Parasit Vectors [JOURNAL]
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200 papers
Relative proportion and contrasting host preference of Culex pipiens biotypes across Europe.
Menon R, Andreadis SS, Koenraadt CJM … +3 more , Verhulst NO, Ignell R, Hill SR
Parasit Vectors · 2026 Apr · PMID 41923113 · Full text
BACKGROUND: The primary vector of West Nile virus (WNV) in Europe, Culex pipiens, has two morphologically identical but behaviorally and genetically distinct biotypes, here referred to as Pipiens and Molestus. Pipiens an...
BACKGROUND: The primary vector of West Nile virus (WNV) in Europe, Culex pipiens, has two morphologically identical but behaviorally and genetically distinct biotypes, here referred to as Pipiens and Molestus. Pipiens and Molestus, and their hybrids, are differentially distributed across Europe and display variable patterns of blood-feeding on birds and humans across the continent, but whether host choice correlates with host preference is unclear. METHODS: Samples of mosquitoes were collected and subsequently biotyped using real-time PCR, following which the relative proportions of each biotype and the hybrids was recorded and their host preference analyzed using a two-choice trapping assay. Each trapping assay consisted of two BG-Sentinel type 2 traps, which were baited with CO and either a synthetic human odor blend or a chicken odor blend. The trapping assays were conducted in peri-urban sites in the Netherlands, Switzerland and Greece. RESULTS: The relative proportions of Molestus and hybrids were higher in Greece than in the northern locations, while Pipiens remained the dominant biotype across all trapping locations. In Greece, the host preference of Pipiens and Molestus was for avian and human odors, respectively, whereas the host preference was reversed in the Netherlands and Switzerland. The hybrids were opportunistic in host preference regardless of trapping location. CONCLUSIONS: The relative proportions of Pipiens and Molestus and their hybrids vary across Europe. The observed variance in host preference, ranging from opportunistic to weakly ornithophilic for Pipiens, from ornithophilic to mildly anthropophillic for Molestus and opportunistic for hybrids-depending on latitude-may have an impact on WNV transmission. This study highlights the discrepancy between host choice and host preference, and the efficacy of the synthetic host odor blends for surveilling the relative proportion and host preference of Cx. pipiens. This methodology provides a framework and the tools required for a more accurate assessment of vectorial capacity and prediction of WNV outbreaks, and may be used to understand the genetic mechanisms regulating host preference.
Presence of localized elevated metabolic enzymes and kdr mutations in the voltage-gated sodium channel gene indicate early evidence of resistance of Phlebotomus argentipes to alpha-cypermethrin in Bihar, India.
Shukla A, Chaubey R, Kushwaha AK … +7 more , Rai UG, Kumar R, Petersen C, Lawyer P, Rowton E, Bernhardt SA, Sundar S
Parasit Vectors · 2026 Mar · PMID 41918020 · Full text
BACKGROUND: Visceral leishmaniasis, caused by Leishmania donovani and transmitted by Phlebotomus argentipes, remains a major public health challenge in the Indian subcontinent. Sand fly populations are controlled by usin...
BACKGROUND: Visceral leishmaniasis, caused by Leishmania donovani and transmitted by Phlebotomus argentipes, remains a major public health challenge in the Indian subcontinent. Sand fly populations are controlled by using different insecticides, particularly dichlorodiphenyltrichloroethane (DDT) and pyrethroids such as alpha-cypermethrin. Prolonged and irregular use of these insecticides raises concern about the development of resistance in sand fly populations. METHODS: This study aimed to compare metabolic detoxification and knockdown resistance (kdr) mutations in Vgsc and ace-1 between nine sprayed (indoor residual spray, IRS) villages and one unsprayed (non-IRS) village in Muzaffarpur, Bihar, India. A total of 10 Ph. argentipes from each village were used for metabolic detoxification and 10-25 Ph. argentipes were used for target site insensitivity mutations. Homogenized Ph. argentipes aliquots were used for different enzymes activity and DNA was used for the sequence analysis of Vgsc and ace-1 genes to access the presence of kdr mutations. RESULTS: Biochemical assays revealed that levels of detoxification enzymes, including glutathione S-transferase (GST), esterase (PNPA), and cytochrome P450 monooxygenase, were elevated in IRS villages, suggesting localized metabolic resistance. Molecular screening of the voltage-gated sodium channel (Vgsc) gene revealed high frequencies of knockdown resistance (kdr) mutations at codon 1014, with serine (L1014S) (48.5%) being the most prevalent, followed by wild type leucine (L1014) (39.5%). No mutations were detected at codon 119 of the ace-1 gene, indicating the sensitivity to organophosphates in the sand fly population. CONCLUSIONS: The results suggested that continuous and repeated exposure to the synthetic pyrethroid may exert selective pressure, leading to early signs of resistance in Ph. argentipes, mediated through metabolic detoxification mechanisms and mutation in the kdr gene. These findings underscore the importance of ongoing resistance monitoring and the implementation of rotational insecticide strategies to support sustained efforts toward the elimination of visceral leishmaniasis.
Long-term ecological surveillance of hard ticks (Acari: Ixodidae) and SFTSV in Dangjin, South Korea (2018-2024).
Shin HJ, Jeong JY, Hong CE … +8 more , Lee H, Lee KW, Lee WG, Park JE, Song DK, Moon CI, Hwang HJ, Lee YS
Parasit Vectors · 2026 Mar · PMID 41913303 · Full text
BACKGROUND: Hard ticks (Ixodidae) are the primary vectors of severe fever with thrombocytopenia syndrome virus (SFTSV), a tick-borne pathogen of increasing public health concern in East Asia. Understanding local vector e...
BACKGROUND: Hard ticks (Ixodidae) are the primary vectors of severe fever with thrombocytopenia syndrome virus (SFTSV), a tick-borne pathogen of increasing public health concern in East Asia. Understanding local vector ecology requires long-term monitoring, particularly in regions where human cases occur but viral prevalence in questing ticks remains unclear. This study conducted multi-year ecological and molecular surveillance of hard ticks and SFTSV in Dangjin-si (City), Chungcheongnam-do (Province), a representative region in west-central ROK. METHODS: From 2018 to 2024, ticks were collected monthly from April to November across four habitat types (grassland, mountain road, mixed forest, and cemetery) using standardized 24-h CO-baited traps. Specimens were morphologically identified, and a stratified subset was selected for molecular screening after stratification by habitat, species, developmental stage, and sex (for adults). Pooled samples were constructed within each stratum, with up to 50 larvae, 30 nymphs, or 5 sex-separated adults per pool. In total, 36,478 ticks were assembled into 3106 pools and screened for SFTSV by nested reverse transcription (RT)-PCR. Amplification products were evaluated by agarose gel electrophoresis. RESULTS: Across the surveillance period, 72,956 ticks (adults, nymphs, and larvae) were collected. Among the collected ticks, three species were identified: Haemaphysalis longicornis (46,269), H. flava (1,143), and Ixodes nipponensis (655). H. longicornis was the most frequently collected and accounted for 63.42% of all adult and nymphal ticks. Tick abundance peaked during 2018-2019 and was highest in grassland habitats. SFTSV was not detected in any of the 3106 pools. CONCLUSIONS: Although SFTSV was not detected in the screened stratified subset, the persistently high abundance and broad ecological distribution of Haemaphysalis species indicate that Dangjin-si (City) maintains environmental conditions that may support pathogen introduction or amplification. These long-term data provide an ecological baseline for early warning and support targeted surveillance in nearby areas with higher incidence. Integrating ecological, climatic, and epidemiological data, together with multi-pathogen molecular screening, will strengthen One Health-based risk assessment in low-prevalence settings.
Correction: Kdr genotyping and the first report of V410L and V1016I kdr mutations in voltage-gated sodium channel gene in Aedes aegypti (Diptera: Culicidae) from Iran.
Enayati A, Valadan R, Bagherzadeh M … +14 more , Cheraghpour M, Nikookar SH, Fazeli-Dinan M, Hosseini-Vasoukolaei N, Rostami FS, Kordshouli RS, Raeisi A, Nikpour F, Mirolyaei A, Bagheri F, Sedaghat MM, Zaim M, Weetman D, Hemigway J
Parasit Vectors · 2026 Mar · PMID 41913287 · Full text
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Environmental drivers of tick density in UK dairy farms: implications for livestock health and agri-environment policy.
Shanks S, Duncan J, Johnson N … +5 more , Goswell J, Hartley C, Hassall R, Purse BV, Millins C
Parasit Vectors · 2026 Mar · PMID 41913260 · Full text
BACKGROUND: Ticks are important vectors of livestock and human pathogens in Europe. Environmental policies promoting woodland creation and habitat restoration are increasing habitat suitability for Ixodes ricinus but imp...
BACKGROUND: Ticks are important vectors of livestock and human pathogens in Europe. Environmental policies promoting woodland creation and habitat restoration are increasing habitat suitability for Ixodes ricinus but impacts on livestock tick-borne disease risk remain unclear. This study examined how landscape features influence tick distribution on UK dairy farms with a recent history of tick-borne disease. METHODS: Questing ticks were sampled on 72 pastures in 12 dairy farms in southwest England (2376 transects), stratified by distance from pasture boundaries and adjacency to woodland or non-woodland habitats. Environmental variables were measured at transect, boundary, and pasture scales. Generalized linear mixed models identified predictors of tick presence in pastures, and nymph density at pasture boundaries. Farm-level associations between tick abundance, woodland cover, and cattle pathogen prevalence were assessed descriptively. RESULTS: A total of 1701 ticks were collected (91.3% nymphs). Ticks were detected on 20% of transects and in 89% of pastures, with densities strongly aggregated at pasture boundaries. The proportion of woodland cover within 50 m buffers was the dominant environmental driver at both boundary and pasture scales, with greater cover associated with higher nymph densities and increased probability of tick presence. Boundaries adjacent to water also supported significantly higher nymph densities. CONCLUSIONS: Local landscape features, particularly woodland cover and small water bodies at boundaries, strongly influence tick distribution in UK dairy pastures. Woodland expansion through environmental schemes may therefore be associated with increased tick distribution and densities in farmed landscapes, with implications for livestock exposure and public health.
First record of Phlebotomus (Larroussius) orientalis (Parrot, 1936) (Diptera: Psychodidae) in Israel: phylogeographic placement and implications for leishmaniasis surveillance.
Diaz D, Kniha E, Koblmüller S … +11 more , Studentsky L, Elbaz SL, Ben Avi I, Shilo S, Kalmus S, Akad F, Naveh I, Reicher S, Davidovich-Cohen M, Orshan L, Kirstein OD
Parasit Vectors · 2026 Mar · PMID 41906122 · Full text
BACKGROUND: Phlebotomine sand flies (Diptera: Psychodidae) are the principal vectors of Leishmania spp., the causative agents of leishmaniasis. Since 2008, the Ministry of Health and the Ministry of Environmental Protect...
BACKGROUND: Phlebotomine sand flies (Diptera: Psychodidae) are the principal vectors of Leishmania spp., the causative agents of leishmaniasis. Since 2008, the Ministry of Health and the Ministry of Environmental Protection of Israel have conducted nationwide, periodic sand fly surveys. Initially, these surveys focused on localities with known endemic transmission of cutaneous leishmaniasis, but in recent years, entomological trapping has expanded to areas where prior information on sand flies was unavailable. Here we report the first confirmed occurrence of Phlebotomus (Larroussius) orientalis (Parrot, 1936) in Israel and place the Israeli material in a comparative phylogeographic context. METHODS: Entomological surveys by CO trapping were conducted in the Negev Desert, southern Israel, between 2020 and 2024. Morphological sand fly identification was confirmed by sequencing fragments of the mitochondrial COI and Cytb/NADH1 genes. For a newly reported species, we inferred intraspecific phylogenetic relationships and divergence times between major clades. A subset of females was additionally screened for Leishmania DNA and vertebrate blood-meal sources by real-time polymerase chain reaction (PCR) coupled with high-resolution melt analysis. RESULTS: Targeted surveys and routine surveillance in the Negev region between 2020 and 2024 yielded 269 Phlebotomus orientalis (96 males, 173 females) among other species of local sand fly fauna from multiple wadi systems in the central Negev. These detections constitute the first confirmed records of Ph. orientalis in Israel. Species identification was confirmed through both morphological examination and molecular analyses of partial COI and Cytb/NADH1 genes. Phylogenetic analysis indicated that the Israeli Ph. orientalis specimens constitute a distinct lineage that diverged from East African conspecifics during the Early to Middle Pleistocene. Blood-meal analysis of engorged Ph. orientalis females identified the European hare as a vertebrate host, and none of the tested Ph. orientalis specimens were positive for Leishmania DNA. CONCLUSIONS: Phlebotomus orientalis is a confirmed vector of L. donovani, the main agent of visceral leishmaniasis in East Africa. Its detection as a distinct and apparently long-established lineage in the Negev, in a region where parasites of the L. donovani complex are already involved in cutaneous leishmaniasis transmission, highlights the need to clarify the distribution, ecology, and host preferences of Ph. orientalis in Israel. Further studies are required to characterize its spatial and seasonal occurrence, evaluate its vector competence for L. donovani and L. infantum, and assess its potential contribution to current and future leishmaniasis transmission risks.
Molecular screening of tick-borne pathogens in host-seeking Haemaphysalis punctata Canestrini & Fanzago, 1878 (Ixodoidea: Ixodidae) in Anatolia with the first report of Burana virus.
Orkun Ö, Özdemir T, Gündoğdu MN … +3 more , Yiğit M, Deniz A, Vatansever Z
Parasit Vectors · 2026 Mar · PMID 41897008 · Full text
BACKGROUND: Haemaphysalis punctata is a widespread Palearctic tick species, yet its role in the circulation of tick-borne pathogens in Türkiye remains poorly characterized. No systematic pathogen survey has previously be...
BACKGROUND: Haemaphysalis punctata is a widespread Palearctic tick species, yet its role in the circulation of tick-borne pathogens in Türkiye remains poorly characterized. No systematic pathogen survey has previously been conducted on host-seeking individuals of this species. This study aimed to provide the first comprehensive molecular investigation of bacterial, protozoan, and viral tick-borne pathogens (TBPs) in questing H. punctata populations in Central and Northeastern Anatolia. METHODS: A total of 96 host-seeking adult H. punctata were collected from 29 sampling sites in 11 districts across seven provinces. DNA and RNA extracts were screened using a multi-agent polymerase chain reaction (PCR)--sequencing panel targeting a broad range of TBPs. Positive amplicons were sequenced for species identification, and complete genome sequencing was performed for the detected Burana virus strain. Phylogenetic analyses were conducted using maximum-likelihood and Bayesian approaches. RESULTS: Microorganisms detected included Babesia major (5.21%), Theileria orientalis (1.04%), an uncharacterized Ehrlichia sp. (1.04%), and spotted fever group rickettsiae (3.13%) comprising Candidatus Rickettsia yenbekshikazakhensis and Rickettsia hoogstraalii. Coxiella burnetii was identified at the highest prevalence (20.83%), representing the first detection of this agent in questing H. punctata in Türkiye. Several ticks carried mixed infections. Notably, Burana virus was detected in one specimen-marking the first confirmed occurrence of this orthonairovirus outside Central Asia. Complete S, M, and L segment genomes were recovered, and phylogenetic analyses showed a close-though not identical-relationship to strains from Kyrgyzstan and Xinjiang. CONCLUSIONS: This study provides the first systematic assessment of TBPs in host-seeking H. punctata in Türkiye and documents, for the first time in this species, the presence of Burana virus, Candidatus R. yenbekshikazakhensis, T. orientalis, and C. burnetii. The findings highlight H. punctata as an underrecognized but epidemiologically relevant tick species in Anatolia and reveal previously undocumented microorganism circulation, with important implications for surveillance of emerging viral and zoonotic threats.
Evaluation of the safety and insecticidal efficacy of ivermectin-treated bird feed formulations in different avian species.
Savran MJ, Coffin K, Stewart CM … +14 more , Nguyen C, Puska C, Ring ME, Leon AS, Schweiner P, Peters T, Randall JC, Buczek J, Lado P, Gallichotte EN, Clapsaddle B, Barker CM, Ebel GD, Foy BD
Parasit Vectors · 2026 Mar · PMID 41896989 · Full text
BACKGROUND: West Nile virus (WNV) is maintained in an enzootic cycle between reservoir host birds and Culex (Cx.) spp. mosquitoes. This relationship presents a potential target for vector control strategies. Ivermectin (...
BACKGROUND: West Nile virus (WNV) is maintained in an enzootic cycle between reservoir host birds and Culex (Cx.) spp. mosquitoes. This relationship presents a potential target for vector control strategies. Ivermectin (IVM), an endectocidal drug that selectively affects invertebrates while remaining safe at high concentrations in mammals and birds, can be delivered to Culex tarsalis via blood meals from birds fed IVM-treated bird feed. In this study, we evaluated the safety, efficacy, and utility of IVM-treated bird feed as a novel vector control strategy by assessing its impact on multiple bird species and mosquitoes. METHODS: Mosquitoes were collected during peak WNV transmission season in Northern Colorado and DNA extracted from blood meals to determine host species. Chickens, pigeons, zebra finches, and house sparrows were fed different formulations of IVM-treated bird feed and observed for clinical signs, and their sera were fed to Cx. tarsalis mosquitoes to evaluate mosquitocidal efficacy. Feeding rates and IVM serum concentrations in birds were analyzed using unpaired t-tests and one-way ANOVA, and mosquito survivorship was analyzed using Kaplan-Meier curves and compared using paired log-rank tests. IVM serum concentration and mosquito survivorship were compared using Spearman correlation. RESULTS: Speciation analyses conducted on blood meals from Cx. tarsalis collected during peak WNV transmission season in Northern Colorado determined that they feed primarily on songbird species that commonly visit bird feeders, with house sparrows representing the most frequent blood meal host. In laboratory experiments using multiple formulations and doses of IVM, chickens, pigeons, zebra finches, and house sparrows ate comparable amounts of IVM-treated bird feed compared to untreated feed, had similar weight gain, and exhibited no clinical signs of toxicity. Both colony-reared and locally captured Cx. tarsalis showed significant mortality after feeding on sera from IVM-treated birds compared to controls. CONCLUSIONS: These results suggest that targeting songbirds with IVM-treated bird feed should be safe for wildlife and may elicit high rates of IVM-induced mortality by reaching a large proportion of WNV vector mosquitoes via their proclivity for feeding on passerine birds.
Bloodmeal analysis via COI-targeted DNA capture and enrichment identifies non-cattle hosts of Amblyomma variegatum on St. Croix, US Virgin Islands.
Ballard R, Williamson CHD, Kleinschmidt H … +8 more , Buckmeier G, Sahl JW, Olafson PU, Alfred JT, Busch JD, Wagner DM, Bonilla D, Stone NE
Parasit Vectors · 2026 Mar · PMID 41888950 · Full text
BACKGROUND: Amblyomma variegatum threatens the Caribbean cattle industry owing to its role as a vector for Ehrlichia ruminantium, the obligate intracellular bacterium that causes heartwater disease, an economically impor...
BACKGROUND: Amblyomma variegatum threatens the Caribbean cattle industry owing to its role as a vector for Ehrlichia ruminantium, the obligate intracellular bacterium that causes heartwater disease, an economically important and potentially fatal ruminant disease. Amblyomma variegatum is also a public health concern as a vector for Rickettsia africae, the causative agent of African tick-bite fever. Efforts to eradicate A. variegatum on Caribbean islands are ongoing to protect cattle from disease and prevent the spread of the vector and diseases to the American mainland. However, reinfestations often occur, possibly owing to the maintenance of ticks by non-cattle hosts that escape treatment. St. Croix in the US Virgin Islands has experienced such eradication challenges. METHODS: To determine whether persistence of A. variegatum populations on non-cattle hosts contributes to cattle reinfestation on St. Croix, we analyzed 1 non-attached A. variegatum adult female collected from a human and 14 questing adult females collected via cloth dragging along vegetation transects in Lower Love, St. Croix, during 2023. We conducted host bloodmeal analysis by obtaining vertebrate cytochrome c oxidase subunit I (COI) sequences from A. variegatum DNA extracts using COI-targeted DNA capture and enrichment to identify the most recent host bloodmeal. We also screened tick DNA extracts for E. ruminantium and Rickettsia DNA using pCS20 Sol1 and PanR8 qPCR, respectively. Rickettsia species identification was determined using ompA polymerase chain reaction (PCR) and Sanger sequencing, followed by phylogenetic analysis. RESULTS: We identified vertebrate COI sequences for the genera Capra and Canis in two A. variegatum ticks. Although E. ruminantium was not detected, DNA from R. africae was present in all 15 ticks. CONCLUSIONS: These results suggest that goats, and possibly canines, may serve as alternative hosts for A. variegatum on St. Croix, US Virgin Islands, which complicates eradication efforts focused entirely on the treatment of cattle. Fortunately, E. ruminantium was not identified in any ticks. However, R. africae was ubiquitous, which may be of concern for public health.
Differences in metaviromes between Aedes aegypti and Aedes albopictus from sympatric areas on Hainan Island and the Leizhou Peninsula, China.
Zhao M, Jiang Y, Ran X … +6 more , Liao Y, Zhang Q, Bai Y, Liu Q, Zhao T, Zhang H
Parasit Vectors · 2026 Mar · PMID 41888939 · Full text
BACKGROUND: Aedes aegypti and Ae. albopictus are the most important vector mosquito species globally and are capable of transmitting various viral diseases, such as dengue fever, zika virus disease, and chikungunya fever...
BACKGROUND: Aedes aegypti and Ae. albopictus are the most important vector mosquito species globally and are capable of transmitting various viral diseases, such as dengue fever, zika virus disease, and chikungunya fever. Although they overlap in terms of ecological niches and geographical distribution, their virus carriage and transmission capacities differ significantly. Metavirome studies can provide new perspectives for understanding these differences. METHODS: In this study, next-generation sequencing (NGS) was used to analyze the epidemiologically significant metaviromes of Ae. aegypti and Ae. albopictus on Hainan Island and the Leizhou Peninsula, China. A bioinformatics analysis pipeline was used to compare the viral compositions of the two mosquito species. RESULTS: In the sympatric areas, 250 viral species from 60 families were annotated to Ae. aegypti at the read level, whereas 406 vial species from 66 families were annotated to Ae. albopictus at the read level, revealing significant differences in the metaviromes of the two mosquito species. Notably, Ae. albopictus exhibited significantly greater viral diversity than Ae. aegypti (p < 0.05). The 50 viruses with the greatest abundance in two mosquito species were selected for data analysis, revealing 64% viral similarity, with 32 common viruses and 18 distinct viruses between the two species, although the relative abundances of each virus differed notably. Phasi Charoen-like Phasivirus (PCLV) from Phenuiviridae showed the highest relative abundance in all Ae. aegypti sample pools, whereas Orthophasmavirus barstukasense (Phasmaviridae), Gihfavirus pelohabitans (Steitzviridae), and unclassified Wenzhou sobemo-like virus 4 (WSLV4) predominated in different Ae. albopictus sample pools. CONCLUSIONS: The metavirome compositions of Ae. aegypti and Ae. albopictus in the sympatric areas of Hainan Island and the Leizhou Peninsula differed significantly. The viral diversity of Ae. albopictus was significantly higher than that of Ae. aegypti, and notable differences in viral composition and abundance were observed between the two species. However, the 50 most abundant viruses detected in both mosquito species also exhibited a degree of similarity. These findings support further research into the viral compositions of these two Aedes species. Moreover, analyzing these distinct viral compositions aids understanding of the vector capacity and vector competence of these mosquitoes, which will provide theoretical support for vector control efforts on Hainan Island and the Leizhou Peninsula.
Revisiting Leishmania (Viannia) lainsoni Silveira, Shaw, Braga, and Ishikawa, 1987: current knowledge and emerging perspectives.
de Morais TG, Campos MB, Silveira FT … +1 more , Vasconcelos Dos Santos T
Parasit Vectors · 2026 Mar · PMID 41882773 · Full text
More than three decades after its description, Leishmania (Viannia) lainsoni Silveira, Shaw, Braga, and Ishikawa, 1987 remains the least explored species of the subgenus Viannia Lainson and Shaw, 1987 within the genus Le...
More than three decades after its description, Leishmania (Viannia) lainsoni Silveira, Shaw, Braga, and Ishikawa, 1987 remains the least explored species of the subgenus Viannia Lainson and Shaw, 1987 within the genus Leishmania Ross, 1903. Although long considered rare and of limited clinical impact, recent records reveal a wider geographic range, diverse vector associations, and increasing involvement in American cutaneous leishmaniasis (ACL). Advances in molecular and genomic studies have clarified its taxonomy and uncovered notable biological and genetic variability. This review synthesizes current knowledge on the distribution, vectors, reservoirs, pathogenicity, and clinical relevance of L. (V.) lainsoni, highlighting emerging evidence that challenges earlier assumptions and emphasizing key research gaps for improving surveillance and understanding of its transmission dynamics.
Comprehensive validation of the rapid tick exposure test (RaTexT®): accuracy, reproducibility and comparative performance to detect acaricide resistance in livestock ticks.
Jongejan F, Berger L, Nagagi Y … +7 more , Muhanguzi D, van der Heide M, Wiggers B, Elders L, de Avelar BR, Ferreira PT, Klafke GM
Parasit Vectors · 2026 Mar · PMID 41877226 · Full text
BACKGROUND: RaTexT®, an innovative rapid tick exposure test, was recently developed to provide farmers with quick, on-site results to improve their acaricide resistance management. This was achieved by exposing partially...
BACKGROUND: RaTexT®, an innovative rapid tick exposure test, was recently developed to provide farmers with quick, on-site results to improve their acaricide resistance management. This was achieved by exposing partially engorged adult ticks to a specially designed acaricide-impregnated matrix fitted inside a transparent polypropylene box. Each RaTexT® box contains six strips of four small, interconnected compartments, in which ticks are exposed immediately after removal from cattle in the field. In this study, we assessed whether a single strip of four interconnected compartments, instead of six strips, was sufficient to accurately detect resistance to deltamethrin and to a combination of cypermethrin, chlorpyrifos and piperonyl butoxide (PBO). We also statistically analysed the optimal number of ticks per compartment (ranging between 5 and 8). Moreover, the test reproducibility was checked by two independent observers who counted dead and live ticks in each compartment. Finally, a comparative analysis was undertaken between adult ticks exposed in RaTexT® and in the adult immersion test (AIT), and also with larvae in the resistance intensity test (RIT) and in the larval packet test (LPT). The novelty of this study lies in comparing adult ticks exposed in RaTexT and in the AIT Test, thereby overcoming limitations of previous studies, in which adults in RaTexT were compared with larvae in the LPT. METHODS: The internal coefficient of variation (CV) was calculated for each dose, box and acaricidal product to assess within-box consistency. The effect of the number of ticks per compartment (n = 5-8) was examined using Monte Carlo simulations. Inter-observer reliability of reading RaTexT® was statistically measured using Cohen's kappa coefficient (κ). The comparative performance analysis of the bioassays was conducted using generalised linear models (GLMs) with laboratory and field strains of Rhipicephalus microplus ticks in Brazil. RESULTS: Overall agreement between individual strips and their corresponding box classification was 91.3%, indicating high consistency between replicates. The predefined threshold of ≥ 90% accuracy was met by a single strip, supporting the test's robustness even with minimal replication. The internal coefficient of variation within each RaTexT® box was high for deltamethrin (1.285 at 1× dose, 1.109 at 5× dose and 1.268 at 10× dose), but lower for cypermethrin/chlorpyriphos/PBO (0.648 at 1, 0.305 at 5× dose and 0.194 at 10× dose). Variability in the controls was relatively high (CV 1.776). Monte Carlo simulations showed that diagnostic accuracy gradually increased from 81.2% with five ticks to 86.1% with eight ticks per compartment. Furthermore, there was substantial agreement between the mortality of ticks assessed by two independent observers (κ = 0.664). Finally, the comparative test analysis revealed that the deltamethrin resistance level in RaTexT® matched that observed in the AIT. Resistance to deltamethrin was also confirmed by the LPT, with resistance ratios (RR) of 33.8 and 39.5 for two different field strains (Biotech and UFRRJ, respectively). For cypermethrin/chlorpyriphos/PBO, RaTexT® exhibited significantly lower mortality than the AIT. Resistance was also confirmed by LPT, with RR of 5.2 for Biotech strain and 7.2 for the UFRRJ strain. CONCLUSIONS: Overall, these findings demonstrate that RaTexT® is accurate and reproducible with a single test strip, making it a practical and cost-effective test that complements traditional laboratory bioassays.
Functional characterization of AsOBP21f, an odorant-binding protein involved in human odor detection in the malaria vector Anopheles sinensis.
Li F, Xu O, Zhou J … +3 more , He S, Chen B, He Z
Parasit Vectors · 2026 Mar · PMID 41872964 · Full text
BACKGROUND: Olfactory detection of host odors is fundamental to mosquito host-seeking behavior. Although the olfactory pathways of model species such as Anopheles gambiae have been well characterized, the molecular basis...
BACKGROUND: Olfactory detection of host odors is fundamental to mosquito host-seeking behavior. Although the olfactory pathways of model species such as Anopheles gambiae have been well characterized, the molecular basis of human odor detection in Anopheles sinensis, an important malaria vector in Asia with opportunistic feeding habits, remains poorly understood. This study systematically investigates the functional role of the odorant-binding protein AsOBP21f in this process. METHODS: AsOBP21f was cloned and characterized using bioinformatics, quantitative reverse transcription PCR (RT-qPCR), and phylogenetic analyses. Recombinant AsOBP21f protein was expressed and purified for fluorescence competitive binding assays with 35 human odorants. Molecular docking was performed to elucidate ligand-binding interactions. Electroantennogram (EAG) recordings and behavioral assays were conducted to evaluate mosquito responses to high-affinity ligands. RNA interference (RNAi) knockdown was used to assess the functional role of AsOBP21f in host-seeking and blood-feeding behavior. RESULTS: AsOBP21f was predominantly expressed in olfactory tissues of mosquito females, including the antennae and proboscis. Its protein exhibited notable selectivity for hydrophobic odor molecules with C10-C15 carbon chains, and had strong binding affinities for methyl tridecanoate, dodecanal, decanal, and pentadecanoic acid. Behavioral experiments further demonstrated dose-dependent effects of these ligands; methyl tridecanoate showed significant attraction, while dodecanal exhibited clear repellency. RNAi-mediated silencing of AsOBP21f significantly reduced the antennal electrophysiological response of mosquito females to host odors and markedly decreased blood-feeding success. CONCLUSIONS: These results highlight the role of AsOBP21f in host-seeking behavior through the detection of human odors, such as methyl tridecanoate, in An. sinensis, providing a potential target for malaria control.
Assessment of environmental contamination with Echinococcus spp. through DNA detection in free-roaming canid feces and soil in human echinococcosis hotspots from the Three-River-Source Region of the Qinghai-Tibet Plateau, China.
Zhang X, Li Z, Fu Y … +6 more , Ma Y, Shen X, Duo H, Guo Z, Zheng Y, Jian Y
Parasit Vectors · 2026 Mar · PMID 41872962 · Full text
BACKGROUND: The Three-River-Source Region of the Qinghai-Tibet Plateau is a hyperendemic focus for echinococcosis, with Echinococcus granulosus, E. multilocularis, and E. shiquicus circulating between definitive canid ho...
BACKGROUND: The Three-River-Source Region of the Qinghai-Tibet Plateau is a hyperendemic focus for echinococcosis, with Echinococcus granulosus, E. multilocularis, and E. shiquicus circulating between definitive canid hosts (dogs and foxes) and intermediate hosts (livestock and rodents). However, the extent of environmental contamination by Echinococcus eggs remains understudied and poses significant risks to human and animal health. METHODS: From 2019 to 2021, we collected 631 canid fecal samples (296 from dogs and 335 from foxes) and 398 adjacent soil samples across endemic counties in the Three-River-Source Region of the Qinghai-Tibet Plateau. Multiplex real-time PCR was employed to detect Echinococcus species DNA in feces and soil samples. RESULTS: The overall Echinococcus prevalence in canid feces was 7.13% (45/631), with 3.01% in E. multilocularis (19/631), 2.06% in E. granulosus (13/631), and 2.06% in E. shiquicus (13/631). Foxes presented increased E. multilocularis (3.88%, 13/335) and E. shiquicus (2.69%, 9/335) infections, whereas dogs presented increased E. granulosus prevalence (2.70%, 8/296). Soil contamination with Echinococcus species was detected in 2.51% (10/398) of the samples. The primary contaminants were E. multilocularis and E. shiquicus (1.01% each, 4/398), whereas E. granulosus was less frequent (0.50%, 2/398). Moreover, the soil near fox feces was contaminated with both E. multilocularis and E. shiquicus, whereas the dog-associated soil was contaminated with all three species. CONCLUSIONS: This study suggests widespread environmental deposition of Echinococcus eggs on the Qinghai-Tibet Plateau, driven by canid defecation. If these eggs remain viable, their persistence in soil would indicate a potential zoonotic transmission risk, highlighting the need for integrated control strategies targeting both domestic and wild canids.
Nanoscaffold-based 3D human liver spheroids for predictive hepatotoxicity screening of antimalarial compounds from the global health priority box.
Wu L, Vllasaliu D, Mabayoje DA … +2 more , Aspinall A, Raimi-Abraham BT
Parasit Vectors · 2026 Mar · PMID 41872940 · Full text
BACKGROUND: Drug-induced liver injury (DILI) remains a significant barrier to the safe and efficient use of antimalarial medicines. Many promising compounds fail in late-stage development or post-marketing owing to unfor...
BACKGROUND: Drug-induced liver injury (DILI) remains a significant barrier to the safe and efficient use of antimalarial medicines. Many promising compounds fail in late-stage development or post-marketing owing to unforeseen toxicity, particularly DILI. Incorporating a predictive hepatotoxicity assessment is therefore critical to reduce clinical risk and development costs. The Medicines for Malaria Venture (MMV) Global Health Priority Box (GHPB) provides a library of compounds with demonstrated or potential antimalarial activity, yet their hepatotoxicity risk remains poorly defined. Our early work developed and validated a nanoscaffold-based three-dimensional (3D) liver spheroid platform. Here, we apply this validated model for the first time to assess the hepatotoxicity of clinically used and candidate antimalarial GHPB compounds. METHODS: Our validated nanoscaffold-based 3D liver spheroid platform was used to evaluate the hepatotoxicity of approved antimalarial drugs of known liver toxicity (quinine, primaquine, amodiaquine, sulfadoxine/pyrimethamine, and artemisinin) and six GHPB candidate compounds. Half maximal inhibitory concentration (IC)-derived data from the approved antimalarial drugs were used to generate a reference framework on the basis of established DILI classifications, which was then applied to categorize the GHPB candidate compounds relative to hepatotoxic risk. RESULTS: Our nanoscaffold-based 3D liver spheroid platform accurately reproduced the known DILI rankings of the approved antimalarials, confirming its predictive validity. Using these referenced IC-derived profiles, candidate compounds from the GHPB were classified into distinct hepatotoxicity categories, ranging from low: MMV1167451 (compound 01) and MMV020192 (compound 02), moderate: MMV1797658 (compound 03) and MMV1435700 (compound 04), to high: MMV006344 (compound 05) and MMV006931 (compound 06) risk, demonstrating the model's capacity to support early-stage animal-free antimalarial hepatotoxicity screening. CONCLUSIONS: This study demonstrates the translational application of a validated nanoscaffold-based 3D human liver spheroid model for antimalarial drug in vitro hepatotoxicity assessment. By establishing a reference framework from clinically approved antimalarials and applying it to candidate compounds from the MMV GHPB, our platform enabled early classification of hepatotoxicity risk using a human-relevant, non-animal method. The findings support the integration of advanced 3D in vitro systems into antimalarial drug discovery pipelines to improve safety prediction, reduce reliance on animal testing, and accelerate the development of safer, more effective antimalarial therapies.
Leishmania infantum in red foxes (Vulpes vulpes): from clinical findings to cytokine expression.
Alves MH, Carbonara M, Palazzo N … +8 more , Gernone F, Louzada-Flores VN, Camarda A, Prioletti M, Dantas-Torres F, Bezerra-Santos MA, Mendoza-Roldan JA, Otranto D
Parasit Vectors · 2026 Mar · PMID 41872928 · Full text
BACKGROUND: The life cycle of Leishmania infantum is maintained mainly in dogs in anthropogenic environments and in many other wild animals in the sylvatic cycle. The ecological plasticity of some wild canids facilitates...
BACKGROUND: The life cycle of Leishmania infantum is maintained mainly in dogs in anthropogenic environments and in many other wild animals in the sylvatic cycle. The ecological plasticity of some wild canids facilitates their role as hosts for Leishmania spp. in different endemic regions. Although red foxes (Vulpes vulpes) frequently test positive for L. infantum in Europe, little is known about their clinical presentation, immune response, or treatment outcomes. This study investigated the prevalence, clinical, and immunological features of L. infantum infection in foxes from southern Italy, complemented by an in vitro evaluation of cytokine responses in fox macrophages. METHODS: Wild foxes from a wildlife rehabilitation center in southern Italy were molecularly and serologically screened for L. infantum. One sick fox underwent a complete diagnostic confirmation, treatment, and follow-up through hematological, biochemical, cytological, and molecular evaluations. In addition, peripheral blood mononuclear cells (PBMCs) isolated from a healthy fox were differentiated into macrophages and experimentally infected with L. infantum to assess early host-parasite interactions and cytokine gene expression profiles at two time points (4 h and 48 h). RESULTS: Overall, 13 out of 54 foxes (24.1%) were molecularly positive for L. infantum, with a prevalence of 25% (5/20) in necropsied animals and 22% (9/41) in live animals. One individual tested seropositive for L. infantum and Ehrlichia sp. using the SNAP Leish 4Dx test (2.4%, 1/41). The sick fox treated with meglumine antimoniate and allopurinol showed marked clinical and laboratory improvement. In the in vitro evaluation, the percentage of infected macrophages decreased from 32.8% at 4 h (2.25 parasites/cell) to 21.5% at 48 h (2 parasites/cell). Cytokine gene expression at 4 h and 48 h showed an increase in interleukin-6 (IL-6) (0.164-0.552) and IL-10 (0.828-4.245), stable IL-4 (0.505-0.708), a decrease in IL-12 (1.793-1.223) and IFN-γ (1.507-0.613), and consistently low TNF-α (0.377-0.411). CONCLUSIONS: The present study confirmed a high L. infantum prevalence of infection in red foxes from southern Italy. Serological findings herein and in the literature, together with in vitro cytokine gene expression, suggested that most foxes may remain subclinically infected. The high molecular positivity and the synanthropic nature of red foxes reinforce their role as reservoirs of L. infantum in endemic areas.
Improved serological testing for bovine schistosomiasis in Eastern Africa.
Tóth V, Gasan TA, Crooks B … +7 more , Nzalawahe J, Juhász A, LaCourse JE, Stothard JR, Ame SM, Hu W, Gobert GN
Parasit Vectors · 2026 Mar · PMID 41872927 · Full text
BACKGROUND: In East Africa, bovine schistosomiasis, although common, is poorly appreciated and managed, detrimentally impacting upon livestock health. In certain settings, bovine schistosomiasis may be involved in zoonot...
BACKGROUND: In East Africa, bovine schistosomiasis, although common, is poorly appreciated and managed, detrimentally impacting upon livestock health. In certain settings, bovine schistosomiasis may be involved in zoonotic transmission of human schistosomiasis. Better disease management and more effective control of bovine schistosomiasis require the development of sensitive and specific serological screening and rapid diagnostic tools. METHODS: We developed an enzyme-linked immunosorbent assay (ELISA) for Schistosoma bovis detection in cattle, utilizing nine shortlisted potential diagnostic protein targets. These shortlisted candidates, STI, IPP, OP, PGK1, COG, PDZ, and Sbp80 (as three fragments), were identified from Schistosoma japonicum homologs already reported with the highest diagnostic potential. In S. bovis, these proteins participate in various biological processes, including metabolic pathways, transcriptional regulation, glycolysis, phosphorylation, and cell signalling, although their real diagnostic potential has not been explored until now. RESULTS: The ELISA was optimized using bovine blood serum samples from regions in Tanzania and validated for sensitivity and specificity. Two targets of specific focus, Conserved Oligomerix Golgi complex subunit 4 (COG) and a domain of the cysteine protease calpain (Sbp80), achieved the highest specificity and sensitivity among the recombinant proteins, with 92% and 88% sensitivity and 100% and 80% specificity, respectively. We further evaluated the COG-based and calpain-based ELISA on further "real-world" bovine serum samples from abattoir sites in Zanzibar, detecting S. bovis in 59.1% of tested animals. CONCLUSIONS: Both COG and calpain are promising candidates for serological screening and later inclusion in portable diagnostic tests for S. bovis infection in cattle. Such future diagnostic assays will enable better point-of-detection monitoring, and once scalable, aid in the control of disease in cattle.
Intraspecific geographical variability of Phlebotomus perniciosus assessed by MALDI-TOF MS protein profiling.
Dvorak V, Maia C, Marmé R … +14 more , Risueño J, Pérez-Cutillas P, Berriatua E, Sevila J, Mekarnia N, Prudhomme J, Randriananambinintsoa FJ, Depaquit J, Bernardini I, Mangiapelo C, Bongiorno G, Ivović V, Adam K, Halada P
Parasit Vectors · 2026 Mar · PMID 41872924 · Full text
BACKGROUND: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) protein profiling has emerged over the last decade as a method of choice for species identification of many medicall...
BACKGROUND: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) protein profiling has emerged over the last decade as a method of choice for species identification of many medically important arthropods. However, the influence of intraspecific variability on the performance of this popular technique has seldom been tested. This study provides the first standardized comparison of different geographical populations of Phlebotomus perniciosus, a vector of Leishmania infantum and Toscana virus in the western Mediterranean, by MALDI-TOF MS protein profiling. METHODS: Phlebotomus perniciosus males were collected in five countries (Portugal, Spain, France, Italy, Croatia) that represent most of its distribution in Europe. All samples were trapped, stored and processed according to a highly standardized protocol to avoid effects other than geographical origin on their protein spectra acquired by MALDI-TOF MS protein profiling. The obtained protein spectra were compared with laboratory-reared specimens of Ph. perniciosus. RESULTS: Twenty-two analysed specimens from five geographical populations provided protein spectra that were highly similar, species-specific and clustering according to their quality. No grouping according to geographical origin was observed, and the protein spectra of field-collected specimens showed similar composition and complexity to spectra from Ph. perniciosus laboratory colony-reared in captivity for several decades. CONCLUSIONS: Our findings demonstrate that in samples of a same sex, with the same collection method and storage time, MALDI-TOF MS protein profiling does not reflect the geographical origin of analysed specimens, confirming the value of this technique for high-fidelity and reproducible species identification of sand flies regardless of their geographical origin.
Dual functions of the Aedes aegypti ecdysone receptor in dengue virus replication and reproduction control.
Weng SC, Lin YS, Tsao PN … +1 more , Shiao SH
Parasit Vectors · 2026 Mar · PMID 41866575 · Full text
BACKGROUND: The ecdysone receptor (EcR) is a central regulator of mosquito physiology, best known for its role in vitellogenesis. However, its contribution to antiviral defense and dengue virus (DENV) replication in Aede...
BACKGROUND: The ecdysone receptor (EcR) is a central regulator of mosquito physiology, best known for its role in vitellogenesis. However, its contribution to antiviral defense and dengue virus (DENV) replication in Aedes aegypti remains poorly understood. METHODS: RNA interference was used to silence Aedes aegypti EcR (AaEcR). Effects on DENV replication, immune gene expression, ovarian development, vitellogenin (Vg) synthesis, and target of rapamycin (TOR) pathway activity were assessed using molecular, cellular, and phenotypic analyses. RESULTS: Silencing AaEcR markedly suppressed DENV replication, viral protein expression, and virion production. These antiviral effects coincided with increased expression of antimicrobial peptides and activation of innate immune pathways, indicating that AaEcR facilitates viral replication by dampening host defenses. In addition, AaEcR proved essential for reproductive output. Knockdown impaired ovarian development, reduced follicle size and number, and lowered egg production by ~30%, although egg viability was unaffected. At the molecular level, AaEcR depletion strongly reduced Vg transcription and protein abundance, along with decreased phosphorylation of S6 kinase, suggesting that AaEcR promotes fecundity through both transcriptional activation and TOR-Vg signaling. CONCLUSIONS: AaEcR functions as a dual regulator of mosquito biology, suppressing antiviral immunity while enhancing reproductive output. This tradeoff between immunity and fecundity highlights AaEcR as a promising molecular target for vector control. Disrupting EcR signaling could simultaneously reduce mosquito population size and limit arboviral transmission, offering a potential strategy for integrated management of mosquito-borne diseases.
Development and evaluation of an assay for the detection of tick-borne encephalitis virus RNA via real-time PCR with reverse transcription.
Sharova A, Safonova M, Dolgova A … +12 more , Shabalina A, Popova M, Arbuzova T, Schirobokova S, Gladkikh A, Naydenov D, Sbarzaglia V, Klyuchnikova E, Kholodilov I, Karganova G, Ramsay E, Dedkov V
Parasit Vectors · 2026 Mar · PMID 41866562 · Full text
BACKGROUND: Tick-borne encephalitis virus (TBEV, Orthoflavivirus encephalitidis) is an arbovirus of the family Flaviviridae. It is the etiological agent of tick-borne encephalitis (TBE), a severe disease affecting the ce...
BACKGROUND: Tick-borne encephalitis virus (TBEV, Orthoflavivirus encephalitidis) is an arbovirus of the family Flaviviridae. It is the etiological agent of tick-borne encephalitis (TBE), a severe disease affecting the central nervous system. Among arboviral infections, TBE represents the greatest burden in northern Eurasia, both in terms of emerging infection risk and mortality. Globalization and climate change increase the risk of TBEV introduction into nonendemic countries. They may also lead to the emergence of new viral variants featuring increased virulence for humans or altered antigenic characteristics. Hence, sensitive and specific TBEV detection methods are needed not only for diagnostics but also for One Health approach goals (surveillance and identification of viral sources in the environment). METHODS: Here, we describe a newly developed reverse transcription PCR (RT‒PCR) assay for TBEV detection. The assay was developed and evaluated using armored RNA positive control particles (ARCs). The assay was evaluated using several sample types: (1) a panel of heterologous viral and bacterial RNA/DNA; (2) RNA from TBEV strains isolated in different years in various Russian regions; and (3) RNA from TBEV-positive and TBEV-negative ticks (collected in northwest Russia). RESULTS: The limit of detection (LOD) of the assay is 10 copies/mL (20 copies/reaction) of TBEV RNA. The developed demonstrated 100% analytical specificity. The assay was compared with the two most commonly used Russian commercial kits for TBEV diagnostics. CONCLUSIONS: The results indicate that the developed RT‒PCR assay is a reliable and competitive method for the detection of TBEV RNA, which establishes its value as a tool for diagnosing and monitoring the virus.
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