater understanding of tick-host interactions to create more informed risk management strategies. flinders island spotted fever rickettsioses has been identified throughout australia (tasma ... | 2016 | 27338482 |
| molecular identification of anaplasma marginale in two autochthonous south american wild species revealed an identical new genotype and its phylogenetic relationship with those of bovines. | anaplasma marginale is a well-known cattle pathogen of tropical and subtropical world regions. even though, this obligate intracellular bacterium has been reported in other host species different than bovine, it has never been documented in myrmecophaga tridactyla (giant anteater) or hippocamelus antisense (taruca), which are two native endangered species. | 2016 | 27229471 |
| amblyomin-x induces er stress, mitochondrial dysfunction, and caspase activation in human melanoma and pancreatic tumor cell. | during the last two decades, new insights into proteasome function and its role in several human diseases made it a potential therapeutic target. in this context, amblyomin-x is a kunitz-type fxa inhibitor similar to endogenous tissue factor pathway inhibitor (tfpi) and is a novel proteasome inhibitor. herein, we have demonstrated amblyomin-x cytotoxicity to different tumor cells lines such as pancreatic (panc1, aspc1bxpc3) and melanoma (sk-mel-5 and sk-mel-28). of note, amblyomin-x was not cyto ... | 2016 | 27015684 |
| frequency and distribution of rickettsiae, borreliae, and ehrlichiae detected in human-parasitizing ticks, texas, usa. | to describe the presence and distribution of tickborne bacteria and their vectors in texas, usa, we screened ticks collected from humans during 2008-2014 for rickettsia, borrelia, and ehrlichia spp. thirteen tick species were identified, and 23% of ticks carried bacterial dna from at least 1 of the 3 genera tested. | 0 | 26811941 |
| molecular detection of theileria spp. in livestock on five caribbean islands. | theileria spp. are tick-transmitted, intracellular apicomplexan protozoan parasites infecting a wide range of animals. as there is very limited information on the prevalence of theileria spp. in the caribbean we used the recently described genus-specific pan-theileria fret-qpcr to identify infected animals in the region and a standard 18s rrna gene pcr and sequencing to determine the species involved. we found theileria spp. in 9% of the convenience samples of animals (n = 752) studied from five ... | 2015 | 26783522 |
| molecular methods routinely used to detect coxiella burnetii in ticks cross-react with coxiella-like bacteria. | q fever is a widespread zoonotic disease caused by coxiella burnetii. ticks may act as vectors, and many epidemiological studies aim to assess c. burnetii prevalence in ticks. because ticks may also be infected with coxiella-like bacteria, screening tools that differentiate between c. burnetii and coxiella-like bacteria are essential. | 2015 | 26609691 |
| brazilian spotted fever: the importance of dermatological signs for early diagnosis. | brazilian spotted fever is an acute febrile infectious disease caused by rickettsia rickettsii, transmitted by tick bite. as this disease is rare and has high mortality rates in brazil, the clinical aspects and epidemiological data may help the diagnosis. we report a case of brazilian spotted fever in a 19-year-old patient who presented maculopapular exanthema in the palmar region and upper limbs, lymphadenopathy, fever, chills, headache, conjunctival hyperemia, nausea, vomiting, dyspnea, myalgi ... | 0 | 25830998 |
| rickettsia rickettsii in amblyomma patinoi ticks, colombia. | | 0 | 25695155 |
| comparative genome sequencing of rickettsia rickettsii strains that differ in virulence. | rickettsia rickettsii is an obligate intracellular pathogen that is the causative agent of rocky mountain spotted fever. strains of r. rickettsii differ dramatically in virulence. in a guinea pig model of infection, the severity of disease as assessed by fever response varies from the most virulent, sheila smith, to iowa, which causes no fever. to identify potential determinants of virulence in r. rickettsii, the genomes of two additional strains were sequenced for comparison to known sequences ... | 2015 | 25644009 |
| immunosuppressive effects of amblyomma cajennense tick saliva on murine bone marrow-derived dendritic cells. | dendritic cells (dcs) are professional antigen-presenting cells with vital roles in the activation of host immunity. ticks are bloodsucking arthropods that secrete bioactive compounds with immunomodulatory properties via their saliva. it is known that some tick species modulate the biology of dcs with different intensities; however, studies on amblyomma cajennense, the cayenne tick, have not yet been performed, although this species is considered one of the most capable of modulating immune resp ... | 2015 | 25586117 |
| dynein function and protein clearance changes in tumor cells induced by a kunitz-type molecule, amblyomin-x. | amblyomin-x is a kunitz-type recombinant protein identified from the transcriptome of the salivary glands of the tick amblyomma cajennense and has anti-coagulant and antitumoral activity. the supposed primary target of this molecule is the proteasome system. herein, we elucidated intracellular events that are triggered by amblyomin-x treatment in an attempt to provide new insight into how this serine protease inhibitor, acting on the proteasome, could be comparable with known proteasome inhibito ... | 2014 | 25479096 |
| amblyomma cajennense (fabricius, 1787) (acari: ixodidae), the cayenne tick: phylogeography and evidence for allopatric speciation. | amblyomma cajennense f. is one of the best known and studied ticks in the new world because of its very wide distribution, its economical importance as pest of domestic ungulates, and its association with a variety of animal and human pathogens. recent observations, however, have challenged the taxonomic status of this tick and indicated that intraspecific cryptic speciation might be occurring. in the present study, we investigate the evolutionary and demographic history of this tick and examine ... | 2013 | 24320199 |
| chemical composition and insecticidal activity of plant essential oils from benin against anopheles gambiae (giles). | insecticide resistance in sub-saharan africa and especially in benin is a major public health issue hindering the control of the malaria vectors. each anopheles species has developed a resistance to one or several classes of the insecticides currently in use in the field. therefore, it is urgent to find alternative compounds to conquer the vector. in this study, the efficacies of essential oils of nine plant species, which are traditionally used to avoid mosquito bites in benin, were investigate ... | 2013 | 24298981 |
| tick-borne lymphadenopathy-like condition in an african woman in kenya. | a 30-year-old african woman in kenya succumbed to severe swollen regional lymph nodes, development of painful boils and ulcer formation and rashes at specific tick-biting sites together with an intermittent fever and headache following repeated tick bites of rhipicephalus pulchellus. she later developed nuchal lymphadenopathy-like condition and an eschar with edematous margins at bitten sites. a sustained high fever and fatigue then followed. she became well after treatment with antibiotics and ... | 0 | 24497868 |
| molecular epidemiology of theileria equi in horses and their association with possible tick vectors in the state of rio de janeiro, brazil. | the aim of this study was to detect theileria equi (laveran 1901) dna in horses and ticks using real-time pcr and to list the factors associated with infection in animals located in the seropedica and petropolis municipalities of the state of rio de janeiro. we tested blood samples from 314 horses and samples from 300 ticks, including 191 amblyomma cajennense, 104 dermacentor nitens, and 5 ixodida larvae. factors inherent to the horse, the ownership, and animal management were obtained from an e ... | 2013 | 23474658 |
| genetic characterization of theileria equi infecting horses in north america: evidence for a limited source of u.s. introductions. | theileria equi is a tick-borne apicomplexan hemoparasite that causes equine piroplasmosis. this parasite has a worldwide distribution but the united states was considered to be free of this disease until recently. | 2013 | 23399005 |
| comparative genomic analysis and phylogenetic position of theileria equi. | transmission of arthropod-borne apicomplexan parasites that cause disease and result in death or persistent infection represents a major challenge to global human and animal health. first described in 1901 as piroplasma equi, this re-emergent apicomplexan parasite was renamed babesia equi and subsequently theileria equi, reflecting an uncertain taxonomy. understanding mechanisms by which apicomplexan parasites evade immune or chemotherapeutic elimination is required for development of effective ... | 2012 | 23137308 |
| a novel proteasome inhibitor acting in mitochondrial dysfunction, er stress and ros production. | in cancer-treatment, potentially therapeutic drugs trigger their effects through apoptotic mechanisms. generally, cell response is manifested by bcl-2 family protein regulation, the impairment of mitochondrial functions, and ros production. notwithstanding, several drugs operate through proteasome inhibition, which, by inducing the accumulation and aggregation of misfolded or unfolded proteins, can lead to endoplasmic reticulum (er) stress. accordingly, it was shown that amblyomin-x, a kunitz-ty ... | 2012 | 22975862 |
| re-emergence of the apicomplexan theileria equi in the united states: elimination of persistent infection and transmission risk. | arthropod-borne apicomplexan pathogens that cause asymptomatic persistent infections present a significant challenge due to their life-long transmission potential. although anti-microbials have been used to ameliorate acute disease in animals and humans, chemotherapeutic efficacy for apicomplexan pathogen elimination from a persistently infected host and removal of transmission risk is largely unconfirmed. the recent re-emergence of the apicomplexan theileria equi in u.s. horses prompted testing ... | 2012 | 22970295 |
| phylogeography and demographic history of amblyomma variegatum (fabricius) (acari: ixodidae), the tropical bont tick. | the genetic diversity of amblyomma variegatum (fabricius) from four caribbean islands and five african countries was compared by analyzing the sequences of three gene fragments, two mitochondrial (12srdna and d-loop-dl), and one nuclear (intergenic transcribed spacer 2 [its2]). genetic variability of the its2 dna fragment consisted of only uninformative single nucleotide mutations, and therefore this gene was excluded from further analyses. mitochondrial gene divergences among african population ... | 2012 | 22448720 |
| antiviral effect of the egg wax of amblyomma cajennense (acari: ixodidae). | the control of viral infections, especially those caused by influenza viruses, is of great interest in public health. bio prospection has shown the presence of active principles in the hemolymph of arthropods, and in the salivary gland of ticks, and some of these are of interest for the development of new pharmacological drugs. ticks lay their eggs in the environment, and to protect them from desiccation and microbial attack they involve the eggs in a waxy layer produced by an organ known as gen ... | 2012 | 22441939 |
| the environmental-endocrine basis of gynandromorphism (intersex) in a crustacean. | commensurate with the decline in many crustacean populations has been an accumulation in reports of sexually ambiguous individuals within these populations. the cause of gynandromorphism or intersex among crustaceans is unknown. we show that gynandromorphism in the branchiopod crustacean daphnia magna is initiated by the sex-determining hormone methyl farnesoate when levels of the hormone are intermediate between low levels that stimulate the production of broods containing all female offspring ... | 2006 | 17205107 |