Biology subjects

Zintl, A.

Publications and source records attributed to Zintl, A..

4 recordsLinked to original sources

bioRxiv2025

Molecular characterisation of common Culicoides Biting Midges (Diptera: Ceratopogonidae) in Ireland

BackgroundBiting midges in the genus Culicoides (Diptera: Ceratopogonidae) act as vectors for several arboviruses, including Bluetongue virus (BTV) and Schmallenberg virus (SBV), which affect livestock health and productivity. In Ireland, limited genetic data are available regarding the diversity of Culicoides species. This study represents the first attempt to characterise Culicoides in this region using molecular techniques. MethodsAdult Culicoides samples were captured using Onderstepoort Veterinary Institute (OVI) traps across six locations in Ireland. Subsequent molecular analyses involved polymerase chain reaction (PCR) and sequencing of the cytochrome oxidase subunit 1 (CO1) and the internal transcriber spacer (ITS) barcoding regions to obtain species identities. Additionally, using both markers, we inferred the population genetic structure and potential colonisation pathways of Culicoides obsoletus sensu stricto (s. str.), the major vector species in Ireland. ResultsDNA barcoding facilitated identification of 177 specimens. Eight common Culicoides species were identified through DNA barcoding of CO1 and ITS gene regions. The presence of putative vectors of Bluetongue virus (BTV) and Schmallenberg virus (SBV) were also confirmed, including species in the subgenus Avaritia (C. obsoletus s. str., C. scoticus, C. chiopterus, and C. dewulfi) and subgenus Culicoides s. str. (C. pulicaris and C. punctatus). Phylogenetic analysis confirmed the relationship between these vector species and facilitated the placement of Culicoides sp. which could not be identified to species level through DNA barcoding. Haplotype network analysis of C. obsoletus showed that some haplotypes of these species are shared between Continental Europe, the UK, and Ireland, suggesting a possible incursion pathway for this vector. ConclusionDNA barcoding employing a combination of two barcodes, CO1 and ITS, proved effective in identifying Culicoides, especially species within the obsoletus complex, which are difficult to morphologically distinguish. Our findings also suggest that investigation of the population genetic structure of Culicoides spp. could be used to model the potential introduction routes of midge-borne pathogens into the country.

molecular biology↗

bioRxiv2024

Fallow deer approaching humans are also more likely to be seropositive for Toxoplasma gondii.

Toxoplasma gondii (T. gondii) is a trophically-transmitted protozoan parasite that has been suggested to facilitate its transmission by altering intermediate hosts anti-predator behaviour, thus increasing the likelihood of completing the cycle inside its definitive host i.e. domestic and wild felines. T. gondii has been linked to reduced risk-aversion, slower reaction times, and more exploratory behaviours in intermediate hosts, including most famously weakened aversion to the scent of feline predators in mice. Studies examining this phenomenon, however, have almost exclusively been carried out in laboratory conditions with small mammals, whereas little is known about the role of T. gondii within more complex ecological contexts involving large mammals in the wild. Under such scenario, the goals of our study were three-fold. Firstly, to determine the prevalence of T. gondii infection in a population of free-living fallow deer (Dama dama) living in a park at the edge of a metropolis. Secondly, to find a link between deer seropositivity and space use in the park, namely proximity to buildings with domestic cats, where deer may have been more likely to contract the disease. Finally, to determine whether infection with T. gondii was linked to risk taking behaviour in these free ranging large mammals, namely likelihood to approach park visitors. To achieve our goals, we estimated seropositivity and combined it with spatial distribution and behavioural data of individually-recognizable deer ranging from those that avoid humans (risk-avoiders) to those who beg for food (risk-takers). We found T. gondii to be quite widespread in this population with a seropositive of 20% (24 out of 120 individuals). Contrary to our expectations, we found no correlation between T. gondii seropositivity and space use in the park, therefore not allowing us to engage with the dynamics of disease contraction. We did however find that fallow deer taking the risk of approaching humans were also more likely to be seropositive. Are risk taking individuals more likely to contract the disease? Or, alternatively, do they take more risk because they have contracted the disease? The causal mechanism behind our result has yet to be disentangled, opening new scenarios in research aimed at tackling host manipulation in this parasite. It is a fact, however, that those animals that were more likely to be in contact with the public were also those more likely to be seropositive, adding key empirical evidence to the study of zoonotic diseases. Our study is a significant contribution on the transmission and maintenance dynamics of T. gondii, offering new insights on the need to conduct longitudinal studies able to disentangle the causal mechanism and T. gondiis ability to manipulate its intermediate host.

animal behavior and cognition↗

bioRxiv2023

DNA barcoding reveals an increased diversity within the genus Culex (Diptera: Culicidae) in Ireland

Arthropod populations are changing globally due to the combined impacts of climate change, land-use transformation, globalisation and trade. Changes in arthropod populations can potentially result in the decline and extinction of some native and/or endemic species, while other species that potentially pose threats may increase. Such dynamics lead to weakened ecosystem resilience, which can facilitate the establishment and spread of species with vector capabilities, such as mosquitoes. While many of the mosquito species present in Ireland possess vector capabilities, populations have not been nationally surveyed since 1991. At that time, species identification relied on morphological examination, a method that was even then recognised as inadequate for differentiating certain species within complexes. In this study, we present the first DNA barcoding investigation of Irish mosquito populations and reveal species and hidden diversity not previously recognised in Ireland. These include two potential new species/ecotypes, Culex torrentium and Culex pipiens form pipiens, which were recorded for the first time in Ireland. We demonstrate that barcoding with Cytochrome C Oxidase Subunit 1 (COI) based primers is suitable for the majority of species-level identifications. However, additional primer sets targeting the Internal Transcribed Spacer regions 1 and 2 (ITS1 and ITS2) were necessary to differentiate species within the Culex pipiens complex. The multi-locus approach employed in this study can enhance national surveillance efforts, especially in monitoring mosquitoes that may transmit vector-borne diseases, and in recognising increased species diversity from a biodiversity perspective.

ecology↗

bioRxiv2023

Molecular Speciation of Cyathostomins From Horses In Ireland

Cyathostomins are globally important equine parasites, responsible for both chronic and acute pathogenic effects. The occurrence of mixed infections with numerous cyathostomin species hinders our understanding of parasite epidemiology, host-parasite dynamics and species pathogenicity. There have been few studies of cyathostomin species occurring in horses in Ireland, where temperate climatic conditions with year-round rainfall provide suitable conditions for infection of grazing animals with bursate nematodes. Here, we amplified and sequenced the ITS-2 region of adult worms harvested at post-mortem from 11 adult horses between August 2018 and June 2020, and recorded species prevalence and abundance of worms recovered from the caecum, right ventral colon and left dorsal colon, using both BLAST and IDTAXA for taxonomic attribution. Phylogenetic relationships and community composition were also recorded and compared with other relevant studies, including a global meta-analysis. Overall, our results agree with previous studies that there does not seem to be a major difference in cyathostomin species occurrence in equids in different geographical regions. We confirmed the results of other workers in relation to the difficulties in discriminating between Cylicostephanus calicatus and Coronocyclus coronatus on the basis of ITS-2 sequences.

molecular biology↗