Ticks on game animals in the fragmented agricultural landscape of western Poland

Epidemiologic Survey of Crimean-Congo Hemorrhagic Fever Virus in Suids, Spain

We conducted a cross-sectional study in wild boar and extensively managed Iberian pig populations in a hotspot area of Crimean-Congo hemorrhagic fever virus (CCHFV) in Spain. We tested for antibodies against CCHFV by using 2 ELISAs in parallel. We assessed the presence of CCHFV RNA by means of reverse transcription quantitative PCR protocol, which detects all genotypes. A total of 113 (21.8%) of 518 suids sampled showed antibodies against CCHFV by ELISA. By species, 106 (39.7%) of 267 wild boars and 7 (2.8%) of 251 Iberian pigs analyzed were seropositive. Of the 231 Iberian pigs and 231 wild boars analyzed, none tested positive for CCHFV RNA. These findings indicate high CCHFV exposure in wild boar populations in endemic areas and confirm the susceptibility of extensively reared pigs to CCHFV, even though they may only play a limited role in the enzootic cycle.

Differential microbial composition in parasitic vs. questing ticks based on 16S next-generation sequencing

Introduction

As tick-borne diseases rise to become the second most prevalent arthropod-transmitted disease globally, the increasing investigations focus on ticks correspondingly. Factors contributed to this increase include anthropogenic influences, changes in vertebrate faunal composition, social-recreational shifts, and climatic variation. Employing the 16S gene sequence method in next-generation sequencing (NGS) allows comprehensive pathogen identification in samples, facilitating the development of refined approaches to tick research omnidirectionally.

Methods

In our survey, we compared the microbial richness and biological diversity of ticks in Wuwei City, Gansu province, differentiating between questing ticks found in grass and parasitic ticks collected from sheep based on 16S NGS method.

Results

The results show Rickettsia, Coxiella, and Francisella were detected in all 50 Dermacentor nuttalli samples, suggesting that the co-infection may be linked to specific symbiotic bacteria in ticks. Our findings reveal significant differences in the composition and diversity of microorganisms, with the Friedmanniella and Bordetella genera existing more prevalent in parasitic ticks than in questing ticks (p < 0.05). Additionally, the network analysis demonstrates that the interactions among bacterial genera can be either promotive or inhibitive in ticks exhibiting different lifestyles with the correlation index |r| > 0.6. For instance, Francisella restrains the development of 10 other bacteria in parasitic ticks, whereas Phyllobacterium and Arthrobacter enhance colonization across all tick species.

Discussion

By leveraging NGS techniques, our study reveals a high degree of species and phylogenetic diversity within the tick microbiome. It further highlights the potential to investigate the interplay between bacterial genera in both parasitic and questing ticks residing in identical habitat environments.

Molecular Survey and Spatial Distribution of Rickettsia spp. in Ticks Infesting Free-Ranging Wild Animals in Pakistan (2017–2021)

Rickettsia spp. associated with ticks infesting wild animals have been mostly neglected in several countries, including Pakistan. To address this knowledge gap, ticks were collected during 2017 to 2021 from wild animals including cats (Felis chaus), Indian hedgehogs (Paraechinus micropus), and wild boars (Sus scrofa). The collected ticks were morpho-molecularly identified and screened for the detection of Rickettsia spp. Morphologically identified ticks were categorized into four species of the genus Rhipicephalus: Rhipicephalus haemaphysaloides, Rh. turanicus, Rh. sanguineus sensu lato (s.l), and Rh. microplus. Among 53 wild animals examined, 31 were infested by 531 ticks, an overall prevalence of 58.4%. Adult female ticks were predominant (242 out of 513 ticks collected, corresponding to 46%) in comparison with males (172, 32%), nymphs (80, 15%) and larvae (37, 7%). The most prevalent tick species was Rh. turanicus (266, 50%), followed by Rh. microplus (123, 23%), Rh. sanguineus (106, 20%), and Rh. haemaphysaloides (36, 7%). Among the screened wild animals, wild boars were the most highly infested, with 268 ticks being collected from these animals (50.4%), followed by cats (145, 27.3%) and hedgehogs (118, 22.3%). Tick species Rh. haemaphysaloides, Rh. turanicus, and Rh. sanguineus were found on wild boars, Rh. haemaphysaloides, and Rh. microplus on cats, and Rh. turanicus on hedgehogs. In a phylogenetic analysis, mitochondrial cytochrome C oxidase 1 (cox1) sequences obtained from a subsample (120) of the collected ticks clustered with sequences from Bangladesh, China, India, Iran, Myanmar, and Pakistan, while 16S ribosomal DNA (16S rDNA) sequences clustered with sequences reported from Afghanistan, Egypt, India, Pakistan, Romania, Serbia, and Taiwan. Among Rickettsia infected ticks (10/120, 8.3%), Rh. turanicus (7/10, 70%), and Rh. haemaphysaloides (3/10, 30%) were found infesting wild boars in the districts Mardan and Charsadda. The obtained rickettsial gltA gene sequences showed 99% and ompA gene sequences showed 100% identity with Rickettsia massiliae, and the phylogenetic tree shows ompA clustered with the same species reported from France, Greece, Spain, and USA. This study emphasizes the need for effective surveillance and control programs in the region to prevent health risks due to tick-borne pathogens, and that healthy infested wild animals may play a role in the spread of these parasites.

Changes in the occurrence range of hosts cause the expansion of the ornate dog tick Dermacentor reticulatus (Fabricius, 1794) in Poland

The turn of the twentieth and twenty-first centuries brought changes in the range of many pathogens and their vectors. An example is the Dermacentor reticulatus tick. So far, relatively not numerous, their range of occurrence was divided into two areas—western European and eastern. An increase in the number and spread of this tick has been observed since the 1990s. Possible causes may be changes in the average summer and winter temperature in Europe and changes in the structure and use of agricultural land and forest areas. Changes in the distribution and abundance of mammals which are the main hosts of adult ticks, such as elk Alces alces, red deer Cervus elaphus, raccoon dog Nyctereutes procyonoides and the red fox Vulpes vulpes, may be important factors as well. Increase in the size of the hosts populations correlates with the subsequent increase in numbers and the emergence of new tick populations. The food base of adult ornate dog ticks is a large herbivorous mammal population. Predatory mammals can support the expansion of the ticks. The expansion of the raccoon dog in the west correlates with the emergence of new D. reticulatus populations west to the previous border of the eastern range of their occurrence. The intrusion of foxes into inhabited areas may be a synanthropic factor that supports the rise of new tick populations in urban agglomerations.

Occurrence of juvenile Dermacentor reticulatus ticks in three regions in Poland: the final evidence of the conquest

Background

Two populations of Dermacentor reticulatus ticks (Western and Eastern) in Poland are among the most dynamic tick populations in Central Europe. Expansion and settlement of ticks in new localizations depend on the presence of suitable hosts, for both adult and juvenile ticks.

Methods

The current study was planned to complement our previous studies on questing adult ticks and was focused on a collection of juvenile D. reticulatus ticks from rodents from three regions in Poland, defined by the presence/absence of adult ticks (regions of the Western and Eastern tick population and the gap area between them) to confirm the existence of stable populations. Rodent trapping was conducted in open habitats (fallow lands, wasteland and submerged meadows) in 2016–2018 in June, July and/or August to encompass seasonal peaks of larvae and nymph activity.

Results

Altogether, three tick species were collected, 2866 D. reticulatus, 2141 Ixodes ricinus and 427 Haemaphysalis concinna. Dermacentor reticulatus was the most common (72.3%) and abundant (mean 17.94 ± 2.62 ticks/rodent) tick species on rodents from the Eastern region; in the Western region infestation of rodents was only 6.8%. Ixodes ricinus was found in all three regions and was the only tick species collected from rodents from the gap area. Haemaphysalis concinna was noted only in the Western region. The highest infestation of juvenile D. reticulatus was recorded on voles (Myodes and Microtus spp.), infestation of I. ricinus was the highest on Apodemus mice, and the majority of H. concinna ticks were collected from root voles Alexandromys oeconomus.

Conclusions

Our study confirmed a stable population of D. reticulatus in Eastern and Central Poland and a lower prevalence and mean abundance of this tick species among rodents from the Western region. A lack of juvenile D. reticulatus on rodents in Niewiadów confirmed the existence of the gap area, free of D. reticulatus ticks.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-05039-z.