Nuclear (18S-28S rRNA) and mitochondrial genome markers of Carios (Carios) vespertilionis (Argasidae) support Carios Latreille, 1796 as a lineage embedded in the Ornithodorinae: re-classification of the Carios sensu Klompen and Oliver (1993) clade into its respective subgenera.

Argasid systematics remains controversial with widespread adherence to the Hoogstraal (1985) classification scheme, even though it does not reflect evolutionary relationships and results in paraphyly for the main genera of soft ticks (Argasidae), namely Argas and Ornithodoros. The alternative classification scheme, proposed by Klompen and Oliver (1993), has problems of its own: most notably paraphyly of the subgenus Pavlovskyella and the controversial grouping together of the subgenera Alectorobius, Antricola, Carios, Chiropterargas, Nothoaspis, Parantricola, Reticulinasus and Subparmatus into the genus Carios. Recent phylogenetic analyses of 18S/28S rRNA sequences and mitochondrial genomes agree with the scheme of Klompen and Oliver (1993), with regard to the paraphyly of Pavlovskyella, placement of Alveonasus, Ogadenus, Proknekalia and Secretargas in the Argasinae and placement of Carios and Chiropterargas in the Ornithodorinae (Mans et al., 2019). The Carios clade and its constituent subgenera remain controversial, since the phylogenetic position of its type species Carios (Carios) vespertilionis Latreille, 1796 (formerly Argas vespertilionis) has not been determined with confidence. The current study aimed to resolve Carios sensu lato Klompen and Oliver, 1993, and Carios sensu stricto Hoogstraal, 1985, by determining and analysing phylogenetic nuclear and mitochondrial markers for C. (C.) vespertilionis. Both the nuclear and mitochondrial markers support placement of Carios s.s. within the subfamily Ornithodorinae, but to the exclusion of the clade that includes the 6 other subgenera that are part of Carios s.l. Klompen and Oliver (1993), namely Alectorobius, Antricola, Nothoaspis, Parantricola, Reticulinasus and Subparmatus. These 6 subgenera form a monophyletic clade that might be placed as new subgenera within the genus Alectorobius, or elevated to genera. Given the substantial differences in biology among these subgenera, we propose that these 6 subgenera be elevated to genera. Thus, we propose to modify the classification scheme of Mans et al. (2019) so that the subfamily Argasinae now has six genera, Alveonasus, Argas (subgenera Argas and Persicargas), Navis, Ogadenus, Proknekalia and Secretargas, and the subfamily Ornithodorinae has nine genera, Alectorobius, Antricola (subgenera Antricola and Parantricola), Carios, Chiropterargas, Nothoaspis, Ornithodoros (subgenera Microargas, Ornamentum, Ornithodoros, Pavlovskyella and Theriodoros), Otobius, Reticulinasus and Subparmatus (genera indicated in bold).

Microbial diversity in the tick Argas japonicus (Acari: Argasidae) with a focus on Rickettsia pathogens.

The soft tick Argas japonicus mainly infests birds and can cause human dermatitis; however, no pathogen has been identified from this tick species in China. In the present study, the microbiota in A. japonicus collected from an epidemic community was explored, and some putative Rickettsia pathogens were further characterized. The results obtained indicated that bacteria in A. japonicus were mainly ascribed to the phyla Proteobacteria, Firmicutes and Actinobacteria. At the genus level, the male A. japonicus harboured more diverse bacteria than the females and nymphs. The bacteria Alcaligenes, Pseudomonas, Rickettsia and Staphylococcus were common in nymphs and adults. The abundance of bacteria belonging to the Rickettsia genus in females and males was 7.27% and 10.42%, respectively. Furthermore, the 16S rRNA gene of Rickettsia was amplified and sequenced, and phylogenetic analysis revealed that 13 sequences were clustered with the spotted fever group rickettsiae (Rickettsia heilongjiangensis and Rickettsia japonica) and three were clustered with Rickettsia limoniae, which suggested that the characterized Rickettsia in A. japonicus were novel putative pathogens and also that the residents were at considerable risk for infection by tick-borne pathogens.

Skin lesions in humans bitten by European pigeon tick Argas reflexus (Fab.) (Ixodida: Argasidae) massively occurring in the Upper Silesian conurbation of south-west Poland.

INTRODUCTION AND OBJECTIVE: The great number of pigeon populations in many European cities promotes the spread of the European pigeon tick (Argas reflexus), the bites of which cause local and systemic reactions. The aim was to study the occurrence of A. reflexus in several cities of Upper Silesia, and skin lesions caused by A. reflexus tick bites in humans. MATERIAL AND METHODS: The results of investigations carried out in 1995-2002 in five cities located in the Upper Silesian conurbation are presented. Specimens of A. reflexus were collected for one hour in attics and lofts inhabited by these ticks. A history of skin lesions caused by bites was taken from residents who had been infested by A. reflexus. The development of skin lesions was monitored for three months in two individuals who had been bitten several times by these arthropods. RESULTS: In the localities, 987 A. reflexus specimens were collected, including 334 females, 269 males, and 384 various nymphal stages. Within one hour, 38-109 ticks specimens were collected at the study sites. Cases of attacks by unengorged A. reflexus were reported in all the habitats located in the residential buildings; the ticks were also found in residents' flats and in staircases. Residents who had been repeatedly attacked by European pigeon ticks developed a strong inflammatory reaction to the components of tick saliva, and had purple papules with necrosis in the centre of the lesion. The tick bite areas exhibited scars and hyperpigmentation. CONCLUSIONS: Individuals attacked by A. reflexus several times are at risk of development of severe persistent local reactions to bites. Pigeon ticks, trophically associated with pigeons present abundantly in the Upper Silesian conurbation and other European urban habitats, pose a serious threat to public health.

Host finding of the pigeon tick Argas reflexus.

The medically and veterinary important feral pigeon tick Argas reflexus (Ixodida: Argasidae) Fabricius usually feeds on pigeons, but if its natural hosts are not available, it also enters dwellings to bite humans that can possibly react with severe allergic reactions. Argas reflexus is ecologically extremely successful as a result of some outstanding morphological, physiological, and ethological features. Yet, it is still unknown how the pigeon tick finds its hosts. Here, different host stimuli such as living nestlings as well as begging calls, body heat, smell, host breath and tick faeces, were tested under controlled laboratory conditions. Of all stimuli tested, only heat played a role in host-finding. The heat stimulus was then tested under natural conditions within a pigeon loft. The results showed that A. reflexus is able to find a host over short distances of only a few centimetres. Furthermore, it finds its host by random movements and recognizes a host only right before direct contact is made. The findings are useful for the control of A. reflexus in infested apartments, both to diagnose an infestation and to perform a success monitoring after disinfestation.

The influence of the fasting period on the number of nymphal instars and on the sex ratio of Argas (Persicargas) miniatus (Acari: Argasidae).

The current study investigated the biology of nymphs of the first and second instars of Argas (Persicargas) miniatus. Nymphs were deprived of food for 15, 30 or 60 days and held at 27 ± 1 °C and 80 ± 10% relative humidity (controlled conditions) or at room conditions of temperature and relative humidity. Nymphs of first instar deprived of food for 15 or 30 days molted to second and third instars in both controlled and room conditions. Nymphs of the first instar deprived of food for 60 days had 28 and 37% mortality in controlled and room conditions, respectively; and survivors did not attach to the host. Nymphs of the second instar, deprived of food for 60 days, molted either to the third instar or to males after feeding on Gallus gallus, and the nymphs of the third instar developed to adults (42.42% males and 36.36% females when nymphs were held in controlled temperature and humidity conditions, and 40.54% males and 48.65% females when nymphs were held in room conditions). The remainder of the nymphs molted to the fourth instar and then molted to females. In conclusion, the nymphal starvation period of 60 days determined the number of nymph instars in the life cycle of A. miniatus under the experimental conditions studied.

The influence of the fasting period on the number of nymphal instars and on the sex ratio of Argas (Persicargas) miniatus (Acari: Argasidae) / Influência do período de jejum no número de instares ninfais e na razão sexual de Argas (Persicargas) miniatus (Acari: Argasidae)

The current study investigated the biology of nymphs of the first and second instars of Argas (Persicargas) miniatus. Nymphs were deprived of food for 15, 30 or 60 days and held at 27 ± 1 ºC and 80 ± 10 percent relative humidity (controlled conditions) or at room conditions of temperature and relative humidity. Nymphs of first instar deprived of food for 15 or 30 days molted to second and third instars in both controlled and room conditions. Nymphs of the first instar deprived of food for 60 days had 28 and 37 percent mortality in controlled and room conditions, respectively; and survivors did not attach to the host. Nymphs of the second instar, deprived of food for 60 days, molted either to the third instar or to males after feeding on Gallus gallus, and the nymphs of the third instar developed to adults (42.42 percent males and 36.36 percent females when nymphs were held in controlled temperature and humidity conditions, and 40.54 percent males and 48.65 percent females when nymphs were held in room conditions). The remainder of the nymphs molted to the fourth instar and then molted to females. In conclusion, the nymphal starvation period of 60 days determined the number of nymph instars in the life cycle of A. miniatus under the experimental conditions studied.

Os aspectos biológicos de ninfas de primeiro e segundo instares de Argas (Persicargas) miniatus quando submetidas a diferentes períodos de jejum (15, 30 e 60 dias), foram estudados em estufa climatizada (27 ± 1 ºC e 80 ± 10 por cento de umidade relativa) e em ambiente de laboratório. Ninfas de primeiro instar que foram submetidas a um período de jejum de 15 e 30 dias mudaram para ninfas de segundo e terceiro instar, em ambas as condições estudadas. No período de 60 dias de jejum verificou-se mortalidade de 28 e 37 por cento das ninfas de primeiro instar, em estufa climatizada e em ambiente de laboratório, respectivamente. As ninfas sobreviventes não se fixaram sobre os hospedeiros. As ninfas de segundo instar, após 60 dias de jejum, desenvolveram-se em ninfas de terceiro instar ou machos, quando alimentadas em Gallus gallus. Ainda neste grupo, as ninfas de terceiro instar mudaram para adultos (42,42 e 40,54 por cento machos; 36,36 e 48,65 por cento fêmeas, nas condições ambiente de laboratório e estufa climatizada, respectivamente) e o restante desenvolveu-se em ninfas de quarto instar que por sua vez mudaram para fêmeas. Então, a situação de jejum (60 dias) em que as ninfas foram submetidas determinou o número de ninfas no ciclo biológico de A. miniatus, sob as condições experimentais estudadas.

The fowl tick, Argas (Persicargas) persicus (Ixodoidea: Argasidae): description of the egg and redescription of the larva by scanning electron microscopy.

This scanning electron microscopy study revealed that the egg of Argas persicus was covered with chorion which appeared as a wrinkled layer containing regions of three textures. The first had elevated parts of slightly rough surface. The second had irregular smooth elevations; each carried numerous parallel horizontal foldings with vertical ridges. The last region had rough surface with irregularly shaped projections. Following the removal of the chorion, shell was observed to have one polar micropyle and numerous slit like openings. Length (L), width (W) and L/W ratio of the egg were measured. Investigation of larvae revealed extensively folded integument of idiosoma and spherical or elongated tubercles on dorsal plate. Mouth enclosed between ventral hypostome and two dorsal chelicerae. Hypostome carried four longitudinal rows of conical denticles. Each chelicera was made up of two segments; the basal one appeared as a pocket for the distal one. Haller's organ consisted of an anterior pit containing seven sensilla and a posterior capsule with four apertures. Distribution of chemo- and mechano-sensilla on the body was examined. Measurements of whole body, idiosoma, dorsal plate, capitulum, hypostome, palp and different types of sensilla both on the body and Haller's organ are also presented.

Acaricidal efficacy of Myrrh (Commiphora molmol) on the fowl tick Argas persicus (Acari: Argasidae).

Five concentrations of purified extract of Myrrh from Commiphora molmol tree were prepared to study its effects on the fowl tick Argas persicus under laboratory conditions. The results revealed that Myrrh had dependant dose toxic effect on the adult female of A. persicus. Toxicity increased gradually daily post treatment. The LC50 was 1.28%, 0.88%, 0.84%, 0.50% and 0.42% at Ist, 2nd, 3rd, 6th and 12th days respectively. At 12th day, the recorded mortality rates were 63, 67, 76, 87 and 94% for concentrations, 0.625, 1.25, 2.5, 5 and 10%, respectively against 5% in control. Histopathological and Transmission election microscope (TEM) examinations showed the lysing of epithelial gut cells in treated groups. The lysed epithelial gut cells showed irregularly distributed nucleus, commonly at low concentrations and rarely in high concentrations of Myrrh. The lysed epithelial gut cells, without nucleus or with aggregated one beside the basal lamina, were common at high concentrations and rare in low concentrations of Myrrh. Consequently, Myrrh can rapidly penetrate the cuticle to body cavity, destroy the epithelial gut cells and finally cause the death of ticks.