Ixodes Uriae Research Articles

New tick records with notes on rickettsial infection from the wildlife of the state of Espírito Santo, southeastern Brazil

This work aimed to report ticks infesting the wildlife among 15 municipalities of the state of Espírito Santo between 2016 and 2021, within the Atlantic Forest biome of southeastern Brazil. A total of 576 tick specimens (187 males, 56 females, 149 nymphs, and 184 larvae) was collected from 41 species of wild vertebrates (two reptiles, nine mammals, and 30 birds). Ticks were identified by morphological or molecular methods into 18 species, being 12, four, one and one of the genera Amblyomma, Ixodes, Rhipicephalus and Ornithodoros, respectively. Amblyomma rotundatum was the only species collected from reptiles. Ticks collected from mammals were identified as Amblyomma brasiliense, Amblyomma calcaratum, Amblyomma dubitatum, Amblyomma longirostre, Amblyomma nodosum, Amblyomma pacae, Amblyomma sculptum, Amblyomma varium and Rhipicephalus microplus. Amblyomma sculptum was the species found on the widest variety of hosts, collected from four mammal orders and five bird orders. Passeriformes birds were infested by Amblyomma fuscum, A. longirostre (also found on non- passerine birds), A. nodosum, Amblyomma parkeri, Amblyomma romarioi, A. varium and Ixodes loricatus. An adult female of Ixodes rio was collected from a Piciformes bird. Seabirds of the order Procellariiformes were infested by Ixodes percavatus sensu lato and Ixodes uriae. The argasid Ornithodoros capensis was collected from an offshore metallic platform that was used by Suliformes seabirds. Rickettsial agents of the spotted fever group, Rickettsia amblyommatis and Rickettsia sp. strain Pampulha, were detected in the ticks A. longirostre [from the Paraguayan hairy dwarf porcupine (Coendou spinosus)] and A. dubitatum [from the capybara (Hydrochoerus hydrochaeris)], respectively. The following nine tick species are reported for the first time in Espírito Santo state: A. calcaratum, A. fuscum, A. pacae, A. parkeri, A. romarioi, I. loricatus, I. rio, I. uriae, and O. capensis. Although it is also the first report of I. uriae in Brazil, we do not consider it established in the country. Multiple new tick-host associations are reported in the present study.

Molecular-phylogenetic analyses of Ixodes species from South Africa suggest an African origin of bird-associated exophilic ticks (subgenus Trichotoixodes)

BackgroundAmong hard ticks (Acari: Ixodidae), the genus Ixodes comprises the highest number of species, which in turn are most numerous in the Afrotropical zoogeographic region. In South Africa extensive morphological studies have been performed on Ixodes species but only few reports included molecular analyses.MethodsIn this study, 58 Ixodes spp. ticks, collected from ten mammalian and eight avian host species in South Africa, were molecularly and phylogenetically analyzed. In addition, a newly collected sample of the Palearctic Ixodes trianguliceps was included in the analyses.ResultsAmong the ticks from South Africa, 11 species were identified morphologically. The majority of ticks from mammals represented the Ixodes pilosus group with two species (n = 20), followed by ticks resembling Ixodes rubicundus (n = 18) and Ixodes alluaudi (n = 3). In addition, single specimens of Ixodes rhabdomysae, Ixodes ugandanus, Ixodes nairobiensis and Ixodes simplex were also found. Considering bird-infesting ticks, Ixodes theilerae (n = 7), Ixodes uriae (n = 4) and ticks most similar to Ixodes daveyi (provisionally named I. cf. daveyi, n = 2) were identified. Molecular analyses confirmed two species in the I. pilosus group and a new species (I. cf. rubicundus) closely related to I. rubicundus sensu stricto. Phylogenetic trees based on concatenated mitochondrial or mitochondrial and nuclear gene sequences indicated that the subgenus Afrixodes forms a monophyletic clade with bird-associated exophilic ticks (subgenus Trichotoixodes). Ixodes trianguliceps clustered separately whereas I. alluaudi with their morphologically assigned subgenus, Exopalpiger.ConclusionsPhylogenetic analyses shed new lights on the relationships of Ixodes subgenera when including multiple sequences from subgenus Afrixodes and African as well as Palearctic species of subgenera Trichotoixodes and Exopalpiger. Subgenera Afrixodes and bird-associated Trichotoixodes share common ancestry, suggesting that the latter might have also originated in Africa. Regarding the subgenus Exopalpiger, I. alluaudi is properly assigned as it clusters among different Australian Ixodes, whereas I. trianguliceps should be excluded.Graphical

Genome diversity of Borrelia garinii in marine transmission cycles does not match host associations but reflects the strains evolutionary history

Borrelia burgdorferi sensu lato is a species complex of spirochetal bacteria that occupy different ecological niches which is reflected in their reservoir host- and vector-associations. Borrelia genomes possess numerous linear and circular plasmids. Proteins encoded by plasmid genes play a major role in host- and vector-interaction and are important for Borrelia niche adaptation. However, the plasmid composition and therewith the gene repertoire may vary even in strains of a single species.Borrelia garinii, one of the six human pathogenic species, is common in Europe (vector Ixodes ricinus), Asia (vector Ixodes persulcatus) and in marine birds (vector Ixodes uriae). For the latter, only a single culture isolate (Far04) and its genome were previously available. The genome was rather small containing only one circular and six linear plasmids with a notable absence of cp32 plasmids. To further investigate B. garinii from marine transmission cycles and to explore i) whether the small number of plasmids found in isolate Far04 is a common feature in B. garinii from marine birds and presents an adaptation to this particular niche and ii) whether there may be a correlation between genome type and host species, we initiated in vitro cultures from live I. uriae collected in 2017 and 2018 from marine avian hosts and their nests. Hosts included common guillemots, Atlantic Puffin, razorbill, and kittiwake.We obtained 17 novel isolates of which 10 were sequenced using Illumina technology, one also with Pacific Bioscience technology. The 10 genomes segregated into five different genome types defined by plasmid types (based on PFam32 loci). We show that the genomes of seabird associated B. garinii contain fewer plasmids (6–9) than B. garinii from terrestrial avian species (generally ≥10), potentially suggesting niche adaptation. However, genome type did not match an association with the diverse avian seabird hosts investigated but matched the clonal complex they originated from, perhaps reflecting the isolates evolutionary history.Questions that should be addressed in future studies are (i) how is plasmid diversity related to host- and/or vector adaptation; (ii) do the different seabird species differ in reservoir host competence, and (iii) can the genome types found in seabirds use terrestrial birds as reservoir hosts.

Ticks and tick-borne microbes identified through passive and active surveillance in Alaska.

Rapid environmental change in Alaska and other regions of the Arctic and sub-Arctic has raised concerns about increasing human exposure to ticks and the pathogens they carry. We tested a sample of ticks collected through a combination of passive and active surveillance from humans, domestic animals, and wildlife hosts in Alaska for a panel of the most common tick-borne pathogens in the contiguous United States to characterize the diversity of microbes present in this region. We tested 189 pooled tick samples collected in 2019-2020 for Borrelia spp., Anaplasma spp., Ehrlichia spp., and Babesia spp. using a multiplex PCR amplicon sequencing assay. We found established populations of Ixodes angustus Neumann (Acari: Ixodidae), Ixodes uriae White (Acari: Ixodidae), and Haemaphysalis leporispalustris Packard (Acari: Ixodidae) in Alaska, with I. angustus found on a variety of hosts including domestic companion animals (dogs and cats), small wild mammals, and humans. Ixodes angustus were active from April through October with peaks in adult and nymphal activity observed in summer months (mainly July). Although no known human pathogens were detected, Babesia microti-like parasites and candidatus Ehrlichia khabarensis were identified in ticks and small mammals. The only human pathogen detected (B. burgdorferi s.s.) was found in a tick associated with a dog that had recently traveled to New York, where Lyme disease is endemic. This study highlights the value of a combined passive and active tick surveillance system to detect introduced tick species and pathogens and to assess which tick species and microbes are locally established.

Worldwide host associations of the tick genus Ixodes suggest relationships based on environmental sharing rather than on co-phylogenetic events

BackgroundThis study aims to capture how ticks of the genus Ixodes gained their hosts using network constructs. We propose two alternative hypotheses, namely, an ecological background (ticks and hosts sharing environmentally available conditions) and a phylogenetic one, in which both partners co-evolved, adapting to existing environmental conditions after the association took place.MethodsWe used network constructs linking all the known pairs of associations between each species and stage of ticks with families and orders of hosts. Faith’s phylogenetic diversity was used to evaluate the phylogenetic distance of the hosts of each species and changes occurring in the ontogenetic switch between consecutive stages of each species (or the extent of the changes in phylogenetic diversity of hosts for consecutive stages of the same species).ResultsWe report highly clustered associations among Ixodes ticks and hosts, supporting the influence of the ecological adaptation and coexistence, demonstrating a lack of strict tick-host coevolution in most cases, except for a few species. Keystone hosts do not exist in the relationships between Ixodes and vertebrates because of the high redundancy of the networks, further supporting an ecological relationship between both types of partners. The ontogenetic switch of hosts is high for species with enough data, which is another potential clue supporting the ecological hypothesis. Other results suggest that the networks displaying tick-host associations are different according to the biogeographical realms. Data for the Afrotropical region reveal a lack of extensive surveys, while results for the Australasian region are suggestive of a mass extinction of vertebrates. The Palearctic network is well developed, with many links demonstrating a highly modular set of relationships.ConclusionsWith the obvious exceptions of Ixodes species restricted to one or a few hosts, the results point to an ecological adaptation. Even results on species linked to groups of ticks (such as Ixodes uriae and the pelagic birds or the bat-tick species) are suggestive of a previous action of environmental forces.Graphical

Climate change in the Arctic: Testing the poleward expansion of ticks and tick-borne diseases.

Climate change is most strongly felt in the polar regions of the world, with significant impacts on the species that live there. The arrival of parasites and pathogens from more temperate areas may become a significant problem for these populations, but current observations of parasite presence often lack a historical reference of prior absence. Observations in the high Arctic of the seabird tick Ixodes uriae suggested that this species expanded poleward in the last two decades in relation to climate change. As this tick can have a direct impact on the breeding success of its seabird hosts and vectors several pathogens, including Lyme disease spirochaetes, understanding its invasion dynamics is essential for predicting its impact on polar seabird populations. Here, we use population genetic data and host serology to test the hypothesis that I. uriae recently expanded into Svalbard. Both black-legged kittiwakes (Rissa tridactyla) and thick-billed murres (Uria lomvia) were sampled for ticks and blood in Kongsfjorden, Spitsbergen. Ticks were genotyped using microsatellite markers and population genetic analyses were performed using data from 14 reference populations from across the tick's northern distribution. In contrast to predictions, the Spitsbergen population showed high genetic diversity and significant differentiation from reference populations, suggesting long-term isolation. Host serology also demonstrated a high exposure rate to Lyme disease spirochaetes (Bbsl). Targeted PCR and sequencing confirmed the presence of Borrelia garinii in a Spitsbergen tick, demonstrating the presence of Lyme disease bacteria in the high Arctic for the first time. Taken together, results contradict the notion that I. uriae has recently expanded into the high Arctic. Rather, this tick has likely been present for some time, maintaining relatively high population sizes and an endemic transmission cycle of Bbsl. Close future observations of population infestation/infection rates will now be necessary to relate epidemiological changes to ongoing climate modifications.

Within and among population differences in cuticular hydrocarbons in the seabird tick Ixodes uriae

The hydrophobic layer of the arthropod cuticle acts to maintain water balance, but can also serve to transmit chemical signals via cuticular hydrocarbons (CHC), essential mediators of arthropod behavior. CHC signatures typically vary qualitatively among species, but also quantitatively among populations within a species, and have been used as taxonomic tools to differentiate species or populations in a variety of taxa. Most work in this area to date has focused on insects, with little known for other arthropod groups such as ticks. The worldwide distribution and extensive host-range of the seabird tick Ixodes uriae make it a good model to study the factors influencing CHC composition. Genetically differentiated host-races of I. uriae have evolved across the distribution of this species but the factors promoting sympatric population divergence are still unknown. To test for a potential role of host-associated CHC in population isolation, we collected I. uriae specimens from two of its seabird hosts, the Atlantic puffin (Fratercula arctica) and the common guillemot (Uria aalge) in different colonies in Iceland. Using gas-chromatography and mass-spectrometry, we detected a complex cuticular mixture of 22 hydrocarbons, including n-alkanes, methyl-alkanes and alkenes ranging from 17 to 33 carbons in length. We found that each population had a distinct CHC profile. The host group explained the greatest amount of population divergence, with long-chain hydrocarbons being more abundant in puffin tick populations compared to guillemot tick populations. Future work will now be required to test whether the different CHC signals reinforce assortative mating, thereby playing a role in generating I. uriae population divergence patterns, and to evaluate diverse hypotheses on the origin of distinct population signatures.

Ticks (Acari: Ixodidae) parasitizing migrating and local breeding birds in Finland

Ticks are globally renowned vectors for numerous zoonoses, and birds have been identified as important hosts for several species of hard ticks (Acari: Ixodidae) and tick-borne pathogens. Many European bird species overwinter in Africa and Western Asia, consequently migrating back to breeding grounds in Europe in the spring. During these spring migrations, birds may transport exotic tick species (and associated pathogens) to areas outside their typical distribution ranges. In Finland, very few studies have been conducted regarding ticks parasitizing migrating or local birds, and existing data are outdated, likely not reflecting the current situation. Consequently, in 2018, we asked volunteer bird ringers to collect ticks from migrating and local birds, to update current knowledge on ticks found parasitizing birds in Finland. In total 430 ticks were collected from 193 birds belonging to 32 species, caught for ringing between 2018 and 2020. Furthermore, four Ixodes uriae were collected from two roosting islets of sea birds in 2016 and 2020. Ticks collected on birds consisted of: Ixodes ricinus (n = 421), Ixodes arboricola (4), Ixodes lividus (2) and Hyalomma marginatum (3). Ixodes ricinus loads (nymphs and larvae) were highest on thrushes (Passeriformes: Turdidae) and European robins (Erithacus rubecula). The only clearly imported exotic tick species was H. marginatum. This study forms the second report of both I. uriae and I. arboricola from Finland, and possibly the northernmost observation of I. arboricola from Europe. The importation of exotic tick species by migrating birds seems a rare occurrence, as over 97% of all ticks collected from birds arriving in Finland during their spring migrations were I. ricinus, a species native to and abundant in Finland.

Cross-tolerance and transcriptional shifts underlying abiotic stress in the seabird tick, Ixodes uriae

Cross-tolerance and transcriptional shifts underlying abiotic stress in the seabird tick, Ixodes uriae

Cold hardening improves larval tick questing under low temperatures at the expense of longevity

Questing in ticks is essential for locating a host, and this behavioral response can occur at regionally specific low temperatures for most tick species. Little is known about the dynamics between tick questing behavior and temperature in ticks, specifically how this may impact other aspects of tick biology. Here, we examine whether cold hardening increases questing in three larval tick species (Ixodes uriae, Dermacentor variabilis, and Amblyomma americanum) at low temperatures and whether cold hardening impacts longevity. Rapid cold hardening and prolonged cold acclimation benefitted ticks by decreasing the temperature of chill coma onset, and increased survival, activity, and questing in ticks at low temperatures. Oxygen consumption increased at low temperatures following acclimation in larvae, suggesting this process has a distinct metabolic expense. This increased metabolism associated with hardening led to a substantial reduction in larval longevity as nutrient reserves are limited and cannot be replenished until a host is located. These studies suggest that tick larvae, and likely other developmental stages, require a delicate balance between the need for questing at low temperatures and survival until the first blood meal.

Changes in Bacterial Diversity, Composition and Interactions During the Development of the Seabird Tick Ornithodoros maritimus (Argasidae).

Characterising within-host microbial interactions is essential to understand the drivers that shape these interactions and their consequences for host ecology and evolution. Here, we examined the bacterial microbiota hosted by the seabird soft tick Ornithodoros maritimus (Argasidae) in order to uncover bacterial interactions within ticks and how these interactions change over tick development. Bacterial communities were characterised through next-generation sequencing of the V3-V4 hypervariable region of the bacterial 16S ribosomal RNA gene. Bacterial co-occurrence and co-exclusion were determined by analysing networks generated from the metagenomic data obtained at each life stage. Overall, the microbiota of O. maritimus was dominated by four bacterial genera, namely Coxiella, Rickettsia, Brevibacterium and Arsenophonus, representing almost 60% of the reads. Bacterial diversity increased over tick development, and adult male ticks showed higher diversity than did adult female ticks. Bacterial networks showed that co-occurrence was more frequent than co-exclusion and highlighted substantial shifts across tick life stages; interaction networks changed from one stage to the next with a steady increase in the number of interactions through development. Although many bacterial interactions appeared unstable across life stages, some were maintained throughout development and were found in both sexes, such as Coxiella and Arsenophonus. Our data support the existence of a few stable interactions in O. maritimus ticks, on top of which bacterial taxa accumulate from hosts and/or the environment during development. We propose that stable associations delineate core microbial interactions, which are likely to be responsible for key biological functions.

Local, but not long-distance dispersal of penguin ticks between two sub-Antarctic islands

Advances in high throughput genomic approaches are enabling the accurate appraisal of movements of diverse species, previously considered intractable. The impact of long-distance dispersal and distribution changes on species interactions (such as host-parasite interactions) is of particular importance as attempts are made to project how ecosystems will shift under environmental change. The sub-Antarctic region, comprising isolated islands separated by hundreds to thousands of kilometres of open ocean, presents an ideal model system for studying long-distance dispersal, distribution, and ecosystem change. Here we used genomic methods to determine the extent of movement of penguin ticks (Ixodes uriae) among different host species, and among penguin colonies at small (within an island) and large (among islands separated by >6000 km) scales, in the sub-Antarctic region. Our results suggest that I. uriae ticks may be readily shared between distantly related penguin species with similar phenology, but indicate that – as inferred by previous research – ticks are less likely to be shared between flighted and non-flighted sea- birds. We also find evidence for small-scale movements of penguin ticks with their hosts, but no evidence for movements between islands separated by thousands of kilometers of open ocean. These inferred limitations to penguin tick movement could be the result of restricted host movements or the inability of penguin ticks to survive extended trips at sea. Our findings help elucidate parasite-host dynamics, with implications for host health and persistence in a region experiencing rapid environmental change.

Circumpolar diversification of the Ixodes uriae tick virome.

Ticks (order: Ixodida) are a highly diverse and ecologically important group of ectoparasitic blood-feeding organisms. One such species, the seabird tick (Ixodes uriae), is widely distributed around the circumpolar regions of the northern and southern hemispheres. It has been suggested that Ix. uriae spread from the southern to the northern circumpolar region millions of years ago and has remained isolated in these regions ever since. Such a profound biographic subdivision provides a unique opportunity to determine whether viruses associated with ticks exhibit the same evolutionary patterns as their hosts. To test this, we collected Ix. uriae specimens near a Gentoo penguin (Pygoscelis papua) colony at Neko harbour, Antarctica, and from migratory birds—the Razorbill (Alca torda) and the Common murre (Uria aalge)—on Bonden island, northern Sweden. Through meta-transcriptomic next-generation sequencing we identified 16 RNA viruses, seven of which were novel. Notably, we detected the same species, Ronne virus, and two closely related species, Bonden virus and Piguzov virus, in both hemispheres indicating that there have been at least two cross-circumpolar dispersal events. Similarly, we identified viruses discovered previously in other locations several decades ago, including Gadgets Gully virus, Taggert virus and Okhotskiy virus. By identifying the same or closely related viruses in geographically disjunct sampling locations we provide evidence for virus dispersal within and between the circumpolar regions. In marked contrast, our phylogenetic analysis revealed no movement of the Ix. uriae tick hosts between the same locations. Combined, these data suggest that migratory birds are responsible for the movement of viruses at both local and global scales.

Establishing a baseline for tick surveillance in Alaska: Tick collection records from 1909-2019

The expanding geographic ranges of tick species that are known pathogen vectors can have implications for human, domestic animal, and wildlife health. Although Alaska is home to several hard tick species, it has historically been outside of the range of the most common medically important ticks in the contiguous United States and western Canada. To assess the status of tick species establishment in the state and to provide a baseline for tracking future change in the distribution of ticks, we reviewed and compiled historical tick records and summarized recent tick occurrence records collected through the development of the Alaska Submit-A-Tick Program and through tick drag sampling at sentinel sites in southcentral Alaska. Between 1909–2019, there were 1190 tick records representing 4588 individual ticks across 15 species in Alaska. The majority of ticks were species historically found in Alaska: Haemaphysalis leporispalustris, Ixodes angustus, Ixodes auritulus, Ixodes howelli, Ixodes signatus, and Ixodes uriae. Over half of all tick records in the state were collected in the last 10 yr. During this time, the number of tick records and the number of tick species recorded in Alaska each year has increased substantially. Between 2010–2019, there were 611 tick records representing 1921 individual ticks. The most common hosts for reported ticks were domestic animals (n = 343, 56 %) followed by small wild mammals (n = 147, 24 %), humans (n = 49, 8%), and wild birds (n = 31, 5%). Less than 5% of records (n = 25) were of unattached ticks found in the environment. Since 2007, non-native tick species have been documented in the state every year, including Amblyomma americanum, Dermacentor andersoni, Dermacentor occidentalis, Dermacentor variabilis, Ixodes pacificus, Ixodes ricinus, Ixodes scapularis, Ixodes texanus, and Rhipicephalus sanguineus sensu lato (s.l.). Almost half of the records (n = 68, 48 %) of non-native tick species from 2010 to 2019 represented ticks found on a host (usually a dog or a human) that had traveled outside of Alaska in the two weeks prior to collection. However, A. americanum, D. variabilis, I. pacificus, I. texanus, and R. sanguineus s.l. have been found on humans and domestic animals in Alaska without reported recent travel. In particular, there is evidence to suggest that there is local establishment of R. sanguineus s.l. in Alaska. A tick species historically found in the state, I. angustus was frequently found on human and dogs, suggesting a potential role as a bridge vector of pathogens. Given the inconsistency of tick monitoring in Alaska over the past century, it is difficult to draw many conclusions from temporal trends in the data. Continued monitoring through the Alaska Submit-A-Tick Program will allow a more accurate assessment of the changing risk of ticks and tick-borne diseases in the state and provide information for setting clinical and public health guidelines for tick-borne disease prevention.

Infestation of small seabirds by Ornithodoros maritimus ticks: Effects on chick body condition, reproduction and associated infectious agents

Ticks can negatively affect their host by direct effects as blood feeding causing anaemia or discomfort, or by pathogen transmission. Consequently, ticks can have an important role in the population dynamics of their hosts. However, specific studies on the demographic effects of tick infestation on seabirds are still scarce. Seabird ticks have also the potential to be responsible for the circulation of little known tick-borne agents, which could have implications for non-seabird species. Here, we report the results of investigations on potential associations between soft tick Ornithodoros maritimus load and reproductive parameters of storm petrels Hydrobates pelagicus breeding in a large colony in a cave of Espartar Island, in the Balearic archipelago. We also investigated by molecular analyses the potential viral and bacterial pathogens associated with O. maritimus ticks present at the colony. Lower nestling survival was recorded in the most infested area, deep in the cave, compared to the area near the entrance. The parasite load was negatively associated with the body condition of the nestlings. One pool of ticks tested positive for West Nile virus and 4 pools tested positive for a Borrelia species which was determined by targeted nested PCR to have a 99% sequence identity with B. turicatae, a relapsing fever Borrelia. Overall, these results show that further investigations are needed to better understand the ecology and epidemiology of the interactions between ticks, pathogens and Procellariiform species.

Genetic diversity of Borrelia garinii from Ixodes uriae collected in seabird colonies of the northwestern Atlantic Ocean

The occurrence of Borrelia garinii in seabird ticks, Ixodes uriae, associated with different species of colonial seabirds has been studied since the early 1990s. Research on the population structure of this bacterium in ticks from seabird colonies in the northeastern Atlantic Ocean has revealed admixture between marine and terrestrial tick populations. We studied B. garinii genetic diversity and population structure in I. uriae collected from seabird colonies in the northwestern Atlantic Ocean, in Newfoundland and Labrador, Canada. We applied a multi-locus sequence typing (MLST) scheme to B. garinii found in ticks from four species of seabirds. The B. garinii strains found in this seabird colony ecosystem were diverse. Some were very similar to strains from Asia and Europe, including some obtained from human clinical samples, while others formed a divergent group specific to this region of the Atlantic Ocean. Our findings highlight the genetic complexity of B. garinii circulating in seabird ticks and their avian hosts but also demonstrate surprisingly close connections between B. garinii in this ecosystem and terrestrial sources in Eurasia. Genetic similarities among B. garinii from seabird ticks and humans indicate the possibility that B. garinii circulating within seabird tick-avian host transmission cycles could directly, or indirectly via connectivity with terrestrial transmission cycles, have consequences for human health.

Novel Ehrlichia sp. detected in Magellanic penguins (Sphenicus magellanicus) and in the seabird tick Ixodes uriae from Magdalena Island, southern Chile

Ehrlichia spp. are obligatory intracellular microorganisms that infect hematopoietic, endothelial or blood cells of mammals. Ticks are the only vectors of these agents in nature. To date, the role of birds and their associated ticks as reservoirs of ehrlichiae remains almost unexplored. In this study, we performed a molecular screening for bacteria of Anaplasmataceae family in samples of spleen (n = 72) and lung (n = 17), recovered from 72 carcasses of Magellanic penguins (Spheniscus magellanicus) in Brazil and Chile. One apparently unengorged tick (Ixodes uriae) was also collected while wandering upon one of the carcasses and submitted to molecular analyses as well. Through conventional and nested PCR protocols three genes (16S rRNA, dsb and groEL) of a new Ehrlichia sp. were partially characterized upon organs of three penguins and in the tick coming from Magdalena Island (Chile). First matches after BLASTn comparisons showed that our sequences share 99.4% (16S rRNA), 94.6% (groEL) and 79.3% (dsb) of identity with “Candidatus Ehrlichia ornithorhynchi”, Ehrlichia sp. NS101 and Ehrlichia canis CCZ, respectively. Matrixes of genetic distance including other representatives of the Ehrlichia genus point a 99.4%, 94.0%, and 80.0% of identity with 16S rRNA, groEL and dsb genes from Ehrlichia sp. It25, Ehrlichia sp. NS101, and Ehrlichia chaffeensis San Louis, respectively. A Bayesian phylogenetic analysis of Anaplasmataceae 16S rRNA gene places the detected Ehrlichia sp. into a group with Ehrlichia sp. BAT and Ehrlichia sp. Natal. Although depicting different topologies, Bayesian unrooted phylogenetic trees constructed for groEL and dsb genes position this Ehrlichia sp. into well-supported branches, which reinforces the finding of a new taxon. For the moment, any pathogenic effect of this new Ehrlichia sp. on penguins is still unknown. However, this fact becomes important to assess from a conservation point of view since populations of Magellanic penguins are currently threatened and in an ongoing decrease.

St. Abb’s Head phlebovirus – a separate virus species or a strain of Uukuniemi phlebovirus?

St. Abb’s Head virus (SAHV), a member of the genus Phlebovirus (family Phenuiviridae, order Bunyavirales), belongs to the largest group of negative strand RNA viruses. All phleboviruses share a genome structure that comprises three segments of negative-sense or ambi-sense RNA. The viral genome is composed of the small (S), medium (M) and large (L) RNA segments. The S segment encodes the nucleocapsid (N) protein, the M segment encodes the precursor for the viral glycoproteins (Gn and Gc) and the L segment encodes the viral RNA-dependent RNA polymerase (RdRp). Some viruses within the genus also encode non-structural proteins within their S or M segments. SAHV was isolated from a pool of seabird ticks (Ixodes uriae) collected at a seabird colony in St. Abb’s Head National Nature Reserve, Berwickshire, Scotland in 1979. Antigenically, SAHV appeared to be related to the Uukuniemi serogroup of phleboviruses. Similarly, the proteins of SAHV shared similar biochemical properties to Uukuniemi phlebovirus. Here, we describe an in depth molecular characterisation of SAHV. Using next generation sequencing technology, we demonstrate that SAHV is very closely related to the Uukuniemi phlebovirus (UUKV). We examine the growth of SAHV in mammalian, avian and tick celllines and define its target cell tropism.

Tick infestations correlates at a Falkland Islands Black-browed Albatross colony

The tick Ixodes uriae is an ectoparasite widely distributed among seabirds throughout circumpolar regions, usually associated with seabird colonies. Nevertheless, potential effects of infestations, especially in chicks, are not well documented. In this article, we studied factors associated with probability and intensity of infestations in Black-browed Albatross Thalassarche melanophrys nestlings in a colony at the Falklands Islands. We compared the body measurements, physiological parameters, distance to other nests and position inside the colony between infested and non-infested 40 Black-browed Albatross nestlings. Ticks were present in 60% of the nestlings with a mean number per nestlings of 1.47. None of the 12 analysed blood parameters but LDH (Lactate dehydrogenase) showed significant differences between infested and not infested nestlings. Nestlings infected showed significant higher level of LDH than those without ticks. The number of ticks found on each nestling was positively and significantly correlated with their LDH blood levels. Tarsus length (as a proxy of age) and distance to the nearest nest showed a significant effect, with younger nestlings with closer nests showing higher probability to be infected. These variables also affect intensity of infestation. No effects of nutritional condition (butyrate or urea levels) or body condition (residuals of cubic root of mass/tarsus length regression) on probability or intensity of infestation were found. Both small anaemias and tick scars would explain the different values of LDH between infected/non-infected chicks. The low level of infestation found in our colony could be the cause of a non-detectable effect of the presence of ticks on nestling body condition and other blood parameters related to metabolism of fat or protein.

Limited consequences of infestation with a blood‐feeding ectoparasite for the nestlings of two North Pacific seabirds

The seabird tick Ixodes uriae parasitizes over 60 host species in the circumpolar regions of both hemispheres. To assess the impacts of these ticks on the growth and development of nestling seabirds, we used a logistic growth model to interpolate between successive measures of mass (g) and wing chord (mm) for 558 Cassin's auklet Ptychoramphus aleuticus and 344 rhinoceros auklet Cerorhinca monocerata chicks over 11 years (1997–2008, less 2003) on Triangle Island, British Columbia, Canada. From the model, we estimated the asymptotic measure and the age at inflection point for each chick's growth trajectory, and assessed their relationships with tick load relative to other sources of annual and seasonal variation in growth. Most chicks (72.4% of Cassin's auklets, 62.2% of rhinoceros auklets) hosted ≥ 1 ticks, and the median tick load on infested chicks was two in both species. Infestation rates varied by a factor of about two among years (0.42 to 0.87 overall), but were uncorrelated between species and with air temperatures over the preceding winter. The probability of hosting a tick declined strongly with chick age, mainly in the first 20 days after hatching, and to near zero by fledging. Asymptotic weights and/or wing lengths declined with tick load in both species, but at normal loads the reductions were minor relative to those imposed by other factors; only at very high loads, which were rare, were effects likely to be biologically relevant. Tick load and survival to fledging were unrelated in both species. While our study found little influence of ticks, we believe there is need for further study of the relationships between parasites and seabird demography, especially in light of ongoing environmental change.