Bagaza Virus in Wild Birds, Portugal, 2021.

Bagaza virus emerged in Spain in 2010 and was not reported in other countries in Europe until 2021, when the virus was detected by molecular methods in a corn bunting and several red-legged partridges in Portugal. Sequencing revealed high similarity between the 2021 strains from Portugal and the 2010 strains from Spain.

Clinical gamasoidosis and antibody response in two patients infested with Ornithonyssus bursa (Acari: Gamasida: Macronyssidae).

Blood-feeding ectoparasites constitute a growing burden for human and animal health, and animal production worldwide. In particular, mites (Acari: Gamasida) of the genera Dermanyssus (Dermanyssidae) and Ornithonyssus (Macronyssidae) infest birds and cause gamasoidosis in humans. The tropical fowl mite, Ornithonyssus bursa, is commonly found in tropical and subtropical countries but rarely reported in Europe. In this research we characterized the first two cases in Spain of clinical gamasoidosis diagnosed in patients infested with O. bursa, and investigated the IgE, IgM and IgG antibody response to mite proteins and the carbohydrate Galα1-3Galß1-(3)4GlcNAc-R (α-Gal) involved in the tick-bite associated alpha-Gal syndrome (AGS). The results suggested that O. bursa is establishing across Mediterranean countries, and may increase the risk for gamasoidosis. The immune antibody response to mite proteins was higher for IgM and similar for IgE and IgG antibodies between patients and non-allergic control individuals exposed to mite or tick bites. The anti-α-Gal antibody levels were similar between patients and controls, a result supported by the absence of this carbohydrate in mites. These results suggested that mite bites do not correlate with antibody response to acarine proteins or α-Gal, and are not associated with the AGS.

Sequencing of modern Lepus VDJ genes shows that the usage of VHn genes has been retained in both Oryctolagus and Lepus that diverged 12 million years ago.

Among mammals, the European rabbit (Oryctolagus cuniculus) has a unique mechanism of generating the primary antibody repertoire. Despite having over 200 VH genes, the VH1 gene, the most D-proximal VH gene, is used in 80-90 % of VDJ rearrangements, while the remaining 10-20 % is encoded by the VHn genes that map at least 100 Kb upstream of VH1. The maintenance of the VHn genes usage in low frequency in VDJ rearrangements has been suggested to represent a relic of an ancestral immunologic response to pathogens. To address this question, we sequenced VDJ genes for another leporid, genus Lepus, which separated from European rabbit 12 million years ago. Approximately 25 VDJ gene sequences were obtained for each one of three Lepus europaeus individuals. We found that Lepus also uses the VHn genes in 5-10 % of its VDJ rearrangements. Our results show that the VHn genes are a conserved ancestral polymorphism that has been maintained in the leporids genome and is being used for the generation of VDJ rearrangements by both modern Lepus and Oryctolagus.

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.

Characterization by Quantitative Serum Proteomics of Immune-Related Prognostic Biomarkers for COVID-19 Symptomatology.

The COVID-19 pandemic caused by SARS-CoV-2 challenges the understanding of factors affecting disease progression and severity. The identification of prognostic biomarkers and physiological processes associated with disease symptoms is relevant for the development of new diagnostic and therapeutic interventions to contribute to the control of this pandemic. To address this challenge, in this study, we used a quantitative proteomics together with multiple data analysis algorithms to characterize serum protein profiles in five cohorts from healthy to SARS-CoV-2-infected recovered (hospital discharge), nonsevere (hospitalized), and severe [at the intensive care unit (ICU)] cases with increasing systemic inflammation in comparison with healthy individuals sampled prior to the COVID-19 pandemic. The results showed significantly dysregulated proteins and associated biological processes and disorders associated to COVID-19. These results corroborated previous findings in COVID-19 studies and highlighted how the representation of dysregulated serum proteins and associated BPs increases with COVID-19 disease symptomatology from asymptomatic to severe cases. The analysis was then focused on novel disease processes and biomarkers that were correlated with disease symptomatology. To contribute to translational medicine, results corroborated the predictive value of selected immune-related biomarkers for disease recovery [Selenoprotein P (SELENOP) and Serum paraoxonase/arylesterase 1 (PON1)], severity [Carboxypeptidase B2 (CBP2)], and symptomatology [Pregnancy zone protein (PZP)] using protein-specific ELISA tests. Our results contributed to the characterization of SARS-CoV-2-host molecular interactions with potential contributions to the monitoring and control of this pandemic by using immune-related biomarkers associated with disease symptomatology.

Characterization of the bacterial microbiota in wild-caught Ixodes ventalloi.

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.

Contributions to the morphology and phylogeny of the newly discovered bat tick species, Ixodes ariadnae in comparison with I. vespertilionis and I. simplex.

BACKGROUND: Recently a new hard tick species, Ixodes ariadnae has been discovered, adding to the two known ixodid tick species (I. vespertilionis and I. simplex) of bats in Europe. FINDINGS: Scanning electron microscopic comparison of adult females of these species shows morphological differences concerning the palps, the scutum, the Haller's organ, the coxae, as well as the arrangement and fine structure of setae. Molecular analysis of 10 geographically different isolates revealed 90-95% sequence homology in the 12S and 16S rDNA genes of bat tick species. Based on 12S rDNA sequences, genotypes of I. ariadnae clustered closest to I. simplex, whereas according to their 16S rDNA gene they were closest to I. vespertilionis. The subolesin gene of I. ariadnae had only 91% sequence homology with that of I. ricinus, and is the longest known among hard tick species. CONCLUSIONS: The present study illustrates the morphology and clarifies the phylogenetic relationships of the three known bat tick species that occur in Europe. According to its subolesin gene I. ariadnae may have a long evolutionary history.

Proteomics approach to the study of cattle tick adaptation to white tailed deer.

Cattle ticks, Rhipicephalus (Boophilus) microplus, are a serious threat to animal health and production. Some ticks feed on a single host species while others such as R. microplus infest multiple hosts. White tailed deer (WTD) play a role in the maintenance and expansion of cattle tick populations. However, cattle ticks fed on WTD show lower weight and reproductive performance when compared to ticks fed on cattle, suggesting the existence of host factors that affect tick feeding and reproduction. To elucidate these factors, a proteomics approach was used to characterize tick and host proteins in R. microplus ticks fed on cattle and WTD. The results showed that R. microplus ticks fed on cattle have overrepresented tick proteins involved in blood digestion and reproduction when compared to ticks fed on WTD, while host proteins were differentially represented in ticks fed on cattle or WTD. Although a direct connection cannot be made between differentially represented tick and host proteins, these results suggested that differentially represented host proteins together with other host factors could be associated with higher R. microplus tick feeding and reproduction observed in ticks fed on cattle.

Non-pet dogs as sentinels and potential synanthropic reservoirs of tick-borne and zoonotic bacteria.

Blood samples were collected from 100 shepherd dogs, 12 hunting dogs and 14 stray dogs (apparently healthy) in southern Hungary to screen for the presence of emerging tick-borne pathogens. Based on real-time PCR results, 14 dogs (11%) had single or dual haemoplasma infection, and a same number of samples were positive for Anaplasma phagocytophilum. In one sample Coxiella burnetii was molecularly identified, and 20.3% of dogs seroconverted to the Q fever agent. Rickettsaemia (sensu stricto) was also detected in one animal. This is the first molecular evidence of autochthonous infection of dogs with the above pathogens in Hungary. The relatively high prevalence of haemoplasma and anaplasma infection among non-pet dogs is suggestive of a prolonged carrier status and bacteraemia of these animals rendering them epidemiologically significant as potential reservoirs and sentinels for tick-borne infections.

Lesser protein degradation machinery correlates with higher BM86 tick vaccine efficacy in Rhipicephalus annulatus when compared to Rhipicephalus microplus.

Infestations with cattle ticks, Rhipicephalus (Boophilus) microplus and Rhipicephalus annulatus, economically impact cattle production in tropical and subtropical regions of the world. Vaccines containing the recombinant R. microplus BM86 gut antigen were developed and commercialized to induce an immunological protection in cattle against tick infestations. These vaccines demonstrated that tick control by vaccination is cost-effective, reduces environmental contamination and prevents the selection of drug resistant ticks that result from repeated acaricide applications. The protection elicited by BM86-containing vaccines against tick infestations is mediated by a collaborative action between the complement system and IgG antibodies. The efficacy of the vaccination with BM86 and other tick antigens is always higher for R. annulatus than against R. microplus, suggesting that tick genetic and/or physiological factors may affect tick vaccine efficacy. These factors may be related to BM86 protein levels or tick physiological processes such as feeding and protein degradation that could result in more efficient antibody-antigen interactions and vaccine efficacy. To test this hypothesis, we compared the proteome in R. annulatus and R. microplus female ticks after feeding on BM86-vaccinated and control cattle. The results showed that cattle proteins were under represented in R. annulatus when compared to R. microplus, suggesting that R. annulatus ticks ingested less blood, a difference that increased when feeding on vaccinated cattle, probably reflecting the effect of antibody-BM86 interactions on this process. The results also showed that tick protein degradation machinery was under represented in R. annulatus when compared to R. microplus. BM86 mRNA and protein levels were similar in both tick species, suggesting that lesser protease activity in R. annulatus results in more efficient antibody-antigen interactions and higher vaccine efficacy. These results have important implications for tick vaccine research, indicating that not only genetic differences, but also physiological factors may influence tick vaccine efficacy.

Molecular identification of tick-borne pathogens in Nigerian ticks.

A molecular epidemiology investigation was undertaken in two Nigerian states (Plateau and Nassarawa) to determine the prevalence of pathogens of veterinary and public health importance associated with ticks collected from cattle and dogs using PCR, cloning and sequencing or reverse line blot techniques. A total of 218 tick samples, Amblyomma variegatum (N=153), Rhipicephalus (Boophilus) decoloratus (N=45), and Rhipicephalus sanguineus (N=20) were sampled. Pathogens identified in ticks included piroplasmids (Babesia spp., Babesia bigemina and Babesia divergens), Anaplasma marginale and Rickettsia africae. Piroplasmids were identified in A. variegatum, A. marginale was found in R. decoloratus, while R. africae was detected in all tick species examined. Ehrlichia spp. and Theileria spp. were not identified in any of the ticks examined. Of the 218 ticks examined, 33 (15.1%) contained pathogen DNA, with the presence of B. divergens and R. africae that are zoonotic pathogens of public health and veterinary importance. The variety of tick-borne pathogens identified in this study suggests a risk for the emergence of tick-borne diseases in domestic animals and humans, especially amongst the Fulani pastoralists in Plateau and Nassarawa states of Nigeria.