First molecular detection of Francisella-like endosymbionts in Hyalomma and Rhipicephalus tick species collected from vertebrate hosts from Sardinia island, Italy

Emerging Hyalomma lusitanicum: From identification to vectorial role and integrated control

In the Mediterranean basin, the tick species Hyalomma lusitanicum Koch stands out among other species of the Hyalomma genus due to its wide distribution, and there is great concern about its potential role as a vector and/or reservoir and its continuous expansion to new areas because of climate warming and human and other animal movements. This review aims to consolidate all the information on H. lusitanicum, including taxonomy and evolution, morphological and molecular identification, life cycle, sampling methods, rearing under laboratory conditions, ecology, hosts, geographical distribution, seasonality, vector role and control methods. The availability of adequate data is extremely relevant to the development of appropriate control strategies in areas where this tick is currently distributed as well as in new areas where it could become established in the near future.

Environmental determinants of the occurrence and activity of Ixodes ricinus ticks and the prevalence of tick-borne diseases in eastern Poland

Ixodes ricinus is the most widely distributed tick species in Europe. Mainly deciduous and mixed forests, pastures, and urban parks are habitats preferred by this species. I. ricinus ticks are also one of the most important reservoirs and vectors of human and animal infectious diseases on the continent. Borrelia burgdorferi s.l. spirochetes causing Lyme borreliosis (LB) in humans and tick borne encephalitis virus (TBEV), which is a causative agent of tick-borne encephalitis (TBE), are pathogens with the highest medical importance transmitted by this species. Investigations of the environmental determinants of the occurrence and activity of I. ricinus are crucial for elucidation of the environmental background of tick-borne diseases. In eastern Poland, I. ricinus is a common species with peak activity recorded in May in the entire region. During this period, 49 females, 32 males, and 55 I. ricinus nymphs were collected from an area of 900 m². The results of the present study show that the occurrence and seasonal activity of this tick species are mainly influenced by microhabitat conditions, and saturation deficit has a significant effect on the activity of the species. Eastern Poland is characterized by a high incidence of LB and TBE. We have shown a correlation between the forest cover and the number of reported cases of tick-borne diseases.

Microbial community of Hyalomma lusitanicum is dominated by Francisella-like endosymbiont

Exploring tick associations with complex microbial communities and single-microbial partners, especially intracellular symbionts, has become crucial to understand tick biology. Of particular interest are the underlying interactions with biological consequences i.e. tick fitness, vector competence. In this study, we first sequenced the 16S rRNA bacterial phylogenetic marker in adult male ticks of Hyalomma lusitanicum collected from 5 locations in the province of Cáceres to explore the composition of its microbial community. Overall, 16S rRNA sequencing results demonstrated that the microbial community of H. lusitanicum is mostly dominated by Francisella-like endosymbionts (FLEs) (ranging from 52% to 99% of relative abundance) suggesting it is a key taxon within the microbial community and likely a primary endosymbiont. However, further research is required to explore the mechanisms underlying the interaction between FLEs and H. lusitanicum.

Ticks (Acari: Ixodidae) on birds migrating to the island of Ponza, Italy, and the tick-borne pathogens they carry

Seasonal migration of birds between breeding and wintering areas can facilitate the spread of tick species and tick-borne diseases. In this study, 151 birds representing 10 different bird species were captured on Ponza Island, an important migratory stopover off the western coast of Italy and screened for tick infestation. Ticks were collected and identified morphologically. Morphological identification was supported through sequencing a fragment of the 16S mitochondrial gene. In total, 16 captured birds carried ticks from four tick species: Hyalomma rufipes (n = 14), Amblyomma variegatum (n = 1), Amblyomma sp. (n = 1), and Ixodes ventalloi (n = 2). All specimens were either larvae (n = 2) or nymphs (n = 16). All ticks were investigated for tick-borne pathogens using published molecular methods. Rickettsia aeschlimannii was detected in six of the 14 collected H. rufipes ticks. Additionally, the singular A. variegatum nymph tested positive for R. africae. In all 14 H. rufipes specimens (2 larvae and 12 nymphs), Francisella-like endosymbionts were detected. Four H. rufipes ticks tested positive for Borrelia burgdorferi sensu lato in a screening PCR but did not produce sufficient amplicon amounts for species identification. All ticks tested negative for tick-borne encephalitis virus, Crimean-Congo hemorrhagic fever virus, Coxiella burnetii, Coxiella-like organisms, Babesia spp., and Theileria spp. This study confirms the role of migratory birds in the spread and establishment of both exotic tick species and tick-borne pathogens outside their endemic range.