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Pathogenicity of the entomopathogenic fungus Metarhizium anisopliae (Deuteromycetes) to Ixodes scapularis (Acari: Ixodidae).

The entomopathogenic fungus Metarhizium anisopliae is highly pathogenic to the black-legged tick, Ixodes scapularis. Spore concentrations of 10(8)/ml for engorged larvae and 10(7)/ml for engorged females resulted in 100% tick mortality, 2 wk postinfection. The LC50 value for engorged larvae (concentration to kill 50% of ticks) was 10(7) spores/ml. Metarhizium anisopliae shows considerable potential as a microbial control agent for the management of Ixodes scapularis.

Animals↗

Isolation of Eyach virus (Reoviridae, Colorado tick fever group) from Ixodes ricinus and I. ventalloi ticks in France.

During the spring of 1981, two strains of an identical virus were isolated in Mayenne, France, from Ixodes ricinus L. and Ixodes ventalloi Gil Collado, parasiting a wild rabbit (Oryctolagus cuniculus L.). Virological and serological results indicated that these strains belong to the Colorado tick fever serogroup and are indistinguishable from Eyach virus, a tick-borne virus previously described from West Germany. Study of dsRNA PAGE profiles confirmed these conclusions. The morphology and morphogenesis of French isolates were studied in infected suckling mouse brains showing some peculiar features previously described for Colorado tick fever virus. The importance of the isolation of Eyach virus in France is discussed.

Animals↗

Studies on Bunyaviridae including Zaliv Terpeniya virus isolated from Ixodes uriae ticks (Acarina: Ixodidae) in Brittany, France.

Three viruses were isolated from ticks parasitizing nesting seabirds on Cape Sizun, Brittany, France, during the spring of 1979: Soldado like virus (Bunyaviridae, Nairovirus genus) from Ornithodoros (Alectorobius) maritimus (Argasidae), Zaliv Terpeniya (ZT) virus (Bunyaviridae, Uukuvirus genus) from Ixodes (Ceratixodes) uriae (Ixodidae) parasitizing chicks of the kittiwake (Rissa tridactyla), and a virus of the Sakhalin group from I. (C.) uriae. Certain virological and ultrastructural properties of ZT virus were studied and the antigenic relationships between th French isolate and other UUK serogroup viruses from I. (C.) uriae were analyzed in the complement fixation and immune diffusion tests. Cape Sizun is notable for the unusual presence of both argasied (Ornithodoros) and ixodid (Ixodes) ticks infesting seabirds in adjacent niches in a single locality, where they are infected by different viruses.

Animals↗

Haemaphysalis juxtakochi, Ixodes pararicinus (Ixodidae) and Otobius megnini (Argasidae) in relation to the phytogeography of Argentina.

The phytogeographical distributions of Haemaphysalis juxtakochi, Ixodes pararicinus and Otobius megnini in Argentina are described from material collected mainly from 1978 to the present. H. juxtakochi was found in the northwestern area of the Amazonian domain and in the Chaco, Espinal and Pampean provinces of the Chaco domain. It was detected on Mazama spp., Tapirus terrestris, dog, cattle and on the vegetation. Most findings of I. pararicinus were from mountain rangeland, where it was found on cattle and in a lesser extent on horses. Ticks from Argentina classified as Ixodes ricinus were probably I. pararicinus. O. megnini was detected on cattle an sheep in the Andean Patagonian domain and in the Monte, Chaco and Espinal provinces of the Chaco domain. This tick is considered typical of arid and semiarid conditions, however the findings from the Espinal province where from areas with an annual rainfall over 900 mm.

Animals↗

[Serum antibodies against Ixodes ricinus Spirochaeta in acrodermatitis chronica atrophicans (Herxheimer)].

Using indirect immunofluorescence, IgG antibodies against the recently detected Ixodes-ricinus-spirochaeta, which causes erythema chronicum migrans could be demonstrated in all 21 persons with acrodermatitis chronica atrophicans. Titers were from 1 : 64 to 1 : 1024, specific IgM antibodies were demonstrable in only 5 patients in a titer of 1 : 64. Even after treatment with penicillin high IgG antibody titers of up to 1 : 1024 were found. Fourfold decreases could be found only once for each IgG and IgM antibodies.l Serology indicates that acrodermatitis chronica atrophicans as well as erythema chronicum migrans is caused by the Ixodes-ricinus-spirocheta.

Acrodermatitis↗

Prevalence of Lyme borreliosis spirochetes in ixodid ticks of Japan, with special reference to a new potential vector, Ixodes ovatus (Acari: Ixodidae).

To determine the vectors of Lyme borreliosis in Japan, the ixodid ticks taken in Hokkaido, Fukushima, Nagano, Ehime, and Kochi Prefectures were examined individually for spirochetal infections by culturing their midgut tissues in BSK medium. The cultivable spirochetes identified as Borrelia burgdorferi were detected in Ixodes persulcatus Schulze adults (15.5% of 634), nymph (6.7% of 15) and Ixodes ovatus Neumann adult (9.6% of 188) from Hokkaido, I. ovatus adults (25.5% of 47) from Fukushima, and I. persulcatus adults (21.7% of 143) and I. ovatus adults (27.1% of 85) from Nagano. However, 72 Haemaphysalis spp. from Ehime and Kochi were free from spirochetal infection. I. persulcatus is a vector of Lyme borreliosis in the Far East, but in Japan, I. ovatus may also transmit the spirochetes to human and feral animals.

Animals↗

Inability of Ixodes cookei and Amblyomma americanum nymphs (Acari: Ixodidae) to transmit Borrelia burgdorferi.

The vector competency of Ixodes cookei Packard and Amblyomma americanum (L.) for Borrelia burgdorferi was studied using Syrian hamsters. Ixodes dammini Spielman, Clifford, Piesman & Corwin were used as controls. Darkfield and immunofluorescent examinations of midgut diverticula revealed B. burgdorferi spirochetes in 32 of 36 (88.9%) I. dammini larvae, 5 of 36 (13.9%) I. cookei larvae, and 7 of 36 (19.4%) A. americanum larvae within 48 h after feeding on infected Syrian hamsters. B. burgdorferi were also observed in the midguts of 94 of 107 (87.8%) I. dammini nymphs that developed from the fed larvae. However, none of 30 I. cookei nymphs was positive for spirochetes and only 1 of 60 (1.7%) A. americanum nymphs was found positive for B. burgdorferi. Nymphs of each tick species, reared from larvae that had fed on infected hamsters, were allowed to feed on uninfected hamsters to determine their ability to transmit B. burgdorferi. Transmission was demonstrated only by I. dammini nymphs.

Animals↗

Distribution of the Lyme disease vector, Ixodes dammini (Acari: Ixodidae) and isolation of Borrelia burgdorferi in Ontario, Canada.

Ixodes dammini Spielman, Clifford, Piesman & Corwin was confirmed at Long Point, Lake Erie, Ontario, on small mammals and white-tailed deer and by dragging for ticks. Mean intensities of up to 16.2 larvae and 2.1 nymphs were found on Peromyscus leucopus (Rafinesque), with an overall prevalence of infestation up to 92%. Adult I. dammini (101.6 +/- 77.63) (mean +/- SD) were found on 8 white-tailed deer, Odocoileus virginianus (Zimmerman). The seasonal pattern of recovery of ticks from hosts and the environment resembled that described elsewhere. I. dammini was not found on 952 small mammals trapped at 25 other localities throughout Ontario, although other ticks (Derma-centor variabilis (Packard), Ixodes angustus Neumann, I. marxi Banks, I. muris Bishopp & Smith) were encountered sporadically. I. dammini is not widespread or common in Ontario other than at Long Point. Borrelia burgdorferi was isolated from 10 of 151 P. leucopus; from larval and nymphal I. dammini; and from nymphal and adult D. variabilis, all from Long Point. B. burgdorferi was not recovered from 116 small mammals from localities other than Long Point. Seropositive P. leucopus (indirect fluorescent antibody test titer > or = 1:20) were common (up to 30% prevalence in July 1988, n = 23) on Long Point. Where I. dammini was not found, the prevalence of seroreactors among Peromyscus was 0 (15 sites), < 12% (5 sites), and 29% (1 site); seroprevalence at 1:20 could not be calculated for a further 4 sites examined in 1987. Antibody to B. burgdorferi was also detected in other small mammals at some sites. Such antibody was interpreted as possibly cross-reacting or caused by direct transmission.

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Relative importance of bird species as hosts for immature Ixodes dammini (Acari: Ixodidae) in a suburban residential landscape of southern New York State.

Abundance of birds and their tick parasites were estimated in a residential community located in Westchester County, NY, where Lyme disease is endemic. In total, 36 bird species (416 captures) were collected, of which 25 species (69%) were parasitized by ticks. Ixodes dammini Spielman, Clifford, Piesman & Corwin composed 96.4% of the 1,067 ticks found on birds. The bird species most heavily parasitized was house wren, Troglodytes aedon Vieillot (11.1 Ixodes dammini per bird). Relative density estimates of birds, using fixed circle radius counts, revealed dominance by the American robin, Turdus migratorius L. (29.3%), followed by the common grackle, Quiscalus quiscula (L.) (9.3%). Bird density estimates were combined with tick abundance data to calculate an importance value for each bird species as a host for immature I. dammini. The American robin was most important, accounting for 72.7% of all larval I dammini found on birds, followed by the common grackle (8.2%) and the house wren (5.9%). Both the American robin and house wren are reservoir competent for the Lyme disease spirochete Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner and therefore may contribute to the risk of Lyme disease for humans. During August when larvae were most prevalent, 39% of the American robins and 70% of the common grackles were observed on lawns. These species are probable contributors to nymphal I. dammini populations found on lawns.

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Susceptibility of Ixodes persulcatus and I. ovatus (Acari: Ixodidae) to Lyme disease spirochetes isolated from humans in Japan.

Susceptibility of Ixodes persulcatus Schulze and Ixodes ovatus Neumann to Lyme disease spirochetes isolated from humans was studied under laboratory conditions. Six isolates (JEM3, JEM4, JEM5, JEM6, JEM7, and JEM8) from patients in Japan were used for the study. Mongolian jirds were inoculated intraperitoneally with each of the isolates. Larval ticks of either I. persulcatus or I. ovatus were allowed to feed on the jirds and reared for development into nymphs. In all human isolates examined, the replete larvae of both tick species ingested spirochetes. However, retention of the spirochetal infections through the molting process was observed only in I. persulcatus. These data clearly indicate that I. persulcatus is susceptible to the spirochetes that are pathogenic to humans. The principal vector of Lyme disease to humans in Japan is considered to be I. persulcatus.

Animals↗

Prevalence of Lyme borrelia in ticks, especially Ixodes persulcatus (Acari: Ixodidae), in central and western Japan.

Prevalence of Lyme Borrelia in unfed ticks was surveyed in central and western Japan during spring from 1991 to 1993. The tick fauna was diverse; ticks obtained consisted of four genera and more than 12 identified species, and both southern and northern species coexist with altitudinal separation. Midguts of ticks were cultured in BSK medium for spirochetal isolation. Borrelia-positive rates for adults of both a common species, Ixodes ovatus Neumann, and a northern species, Ixodes persulcatus Schulze, in the extreme western part of the Japanese central mountainous zone (Fukui and Gifu prefectures) were 18.1 and 12.9%, respectively. A Borrelia-positive nymph of Haemaphysalis flava Neumann also was found for the first time in Japan. In contrast, I. persulcatus in southwestern Japan was localized in mountains with elevations over 800 m and was determined negative for Borrelia, whereas I. ovatus was highly positive (28.8%). These Borrelia isolates were diverse in typing of protein profiles. Our results reveal that I. persulcatus-borne Borrelia derived from northern Japan is kept within the limits of the western extremity of the central mountainous zone.

Animals↗

Fall and rise of Lyme disease and other Ixodes tick-borne infections in North America and Europe.

Lyme disease is a spirochaetal infection with acute and chronic manifestations. Lyme disease and other infections transmitted by Ixodes species ticks are increasing in temperate and Holarctic regions of the Northern hemisphere. These zoonotic infections are most commonly acquired in suburban residential areas and outdoor recreation areas close to cities. Different enzootic cycles, which include a variety of large and small mammals as well as migratory birds, maintain and distribute in nature the Borrelia species that cause Lyme disease. The rise in cases of Lyme disease and the other Ixodes tick-borne infections is, in part, the consequence of reforestation and the increase in deer populations in developed countries.

Europe↗

A case of tick-bite from Ixodes ovatus Neumann--a report from west Japan.

A 70-year-old male forestation worker had a tick-bite on the lower abdominal skin. The bite was treated by surgical excision of the tick together with the surrounding skin. The tick was identified as Ixodes ovatus Neumann through investigation of its morphological characteristics. This patient is the fourth case of a tick-bite from Ixodes ovatus Neumann in western Japan.

Aged↗

Nocturnal detachment of the tick Ixodes hexagonus from nocturnally active hosts.

To determine whether the pattern of engorgement of Ixodes hexagonus Leach (Acarina: Ixodidae) in Central Europe may influence host specificity, the host relationships of the sub-adult stages of this tick were examined and the time of detachment compared with the activity patterns of various candidate vertebrate hosts. The main hosts for I. hexagonus appear to be hedgehog and fox. This tick species seems to be incapable of feeding on any rodent commonly encountered in the study region, or on reptiles or birds. Virtually all of these ticks detach during the scotophase, becoming replete mainly during the late evening and early morning hours, regardless of the kind of host or of the time of attachment. These nocturnally detaching ticks, paradoxically, focus their feeding on nocturnally active hedgehogs and foxes, in spite of the possibility that such behaviour might cause them to disperse from the nests of the host. Dispersion is prevented, however, by the tendency of these ticks to detach while their host naps. The tick-host association of I. hexagonus with hedgehogs may serve to perpetuate such zoonotic, Ixodes-borne infections as Lyme disease.

Animals↗

Borrelia burgdorferi infection in Ixodes ricinus from habitats in Denmark.

A total of 2647 ticks of the genus Ixodes was sampled by flagging the vegetation in thirty-one sites in eastern Jutland, Denmark. All ticks were identified as Ixodes ricinus Linnaeus. A total of 317 ticks (202 nymphs and 115 adults) from three different sites were examined for the spirochaete Borrelia burgdorferi Johnson et al. by indirect fluorescent antibody staining; the frequency of infection varied from 7% to 22%. It is concluded that I. ricinus, known to be the most common tick in Denmark, is the vector largely responsible for the transmission of B. burgdorferi in this country.

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Infestation in the dog by the paralysis tick, Ixodes holocyclus. 4. Cardiovascular effects.

To determine the extent and significance of changes in heart rate and rhythm noticed previously in dogs paralysed with Ixodes holocyclus, two studies were undertaken. In one the electrocardiogram was recorded at stages throughout the disease and the traces analysed for changes, while in the second a detailed study of the effect of Ixodes holocyclus on the cardiovascular system was undertaken. The electrocardiographic changes were extremely variable between stages and between dogs. Generally, if a dysrhythmia occurred in stages 1, 2 or 3 it tended to be sinus tachycardia, ventricular tachycardia or sinus arrest. In stage 4 sinus arrest, sinus bradycardia, or sinus or ventricular tachycardia were the prominent dysrhythmias, whereas in stage 5 sinus bradycardia predominated. Cardiovascular measurements indicated an increase in peripheral vascular resistance leading to a significant elevation in mean arterial pressure at all stages of the disease. Cardiac output was decreased significantly only at stage 2, although it was below the control measurements at all stages. Pulmonary arterial pressure was significantly elevated at stages 2, 3 and 4 due most probably to an increase in pulmonary vascular resistance. Myocardial contractility was not significantly changed throughout the disease. The changes observed in the electrocardiogram and the cardiovascular system in stages 1, 2 and 3 are unlikely to be due to hypoxia and could represent dysfunction of the autonomic nervous system. During stages 4 and 5 oxygen levels were below normal and the bradycardia seen terminally is almost certainly due to hypoxaemia.(ABSTRACT TRUNCATED AT 250 WORDS)

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Detection of Borrelia burgdorferi DNA in museum specimens of Ixodes dammini ticks.

In order to investigate the potential for Borrelia burgdorferi infection before the recognition of Lyme disease as a clinical entity, the polymerase chain reaction (PCR) was used to examine museum specimens of Ixodes dammini (deer ticks) for the presence of spirochete-specific DNA sequences. One hundred and thirty-six archival tick specimens were obtained representing various continental U.S. locations; DNA sequences characteristic of modern day isolates of B. burgdorferi were detected in 13 1940s specimens from Montauk Point and Hither Hills, Long Island, New York. Five archival specimens of Dermacentor variabilis (dog tick) from the same collection and 118 Ixodes specimens from other endemic and nonendemic sites were negative. These data suggest that the appearance of the Lyme disease spirochete in suitable arthropod vectors preceded, by at least a generation, the formal recognition of this disease as a clinical entity in the United States.

Animals↗

Rickettsia monacensis sp. nov., a spotted fever group Rickettsia, from ticks (Ixodes ricinus) collected in a European city park.

We describe the isolation and characterization of Rickettsia monacensis sp. nov. (type strain, IrR/Munich(T)) from an Ixodes ricinus tick collected in a city park, the English Garden in Munich, Germany. Rickettsiae were propagated in vitro with Ixodes scapularis cell line ISE6. BLAST analysis of the 16S rRNA, the citrate synthase, and the partial 190-kDa rickettsial outer membrane protein A (rOmpA) gene sequences demonstrated that the isolate was a spotted fever group (SFG) rickettsia closely related to several yet-to-be-cultivated rickettsiae associated with I. ricinus. Phylogenetic analysis of partial rompA sequences demonstrated that the isolate was genotypically different from other validated species of SFG rickettsiae. R. monacensis also replicated in cell lines derived from the ticks I. ricinus (IRE11) and Dermacentor andersoni (DAE100) and in the mammalian cell lines L-929 and Vero, causing cell lysis. Transmission electron microscopy of infected ISE6 and Vero cells showed rickettsiae within the cytoplasm, pseudopodia, nuclei, and vacuoles. Hamsters inoculated with R. monacensis had immunoglobulin G antibody titers as high as 1:16,384, as determined by indirect immunofluorescence assay. Western blot analyses demonstrated that the hamster sera cross-reacted with peptides from other phylogenetically distinct rickettsiae, including rOmpA. R. monacensis induced actin tails in both tick and mammalian cells similar to those reported for R. rickettsii. R. monacensis joins a growing list of SFG rickettsiae that colonize ticks but whose infectivity and pathogenicity for vertebrates are unknown.

Actins↗