Triatomine species (kissing bugs) infected with Trypanosoma cruzi are found across the southern United States. The northern limits of Trypanosoma cruzi infected kissing bugs are less understood. The objective of this work was to describe the locations of kissing bugs from Illinois and Missouri based on historical records, submissions to Texas A&M University's (TAMU) Kissing Bug Community Science Program and the Centers for Disease Control and Prevention (CDC), and records from online platforms (iNaturalist, BugGuide, and GBIF) up to and including 2022. A total of 228 records were discovered, including 186 from historical or observation platforms and 42 specimens submitted to TAMU or CDC. Species included Triatoma sanguisuga (221 total records, 9 nymphs) and Triatoma lecticularia (7 records). Notably, nearly all (24/26) records submitted to TAMU were collected indoors. Twelve of the 30 (40%) specimens tested were positive for the presence of T. cruzi, including parasite discrete taxonomic units TcI and TcIV. One triatomine sample had been found in a bed feeding on the submitter; this bug was positive for T. cruzi and had evidence of human blood in its gut. Records suggest a ubiquitous distribution in Missouri and potentially to the northernmost border in Illinois. Further investigations into triatomine distribution and infection status are needed within states assumed to be northern limits in order to create public health and veterinary health messaging and baseline distributional maps from which to measure future range shifts in relation to a changing climate.

Triatoma sanguisuga (Leconte) is one of the most widely distributed kissing bugs in the United States, associated with an extensive zoonotic circulation of Trypanosoma cruzi, the agent of Chagas disease, in a large part of the country. However, the actual risk for human infection in the United States is poorly understood. Here, we further assessed the ecology of T. sanguisuga bugs collected in residents' houses in Illinois and Louisiana, using a metagenomic approach to identify their blood-feeding sources, T. cruzi parasites and gut microbiota. Blood meal analysis revealed feeding on domestic animals (dogs, cats, pigs, goats, and turkeys), synanthropic species (raccoons, opossums, and squirrels), as well as the more sylvatic white-tail deer. Human blood was identified in 11/14 (78%) of bugs, highlighting a frequent vector–human contact. The infection rate with T. cruzi was 53% (8/15), and most infected bugs (6/8) had fed on humans. A total of 41 bacterial families were identified, with significant differences in microbiota alpha and beta diversity between bugs from Louisiana and Illinois. However, predicted metabolic functions remained highly conserved, suggesting important constraints to fulfill their role in bug biology. These results confirmed a significant risk for vector-borne transmission of T. cruzi to humans in Louisiana and Illinois, which warrants more active screening for human infections. Also, while there is broad plasticity in the bacterial composition of T. sanguisuga microbiota, there are strong constraints to preserve metabolic profile and function, making it a good target for novel vector control strategies.

Graphical Abstract

Chagas disease is an infectious disease of human and animal health concern, with 6–8 million chronic human infections and over 50,000 deaths throughout the Americas annually. Hematophagous insects of the subfamily Triatominae, also called kissing bugs, vector the protozoan parasite, Trypanosoma cruzi Chagas (Trypanosomatida: Trypanosomatidae), that causes Chagas disease. Despite the large human health burden, Chagas disease is a neglected tropical disease with inadequate funding for research and preventive practices. Given the resource-poor environment of most agencies trying to protect public health, it is critical to consider all control options for reducing vector populations and the risk of human exposure to T. cruzi to identify the most appropriate tools for each context. While numerous triatomine control methods exist, the literature lacks a compilation of the strategies used, a critical examination of their efficiency, and a particular focus on triatomine control in the United States compared to elsewhere in the Americas. Here, we present a review of the literature to assess historical intervention strategies of existing and developing triatomine control methods. For each method, we discuss progress in the field, future research to further advance the method, and limitations. While we found that pyrethroid insecticide is still the most commonly used method of triatomine and Chagas disease control, we suggest that complementing these techniques with alternative control methods in development will help to achieve Chagas disease reduction goals.

Population genetic structure of arthropod disease vectors provides important information on vector movement and climate or other environmental variables that influence their distribution.This information is critical for data-driven vector control. In the first comprehensive study of the genetic structure of T. dimidiata s.l. (Latreille, 1811) we focus on an area of active transmission designated as a top priority for control.We examined a high number of specimens across a broad geographic area along the border of Guatemala and El Salvador including multiple spatial scales using a high number of genome-wide markers. Measuring admixture, pairwise genetic differentiation, and relatedness, we estimated the specimens represented three genetic clusters. We found evidence of movement (migration/gene flow) across all spatial scales with more admixture among locations in El Salvador than in Guatemala. Although there was significant isolation by distance, the 2 close villages in Guatemala showed either the most or least genetic variation indicating an additional role of environmental variables. Further, we found that social factors may be influencing the genetic structure. We demonstrated the power of genomic studies with a large number of specimens across a broad geographic area.The results suggest that for effective vector control movement must be considered on multiple spatial scales along with its contributing factors.

Graphical Abstract

La estructura genética de las poblaciones de vectores de enfermedades artrópodos, proporciona información importante sobre sus patrones de migración y del clima u otras variables ambientales que influyen en su distribución. Esta información es fundamental para el control de vectores basado en datos científicos. En este primer estudio exhaustivo de la estructura genética de T. dimidiata s.l. (Latreille, 1811) se examinó un área de transmisión activa de alta prioridad para su control. Se midió una gran cantidad de especímenes en una amplia área geográfica a lo largo de la frontera de Guatemala y El Salvador, incluyendo múltiples escalas espaciales y una gran cantidad de marcadores en todo el genoma. Utilizando medidas de mezcla y diferenciación genética y de relación genética por pares, se estimó que los especímenes representaban tres grupos genéticos, con migración/flujo de genes en todas las escalas espaciales. Sin embargo, hubo más mezcla entre ubicaciones en El Salvador que en Guatemala. A pesar de que se encontró aislamiento genético significativo debido a la distancia, el hecho de que dos pueblos cercanos en Guatemala mostraron la mayor o la menor variación genética indicó un papel adicional de las variables ambientales. Además, encontramos que los factores sociales pueden estar influyendo en la estructura genética. Se demostró el poder de los estudios genómicos con una gran cantidad de especímenes en una amplia área geográfica. Los resultados sugieren que para un control eficaz de los vectores, el migración/flujo de genes debe considerarse en múltiples escalas espaciales junto con sus factores contribuyentes.

Surveillance of triatomines or kissing bugs (Hemiptera: Reduviidae: Triatominae), the insect vectors of Trypanosoma cruzi, a Chagas disease agent, is hindered by the lack of an effective trap.To develop a kissing bug trap, we made iterative improvements over 3 years on a basic design resulting in 7 trap prototypes deployed across field sites in Texas, United States and Northern Mexico, yielding the capture of 325 triatomines of 4 species (Triatoma gerstaeckeri [Stål], T. sanguisuga [LeConte], T. neotomae [Neiva], and T. rubida [Uhler]). We began in 2019 with vertical transparent tarpaulin panel traps illuminated with artificial light powered by AC current, which were successful in autonomous trapping of flying triatomines, but were expensive, labor-intensive, and fragile. In 2020, we switched to white LED lights powered by a solar cell. We tested a scaled-down version of the vertical panel traps, a commercial cross-vane trap, and a multiple-funnel trap. The multiple-funnel traps captured 2.6× more kissing bugs per trap-day than cross-vane traps and approached the performance of the vertical panel traps in number of triatomines captured, number of triatomines per trap-day and triatomines per arthropod bycatch. Multiple-funnel traps required the least labor, were more durable, and had the highest triatomines per day per cost. Propylene glycol in the collection cups effectively preserved captured triatomines allowing for molecular detection of T. cruzi. The trapping experiments established dispersal patterns for the captured species. We conclude that multiple-funnel traps with solar-powered LED lights should be considered for adoption as surveillance and potentially mass-trapping management tools for triatomines.

Chagas disease, caused by the protozoan Trypanosoma cruzi, is a zoonosis primarily found in rural areas of Latin America. It is considered a neglected tropical disease, and Triatoma dimidiata is the main vector of the parasite in Central America. Despite efforts, Chagas disease continues to be a public health concern, and vector control remains a primary tool to reduce transmission. In this study, we tested the hypothesis that highly abundant bacteria in the gut of T. dimidiata inhibit the growth of T. cruzi. To achieve this, bacterial diversity in the gut of T. dimidiata specimens from Costa Rica was characterized by metabarcoding of the 16S rRNA, microbial isolation was performed, and the effect of freeze-dried supernatants of the isolates on T. cruzi was investigated. Metabarcoding showed that the most abundant genera in the gut were Corynebacterium, Tsukamurella, Brevibacterium, and Staphylococcus. Barcoding and sequences comparison confirmed that 8 of the 30 most abundant amplicon sequence variants (ASVs) were isolated, and 2 of them showed an inhibitory effect on the growth of T. cruzi epimastigotes. These bacteria correspond to isolates of Tsukamurella and Brevibacterium, which were respectively the second and sixth most abundant ASVs in the gut of T. dimidiata. Notably, only the isolate of Brevibacterium showed a significant difference in growth inhibition against epimastigotes of both T. cruzi strains tested. These findings suggest that the gut microbiota of T. dimidiata may play an active role in modulating parasite development.

Graphical Abstract

Triatomines (Hemiptera: Reduviidae) are hematophagous insects that transmit Trypanosoma cruzi, the etiological agent for Chagas disease, to humans and other mammals. As medically important vectors, species such as Rhodnius prolixus (Hemiptera: Reduviidae) have long been used as a model organism for physiological studies. Laboratory rearing of triatomines is needed to support vector and parasite research. Many environmental conditions, such as suitable housing containers, light source and duration, temperature, humidity, and density, must be addressed when adapting triatomines from a natural habitat for artificial rearing to create conditions for optimal growth and survival. Food source is also an important factor, as triatomines are considered the obligate blood feeders. Parasites and pathogens present risks not only for triatomines but also for the laboratorians handling them. Equipping an insectary space should apply best practices to ensure community, personnel, and insect health. Various triatomine colonies have been maintained in the Centers for Disease Control and Prevention (CDC) Entomology Branch insectary for over 25 years and have more recently been made available to the research community through the Biodefense and Emerging Infections Research Resources Repository (BEI Resources). The CDC Rhodnius prolixus genome has been characterized and thus represents an opportunity for continued model organism research. In addition to fulfilling requests for live triatomines, inquiries are received for support in establishing new and troubleshooting existing laboratory colonies. To accompany the extensive MR4 manual, Methods in Anopheles Research, procedures for triatomine husbandry have been developed and are shared here to address the aforementioned topics.

The landing patterns of blood-sucking females (Diptera: Tabanidae) are largely influenced by their visual perceptions. When attacking humans, the shape of different body parts and overall brightness of the body could be the factors determining the place of blood-sucking.The visual attractiveness of the human body for tabanids was investigated through a black and a white mannequin in the Danube floodplain, Slovakia. The mannequins were covered by glue once a week. On both of the mannequins, 332 horse flies were stuck. The trapped horse flies on the mannequins belong to the genera Tabanus Linnaeus, 1758, Hybomitra Enderlein, 1922, Chrysops Meigen, 1803, Haematopota Linnaeus, 1758 and Atylotus (Linnaeus, 1767). Based on the trapped tabanids, the black mannequin is 6.06 times more attractive than the white one. The most tabanid carcasses were found on the lower limbs (56.32%) and the least occurred on the head (2.1%), the difference in their occurrence between the lower limbs and head of both mannequins was significant (P < 0.001). A similar significant difference was observed on certain parts of both mannequins on the taxonomical level of the genera Tabanus, Hybomitra, and Atylotus, the carcasses of which aggregated mostly on the lower limbs, rather than on the upper limbs and head.

Graphical Abstract

The visual attractiveness of the human body of tabanids was investigated through black and white mannequins covered by glue. Based on the trapped tabanids, the black mannequin is 6.06 times more attractive than the white one.The most attractive parts of the human body are the lower limbs, and the least attractive area is the head. 54 × 30 mm (600 × 600 DPI)

Forensic entomology plays a crucial role in estimating the minimum postmortem interval through the study of insect larvae found at crime scenes. The precision of this estimation relies on various biotic and abiotic elements that simultaneously influence insect growth and development, encompassing factors such as temperature, humidity, photoperiod, diet, and the existence of xenobiotics in decomposing tissues. Despite numerous studies on the influence of these factors, including the impact of xenobiotics, there are currently no robust tools available for making corrections to this estimation considering concurrently all variables. In an attempt to propose an exploratory and descriptive statistical model to analyze the simultaneous effect and interaction of different variables on larval growth, this study aimed to compare the effect of malathion on the growth of Megaselia scalaris (Loew, 1866) (Diptera: Phoridae) raised in malathion-spiked porcine muscle, under controlled and uncontrolled temperature and humidity conditions (environmental conditions). Larvae were also reared using various growth media. A split-plot design that combined crossed and nested factors was employed; 2 linear mixed models were developed to assess the relationships between the variables. The model provides valuable insights into the complex interactions among xenobiotics, growth media, and environmental conditions in the size and development of M. scalaris.

A new sand fly species, Trichophoromyia jariensis n. sp. Cavalcante, Rodrigues, & Galati, from the state of Amapá, Brazil, is described based on both male and female morphology and cytochrome c oxidase subunit I DNA barcodes.The DNA barcoding analysis clearly associated males and females of this new species.

Malaria was once endemic in the United States prior to its elimination in 1951. However, due to consistent introductions of travel-associated malaria cases and the presence of several native Anopheles species (Diptera: Culicidae) that are competent vectors of malaria, the potential for local (autochthonous) malaria transmission remains a persistent threat in the United States. While several intermittent cases of local malaria transmission have occurred in the United States in the decades since elimination, the emergence of autochthonous transmission in 4 states in 2023 demonstrates the continued risk for future outbreaks. Moreover, these recent examples also highlight significant gaps in current mosquito surveillance efforts that have predominantly focused on threats of arboviral disease, such that our understanding of Anopheles distributions relies only on historical records and offers limited insight into the ecological factors that influence their abundance. Herein, we summarize mosquito surveillance data collected over the last 20 years (2004–2023) across 59 Iowa counties to provide essential information into the spatial distribution, temporal abundance, and trap preferences of Anopheles species in the state. Further analyses of the 2 most abundant species, Anopheles punctipennis Say and Anopheles quadrimaculatus Say, reveal the additional influence of precipitation and forested habitats in defining An. punctipennis abundance. Together, we believe these results provide an increased understanding of previously neglected Anopheles species that have the potential for autochthonous malaria transmission in Iowa and that can be extended to other regions of the United States to enhance preparedness for future malaria outbreaks.

Although citizen science initiatives have been increasing globally, there is still a gap in understanding how they can result in sustainable benefits for citizen scientists.This article addresses dual goals of (i) collecting relevant data on potential vector mosquitoes and (ii) delivering learning outcomes among participants in a citizen science mosquito surveillance program. Mozzie Monitors uses an e-entomology approach to collect and identify mosquitoes of medical importance. This study used quantitative, qualitative, and mixed method approaches, comprised of before and after longitudinal surveys, in-depth interviews and descriptive assessment of mosquito attributes to assess participants' educational gains and data collection scalability. Results showed that mosquito abundance and diversity differed in each study location, with Aedes notoscriptus (Skuse) being the most common mosquito reported in all areas. Citizen scientists were predominantly women over 50 and highly educated. The before-and-after analysis showed that participants learned how to identify the most common mosquito species after participating in the program. They also improved their technical skills in mosquito photography, increasing the rates of identifiable photos. Finally, participating in this citizen science program resulted in behavior changes, with participants starting to look for mosquito eggs and larvae in their backyards to manage mosquito populations. The mixed methods used in this research showed increased participants' confidence, self-efficacy, and engagement throughout the trial. Overall, this study demonstrated the potential of Mozzie Monitors to contribute to the dual goals of mosquito data contribution and citizen scientists' educational outcomes for improved public health.

The ground-dwelling invertebrate fauna from an urban park in Belém, Amazonian Brazil, with particular reference to the subfamily Phlebotominae (Diptera: Psychodidae), were characterized. Sampling was performed from March 2022 to May 2023, with 10 emergence traps installed in 2 microhabitats, 5 in each 1: “M1,” which included surrounding (up to 1.5 m) trees with tabular roots, and “M2,” which included no trees with tabular roots. Invertebrates trapped in adhesive papers were assessed on 2 occasions/cycles (D21/D42). During 10 sampling cycles (10 traps/cycle = 100 samples), 6,490 invertebrates were captured (M1, n = 4,203; M2, n = 2,287) and classified into 5 classes and 21 orders, with Diptera (n = 2,309; 35.6%) being the most abundant. Twenty-nine specimens of the following phlebotomine species were captured: Nyssomyia antunesi (M1, n = 10; M2, n = 3), Trichophoromyia ubiquitalis (M1, n = 6; M2, n = 1), Th. brachipyga (M1, n = 0; M2, n = 2), Bichromomyia flaviscutellata (M1, n = 2; M2, n = 1) and 4 unidentified specimens (M1, n = 2; M2, n = 2). The male/female ratio was 1.08. Fractional vegetation cover was compared, and the physiochemical characteristics of the soil were compared between the microhabitats. Only temperature showed significant differences. A weak positive correlation was found between phlebotomines and other dipterans and between temperature and the amount of organic matter in the soil. Both sampled microhabitats were shown to be suitable for the development and maintenance of different invertebrates, mainly dipterans. The composition of ground-emerging phlebotomine species was similar to that previously surveyed with light traps, including species associated with the transmission of Leishmania spp.

Aedes aegypti is fast spreading across California, with over 300 cities within 22 central and southern counties being infested since its introduction in 2013. Due to its cryptic breeding habitats, control efforts have not been successful so far. This calls for innovative tools such as sterile insect technique (SIT) to reinforce the existing integrated pest management (IPM). Here, we assessed fitness, survivorship, and dose response of X-ray irradiated male Ae. aegypti in California. Locally acquired Ae. aegypti eggs were hatched and reared in temperature-controlled laboratory setting at the West Valley Mosquito and Vector Control District in Ontario, California. Freshly emerged adult male mosquitoes were manually separated using motor-operated aspirators and treated with X-ray radiation at different dosage (42–60 Gy). Dose response of irradiated males was analyzed and induced sterility determined. Survivorship of males treated with different X-ray doses was compared. Fecundity of females that mated with irradiated males at different X-ray doses was generally comparable. Overall, induced sterility increased with higher X-ray doses. Nulliparous females that mated with male Ae. aegypti treated with 55–60 Gy laid eggs with over 99% sterility. Non-irradiated male mosquitoes had higher survivorship (mean = 0.78; P = 0.0331) than irradiated mosquitoes (mean range = 0.50–0.65). The competitiveness index of irradiated males decreased with increasing X-ray treatment doses, 1.14 at 55 Gy and 0.49 at 60 Gy, and this difference was significant (P < 0.01). Irradiated males showed high survivorship and competitiveness—key for the anticipated SIT application for the control of invasive Ae. aegypti in California.

Insecticide formulations with safer environmental profiles and limited off-target effects are desirable to manage medical and veterinary pests. Silver nanoparticles are insecticidal against mosquitos, nonbiting midges, and other insects. The biting midge, Culicoides sonorensis Wirth and Jones, is a vector of agriculturally important pathogens in much of the United States, and this study aimed to examine the insecticidal properties of silver nanoparticles in larvae of this species. Mortality of third-instar larvae was assessed daily for 7 days after exposure to concentrations of silver nanoparticles, sorghum polymer particles, and hybrid silver–sorghum polymer particles. Both silver nanoparticles and silver–sorghum polymer particles were insecticidal, but sorghum polymer particles alone did not significantly contribute to larval mortality. Concentrations of 100 mg/liter of silver nanoparticles achieved >50% mortality at day 7, and 200 mg/liter treatments achieved >75% larval mortality within 24 h. The antimicrobial properties of silver nanoparticles were also examined, and culturable bacteria were recovered from larval-rearing media at 200 mg/liter but not at 400 mg/liter of silver nanoparticles. These data suggest that C. sonorensis larval mortality is primarily caused by silver nanoparticle toxicity and not by the reduction of bacteria (i.e., a larval food source). This work describes the first use of silver nanoparticles in C. sonorensis and shows the potential insecticide applications of these nanoparticles against this agricultural pest. The grain-polymer particles also successfully carried insecticidal silver nanoparticles, and their utility in loading diverse compounds could be a novel toxin delivery system for biting midges and similar pests.

Graphical Abstract

European deer keds, Lipoptena cervi (Linnaeus, 1758), are hematophagous ectoparasitic flies known to bite cervids and noncervids, including humans. To prevent deer keds from landing and biting hosts, 5 commercially available insect repellents (DEET, IR3535, oil of lemon eucalyptus (OLE), picaridin, and permethrin) and water control were evaluated to determine repellency efficacy and postexposure mortality of deer keds. While there was a significant difference between the groups tested, a post hoc analysis revealed that no treatment was significantly different from the water control. Deer ked survival was different amongst the treatments, with deer keds exposed to permethrin dying much sooner than those exposed to other treatments or control (median survival for permethrin = 0.58 h). Post-hoc pairwise comparisons revealed that deer keds exposed to DEET or IR3535 had similar survival rates (4.82 and 5.15 h, respectively). Still, there were significantly lower survival times for DEET compared to OLE (6.33 h) and picaridin (15.00 h). Deer keds exposed to the water control survived the longest (23.12 h). Overall, deer ked repellency was not significantly different from the control, but permethrin-treated clothes can effectively kill deer keds in a short amount of time, thereby protecting those who recreate outdoors or encounter animals carrying deer keds.

The house fly (Musca domestica L.) is a ubiquitous fly species commonly associated with confined animal and urban waste storage facilities. It is known for its pestiferous nature and ability to mechanically vector numerous disease-causing pathogens. Effective control of adult house fly populations has traditionally relied upon insecticidal food baits; however, due to the overuse of insecticides, resistance has proven to yield many insecticidal baits and chemical classes less effective. Imidacloprid, the most widely used neonicotinoid, has been formulated and commonly used in house fly baits for over 2 decades. However, widespread evidence of physiological and behavioral resistance to imidacloprid has been documented. While previous studies have investigated the mechanisms of behavioral resistance to imidacloprid in the house fly, it remains unclear whether behavioral resistance is specific to imidacloprid or if behavioral cross-resistance exists to other compounds within the neonicotinoid class of insecticides.The current study used no-choice and choice-feeding bioassays to examine a lab-selected imidacloprid behaviorally resistant house fly colony for cross-resistance to other insecticides in the neonicotinoid chemical class. All flies exhibited high mortality (97–100%) in no-choice assays, even when exposed to imidacloprid, indicating physiological susceptibility to all tested neonicotinoids. House flies exhibited high mortality (98–100%) in choice assays when exposed to all neonicotinoid insecticides tested besides imidacloprid. These results confirm that imidacloprid behavioral resistance is specific to the compound imidacloprid and that alternative neonicotinoids remain viable options for control. Our study showed no evidence of behavioral cross-resistance to other compounds in the neonicotinoid class.

We searched for evidence of knockdown resistance (kdr) mutations in the voltage-gated sodium channel gene of Aedes aegypti (Linnaeus) (Diptera: Culicidae) and Aedes albopictus (Skuse) (Diptera: Culicidae) mosquitoes from Panama. Conventional PCR was performed on 469 Ae. aegypti and 349 Ae. albopictus. We did not discover kdr mutations in Ae. albopictus, but 2 nonsynonymous kdr mutations, V1016I (found in 101 mosquitoes) and F1534C (found in 29 of the mosquitoes with the V1016I), were detected in Ae. aegypti.These kdr mutations were present in all specimens that were successfully sequenced for both IIS5-S6 and IIIS6 regions, which included samples collected from 8 of the 10 provinces of Panama. No other kdr mutations were found in Ae. aegypti, including V1016G, which has already been reported in Panama. Findings suggest that the V1016I-F1534C variant is prevalent in Panama, which might be related to the introduction and passive movement of mosquitoes as part of the used-tire trade. However, we cannot rule out the possibility that selection on de novo replacement of kdr mutations also partially explains the widespread distribution pattern of these mutations.These 2 ecological and evolutionary processes are not mutually exclusive, though, as they can occur in tandem. Research in Panama needs to calculate the genotypic and allelic frequencies of kdr alleles in local Ae. aegypti populations and to test whether some combinations confer phenotypic resistance or not. Finally, future studies will have to track the introduction and spreading of new kdr mutations in both Aedes species.

Graphical Abstract

The number of tick-borne disease cases continues to rise in the United States, with Lyme disease the most frequently reported vector-borne disease nationally. Practical and effective tick control tools and strategies are needed to reduce tick encounters and tick-borne disease risk. Tick management tubes have shown varying efficacy when used as part of a tick management plan. To evaluate factors contributing to the efficacy of tick management tubes, this study assessed changes in tick tube deployment on tick burden on wild-caught Peromyscus mice, a primary reservoir for the bacterium causing Lyme disease, in Pennsylvania from 2021 to 2023. Over 2 years, tick tubes were deployed starting at different times of the year, with cotton removal from the tubes assessed every 2 weeks from April to November and tick burden on wild-caught mice assessed every 2 months from April to October of each year.The effect of distance between tick management tubes was assessed in year 3 of this study, with mouse tick burden assessed pre- and post-treatment with tick tubes at varying intervals in a field setting. There was a significant reduction in mouse tick burden between treated and control transects, and pre- and post-treatment transects. Tick tube distance did not affect cotton removal or tick burden on mice. Still, cotton removal was highest in September–October, and amount removed increased the longer tick tubes were deployed in the field, highlighting the long-term benefits of using tick tubes as part of an integrated tick management plan. Future investigations to evaluate the impact of tick management tubes on tick nymph density and infection would be valuable for assessing the effectiveness of tick management tubes in reducing tick bite risk.

Stable flies, Stomoxys calcitrans (Linnaeus) (Diptera: Muscidae), are common blood-feeding ectoparasites of cows and thus potential vectors of the skin-dwelling bacterium Staphylococcus aureus, a causal agent of bovine mastitis which inflicts udder inflammation in cows. Our objectives were to determine whether stable flies (i) are attracted to disease-causing strains of S. aureus, and (ii) transmit S. aureus from infected blood to sterile blood. In 3-chamber olfactometers, five of eight S. aureus strains grown on agar and tested versus sterile agar attracted female stable flies.When flies ingested droplets of blood inoculated with S. aureus at doses of 0 (control), 10⁵ (low), 10⁷ (medium), and > 10⁹ (high) colony-forming units per milliliter and subsequently ingested sterile blood, they transmitted S. aureus to the sterile blood.The dose of S. aureus in blood droplets fed upon by flies during their first feeding bout dose-dependently affected the amount of bacteria that flies transmitted to sterile blood during their second feeding bout, but the time elapsed between feeding bouts (0 h, 1 h, 8 h, and 24 h) had no effect on the amount of microbes transmitted to sterile blood. Our data infer the existence of a positive feedback loop. First, stable flies carrying S. aureus and feeding on cows transmit S. aureus, thereby causing mastitis. As S. aureus bacteria of afflicted cows proliferate, they attract even more flies which, in turn, worsen the infection.This type of feedback loop underscores the need for effective stable fly control tactics that curtail the incidence of bovine mastitis in cows.

As the range of Ixodes scapularis Say expands, host abundance and land use can play important roles in regions where ticks and their associated pathogens are emerging. Small mammal hosts serve as reservoirs of tick-borne pathogens, with Peromyscus leucopus Rafinesque often considered a primary reservoir. A sympatric species Peromyscus maniculatus Wagner is also a competent reservoir and is notoriously difficult to differentiate from P. leucopus. Anthropogenic land use can alter host and habitat availability, potentially changing tick exposure risk. We tested the hypotheses that tick infestation and pathogen prevalence differ between the two Peromyscus spp. and that host-seeking I. scapularis density and pathogen prevalence differ across land use and ecotone gradients. We live trapped small mammals and collected ticks across 3 land-use classifications and ecotones in Maine, an emergent area for tick-borne disease. We tested each small mammal and tick sample for Borrelia burgdorferi, Anaplasma phagocytophilum, and Babesia microti. While both Peromyscus spp. serve as hosts for immature ticks, P. leucopus exhibited a higher tick infestation frequency and intensity. We did not detect any significant difference in pathogen infection prevalence between the two species. The density of I. scapularis nymphs and the density of infected nymphs did not differ significantly between land-use types, though did differ across ecotones. We also noted a significant north/south gradient, with higher tick densities and pathogen prevalence at the southern end of the study area. Our study highlights the potential variability in tick density and pathogen prevalence across fine spatial scales within an emerging region for tick-borne disease.

Ticks of the Amblyomma maculatum (Ixodida Ixodidae) complex, the Amblyomma cajennense (Ixodida Ixodidae) complex and Amblyomma ovale (Ixodida Ixodidae) are known to transmit various Rickettsia species in Colombia, but their exact distribution is unknown. We built several models based on current climate and projected future climate changes using a maximum entropy approach. A total of 314 records of the A. cajennense complex (65.9%; n = 207), A. ovale (22.9%; n = 72), and the A. maculatum complex (11.1%; n = 35) were obtained. Amblyomma ovale has a current distribution in the Pacific, Caribbean and Andean regions and could be potentially found in the Amazon. Amblyomma maculatum has a current distribution in the Andean and could potentially be found in the Caribbean and Orinoco regions. Amblyomma mixtum can be found near the Caribbean Sea and in the Pacific region, and A. patinoi is likely to be found in the Andean region and the Caribbean. In 2070, it will be possible to find an expansion of A. ovale and A. maculatum and a decrease of A. mixtum and A. patinoi. The variables that best predict the distribution of these species are isothermality (small fluctuations in temperature) and annual precipitation. Amblyomma cajennense s.l and A. ovale, A. cajennese s.l and A. patinoi, as well as A. maculatum and A. patinoi, have an important environmental sympatry. Epidemiological and acarological surveillance is crucial to investigate rickettsiosis caused by R. parkeri in A. ovale regions, by R. rickettsii in A. patinoi and A. mixtum areas, and by R. parkeri s.s in A. maculatum regions.

This study was conducted in the Gurupi Biological Reserve (REBIO-Gurupi), the largest area of Amazon rainforest in Maranhão State, Brazil. The objectives were to survey the sand fly (Diptera: Psychodidae) fauna of REBIO-Gurupi, identify blood meal sources, and investigate the presence of Leishmania (Ross, 1903) (Kinetoplastida: Trypanosomatidae) DNA. Individuals were collected using Centers for Disease Control (CDC) light traps and black and white Shannon traps in May and Jun 2022 and Jan 2023. DNA was extracted from female sand flies and subjected to amplification and sequencing of cytochrome b molecular marker (CYTB) for identification of blood meal sources and the first internal transcribed spacer (ITS-1) of ribosomal DNA for Leishmania detection. A total of 514 sand flies individuals were sampled, of which 93 were identified at the genus or series level (9 taxa) and 421 were identified at the species level (24 taxa). Psychodopygus davisi (Root, 1934) (41.1%), Nyssomyia antunesi (Coutinho, 1939) (10.3%), and Psychodopygus (Mangabeira, 1941) Chagasi Series Barretto, 1962 (9.7%) were the most frequently collected. Human (Homo sapiens, Primates, Hominidae) and tapir (Tapirus terrestris, Perissodactyla, Tapiridae) DNA was detected in 10 female sand flies. Leishmania (Leishmania) infantum Cunha and Chagas, 1937 DNA was detected in 2 specimens of Ps. davisi. Given the presence of vectors of Leishmania in REBIO-Gurupi, it is imperative to conduct more comprehensive studies on the interactions among sand flies, Leishmania, and pathogen reservoirs in the area.

Graphical Abstract

Mosquito surveillance is critical for actively tracking the location and monitoring population levels and the threat of mosquito-borne disease. Although light-emitting diodes (LEDs) light traps have grown in popularity, there is still a limited understanding of the application of light wavelengths for trapping nocturnally active wild mosquitoes in forest ecotypes.This study evaluated the performance of different UV wavelengths in trapping mosquito populations in a forested mountainous area in Nakhon Ratchasima province, Thailand. Traps with different UV wavelengths were deployed in 6 locations, following a 6 × 6 Latin square replicated 6 times over a total of 36 nights. Light traps were operated between 18:00 and 06:00 h from October 2022 to August 2023. Mosquitoes were separately collected from individual traps every 4 h at 22.00, 2.00, and 6.00 h. Mosquitoes were killed by placing in a freezer (– 20 °C) for at least 30 min and then were morphologically identified using illustrated keys for adult females.Traps fitted with the LED 365 wavelength light source were the most effective in capturing 790 (23.66%) of the total mosquitoes collected, followed by the UV fluorescent 632 (18.93%), with the other 4 LED wavelengths collecting between 16.89% (LED 385) and 12.64% (LED 375) of the mosquitoes. Culex was the most common genus, representing 56.00% of total mosquito abundance. LED 365 and LED 385 were comparable to the UV fluorescent traps (the standard reference). Optimal trapping times were during 18:00–22:00 h. Compared to the other wavelengths, LED 365 was significantly more effective at capturing Coquillettidia and Culex mosquitoes than the UV-based traps.

Leishmaniasis are zoonosis widely spread in Brazil, caused by the protozoan of the genus Leishmania, which includes several species. The disease manifests itself in the visceral or tegumentary form, and the main reservoir is the dogs. Manaus is the largest city in the Brazilian Amazon region, and despite the importance of the municipality, practically nothing is known about leishmaniosis in humans and animals. The objective of this study was to evaluate the occurrence and risk factors associated with the presence of Leishmania infantum in domiciliated dogs from Manaus. Molecular (polymerase chain reaction) and serological (immunofluorescent antibody test) methods were used as an indication of the circulation of the parasite. Blood samples for 154 domiciled dogs were obtained, and prevalence ratio and analysis of the variables were performed. Serum antibodies anti-Leishmania spp. were detected in 20.8% (95% CI: 14.4%–27.2%). Access to the street and zone of residence (P < 0.01) were associated with higher seropositivity. Molecular diagnosis for L. infantum detected positivity in 60 (39%) of the 154 (95% CI: 31.3%–46.7%) animals, and the variables street access, contact with dogs, and zone of residence were associated with higher frequencies of positivity (P < 0.05). Both serology and molecular diagnosis detected positive dogs in the municipality. This is the first description of the circulation of L. infantum infecting dogs in Manaus. As the municipality is classified as nonendemic, studies of isolation and characterization of the isolate must be done urgently.

Permethrin-treated clothing is often recommended as a first line of defense against tick-borne diseases. In 2012, the permethrin factory-treated Army Combat Uniform was first made available to active duty Soldiers, Army National Guard, Army Reserve Enlisted Soldiers, and the Senior/Junior Reserve Officers Training Corps. Subsequently, Air Force and Marine Corps personnel were also offered permethrin factory-treated uniforms. Here, we use the passive surveillance data collected through the MilitaryTick Identification/Infection Confirmation Kit (MilTICK) program to determine the effectiveness of permethrin-treated uniforms at protecting Department of Defense personnel from exposure to tick-borne pathogens in the United States. We analyzed whether submissions by self-reported users of the permethrin-treated uniforms had smaller proportions of engorged ticks, certain cohorts of MilTICK users were better protected than others, and specific tick species were better repelled than others. We found that permethrin use resulted in significantly lower proportions of engorged ticks submitted across MilTICK users. Army and Army National Guard personnel reported more permethrin-treated uniform use than other services. For submissions from active duty personnel serving in uniform, the proportion of tick engorgement in the presence of permethrin increased over time, possibly indicating that permethrin-treated uniforms suffer from reduced performance over the life of the garment. We also found that while permethrin reduced all tick species' ability to feed until engorgement or repletion, blacklegged tick adult females were better able to resist permethrin's lethal effects than lone star tick and American dog tick adult females. Permethrin-treated clothing plays an important role in keeping military personnel safe from tick-borne diseases.

The sand fly of the genus Bichromomyia (Galati, 1995) includes 3 subspecies considered vectors of Leishmania, which share high morphological similarity. Through information from the Cytochrome Oxidase Subunit I (COI) gene, we provide complementary evidence to support that Bichromomyia olmeca olmeca, and Bichromomyia olmeca bicolor, should be raised to nominal species status. We recovered specimens of Bi. o. olmeca from Quintana Roo, Tabasco, and Oaxaca, Mexico, supply 17 new COI sequences, and also incorporate GenBank sequences for other Bichromomyia species. After a Maximum Likelihood (ML) analysis, all Bichromomyia species clustered with a bootstrap of 100%, although sequences of Bichromomyia flaviscutellata were divided into 2 clusters with an interspecific range distance of 11.16% between them, which confirm cryptic species in Brazil. The genetic distance of Bi. o. olmeca compared to related subspecies ranged between 12.59% and 14.64%. A total of 29 haplotypes (Hd = 0.987; π = 0.08783; S = 136) were recovered from the Bichromomyia sequences. Results of the TC network were consistent with the ML analysis, supporting that subspecies of Bichromomyia are genetically distinct and deserve being raised to valid species category: Bichromomyia olmeca (Vargas & Díaz-Nájera) and Bichromomyia bicolor (Fairchild & Theodor).

Graphical Abstract

Wildlife are hosts of ectoparasites, such as fleas and ticks that may transmit human and animal pathogens. Little is known about the ecology of many ectoparasite species native to southern Texas, or their role in pathogen maintenance and transmission. Much attention has been given to the role of nonnative nilgai antelope as cattle fever tick hosts and agents of dispersal, but little attention has been given to other ectoparasites that may utilize nilgai antelope as hosts. As southern Texas is a hot-spot for flea-borne (murine) typhus, it is important to examine flea species presence, abundance, and host use in this region. Fleas were opportunistically collected during wildlife depredation activities, from hunter-harvested animals, or during handling in the course of other research activities in several southern Texas counties. A total of 9 wildlife species were sampled, from which 3 flea species were identified. A total of 83 Pulex porcinus (Jordan and Rothschild) were collected from nilgai, coyotes, bobcats, javelina, feral swine, and a black-tailed jackrabbit. In total, 9 Euhoplopsyllus glacialis affinis (Baker) were collected from cottontail rabbits, and 1 Echidnophaga gallinacea (Westwood) was collected from a raccoon. To our knowledge, this represents the first report of fleas from nilgai antelope. Pulex porcinus, although often considered a specialist species, was collected from a wide range of hosts, including 2 (nilgai antelope and black-tailed jackrabbit) that represent new host records for this species. The role of P. porcinus as a pathogen vector is unknown, but its apparent abundance in this region warrants further investigation.