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Tick microbiota can be targeted for the control of tick-borne diseases such as human granulocytic anaplasmosis (HGA) caused by model pathogen, Anaplasma phagocytophilum. Frankenbacteriosis is inspired by Frankenstein and defined here as paratransgenesis of tick symbiotic/commensal bacteria to mimic and compete with tick-borne pathogens. Interactions between A. phagocytophilum and symbiotic Sphingomonas identified by metaproteomics analysis in Ixodes scapularis midgut showed competition between both bacteria. Consequently, Sphingomonas was selected for frankenbacteriosis for the control of A. phagocytophilum infection and transmission. The results showed that Franken Sphingomonas producing A. phagocytophilum major surface protein 4 (MSP4) mimic pathogen and reduce infection in ticks by competition and interaction with cell receptor components of infection. Franken Sphingomonas-MSP4 transovarial and trans-stadial transmission suggests that tick larvae with genetically modified Franken Sphingomonas-MSP4 could be produced in the laboratory and released in the field to compete and replace the wildtype populations with associated reduction in pathogen infection/transmission and HGA disease risks.

Constraints in the characterization of microbiota community that circulates in the host have limited the extent of co-infection studies in natural populations. In this study, we used a metaproteomics approach to characterize the mandibular lymph nodes microbiota of wild boar (Sus scrofa) naturally exposed to an increasing trend of Mycobacterium tuberculosis complex (MTC) infection. Our results showed a reduction in microbiota diversity and changes in the composition, structure and functionality of the microbiota community associated with an increase in tuberculosis prevalence, from 45% in 2002/06 to 83% in 2009/12. These temporal changes were accompanied by an increase in the relative abundance of Babesia, Theileria and Pestivirus genera and a decrease in the Ascogregarina and Chlorella. A positive association was also evidenced between the prevalence of tuberculosis and the presence of microbial proteins responsible for carbohydrate transport and metabolism. Our findings suggest MTC-host-microbiota interactions at the population level, which may occur in order to ensure sufficient metabolic resources for MTC survival, growth and transmission. We strongly recommend the use of metaproteomics when studying microbiota communities in wildlife populations, for which traditional diagnostic techniques are limited and in which new organisms with a pathogenic potential for domestic animals and humans may appear.

Exploring the microbial diversity of ticks is crucial to understand geographical dispersion and pathogen transmission. Tick microbes participate in many biological processes implicated in the acquisition, maintenance, and transmission of pathogens, and actively promote host phenotypic changes, and adaptation to new environments. The microbial community of Ixodes ventalloi still remains unexplored. In this study, the bacterial microbiota of wild-caught I. ventalloi was characterized using shotgun-metagenomic sequencing in samples from unfed adults collected during December 2013-January 2014 in two locations from Sicily, Italy. The microbiota identified in I. ventalloi was mainly composed of symbiotic, commensal, and environmental bacteria. Interestingly, we identified the genera Anaplasma and Borrelia as members of the microbiota of I. ventalloi. These results advance our information on I. ventalloi microbiota composition, with potential implications in tick-host adaptation, geographic expansion, and vector competence.

Biting midges of the genus Culicoides are known vectors of arboviruses affecting human and animal health. However, little is known about Culicoides imicola microbiota and its influence on this insect’s biology. In this study, the impact of biotic and abiotic factors on C. imicola microbiota was characterized using shotgun-metagenomic sequencing of whole-body DNA samples. Wild-caught C. imicola adult nulliparous females were sampled in two locations from Sicily, Italy. The climatic variables of temperature and soil moisture from both localities were recorded together with potential host bloodmeal sources. Shared core microbiome among C. imicola populations included Pseudomonas, Escherichia, Halomonas, Candidatus Zinderia, Propionibacterium, and Schizosaccharomyces. Specific and unique taxa were also found in C. imicola from each location, highlighting similarities and differences in microbiome composition between the two populations. DNA and protein identification showed differences in host preferences between the two populations, with Homo sapiens and Canis lupus familiaris L. being the preferred bloodmeal source in both locations. A principal component analysis showed that the combined effect of host preferences (H. sapiens) and local soil moisture factors shape the microbiome composition of wild-caught populations of C. imicola. These results contribute to characterizing the role of the microbiome in insect adaptation and its utility in predicting geographic expansion of Culicoides species with potential implications for the control of vector-borne diseases.

Here, we report the draft genome sequences of isolates of Anaplasma phagocytophilum, Anaplasma marginale, and Anaplasma ovis. The genomes of A. phagocytophilum (human), A. marginale (cattle), and A. ovis (goat) isolates from the United States were sequenced and characterized. This is the first report of an A. ovis genome sequence.

An innovative metaomics approach integrating metatranscriptomics and metaproteomics was used to characterize bacterial communities in the microbiota of the Lyme borreliosis spirochete vector, Ixodes ricinus (Acari: Ixodidae). Whole internal tissues and salivary glands from unfed larvae and female ticks, respectively were used. Reused I. ricinus RNA-sequencing data for metranscriptomics analysis together with metaproteomics provided a better characterization of tick bacterial microbiota by increasing bacteria identification and support for identified bacteria with putative functional implications. The results showed the presence of symbiotic, commensal, soil, environmental, and pathogenic bacteria in the I. ricinus microbiota, including previously unrecognized commensal and soil microorganisms. The results of the metaomics approach may have implications in the characterization of putative mechanisms by which pathogen infection manipulates tick microbiota to facilitate infection. Metaomics approaches integrating different omics datasets would provide a better description of tick microbiota compositions, and insights into tick interactions with microbiota, pathogens and hosts.

Ticks are among the most important vectors of pathogens affecting humans and other animals worldwide. They do not only carry pathogens however, as a diverse group of commensal and symbiotic microorganisms are also present in ticks. Unlike pathogens, their biology and their effect on ticks remain largely unexplored, and are in fact often neglected. Nonetheless, they can confer multiple detrimental, neutral, or beneficial effects to their tick hosts, and can play various roles in fitness, nutritional adaptation, development, reproduction, defense against environmental stress, and immunity. Non-pathogenic microorganisms may also play a role in driving transmission of tick-borne pathogens (TBP), with many potential implications for both human and animal health. In addition, the genetic proximity of some pathogens to mutualistic symbionts hosted by ticks is evident when studying phylogenies of several bacterial genera. The best examples are found within members of the Rickettsia, Francisella, and Coxiella genera: while in medical and veterinary research these bacteria are traditionally recognized as highly virulent vertebrate pathogens, it is now clear to evolutionary ecologists that many (if not most) Coxiella, Francisella, and Rickettsia bacteria are actually non-pathogenic microorganisms exhibiting alternative lifestyles as mutualistic ticks symbionts. Consequently, ticks represent a compelling yet challenging system in which to study microbiomes and microbial interactions, and to investigate the composition, functional, and ecological implications of bacterial communities. Ultimately, deciphering the relationships between tick microorganisms as well as tick symbiont interactions will garner invaluable information, which may aid in the future development of arthropod pest and vector-borne pathogen transmission control strategies.

Crimean-Congo hemorrhagic fever (CCHF) is an emerging tick-borne zoonotic disease caused by the CCHF virus (CCHFV). In this study, an experimental approach combining RT-PCR and proteomics was used for the identification and characterization of CCHFV in 106 ticks from 7 species that were collected from small ruminants in Greece. The methodological approach included an initial screening for CCHFV by RT-PCR followed by proteomics analysis of positive and control negative tick samples. This novel approach allowed the identification of CCHFV-positive ticks and provided additional information to corroborate the RT-PCR findings using a different approach. Two ticks, Dermacentor marginatus and Haemaphysalis parva collected from a goat and a sheep, respectively were positive for CCHFV. The sequences for CCHFV RNA segments S and L were characterized by RT-PCR and proteomics analysis of tick samples, respectively. These results showed the possibility of combining analyses at the RNA and protein levels using RT-PCR and proteomics for the characterization of CCHFV in ticks. The results supported that the CCHFV identified in ticks are genetic variants of the AP92 strain. Although the AP92-like strains probably do not represent a high risk of CCHF to the population, the circulation of genetically diverse CCHFV strains could potentially result in the appearance of novel viral genotypes with increased pathogenicity and fitness.