Loxoscelism, caused by bites from Loxosceles spiders, is a global health concern. Control of these spiders with insecticides remains poorly understood and requires assessment at both biochemical and behavioural levels. We evaluated the ability of Loxosceles laeta to detect cypermethrin-treated surfaces and examined the effects of exposure on enzymatic activity, oxidative stress, biomolecule oxidation and locomotor behaviour. Spiders preferred untreated surfaces and increased movement speed on treated ones, indicating a repellent effect. Acetylcholinesterase activity remained unchanged, whereas antioxidant enzymes showed varied responses: catalase and glutathione reductase increased significantly, while superoxide dismutase, glutathione S-transferase and glutathione peroxidase were unaffected. Reactive oxygen species levels and lipid peroxidation did not increase, although DNA damage was detected. Exposure also reduced the distance travelled over 24 h. This study provides the first combined behavioural and biochemical analysis of L. laeta exposed to cypermethrin, offering key insights for management and toxicity assessment in medically relevant urban spiders.
Abstract Fleas (Insecta: Siphonaptera) are important vectors of zoonotic bacterial pathogens. However, the bacterial communities hosted by fleas remain poorly understood, especially regarding the interactions between nonpathogenic bacteria and pathogens, as well as the factors shaping these bacterial communities. This study aimed to explore the bacterial composition and diversity between female and male Polygenis ( Polygenis ) bohlsi bohlsi fleas collected from free‐living Thrichomys fosteri (Rodentia: Echimyidae) in the Nhecolândia region of central‐western Brazil. Here, bacterial profiling of fleas was performed using a Next‐Generation Sequencing approach targeting the V3–V4 hypervariable region of the 16S rRNA gene to assess community structure. Bacterial diversity in P. (P.) bohlsi bohlsi fleas varied by sex, as indicated by significant differences in alpha diversity, while beta diversity showed a trend toward separation between sexes. Pseudomonadota was the predominant phylum in the flea microbiome. Ten bacterial genera showed differentially abundance between male and female fleas, including Bartonella spp., which was detected exclusively in males, and Wolbachia spp., which was more abundant in females than in males. Phylogenetic analysis positioned Bartonella gltA sequences detected in two fleas within the same clade as Bartonella harrusi . While the Wolbachia wsp and 16S rRNA sequences detected in P. (P.) bohlsi bohlsi grouped within the supergroups S (associated with pseudoscorpions), gatB sequences grouped with V (cat flea‐related). These findings suggest sex‐associated differences in the microbiome of P. (P.) bohlsi bohlsi fleas and highlight the need for further investigation into the potential role of Wolbachia spp. in shaping flea‐associated microbial communities and their interactions with Bartonella spp.
Fleas (Insecta: Siphonaptera) are important vectors of zoonotic bacterial pathogens. However, the bacterial communities hosted by fleas remain poorly understood, especially regarding the interactions between nonpathogenic bacteria and pathogens, as well as the factors shaping these bacterial communities. This study aimed to explore the bacterial composition and diversity between female and male Polygenis (Polygenis) bohlsi bohlsi fleas collected from free-living Thrichomys fosteri (Rodentia: Echimyidae) in the Nhecolândia region of central-western Brazil. Here, bacterial profiling of fleas was performed using a Next-Generation Sequencing approach targeting the V3-V4 hypervariable region of the 16S rRNA gene to assess community structure. Bacterial diversity in P. (P.) bohlsi bohlsi fleas varied by sex, as indicated by significant differences in alpha diversity, while beta diversity showed a trend toward separation between sexes. Pseudomonadota was the predominant phylum in the flea microbiome. Ten bacterial genera showed differentially abundance between male and female fleas, including Bartonella spp., which was detected exclusively in males, and Wolbachia spp., which was more abundant in females than in males. Phylogenetic analysis positioned Bartonella gltA sequences detected in two fleas within the same clade as Bartonella harrusi. While the Wolbachia wsp and 16S rRNA sequences detected in P. (P.) bohlsi bohlsi grouped within the supergroups S (associated with pseudoscorpions), gatB sequences grouped with V (cat flea-related). These findings suggest sex-associated differences in the microbiome of P. (P.) bohlsi bohlsi fleas and highlight the need for further investigation into the potential role of Wolbachia spp. in shaping flea-associated microbial communities and their interactions with Bartonella spp.
Urban ants may act as mechanical carriers of pathogenic microorganisms in hospitals, potentially posing a risk to public health. To support infection control strategies, we investigated the occurrence of ants associated with clinically relevant microorganisms in a public hospital in Maceió, Alagoas, Brazil. Ants were collected from 17 hospital sectors, and the most prevalent species were Tapinoma melanocephalum and Dorymyrmex brunneus. Microbiological analyses revealed bacterial isolates associated with ants in 10 hospital areas, including emergency wards. A total of 18 bacterial isolates were identified across eight genera, including clinically relevant bacteria such as Escherichia coli, Pluralibacter gergoviae, Citrobacter koseri, Acinetobacter sp. and Pseudomonas sp. Several isolates exhibited resistance to multiple antibiotics, including carbapenems. These findings highlight the potential epidemiological relevance of ants associated with pathogenic and antibiotic-resistant bacteria in hospital environments, emphasising the need for improved pest management and environmental control measures.
Tick-borne diseases (TBDs), such as anaplasmosis and babesiosis, pose significant challenges to dairy farming in subtropical regions, where balancing tick control with immune development is essential to maintaining herd health. This study evaluated the immune responses of calves raised under confined and traditional systems in Ecuador. Serum samples from 124 cows and their calves were analysed using ELISA assays to detect Anaplasma marginale antibodies and Babesia bovis antigens. The results showed a significantly higher seroprevalence of A. marginale antibodies in calves reared under traditional systems (98 %) compared to those raised under confinement (32 %) (p < 0.01), suggesting that early exposure to infected ticks enhances immune response development. In contrast, antigen levels for B. bovis were low overall (1 % Ag-prevalence), suggesting limited pathogen circulation, although the Ag-prevalence was slightly higher in traditional systems (2 %). In confined systems, maternal antibody transfer appeared to play a more prominent role, whereas calves in traditional systems developed a more active, independent immunity. These findings highlight the importance of calf-rearing strategies that incorporate controlled tick exposure alongside targeted management practices to enhance herd resilience and mitigate economic losses. A balanced approach considering endemic stability could improve long-term protection against TBDs in subtropical dairy farming systems.
In the era of globalization, the emergence and re-emergence of vector-borne diseases are a public health concern. Aedes albopictus was introduced in the city of Limassol, Cyprus, in 2022. Herein, we present information on the seasonal dynamics of Ae. albopictus from 2022 to 2024 by actively monitoring the locations where Ae. albopictus was first reported by citizens. Our two-year field trapping scheme shows that despite any control interventions, Ae. albopictus continues to spread. Female Ae. albopictus abundance is influenced by maximum temperature, daylight duration and location, while sex ratio (male-to-female) depends on temperature, wind speed and location. Aedes albopictus shows strong seasonal activity, peaking during the summer-autumn period (June to October/November), within activity during winter and early spring months (February to mid-April 2023 and February 2024). This is the first study on the seasonal dynamics of Ae. albopictus for Cyprus through which we would like to underscore the need for tailored mosquito management strategies, along with active citizen participation in monitoring and control interventions.
The Australian carrion-breeding species of the blowfly subfamily Calliphorinae, collectively placed in the Calliphora stygia- and ochracea-group sensu Johnston, Szpila, et al., 2025, play crucial roles in forensic science and agriculture, serving as key indicators of time since death of corpses and facultative agents of myiasis in livestock. Additionally, carrion-breeding blowflies have growing relevance in biomedical research due to their application in maggot debridement therapy and their emerging potential as sources of novel therapeutic compounds. Despite this recognised importance, the Australian representatives of these species groups remain poorly understood, with many aspects of their taxonomy and species boundaries unclear. This, in turn, complicates their reliable identification, hindering their use in applied contexts. Here, an integrative revision of the C. stygia- and ochracea-groups is presented, treating 17 species along with the taxonomically unplaced Calliphora lordhowensis, using morphology and mitochondrial DNA to elucidate species boundaries. We provide a new diagnostic key to support the identification of these groups and provide verified COX1 sequences for most species. We utilise molecular and morphological data to support the synonymisation of Calliphora albifrontalis as a junior synonym of C. stygia, which has implications for the use of this species in forensic and medical applications.
Global invasions by the mosquito Aedes albopictus pose serious threats to biodiversity and public health due to its capacity to vector multiple emerging infectious diseases. As a highly invasive species, its success is closely linked to environmental conditions during its complex life cycle. In this study, we investigated how compositionally distinct environmental microbiomes influence A. albopictus development, physiology and starvation resistance. Larvae were reared in mesocosms containing water from three sources-laboratory, plastic buckets and bromeliad tanks-each filtered at three levels (30-50 μm, 10 μm and 0.1 μm) to manipulate microbial diversity. We found that microbial community composition significantly affected larval development time and pupation success. Larvae reared in water with reduced microbial diversity developed faster and had higher pupation success than those exposed to more complex communities. Although lipid concentrations and time to adult eclosion were unaffected across habitat types, adult survival under starvation conditions varied significantly by microbial exposure and sex. Females from low-diversity habitat types exhibited the highest survival, suggesting early-life microbial environments influence adult fitness traits critical to invasion success. These results highlight the ecological importance of environmental microbiomes in shaping mosquito life history and suggest that microbial diversity in larval habitat types may influence the establishment and spread of A. albopictus in novel environments.
Abstract This study aimed to detect the DNA of Anaplasma spp., Ehrlichia spp., Borrelia spp. and protozoa of the order Piroplasmida in blood samples from 73 coatis captured at three sites in the Iguaçu National Park. PCR assays revealed a high prevalence of Anaplasma spp., with 47.9% (35/73) of animals testing positive for the 16S rRNA and 23S rRNA genes. None of the samples tested positive for Borrelia spp., Ehrlichia spp. or protozoa of the order Piroplasmida. Sequencing analyses indicated that all positive samples were genetically identical and closely related to Anaplasma platys and lineages previously described in cattle and ticks. Phylogenetic analyses based on multiple loci revealed distinct clades, supporting the circulation of a unique Anaplasma variant in coatis. Comparisons with tick‐derived sequences showed genetic divergence, suggesting distinct strains infecting hosts and vectors. These findings provide novel insights into the epidemiology of haemoparasites in wildlife and highlight the role of coatis as potential reservoirs of diverse Anaplasma lineages in the Atlantic Forest.
Bed bugs are blood-sucking ectoparasites of humans and animals worldwide. However, limited data exist for Indonesia. This study aimed to identify bed bug species and its associated bacteria in four cities in Indonesia: Bogor Regency, East Jakarta, Cianjur and Bandung. Samples were collected only from houses with the owners' permission. Morphological identification only characterised one bed bug species, Cimex hemipterus. One house in Cianjur had the highest count of bed bugs, significantly reducing the homeowner's quality of life. Both non-pathogenic and suspected pathogenic bacteria, including Bradyrhizobium sp., Afipia sp. and Pseudomonas sp., were detected.
The genus Cavernicola belongs to the subfamily Triatominae, which includes insect vectors of Chagas disease. This study reports the occurrence of Cavernicola pilosa Barber infected with Trypanosoma cruzi marinkellei Baker et al. (Kinetoplastida: Trypanosomatidae) in the state of Acre, Brazil. The triatomine bug was collected inside a house by a resident of Cruzeiro do Sul, Acre. Specimen identification was based on the morphological characters described by Galvão (2014). Trypanosomatid identification was performed through DNA extraction from the abdominal contents of the specimen, followed by fluorescent fragment length barcoding and phylogenetic analyses using the V7-V8 region of the SSU rRNA and the gGAPDH gene. The insect was identified as a male Cavernicola pilosa infected with Trypanosoma cruzi marinkellei. This record increases the known number of triatomine species in the state of Acre from 11 to 12 and the number of genera from four to five. Furthermore, it represents the first documented occurrence of a Triatominae species infected with T. c. marinkellei in Acre, highlighting the need for further studies to elucidate the distribution, ecology and vectorial potential of C. pilosa in the region.
Mosquitoes of the genus Culex are important vectors of St. Louis encephalitis (SLEV) and West Nile (WNV) viruses, and their host-feeding patterns strongly influence transmission dynamics by shaping contact rates between avian and mammalian hosts. In the United States, several Culex species exhibit seasonal shifts in host use, feeding primarily on birds during summer and increasing mammalian feeding in autumn. This shift coincides with seasonal peaks in SLEV and WNV incidence, suggesting that changes in mosquito feeding behaviour may trigger viral spillover to mammals. However, no experimental study has evaluated whether such seasonal patterns occur in South American populations. In this study, it was tested whether an Argentinean population of Culex quinquefasciatus shows seasonal variation in feeding preference under controlled laboratory conditions. Starved females were simultaneously offered a chick (Gallus gallus) and mouse (Mus musculus) in dual-choice assays conducted under summer and autumn conditions, both representing a combination of simulated temperature and photoperiod regimes. Blood-meal sources were determined using multiplex polymerase chain reaction (PCR), and feeding proportions were analysed using a Bayesian multinomial logistic regression. Mosquitoes fed on both hosts in both seasons with a high proportion of mixed blood meals, with no consistent evidence of a seasonal host shift. Substantial variation among replicates indicated high intra-population heterogeneity. Overall, Cx. quinquefasciatus exhibited a generalist and plastic feeding strategy rather than a defined seasonal pattern. Although no seasonal shift was detected, the generalist behaviour supports its potential role as a bridge vector of arboviruses in South America.
Malaria is caused by the Plasmodium parasites transmitted by Anopheles mosquitoes. After ingestion by a mosquito vector, malaria parasite gametocytes differentiate into gametes and undergo fertilization in the midgut to form zygotes. The zygotes develop into ookinetes that traverse the midgut wall and form oocysts, within which sporozoites are produced. Our previous study characterized the transcriptome profiles of Plasmodium vivax and Anopheles dirus at the ookinete and oocyst stages. This study focused on the transcriptome analysis of An. dirus and P. vivax at 14-day post-infection, corresponding to the sporozoite stage. Transcripts corresponding to 1706 P. vivax genes were identified. Comparative transcriptomic analysis between P. vivax-infected and uninfected An. dirus revealed 112 upregulated, 599 downregulated and 8420 stably expressed genes. PvETRAMP10.3 and PvSS10 were highly expressed during the P. vivax sporozoite stage, suggesting potential roles in parasite infection competency. Upregulated An. dirus genes were associated with transcription processes, including DNA-dependent RNA polymerase activity, cholesterol transport and host defence mechanisms via C-type lectin domain-containing protein. In contrast, several genes associated with the innate immunity, host development and cellular homeostasis in An. dirus were downregulated. Notably, vitellogenin and regucalcin were drastically downregulated, suggesting potential roles in parasite-mosquito interactions during sporozoite infection. The expression patterns of selected An. dirus and P. vivax genes from RNA-Seq analysis were consistent with those determined by RT-qPCR, confirming the reliability of the transcriptomic data.
Chagas disease remains a public health concern in rural and peri-urban areas of Mexico, where environmental and sociocultural conditions favour the presence of triatomines and the transmission of Trypanosoma cruzi Chagas (Kinetoplastida: Trypanosomatidae). We conducted a cross-sectional survey in two localities of Zacatepec, Morelos, to document peridomestic infestation by Triatoma pallidipennis Stål (Hemiptera: Reduviidae), its natural infection with T. cruzi, and community knowledge, attitudes and practices. A total of 46 triatomines were collected, all identified as T. pallidipennis, with T. cruzi detected in all specimens. Overall infestation was 25.3% and colonization index was 47.8%, with a density of 50.5 triatomines per 100 dwellings whose peridomestic areas were inspected and an average of 2.0 triatomines per infested dwelling. Triatoma pallidipennis was found in peridomestic habitats associated with accumulation of materials, domestic animals and surrounding vegetation. Survey results indicated general awareness of the disease but limited knowledge of symptoms and preventive measures, with control practices mainly based on insecticide use. These findings provide local evidence of peridomestic vector presence and T. cruzi infection in Zacatepec, Morelos, Mexico and support the need to strengthen surveillance and community-based prevention strategies.
In Rio Grande do Norte, Brazil, updated studies on synanthropic triatomines are needed to elucidate population dynamics and identify high-risk areas for parasite transmission. This study evaluated active searching, vector control, and entomological indicator activities, as well as the distribution of triatomine species captured in domestic environments across different mesoregions of the state from 2005 to 2022. Secondary data on triatomine captures in domiciliary units (DUs) from municipalities in the Agreste, Central, and West mesoregions were analysed. These data were provided by the Rio Grande do Norte State Secretariat for Public Health. Entomological surveillance activities were implemented discontinuously throughout the period, ranging from 2 to 12 years. No entomological surveillance activities were performed in the East mesoregion, nor in 46.5% (20/43) of municipalities in the Agreste, 18.9% (7/37) in the Central, and 11.3% (7/62) in the West mesoregions. Triatomine presence was recorded in most municipalities where entomological surveillance activities were conducted, and the number of surveyed and positive DUs was higher in the Central and West mesoregions. The overall infestation index was highest in the West and Central mesoregions municipalities. Additionally, the natural infection index by Trypanosoma cruzi (Trypanosomatida: Trypanosomatidae) was elevated in all three mesoregions. Triatoma brasiliensis and Triatoma pseudomaculata were the most frequently captured species. The West mesoregion exhibited the highest number of specimens captured and the greatest diversity of triatomines. Discontinuities in entomological surveillance and vector control, combined with insufficient systematic monitoring and limited integration between the community and health services, likely contributed to persistent infestation and colonization of anthropic environments by triatomines. Furthermore, the constant presence of native triatomine species infected with T. cruzi in dwellings underscores the ongoing risk of parasite transmission to humans and domestic animals.
Hyalomma marginatum Koch, 1844, is a competent vector of the Crimean-Congo hemorrhagic fever virus (CCHFV) and other zoonotic pathogens, typically associated with warmer Mediterranean environments. Between 2019 and 2024, as part of the activities of the Galician Vector Surveillance Network (ReGaViVec), a passive surveillance program was carried out in the northwest of the Iberian Peninsula, involving regional Healthcare centers, livestock farms, equestrian facilities, Wildlife Rescue Centers, Veterinary clinics and private individuals. A total of 63 adult specimens were morphologically identified as H. marginatum, collected from humans (60.3%), free-range ungulates (35%), dogs (3.2%) and the environment (1.6%). The annual distribution ranged from 1.6% of the total in 2019 to 57.1% in 2024. Seasonal activity peaked in spring (54%), declined slightly in summer (44%) and was absent in winter. Most specimens (82.5%) came from areas under a Mediterranean climate and warm summers, and 66% were collected at locations less than 15 km from where the first specimen was found. Human infestations were primarily associated with agricultural activities (47.6%) and recreational walking in wooded areas (42.9%). Regarding human anatomical distribution, the most frequent attachment sites were the trunk (34.2%) and the lower extremities (21.1%). The continuing detection of H. marginatum ticks in the study area, along with changes in their spatial distribution over a 6-year period, highlights the need to implement surveillance protocols based on a 'One Health' approach to monitor the potential establishment of this vector in NW Spain, as well as the risk of some pathogens associated with it.
Understanding mosquito (Diptera: Culicidae) feeding behaviour is essential for assessing arbovirus transmission risk. Culex mosquitoes are key vectors, yet their host-feeding patterns in urban areas of South America remain understudied. This study examined the blood-feeding patterns of four Culex species in Córdoba, Argentina, emphasizing overall trends, seasonality and host preferences. Mosquitoes were collected during spring, summer and autumn across four urban sites over a 2-year period (2017-2018). Blood meals were identified through molecular analysis. Culex dolosus fed exclusively on birds, while Cx. interfor Dyar, Cx. saltanensis Dyar and Cx. quinquefasciatus Say fed on both birds and mammals. Culex quinquefasciatus accounted for most identified blood meals (n = 219), with 83% derived from birds and 17% from mammals. The most frequently detected local avian hosts were Zenaida auriculata (24.5%) and Passer domesticus (10%), while the most common mammalian hosts were Canis lupus familiaris (14.5%) and Homo sapiens (13.6%). Bird-derived blood meals predominated in all seasons. Forage ratio estimates indicated that Cx. quinquefasciatus exhibited a preference for P. domesticus, Agelaioides badius and C. lupus familiaris. These results highlight key vertebrate hosts potentially involved in local transmission cycles, with Z. auriculata and P. domesticus emerging as important nodes for arbovirus maintenance in urban Córdoba.
Dogs are common companion animals, often infested by fleas that can transmit zoonotic pathogens in rural tropical areas. In Colombia, studies on flea-borne agents in dogs are limited. Understanding the presence of these ectoparasites and associated microorganisms is crucial. To assess flea infestation and detect and identify Rickettsia and Bartonella spp. in fleas collected from dogs in Cundinamarca, Colombia. Between 2019 and 2020, fleas were collected from rural domestic dogs in 24 municipalities of western Cundinamarca. Fleas were morphologically identified and pooled for DNA extraction. Molecular screening of Rickettsia and Bartonella spp. was performed by qPCR. Positive samples underwent further characterization by conventional PCR. Rickettsia was additionally analyzed using RFLP, while Bartonella was evaluated through phylogenetic analysis. Of the 116 dogs examined across 24 municipalities, 39.7% were infested with fleas. A total of 138 fleas were collected and grouped into 46 pools, with Ctenocephalides felis felis identified in 94% of them. Rickettsia was detected in 83% of pools, with Rickettsia asembonensis and Rickettsia felis identified in most positive samples. Bartonella was found in 28% of pools; however, sequencing success was limited, and no species-level identification could be achieved. This study documents flea infestation in domestic dogs in Cundinamarca, predominantly by C. felis felis. High detection of R. asembonensis and presence of R. felis confirm widespread rickettsial circulation in fleas. Bartonella was detected less frequently, but species-level identification was not achieved.
Reptile-associated (REP) borreliae represent a distinct monophyletic lineage of spirochetes transmitted by hard ticks. These organisms have been reported in several regions worldwide, including South Africa, but had not been reported in ticks collected in Zambia until now. In this study, we screened for Borrelia spp. in Amblyomma marmoreum ticks collected from Leopard tortoises (Stigmochelys pardalis) in Southern Province, Zambia. Of the 87 tick DNA samples analysed, 74 (85.1%) were positive by Borrelia-specific real-time PCR. Subsequent BLASTn and phylogenetic analyses of flaB and 16S rDNA sequences confirmed that the detected Borrelia spp. belong to REP borreliae and are closely related to Borrelia sp. previously reported from South Africa. This study represents the first molecular confirmation of REP borreliae in A. marmoreum ticks collected in Zambia and expands the known distribution of these spirochetes. The findings underscore the need for further investigations on their ecology and epidemiology to better understand the public and animal health relevance and transmission dynamics of REP borreliae in reptile-associated tick populations.
Sand flies are arthropod vectors responsible for transmitting Leishmania parasites to humans. Among them, Phlebotomus (P.) major, P. syriacus and P. neglectus are closely related sister species that play an important role in disease transmission in Türkiye. This study aimed to statistically analyse the morphological measurements of these three species and to identify reliable diagnostic characters. Seven morphometric traits were measured in both female and male specimens. Statistical analyses, including analysis of variance (ANOVA), discriminant function analysis (DFA) and principal component analysis (PCA), were performed to determine significant variables contributing to species differentiation. A total of 1729 sand flies were collected, comprising P. tobbi (44.58%), P. papatasi (21.26%), P. similis (20.30%), P. neglectus (8.50%), P. major (2.88%), P. syriacus (2.19%) and Sergentomyia (S.) fallax (0.27%). The female-to-male ratio was 1.42. ANOVA revealed significant interspecific differences (p < 0.001) in antennal, pharyngeal and genital characters. In females, P. neglectus exhibited shorter antennal segments A3 and A4 + A5, P. syriacus had the shortest pharynx (PHX), and P. major showed the longest epipharynx (EPI). In males, P. major had the longest coxite (CX), whereas P. neglectus displayed the shortest second style segment (S2) (p < 0.05). DFA confirmed clear species separation, with antennal and pharyngeal traits primarily driving differentiation in females, and genital characters being most informative in males. PCA explained 78.37% and 90.24% of the total morphometric variation in females and males, respectively, highlighting sex-specific patterns of morphological variation. Overall, these statistically supported morphometric differences provide robust diagnostic features that can complement molecular approaches, improving species identification and enhancing taxonomic resolution in sand fly vector studies.
