Rickettsia slovaca and Rickettsia raoultii in Dermacentor marginatus and Dermacentor reticulatus ticks from Slovak Republic

Rickettsiae, obligate intracellular Gram-negative bacteria, responsible for mild to severe diseases in humans are associated with arthropod vectors. Dermacentor marginatus and Dermacentor reticulatus are known vectors of Rickettsia slovaca and Rickettsia raoultii distributed across Europe. A total of 794 D. marginatus, D. reticulatus and Ixodes ricinus adult ticks were collected from the vegetation, removed from horses, sheep, goats and dogs in Slovakia. The DNA of Rickettsia sp. was found in 229 ticks by PCR amplifying parts of gltA, ompA and sca4 genes. Next analyses of Rickettsia-positive samples by PCR-RFLP and/or sequencing showed D. reticulatus ticks were more infected with R. raoultii and D. marginatus were more infected with R. slovaca. The prevalence of R. raoultii was 8.1-8.6% and 22.3-27% in D. marginatus and D. reticulatus, respectively. The prevalence of R. slovaca was 20.6-24.3% in D. marginatus and 1.7-3.4% in D. reticulatus. Intracellular growth of R. raoultii isolate from D. marginatus tick was evaluated by rOmpA-based quantitative SybrGreen PCR assay. The highest point of multiplication was recorded on the 7th and 8th day postinfection in Vero and L929 cells, respectively. R. raoultii was transmitted during feeding of R. raoultii-positive ticks to guinea pigs and subsequently rickettsial infection was recorded in all organs, the highest infection was in spleen, liver and heart. Our study describes the detection and isolation of tick-borne pathogens R. raoultii and R. slovaca, show that they are spread in Slovakia and highlight their risk for humans.     

Evidence for the reproductive isolation of Dermacentor marginatus and Dermacentor reticulatus (Acari: Ixodidae) ticks based on cross-breeding, morphology and molecular studies

The species status of Dermacentor marginatus and Dermacentor reticulatus was evaluated by scanning electron microscope (SEM) examination of adult ticks, cross-breeding experiments and molecular biological analysis of eggs derived from transspecific pairings. The SEM investigations including the morphometric quantification of phenotypic features resulted in an unequivocal differentiation of adult D. marginatus and D. reticulatus ticks. The cross-breeding experiments demonstrated that irrespective of whether female ticks of both species were applied with con- or transspecific male ticks or without males to sheep, they engorged and laid eggs. The larvae, however, developed only in eggs which originated from conspecific matings. A nested polymerase chain reaction (PCR) of the second internal transcribed spacer (ITS2) using the DNA of eggs from transspecific pairings and sequencing of the PCR products revealed two different genotypes. The genotypes of eggs originating from D. marginatus and D. reticulatus females of these pairings differed. However, the eggs deposited by D. marginatus always possessed the same two genotypes as did the eggs produced by D. reticulatus. These results argue for a strict reproductive isolation of D. marginatus and D. reticulatus and, therefore, for a separate species status.     

Ixodes ricinus is the dominant questing tick in forest habitats in Romania: the results from a countrywide dragging campaign

In 2010 and 2011, questing ticks were collected from 188 forested locations in all the 41 counties of Romania using the dragging method. The total of 13,771 ticks collected belonged to eleven species: Ixodes ricinus (86.9?%), Dermacentor marginatus (9.5?%), Haemaphysalis punctata (2.6?%), H. concinna (0.6?%), H. sulcata (0.3?%), H. parva (0.1?%), Hyalomma marginatum (0.02?%), D. reticulatus (0.02?%), I. crenulatus (0.007?%), I. hexagonus (0.007?%) and I. laguri (0.007?%). Ixodes ricinus was present in 97.7?% (n?=?180) of locations, occurring exclusively in 41.7?% of the locations, whereas it was the dominant species in 38.8 % of the other locations, accounting for over 70?% of the total tick community. The following most common questing ticks were D. marginatus, H. punctata and H. concinna. Ixodes ricinus co-occurred with one, two or three sympatric species. The occurrence of D. reticulatus in forested habitats from Romania was found to be accidental.     

The action of carbon dioxide gas in high concentrations on ixodid ticks

The ticks Ixodes persulcatus, Dermacentor reticulatus, D. marginatus were affected by 50, 70, 80 and 90% CO2 at 18 to 26 degrees. The higher the gas concentration and the lower the temperature, the quicker and the deeper was anesthesia. Additional tests have shown that response to CO2 depends on the water balance level determining the position of atrial valves. The response of some individuals to CO2 can change depending on the tick state during the experiment.     

Evaluation of the Possible Role of Ixodid Ticks in Natural Tularemia Foci in the Forest-Steppe Zone of European Russia

Entomological Review - Adult ixodid ticks Dermacentor reticulatus (Fabricius, 1894), D. marginatus (Sulzer, 1776) and Ixodes ricinus (Linnaeus, 1758), collected from vegetation in April–May...     

Species composition, distribution, and ecological preferences of the ticks of grazing sheep in north-central Spain

The distribution and ecological preferences of tick (Acari: Ixodidae) parasites of grazing sheep in the region of Aragón (north-central Spain) were surveyed on flocks four times a year and mapped into a 5 x 5 km grid. Nine tick species were found. These were species of the Rhipicephalus sanguineus group (about 95% of them Rhipicephalus turanicus Pomerantsev, in 91% of cells of the grid), Rhipicephalus bursa Canestrini & Fanzago (79% of cells), Dermacentor marginatus (Sulzer) (58% of cells), Haemaphysalis punctata Canestrini & Fanzago (74% of cells) and Ixodes ricinus (Linnaeus) 14% of cells. Other species weakly represented in the surveys were Dermacentor reticulatus (Fabricius), Haemaphysalis sulcata Canestrini & Fanzago and Hyalomma m. marginatum Koch. Data on temperature, Normalized Difference Vegetation index (NDVI), topography, vegetation categories and plant productivity were used to build models of distribution and abundance of D. marginatus, H. punctata, R. bursa and R. turanicus. The occurrence models largely incorporated climatic variables and had good discrimination ability (P < 0.0001 for every modelled species, correct classification rate or sensitivity within 0.89 and 0.99), whereas the abundance models had a lower explanatory power. These models are relevant in the understanding of the variables composing the main distribution patterns, but they are unable adequately to predict the density. Abundance models produce good predictions in cells with low tick density, whereas poor correlation is observed in sites with high tick abundance. Several causes may be responsible for this low predictive power of the abundance models. Model output might be sensible to host density, to local farming practices, or to the size of the grid used to refer the results of the survey. In the latter case, small patches may support locally important populations of ticks, influencing largely the results of the survey. These patches of particular abiotic conditions, or supporting large host densities, may have been undetected at the resolution of the survey, thus obscuring the impact of the predictive variables.     

Ixodid ticks of Pavlodar Province and their participation in the circulation of tularemia infection

Investigations carried out in Pavlodar Province have shown that 7 species of ixodid ticks, Ixodes crenulatus, I. lividus, I. persulcatus, I. laguri laguri, Dermacentor marginatus, D. reticulatus, Haemaphysalis concinna, and one brought species, Hyalomma asiaticum, parasitize domestic animals and wild mammals. Maximum activity of pasture ticks of the genus Dermacentor falls on the end of April--beginning of May, that of H. concinna on the beginning of June. The growth in the abundance of pasture ticks, recorded during the last years, is favoured by the increase in the cattle live stock, its seasonal movements and pasture area reduction. Natural nidi of tularemia become more active. Since 1977 221 cultures of tularemia agent have been isolatid from pasture ticks. H. concinna takes the most active part in the infection circulation.     

Experimental tick-borne rickettsiosis in murine rodents

The comparative study of the duration and level of rickettsiemia in wild rodents, natural carriers of rickettsiosis, after their experimental infection with Rickettsia sibirica has been carried out. All those species under study (common voles, meadow mice and great gerbils) have been found to be faintly susceptible to this infective agent. Large infective doses produce no visible signs of the disease in these animals, rickettsiemia for a short time and its level is not high. Great gerbils have been found to be most susceptible, and meadow mice least susceptible to R. sibirica. Different species also show differences in the immune transformation of the body.     

Suppression of cotton leafworm Spodoptera litura, flower beetle Mylabris pustulata and red cotton bug Dysdercus cingulatus by Rhynocoris marginatus (Fabr.) (Het., Reduviidae) in cotton field cages

Abstract: Mass-reared reduviid, Rhynocoris marginatus was released in large-sized cotton field cages against three cotton pests, Spodoptera litura, Mylabris pustulata and Dysdercus cingulatus . Pest species were introduced into separate cages in the absence of other pests, parasitoids and predators. Control experimental cages without R. marginatus were maintained for each prey set up during the evaluation period. R. marginatus greatly reduced the infestation of S. litura (57.5%), M. pustulata (52.3%) and D. cingulatus (45.8%). The leaves, flower and boll damages (32%, 35% and 28% by S. litura, M. pustulata and D. cingulatus , respectively) and seed-cotton yield loss (1.4, 1.6 and 1.25 times in S. litura, M. pustulata and D. cingulatus infested cages, respectively) were reduced by R. marginatus compared with such fields without R. marginatus . The field observations suggest this predator's pest suppression and damage reduction efficacy.     

New data on the ixodid tick fauna of the western Pamirs

Dermacentor raskemensis and Haemaphysalis pospelovashtromae were first recorded from the West Pamirs in the flood-land of the Gunt river at the height of 2700 m above the sea level. The ticks were collected from sheep, on which in addition to the above species D. marginatus was found. In the Rushansk region of the Mountain-Badakhshan district at the height of 2100 to 2300 m Rhipicephalus pumilio, R. turanicus and Hyalomma plumbeum were collected from domestic sheep and goats.     

Tick species parasitizing people in an area endemic for tick-borne diseases in north-western Italy

In 1995 and 1996, 318 ticks were recovered from 240 people in Liguria (Province of Savona, Italy). Most of the ticks (284; 89.3%) were sheep ticks, Ixodes ricinus. Rhipicephalus sanguineus (31; 9.8%) and Dermacentor marginatus (3; 0.9%) were also recorded. All three life stages of I. ricinus were found on humans while only nymphs and adults of R. sanguineus and adults of D. marginatus were collected. Human tickbites were most frequent in the municipalities of the Province where roe deer density was highest. The number of tickbites in this area was about 500 per 100,000 residents over the period of observation. Most cases of tickbite were observed in children (11.2%), students (25.6%), workers (22.4%) and retired people (24%). Although ticks were recovered from people throughout the year, the highest frequencies of I. ricinus bites were in May, June and July. In the study area natural hosts were also studied. Six tick species were identified (I. ricinus, I. hexagonus, D. marginatus, R. bursa, R. sanguineus, R. turanicus). I. ricinus and R. sanguineus were the most abundant species. I. ricinus was recorded more frequently from ruminants particularly roe deer, while R. sanguineus was found to be associated with the dog.     

Results of the 20-year study of tick-borne encephalitis in Crimea

The history of tick-borne encephalitis (TBE) study in the Crimea was retraced and the possibility of introduction of TBE virus to the Crimea in the process of the acclimatization of vertebrates from areas enzootic for TBE is discussed. The foci of TBE were found throughout the whole of the mountain forest zone of the Crimea and coincided with the habitat area of lxodes ricinus, the main vector of TBE. Such ticks as Dermacentor reticulatus, D. marginatus and Hyalomma marginatum were also found to take part in the circulation of the virus. Among the residents of the mountain forest zone, 13.9% were found to have immunity to TBE, testifying to the wide contact of the population with the pathogen. TBE morbidity had pronounced seasonal character and the morbidity rate was low with the prevalence of mild clinical forms. The characteristic feature of the virus population was polymorphism: strains identical to the Far-Eastern strains Sofyin (about 60-70%) and strains differing in their antigenic structure circulated here.     

A study of possible transovarial and transphase transmission of borreliae by the tick Dermacentor reticulatus (Ixodidae)

A study of possible transovarial and transphase transmission of borreliae by the tick Dermacentor reticulatus is carried out. The possibility of borreliae transmission by the ticks of this species being infected spontaneously as well as experimentally is shown in principle. Although borreliae are preserved in the organism of D. reticulatus, low values of the infestation are established in the different stages of D. reticulatus development and in all steps of the study. D. reticulatus may be involved in the process of borreliae circulation in natural foci of tick-born borreliosis, but this species has no a significant importance for the maintenance of it.     

Notes on the Genus Osmanthus Lour. in China

In the present paper a new species, Osmanthus gracilinervis Chia ex R. L. Lu, is described from Guangxi. The new species is also distributed in Guangdong, Jiangxi, Zhejiang, Hunan and Sichuan. Based on the analysis of a great deal of specimens, eight species, i.e. Osmanthus corymbosus H. W. Li, O. longispermus H. T. Chang, O. angustifolius H. T. Chang, O. triandrus H. T. Chang, O. longicarpus H. T. Chang, O. omeiensis Fang ex H. T. Chang, O. nanchuanensis H. T. Chang and 0. cylindricus H. T. Chang, are reduced as the synonyms of O. marginatus (Champ. ex Benth.) Hemsl. var. marginatus. O. longissimus H. T. Chang and O. pachyphyllus H. T. Chang are respectively reduced to varieties of O. marginatus, i.e.O. marginatus var. longissimus (H.T. Chang) R. L. Lu and var. pachyphyllus (H. T.Chang) R. L. Lu. And finally O. maximus H. T. Chang is treated in this paper as a synonym of O. matsumuranus Hayata.     

革蜱成虫哈氏器的扫描电镜观察

本文报道了用扫描电镜观察革蜱属8种成虫的哈氏器.其中三种成虫(阿坝革蜱D. ahaensis、金泽革蜱D. auratus和中华革蜱D. sinicus)的哈氏器结构是首次报道,并与其他属6种成虫的哈氏器进行了比较,以阐明其形态特征及其在分类中的意义.另外,还将这14种成虫哈氏器与各自未成熟期的哈氏器进行了比较.分析和讨论了同种不同时期哈氏器结构的异同.东洋区的金泽革蜱和古北区的革蜱种类间,在孔毛形状,位置及基盘数目上有明显差别,而后者中,边缘革蜱D. marginatus的孔毛位于近端外侧,草原革蜱D. nuttalli和网纹革蜱D. reticulatus的孔毛位于远瑞外侧,其余种类无明显差别.     

Acarological studies in two protected areas of Central Italy

In the present note are reported the results of preliminary studies on tick distribution in two wildlife areas of Abruzzo (National Park of Abruzzo, a mountainous area, approximately 40,000 ha, in Central Apennines, interesting Abruzzo, Latium and Molise regions) and Latium (Capocotta-Castel Porziano Presidential reserve, on the Tyrrhenian coast, 30 km from Rome). Sampling of ticks from domestic and wild mammals as well as from vegetation, was performed in three different areas of the National Park in 1995. Tick species identified include Rhipicephalus bursa, R. sanguineus, Hyalomma marginatum, Haemaphysalis punctata, Dermacentor marginatus, Ixodes ricinus, I. hexagonus. The presence of I. ricinus was discontinuous and sporadic. In Capocotta estate, samplings were performed bimonthly from March to November 1997 in an restricted area (1 ha) with typical Mediterranean flora and fauna. The following species were collected: I. ricinus, Haemaphysalis concinna, D. marginatus, R. bursa, Hy. marginatum. There was a high dominance of I. ricinus and H. concinna.     

Tick infection rates with Borrelia Ixodes ricinus versus Haemaphysalis concinna and Dermacentor reticulatus in two locations in eastern Germany

Unfed nymphal Ixodes ricinus, Haemaphysalis concinna, and adult Dermacentor reticulatus were collected in two locations of Saxony in July and September 1991 by flagging. In July, the abundance of nymphal I. ricinus was about 2-3 times higher than that of nymphal H. concinna, a time of the year when nymphs of both species are reported to have a seasonal peak of activity. No D. reticulatus were flagged concurrently. In September, host-seeking activity of nymphal I. ricinus was again quite high as was that of adult D. reticulatus but only low numbers of nymphal H. concinna were collected. The flagged ticks were individually examined for Borrelia by an indirect immunofluorescence assay (I. ricinus: n = 414; H. concinna: n = 96; D. reticulatus: n = 116). The prevalence of Borrelia (probably B. burgdorferi) in I. ricinus varied from 12.1% to 21.0%. No borreliae were found in H. concinna. Of the examined D. reticulatus from one site (n = 97) 11.3% contained either B. burgdorferi or a related Borrelia. This may be the first finding of Borrelia in an Eurasian Dermacentor species.     

Variability of mitochondrial cytochrome oxidase first subunit gene (<Emphasis Type="Italic">COI</Emphasis>) fragments in several tick species of the marginatus group (Ixodidae,Amblyomminae, <Emphasis Type="Italic">Dermacentor</Emphasis>)

This paper analyses variability of the nucleotide sequence of the mitochondrial cytochrome oxidase first subunit gene fragments in four tick species of the marginatus group—Dermacentor marginatus, D. silvarum, D. niveus, and D. nuttalli. It is noted that, with the exception of D. niveus, the clustering of mitotypes in the marginatus group does not show a clear correspondence of the species identity of ticks, which had preliminarily been established based on morphological characters.     

The diversity of chloroplast microsatellite loci in Siberian fir (Abies sibirica Ledeb.) and two Far East fir species A. nephrolepis (Trautv.) Maxim. and A. sachalinensis Fr. Schmidt

The genetic variability in 29 populations of Abies sibirica, three of A. nephrolepis, and seven of A. sachalinensis was studied using SSR markers of chloroplast DNA. Stable amplification and polymorphic products were obtained using primer pairs Pt71936 and Pt30204 (with nine and forteen alleles, respectively) of 10 pairs. Totally, 70 haplotypes were found, 43 in A. sibirica, 49 in A. sachalinensis, and 31 in A. nephrolepis. The highest values of genetic diversity parameters were observed in A. sachalinensis, and the lowest in A. nephrolepis. The Siberian fir differs from Far East species by the uneven multimodal frequency distributions of allele length in both cpSSR loci, which is explained by the presence of few separated from each other dominating haplotypes. This fact indicates that A. sibirica and the Far East species have different demographic histories. In A. sibirica, the proportion of diversity between populations in the total genetic diversity, calculated taking into account the differences between haplotypes (R(ST)) was 8.34% and 4.42% without accounting for haplotypes differences (R(ST) > G(ST), P= 0.01). The pairwise G(ST) correlate significantly with geographic distances between the populations A. sibirica and with genetic distances D calculated from allozyme data. No such correlations were found with the R(ST) parameter. The results of cpSSR variability analysis strongly support the conclusions inferred from allozyme data: several geographic groups of comparatively genetically close populations are identified, which may be explained by the invasion of colonization of the present-day Siberian fir range.     

The meadow tick Dermacentor reticulatus in natural foci of tick-borne encephalitis in Udmurtia

In southern Udmurtia, where occur both Dermacentor reticulatus and Ixodes persulcatus, in the years of high abundance of small mammals feeding periods of larvae and nymphs of these ticks coincide completely. The duration of simultaneous parasitism of preimago of the above ixodid species on animals is of epidemiological significance as far as within this period the infection of young stages of D. reticulatus with the virus of tick-borne encephalitis occurs. This is confirmed by the isolation of I strain of the virus from D. reticulatus collected at the state of engorged nymphs on hosts common with I. persulcatus and moulted in the laboratory.