Studies on the timing of anopheline host-seeking are important for understanding mosquito ecology, behaviors, and possible role in disease transmission. To study the evening crepuscular host-seeking activity of anophelines and the effects of moonlight, anopheline mosquitoes were collected with light traps settled in a livestock area in the Brazilian Cerrado region. Traps (Silva traps) were placed next to animal enclosures at 1.5 m asl. The research was divided in 2 experiments: the first experiment (12 nights) comprised 2 trapping periods, one from 6 PM to 7 PM and one from 7 PM to 6 AM, and the second experiment (16 evenings) divided in three 20-min intervals based on the 3 twilight phases (civil: 6–6:20 PM; nautical: 6:20–6:40 PM; and astronomical: 6:40–7 PM). A total of 2,815 anopheline mosquitoes and 9 species were found.The main species were Anopheles triannulatus s.l., An. argyritarsis, An. goeldii, and An. evanse. Host-seeking mosquitoes were more frequently active during the first hour after sunset, with a significant peak in the second 20-min interval. After that, a decrease in the number of individuals was observed from the astronomical twilight onwards. Moonlight did not affect the evening flight activity of anophelines. By using LED-based passive light traps, the evening arrival time of anophelines at blood-feeding sites was demonstrated, and it may be a key time window for malaria vector control interventions.

In the search for effective and environmentally friendly mosquito control agents, we have examined natural sources, such as microbes and plants, and the synthetic analogs of natural products.These plants and microbes have evolved in their ecological niches to produce defensive compounds against other competing organisms in their surroundings such as microbes, plants, and insects as a means to enhance their survival. Thus, some of these plants and microbes have bioactive compounds with insecticidal, fungicidal, and phytotoxic activities. In our previous research, we successfully isolated bioactive constituents from natural sources. We have carried out synthetic modifications and total synthesis of marginally active isolated compounds to achieve significantly higher active compounds. We have focused on plants in the Rutaceae family as the members of this family are known to possess bioactive compounds with algicidal, antifungal, insecticidal, and fungicidal activities. In this article, we report the isolation and structure elucidation of mosquito larvicidal constituents from Poncirus trifoliata (Rutaceae) root extract.

Around the world, mosquitoes continue to transmit disease-causing pathogens and develop resistance to insecticides. We previously discovered that a generally regarded as safe (GRAS) compound, 1,2-propanediol, reduces adult mosquito survivorship when ingested. In this study, we assess and compare 5 more chemically related compounds for mosquito lethality and 8 GRAS sugar substitutes to determine toxicity. We conducted a series of feeding assays to determine if ingesting the compounds influenced mosquito mean survivorship in locally collected lab-reared populations of Aedes aegypti (Diptera, Culicidae, Linnaeus, 1762) and Aedes albopictus (Diptera, Culicidae, Skuse, 1894) mosquitoes. Our results indicate that 1,2-propanediol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,3-propanediol, DL-dithiothreitol, acesulfame potassium, allulose, erythritol, sodium saccharin, stevia, and sucralose significantly reduced the mean survivorship of one or both species. Short-term trials with the most toxic compounds revealed that they could substantially affect survivorship after 24 h. We also found that there were different responses in the 2 species and that in several experimental conditions, male mosquitoes expired to a greater extent than female mosquitoes. These findings indicate that several of the compounds are toxic to mosquitoes. Further study is required to determine their effectiveness in attractive toxic sugar baits (ATSBs) as a potential component of population control strategies.

The massive and inappropriate use of synthetic insecticides is causing significant and increasing environmental disruption.Therefore, developing effective natural mosquitocidal compounds could be an alternative tool for malarial vector control.The present study investigates the larvicidal and adulticidal effect of methanol and acetone extracts of leaves from Lippia chevalieri, Lippia multiflora, Cymbopogon schoenanthus, and Lantana camara against Anopheles arabiensis, to control the most widespread vector transmitting malaria in sub-Saharan. Africa. Extracts were evaluated following WHO modified test procedure against third- to fourth-instar larvae and, non-blood-fed females from 3- to 5-day-old field populations of An. arabiensis under laboratory conditions usingWHO larval and CDC bottle bioassays, respectively. Mortality was recorded after 24-h exposure and several compounds were identified in the extracts. The methanolic and acetonic extracts of L. camara were effective against larvae showing lethal concentrations to 50% (LC₅₀) of the population, at 89.48 and 58.72 ppm, respectively.The acetonic extracts of C. schoenanthus and L. chevalieri showed higher toxicities LC₅₀s of 0.16% and 0.22% against female adults, respectively. The methanolic extracts of L. multiflora and L. chevalieri LC₅₀s were effective at 0.17% and 0.27%, respectively, against female adults.These results indicate that the plant extracts tested may represent effective means to control An. arabiensis when used to treat the surface of the marshes.

The yellow fever mosquito, Aedes aegypti L., can transmit several pathogens responsible for human diseases. With insecticide resistance development becoming a concern, alternative control strategies are needed for Ae. aegypti. Sterile insect technique (SIT) is an increasingly popular option being explored. However, logistical issues in mass production and sterilization make it difficult to maintain a SIT program. Male mosquitoes are typically irradiated as pupae because this is the earliest developmental point at which females can be separated from males, but asynchrony in pupation and high variability in pupal responses to irradiation based on pupal age make it difficult to sterilize mass quantities of pupae on a regular schedule in a rearing facility.Young adult mosquitoes have wider windows for irradiation sterilization than pupae, which can allow facilities to have fixed schedules for irradiation. We produced a workflow for adult Ae. aegypti irradiation in a mosquito control district with an operational SIT program that currently irradiates pupae. The impacts of chilling, compaction, and radiation dose on survival were all assessed before combining them into a complete adult irradiation protocol. Males chilled up to 16 h prior to compaction and compacted to 100 males/cm³ during radiation resulted in low mortality. Males irradiated as adults had increased longevity and similar sterility compared to males irradiated as pupae. Additionally, males sterilized as adults were more sexually competitive than males sterilized as pupae.Thus, we have shown that irradiating adult males can be a viable option to increase the efficiency of this operational mosquito SIT program.

Numerous studies have assessed the efficacy of environmentally based control methods to suppress populations of the blacklegged tick (Ixodes scapularis Say), but few of these estimated the cost of control. We estimated costs for a range of tick control methods (including habitat management, deer exclusion or population reduction, broadcast of acaricides, and use of host-targeted acaricides) implemented singly or in combination and applied to a model community comprising 320 residential properties and parklands. Using the high end for cost ranges, tick control based on a single method was estimated to have mean annual costs per household in the model community ranging from $132 for treating only forest ecotone with a broadcast synthetic acaricide to kill host-seeking ticks (or $404 for treating all residential forested habitat) to >$2,000 for deployment of bait boxes (SELECT TCS) across all residential tick habitat to treat rodents topically with acaricide to kill infesting ticks. Combining different sets of multiple methods in an integrated tick management program placed the annual cost between $508 and 3,192 annually per household in the model community, underscoring the disconnect between what people in Lyme disease endemic areas say they are willing to pay for tick control (not more than $100–150 annually) and the actual costs for tick control. Additional barriers to implementing community-based tick management programs within residential communities are discussed.

Aedes notoscriptus (Skuse) is a container-inhabiting mosquito endemic to Australia that vectors arboviruses and is suspected to transmit Mycobacterium ulcerans, the cause of Buruli ulcer. We evaluated the effectiveness of the In2Care station, which suppresses mosquito populations via the entomopathogenic fungus, Beauveria bassiana, and the insect growth regulator pyriproxyfen, the latter of which is autodisseminated among larval habitats by contaminated mosquitoes. A field trial was conducted using 110 In2Care stations in a 50,000 m² area and results were compared to 4 control areas that did not receive the treatment. Efficacy was evaluated by comparing egg counts and measuring larvicidal impact in surrounding breeding sites. Laboratory experiments validated the effect of B. bassiana on adult survival. Results of this field trial indicate that, 6 wk after the In2Care stations were deployed, treatment site ovitraps contained 43% fewer eggs than control site ovitraps, and 33% fewer eggs after 10 wk, suggesting that the In2Care station was able to reduce the egg density of Ae. notoscriptus. Population reduction remained evident for up to 3 wk after In2Care stations were removed. Treatment site ovitraps had significantly fewer Ae. notoscriptus eclosing than control site ovitraps, confirming the pyriproxyfen autodissemination feature of the stations. An average reduction of 50% in adult eclosion was achieved. Exposure to B. bassiana resulted in four-times higher mortality among adult mosquitoes. Additionally, using fresh In2Care nettings led to an 88% decrease in average survival compared to 4-wk-old nettings. The use of In2Care stations has potential for suppressing Ae. notoscriptus egg density.

Lagomorphs—principally rabbits and hares—have been implicated as hosts for vectors and reservoirs for pathogens associated with multiple rickettsial diseases. Western North America is home to diverse rickettsial pathogens which circulate among multiple wild and domestic hosts and tick and flea vectors. The purpose of this study was to assess lagomorphs and their ectoparasites in 2 locations in northern Baja California, Mexico, for exposure to and infection with rickettsial organisms. In total, 55 desert cottontail rabbits (Sylvilagus audubonii) (Baird) and 2 black-tailed jackrabbits (Lepus californicus) (Gray) were captured. In Mexicali, ticks were collected from 44% (14/32) of individuals, and were exclusively Haemaphysalis leporispalustris Neumann (Acari: Ixodidae); in Ensenada, ticks were collected from 70% (16/23) individuals, and 95% were Dermacentor parumapertus. Euhoplopsyllus glacialis affinis Baker (Siphonaptera: Pulicidae) fleas were collected from 72% of rabbits and 1 jackrabbit from Mexicali, while the few fleas found on hosts in Ensenada were Echidnophaga gallinacea Westwood (Siphonaptera: Pulicidae) and Cediopsylla inaequalis (Siphonaptera: Pulicidae). Rickettsia bellii was the only rickettsial organism detected and was identified in 88% of D. parumapertus and 67% of H. leporispalustris ticks from Ensenada. A single tissue sample from a jackrabbit was positive for R. belli (Rickettsiales: Rickettsiaceae). Hosts in Ensenada had a significantly higher prevalence of rickettsial antibodies than hosts in Mexicali (52.3% vs. 21.4%). Although R. bellii is not regarded as pathogenic in humans or other mammals, it may contribute to immunity to other rickettsiae. The marked difference in distribution of ticks, fleas, and rickettsial exposure between the 2 locations suggests that disease transmission risk may vary markedly between communities within the same region.

Tick-borne diseases have increased significantly in Europe and Spain in recent years. One strategy explored for tick surveillance and control is the study of the microbiota.The focus is on understanding the relationships between pathogens and endosymbionts within the microbiota and how these relationships can alter these arthropods' vectorial capacity. Thus, it is pivotal to depict the bacterial communities composing the microbiota of ticks present in specific territories. This work aimed to describe the microbiota present in 29 adult individuals of 5 tick species collected from 4 provinces of Castilla y Leon in northwestern Spain from 2015 to 2022. DNA extraction and sequencing of the V4 hypervariable region of 16S-rRNA was performed on the tick samples, with subsequent analysis of diversity, taxonomic composition, and correlations between genera of microorganisms.There were no differences in the alpha diversity of microbiota by tick species, nor were compositional changes evident at the phylum level for microorganisms. However, interindividual differences at the microbial genus level allowed spatial differentiation of the 5 tick species included in the study. Correlation analyses showed complex interactions between different genera of microbiota members.These findings provide an initial insight into the composition of the gut microbiota of various tick species in northwestern Spain, which can contribute to establishing surveillance and control measures to reduce diseases such as rickettsiosis, Lyme disease, and Crimean-Congo hemorrhagic fever.

In the present study, the temporal dynamics of the main vector of Leishmania braziliensis, Nyssomyia whitmani, was measured by monthly captures of phlebotominae sandflies during 5 consecutive years (from 2011 to 2016) in the Paranaense region of South America.The captures were performed in environments where the human–vector contact risk is high: domiciliary and peridomiciliary environments in a rural area endemic of tegumentary leishmaniasis. Nyssomyia whitmani was recorded as the dominant species of the phlebotominae ensemble in all domiciliary and peridomiciliary environments (House, Chicken Shed, Pigsty, and Forest Edge). Using generalized additive models, intra- and interannual fluctuations were observed, modulated by meteorological variables such as the minimum temperature and the accumulated precipitation 1 wk prior to capture. The installation of a pigsty by the farmer during the study period allowed us to observe and describe the so-called “pigsty effect” where the Ny. whitmani population was spatially redistributed, turning the pigsty as the environment that obtained the highest phlebotominae record counts, thus maintaining the farm overall abundance, supporting the idea that the environmental management of the peridomicile could have an impact on the reduction of epidemiological risk by altering the spatial distribution of the phlebotominae ensemble in the environments.

Rapid environmental change in Alaska and other regions of the Arctic and sub-Arctic has raised concerns about increasing human exposure to ticks and the pathogens they carry. We tested a sample of ticks collected through a combination of passive and active surveillance from humans, domestic animals, and wildlife hosts in Alaska for a panel of the most common tick-borne pathogens in the contiguous United States to characterize the diversity of microbes present in this region. We tested 189 pooled tick samples collected in 2019-2020 for Borrelia spp., Anaplasma spp., Ehrlichia spp., and Babesia spp. using a multiplex PCR amplicon sequencing assay. We found established populations of Ixodes angustus Neumann (Acari: Ixodidae), Ixodes uriae White (Acari: Ixodidae), and Haemaphysalis leporispalustris Packard (Acari: Ixodidae) in Alaska, with I. angustus found on a variety of hosts including domestic companion animals (dogs and cats), small wild mammals, and humans. Ixodes angustus were active from April through October with peaks in adult and nymphal activity observed in summer months (mainly July). Although no known human pathogens were detected, Babesia microti-like parasites and candidatus Ehrlichia khabarensis were identified in ticks and small mammals. The only human pathogen detected (B. burgdorferi s.s.) was found in a tick associated with a dog that had recently traveled to New York, where Lyme disease is endemic. This study highlights the value of a combined passive and active tick surveillance system to detect introduced tick species and pathogens and to assess which tick species and microbes are locally established.

West Nile virus (WNV) invaded the continental United States over 20 years ago and continues to cause yearly seasonal outbreaks of human and veterinary disease. In the suburbs of Chicago, Illinois, ultra-low volume (ULV) truck-mounted adulticide spraying frequently is performed to reduce populations of Culex restuans Theobald and Cx. pipiens L. mosquitoes (Diptera: Culicidae) in an effort to lower the risk of WNV transmission. The effectiveness of this control method has not been rigorously evaluated, and evidence for Culex population reduction after ULV adulticide spraying has been inconclusive. Therefore, we evaluated the results of 5 sequential weekly truck-mounted adulticide applications of Zenivex® E20 (etofenprox) in 2 paired sites located in Cook County, IL, during the summer of 2018. Mosquito population abundance, age structure, and WNV infection prevalence were monitored and compared between paired treatment and nearby control sites. Adulticide treatment did not result in consistent short-term or long-term reductions in target WNV vector Culex abundance. However, there was a significant increase in the proportion of nulliparous females in the treated sites compared to control sites and a decrease in Cx. pipiens WNV infection rates at one of the treated sites. This evidence that ULV adulticide spraying altered the age structure and WNV infection prevalence in a vector population has important implications for WNV transmission risk management. Our findings also underscore the importance of measuring these important indicators in addition to abundance metrics when evaluating the efficacy of control methods.

Culicoides-borne viruses are an important arbovirus group causing bovine diseases. During 2012–2019, 2,525 pools consisting of 108,937 specimens of vectors were subjected to PCR detection of bovine arbovirus belonging to Orthobunyavirus, Orbivirus, and Ephemerovirus. Twelve virus RNAs, of which 6, that is, Shuni virus, Shamonda virus, and Sathuperi virus in Orthobunyavirus and Sathuvachari virus and epizootic hemorrhagic disease virus serotypes 4 and 7 in Orbivirus were detected for the first time in the area. Potential vector species were evaluated by the minimum infection rate, and the population abundance of Culicoides oxystoma, Culex tritaeniorhynchus, and Anopheles sinensis indicated that they were the main potential vector species in dairy farms inTaiwan.

The blacklegged tick, Ixodes scapularis Say, is one of the most important vectors of tick-borne disease agents in North America. Accordingly, it is crucial to know this species local composition, abundance, and seasonality (phenology) to help prevent tick-borne illnesses. The phenology of adult I. scapularis is reported in the scientific literature from October through May. Data from previous research in Mississippi have all supported this time frame for adult blacklegged tick activity. However, in this study, we report a collection of 13 I. scapularis from 9 widely separated areas in Mississippi during the summer and early fall of 2022 (June, July, and September). These findings are remarkable, even enigmatic, and should prompt further investigation.

We describe the first known established Asian longhorned tick (ALT) (Acari: Ixodidae: Haemaphysalis longicornis Neumann) population in Ohio, USA. In mid-summer 2021, we collected ALTs from an infested pasture in response to an alert that grazing cattle had been infested with ticks, and 3 of them had died. No ALTs were reported following pesticide treatment of the pasture in fall 2021. In the laboratory, we identified 9,287 ticks to species, representing all 3 life stages, as ALTs and tested 100 of the adult females for infectious agents relevant to human and animal health, including Theileria orientalis, a cattle disease agent. Eight field-collected ticks were positive for Anaplasma phagocytophilum (n = 100, 8%); no other infectious agents were detected. Active environmental surveillance showed the return of ALTs in June 2022 despite the tick control efforts in 2021. As ALTs continue to expand their range in the United States, active and passive surveillance studies will be needed to characterize their evolving role in human and animal health.

We evaluated the relative effectiveness of the natural product acaricide Essentria IC³ and the entomopathogenic fungal acaricide BotaniGard ES to suppress host-seeking Ixodes scapularis Say and Amblyomma americanum (L.) nymphs when applied with low-pressure backpack and high-pressure sprayers. Essentria IC³ applied by backpack sprayer out-performed high-pressure applications, while the opposite was true for treatments with BotaniGard ES. We were unable to demonstrate consistently greater efficacy using high-pressure applications, and neither of the acaricides or application methods provided substantial (>90%) levels of control at 7 days postapplication.