Parasit Vectors [JOURNAL]
Sun
200 papers
Long-read transcriptomics corrects Trichomonas vaginalis intron annotations and refines transcript-end features.
Yeh YM, Cheng WH, Huang KY … +7 more , Lee CC, Ong SC, Luo HW, Syu JW, Chiu CH, Huang PJ, Tang P
Parasit Vectors · 2026 Jun · PMID 42337815 · Full text
BACKGROUND: Trichomonas vaginalis causes the most prevalent non-viral sexually transmitted infection worldwide. Despite its large genome (181.5 Mb; 36,310 predicted protein-coding genes in NYU_TvagG3_2), intron annotatio...
BACKGROUND: Trichomonas vaginalis causes the most prevalent non-viral sexually transmitted infection worldwide. Despite its large genome (181.5 Mb; 36,310 predicted protein-coding genes in NYU_TvagG3_2), intron annotations remain limited and inconsistently validated. A recent short-read RNA-seq study reported 63 putative active introns, but short reads can misassign splice boundaries and cannot resolve complete transcript structures. METHODS: We integrated Oxford Nanopore direct RNA sequencing (DRS), ONT cDNA long-read sequencing, and Illumina RNA-seq to refine intron annotations, transcript-end features, and UTR boundaries in T. vaginalis. Candidate introns were validated by targeted PCR and Sanger sequencing, and representative splicing events were further assessed using public SRA datasets. RESULTS: Starting from 31 historically annotated introns, motif-guided long-read screening and orthogonal validation identified 17 additional validated introns, increasing the curated set to 48 confirmed introns. Among these 17 events, three were previously unrecognized in the current NYU_TvagG3_2 reference annotation. We also corrected five reported loci, including two false-positive introns, two splice-coordinate misannotations, and one gene-sequence error. DRS further supported transcript termination site mapping, UAAA polyadenylation-signal profiling relative to poly(A) addition sites, and single-molecule poly(A)-tail estimation. StringTie mixed-mode assemblies provided updated UTR boundaries for intron-bearing transcripts and transcripts without curated introns. CONCLUSIONS: This study provides a rigorously validated, long-read-refined resource of intron annotations, UTR boundaries, and UAAA-guided transcript-end features for T. vaginalis, together with a reproducible workflow for non-model protists. These refinements improve the current reference annotation and support future studies of functional genomics, parasite biology, pathogenesis, and diagnostic development.
A descriptive assessment of mitochondrial COI genetic diversity and dengue and chikungunya RNA detection in Aedes aegypti across eight provinces in Thailand.
Siriyasatien P, Intayot P, Boonserm R … +6 more , Ampol R, Sutthanont N, Silakom N, Suwanbamrung C, Schmidt-Chanasit J, Phumee A
Parasit Vectors · 2026 Jun · PMID 42337626 · Full text
BACKGROUND: Aedes aegypti is the principal vector of several medically important arboviruses, including dengue virus (DENV) and chikungunya virus (CHIKV), both of which remain endemic in Thailand. However, studies on arb...
BACKGROUND: Aedes aegypti is the principal vector of several medically important arboviruses, including dengue virus (DENV) and chikungunya virus (CHIKV), both of which remain endemic in Thailand. However, studies on arbovirus surveillance and mitochondrial genetic diversity of Ae. aegypti populations across broad geographic scales remain limited. This study aimed to assess the detection of DENV and CHIKV and characterize the mitochondrial genetic diversity of Ae. aegypti across multiple regions of Thailand. METHODS: A total of 303 adult Ae. aegypti mosquitoes collected from eight provinces across five geographic regions of Thailand were screened for DENV and CHIKV RNA. Mitochondrial cytochrome c oxidase subunit I (COI) genetic diversity was assessed using haplotype network analysis and analysis of molecular variance (AMOVA). RESULTS: CHIKV RNA was detected in 51 mosquitoes (16.8%) from four provinces, with the highest detection rates observed in Prachuap Khiri Khan and Bangkok. DENV RNA was not detected in any sample. COI analysis revealed moderate to high mitochondrial haplotype diversity and geographic variation in haplotype distribution among populations. Both widely shared and province-specific haplotypes were identified. AMOVA indicated that most genetic variation occurred within populations (93.19%), with significant genetic differentiation among populations (ΦST = 0.068, P < 0.001). CONCLUSIONS: CHIKV RNA was detected in Ae. aegypti populations from multiple regions of Thailand, whereas DENV RNA was not detected. Mitochondrial COI analysis revealed substantial haplotype diversity and geographic variation among populations. These findings contribute to current knowledge of arbovirus occurrence and mosquito genetic diversity in Thailand and provide a foundation for future vector surveillance studies.
Effects of insect-specific viruses on transmission, infection, and replication of arboviruses in co-infected mosquitoes: a systematic review.
Sibanda-Makuvise A, Masoto N, Terblanche GIDP … +3 more , Ralepeli P, Botha J, Burt FJ
Parasit Vectors · 2026 Jun · PMID 42337587 · Full text
BACKGROUND: Climate change, globalization, and urbanization continue to reshape the ecology of vector-borne diseases, allowing mosquito-transmitted arboviruses to expand into previously non-endemic areas. Increasing inse...
BACKGROUND: Climate change, globalization, and urbanization continue to reshape the ecology of vector-borne diseases, allowing mosquito-transmitted arboviruses to expand into previously non-endemic areas. Increasing insecticide resistance, ecological disruption, and declining efficacy of conventional vector control strategies have prompted an interest in microbe-based alternatives. Insect-specific viruses (ISVs), a group of viruses restricted to replicating in arthropods like mosquitoes, have emerged as potential modulators of mosquito vector competence. This systematic review assesses current in vivo evidence on the effects of ISVs on arboviral replication, infection, and transmission, for the purpose of considering their potential application as biocontrol agents for arboviruses.Please confirm if the author names are presented accurately and in the correct sequence (given name, middle name/initial, family name). METHODS: A systematic search strategy was applied to PubMed, Scopus, ScienceDirect, and Google Scholar to identify relevant studies. The selection process followed PRISMA guidelines and PICO-based inclusion criteria. RAYYAN AI was used to remove duplicates, for abstract and full text screening. Only in vivo studies analyzing interactions between ISVs and medically relevant arboviruses in mosquitoes were retained. Study quality was assessed using the Mixed Methods Appraisal Tool (MMAT), and data extraction followed JBI guidelines. RESULTS: A total of 3386 studies were found using the search strategy, of these 15 studies met the inclusion criteria. The effects of ISVs on co-infecting arboviruses were highly variable, depending on mosquito species, ISV strain, route of infection, and the phylogenetic relationship between the ISV and the arbovirus. Cell-fusing agent virus (CFAV), Nhumirim virus (NHUV), Palm Creek virus (PCV), Culex flavivirus (CxFV), Eilat virus (EILV), Espirito Santo virus (ESV), Yichang virus (YCV), Anopheles gambiae densovirus (AgDNV), and Aedes aegypti densovirus (AaeDV) showed suppression in either one or more of the parameters of vector competence used, such as replication, transmission, and infection rate, likely associated with mechanisms consistent with superinfection exclusion or competition for shared cellular resources. In contrast, Phasi Charoen-like virus (PCLV) and Humaita-Tubiacanga virus (HTV) enhanced flavivirus infection and transmission in Aedes aegypti, suggesting that some ISVs may facilitate, rather than inhibit, arbovirus spread. Additionally, in some studies where infection routes differed, neutral or inconsistent interactions were observed. CONCLUSIONS: ISVs act as context-dependent modulators of arboviral dynamics in mosquitoes. While some indicate biological inhibitory potential, others enhance viral replication or have negligible effects, underlining the importance of meticulous viral selection and ecological risk assessment before considering ISVs as biocontrol candidates. Carefully designed experimental, mechanistic and semi-field evaluations are important for ISVs to be considered as biocontrol agents within integrated vector management programs.
Borrelia theileri infection in beef and dairy cattle in Israel: molecular detection and co-infection with bovine piroplasmids.
Shwartz D, Salant H, Nachum-Biala Y … +8 more , Simon N, Leszkowicz-Mazuz M, Yasur-Landau D, Gleser D, Klement E, Rudoler N, Eliahoo E, Baneth G
Parasit Vectors · 2026 Jun · PMID 42337585 · Full text
BACKGROUND: Tick-borne relapsing fever is an infectious disease caused by spirochetes of the genus Borrelia, leading to fever and spirochetemia in humans and animals. Borrelia theileri is the agent of bovine relapsing fe...
BACKGROUND: Tick-borne relapsing fever is an infectious disease caused by spirochetes of the genus Borrelia, leading to fever and spirochetemia in humans and animals. Borrelia theileri is the agent of bovine relapsing fever, which is transmitted by ixodid ticks of the genus Rhipicephalus and has been reported to cause mild disease in cattle. It has been infrequently reported in several countries over a broad geographic area; however, it has not been reported in Israel previously. METHODS: Blood samples were collected from beef and dairy cattle in 23 locations in Israel. Real-time and conventional PCR were used to detect Borrelia spp. and co-infection with bovine piroplasmids. PCR products were sequenced, and phylogenetic analysis of the B. theileri sequences was performed. Positive cattle were identified in a limited number of locations with no clear spatial clustering. RESULTS: Borrelia theileri DNA was detected in 6 out of 439 (1.4%) blood samples. Of these, four were from beef and two from dairy cattle. No significant differences were found according to age (P = 0.642) and production type (P = 0.802) among the B. theileri-positive cattle. Phylogenetic analysis showed clustering of the cattle-derived isolate together with B. theileri amplified from ixodid ticks, supporting a potential transmission cycle involving cattle and Rhipicephalus spp. ticks. Theileria annulata and Babesia bigemina DNA was detected in 11 (4.1%) and one (0.4%) of 268 unvaccinated cattle, respectively. Co-infection with Theileria annulata was found in one beef and one dairy cattle. CONCLUSIONS: Tick-borne relapsing fever is present in the cattle population of Israel. Co-infection of B. theileri and bovine piroplasmids may drive clinical disease and financial losses in beef and dairy cattle. This is the first report of B. theileri infection in Israel. Future control programs should address the exposure of both beef and dairy cattle to ticks and tick-borne diseases.
Nationwide seroepidemiology of canine exposure to Ehrlichia canis and Babesia spp. in Portugal (2015-2025): One Health biosentinel surveillance.
Lopes R, de Carvalho L, Silva V … +5 more , Fernandes C, Lopes AP, Duarte EL, Cardoso L, Coelho AC
Parasit Vectors · 2026 Jun · PMID 42332825 · Full text
BACKGROUND: Ehrlichia canis and canine Babesia spp. are widely distributed tick-borne pathogens of veterinary and One Health relevance. Contemporary nationwide data on canine exposure and associated determinants in Portu...
BACKGROUND: Ehrlichia canis and canine Babesia spp. are widely distributed tick-borne pathogens of veterinary and One Health relevance. Contemporary nationwide data on canine exposure and associated determinants in Portugal are limited. This study aimed to estimate seropositivity proportions and explore epidemiological determinants of exposure to E. canis and Babesia spp. in clinically suspected dogs from Portugal over an 11-year period (2015-2025). METHODS: Serum samples from 2960 dogs collected between 2015 and 2025 were analysed using commercial enzyme-linked immunosorbent assay kits to detect immunoglobulin G antibodies to E. canis and Babesia spp. Associations with demographic and geographic variables were assessed using chi-square and Fisher's exact tests. Univariable and multivariable logistic regression were used to identify potential risk factors (P < 0.05), and model performance was evaluated using the Hosmer-Lemeshow test, Nagelkerke's R, and the area under the receiver operating characteristic curve. RESULTS: Overall seropositivity was 4.0% (116/2,872) for E. canis and 12.0% (337/2,818) for Babesia spp. Borderline results accounted for 3.0% (88/2,960) and 4.8% (142/2,960), respectively. E. canis seropositivity varied significantly by Nomenclature of Territorial Units for Statistics level 2 region (P < 0.001), with highest values in the Algarve (15.3%; odds ratio [OR] = 4.3, P < 0.001) and Setúbal Peninsula (50.0%; OR = 23.9, P = 0.025). Age was associated with E. canis exposure (P = 0.014), with increased odds in dogs aged 6 to < 11 years and ≥ 11 years (both OR = 2.1, P < 0.05). No significant geographical association was observed for Babesia spp. (P = 0.803), and sex and age were not significant predictors. Seropositivity to Babesia spp. was a risk factor for seropositivity to E. canis (OR = 3.6, P < 0.001). Multivariable models retained no independent predictors (Nagelkerke R = 0.15; area under the curve = 0.71). CONCLUSIONS: This study provides a nationwide, long-term retrospective assessment of serological exposure to E. canis and Babesia spp. among clinically suspect dogs in Portugal. Exposure to E. canis showed marked regional heterogeneity, particularly in southern Portugal, whereas Babesia spp. showed no significant regional association. Co-seropositivity, although uncommon, is consistent with shared tick-borne exposure pathways. These findings support risk-based tick control and continued surveillance within a One Health framework.
Projected distributions of 18 mosquito species in the Republic of Korea under climate change scenarios.
Ryu J, Choi KS
Parasit Vectors · 2026 Jun · PMID 42324574 · Full text
BACKGROUND: Climate change is altering mosquito distributions and may reshape the risk of mosquito-borne diseases in the Republic of Korea (ROK). However, nationwide, multi-species projections for medically important mos...
BACKGROUND: Climate change is altering mosquito distributions and may reshape the risk of mosquito-borne diseases in the Republic of Korea (ROK). However, nationwide, multi-species projections for medically important mosquitoes remain limited. METHODS: We compiled 1,969 spatially filtered occurrence records for 18 mosquito species and developed species distribution models using MaxEnt. Environmental predictors included bioclimatic, topographic, and land cover variables. Future distributions were projected for the 2030s, 2050s, and 2070s under SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios using MIROC6 climate data. A Climate Change Vulnerability Index (CCVI) was calculated to compare species-specific range expansion and contraction. RESULTS: Current habitat suitability patterns grouped the 18 species into nationwide, northern-preferring, southwestern-preferring, and southern-preferring distribution types. Topographic Wetness Index (36.6%), elevation (18.6%), and land cover type (18.4%) contributed more strongly to model performance than climatic variables alone. Under SSP5-8.5 in the 2070s, Aedes albopictus and Culex tritaeniorhynchus were projected to expand suitable habitat by 183.4% and 236.5%, respectively, whereas northern-preferring Anopheles species showed marked habitat contraction. Anopheles pullus and Anopheles belenrae were projected to lose 100.0% of their suitable habitat under the highest-emission scenario. The CCVI classified five species, mainly Anopheles, as highly vulnerable, one species as moderately affected, and 12 species as range-expanding. CONCLUSIONS: These findings indicate that climate change may substantially reorganize mosquito communities in the ROK, reducing habitat suitability for several malaria vectors while expanding suitable areas for important arbovirus and Japanese encephalitis vectors. Adaptive surveillance and vector management should therefore integrate climate projections with local landscape and hydrological risk factors.
Photographic atlas of phlebotomine sand flies collected in north-west and central east Belize.
Rawlings NN, Bailey MS, Rodrigues BL … +3 more , Filho JDA, Ibáñez-Bernal S, Courtenay O
Parasit Vectors · 2026 Jun · PMID 42324561 · Full text
BACKGROUND: Morphological identification of phlebotomine sand flies in Belize has historically relied on greyscale illustrations and taxonomic keys, which can limit identification accuracy and accessibility for non-speci...
BACKGROUND: Morphological identification of phlebotomine sand flies in Belize has historically relied on greyscale illustrations and taxonomic keys, which can limit identification accuracy and accessibility for non-specialists. Building on our recent investigation of the spatiotemporal distribution of sand flies in the country, we provide a coloured pictorial guide to the species collected. METHODS: Sand flies were collected in north-west and central east Belize between 2023 and 2025 and identified morphologically using established taxonomic keys. Representative voucher specimens were deposited in the Coleção de Flebotomíneos (FIOCRUZ/COLFLEB), Belo Horizonte, Brazil. RESULTS: We present 65 coloured photomicrographs covering 20 species, including 18 previously reported in Belize and two species (Lutzomyia longipalpis and Psathyromyia soccula) recorded in the country for the first time. The guide highlights key diagnostic characters, including male genitalia, spermathecae, cibarium, and other external morphological features, and integrates both coloured and greyscale images. A dichotomous key to the collected species is also provided. CONCLUSIONS: This pictorial guide complements existing taxonomic resources and aims to improve consistency and accessibility of sand fly identification in Belize. The integration of coloured photomicrographs with conventional morphological keys provides a practical resource to support vector surveillance and future taxonomic work.
Emerging and regionally novel voltage-gated sodium channel mutations associated with pyrethroid resistance and altered binding affinity in Aedes albopictus (Skuse) from Northern Peninsular Malaysia.
Adilah-Amrannudin N, JunKai KT, Mohamad AF … +6 more , Ahmad AH, Salim H, Azzam G, Manap NN, Rahman S, Ishak IH
Parasit Vectors · 2026 Jun · PMID 42324557 · Full text
BACKGROUND: The application of synthetic insecticides is the primary means of controlling Aedes mosquitoes in Malaysia, but the efficacy of this method is undermined by the evolution of resistance. Aedes albopictus as on...
BACKGROUND: The application of synthetic insecticides is the primary means of controlling Aedes mosquitoes in Malaysia, but the efficacy of this method is undermined by the evolution of resistance. Aedes albopictus as one of the dominant and competent arboviral vectors has an elusive insecticide resistance status in different geographical regions of Northern Peninsular Malaysia. This underscores the importance of assessing the diverse types of insecticides used and their association with target-site resistance mechanism in this species, which forms the basis of the present study. METHODS: WHO bioassays were performed on Ae. albopictus larvae and adults from four localities (Penang and Perlis), towards 0.034 ppm temephos, 0.25% permethrin, 0.03% deltamethrin, 0.25% pirimiphos-methyl, and 0.1% propoxur. The partial voltage-gated sodium channel (vgsc) gene domain (DIIS6, DIIIS6, and DIVS6) of pyrethroid-exposed samples were subsequently genotyped through direct sequencing for single-nucleotide mutations, together with genetic variations and haplotype networks analysis. The predicted protein structures for the mutated regions and their binding affinities to pyrethroids were also evaluated using in silico docking. RESULTS AND DISCUSSIONS: Varying degrees of resistance were observed in all Penang and Perlis strains to all tested insecticides. Moreover, the detection of the F1534L mutation and newly discovered non-synonymous mutations (A1022S/P, E1041K, P1585R, and F1695L) suggest the progression of resistance alleles dissemination in these strains. The analysis of genetic variations, resistance allele distribution patterns, and haplotype networks showed evidence for multiple origins of these mutations. Data also revealed the discovered mutations affect the affinity of vgsc-binding proteins to pyrethroids. CONCLUSIONS: This study highlights the genotype-phenotype associations in Ae. albopictus and their genetic links to pyrethroid resistance, offering insights to strengthen vector control strategies in Malaysia.
Validation of a duplex real-time PCR (qPCR) in clinically classified dogs naturally infected with Leishmania infantum before and after specific treatment: preliminary results.
Gómez-Velasco C, Montoya A, Checa R … +7 more , Heredia-Caldeiro J, Barrera JP, Estévez-Sánchez E, Sarquis J, García-Rupérez D, Moraleda P, Miró G
Parasit Vectors · 2026 Jun · PMID 42324461 · Full text
BACKGROUND: Canine leishmaniosis, caused by Leishmania infantum, is a chronic vector-borne zoonosis with variable clinical manifestations, which complicates its diagnosis and monitoring. Although quantitative serology is...
BACKGROUND: Canine leishmaniosis, caused by Leishmania infantum, is a chronic vector-borne zoonosis with variable clinical manifestations, which complicates its diagnosis and monitoring. Although quantitative serology is the primary indirect diagnostic approach, polymerase chain reaction (PCR) is the most sensitive direct diagnostic method for confirming the infection by detecting Leishmania DNA in biological samples, but its performance varies according to the analysed tissue and molecular assay. This study aimed to validate a duplex real-time PCR assay and compare its diagnostic performance with a nested PCR in six different canine tissues, as well as to define the diagnostic value of non-invasive samples in clinical staging and monitoring in naturally infected dogs before and after specific treatment. METHODS: Leishmania nested PCR and quantitative PCR targeting the small subunit (SSU) ribosomal RNA (rRNA) gene were performed on lymph node, blood, oral and conjunctival swabs, urine and hair samples from 66 dogs (20 non-infected, 15 clinically healthy infected and 31 naturally infected sick dogs classified according to LeishVet clinical staging). Sick dogs classified as stage II-III were re-evaluated 30 days after therapy to assess clinical improvement and changes in parasite load during follow-up. RESULTS: Lymph node samples showed the highest sensitivity and parasite loads, correlating well with clinical severity, IFAT titres and albumin/globulin ratio. Among non-invasive samples, oral swabs showed the best performance, particularly in dogs with clinically relevant disease, while conjunctival swabs showed moderate sensitivity. By contrast, blood showed limited and stage-dependent diagnostic value, while urine and hair demonstrated very low sensitivity. Quantitative PCR showed slightly higher sensitivity than nPCR in most tissues, except for lymph node and blood samples. A C cut-off of 39.00 was applied to minimise non-specific amplification, which was particularly pronounced in urine qPCR, achieving 100% specificity across all other tissues. The qPCR showed a reaction efficiency of 85.4% (R = 0.997), with a limit of detection of 0.5 parasite equivalents/reaction. Parasite load increased significantly from stage I to stage II dogs, but did not differ between stages II and III. After treatment, clinical scores and parasite loads decreased significantly in lymph node, oral and conjunctival swab samples. CONCLUSIONS: PCR performance in canine leishmaniosis is strongly influenced by tissue, technique and clinical stage. nPCR should be the test of choice for diagnostic confirmation, with lymph node as the gold standard sample, while oral swabs represent the most reliable non-invasive alternative, particularly in dogs with clinically relevant disease. For clinical follow-up, qPCR is preferable due to its ability to monitor parasite load changes in appropriate tissues, particularly lymph node and oral swab samples. The limited reliability of PCR from non-invasive samples in early stages of infection reinforces the need for a multimodal diagnostic approach in the clinical management of canine leishmaniosis.
Molecular characterization of thioredoxin peroxidases 1 from Trichinella spiralis and its potential in generating protective immunity.
Tong M, Guo Z, Wang M … +10 more , Yang Y, Fu M, Gao Y, Ren J, Wang Z, Yu P, Zhou X, Liu H, Wang H, Wang H
Parasit Vectors · 2026 Jun · PMID 42323668 · Full text
BACKGROUND: Trichinella spiralis remains a significant food-borne parasitic threat with no licensed vaccine available. This study evaluated the vaccine potential of T. spiralis thioredoxin peroxidase 1 (Ts-TPx1). METHODS...
BACKGROUND: Trichinella spiralis remains a significant food-borne parasitic threat with no licensed vaccine available. This study evaluated the vaccine potential of T. spiralis thioredoxin peroxidase 1 (Ts-TPx1). METHODS: Recombinant Ts-TPx1 (rTs-TPx1) was expressed, purified, and characterized. Mice were immunized intraperitoneally with rTs-TPx1 plus ISA206, ISA206 alone, or PBS, and subsequently challenged orally with T. spiralis larvae. Systemic and intestinal immune reponses, protection efficacy, intestianl barrier function, and pathological changes in the murine intestine and diaphragm muscle were subsequently assessed. RESULTS: Ts-TPx1 belongs to the 2-Cys peroxiredoxin family. Native Ts-TPx1 is expressed across key lifecycle stages, predominantly localizing to the parasite surface and stichosome. rTs-TPx1 immunization elevated serum levels of Ts-TPx1-specific IgG, IgG1, and IgG2a, with IgG1 levels higher than IgG2a, and increased splenocyte secretion of specific INF-γ and IL-4. The vaccine conferred significant protection, reducing intestinal adult worm burden by 65.0% and muscle larval burden by 61.8%. It also enhanced intestinal mucosal immunity, as evidenced by increased sIgA and Muc2 levels, and ameliorated intestinal and diaphragm muscle pathology. CONCLUSIONS: rTs-TPx1 immunization elicited specific intestinal mucosal immunity and Th2-biased mixed Th1/Th2 systemic protective response, establishing it as a promising vaccine candidate against Trichinella infection.
Mosquito-based xenosurveillance reveals circulation of Anaplasma and Neoehrlichia in livestock at a human-wildlife interface in Kenya.
Getange D, Mukaratirwa S, Esibi O … +4 more , Yuko E, Kabii J, Khogali R, Villinger J
Parasit Vectors · 2026 Jun · PMID 42321905 · Full text
BACKGROUND: Xenosurveillance, which uses blood-feeding insects as biological samplers, is an emerging non-invasive approach for monitoring pathogens circulating among humans, livestock, and wildlife. However, its applica...
BACKGROUND: Xenosurveillance, which uses blood-feeding insects as biological samplers, is an emerging non-invasive approach for monitoring pathogens circulating among humans, livestock, and wildlife. However, its application to livestock-associated bacterial pathogens at human-animal-wildlife interfaces remains underexplored. We investigated whether mosquito blood meals could be used to detect tick-borne bacterial pathogens circulating in livestock in Kenya. METHODS: We collected 4673 mosquitoes, belonging to Culex, Anopheles, Aedes, Mansonia, and Coquillettidia genera around livestock enclosures in Kajiado and Naivasha counties, Kenya, using CO₂-baited CDC miniature light traps. Traps were selected to maximise species diversity, and as light traps capture fewer engorged mosquitoes than resting traps, only 56 blood-fed individuals (1.2%) were collected and processed as whole-specimen homogenates and analysed for vertebrate blood-meal sources using cytochrome b sequencing. In total, 303 mosquito pools, including blood-fed individuals processed as single-mosquito pools, were screened for Anaplasma, Ehrlichia, Rickettsia, Theileria, and Babesia using PCR-high-resolution melting analysis and confirmatory sequencing. RESULTS: All pathogen-positive detections were exclusively from blood-fed individuals. We detected Anaplasma marginale in Culex pipiens (1/150; 0.7%) and Aedes hirsutus (2/11; 18.2%), Anaplasma sp. in Cx. pipiens (2/150; 1.4%) and Ae. hirsutus (1/11; 9.1%), and Candidatus Neoehrlichia mikurensis in Mansonia africana (2/50; 4%). Pathogen detections showed strong host concordance, where A. marginale was associated with cattle-derived blood meals and Anaplasma sp. with goat-derived blood meals, while Candidatus Neoehrlichia mikurensis was detected in Mn. africana that had fed on cattle and on a host that could not be determined. CONCLUSIONS: Our results provide preliminary evidence that mosquito-based xenosurveillance can detect tick-borne bacterial pathogens circulating in livestock at human-wildlife interfaces in Kenya. The strong concordance between pathogen identity and vertebrate host in blood-fed mosquitoes supports the biological plausibility of this approach. Notably, detection of Ca. Neoehrlichia mikurensis represents the first report of this zoonotic pathogen in mosquitoes in Africa, highlighting the One Health relevance of xenosurveillance in identifying settings, where pathogen circulation and cross-interface feeding coincide. Mosquito-derived sampling has potential to complement existing surveillance tools in agro-pastoral systems, where direct host sampling is difficult or costly.
Efficacy of volatile pyrethroid spatial repellents to reduce exposure to mosquito and sand fly vectors and human infection risk: a systematic review and meta-analysis.
Rawlings NN, Bailey MS, Courtenay O
Parasit Vectors · 2026 Jun · PMID 42316282 · Full text
BACKGROUND: Volatile pyrethroid spatial repellents (VPSRs) have emerged as promising complementary tools for vector control. This systematic review and meta-analysis evaluated the protective efficacy (PE) of VPSRs agains...
BACKGROUND: Volatile pyrethroid spatial repellents (VPSRs) have emerged as promising complementary tools for vector control. This systematic review and meta-analysis evaluated the protective efficacy (PE) of VPSRs against mosquito- and sand-fly-borne human infections, and against vector numbers in traps. METHODS: Clinical infection and entomological studies that evaluated VPSRs against human infection with Plasmodium, arboviruses (Dengue and Zika), and Leishmania, and against their respective vectors, were systematically reviewed. Random-effects meta-analyses estimated pooled PE values and explored moderators including vector trapping method, deployment setting (indoor/outdoor), and active ingredient (a.i.) concentration. RESULTS: A total of 49 VPSR studies containing 154 datasets met the inclusion criteria, comprising 6 trials (7 datasets) against human infection incidence, and 43 entomological studies mostly of mosquitoes (147 datasets); 73.5% tested active ingredients transfluthrin and 22.4% tested metofluthrin. Pooled estimates from transfluthrin VPSR trials indicated protective effects of 50% (95% CI 21-69%) against Plasmodium (n = 3) and 34% (95% CI 10-52%) against arboviruses (Dengue and Zika, n = 1). Evidence for Leishmania infection incidence was limited to a single trial (PE = 48%, 95% CI 26-63%). Metofluthrin showed no effect against Plasmodium (n = 1). Exposure to VPSRs was associated with substantial reductions in trapped mosquito and sand fly numbers. The comparative protection inferred from the entomological data was variably dependent on trap type: the mosquito data gave pooled mean PE values of 57-62% by human landing catches; 35-55% using Centers for Disease Control light traps (CDC-LT); and 47-88% using CDC-LT co-located with sources of CO. The wider range of pyrethroid compounds tested against Phlebotomus sand flies (n = 4) gave trap-specific PE values of 93%, 53%, and 78%, respectively. VPSR deployment in outdoor settings appeared not to be generally inferior to indoor deployment, and efficacy values tended not to differ significantly between mosquito genera. The relationship between the level of repellency (and/or lethality) and VPSR a.i. concentration is not clear, though higher concentrations (≥ 20% w/v transfluthrin or metofluthrin) appeared to be less effective. CONCLUSIONS: The collective results demonstrate that transfluthrin-based VPSRs were associated with reduced vector numbers and reduced Plasmodium infection incidence, with likely effectiveness also against arboviral and Leishmania infection incidence. However, existing evidence for reduced infection incidence is very limited despite strong entomological effects. More studies to evidence-base and strengthen conclusions are needed on many key aspects of VPSR products for programmatic and sustainable scale-up.
Molecular characterization of Sarcocystis spp. in intestines of coyotes and foxes from Pennsylvania, USA.
Gupta A, Van Why K, Brown JD … +2 more , Rosenthal BM, Dubey JP
Parasit Vectors · 2026 Jun · PMID 42316237 · Full text
BACKGROUND: Wild canids serve as definitive hosts for numerous Sarcocystis species infecting livestock and wildlife. However, species-level identification in free-ranging carnivores remains difficult, impeded by the morp...
BACKGROUND: Wild canids serve as definitive hosts for numerous Sarcocystis species infecting livestock and wildlife. However, species-level identification in free-ranging carnivores remains difficult, impeded by the morphological resemblance among the sporocysts of various parasite species. METHODS: Intestinal mucosal scrapings from 40 wild canids: red fox (Vulpes vulpes, n = 8), gray fox (Urocyon cinereoargenteus, n = 6) and coyote (Canis latrans, n = 26) in Pennsylvania, USA, sampled in 2024, were tested for Sarcocystis sporocysts. RESULTS: Sporocysts were detected microscopically in intestinal homogenates digested in Chlorox in 3/6 (50%) gray foxes, 3/8 (37.5%) red foxes and 18/26 (69.2%) coyotes. PCR amplification was successful on 8/18 (44.4%) coyotes, 0/6 Gy foxes and 2/3 (66.6%) red foxes. Multi-locus genotyping was performed for the 18S rRNA, 28S rRNA, COI and ITS1 genetic markers, supporting identification of multiple species of Sarcocystis, including Sarcocystis albifronsi-like, S. cruzi, S. gjerdei-like, S. cristata/S. wenzeli-like and an additional undescribed, ungulate-associated Sarcocystis spp. CONCLUSIONS: Phylogenetic analysis confirmed clustering with reference sequences with strong support. This study demonstrates that wild foxes and coyotes serve as definitive hosts for multiple species of Sarcocystis, including Sarcocystis cruzi, which uses cattle as intermediate hosts and imposes significant economic burdens on cattle production. Moreover, these findings demonstrate that wild canids harbor diverse Sarcocystis spp., supporting their role in environmental dissemination and potential transmission at the wildlife-livestock interface.
Risk prediction of echinococcosis in China under climate change: a One Health approach.
Diao T, Xu N, Ma N … +5 more , Chen H, Wang N, La T, Wu K, Cao B
Parasit Vectors · 2026 Jun · PMID 42310807 · Full text
BACKGROUND: Echinococcosis, a neglected zoonosis caused by Echinococcus parasites, imposes a dual burden on public health and socioeconomic development across China, with disproportionate impacts on impoverished pastoral...
BACKGROUND: Echinococcosis, a neglected zoonosis caused by Echinococcus parasites, imposes a dual burden on public health and socioeconomic development across China, with disproportionate impacts on impoverished pastoral communities. A critical barrier to targeted and effective control lies in the lack of high-resolution national risk maps and limited understanding of how climate change modulates transmission dynamics. METHODS: Here, we address these gaps by integrating multi-source epidemiological and environmental data to model and map high-resolution echinococcosis transmission risk across China. We further project its spatiotemporal evolution under four climate change scenarios (SSP126, SSP245, SSP370, SSP585) from 2040 to 2100, employing a One Health framework to assess echinococcosis transmission risk. Our model exhibits robust predictive performance, identifying elevation, annual precipitation, precipitation seasonality, isothermality, and average monthly precipitation in January as key driving factors. RESULTS: Results reveal concentrated high-risk regions in western and northern China, including Sichuan, Qinghai, Tibet, Xinjiang, and Gansu provinces, which are characterized by pastoral economies, socioeconomic underdevelopment, and constrained healthcare access. Future projections show a concerning expansion of high and very high transmission risk regions across all scenarios, with the most significant increase under the high-emission SSP585 pathway by the late twenty-first century. CONCLUSIONS: These findings clarify the current echinococcosis risk landscape and its environmental determinants while providing forward-looking, spatially explicit evidence. This work establishes a science-based foundation for optimizing resource allocation, designing adaptive prevention strategies, and enhancing health equity within a One Health framework, particularly for climate-vulnerable and resource-limited settings.
Sensitivity and specificity of HAT Bioline Abbott 2.0 and HAT Sero K-Set CORIS 2.0 for human African trypanosomiasis in the Kasai-Oriental province, Democratic Republic of the Congo: a retrospective diagnostic accuracy study.
Kayembe S, Vulu F, Mpanya A … +5 more , Kakiese E, Kalonji R, Fataki O, Kuispond NS, Ngoyi DM
Parasit Vectors · 2026 Jun · PMID 42310770 · Full text
BACKGROUND: Human African trypanosomiasis (HAT) due to Trypanosoma brucei gambiense has declined substantially in recent years, with many endemic areas now reporting very low prevalence levels as countries move toward el...
BACKGROUND: Human African trypanosomiasis (HAT) due to Trypanosoma brucei gambiense has declined substantially in recent years, with many endemic areas now reporting very low prevalence levels as countries move toward elimination. In the Democratic Republic of the Congo (DRC), rapid diagnostic tests (RDTs) are increasingly used in surveillance and elimination programs; however, their performance in low-prevalence settings remains critical. This study evaluated and compared the diagnostic accuracy of two second-generation RDTs; HAT Bioline Abbott 2.0 and HAT Sero K-Set CORIS 2.0; using trypanolysis as the reference standard. METHODS: A retrospective diagnostic accuracy study was conducted on 447 archived plasma samples (227 confirmed HAT cases and 220 controls) from a previous study in the DRC. Each sample was tested with both RDTs and trypanolysis. Sensitivity, specificity, predictive values, likelihood ratios, Cohen's kappa coefficient, and Youden's index were calculated with 95% confidence intervals. Paired comparisons were performed using McNemar's χ test, with statistical significance set at p < 0.05. RESULTS: HAT Bioline Abbott 2.0 showed a sensitivity of 85.2% (95% CI 80.4-90.0) and specificity of 72.2% (95% CI 66.4-77.9). The positive predictive value (PPV) was 73.1% (95% CI 67.5-78.6) and the negative predictive value (NPV) was 84.7% (95% CI 79.7-89.6). HAT Sero K-Set CORIS 2.0 demonstrated a sensitivity of 90.0% (95% CI 85.2-93.4) and a higher specificity of 88.2% (95% CI 83.5-91.7). The PPV was 87.1% (95% CI 82.0-90.9) and the NPV was 90.9% (95% CI 86.4-93.9). HAT Sero K-Set CORIS 2.0 showed stronger agreement with trypanolysis (κ = 0.78) and a higher Youden's index (0.78) than Abbott 2.0 (κ = 0.57; Y = 0.57). CONCLUSIONS: In this retrospective study, HAT Sero K-Set CORIS 2.0 demonstrated higher diagnostic accuracy under controlled laboratory conditions than HAT Bioline Abbott 2.0. Although both RDTs demonstrated acceptable sensitivity, neither achieved the specificity threshold (> 95%) recommended for surveillance and elimination verification in low-prevalence settings. These findings highlight the importance of optimizing specificity in serological screening tools as countries progress toward HAT elimination.
Overcoming doramectin failure: field efficacy of pour-on 5% fluralaner and an experimental 1% oral formulation for the prevention of Cochliomyia hominivorax-associated umbilical myiasis in newborn calves.
de Freitas MDB, Rodrigues DC, de Paiva PEM … +2 more , Torres S, Borges FA
Parasit Vectors · 2026 Jun · PMID 42310702 · Full text
BACKGROUND: Myiasis caused by Cochliomyia hominivorax larvae is a reemerging challenge in the Americas due to the recent reappearance of this species in areas where it had been eradicated and reports of doramectin ineffi...
BACKGROUND: Myiasis caused by Cochliomyia hominivorax larvae is a reemerging challenge in the Americas due to the recent reappearance of this species in areas where it had been eradicated and reports of doramectin inefficacy, despite its recognition as the most effective avermectin for prevention in cattle. As an alternative, 5% fluralaner administered via pour-on has shown 100% efficacy in the treatment and prevention of myiasis. Therefore, this study aimed to evaluate the efficacy of three antiparasitic treatments, namely 1% doramectin administered subcutaneously, 5% fluralaner pour-on, and 1% fluralaner administered orally, in preventing umbilical myiasis caused by C. hominivorax in newborn calves. METHODS: The study was conducted on a commercial beef cow-calf farm in Brazil. On day 0, during umbilical care, 200 newborn calves were randomly allocated to 4 groups: negative untreated control; 1% doramectin subcutaneously (200 µg/kg); 5% fluralaner pour-on (2.5 mg/kg); and 1% fluralaner orally (0.5 mg/kg, experimental formulation). All umbilical stumps were disinfected with 10% iodine tincture (10-30 s) without larvicidal compounds. Umbilical sites were evaluated on days 3, 7, and 14 for the presence of C. hominivorax larvae and lesion scores (0-3). RESULTS: The results showed marked differences among treatments in the prevention of umbilical myiasis. In the control group, myiasis occurrence was 26% (95% CI 15-39%), confirming the high field risk of the disease. Treatment with 1% doramectin did not reduce (P = 0.8153) myiasis occurrence (22%; 95% CI 12.7-35.2%), showing a relative risk reduction of only 15.4%. Pour-on 5% fluralaner reduced myiasis occurrence to 4% (95% CI 1.1-13.4%), corresponding to a preventive efficacy of 84.6%. Despite proven 100% fluralaner efficacy, maternal licking may have contributed to the removal of the pour-on product in newborn calves, potentially reducing skin residues and being associated with the occurrence of umbilical myiasis. Orally administered 1% fluralaner showed 100% preventive efficacy. Umbilical lesion scores corroborated these findings, with a predominance of score 0 in fluralaner-treated groups. CONCLUSIONS: Doramectin was ineffective in preventing umbilical myiasis in newborn calves, whereas orally administered fluralaner showed 100% preventive efficacy. Pour-on fluralaner did not achieve complete preventive efficacy, possibly due to maternal licking at the product application site in calves.
Individual and spatial heterogeneity of praziquantel efficacy against Schistosoma mansoni within the context of repeated mass drug administration.
Iacovidou MA, Reitzug F, Winter S … +8 more , Enzaru A, Asiimwe E, Nambatya J, Nakato A, Semakula M, Nabatte B, Kabatereine NB, Chami GF
Parasit Vectors · 2026 Jun · PMID 42304514 · Full text
BACKGROUND: Schistosomiasis control relies on the continued effectiveness of praziquantel (PZQ), yet individual and spatial heterogeneity in PZQ efficacy in the context of repeated mass drug administration (MDA) remains...
BACKGROUND: Schistosomiasis control relies on the continued effectiveness of praziquantel (PZQ), yet individual and spatial heterogeneity in PZQ efficacy in the context of repeated mass drug administration (MDA) remains poorly understood. This study aimed to identify individual and spatial determinants of PZQ efficacy against Schistosoma mansoni in rural Uganda. METHODS: We studied 3870 participants aged 5-90 years from 52 villages in Pakwach, Buliisa, and Mayuge districts in Uganda. Participants were recruited to the SchistoTrack cohort in January-February of 2022 and 2023. Participants received PZQ and were followed up four to five weeks later to assess cure using Kato-Katz (KK) microscopy and point-of-care circulating cathodic antigen (POC-CCA) tests. Logistic regression models were used to identify predictors of cure, defined as a 100% egg reduction rate (ERR). We explored a comprehensive set of 18 sociodemographic, biomedical, water, sanitation, and hygiene, and spatial factors. Subgroup analyses were conducted for adults (aged 18-90) versus children (aged 5-17). Spatial autocorrelation in the outcome and model residuals was assessed using join count statistics and Moran's I. RESULTS: Of 3870 clinical participants, 3704 (95.7%) received PZQ, and 3395 of these had complete clinical data. Among the 3395 treated participants, 1406 (41.4%) were infected with S. mansoni at baseline. The overall cure rate (ERR of 100%) was 76.3%, ranging from 68.9% to 85.4% across districts. Higher odds of cure were associated with older age (OR 1.34) and lower baseline infection intensity (moderate/heavy vs light OR 0.39-0.61). Greater height was associated with lower odds of cure (OR 0.99), which was driven by adults. Compared with Mayuge district, participants in Western districts had lower odds of cure (OR 0.48-0.53). In children, greater distance to water sites with snail presence was linked to higher odds of cure (OR 1.05 per 100m). Results were similar when using POC-CCA outcomes. Spatial clustering of treatment outcomes was observed by district, but no residual spatial autocorrelation remained after accounting for district effects. CONCLUSIONS: Incorporating spatial analyses, refining dose assessment, and strengthening post-MDA monitoring may help maintain PZQ effectiveness and support sustainable schistosomiasis control efforts.
Vaccination with live-attenuated Toxoplasma gondii mutants RHΔtkl1 and PruΔpp2a-c induces protective immunity in sheep.
Wu ZX, Kang Y, Hao WB … +5 more , Wang YX, Zheng Z, Huang SB, Zheng XN, Zhu XQ
Parasit Vectors · 2026 Jun · PMID 42304443 · Full text
BACKGROUND: Toxoplasma gondii is a globally distributed intracellular parasitic protozoan. It infects nearly all warm-blooded animals and causes a zoonotic disease of worldwide significance. Currently, the only commercia...
BACKGROUND: Toxoplasma gondii is a globally distributed intracellular parasitic protozoan. It infects nearly all warm-blooded animals and causes a zoonotic disease of worldwide significance. Currently, the only commercially available vaccine, Toxovax, is solely used for the prevention of Toxoplasma-induced abortion in sheep, but it has limitations such as a short shelf life and the potential of reversion to virulence. This study evaluated the safety and immune-protective efficacy of two live-attenuated strains RHΔtkl1 and PruΔpp2a-c in sheep. METHODS: Sheep were immunized via intramuscular injection in the neck with 1 × 10 tachyzoites of RHΔtkl1 or PruΔpp2a-c. Sheep were challenged orally with 5 × 10 type II Pru oocysts at 28 days post-vaccination (dpv), followed by a second challenge on day 70 with 1 × 10 type II Pru tachyzoites injected intramuscularly at 70 dpv. Safety and immuno-protection were evaluated by monitoring clinical symptoms and body temperatures, T. gondii-specific IgG antibody levels, histopathological changes, immunohistochemistry, brain cysts, parasite load, and mouse bioassay results. RESULTS: The results demonstrated that both knockout strains induced only transient fever. Following immunization and subsequent challenge with Pru oocysts, the T. gondii-specific IgG antibody levels in sheep increased rapidly and remained elevated for an extended period. Histopathological analysis indicated mild organ lesions in heart, liver and lung tissues among immunized infected sheep, whereas non-immunized infected sheep exhibited severe widespread inflammation. Immunohistochemical analysis of brain tissue revealed significantly lower values for four parameters (positive cell ratio, density, histochemistry score, immunoreactive score) in immunized groups (P < 0.01). A significant reduction in brain cysts was observed in immunized and challenged sheep (P < 0.01) compared with unimmunized and challenged sheep. The parasite burden of T. gondii in heart tissue was significantly reduced (P < 0.01). Compared with mice inoculated with sheep brain tissue from unimmunized groups challenged with T. gondii Pru oocysts and tachyzoites, mouse bioassay results showed that the mice inoculated with sheep brain tissue from groups immunized with RHΔtkl1 or PruΔpp2a-c tachyzoites and subsequently challenged with T. gondii Pru oocysts and tachyzoites exhibited a significantly lower proportion of positive genomic T. gondii DNA in the brain (P < 0.001), as well as significantly reduced levels of T. gondii-specific antibody IgG in the serum (P < 0.0001). Similarly, mice inoculated with sheep visceral tissue from the same immunized and challenged groups also showed a significantly reduced proportion of positive genomic T. gondii DNA in the brain (P < 0.0001) and significantly reduced levels of T. gondii-specific antibody IgG in the serum (P < 0.0001). CONCLUSIONS: The gene knockout strains RHΔtkl1 and PruΔpp2a-c showed a certain degree of safety in sheep, and they induced strong humoral and cellular immune responses in sheep, significantly mitigating acute infection symptoms and tissue damage. Notably, PruΔpp2a-c showed greater potential in suppressing cyst formation. Both strains are potential attenuated candidates against sheep toxoplasmosis.
ST2 blockade modulates IL-33-driven immune responses and is associated with reduced hepatic fibrosis in alveolar echinococcosis.
Shamsan E, Chuanchuan L, Haining F
Parasit Vectors · 2026 Jun · PMID 42304420 · Full text
BACKGROUND: Infection with Echinococcus multilocularis causes alveolar echinococcosis (AE), a severe parasitic disease characterised by progressive hepatic infiltration and fibrosis. Current treatment options remain limi...
BACKGROUND: Infection with Echinococcus multilocularis causes alveolar echinococcosis (AE), a severe parasitic disease characterised by progressive hepatic infiltration and fibrosis. Current treatment options remain limited, and the immune-mediated mechanisms underlying fibrosis are not fully understood. This study investigated the role of the IL-33/ST2 axis in AE-associated immunopathology and evaluated the effects of ST2 blockade in an experimental model. METHODS: A murine model of AE was established in C57BL/6 mice, which were allocated to untreated infected, anti-ST2-treated infected and uninfected control groups. Liver pathology and fibrosis were assessed using haematoxylin and eosin staining, Masson's trichrome staining and transmission electron microscopy. Immune and fibrotic markers were analysed by immunohistochemistry and immunofluorescence. In parallel, liver samples from patients with AE were examined to evaluate translational relevance. Systemic cytokine profiles were quantified to assess immune modulation. RESULTS: Analysis of human AE liver samples showed an increased expression of IL-33/ST2 and associated immune and fibrotic markers, consistent with findings in the experimental mouse model. In infected mice, ST2 blockade significantly reduced metacestode lesion size and hepatic tissue invasion. This was accompanied by reduced fibrosis, as indicated by lower expression of α-smooth muscle actin, collagen I, matrix metalloproteinase-9 and tissue inhibitor of metalloproteinases-1. Anti-ST2 treatment was also associated with reduced hepatic infiltration of CD4⁺ T cells, B cells and M2 macrophages, along with decreased systemic levels of IFN-γ, TNF-α, IL-4, IL-13, IL-17 and IL-1β. CONCLUSIONS: ST2 blockade reduced metacestode growth and was associated with attenuated hepatic inflammation and fibrosis, supporting a role for IL-33/ST2 signalling in AE progression. Given the concurrent reduction in parasite burden, further studies are needed to determine whether the anti-fibrotic effects of ST2 inhibition are independent of parasite control.
Susceptibility of Rhipicephalus microplus to fluralaner: assessment before and after implementation of a strategic control protocol in taurine cattle in a tropical region.
Chagas HDF, Gomes GW, Carvalho RA … +8 more , de Santana AM, Ascenção ACL, Souza EM, Gonzaga BCF, Ferreira LL, de Castro Rodrigues D, Lopes WDZ, Monteiro CMO
Parasit Vectors · 2026 Jun · PMID 42304416 · Full text
BACKGROUND: Fluralaner has been used in the strategic control of the Rhipicephalus microplus tick, an important ectoparasite for cattle farming. However, the effects of its application on the susceptibility profiles of t...
BACKGROUND: Fluralaner has been used in the strategic control of the Rhipicephalus microplus tick, an important ectoparasite for cattle farming. However, the effects of its application on the susceptibility profiles of these tick populations after treatment have not yet been investigated. In this study, we evaluated the effect of a strategic control protocol with fluralaner on the phenotypic susceptibility profile of a population of R. microplus before and after its implementation. METHODS: Thirty naturally infested cattle were divided into two experimental groups: T01 (control group): cattle treated with a topical (spray) formulation containing a synthetic pyrethroid and two organophosphates; T02 (strategic control): cattle treated with a formulation (pour-on) containing only fluralaner. For group T01, animals were treated when the average tick count was ≥30 to allow determination of the infestation challenge on the farm, while animals in group T02 were treated when 30% of the animals had adult ticks < 4 mm. Tick counts on animals were performed every 7 days for 266 days. Larvae monitoring in the pasture was performed every 30 days using a dragging flannel for 240 days. Larval immersion tests (LIT) and adult immersion tests (AIT) were used to assess the phenotypic susceptibility profile of ticks before and after the implementation of the strategic control protocol over a tick season in a tropical region. RESULTS: The animals in the group treated with fluralaner (T02) had lower mean tick counts (p ≤ 0.05) than those observed in the control group (T01) in 35 of the 38 evaluations during the 266 days of the study. In the pasture, the number of larvae in T02 was lower (p < 0.05) in seven of the eight evaluations. There was no increase in LC50 values for larvae and engorged females after using the strategic control protocol with fluralaner for 9 months. CONCLUSIONS: The use of the strategic control protocol with fluralaner resulted in a significant reduction in tick numbers on cattle and in pastures, and after 1 year of use, the population remained susceptible to this compound. No upward trend in LC50 values was observed after 9 months of fluralaner use.
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