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At least 19 recordsLinked to original sources
PubMed1985

Ornithodoros (Alectorobius) spheniscus n. sp. [Acarina: Ixodoidea: Argasidae: Ornithodoros (Alectorobius) capensis group], a tick parasite of the Humboldt penguin in Peru.

Ornithodoros (Alectorobius) spheniscus n. sp., described from wild-caught and laboratory-reared females, males, nymphs, and larvae parasitizing the Humboldt Penguin, Spheniscus humboldti Meyen, is the fifth species of the Ornithodoros (Alectorobius) capensis group to be recognized in the Neotropical Region. A related Peruvian species, Ornithodoros (Alectorobius) amblus Chamberlin, also parasitizes S. humboldti but is recorded from a wider range of marine birds breeding on the Pacific coast and offshore islands, where the birds congregate to feed on the rich fish fauna usually produced by the Humboldt current. Differential criteria are provided for the new species, O. (A.) amblus, and Ornithodoros (Alectorobius) yunkeri Keirans, Clifford, and Hoogstraal of the Galapagos. These 3 members of the O. (A.) capensis group parasitize marine birds associated with the Humboldt current in western South America and the Galapagos. Persons visiting Humboldt Penguin breeding sites in caves and on barren coastal ledges are eagerly attacked by nymphal and adult O. (A.) spheniscus and suffer afterward from pruritus and slowly-healing blisters. The O. (A.) spheniscus life cycle required 128 to 193 days in the laboratory and, as typical of bird-parasitizing members of the subgenus Alectorobius, the first nymphal instar did not feed.

Animals↗
PubMed1995

A study of the vaccinal value of various extracts of concealed antigens and salivary gland extracts against Ornithodoros erraticus and Ornithodoros moubata.

On pig farms, elimination of the argasid ticks acting as reservoirs and vectors for African swine fever greatly favours the eradication of this disease. The elimination of Ornithodoros erraticus involves many problems, most of which could be easily solved by the development of an anti-O. erraticus vaccine. With a view to developing this vaccine, we have tested the protective value of the immune response induced in swine by seven 'concealed' antigens and one soluble salivary gland extract. The latter extract was also prepared from Ornithodoros moubata specimens and tested against this tick. Our results indicate that the immune response elicited by the concealed antigens has no protective value against O. erraticus. The immune response induced by the salivary gland extracts against adults of O. erraticus and O. moubata was apparent in a reduced ingestion of blood (40-60%; P < 0.01) (except in males of O. erraticus) and in a significant decrease (40-60%; P < 0.01) in fecundity in 100% of the females of both species. The good results obtained with salivary antigens, which in situations of natural contact have no protective value, are attributed to the fact that when these antigens are injected with adjuvants, the immune system recognizes certain salivary components (probably those which enable the parasite to feed) which it does not recognize under natural conditions of exposure.

African Swine Fever↗
PubMed1994

Biochemical changes in the coxal organ proper and accessory glands of female Ornithodoros (Ornithodoros) savignyi at different physiological conditions.

Changes in the total protein, DNA, RNA, lipid and phospholipid concentrations in the coxal organ proper and accessory glands of Ornithodoros (Ornithodoros) savignyi (Audouin) were studied. There was an increase in the total protein, DNA, RNA, lipid and phospholipid content of the coxal organ proper in the female upto 6-days after feeding, then the concentration decreased. Also, the content of protein, DNA, RNA, lipid and phospholipid in the coxal organ proper of the seventh nymphal instar were similar to unfed females. Accessory glands showed an increase in protein, DNA, RNA, lipid and phospholipid content that reached its maximum on day 8 after feeding in females, then decreased.

Animals↗
PubMed1997

Antigens of interest for the diagnosis of parasitism in pigs by Ornithodoros erraticus and Ornithodoros moubata.

We show by sodium dodecyl sulfate polyacrylamide gel electrophoresis and western blot that the composition of the soluble extracts of salivary glands (SGE-2) of Ornithodoros erraticus and Ornithodoros moubata is similar to that of the saliva (pilocarpine-induced), and that the extracts are a valid source of antigens for the detection of anti-argasid antibodies. It is also shown that the SGE-2s do not vary qualitatively with the developmental stage, physiological status, or sex of the ticks. The antigenic components (at least in O. erraticus) are released into the SGE-2 by the action of enzymes that can be inhibited by phenylmethane sulfonyl fluoride plus EDTA. Most of the components of the SGE-2, except the antigenic ones, are strongly glycosylated. Accordingly, the deglycosylation of the SGE-2s does not affect the recognition of antigenic components by anti-tick sera. In both species, the major components of the SGE-2s or the saliva are not recognized by the corresponding antisera. These nonimmunogenic components could have vaccinal value but not diagnostic interest. Finally, it is shown that the antigens of O. erraticus and O. moubata do not cross-react with one another and that those of the first species are more antigenic than those of the second.

Animals↗
PubMed2000

First record of natural infection with Borrelia in ornithodoros (Ornithodoros) savignyi. Reservoir potential and specificity of the tick to Borrelia.

Field and laboratory data provided convincing evidence implicating O. savignyi at Shelateen, Halayeb province as a reservoir and a vector of a specific Borrelia. Using direct immunofluorescence Borrelia infection was detected for the first time in a natural population of O. savignyi in Egypt. The overall infection rate (IR) was relatively high (50.63%) and the infected ticks were capable of transmitting the infection to hamsters during feeding. Infected nymphs maintained borrelial infection transstadially to adults and the transstadially infected stages transmitted the spirochetes to hamsters. However, directly infected females were more efficient than males in transmitting the spirochetes to hamster and the IR of hamsters increased gradually by increasing the number of feeding infected ticks upon each hamster. Transovarial transmission of Borrelia intrinsic to O. savignyi occurred during the first and second gonadotrophic cycle of the infected females. The Borrelia sp. detected in the field collected O. savignyi showed specificity for its own natural tick host species when compared with B. crocidurae isolated from O. erraticus. Although the two tick species acquired, transstadially transferred and transmitted the two spirochetal infections, each tick species failed to transovarially transmit Borrelia isolated from the natural population of the other tick species.

Animals↗
PubMed2004

Experimental transmission of Karshi and Langat (tick-borne encephalitis virus complex) viruses by Ornithodoros ticks (Acari: Argasidae).

Selected species of mosquitoes and Ornithodoros ticks were evaluated for their potential to transmit Karshi and Langat (tick-borne encephalitis virus complex) viruses in the laboratory. Although there was no evidence of replication of Karshi virus in either of the two mosquito species tested [Ochlerotatus taeniorhynchus (Wiedemann) or Culex pipiens (L.)], Karshi virus replicated in and was transmitted by all three species of Ornithodoros ticks tested (Ornithodoros parkeri Cooley, Ornithodoros sonrai Sautet & Witkowski, and Ornithodoros tartakovskyi Olenev). When inoculated with Karshi virus, 90% of Ornithodoros ticks (44/49) transmitted this virus by bite to suckling mice, and transmission continued to occur for at least 1 yr, the longest extrinsic incubation tested. After feeding on a suckling mouse with a viremia of approximately 10(5) suckling mouse subcutaneous lethal dose. units of Karshi virus per milliliter of blood, all three species of Ornithodoros tested became infected with and transmitted Karshi virus both trans-stadially and horizontally by bite to suckling mice. In addition, female O. tartakovskyi transmitted Karshi virus vertically to their progeny. In a continuation of a previous study, O. sonrai, orally exposed to Langat virus, were able to transmit this virus after >3 yr, the longest interval tested. Therefore, Ornithodoros spp. should be considered as potential vectors and as possible long-term maintenance hosts for Karshi virus and other members of the tick-borne encephalitis virus complex.

Animals↗
PubMed2002

Antibacterial peptide defensin is involved in midgut immunity of the soft tick, Ornithodoros moubata.

Two defensin genes A and B were previously demonstrated to be up-regulated by blood feeding in the soft tick, Ornithodoros moubata [Nakajima et al. (2001) Two isoforms of a member of the arthropod defensin family from the soft tick, Ornithodoros moubata (Acari: Argasidae). Insect Biochem Mol Biol 31: 747-751]. In this study, two defensin isoforms C and D similar to defensins A and B were newly cloned. A total of four defensins have been identified in O. moubata. All four Ornithodoros defensins are coded as prepro-defensins. Ornithodoros defensin genes consist of four exons and three introns, an organization reported in mussel defensins but not insect defensins. Ornithodoros defensin C and D genes are predominantly expressed in the midgut and up-regulated in response to blood feeding. The mature peptide of the previously cloned Ornithodoros defensin A was purified from the midgut lumen, indicating defensin is secreted into the midgut. These findings confirm the involvement of Ornithodoros defensin in midgut immunity.

Amino Acid Sequence↗
PubMed1995

Evidence of common and genus-specific epitopes on Ornithodoros spp. Tick (Acari: Argasidae) salivary proteins.

New 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 tick genera and species' Amblyomma maculatum (Koch), Dermacentor andersoni (Stiles), Dermacentor variabilis (Say), and Ornithodoros moubata (Murray). Absorption of the antisera against an immobilized extract of A. maculatum substantially increased specificity at the genus level. Western blots of electrophoretically separated Ornithodoros salivary gland extract samples were used to further compare the specificity of absorbed and nonabsorbed antitick antisera. The blots demonstrated that many of the Ornithodoros salivary gland extract proteins bear genus specific epitopes. Some differences were noted among the Ornithodoros species examined with respect to the degree of antigenic relatedness with the ixodid ticks.

Animals↗
PubMed1996

Detection and quantification of Ornithodoros-specific anti-tick antibody by competitive inhibition ELISA.

The objective of this study was to develop a highly specific enzyme-linked immunosorbent assay (ELISA) for the serological detection of anti-Ornithodoros tick antibodies in animals. Affinity-purified rabbit anti-Ornithodoros IgG antibodies were employed in indirect competitive inhibition ELISA assays designed to measure the anti-Ornithodoros antibody titers in other animal species using the domestic goat (Capra hircus) as a large animal model. Repeated infestation of goats with Ornithodoros coriaceus was found to elicit the formation of antibodies capable of inhibiting the binding of the Ornithodoros-specific rabbit IgG. Western blot analysis of goat and rabbit anti-tick antisera demonstrated both animal species to respond immunologically to a set of 9 major protein bands in O. coriaceus salivary gland extracts. The results of these experiments demonstrate that a history of animal exposure to O. coriaceus may be detected serologically by competitive inhibition ELISA.

Animals↗
PubMed2001

Two isoforms of a member of the arthropod defensin family from the soft tick, Ornithodoros moubata (Acari: Argasidae).

We previously purified and determined the partial amino acid sequence of a 4 kDa peptide having high homology with scorpion defensin from the hemolymph of adult fed female soft ticks, Ornithodoros moubata. In this study, the full length sequences of two defensin isoforms were obtained. Deduced amino acid sequences reveal a precursor protein of 73 amino acid residues with a mature portion consisting of 37 amino acid residues. This mature peptide contains six cysteine residues conserved in the same location as other invertebrate defensins. Phylogenetic analysis reveals that Ornithodoros defensin is most closely related to scorpion defensin and other more ancient arthropods. Ornithodoros defensin mRNA is constitutively expressed and up-regulated by blood-feeding and bacterial injection. Ornithodoros defensin gene expression occurs mainly in the midgut. This is the first report of the cloning and gene expression of an antibacterial peptide from the Acari.

Amino Acid Sequence↗
PubMed1996

Immune recognition of Ornithodoros tick (Acari: Argasidae) salivary antigens by anti-Psoroptes cuniculi antibodies.

Rabbits infested with either Ornithodoros sp. ticks or Psoroptes cuniculi mites were assayed for anti-tick antibody by enzyme-linked immunosorbent assay. Titration of rabbit serum against Ornithodoros sp. salivary gland extract (SGE) demonstrated both mite- and tick-infested animals to have elevated anti-tick antibody titers. Western blot analysis demonstrated the anti-mite and anti-tick antisera to contain antibodies with affinities for both common and unique subsets of Ornithodoros SGE proteins.

Animals↗
PubMed2002

Savignygrin, a platelet aggregation inhibitor from the soft tick Ornithodoros savignyi, presents the RGD integrin recognition motif on the Kunitz-BPTI fold.

Savignygrin, a platelet aggregation inhibitor that possesses the RGD integrin recognition motif, has been purified from the soft tick Ornithodoros savignyi. Two isoforms with similar biological activities differ because of R52G and N60G in their amino acid sequences, indicating a recent gene duplication event. Platelet aggregation induced by ADP (IC50, 130 nm), collagen, the thrombin receptor-activating peptide, and epinephrine was inhibited, although platelets were activated and underwent a shape change. The binding of alpha-CD41 (P2) to platelets, the binding of purified alpha(IIb)beta3 to fibrinogen, and the adhesion of platelets to fibrinogen was inhibited, indicating a targeting of the fibrinogen receptor. In contrast, the adhesion of osteosarcoma cells that express the integrin alpha(v)beta3 to vitronectin or fibrinogen was not inhibited, indicating the specificity of savignygrin toward alpha(IIb)beta3. Savignygrin shows sequence identity to disagregin, a platelet aggregation inhibitor from the tick Ornithodoros moubata that lacks an RGD motif. The cysteine arrangement of savignygrin is similar to that of the bovine pancreatic trypsin inhibitor family of serine protease inhibitors. A homology model based on the structure of the tick anticoagulant peptide indicates that the RGD motif is presented on the substrate-binding loop of the canonical BPTI inhibitors. However, savignygrin did not inhibit the serine proteases fXa, plasmin, thrombin, or trypsin. This is the first report of a platelet aggregation inhibitor that presents the RGD motif using the Kunitz-BPTI protein fold.

Amino Acid Motifs↗
PubMed2001

Pathogenesis of African swine fever virus in Ornithodoros ticks.

African swine fever virus (ASFV) is the only known DNA arbovirus and the sole member of the family Asfarviridae. It causes a lethal, hemorrhagic disease in domestic pigs. ASFV is enzootic in sub-Saharan Africa and is maintained in a sylvatic cycle by infecting both wild members of the Suidae (e.g. warthogs) and the argasid tick Ornithodoros porcinus porcinus. The pathogenesis of ASFV in O. porcinus porcinus ticks is characterized by a low infectious dose, lifelong infection, efficient transmission to both pigs and ticks, and low mortality until after the first oviposition. ASFV pathogenesis in warthogs is characterized by an inapparent infection with transient, low viremic titers. Thus O. porcinus porcinus ticks probably constitute the most important natural vector of ASFV, although both the mammalian and tick hosts are probably required for the maintenance of ASFV in the sylvatic cycle. The mechanism of ASFV transmission from the sylvatic cycle to domestic pigs is probably through infected ticks feeding on pigs. In addition to O. porcinus porcinus, a number of North American, Central American and Caribbean species of Ornithodoros have been shown to be potential vectors of ASFV.

African Swine Fever↗
PubMed1996

Reproductive bionomics of the soft tick, Ornithodoros turicata (Acari: Argasidae).

The effects of different temperatures and relative humidities (RHs) were tested on various reproductive parameters of Ornithodoros turicata, an argasid tick that inhabits gopher tortoise burrows in Florida, USA. The pre-oviposition, oviposition and incubation periods of the ticks decreased as temperature increased. These periods were also affected by the RH. The number of eggs oviposited was affected significantly by the combined effect of temperature and RH. Fewer eggs were laid by ticks in the 24 degrees C regimes and the 27 degrees C/95% RH regime compared to those in the other temperature/RH groups. There was an inverse relationship between the number of eggs oviposited and the percentage of hatched larvae that was correlated with the temperature and RH. Ticks reared at 27 degrees C/90% RH and 30 degrees C/90% RH laid more eggs than those reared in the other combinations of temperature and humidity but fewer larvae hatched from these eggs. The reproductive fitness index (RFI) values were highest in females held in the 24 degrees C groups and the 30 degrees C/95% RH group, although significantly more larvae hatched at the lower temperatures. The optimum reproductive conditions for O. turicata under laboratory conditions appear to be 24 degrees C and 90-95% RH. While mating occurred at all temperatures, none of the females laid eggs at 22 degrees C. The ticks may move preferentially to low temperatures when not feeding to remain above the critical equilibrium humidity and/or below the critical metabolic level necessary for prolonged survival. However, most female ticks oviposited after 45 days when moved to 27 degrees C/95% RH. Ornithodoros turicata females may have a limited capability to delay oviposition until an optimal microenvironment for egg deposition can be located in the burrow.

Animals↗
PubMed1976

Scanning and transmission electron microscopy of the spermiophores of Ornithodoros ticks: an attempt to explain their motility.

The spermiophores of two tick species, the kangaroo tick, Ornithodoros gurneyi and the cave tick, Ornithodoros tholozani have been examined by scanning and transmission electron microscopy. The anterior end (head) of the spermiophore is a hemisphere covered with a hexagonal network of small projections. The rest of the spermiophore is covered with longitudinal ridges, seen in sections as cellular processes whose membranes are attached only at their anterior ends by specialized 'feet'. In the cytoplasm of the sperm cell body and just beneath the cellular processes are find filaments, which form a continuous layer in O. tholozani and bundles in O. gurneyi. Fibrils tend to be situated beneath the larger cellular processes. In scanning micrographs helical constrictions have been observed in the posterior parts of some spermiophores. It is proposed that certain of the movements observed by light microscopy in living cultures of spermiophores may be explained by contraction of the cytoplasmic filaments seen in the electron microscope.

Animals↗