Identification of Two Genotypes of Argas persicus and Associated Rickettsia-Specific Genes from Different Regions of Inner Mongolia.

Ticks are important vectors and reservoirs of several zoonotic pathogens. Recently, both known and unknown tick-borne pathogens have emerged and re-emerged, causing unpredictable epidemics. In this study, 211 soft tick samples were collected from Tongliao and Alxa in Inner Mongolia, China. Tick species were identified by morphological and molecular biological analyses. Morphological analysis showed that there was no significant difference in surface features between ticks from the 2 areas. Cloning by polymerase chain reaction (PCR) and sequencing of the 16S rRNA gene showed that all ticks belonged to the species Argas persicus. Analysis using Genetyx software indicated that there was a limited degree of diversity between ticks from the 2 areas. Three base changes were detected in the 16S rRNA gene. We constructed phylogenetic trees using MEGA 6.0 software and showed that the ticks from the 2 areas might have evolved independently from species in other geographical areas. To assess the presence of Rickettsia, Streptococcus suis, and Staphylococcus aureus pathogens in tick samples, over 100 16S rRNA sequences belonging to these 3 pathogens were obtained from GenBank. We used CLC Sequence Viewer 7.0 to determine conserved sequences for the design of degenerate primers. Using standard PCR, we detected Rickettsia-specific genes, including 16S rRNA, 17KD, and ompB, in gDNA samples of ticks from Alxa. This study has laid a foundation for future studies on the biodiversity of ticks and for a new pathogen information database of ticks in local areas.

Notes on maternal behaviour in soft ticks: Specifically observed in Argas (Argas) striatus Bedford, 1932 and Argas (Secretargas) transgariepinus White, 1846.

Maternal behaviour (carrying of larvae on the opisthosoma) in ticks has thus far only been observed in Antricola (Parantricola) marginatus and was considered a unique derived adaptation of this genus. The authors extend this observation to two additional argasid species, namely Argas (Argas) striatus and Argas (Secretargas) transgariepinus. In addition, brooding behaviour over eggs were observed with A. (S.) transgariepinus. Maternal behaviour may be an evolutionary adaptation to ecological challenges in habitats unsuited for larval survival and may be related to the presence of pulvilli in larvae. This adaptation might have been present in the ancestral tick lineage since pulvilli occur in all tick families, and may have been derived from a more ancient adaptation in chelicerates where maternal behaviour was common. Female A. (S.) transgariepinus also possess a unique area on their ventral abdomen that is absent in males and may be a unique adaptation for maternal behaviour in this species. Phylogenetic analysis of the 16S rRNA genes for both species indicate that they are unique lineages that group basal to other members of the Argas genus, supporting the possibility that they harbour ancestral traits for this group.

Mitochondrial gene heterogeneity of the bat soft tick Argas vespertilionis (Ixodida: Argasidae) in the Palaearctic.

BACKGROUND: Recently, a high degree of mitochondrial gene heterogeneity was demonstrated between conspecific ixodid ticks of bats in Eurasia. Argas vespertilionis is a soft tick species of mainly vespertilionid bats, also with a wide distribution in the Old World. The aim of this study was to investigate the morphology, mitochondrial gene heterogeneity and host range of A. vespertilionis in the Old World. RESULTS: Altogether 318 soft tick larvae were collected from 17 bat species (belonging to six genera) in seven countries. Based on the general morphology (setal arrangement) of 314 A. vespertilionis larvae, and the detailed measurements of fifteen larvae, only minor morphological differences (in dorsal plate size and the type of serrate setae) were observed between specimens from Europe and Vietnam. On the other hand, cytochrome c oxidase subunit 1 (cox1) and 16S rRNA gene sequence analyses of 17 specimens showed that A. vespertilionis from Europe is genetically different (with up to 7.5% cox1 and 5.7% 16S rRNA gene sequence divergence) from specimens collected in Vietnam, and their phylogenetic separation is well supported. CONCLUSION: In its evaluated geographical range, no larval phenotypic differences justify the existence of separate species under the name A. vespertilionis. However, phylogenetic analyses based on two mitochondrial markers suggest that it represents a complex of at least two putative cryptic species. The broad host range of A. vespertilionis might partly explain its lower degree of mitochondrial gene heterogeneity in comparison with ixodid bat tick species over the same geographical region of Eurasia.

Borrelia, Rickettsia, and Ehrlichia species in bat ticks, France, 2010.

Argas vespertilionis, an argasid tick associated with bats and bat habitats in Europe, Africa, and Asia has been reported to bite humans; however, studies investigating the presence of vector-borne pathogens in these ticks are lacking. Using molecular tools, we tested 5 A. vespertilionis ticks collected in 2010 from the floor of a bat-infested attic in southwestern France that had been converted into bedrooms. Rickettsia sp. AvBat, a new genotype of spotted fever group rickettsiae, was detected and cultivated from 3 of the 5 ticks. A new species of the Ehrlichia canis group, Ehrlichia sp. AvBat, was also detected in 3 ticks. Four ticks were infected with Borrelia sp. CPB1, a relapsing fever agent of the Borrelia group that caused fatal borreliosis in a bat in the United Kingdom. Further studies are needed to characterize these new agents and determine if the A. vespertilionis tick is a vector and/or reservoir of these agents.

The new locality of Argas reflexus Fabricius, 1794 in Warsaw, Poland.

The new locality of Argas reflexus in Warsaw, Poland is recorded. The ticks occur in the lof of apartment blocks, inhabited by pigeons. When the birds were removed by cleaning services, the ticks began to look for a new host and penetrate the flats. Some of the lodgers had been bitten by tick larvae and nymphs.

Impact of ivermectin on the ultrastructure of the testis of Argas (Persicargas) persicus (Ixodoidea: Argasidae).

Mated male Argas persicus were dissected 1 and 2 weeks after feeding on untreated and ivermectin (IVM)-treated pigeons. One week after feeding, testes of untreated ticks were filled with rounded spermatids with subplasmalemmal vesicles and cytoplasmic organelles, but lacking in treated ticks. Two weeks after feeding, testes were crowded with elongated spermatozoa supported by double-walled cisternal tubes. The tubes consisted of two opposite walls, each with outer-fringed processes and inner elongated cisternae. Both were supported with electron dense striated plates in the middle of the spermatozoon. Internally, the cisternal tubes contained mitochondria and vacuoles. The nuclei were elongated dense masses between the tubes and the cell membranes. Subcutaneous inoculation of IVM at the dose 400 microg/kg pigeon resulted in extensive alterations in the testis of A. persicus. IVM prevented the development of new spermatids. There was a break down of cell membranes and cytoplasmic organelles of spermatozoa. Multivesicular bodies and numerous vacuoles were noticed in their cytoplasm. Double membranes of elongated cisternae and striation of electron dense plates became indistinct. IVM caused granulation and vacuolization of the nucleus as well as injury of mitochondrial cristae. The results suggest that IVM may bind to the neurotransmitter or the hormone involved in the process of sperm development or may be toxic to the germinal cells of A. persicus testis.

[The pigeon tick, Argas reflexus, and hazard for human health]. / La zecca del piccione Argas reflexus (Acari: Argasidae) ed i rischi per la salute umana.

The massive presence of the pigeon (Columba livia f. domestica) in urban areas not only is cause of serious aesthetic damages as decline of squares, of churches, of statues and buildings, but often creates many hygienic and medical problems. The pigeon, in fact, can transmit a great number of pathogenic agents and also be infested by several ectoparasites. Among these, Argas reflexus (Acari: Argasidae), the well known pigeon tick, is the most important ectoparasite that can involve also human health. Buildings infested by A. reflexus and attacks by this tick species to man are frequently reported, with an increasing interest for human health. In fact the pigeon tick bites can induce anaphylactic reactions for the presence of allergens, and as vector, the tick can also transmit some pathogens. This review deals with actual knowledge on the distribution, eco-biology, vector competence, prevention and control of A. reflexus in Italy.

[Morphology of tick tarsus (Acari: Ixodida)--modifications connected with life cycle, behaviour, and habitat]. / Budowa stóp kleszczy (Acari: Ixodida)--modyfikacje Zwiazane z cyklem zyciowym, behawiorem i siedliskiem.

Ticks are ectoparasites of wide variety of vertebrates living in various types of environment all over the world. Morphological, biological, and physiological differences among tick species as well as among tick life stages are the result of tick adaptations to various life conditions. This paper presents morphological adaptations of tick tarsus to the hosts and the life conditions. The authors underline morphological differences of Haller's organ and pretarsus in four tick species: Argas reflexus (Fabricius, 1794), A. persicus (Oken, 1818), Dermacentor reticulatus (Fabricius, 1794), and Ixodes ricinus (Linnaeus, 1758).

Morphology and structural organization of Gene's organ in Argas walkerae.

Electron microscopy revealed that Gene's organ in females of Argas walkerae Kaiser & Hoogstraal (Ixodida: Argasidae) is formed as a double-sac structure consisting of an outer epithelial and an inner cuticular sac. The latter emerges through the camerostomal aperture to the exterior in ovipositing ticks. The epithelial sac forms the corpus and the two blind-ending horns, which pass into the epithelium of the excretory duct of a gland at each side of Gene's organ and envelop the cuticular sac. Both excretory ducts open into the lumen between the epithelial and the cuticular sac. The cuticular sac is folded and consists of a fibrous endocuticula outwards towards the lumen between the epithelial and the cuticular sac and of a smooth epicuticula inwards. Parallel running grooves occur over the lateral epicuticular surface turning medially into cobble-stone pavement-like rises. Tubuli pass through the cuticular sac ending in pores on the epicuticular surface and open into the lumen between the epithelial and the cuticular sac. Muscle fibres pass through the epithelial sac at the horn tips and are inserted to the cuticular sac. In ovipositing females, the glands are fully developed and the lumen between the epithelial and the cuticular sac is filled with an amorphous mass.