Ticks and Tick-borne Diseases最新文献

{"title":"Midgut-specific vitellogenin-1 is involved in the negative regulation of Babesia ovata migration or proliferation in Haemaphysalis longicornis tissues","authors":"Nariko Sato,&nbsp;Rika Umemiya-Shirafuji","doi":"10.1016/j.ttbdis.2025.102480","DOIUrl":"10.1016/j.ttbdis.2025.102480","url":null,"abstract":"<div><div>Transovarial transmission of bovine <em>Babesia</em> has been experimentally demonstrated using larvae from <em>Haemaphysalis longicornis</em> ticks that are parasitized on cattle infected with <em>Babesia ovata</em>. However, the molecular mechanisms underlying this transovarial transmission remain unclear. We previously showed that vitellogenin (Vg) and its receptor, essential for oogenesis, are key factors involved in <em>Babesia</em> infection in the ovary of <em>H. longicornis</em>. So far, three <em>Vg</em> genes (<em>HlVg-1, HlVg-2</em>, and <em>HlVg-3</em>) have been identified from <em>H. longicornis</em>, but the roles of Vgs other than HlVg-2 in <em>Babesia</em>-infected ticks are unknown. Here, we report the estimated roles of midgut-specific <em>HlVg-1</em> in <em>Babesia</em>-infected ticks. Following semi-artificial feeding of <em>B. ovata</em>-infected bovine red blood cells, the expression level of <em>HlVg-1</em> was significantly upregulated at 1 and 2 days after engorgement (dAE). Subsequently, gene silencing mediated via RNA interference (RNAi) was performed to infer the role of <em>HlVg-1</em> in <em>B. ovata</em>-infected ticks. Interestingly, relative detection levels of <em>Babesia</em> DNA in <em>HlVg-1</em> RNAi ticks were higher compared with control ticks at 1 and 2 dAE. These results indicate that <em>HlVg-1</em> might regulate tissue-to-tissue migration or proliferation of <em>Babesia</em> in the tick body. Our data hypothesize that each organ-specific Vg has individual roles during <em>Babesia</em> infection.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"16 3","pages":"Article 102480"},"PeriodicalIF":3.1,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143844505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficacy of rodent pathogen reservoir-targeted topical acaricide treatment strategies to lower the density of host-seeking Ixodes pacificus nymphs in California","authors":"Newton Maxwell ,&nbsp;Nakano Angie ,&nbsp;Summers Shannon ,&nbsp;Esquivel Alexander ,&nbsp;Swei Andrea","doi":"10.1016/j.ttbdis.2025.102479","DOIUrl":"10.1016/j.ttbdis.2025.102479","url":null,"abstract":"<div><div>Lyme disease, caused primarily by the bacterium <em>Borrelia burgdorferi</em> sensu stricto (s.s.), is the most prevalent vector-borne disease in the United States. Lyme disease spirochetes are maintained through enzootic cycles of pathogen transmission between vertebrate reservoir hosts and tick vectors. Reservoir host targeted strategies have been examined for their ability to disrupt enzootic transmission cycles of <em>B. burgdoferi</em> s.s. within natural environments in the eastern U.S. However, there are no studies in the western U.S. examining the effect of permethrin- and deltamethrin-based topical acaricides on <em>Ixodes pacificus</em> over consecutive years of treatment. We evaluated rodent reservoir-targeted topical acaricide treatments from 2023 to 2024 in California and examined their impact on larval <em>I. pacificus</em> infesting rodent host species and the density of host-seeking nymphal <em>I. pacificus</em>. Modified bait stations contained topical acaricides to treat dusky-footed woodrats (<em>Neotoma fuscipes</em>), western gray squirrels (<em>Sciurus griseus</em>), and several <em>Peromyscus</em> species throughout the peak of larval and nymphal <em>I. pacificus</em> host-seeking activity between March and May. Topical acaricide treatments including permethrin and deltamethrin were applied on three replicate plots. Our results show that larval <em>I. pacificus</em> burdens decreased by 96 % at acaricide treated plots compared to control plots in 2024. In addition, the density of host-seeking nymphal <em>I. pacificus</em> was 56 % lower at acaricide treated plots compared to control plots in 2024. This suggests that in the western U.S., host-targeted topical acaricide treatments are a highly effective strategy for reducing rodent reservoir-attached ticks as well as the abundance of host-seeking nymphal <em>I. pacificus</em>.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"16 3","pages":"Article 102479"},"PeriodicalIF":3.1,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143825384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Limited occurrence of Borrelia burgdorferi sensu lato in the European hedgehog (Erinaceus europaeus) and Ixodes hexagonus in Great Britain","authors":"Marco Vecchiato ,&nbsp;Becki Lawson ,&nbsp;Katharina Seilern-Moy ,&nbsp;Mia L. White ,&nbsp;Nicola Jones ,&nbsp;Faye Brown ,&nbsp;Dylan Yaffy ,&nbsp;Jolyon M. Medlock ,&nbsp;Kayleigh M. Hansford","doi":"10.1016/j.ttbdis.2025.102475","DOIUrl":"10.1016/j.ttbdis.2025.102475","url":null,"abstract":"<div><div><em>Borrelia burgdorferi</em> sensu lato (<em>Bb</em>sl) are multi-host bacteria and the causative agents of the zoonotic disease, Lyme borreliosis, for which <em>Ixodes</em> spp. are the vectors. In Great Britain (GB), research to date has primarily focussed on <em>Ixodes ricinus</em> as the main tick transmitting this pathogen, while the role that the European hedgehog (<em>Erinaceus europaeus</em>) and the hedgehog tick (<em>Ixodes hexagonus</em>) might have in the transmission cycle requires investigation. This study aimed to examine the occurrence of <em>Bb</em>sl infection in hedgehogs and <em>I. hexagonus</em> in GB; to characterise the species if present; and to better inform our understanding of these species as potential hosts or vectors. Post-mortem examinations have been conducted on hedgehogs found dead from across GB over the period 2013–2022 inclusive. We collated the available convenience sample archive from 96 hedgehogs for which both frozen ear tissue and <em>Ixodes</em> spp. (comprising 563 <em>I. hexagonus</em>, 18 <em>I. ricinus</em> and one <em>Ixodes frontalis</em>) in 70 % ethanol were available. Supplementary tissue samples were analysed from the hedgehogs where either ear tissue or ticks tested <em>Borrelia</em> DNA-positive, to investigate whether the infection was localised or disseminated. An additional 86 <em>I. hexagonus</em> collected from 14 hedgehogs with no ear tissue available were included to increase the sample size<em>.</em> DNA from tissue and tick samples was tested using a pan-<em>Borrelia</em> qPCR assay. Only 4.2 % (4/96) of hedgehogs and 1.2 % (4/335 total: 0.6 %, 2/329 <em>I. hexagonus</em>; 40 %, 2/5 <em>I. ricinus</em>) of tick pools were qPCR-positive suggesting that <em>Bb</em>sl infrequently circulate in hedgehog and <em>I. hexagonus</em> in GB. Therefore, both species may play a limited role in wider transmission cycles in this country. <em>Borrelia afzelii</em> was the sole species characterised by subsequent sequence analysis in both hedgehogs and ticks, providing some evidence of host-vector interaction at larval and nymph life stages, as all the positive ticks were collected from <em>B. afzelii</em> DNA-positive hedgehogs. Histopathological examination of hedgehog tissues found no evidence of borreliosis and therefore no clinical significance of <em>B. afzelii</em> infection to hedgehog health. The low occurrence of <em>B. afzelii</em> detected in <em>I. hexagonus,</em> combined with the lower frequency of human biting behaviour of <em>I. hexagonus</em> when compared with <em>I. ricinus,</em> suggests that the public health risk of infection from <em>I. hexagonus</em> bites is lower than for <em>I. ricinus.</em> Notably, our dataset found minimal co-feeding of these tick species on hedgehog hosts in contrast to studies in mainland Europe, which could influence pathogen dynamics in GB.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"16 3","pages":"Article 102475"},"PeriodicalIF":3.1,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143777507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reevaluating the presence of Rhipicephalus australis (Acari: Ixodidae) in Southeast Asia: A phylogenetic approach based on Cambodian tick samples","authors":"Didot Budi Prasetyo ,&nbsp;Sony Yean ,&nbsp;Sébastien Boyer","doi":"10.1016/j.ttbdis.2025.102478","DOIUrl":"10.1016/j.ttbdis.2025.102478","url":null,"abstract":"<div><div>Morphological variability between <em>Rhipicephalus australis</em> and <em>R. microplus</em> has led to taxonomic ambiguity, leading to species misidentification. <em>Rhipicephalus australis</em> is reported to have a distribution range in Pacific Ocean region extending to several Southeast Asian countries, including Cambodia, although its presence in continental Southeast Asia has not been supported by molecular data. With growing evidence of conflicting morphological characters, this study aimed to evaluate the presence of <em>R. australis</em> in Cambodia using both morphological and molecular identification. Tick specimens were collected from cattle across 21 provinces of Cambodia, and a subset of 95 <em>R. microplus</em> complex (37 morphologically identified as <em>R. australis</em>, 39 <em>R. microplus</em>, and 19 nymphs) was selected for molecular analysis. DNA barcoding of the cox1 gene was performed, and a maximum likelihood phylogenetic tree revealed that all specimens clustered within <em>R. microplus</em> clade A. These findings, along with previous observations from other regions, suggest that, in the absence of molecular data, there is no definitive evidence to support the presence of <em>R. australis</em> in continental Southeast Asia, particularly in Cambodia.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"16 3","pages":"Article 102478"},"PeriodicalIF":3.1,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143777505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of tick infestation in the progression of Anaplasma phagocytophilum infection in lambs","authors":"M. Groenevelt ,&nbsp;S.R. Wijburg ,&nbsp;H. Sprong ,&nbsp;K. Kerkhof ,&nbsp;S. Stuen","doi":"10.1016/j.ttbdis.2025.102477","DOIUrl":"10.1016/j.ttbdis.2025.102477","url":null,"abstract":"<div><div>Tick Borne Fever (TBF) is a serious health condition in sheep, caused by infection with <em>Anaplasma phagocytophilum</em>. When secondary bacterial infections occur in TBF, it can progress to tick pyemia, a condition causing severe morbidity and mortality in flocks. The mechanisms that underly the severe effects of tick pyemia are not fully understood. Here, we hypothesized that tick bites during an established <em>A. phagocytophilum</em> bacteremia could aggravate immunosuppression, increasing the risk of secondary infections. In this study, four groups of four lambs were compared based on their clinical and hematological outcomes. Group A received an intravenous injection of <em>A. phagocytophilum</em> on day 0. Group AT received the same injection on day 0, followed by tick placement on their backs on day 4. Group T was exposed only to tick placement on day 4, while Group C received no treatment. The animals were clinically and hematologically assessed over 28 days, and ticks collected off their backs after feeding were analyzed. Both clinically and hematologically, no additional detrimental effects were seen in Group AT compared to Group A. All lambs in Group T also developed TBF, but their clinical and hematological outcomes were less severe than those in Groups A and AT. Serologically, all animals responded similarly, corresponding to the day of exposure to <em>A. phagocytophilum</em>. PCR results showed no significant differences among groups, although duration of follow-up may have influenced the results, as only Group AT lambs remained PCR positive on the final testing day. When ticks that fed on Group AT lambs were compared to either ticks fed on Group T lambs or unengorged ticks harvested from the same fields, it became clear that sheep act as amplifier hosts for <em>A. phagocytophilum</em> in ticks shortly after exposure to infected ticks<em>.</em> Among the unengorged ticks, 10.2 % were infected with <em>A. phagocytophilum</em>, compared to 67 % and 99.2 % of the engorged ticks from Groups T and AT, respectively. In contrast to <em>A. phagocytophilum</em>, sheep were refractory hosts for <em>Borrelia burgdorferi</em> s.l., as the percentage of infected ticks was 10.2 % in the unengorged ticks and only 1 and 1.7 % in engorged ticks from groups T and AT, respectively. In this study, additional tick bites did not contribute to immunosuppression in lambs during an established <em>A. phagocytophilum</em> bacteremia.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"16 3","pages":"Article 102477"},"PeriodicalIF":3.1,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143698133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Plasma levels of the neuron damage markers brain-derived tau and glial fibrillary acidic protein in Lyme neuroborreliosis: A longitudinal study","authors":"Mathilde Ørbæk ,&nbsp;Fernando Gonzalez-Ortiz ,&nbsp;Rosa M.M. Gynthersen ,&nbsp;Åse Bengaard Andersen ,&nbsp;Kubra Tan ,&nbsp;Ulf Andreasson ,&nbsp;Kaj Blennow ,&nbsp;Helene Mens ,&nbsp;Henrik Zetterberg ,&nbsp;Anne-Mette Lebech","doi":"10.1016/j.ttbdis.2025.102459","DOIUrl":"10.1016/j.ttbdis.2025.102459","url":null,"abstract":"<div><h3>Background</h3><div>A reliable blood biomarker for neuroborreliosis (NB) has yet to be identified. This study investigated levels of neuron damage markers glial fibrillary acidic protein (GFAP) and brain-derived tau (BD-tau) over six months of follow-up in patients with NB. The aim was to evaluate the potential of these biomarkers for monitoring treatment response and prognostic purposes.</div></div><div><h3>Methods</h3><div>A retrospective longitudinal cohort study including plasma collected at diagnosis and approximately three- and six-months post diagnosis from adult NB patients enrolled at the Department of Infectious Diseases, Rigshospitalet between 2018 and 2020.</div><div>BD-tau concentrations were measured in-house using the Single Molecule Array (Simoa) HD-X platform, while GFAP concentrations were assessed on the same platform utilizing the GFAP Discovery Kit. Changes in biomarker concentrations were analyzed using linear mixed models with an unstructured covariance pattern, with follow-up included as a categorical fixed effect.</div></div><div><h3>Results</h3><div>A total of 23 patients (median age: 63 years; male/female ratio: 16/7) with 56 plasma samples were analyzed; 12 patients had complete samples. GFAP and BD-tau levels showed minimal variation throughout the study period. Patients with persistent symptoms had GFAP concentrations that were 55 % higher at diagnosis compared to those who fully recovered, though this difference was not statistically significant (<em>p</em> = 0.09). No significant associations were observed between biomarker levels and treatment response or long-term outcomes.</div></div><div><h3>Conclusions</h3><div>This longitudinal study did not find BD-tau or GFAP to be effective blood biomarkers for monitoring treatment response or predicting outcomes in NB.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"16 3","pages":"Article 102459"},"PeriodicalIF":3.1,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143687778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Borrelia spp. and Anaplasma phagocytophilum in ruminant ticks – Borrelia prevalence declines only in female, but not nymphal ticks feeding on cervids","authors":"Andrea Springer ,&nbsp;Gökben Özbakış-Beceriklisoy ,&nbsp;Anna-Katharina Topp ,&nbsp;Julia Probst ,&nbsp;Volker Fingerle ,&nbsp;Christina Strube","doi":"10.1016/j.ttbdis.2025.102476","DOIUrl":"10.1016/j.ttbdis.2025.102476","url":null,"abstract":"<div><div>Tick-borne pathogen epidemiology involves vectors, in Europe mainly <em>Ixodes ricinus</em>, and vertebrate hosts. Ruminants are reservoirs for <em>Anaplasma phagocytophilum</em>, but not for <em>Borrelia burgdorferi</em> sensu lato (s.l.), possibly clearing the infection from ticks. However, such clearance is epidemiologically relevant mainly in nymphal ticks. Of 1874 ticks collected from wildlife in the present study, 1535 <em>Ixodes</em> spp. (796 nymphs, 739 females) were tested by qPCR, with a proportion of 26.3% (nymphs: 24.5%, females: 28.3%) positive for <em>Borrelia</em> spp. and 87.4% for <em>A. phagocytophilum</em> (nymphs: 62.8%, females: 92.4%). In female <em>Ixodes</em> spp. from deer (N = 720), but not nymphs (N = 785), the <em>Borrelia</em> frequency declined significantly with increasing engorgement duration as inferred by the coxal index. <em>Borrelia</em> spp. differentiation revealed <em>B. burgdorferi</em> s.l. in nine and <em>B. miyamotoi</em> in one of ten successfully analysed ticks having engorged for &lt;48 hours, but only three <em>B. burgdorferi</em> s.l.- <em>vs.</em> six <em>B. miyamotoi</em>-positive and one coinfected tick among ten ticks with a longer engorgement. <em>Borrelia</em> copy numbers showed a U-shaped relationship with engorgement duration. Increasing <em>A. phagocytophilum</em> frequency during the rapid feeding phase in nymphs, and increasing copy numbers in females from deer confirmed their reservoir function. Of 101 <em>I. ricinus</em> from cattle, 4.0% were positive for <em>Borrelia</em>, whereby the species could not be determined, and 42.6% for <em>A. phagocytophilum</em>. In comparison, 13.8% and 11.9% of 428 questing ticks from the pastures were <em>Borrelia</em>- and <em>A. phagocytophilum</em>-positive, respectively. The results imply that feeding on cervids may not reduce <em>Borrelia</em> prevalence in nymphs, presumably due to the low overall blood volume ingested, insufficient for <em>Borrelia</em> clearance in this epidemiologically relevant stage. Further studies need to confirm that deer-fed nymphs contain infectious <em>Borrelia</em> and maintain the infection transstadially.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"16 3","pages":"Article 102476"},"PeriodicalIF":3.1,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143687779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prevalence of Rickettsia species phylotype G022 and Rickettsia tillamookensis in Ixodes pacificus nymphs and adults from Northern California","authors":"Erin Trent ,&nbsp;Andrea Swei ,&nbsp;Tina Feiszli ,&nbsp;Megan E.M. Saunders ,&nbsp;Jianmin Zhong","doi":"10.1016/j.ttbdis.2025.102463","DOIUrl":"10.1016/j.ttbdis.2025.102463","url":null,"abstract":"<div><div>Ticks are known vectors of various pathogenic bacteria, including species of <em>Rickettsia</em>. Two novel <em>Rickettsia</em> species have been identified in adult <em>Ixodes pacificus: Rickettsia</em> species phylotype G022 in 2011 and <em>R. tillamookensis</em> in 2021. Currently, the pathogenic potential of these species found in <em>I. pacificus</em> remains unknown. This study aimed to determine the prevalence of phylotype G022 and <em>R. tillamookensis</em> in <em>I. pacificus</em> nymphs across different mean annual temperature and relative humidity zones in California. Adult ticks were also tested for phylotype G022. Ticks were collected from multiple locations in seven northern California counties and tested by real-time PCR. The overall prevalence of phylotype G022 and <em>R. tillamookensis</em> in nymphs (<em>n</em> = 550) was 5.3 % (95 % CI = 3.7 %-7.5 %) and 1.6 % (95 % CI=0.8 %–3.3 %), respectively. The overall prevalence of phylotype G022 in adult <em>I. pacificus</em> (<em>n</em> = 720) was 9.0 % (95 % CI = 7.2 %-11.3 %). Phylotype G022 infects nymphal <em>I. pacificus</em> across a broad geographic range. The prevalence of phylotype G022 was higher in the 11.7–13.3 °C (53–56°F) temperature zone, at 6.4 % (95 % CI = 4.5 %-9.2 %), compared to the 13.9–15 °C (57–59°F) zone, where the prevalence was 0.8 % (95 % CI = 0.2 %-4.6 %). In contrast, the prevalence of <em>R. tillamookensis</em> did not show a statistically significant difference between the two temperature zones, with 1.9 % (95 % CI = 0.9 %-4.1 % in the 11.7–13.3 °C (53–56°F) zone and 0.9 % (95 % CI = 0.2 %-4.9 %) in the 13.9–15 °C (57–59°F) zone. The detection of phylotype G022 in both questing nymphs and adults of <em>I. pacificus</em> suggests that it is transmitted transstadially. qPCR testing revealed no coinfections of G022 and <em>R. tillamookensis</em> in any of the nymphs. Although <em>R. tillamookensis</em> exhibited a lower overall prevalence in nymphs compared to phylotype G022, both bacteria exhibited a similar geographic distribution.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"16 3","pages":"Article 102463"},"PeriodicalIF":3.1,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143671416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Linked empirical studies reveal the cumulative impact of acquired tick resistance across the tick life cycle","authors":"J.P. Owen ,&nbsp;A. Gibbs ,&nbsp;C.R. Jones ,&nbsp;J.L. Brunner ,&nbsp;K. Mason ,&nbsp;S.M. Noh ,&nbsp;G.A. Scoles","doi":"10.1016/j.ttbdis.2025.102460","DOIUrl":"10.1016/j.ttbdis.2025.102460","url":null,"abstract":"<div><div>Host defenses affect tick feeding success, and thus survival and reproduction, but defensive traits have rarely been studied relative to tick population dynamics. We explored the effects of anti-tick resistance of three natural hosts against <em>Dermacentor andersoni,</em> the Rocky Mountain wood tick. Larval ticks were fed on Deer mice (<em>Peromyscus maniculatus</em>) and Cottontail rabbits (<em>Sylvilagus nuttallii</em>), and nymph and adult ticks were fed on cattle (<em>Bos taurus</em>). We compared feeding success and fecundity of ticks fed on naïve (never infested by ticks) or exposed (one prior tick infestation) hosts. We used these measures to parameterize simulations of <em>D. andersoni</em> population growth in a discrete time, geometric population model to understand the population-level consequences of anti-tick resistance. Prior infestation triggered tick resistance in all three host species and impacted all tick life stages. On tick-exposed hosts, an average of 23 % fewer ticks reached adulthood and adult females produced 32 % fewer larvae. Modest effects of tick resistance at each life stage had strong cumulative effects across the tick life cycle. Simulated tick population dynamics revealed that mean population growth (<span><math><mi>λ</mi></math></span>) is reduced 68 % when the life cycle is completed on hosts with prior tick exposure. Simulated populations feeding on exposed hosts were more likely to decline (<span><math><mi>λ</mi></math></span>&lt;1) under conditions of low off-host survival and host-finding. This suggests acquired tick resistance may interact with environmental conditions and host availability to affect tick population dynamics. These data shed new light on naturally occurring biotic factors that may affect tick abundance and tick-borne pathogen transmission.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"16 3","pages":"Article 102460"},"PeriodicalIF":3.1,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143671412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ehrlichia ruminantium (Ehrlichiaceae) infection rates and genotyping in Amblyomma species from southern Africa","authors":"Andeliza Smit ,&nbsp;Fernando C. Mulandane ,&nbsp;Stephane H. Wójcik ,&nbsp;Choolwe Malabwa ,&nbsp;Gourgelia Sili ,&nbsp;Stephen Mandara ,&nbsp;Kaïssa Plaisir Pineau ,&nbsp;Sylvie Lecollinet ,&nbsp;Antoni Exbrayat ,&nbsp;Valérie Rodrigues ,&nbsp;Hannah Rose Vineer ,&nbsp;Zinathi Dlamkile ,&nbsp;Wilhelm H. Stoltsz ,&nbsp;Damien F. Meyer ,&nbsp;Darshana Morar-Leather ,&nbsp;Benjamin L. Makepeace ,&nbsp;Luis Neves","doi":"10.1016/j.ttbdis.2025.102462","DOIUrl":"10.1016/j.ttbdis.2025.102462","url":null,"abstract":"<div><div>Ticks are haematophagous ectoparasites of domestic and wild animals. With their vast geographical distribution and aptitude as vectors of a large variety of pathogens, they are ranked amongst the top two arthropod families of veterinary and medical concern. <em>Amblyomma</em>, the third largest genus in the Ixodidae, is important in southern Africa due to its vector competence for <em>Ehrlichia ruminantium</em> and other pathogens. <em>Ehrlichia ruminantium,</em> the causative agent of heartwater, a potentially lethal disease in ruminants, is classified as a notifiable disease by the World Organisation for Animal Health. <em>Amblyomma</em> species ticks were collected in five southern African countries from livestock and wildlife. They were morphologically identified to species level with taxonomic keys, and species identity was confirmed with molecular assays. Preliminary screening for <em>E. ruminantium</em> was conducted by targeting the pCS20 gene fragment. Genotyping of 39 <em>E. ruminantium</em> positives was obtained using Ampliseq technology. In total, 7,734 <em>Amblyomma</em> ticks were collected and identified as belonging to four species: <em>Amblyomma eburneum, Amblyomma hebraeum, Amblyomma pomposum</em> and <em>Amblyomma variegatum. Ehrlichia ruminantium</em> infection rates per country ranged from 7.1 % to 34.1 %. The genotyping analysis indicated the clustering of our sequences with strains Gardel, Welgevonden, Um Banein, Springbokfontein 4 and 2, Kwanyanga, and Blaauwkrans. The Ampliseq analysis was not effective in differentiating between strains found in southern Africa. This large study documents the genetic diversity and prevalence of <em>E. ruminantium</em> in ticks across southern Africa, highlighting implications for disease control and vaccine development.</div></div>","PeriodicalId":49320,"journal":{"name":"Ticks and Tick-borne Diseases","volume":"16 3","pages":"Article 102462"},"PeriodicalIF":3.1,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143642576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}