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At least 307 records · Page 17Linked to original sources

A comparison of the tick burdens of wild animals in a nature reserve and on an adjacent farm where tick control is practised.

Acaricidal treatment of cattle, sheep and goats on a farm in Valley Bushveld in the Grahamstown district resulted in a reduction in the numbers of certain tick species on kudu (Tragelaphus strepsiceros), scrub hares (Lepus saxatilis) and crowned guinea fowl (Numida meleagris) on the same farm. The tick species most severely affected was Amblyomma hebraeum, while Haemaphysalis silacea, Hyalomma marginatum rufipes and Rhipicephalus appendiculatus were affected to a lesser extent. Rhipicephalus glabroscutatum and Rhipicephalus oculatus appeared to be unaffected.

Agriculture↗

[Immunochemical characteristics of the antigens of a variant tick-borne encephalitis virus adapted to Hyalomma plumbeum ticks].

A comparative study of immunochemical properties of a preparation of the virion antigen of a variant of tick-borne encephalitis (TBE) virus adapted to H. plumbeum ticks (clone 718/574) and the parental TBE strain revealed the following features: (1) immunoelectrodiffusion test revealed no immunoprecipitation rockets directed towards cathode in the clone 718/574 preparation; anodic precipitates differed in shape from those of the parental strain; (2) diffuse precipitation in agar showed a reaction of incomplete identity between the virion antigen of clone 718/574 and the parental strain antigen, the clone 718/574 antigen forming only one precipitation band in contrast to two precipitation bands of the parental strain; (3) immune electron microscopy demonstrated a peculiar nature of the halo-overlay by immunoglobulins of clone 718/574 virions differing from that of the parental strain.

Adaptation, Physiological↗

The brown ear tick Rhipicephalus appendiculatus Neumann (Acarina: Ixodidae) and associated tick species on wild and domestic hosts at Muguga, Kenya.

During a study of an experimental population of Rhipicephalus appendiculatus and its transmission of bovine theileriosis to cattle, some supplementary information was obtained on the role of rodents and the small carnivores in the development and maintenance of R. appendiculatus populations. Observations were also made on other common tick species found on these hosts. A total of 530 individual hosts were examined during the 4-yr period, of which the majority included, among the carnivores, the white-tailed mongoose (Ichneumia albicauda), the large spotted genet (Genetta tigrina) and the zorilla (Ictonyx striatus). Among the 482 rodents 95% included Otomys irroratus, Rhabdomys pumilio and Lophuromys flavopunctatus. While all stages of R. appendiculatus thrived on cattle the role of rodents and carnivores was negligible. Similarly, while the other tick species like H. leachi group, immatures of R. hurti/jeanneli group and I. thomasae avoided cattle, they thrived on the carnivores and rodents. However, the adults of R. hurti and R. jeanneli preferred cattle to carnivores and rodents.

Animal Population Groups↗

[Zoonoses transmitted by ticks in forest workers (tick-borne encephalitis and Lyme borreliosis): preliminary results].

In order to investigate the diffusion of infections transmitted by ticks (TBE and Lyme borreliosis) in forest workers, a serological investigation was carried out in the Province of Trento (Northern Italy) on the sera of 465 subjects at potential risk (foresters, hunters, woodcutters, gamekeepers). Antibodies for TBE virus were found in 5 subjects (1.07%) working in the same area, and antibodies for Borrelia burgdorferi were found in 15 subjects (3%). All three clinical cases of TBE identified in the Province of Trento reported that they had been bitten by ticks in the same geographical area. The presence of specific antibodies for TBE virus was tested on the sera of animals grazing in several areas: 4 positive cases were observed in the same area as the human cases reported above.

Agricultural Workers' Diseases↗

Toxic effect of endocytobionts from Dermacentor reticulatus ticks in three tick species after in vivo application.

The endocytobionts from ovaries of partially engorged female Dermacentor reticulatus ticks, inoculated introcoelomally into females of three tick species, D. reticulatus, Ixodes ricinus and Haemaphysalis inermis, caused considerable morphological alterations in the examined cells and tissues of the synganglion, fat body, tracheal complex and ovary of these recipients.

Animals↗

Lyme disease: additional evidence of widespread distribution. Recognition of a tick-borne dermatitis-encephalitis-arthritis syndrome in an area of known ixodes tick distribution.

Lyme disease is a process of unknown etiology that has been linked to bites of ticks of the Ixodes ricinus complex. Central Minnesota is an area of known Ixodes dammini distribution. This case represents the first recognition of Lyme disease from this area. This case presented as a fluctuating meningoencephalitis with superimposed cranial neuropathy. The characteristic skin lesion, erythema chronicum migrans, was recognized by history, and oligoarticular arthritis subsequently developed. Physicians practicing in areas of known Ixodes tick distribution outside of the northeastern United States (coastal areas of Oregon and California, central Minnesota, northwestern Wisconsin, northwestern Utah, certain parts of ontario) should be alert to this disease and aware fo the variety of symptom complexes that are possible with it.

Adult↗

NMR solution structure of the recombinant tick anticoagulant protein (rTAP), a factor Xa inhibitor from the tick Ornithodoros moubata.

The solution structure of the recombinant tick anticoagulant protein (rTAP) was determined by 1H nuclear magnetic resonance (NMR) spectroscopy in aqueous solution at pH 3.6 and 36 degrees C. rTAP is a 60-residue protein functioning as a highly specific inhibitor of the coagulation protease factor Xa, which was originally isolated from the tick Ornithodoros moubata. Its regular secondary structure consists of a two-stranded antiparallel beta-sheet with residues 22-28 and 32-38, and an alpha-helix with residues 51-60. The relative orientation of these regular secondary structure elements has nearly identical counterparts in the bovine pancreatic trypsin inhibitor (BPTI). In contrast, the loop between the beta-sheet and the C-terminal alpha-helix as well as the N-terminal 20-residue segment preceding the beta-sheet adopt different three-dimensional folds in the two proteins. These observations are discussed with regard to the implication of different mechanisms of protease inhibition by rTAP and by Kunitz-type protein proteinase inhibitors.

Amino Acid Sequence↗

Langerhans cells trap tick salivary gland antigens in tick-resistant guinea pigs.

In the infested skin of tick-resistant guinea pigs, indirect immunofluorescence techniques have revealed that antigens from the ticks' salivary glands are associated with discrete dendritic cells in the epidermis. Evidence is presented to support the suggestion that these antigen-retaining cells are Langerhans cells.

Adenosine Triphosphatases↗

Gram-negative bacteria from the camel tick Hyalomma dromedarii (Ixodidae) and the chicken tick Argas persicus (Argasidae) and their antibiotic sensitivities.

A total of nine species of gram-negative bacteria were isolated from organs and haemolymph of the hard tick Hyalomma (Hyalomma) dromedarii and the soft tick Argas (Persicargas) persicus. Four species namely Serratia liquefaciens, Stenotrophomonas maltophilia, Klebsiella ornithinolytica and Aeromonas hydrophila were isolated from H. dromedarii and five species namely Rahnella aquatilis, Pseudomonas fluorescens, Enterobacter cloacae, Chryseomonas luteola and Chryseobacterium meningosepticum were isolated from A. persicus. Isolated bacteria were identified using the analytical profile index 20E. Disk diffusion test was carried out on all isolated bacteria to determine antibiotic sensitivity of chloramphenicol, amoxillin/clavulanic acid, neomycin, streptomycin, triplesulphur tetracycline and nitrofurantion. The results were discussed.

Animals↗

Transmission of tick-borne bunyaviruses by cofeeding ixodid ticks.

Palma and Bhanja bunyaviruses replicated in Dermacentor marginatus, D. reticulatus, Rhipicephalus sanguineus, R. appendiculatus and Ixodes ricinus ticks after parenteral inoculation and appropriate incubation and feeding. Palma virus was transmitted to D. marginatus and D. reticulatus males, D. reticulatus and R. sanguineus females, and R. appendiculatus nymphs while cofeeding with infected ticks on laboratory mice. Bhanja virus was transmitted to D. marginatus males and R. appendiculatus nymphs. Laboratory mice developed low levels of viraemia detectable only by intracranial (i.c.) inoculation of newborne laboratory mice.

Animals↗

Replication of tick-borne encephalitis (TBE) virus in Ixodes ricinus ticks.

The influence of external factors on virus carriage of Ixodes ricinus ticks in laboratory and in nature was studied. In laboratory experiment, only one nymph was positive for the presence of virus on 120th day after metamorphosis. The virus titer was 10(2) mouse i.c. LD50/0.03 ml. Transmission experiments were negative. The nymphs were positive on 75th, 111th and 159th day after metamorphosis, always chilling in the field experiment. The titres of virus varied from the lowest detectable amount value to 10(3.6) mouse i.c. LD50/0.03 ml. The transmission of virus was positive in two cases.

Animals↗

[Immunological structure of the population following the extermination of ticks in a natural focus of tick-borne encephalitis].

Ten years after the break of the chain of transmission of tick-borne encephalitis virus the level of the immune stratum of the local population declined from 59% to 39%. A decrease in the number of seroconversions was found in all the age groups but was particularly noticeable in the rural residents aged 10-30 years (39% and 13%), the mean titres declining from 1.8 log2 to 0.6 log2. In the rural residents over 30 years of age the immune stratum declined from 71% to 54%, the mean antibody titres from 3.4 to 2.5 log2. In subjects repeatedly infected in the natural focus, antihemagglutinins persisted for 10 years (the observation period).

Adolescent↗

Genome size and organization in the blacklegged tick, Ixodes scapularis and the Southern cattle tick, Boophilus microplus.

Genome sizes and the organization of repetitive DNA were determined in the hard ticks Ixodes scapularis and Boophilus microplus using reassociation kinetics. The I. scapularis genome contains approximately 2.15 pg (2.1x10(3) Mbp) of DNA and consists of no foldback (FB), 27% highly repetitive (HR), 39% moderately repetitive (MR), and 34% unique DNA. The B. microplus genome contains 7.5 pg (7.1x10(3) Mbp) DNA, and consists of 0.82% FB, 31% HR, 38% MR, and 30% unique DNA. In both species, repetitive sequences occur in a mixture of long and short period interspersion but most (65-80%) of the DNA follows a pattern of short period interspersion. Genome size and organization in the three tick species so far examined are distinct from other arthropods in having a greater proportion of MR, a lower proportion of unique and HR DNA of very low sequence complexity.

Animals↗

Coinoculation of Borrelia spp. with tick salivary gland lysate enhances spirochete load in mice and is tick species-specific.

C3H/HeN mice were inoculated with 10(6) spirochetes, either Borrelia burgdorferi strain N40 or the Portuguese strain of B. lusitaniae, PotiB2. Mice receiving spirochetes coinoculated with salivary gland lysate (SGL) demonstrated significantly higher spirochete loads in target organs as measured by quantitative real-time polymerase chain reaction. This effect was tick dependent, in that Ixodes ricinus SGL specifically enhanced B. lusitaniae load, whereas I. scapularis SGL specifically increased B. burgdorferi N40 load, but did not significantly affect the dissemination of B. lusitaniae. Protein profile analysis indicated at least 5 major protein differences between I. scapularis and I. ricinus SGL, which can possibly account for this specific tick-spirochete interaction.

Animals↗