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Ticks and Tick-borne Diseases

Elsevier BV

Preprints posted in the last 30 days, ranked by how well they match Ticks and Tick-borne Diseases's content profile, based on 11 papers previously published here. The average preprint has a 0.01% match score for this journal, so anything above that is already an above-average fit.

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Ticks and tickborne diseases in the upper Midwestern United States: role for citizen science in assessing exposure risk

Linz, A. M.; Marcis, C.; Payant, C.; Donnerbauer, L.; Donnerbauer, A.; Gruenling, E.; Boese, K.; Heuer, G.; Boehm, A.; Uelmen, J. A.; Fritsche, T. R.; Meece, J. K.

2026-05-15 microbiology 10.64898/2026.05.14.724901 medRxiv
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Tickborne diseases are a significant burden in many parts of the world. In the upper Midwestern United States, Lyme disease is the most common tickborne disease. It is carried by Ixodes scapularis. This vector can also transmit the pathogens causing anaplasmosis, babesiosis, ehrlichiosis, and several more tickborne diseases in this region. There is also concern for other tick species, such as Amblyomma americanum, that are expanding their ranges northward. We launched a citizen science passive tick surveillance program in 2024 to investigate tick species ranges in the upper Midwest, as well as the pathogens carried by I. scapularis. We received over 12,000 ticks in the first two years of this program, primarily from Wisconsin. While we received submissions of adult A. americanum outside of their endemic range, we did not see evidence of establishment in our study area. We measured pathogen prevalence in adult female I. scapularis (n=707) and observed 51% positivity for Borrelia burgdorferi, 9% for Babesia microti, 9% for Anaplasma phagocytophilum, and 3% for Ehrlichia muris eauclairensis. Multiple pathogens were identified in 14% of tested specimens, and significant associations were observed between B. burgdorferi and B. microti, and B. burgdorferi and E. muris eauclairensis. Pathogen prevalences varied across time and geography. Our results can begin to inform risk assessment for tickborne diseases in our region. A non-technical version of this document with interactive maps is available here: https://storymaps.arcgis.com/stories/8008c9d710b5400599f3c6cf88b2c546 Our online data dashboard is available here: redcap.link/TICS

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Development and validation of a multilocus sequence typing scheme for Fasciola hepatica using next-generation deep amplicon sequencing

Abbas, M.; kozel, K.; Daramola, O.; Selemetas, N.; Robinson, M. W.; Morgan, E. R.; Chaudhry, U.; Betson, M.

2026-05-22 genetics 10.64898/2026.05.20.726500 medRxiv
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Fasciolosis caused by Fasciola hepatica is an economically important disease in sheep and cattle. Knowledge of the population genetic structure of F. hepatica is important for understanding gene flow and informing disease control. In the present study, we designed, developed, and validated a multilocus sequence typing (MLST) scheme based on six markers. These markers were selected by aligning newly sequenced whole-genome sequence (WGS) data with available reference genomes and selecting variable regions with five or more single-nucleotide polymorphisms SNPs from different scaffolds of the F. hepatica reference genome Fasciola 10x pilon (GCA_900302435.1). Twenty markers were initially identified, of which 12 were multiplexed for deep amplicon sequencing after validation on worm and faecal eggs DNA; six markers were ultimately retained for downstream population genetics analysis. These markers were used to investigate population genetic structure in 15 cattle- and 27 sheep-derived F. hepatica populations in UK. A total of 53 unique alleles from six MLST markers were identified from 30 faecal (cattle = 13, sheep = 17) and 12 adult worm (cattle = 2, sheep = 10) populations. Shared alleles were observed in sheep- and cattle-derived populations. The highest allelic variation was observed in the Scottish Borders, Southern Scotland, and South-West England, and the lowest in North-West England. Minimal genetic differentiation was observed between cattle- and sheep-derived populations, with most genetic structuring within rather than between populations. Five markers showed high allelic polymorphism, whereas one marker showed low levels of allelic polymorphism, highlighting the importance of multilocus approaches. Overall, this six MLST-marker panel provides a tool for population genetic studies, revealing high gene flow and clonal expansion of F. hepatica across hosts and regions in the UK.

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Effects of Llama-Derived Hyperimmune Serum on Motility and Viability of Echinococcus granulosus Protoscoleces

FERNANDEZ SALOM, M. J.; CARABAJAL, M. P. A.; DI LULLO, D.; VILLA MICO, H. D.; FORMENTINI, E. A.; Cantero, M. D. R.; Cantiello, H. F.

2026-05-04 immunology 10.64898/2026.04.30.721736 medRxiv
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Cystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus, remains a significant public health and veterinary problem in endemic regions. Although chemotherapy and control programs exist, the development of complementary immunotherapeutic tools is increasingly needed. This study evaluated the generation and functional activity of hyperimmune serum (HIS) produced in three adult male castrated llamas (Lama glama) immunized with antigenic material derived from protoscoleces (PSCs) of the parasite. Sera collected after each of the first six immunizations were assessed by ELISA to quantify antigen-specific IgG responses, and their biological effects were tested in vitro using viable PSCs. Motility was measured using video-assisted paired-image scoring across serial serum dilutions (1:2-1:2048), and the methylene blue exclusion assay was used to assess viability. Hyperimmune serum produced a clear, reproducible, dose-dependent inhibition of PSC motility and viability. Higher titers of early inoculations reduced motility by 70-85%, while sera from the fifth and sixth inoculations achieved complete suppression. Naive serum and PBS controls showed no inhibitory effect. ELISA titers strongly correlated with biological activity, indicating that higher humoral responses predicted functional inhibition. These findings demonstrate the feasibility of generating potent anti-Echinococcus granulosus polyclonal antibodies in camelids and support their potential application in passive immunization strategies. The study establishes a foundation for future development of llama-derived immunobiological reagents, including nanobody-based tools, for the control of cystic echinococcosis.

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Suspected rabies exposure among animal-bite human cases in Busia district, Uganda: Prevalence, associated factors and delayed post-exposure care-seeking. A cross-sectional study

Wagaba, D.; Nabukenya, I.; Kizza, J.; Unith, H.; Kanyange, A.; Turyahabwe, C.; Kibuuka, H.; Mugisha, D.; Ogola, S. P.; Nabidda, S.; Kisakye, L. K.; Kalyango, J.

2026-06-01 epidemiology 10.64898/2026.05.29.26354408 medRxiv
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Background Rabies is a zoonotic neglected public health problem associated with animal bites, especially domestic carnivores claiming 59,000 deaths annually predominantly in developing countries of Africa and Asia. There is a high risk of exposure among rural communities endemic with animal rabies where adoption of prevention strategies is minimal. This study determined the prevalence of suspected rabies exposure, associated factors, and delayed post-exposure care-seeking among animal-bite human cases in Busia district, Uganda. Methods: This was a cross-sectional study that involved 332 consecutively sampled animal bite human cases that occurred within the period 2023 to 2024. Data for the bite cases from records were collected using a data abstraction tool. In addition, interviewer-administered semi-structured questionnaires were used to collect data on sociodemographic, animal-related and environmental characteristics. Approximate bite locations were collected using Global Positioning System (GPS) coordinates via Kobo collect. Analysis was carried out in STATA 17 using mixed effects modified Poisson regression for factors associated with suspected rabies exposure. Results: The median age of the bite cases was 18 (IQR: 9-36) with the male gender predominantly affected. The prevalence of suspected rabies exposure was 53.6% (95% Confidence interval - CI: 46.8-60.3). Factors associated were urban versus (vs) rural residence (adjusted prevalence ratio-aPR: 1.04, 95%CI: 1.00-1.08), being bitten by a stray animal (aPR: 1.28, 95% CI: 1.22-1.35) and wild animal (aPR: 1.22, 95% CI: 1.14-1.30) vs domestic animal, vaccination status of the biting animal i.e. vaccinated vs unvaccinated (aPR: 0.76, 95% CI: 0.69-0.85), provoked vs unprovoked bites (aPR: 0.82, 95% CI: 0.79-0.86), and distance to nearest river ([&ge;]5km) vs <5km (aPR: 0.93, 95% CI: 0.87-0.99). The prevalence of delayed post-exposure seeking was 23.0% (95% CI: 16.5-31.1) among the suspected rabies exposures. Conclusion: The study reveals a high prevalence of suspected rabies exposure. Factors associated are multidimensional i.e. are of human, animal and environmental origin. The one health paradigm should be emphasized during routine surveillance of rabies-related cases. The study observed that 1 in 5 bite cases delayed to seek care post bite exposure. We recommend collaborations between sectors, routine vaccination and awareness campaigns, and monitoring of wild carnivore populations and environmental dynamics in rabies-related surveillance.

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Genome-wide CRISPR knockout cell screening platform for the disease vector tick species Ixodes scapularis

Butnaru, M.; McKenna, W.; Goswami, S.; Wu-Chuang, A.; Mameli, E.; Wilcox, A.; Quennesson, L.; Kim, A.-R.; Veal, A.; Chen, W.; Verzone, H.; Lane, E. A.; Laukaitis-Yousey, H. J.; Araneo, C.; Singh, N.; Pedra, J.; Hu, Y.; Viswanatha, R.; Perrimon, N.; Mohr, S. E.

2026-05-07 genetics 10.64898/2026.05.05.721418 medRxiv
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The black legged tick, Ixodes scapularis, is a vector of the bacterium that causes Lyme disease and several other illnesses, including anaplasmosis, babesiosis, and tick-borne encephalitis. Although high-quality genome annotations are available for I. scapularis, functional understanding of I. scapularis genes is limited. To address this, we developed a platform for genome-wide CRISPR-Cas9 knockout screening in I. scapularis cells. To evaluate the platform, we performed a screen to identify genes associated with cellular fitness, and screens for resistance to treatment with copper chloride, Antimycin A, or Destruxin A (DA), a cyclic hexadepsipeptide produced by the pathogenic fungus Metarhizium anisopliae. In each case, the screens implicate specific sets of conserved and non-conserved I. scapularis genes in relevant cellular functions, providing the first experimental evidence of function for a large set of I. scapularis genes. Altogether, in this first-of-its-kind effort for the arthropod subclass Acari, we present an unbiased genome-wide CRISPR-Cas9 knockout cell screening platform, related resources, and datasets that will be broadly useful to efficiently uncover cellular functions of I. scapularis genes.

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Description of Rickettsia senegalensis sp. nov.: a new Rickettsia species detected worldwide

Labarrere, C.; Houmenou, C. T.; Fournier, P.-E.; Fenollar, F.; Mediannikov, O.

2026-05-05 microbiology 10.64898/2026.05.02.721834 medRxiv
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Rickettsia senegalensis is a novel Rickettsia species isolated from cat fleas, Ctenocephalides felis, in Senegal. Genomic analysis confirmed its status as a distinct species, placing it within the transitional Rickettsia group, within a R. felis cluster. Furthermore, rickettsial genes identical to those of Rickettsia senegalensis had been already identified in several hematophagous arthropods, including fleas and ticks parasitizing various hosts such as cats, dogs, opossums, and rodents in tropical and subtropical regions all over the world. It has also been detected in cat tissues, suggesting a potential host-pathogen association. Here we formally propose Rickettsia senegalensis sp. nov. as a new species. The type strain of this species is strain PU01-02T (= CSUR R184T = DSM 28250T). Strain PU01-02T grows aerobically in XTC-2, SF9, and LD652 cell lines at 28 {degrees}C in a CO2-free atmosphere. The genome of strain PU01-02T has a size of 1.62 Mb and a G+C content of 33.2%. RepositoriesThe genome sequence of Rickettsia senegalensis sp. nov. strain PU01-02T has been deposited in GenBank under accession number JBVYTQ000000000, and the rrs, gltA, ompB and sca4 gene sequences under accession numbers KF666476, KF666472, KF666470, KF666474, respectively. The plasmid accession numbers are PZ272915, PZ272916, and PZ272917, for pRS01, pRS02 and pRS03, respectively.

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Climatic suitability for leishmaniasis at global and European scales

Charnley, G. E. C.

2026-05-20 epidemiology 10.64898/2026.05.19.26353551 medRxiv
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Leishmaniasis, a climate-sensitive zoonotic neglected tropical disease, is transmitted by Phlebotomine sand flies and closely linked to socio-economic inequities. Understanding its spatio-temporal dynamics under environmental and social change is critical for effective control. A machine learning framework (XGBoost) was developed to map the global and European distribution of leishmaniasis, incorporating climatic indicators, land cover, elevation, and socio-economic indices (Human Development Index, AROPE). For Europe, five proven vector species (Phlebotomus perniciosus, P. ariasi, P. perfiliewi, P. neglectus, and P. tobbi) were modelled alongside cutaneous and visceral leishmaniasis. Across both analyses, land use features, particularly shrubland and forest cover, had the greatest explanatory power, reflecting their role in providing microclimates and vertebrate hosts for sand flies. Climatic factors, notably mean temperature of the coldest quarter and humidity of the warmest/driest quarters, were also influential, as these facilitate sand fly survival. Socio-economic predictors consistently improved model performance, confirming the role of poverty and inequity as determinants of disease distribution. Globally, leishmaniasis risk increased by ~17% since the 1990s, with Africa, Asia, and the Americas experiencing the greatest rise. In Europe, modest continental-scale increases (CL +1.28%; VL +2.47%) masked strong sub-national heterogeneity, including northward expansion of visceral leishmaniasis and increases in cutaneous leishmaniasis in southern and eastern regions. Sand fly projections indicated expansion of warm-adapted species (P. ariasi, P. perniciosus, P. neglectus) and contraction of species preferring cooler, more humid niches (P. perfiliewi, P. tobbi). These findings highlight climate change, land use, and inequity as interacting drivers of leishmaniasis, emphasising the need for enhanced surveillance, integrated vector management, and targeted support for vulnerable populations, including refugees and migrants.

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Widespread circulation of West Nile and Usutu viruses in sedentary and migratory avifauna: A Two-Year Study (2024-2025) of active surveillance in South of France

Beaubaton, R.; Revel, J.; Pigeyre, L.; Lepeule, A.; Joly, J.; de Franceschi, C.; Charmantier, A.; Vollot, B.; Simonin, Y.

2026-05-21 microbiology 10.64898/2026.05.21.726855 medRxiv
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West Nile virus (WNV) and Usutu virus (USUV) are neurotropic Orthoflaviviruses sharing a similar enzootic transmission cycle primarily involving Culex pipiens mosquitoes as vectors and birds as amplifying hosts. First identified in Africa, both viruses established endemicity across Europe over the past two decades, most likely introduced and spread by migratory bird species along Mediterranean flyways. In avian species, infection outcomes range from subclinical to fatal neuroinvasive disease, varying by viral strain, host immunity, and species susceptibility. Southern France emerges as a key hotspot for the circulation of these viruses, supported by diverse avian habitats conducive to year-round viral maintenance. This study investigated the prevalence of WNV and USUV in more than 2500 sedentary and migratory wild birds from these regions during 2024-2025 using molecular surveillance. Samples were collected using mist net and bird boxes, across multiple passerine and non-passerine taxa, spanning wetlands, urban fringes, and agricultural zones. Our analyses revealed widespread viral circulation across diverse species, mainly among passerines such as great tits, house sparrows, and barn swallows with USUV detected at higher rates than WNV in both study years. Overall prevalence was markedly higher in 2024 than in 2025, potentially reflecting climatic or ecological drivers. Migratory individuals likely seed viral introductions during seasonal passages, whereas resident populations sustain local enzootic cycles, facilitating overwintering persistence. These results highlight the pivotal role of mixed avifauna in arbovirus dynamics within Mediterranean Europe and emphasize the necessity for integrated, year-round surveillance targeting high-risk species and habitats. Enhanced monitoring will aid in predicting spillover risks and informing vector control strategies to mitigate zoonotic threats.

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Frequent introductions and climate suitability drive increasing dengue risk in Florida

Taylor-Salmon, E.; Chew, Y. T.; Lopes, R.; Locksmith, T.; Kopp, E.; Vergara, J.; Davis, A.; Mitchell, M.; Colarusso, P.; Schmedes, S.; Mock, V.; Scott, B.; Zimler, R.; Vasquez, C.; Moreno, M.; Paul, L. M.; Michael, S. F.; Breban, M. I.; Vogels, C. B. F.; Warren, J. L.; Carlson, C. J.; Stanek, D.; Heberlein, L.; Hill, V.; Morrison, A.; Grubaugh, N. D.

2026-05-04 epidemiology 10.64898/2026.05.01.26352185 medRxiv
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In recent years, detection of local dengue cases in Florida have increased in both frequency and geographical extent. From 2022 to 2024, consecutive outbreaks in Miami-Dade County were mainly caused by a single lineage of dengue virus (DENV) serotype 3, prompting questions about changing epidemiology and a transition towards endemicity. In this study, we used mathematical modeling and genomic epidemiology to reveal the spatiotemporal dynamics and drivers of local dengue cases in Florida. We found that annual clusters and outbreaks were caused by frequent short-lived DENV introductions, primarily from the Caribbean, and did not find evidence for local trans-seasonal DENV lineage persistence. Further, we show that the climate-driven increases in local suitability for Aedes aegypti transmission and travel-associated cases were the greatest risk factors for outbreaks in Miami-Dade and the geographic expansion of dengue in Florida. Overall, while we do not yet find evidence for endemicity, we demonstrate how climatic trends are enhancing the local public health risk caused by dengue in Florida.

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Dengue spatiotemporal patterns in Minas Gerais, Brazil, 2014-2023: regional epidemic forces dominate over the environmental impact of the Brumadinho dam collapse

Fernandes, G. d. R.; Vaz, A. B. M.; Fonseca, P. L. C.; Oliveira, W. K.; Aguiar, E. R. G. R.; Lopes, B. C.; Mota-Filho, C. R.; Castro, M. L. P.; Starling, C. E.

2026-05-26 epidemiology 10.64898/2026.05.19.26353615 medRxiv
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Background: Dengue is a major public health problem in Brazil, and Minas Gerais is one of the states with the highest burden. In January 2019, the Brumadinho dam collapse released about 12 million cubic meters of iron ore tailings into the Paraopeba River basin, causing environmental disturbance that could plausibly affect vector habitats and dengue transmission. We evaluated the spatiotemporal dynamics of dengue in Minas Gerais from 2014 to 2023 and tested whether the disaster was associated with changes in affected municipalities. Methods: We performed an ecological spatiotemporal analysis using dengue notifications from SINAN for all municipalities in Minas Gerais (2014-2023). Municipalities were classified as Paraopeba basin, regional controls, or state controls. Temporal similarity was assessed using Pearson correlation-based hierarchical clustering and non-metric multidimensional scaling (NMDS). Sources of variation were examined with PERMANOVA and principal component analysis (PCA). A linear mixed-effects model with municipality as a random effect was used to test changes after 2019, with pre/post contrasts estimated from marginal means. Results: Dengue showed strong temporal synchrony across the state, with major epidemic peaks in 2015-2016, 2019, and 2023. Health region explained 31.5% of the variation in temporal incidence profiles (p = 0.001), whereas Paraopeba basin status explained no significant variation (p = 0.998). No temporal cluster was enriched for municipalities in the Paraopeba basin. PCA identified 2023, 2019, and 2016 as the main years driving variability. In the mixed model, year was significant (p < 0.001), but Paraopeba basin status and its interaction with time were not. Incidence increased significantly after 2019 in non-exposed municipalities (p < 0.001), but not in basin municipalities (p = 0.088). Conclusions: Dengue dynamics in Minas Gerais were driven mainly by regional and state-wide epidemic processes, with no significant independent effect of the Brumadinho dam collapse on notified dengue patterns.

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Transcriptomic profiling of embryo-derived cell lines from the Chagas disease insect vector Rhodnius prolixus

de Andrade Tavares, L.; Garcia, A. C.; Bell-Sakyi, L.; Fontenele de Brito, T.; Pane, A.

2026-05-12 genetics 10.64898/2026.05.08.723764 medRxiv
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Rhodnius prolixus is a primary insect vector of Trypanosoma cruzi, the causative agent of Chagas disease, a neglected parasitosis endemic in Latin American countries. It has been estimated that Chagas disease affects 7-8 million people worldwide and is responsible for approximately 1000 deaths per year. Genetic and molecular studies in this species remain challenging due to its life cycle and feeding habits, thus hindering the development of new strategies to control their populations and reduce the diffusion of Chagas disease. Recently, two stable cell lines - RPE/LULS53 and RPE/LULS57 - were derived from Rhodnius embryos, which represent promising new tools to investigate the genetics of this insect vector. Here, we describe their gene expression landscapes through transcriptomic approaches. We show that 8,968 expressed genes are shared between the two cell lines, whereas 391 and 1,088 genes are uniquely expressed in RPE/LULS53 and RPE/LULS57, respectively. Although key components of primary developmental, immune and redox signaling pathways are expressed in both cell lines, some genes such as Frizzled-10-a-like and catalase show marked differences in expression. Our results strongly suggest that RPE/LULS53 and RPE/LULS57 likely represent two different cell phenotypes. Consistent with this, gene ontology analysis reveals that RPE/LULS53 is enriched for animal organ morphogenesis and stress response, while RPE/LULS57 for DNA-directed RNA polymerase activity, among others. Despite these differences, both cell lines express comparable levels of transcripts from resident transposable elements, including the highly abundant Mariner and LINE/I elements, as well as horizontally transferred transposons. Our findings shed light on the nature of the RPE/LULS53 and RPE/LULS57 embryo-derived cell lines and provide valuable transcriptomic resources for future genetic and functional studies in Rhodnius and other triatomine insect vectors. Author summaryRhodnius prolixus is a blood-feeding insect and a major vector of Chagas disease, a parasitosis endemic in Latin America and affecting millions of people worldwide. In the absence of effective drugs and vaccines, the control of the insect population represents a promising strategy to reduce the diffusion of the disease. Yet, genetic and functional studies in Rhodnius are extremely challenging due to its feeding habit and life cycle. To overcome these limitations, researchers have previously developed two stable cell lines derived from Rhodnius embryos. In this study, we provide the first characterization of the genes expressed in these cell lines. We found that, while the two cell lines share many expressed genes, each of them also has distinct gene expression patterns pointing to two different cell types with specialized functions. These differences likely affect the way they respond to stress and regulate biological processes. Our findings provide an important resource for researchers studying Rhodnius prolixus and other insect vectors, helping advance our understanding of the genetic and molecular mechanisms that control the insect development and mediate the interactions between insect vectors and the parasites they transmit

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Characterisation of novel bacteriophages against the cattle pathogen Moraxella bovis

Sampson, H. R.; Wegrzyn, M.; Josephs, T.; Ugokwe, N. I.; Kinsella, A.; Thanki, A. M.; Kalra, D. K.; Roux, A.; Patrick, H. L.; Swift, B. M.; Firth, G.; Odedra, R.; Millard, A. D.; Clokie, M. R.

2026-05-04 microbiology 10.1101/2025.11.24.690234 medRxiv
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BackgroundInfectious bovine keratoconjunctivitis is the most important cattle ocular disease worldwide. The infection is primarily caused by Moraxella bovis and is a highly contagious disease that significantly affects cattle welfare. Currently, antibiotic medication is the primary treatment for infectious bovine keratoconjunctivitis. However, with rising concerns over antibiotic resistance, we propose developing a more targeted therapeutic strategy using bacteriophages (phages). Materials and MethodsWe have isolated the first known Moraxella bovis phages, characterised them according to their genome sequence, local virulence index and with transmission electron microscopy. The host ranges were assessed using 41 clinical M. bovis strains isolated from infected cows. ResultsFour phages were isolated and characterised. Comparative analysis identified a high degree of genomic similarity between the phages MB15, MB16, MB26 and MB43. MB43 was the most distinct, with the smallest host range phenotype. ConclusionsThe isolated phages show therapeutic potential for further development against Moraxella infections.

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Ambient temperature storage of individual parasitic nematode larvae for whole-genome sequencing.

Viney, M.

2026-05-20 genomics 10.64898/2026.05.15.724465 medRxiv
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Soil-transmitted helminth (STH) infections are a major public health burden, and there are programmes of mass drug administration that attempt to ameliorate the harm that they cause. There has been increasing use of genomics to study STH infections and other parasitic nematodes, with particular interest in whole genome sequencing (WGS). For such studies, samples are commonly stored frozen, but in settings where these infections are endemic this can be difficult, and so there would be advantages to having ambient temperature storage methods. We investigated two ambient temperature storage methods - FTA cards and DESS buffer - for infective larvae of the rat parasites Nippostrongylus brasiliensis and Strongyloides ratti, prior to DNA extraction and then WGS. Our results showed that for individual larvae stored on FTA cards or in DESS buffer, this resulted in a lower proportion of sequence reads that mapped to the reference genomes, compared to the frozen control samples. Generally, for individual larvae, DESS-storage resulted in better sequencing results than FTA-storage. However, for pools of 10 or 50 larvae, then these ambient temperature storage methods generally resulted in comparable sequence read mapping to the frozen control samples.

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Canine Rabies in NDjamena: A Metapopulation SEIR Model Incorporating Vaccination and Inter-Patch Distances

Djimramadji, H.; Koutou, O.; Dawe, S.

2026-05-12 epidemiology 10.64898/2026.05.08.26352733 medRxiv
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Canine rabies persists in NDjamena (Chad) despite vaccination campaigns exceeding 70% coverage, suggesting a role for dog mobility and spatial heterogeneity. We propose a metapopulation SEIR model incorporating distance-modulated dog movements and an explicit vaccinated class. Analysis of the isolated patch establishes global stability of the disease-free equilibrium via a Lyapunov function. For the metapopulation, a composite Lyapunov function shows that elimination is governed by a reproduction number [R]v. Calibrated with field data (2012-2022), simulations reveal that uniform vaccination of both patches reduces [R]v by 46% (from 2.84 to 1.52) but does not achieve elimination, while targeted strategies are less effective. These results demonstrate that exhaustive vaccination coverage across the entire urban network and increased vaccination intensity are necessary to eliminate canine rabies in NDjamena. Our model provides a quantitative framework for planning effective control strategies.

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Systems-level analysis of RDK1 reveals compartment-specific kinase activity and a function in the maintenance of the mitochondrial proteome in Trypanosoma brucei

DUBEY, A.; Pandey, P.; Bui, D. S. H.; Aleke, C. O.; Smith, J.

2026-05-07 microbiology 10.64898/2026.05.05.722970 medRxiv
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Repressor-of-differentiation kinase 1 (RDK1) is one of two kinases expressed in bloodstream form Trypanosoma brucei parasites that were found to repress premature and spontaneous differentiation into the insect procyclic form. However, the effect of RDK1 RNAi was previously limited to the expression of a single surface coat protein, EP1 procyclin. Thus, there remains a significant gap in knowledge on the impact of RDK1 expression in bloodstream form T. brucei parasites. Here, we employ a systems biology approach and performed several proteomics analyses to identify RDK1 protein interactions and to determine the impact of loss of RDK1 expression on the bloodstream form proteome and phosphoproteome to uncover clues about potential mechanisms for RDK1 function. We found that RDK1 is dual localized to the cell membrane and the mitochondrial inner membrane with the kinase domain oriented towards the cytoplasm and mitochondrial inner membrane. Unexpectedly, the most enriched RDK1-proximal proteins were mitochondrial proteins. Furthermore, RDK1 depletion causes bloodstream form parasites to significantly upregulate many mitochondrial proteins and glycosomal proteins, several of which are upregulated in procyclic form parasites. Surprisingly, the mitochondrial phosphoproteome is largely unaffected by RDK1 depletion, while RDK1-dependent phosphoregulation is restricted to the cell membrane localization of RDK1. Lastly, we determined that RDK1 does not possess adenyl cyclase activity or alter intracellular cAMP levels; however, the dysregulated phosphoproteins correlate with functions in cyclic nucleotide signaling. In conclusion, RDK1 exhibits localization-specific kinase activity to regulate cyclic nucleotide signaling and mitochondrial proteomic maintenance in bloodstream form parasites. IMPORTANCETrypanosoma brucei is the unicellular parasite that causes African sleeping sickness and nagana disease in livestock across 36 sub-Saharan African countries. The parasite encounters different environmental niches as it is transmitted from an infected human to the tsetse fly vector as the fly takes a blood meal. T. brucei must sense environmental cues to initiate intracellular signaling pathways to promote effective differentiation and cellular remodeling from the mammalian bloodstream forms to the insect procyclic form. RDK1 is one of two kinases shown to repress premature differentiation to procyclic form, which would be detrimental for parasite survival in the human host. Therefore, it is essential to uncover mechanisms of RDK1 function to better understand how T. brucei maintains homeostasis in the human host and signals for effective cellular remodeling during parasite transmission.

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Biting Diptera-host network structure varies with anthropogenic landscape modification

Bellekom, B.; Hemprich-Bennett, D. R.; Acquaah, N. A.; Adams, B. A. R.; Donkor, E.; Aboagye-Antwi, F.; Lewis, O.; Hackett, T. D.

2026-05-06 public and global health 10.64898/2026.05.05.26352205 medRxiv
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O_LIRapid and ongoing anthropogenic habitat modification has the potential to alter the species composition, abundance and activity of biting insect communities, which are important disease vectors. The resulting changes in the network of interactions between biting insects and their hosts have implications for the transmission of vector-borne pathogens. C_LIO_LIWe used DNA metabarcoding of Diptera blood meals to document bipartite networks of interactions between biting flies (Diptera) and their hosts (including humans, domesticated and wild animals) across a gradient of anthropogenic habitat modification (village, agricultural and near-natural habitat) surrounding two rural villages in Ghana. C_LIO_LIWe collected 7,095 biting Diptera (of 42 species) from 30 collection sites, and generated sequencing data from 75 blood meals (from 29 species). These blood meals contained DNA from 18 vertebrate host species, dominated by humans and their livestock. C_LIO_LIHabitats with lower levels of anthropogenic modification had higher richness of biting Diptera and their host species. Species diversity and evenness did not differ significantly among habitats. Less modified habitats had higher network specificity, but connectance was highest in heavily modified habitats. C_LIO_LIHumans were highly embedded within biting Diptera-host networks, detected in 68% of blood meals. The networks reveal several potential disease transmission pathways linking competent vectors with susceptible hosts. The presence of mixed blood meals containing DNA of both human and wild animal origin highlights the potential for transmission of established and emerging zoonotic disease via bridge vectors. The high betweenness-centrality within interaction networks of the important disease vector Culex watti, combined with its high abundance across all levels of anthropogenic landscape modification, suggest that it may be a connector species, linking and facilitating disease transmission between spatially distinct communities. C_LIO_LISynthesis and applications: Our results are of epidemiological interest, as they identify the exposure of humans to pathogen transmission cycles across a gradient of anthropogenic habitat modification through the movement of opportunistic bridge vectors. We discuss the implications for the transmission of emerging and established zoonotic disease and for the targeting and implementation of initiatives to reduce disease exposure and transmission. C_LI

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An improved generic schema for high fidelity data linkage and sample tracing across complex multi-assay medical entomology studies

Kavishe, D. R.; Msoffe, R. V.; Mmbaga, S.; Tarimo, L. J.; Butler, F.; Kaindoa, E. W.; Govella, N. J.; Kiware, S. S.; Killeen, G.

2026-05-13 bioinformatics 10.64898/2026.05.11.724183 medRxiv
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Evidence-based decision making on malaria vector control strategies increasingly rely on triangulation of data which requires informatics systems that can integrate data from complex, multi-stage studies involving mosquitoes. This manuscript describes a performance evaluation of an extended version of the generic schema underpinning the VBDs360 platform, specifically improved to accommodate multiple distinct entomological assays spanning the field, insectary and laboratory. The utility of this extension, with respect to high-fidelity data linkage and robust sample traceability across complex entomological workflows, was evaluated through a case study conducted in southern Tanzania. Wild female mosquitoes were collected from 40 locations across a >4,000 km{superscript 2} area and then reared through multiple generations in an insectary before derived iso-female lineages were tested for phenotypic susceptibility to a pyrethroid insecticide. Such multi-generational lineages (F to F where n [&ge;] 2) were propagated to prevent non-heritable maternal effects on phenotype and produce enough progeny for standard WHO susceptibility assays. All samples were subsequently archived in a molecular laboratory, where all F specimens were tested for sibling species identity. A paper-based implementation of the extended schema enabled successful integration of 77,017 lines of data distributed across 6 different tables that spanned 3 distinct field, insectary, and laboratory workflows, implemented by three different teams working in different locations. At each step, fully independent and redundant primary and secondary keys enabled high fidelity error correction and sample tracing. Consistently perfect linkage between assay design and sample sorting data was achieved for F0 wild-caught adults, with 100% of 66,108 record successfully linked between field capture and morphological categorization. This complete traceability extended to the propagation of derived Fn lineages, with all 100 and 243 records from 9 adult-derived and 13 larval-derived lineages, respectively, correctly linked. Insecticide susceptibility phenotype further confirmed 100% linkage for 5,654 records between exposure history and recorded mortality outcome data in the insectary. Although such cross-cleaned linkages to sample analysis and storage data recorded by the laboratory team were not entirely perfect and could be improved, they were nevertheless of very high fidelity (97.3% (1967/2,022) for F0 samples and 99.3% (437/440) for Fn samples). Overall, this pilot application of the extended generic schema ensured robust data provenance and minimized transcription errors in this complex study distributed across multiple teams and locations. These findings demonstrate how this generic informatics framework may be scaled and adapted to support data integrity across diverse, large-scale, multi-team entomological research workflows.

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How urban vegetation influences dynamics of Aedes albopictus egg density: three years of surveillance in Montpellier (France)

Bartholomee, C.; Sutter, C.; Fournet, F.; Bouhsira, E.; Moiroux, N.

2026-05-16 ecology 10.64898/2026.05.15.725325 medRxiv
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Nature-Based Solutions are increasingly promoted to address current urban challenges. While their potential effects on vector-borne disease risks have been documented, data on Aedes albopictus, a known arbovirus vector, remain limited in France. A previous study showed that urban vegetation moderately increases the abundance of adult mosquitoes of this species, but the monitoring period lasted only six months. Using ovitraps, we monitored Ae. albopictus egg density dynamics over multiple years (2022 to 2024) and analysed its environmental predictors in various urban environments. We included lagged meteorological variables, land cover metrics, and the cumulated egg densities recorded in the previous weeks as environmental predictors. Both parametric (GLMM) and non-parametric (Random Forest) models were fitted to weekly egg counts per trap. Our findings highlight that (i) egg density dynamics were related to how vegetation classes structured the landscape, (ii) growing degree days and cumulated number of eggs recorded in specific lagged time windows were the main contributors to egg density, and (iii) the non-parametric and parametric models performed similarly in terms of prediction accuracy.

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A trait-based framework for quantifying arthropod invasion potential: Predictive modeling with Tropilaelaps mites as a case study

Black, C.; Thompson, T.; Sankovitz, M.; Ramsey, S. D.

2026-05-08 ecology 10.64898/2026.05.06.723306 medRxiv
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Over the past decade, the global rise in invasive species has accelerated at an unprecedented rate, intensifying threats to ecosystems, human health, and economies worldwide. Newly invasive taxa, such as Tropilaelaps mites, are of particular concern for apiculture and agroecosystems. Despite growing concern about the spread of Tropilaelaps mites and other arthropods, limited resources are available to assess their invasive potential. We characterized 118 invasive arthropod species using available literature to identify key biological and ecological traits associated with invasive potential. We developed predictive generalized linear mixed models (GLMMs) to determine the traits most important for predicting invasive potential (number of invaded regions), and the top-performing models were subsequently applied to Tropilaelaps mercedesae. Several traits were identified as significant predictors of invasiveness, including the degree of human association, resilience at small population sizes, diet breadth, maximum annual number of generations, altitude range, and the interaction between human association and temperature range. Notably, T. mercedesae was predicted to be capable of invading 160 regions, ranking it within the top 10% most invasive species among those evaluated (12th out of 119), ranked just below the cosmopolitan Varroa destructor mite. These findings position T. mercedesae as a high-risk, yet under-recognized, invasive threat. Collectively, this demonstrates the power of predictive trait-based modeling to inform invasion risk prior to widespread establishment and underscores the urgency of reallocating resources toward surveillance, research, and proactive management strategies rather than relying on costly, often ineffective post-establishment eradication.

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Genetic diversity of tomato brown rugose fruit virus in Morocco

Maachi, A.; Donaire, L.; Aranda, M. A.

2026-05-12 microbiology 10.64898/2026.05.11.724243 medRxiv
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Tomato brown rugose fruit virus (Tobamovirus fructirugosum) is an emerging virus that affects tomatoes, capsicum, and chili. Since its first detection in Jordan in 2015, the virus was reported in more than 40 countries across all the continents. In Morocco, the virus was reported for the first time in October 2021. However, its genetic diversity remains unexplored. In this work, we used a collection of tomato fruits from local markets to investigate the variability of the virus in the country. We explored the different pressures acting on the N-terminus of the RNA-dependent RNA polymerase, the movement protein, and the coat protein genes. Then, we used haplotype network analyses to reveal the population structure within the Moroccan isolates and studied their relationships with the ones from the world. We found that genetic diversity is low, which is consistent with the global situation. No signatures of diversifying selection were detected across the analyzed genes. However, the virus sequences from Morocco showed a clear geographic structure, suggesting that geographic factors probably combined with agricultural practices may contribute to shaping the population structure of ToBRFV in Morocco.