In recent decades, tickborne disease (TBD) cases and established populations of medically important ticks have been reported over expanding geographic areas, and an increasing number of tickborne bacteria, viruses, and protozoans have been recognized as human pathogens, collectively contributing to an increasing burden of TBDs in the United States.The prevention and diagnosis of TBDs depend greatly on an accurate understanding by the public and healthcare providers of when and where persons are at risk for exposure to human-biting ticks and to the pathogens these ticks transmit. However, national maps showing the distributions of medically important ticks and the presence or prevalence of tickborne pathogens are often incomplete, outdated, or lacking entirely. Similar deficiencies exist regarding geographic variability in host-seeking tick abundance. Efforts to accurately depict acarological risk are hampered by lack of systematic and routine surveillance for medically important ticks and their associated human pathogens. In this review, we: 1) outline the public health importance of tick surveillance; 2) identify gaps in knowledge regarding the distributions and abundance of medically important ticks in the United States and the presence and prevalence of their associated pathogens; 3) describe key objectives for tick surveillance and review methods appropriate for addressing those goals; and 4) assess current capacity and barriers to implementation and sustainability of tick surveillance programs.

Tickborne diseases are an increasing public health threat in the United States. Prevention and diagnosis of tickborne diseases are improved by access to current and accurate information on where medically important ticks and their associated human and veterinary pathogens are present, their local abundance or prevalence, and when ticks are actively seeking hosts. The true extent of tick and tickborne pathogen expansion is poorly defined, in part because of a lack of nationally standardized tick surveillance. We surveyed 140 vectorborne disease professionals working in state, county, and local public health and vector control agencies to assess their 1) tick surveillance program objectives, 2) pathogen testing methods, 3) tick control practices, 4) data communication strategies, and 5) barriers to program development and operation. Fewer than half of respondents reported that their jurisdiction was engaged in routine, active tick surveillance, but nearly two-thirds reported engaging in passive tick surveillance. Detection of tick presence was the most commonly stated current surveillance objective (76.2%). Most of the programs currently supporting tick pathogen testing were in the Northeast (70.8%), Upper and Central Midwest (64.3%), and the West (71.4%) regions.The most common pathogens screened for were Rickettsia spp. (Rickettsiales: Rickettsiaceae) and bacterial and viral agents transmitted by Ixodes (Acari: Ixodidae) ticks. Only 12% of respondents indicated their jurisdiction directly conducts or otherwise financially supports tick control. Responses indicated that their ability to expand the capacity of tick surveillance and control programs was impeded by inconsistent funding, limited infrastructure, guidance on best practices, and institutional capacity to perform these functions.

Spirochetes of the family Borreliaceae are, with one exception, tick-borne pathogens of a variety of vertebrates. The family at present comprises two genera: Borrelia (Swellengrebel), which includes the agents of relapsing fever, avian spirochetosis, and bovine borreliosis, and Borreliella (Gupta et al.), which includes the agents of Lyme disease and was formerly known as ‘Borrelia burgdorferi sensu lato complex'.The two genera are distinguished not only by their disease associations but also biological features in the tick vector, including tissue location in unfed ticks and transovarial transmission. Borrelia species transmitted by argasid (soft) ticks tend to have more exclusive relationships with their tick vectors than do other Borrelia species and all Borreliella species that have ixodid (hard) ticks as vectors.The division of genera is supported by phylogenomic evidence from whole genomes and by several specific molecular markers. These distinguishing phylogenetic criteria also applied to three new species or isolates of Borrelia that were discovered in ixodid ticks of reptiles, a monotreme, and birds. Although the deep branching of the family from other spirochetes has been a challenge for inferences about evolution of the family, the discovery of related microorganisms in the gut microbiota of other arachnids suggests an ancestral origin for the family as symbionts of ticks and other arachnids.

Within the past 30 yr molecular assays have largely supplanted classical methods for detection of tick-borne agents. Enhancements provided by molecular assays, including speed, throughput, sensitivity, and specificity, have resulted in a rapid increase in the number of newly characterized tick-borne agents.The use of unbiased high throughput sequencing has enabled the prompt identification of new pathogens and the examination of tick microbiomes.These efforts have led to the identification of hundreds of new tick-borne agents in the last decade alone. However, little is currently known about the majority of these agents beyond their phylogenetic classification. Our article outlines the primary methods involved in tick-borne agent discovery and the current status of our understanding of tick-borne agent diversity.

The global climate has been changing over the last century due to greenhouse gas emissions and will continue to change over this century, accelerating without effective global efforts to reduce emissions. Ticks and tick-borne diseases (TTBDs) are inherently climate-sensitive due to the sensitivity of tick lifecycles to climate. Key direct climate and weather sensitivities include survival of individual ticks, and the duration of development and host-seeking activity of ticks. These sensitivities mean that in some regions a warming climate may increase tick survival, shorten life-cycles and lengthen the duration of tick activity seasons. Indirect effects of climate change on host communities may, with changes in tick abundance, facilitate enhanced transmission of tick-borne pathogens. High temperatures, and extreme weather events (heat, cold, and flooding) are anticipated with climate change, and these may reduce tick survival and pathogen transmission in some locations. Studies of the possible effects of climate change on TTBDs to date generally project poleward range expansion of geographical ranges (with possible contraction of ranges away from the increasingly hot tropics), upslope elevational range spread in mountainous regions, and increased abundance of ticks in many current endemic regions. However, relatively few studies, using long-term (multi-decade) observations, provide evidence of recent range changes of tick populations that could be attributed to recent climate change. Further integrated ‘One Health’ observational and modeling studies are needed to detect changes in TTBD occurrence, attribute them to climate change, and to develop predictive models of public- and animal-health needs to plan for TTBD emergence.

The incidence of tick-borne diseases has increased in recent decades and accounts for the majority of vectorborne disease cases in temperate areas of Europe, North America, and Asia. This emergence has been attributed to multiple and interactive drivers including changes in climate, land use, abundance of key hosts, and people's behaviors affecting the probability of human exposure to infected ticks. In this forum paper, we focus on how land use changes have shaped the eco-epidemiology of Ixodes scapularis-borne pathogens, in particular the Lyme disease spirochete Borrelia burgdorferi sensu stricto in the eastern United States. We use this as a model system, addressing other tick-borne disease systems as needed to illustrate patterns or processes. We first examine how land use interacts with abiotic conditions (microclimate) and biotic factors (e.g., host community composition) to influence the enzootic hazard, measured as the density of host-seeking I. scapularis nymphs infected with B. burgdorferi s.s. We then review the evidence of how specific landscape configuration, in particular forest fragmentation, influences the enzootic hazard and disease risk across spatial scales and urbanization levels. We emphasize the need for a dynamic understanding of landscapes based on tick and pathogen host movement and habitat use in relation to human resource provisioning. We propose a coupled natural-human systems framework for tick-borne diseases that accounts for the multiple interactions, nonlinearities and feedbacks in the system and conclude with a call for standardization of methodology and terminology to help integrate studies conducted at multiple scales.

Wildlife vertebrate hosts are integral to enzootic cycles of tick-borne pathogens, and in some cases have played key roles in the recent rise of ticks and tick-borne diseases in North America. In this forum article, we highlight roles that wildlife hosts play in the maintenance and transmission of zoonotic, companion animal, livestock, and wildlife tick-borne pathogens. We begin by illustrating how wildlife contribute directly and indirectly to the increase and geographic expansion of ticks and their associated pathogens. Wildlife provide blood meals for tick growth and reproduction; serve as pathogen reservoirs; and can disperse ticks and pathogens—either through natural movement (e.g., avian migration) or through human-facilitated movement (e.g., wildlife translocations and trade). We then discuss opportunities to manage tick-borne disease through actions directed at wildlife hosts. To conclude, we highlight key gaps in our understanding of the ecology of tick–host interactions, emphasizing that wildlife host communities are themselves a very dynamic component of tick–pathogen–host systems and therefore complicate management of tick-borne diseases, and should be taken into account when considering host-targeted approaches. Effective management of wildlife to reduce tick-borne disease risk further requires consideration of the ‘human dimensions’ of wildlife management.This includes understanding the public's diverse views and values about wildlife and wildlife impacts—including the perceived role of wildlife in fostering tick-borne diseases. Public health agencies should capitalize on the expertise of wildlife agencies when developing strategies to reduce tick-borne disease risks.

Lyme and other tick-borne diseases are increasing in the United States. Development of tick control tools have focused primarily on the blacklegged tick, Ixodes scapularis Say. Application of acaricides or entomopathogenic fungal agents to kill host-seeking ticks or ticks on rodents can suppress I. scapularis abundance in residential landscapes, but evidence is lacking for impact on human tick bites or tick-borne disease. Similar studies remain limited for the lone star tick, Amblyomma americanum (L.). Other knowledge gaps include how well homeowners and pest control companies perform in the broadcast application of tick-killing products, relative to high efficacy reported in research studies, and the tick-killing potential of natural product formulations exempt from Environmental Protection Agency registration. Area-wide control based on preventing ticks from feeding on their main reproductive host, the white-tailed deer, can suppress populations of both I. scapularis and A. americanum. Some studies also suggest an impact on Lyme disease cases, but this needs to be further validated in larger-scale intervention studies. The effectiveness, scale, cost, and implementation of various tick management strategies are important considerations in efforts to reduce human tick encounters and tick-borne disease. Additional barriers include weak incentives for industry and academia to develop, test, and register new tick and pathogen control technologies, including vaccines targeting humans, tick reproductive hosts, or wildlife pathogen reservoirs. Solutions will need to be ‘two-pronged': improving the tick and pathogen control toolbox and strengthening the public health workforce engaging in tick control at local and state levels.

The one-host cattle fever tick, Rhipicephalus (Boophilus) annulatus (Say), and southern cattle fever tick, Rhipicephalus (Boophilus) microplus (Canestrini), are important ectoparasitic pests of cattle, Bos taurus L., mostly for transmitting the causal agents of bovine babesiosis. Bovine babesiosis inflicted substantial cattle production losses in the United States before the vectors were eliminated by 1943, with the exception of a Permanent Quarantine Zone in South Texas, a buffer along the Mexico border where the invasive ixodids remain. As suitable hosts, infested white-tailed deer and nilgai antelope populations disperse R. annulatus and R. microplus, which increases the risk for emergence of bovine babesiosis in the United States. A R. microplus incursion first detected in 2016 on the SouthTexas coastal plain wildlife corridor involved infestations on cattle, nilgai antelope, white-tailed deer, and vegetation. Efforts at passive sampling of Rhipicephalus (Boophilus) spp. on hosts are concentrated in the Permanent Quarantine Zone. Hence, a knowledge gap exists on the full extent of the recent incursions. Area-wide, systematic, active sampling and supportive research, involving the Permanent Quarantine Zone, Temporary Quarantine Zone, most of the coastal plain, and other parts of Texas outside of the quarantine zones, are needed to bridge the knowledge gap. Herein, we provide research perspectives and rationale to develop and implement systematic active sampling that will provide an increasingly accurate assessment of Rhipicephalus (Boophilus) spp. distribution in Texas. We suggest that this is essential to advance integrated vector-borne animal disease eradication approaches for keeping cattle free of bovine babesiosis.

Diapause, a period of arrested development that allows mosquitoes to survive inhospitable conditions, is triggered by short daylengths in temperate mosquitoes. Different populations of mosquitoes initiate diapause in response to a specific photoperiod, or daylength, resulting in population-specific differences in annual cycles of abundance. The photoperiod that causes approximately 50% of a population to initiate diapause is known as the critical photoperiod (CPP).The autumn daylength corresponding to the CPP in the field likely marks the day beyond which the photoperiods would trigger and maintain 50% or more diapause incidence in a population, although temperature, diet, and other factors can impact diapause initiation. In the Northern Hemisphere, northern populations of mosquitoes experience lower temperatures earlier in the year and must be triggered into diapause by longer daylengths than southern populations. CPP is genetically based, but also adapts over time responding to the population's environment.Therefore, CPP has been shown to lengthen with increasing latitude and altitude. While the positive correlation between CPP and latitude/altitude has been established in a few mosquito species, including Aedes albopictus (Skuse, Diptera: Culicidae), Aedes triseriatus, Aedes sierrensis, and Wyeomyia smithii (Coquillett, Diptera: Culicidae), we do not know when most other species initiate their seasonal responses. As several of these species transmit important diseases, characterizing the CPP of arthropod vectors could improve existing control by ensuring that surveillance efforts align with the vector's seasonally active period. Additionally, better understanding when mosquitoes and other vectors initiate diapause can reduce the frequency of chemical applications, thereby ameliorating the negative impacts to nontarget insects.

Mosquito surveillance data can be used for predicting mosquito distribution and dynamics as they relate to human disease. Often these data are collected by independent agencies and aggregated to state and national level portals to characterize broad spatial and temporal dynamics. These larger repositories may also share the data for use in mosquito and/or disease prediction and forecasting models. Assumed, but not always confirmed, is consistency of data across agencies. Subtle differences in reporting may be important for development and the eventual interpretation of predictive models. Using mosquito vector surveillance data from Arizona as a case study, we found differences among agencies in how trapping practices were reported. Inconsistencies in reporting may interfere with quantitative comparisons if the user has only cursory familiarity with mosquito surveillance data. Some inconsistencies can be overcome if they are explicit in the metadata while others may yield biased estimates if they are not changed in how data are recorded. Sharing of metadata and collaboration between modelers and vector control agencies is necessary for improving the quality of the estimations. Efforts to improve sharing, displaying, and comparing vector data from multiple agencies are underway, but existing data must be used with caution.

The bed bug, Cimex lectularius L., is a common ectoparasite found to live among its vertebrate hosts. Antennal segments in bugs are critical for sensing multiple cues in the environment for survival.To determine whether the thermo receptors of bed bugs are located on their antennae; innovative bioassays were created to observe the choice between heated and unheated stimuli and to characterize the response of bugs to a heat source. Additionally, the effect of complete antenectomized segments on heat detection were evaluated. Heat, carbon dioxide, and moisture are cues that are found to activate bed bug behavior; a temperature at 38°C was used to assess the direction/degree at which the insect reacts to the change in distance from said stimulus. Using a lightweight spherical ball suspended by air through a vacuum tube, bed bugs and other insects are able to move in 360° while on a stationary point. Noldus EthoVision XT was used to capture video images and to track the bed bugs during 5-min bioassays. A bioassay was created using four Petri dish arenas to observe bed bug attraction to heat based on antennae segments at 40°C.The purpose of this study was to evaluate the effects of heat on complete antenectomized segments of the antennae.The results in this experiment suggest that bed bugs detect and are attracted to heat modulated by nutritional status. Learning the involvement of antennae segments in heat detection will help identify the location and role of thermoreceptors for bed bug host interaction.

Many insects use photoperiod as a signal to anticipate upcoming unfavorable conditions. Photoperiod sensitivity may be a relevant factor in Aedes (Stegomyia) aegypti (L.) populations at the cool margins of the species' range, where winter conditions have a strong effect on population dynamics. In this study, we evaluated the effect of parental photoperiod on preimaginal survival and developmental time, and on wing length for the first generation of Ae. aegypti from a temperate region (Buenos Aires City, Argentina). Our experiment started with eggs from parents exposed to short-day (SD; 10:14 [L:D]) or long-day (LD; 14:10 [L:D]) photoperiods during their entire life span. Eggs were stored under the same photoperiod (SD or LD) as their parents for 91 d, until immersion. After hatching, larvae were reared until adult emergence in thermal baths at one of two constant temperatures (17 or 23°C), at a photoperiod of 12:12 (L:D) h and fed ad libitum. Survival from larva I to adult emergence was not affected either by parental photoperiod or rearing temperature. At a rearing temperature of 23°C, female offspring from the SD parental photoperiod developed faster and had shorter wings compared with those from the LD parental photoperiod. No effect of parental photoperiod was observed on female offspring reared at 17°C. In male offspring, parental photoperiod had no effect on developmental time and wing length, independently of the rearing temperature. Results indicate that the parental photoperiod may affect some offspring traits. This effect may be a characteristic of Ae. aegypti populations in temperate regions to deal with the winter conditions.

Holometabolous insects undergo complete metamorphosis, and hence, they have different phases of development (egg, larva, pupa, and adult), which occupy distinct ecological niches. The pupae of several fly species are surrounded by the puparium, which is a rigid structure, usually formed by the integument of the last larval instar. The puparium presents unique characteristics distinct from those of the larval and adult phases. During intrapuparial development, it is possible to distinguish at least four fundamental and continuous steps, namely: 1) larval–pupal apolysis, 2) cryptocephalic pupa, 3) phanerocephalic pupa, and 4) pharate adult. The objective of this work was to describe the external morphology of the distinct phase of development for five species that were collected, identified, and raised in the laboratory; intrapuparial development was studied by fixing immature specimens at regular intervals; the morphological analyses were performed with the aid of both light and scanning electron microscopy. Under the conditions established (27 ± 1.0 or 23 ± 1.0°C, 60 ± 10% relative humidity, 12 h of photoperiod), the minimum time for intrapuparial development was: 252 h for Megaselia scalaris (Loew 1966) (Phoridae), 192 h for Piophila casei (Linnaeus 1758) (Piophilidae), Fannia pusio (Wiedemann 1830) (Fanniidae), and Musca domestica (Linnaeus 1758) (Muscidae), and 96 h for Chrysomya megacephala (Fabricius 1794) (Calliphoridae). Intrapuparial development has defined steps, and distinct species responded differently to the same environmental conditions. In addition, it is possible to establish a sequential rule without ignoring the specific characteristics of each taxon.

A basic tenet of forensic entomology is development data of an insect can be used to predict the time of colonization (TOC) by insect specimens collected from remains, and this prediction is related to the time of death and/or time of placement (TOP). However, few datasets have been evaluated to determine their accuracy or precision. The black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae) is recognized as an insect of forensic importance. This study examined the accuracy and precision of several development datasets for the black soldier fly by estimating the TOP of five sets of human and three sets of swine remains in San Marcos and College Station, TX, respectively. Data generated from this study indicate only one of these datasets consistently (time-to-prepupae 52%; time-to-eclosion 75%) produced TOP estimations that occurred within a day of the actual TOP of the remains. It is unknown if the precolonization interval (PreCI) of this species is long, but it has been observed that the species can colonize within 6 d after death. This assumption remains untested by validation studies. Accounting for this PreCI improved accuracy for the time-to-prepupae group, but reduced accuracy in the time-to-eclosion group. The findings presented here highlight a need for detailed, forensic-based development data for the black soldier fly that can reliably and accurately be used in casework. Finally, this study outlines the need for a basic understanding of the timing of resource utilization (i.e., duration of the PreCI) for forensically relevant taxa so that reasonable corrections may be made to TOC as related to minimum postmortem interval (mPMI) estimates.

Foraging by Calliphora vicina Robineau-Desvoidy often leads to a period of bubbling behavior, followed by either deposition of the regurgitate onto surfaces or reuptake of the bubble. Eventually, the partially or undigested food is passed in the excreta forming fecal or defecatory stains on surfaces in which deposition occurs. This study examined the digestive artifacts (i.e., regurgitate and defecatory stains) formed following consumption of human blood and semen by adult flies in an attempt to determine the length of time the meal was retained in the crop. The morphological appearance of either type of stain appeared consistent with the color of blood or semen for 10–20 d after feeding. When tested with ABA Hematrace immunochromatographic strip assays, blood was detectable in at least 33% of fly artifacts 25 d after the initial consumption of blood. Similarly, semen was detected in nearly 34% of digestive artifacts 30 d after feeding on human semen when using ABA p30 cards. Human body fluids were also detected in fly artifacts when using RSID lateral flow assays, but a much lower percentage of artifacts tested positive for blood (4.9%) and semen (4.6%) 25-d postfeeding in comparison to ABA strip assays. The difference between the types of lateral flow assays appeared to be due to extraction efficiencies of the buffers used for isolation of blood or semen from the fly artifacts. The implications of these observations in reference to seasonal adaptations and to bloodstain pattern analysis at crime scenes are discussed.

Chrysomya rufifacies (Macquart), the hairy maggot blow fly, is of great importance for the field of forensic entomology due to its habit as an early colonizer of decomposing vertebrate remains and myiasis producer. Development studies on this species have been conducted in scattered regions of the world, using types of tissue from several species of animals as a rearing medium. Despite the commonality of C. rufifacies in Sri Lanka, developmental studies have never been performed in this region. As well, the effects of diet on development have not been tested. In the current study, C. rufifacies immatures were reared on skeletal muscle, liver, and heart from domestic swine, with flies from colonies maintained at 25 and 28°C.The minimum time needed to complete each stage at 25°C on liver (224.14 h) was fastest followed by skeletal muscle (249.33 h) and heart (251.64 h) respectively, whereas at 28°C, fly development was quickest on heart muscle (178.27 h) followed by liver (178.50 h) and skeletal muscle (186.17 h) respectively. A significant difference in total development time was determined for temperature, while the rearing medium was not significant. Temperature also showed a significant effect on the length and the width of the larvae, while the type of tissue statistically impacted only the width.

Lyme disease is the most common tick-borne disease in North America. Though human infection is mostly transmitted in a limited geography, the range has expanded in recent years. One notable area of recent expansion is in the mountainous region of southwestern Virginia. The ecological factors that facilitate or constrain the range of human Lyme disease in this region remain uncertain. To evaluate this further, we obtained ecological data, including remotely sensed data on forest structure and vegetation, weather data, and elevation. These data were aggregated within the census block groups of a 9,153 km² area around the cities of Blacksburg and Roanoke, VA, an area with heterogeneous Lyme disease transmission. In this geographic area, 755 individuals were reported to have Lyme disease in the 10 yr from 2006 to 2015, and these cases were aggregated by block group. A zero-inflated negative binomial model was used to evaluate which environmental variables influenced the abundance of Lyme disease cases. Higher elevation and higher vegetation density had the greatest effect size on the abundance of Lyme disease. Measures of forest edge, forest integrity, temperature, and humidity were not associated with Lyme disease cases. Future southward expansion of Lyme disease into the southeastern states may be most likely in ecologically similar mountainous areas.

Approximately 80 species of mosquitoes (Diptera: Culicidae) have been documented in Canada. Exotic species such as Aedes albopictus (Skuse) (Diptera: Culicidae) are becoming established. Recently occurring endemic mosquito-borne diseases (MBD) in Canada including West-Nile virus (WNV) and Eastern Equine Encephalitis (EEE) are having significant public health impacts. Here we explore the use of DNA metabarcoding to identify mosquitoes from CDC light-trap collections from two locations in eastern Canada.Two primer pairs (BF2-BR2 and F230) were used to amplify regions of the cytochrome c oxidase subunit I (CO1) gene. High throughput sequencing was conducted using an Illumina MiSeq platform and GenBank-based species identification was applied using a QIIME 1.9 bioinformatics pipeline. From a site in southeastern Ontario, Canada, 26 CDC light trap collections of 72 to >300 individual mosquitoes were used to explore the capacity of DNA metabarcoding to identify and quantify captured mosquitoes. The DNA metabarcoding method identified 33 species overall while 24 species were identified by key. Using replicates from each trap, the dried biomass needed to identify the majority of species was determined to be 76 mg (equivalent to approximately 72 mosquitoes), and at least two replicates from the dried biomass would be needed to reliably detect the majority of species in collections of 144–215 mosquitoes and three replicates would be advised for collections with >215 mosquitoes.This study supports the use of DNA metabarcoding as a mosquito surveillance tool in Canada which can help identify the emergence of new mosquito-borne disease potential threats.

Madagascar has an important diversity of fleas (Siphonaptera), which almost species do not exist elsewhere. Scientists have provided huge efforts to improve knowledge on Malagasy fleas since the middle of 1900s particularly by investigating topics such as taxonomy, systematics, biogeography, and flea vector role. Since then, new species discovery has increased and currently, 48 species are recorded which the majority is endemic.Therefore, it becomes necessary to have updated keys to identify species membership.This paper presents morphological-based keys to identify at genus and species levels adult fleas reported as occurring in Madagascar. Illustrations are proposed to make easier the observation of morphological criteria, which may be tricky for sibling species.

The genus Serratacarus , currently includes only two species, Serratacarus dietzi Goff and Whitaker, 1994 and Serratacarus lasiurus Goff and Whitaker, 1994, which were recorded on cricetid rodents from natural reserve areas of Brazil. Here, we provide a review of the morphological characters for both species and synonymize of the species Trombewingia brasiliensis with S. lasiurus. Additionally, we provide new locality records for both species and the first record for S. dietzi on southeastern four-eyed opossum, Philander frenatus Olfers, 1818 (Didelphimorphia, Didelphidae).

Chigger mites are parasites of terrestrial vertebrates, including humans. Here, we describe two new species belonging to the American genera Colicus Brennan and Parasecia Loomis. Both species were described on the base of museum specimens originated from Minas Gerais State, Brazil, Colicus barrosbattestiae n. sp. parasitizing the rodent, Oligoryzomys fornesi and Parasecia jacinaviciusi n. sp. parasitizing the marsupial, Monodelphis domestica.

The distribution of Aedes aegypti (L.) (Diptera: Culicidae) is expanding towards colder regions, which could be aided by an adaptation of the immature stages to the local thermal conditions. This study aimed to assess the developmental success at different temperatures in three populations of Ae. aegypti located across a climate gradient in Argentina. Survival to the adult stage, development time, and wing length at 14, 18.5 and 24°C were compared among three populations of Argentina: Resistencia in the subtropical region, and Buenos Aires and San Bernardo in the temperate region. Survival was similar between populations and equal to or higher than 69%, and increased at higher temperatures within the studied range. Development times were similar between populations. A negative effect of temperature was observed and the reduction of development time at increasing temperatures was stronger for males than for females. Wing lengths were negatively affected by increasing temperatures, and the reduction of wing length was stronger for females than for males. Also, the reduction of wing lengths with temperature was stronger for San Bernardo and Resistencia than for Buenos Aires, and differences between sexes were larger for Resistencia than for Buenos Aires or San Bernardo. Although the results do not evidence differences in survival and development time between temperate and tropical populations, the three populations have a higher tolerance to low temperatures than the populations from other regions.

Flea infestations of wild rabbits were examined monthly in central Spain in a meso-Mediterranean area for 5 yr. A total of 1,180 wild rabbits were trapped and 7,022 fleas were collected from them. Overall, the prevalence was 74.1% with a mean flea index of 5.95 fleas per rabbit. Four flea species were identified: Spilopsyllus cuniculi (Dale, 1878) was the most abundant species (accounting for 74.3% of fleas collected) followed by Xenopsylla cunicularis (Smit, 1957), Odontopsyllus quirosi (Gil Collado, 1934), and Nosopsyllus fasciatus (Bosc, 1800) (18.9, 6.7, and 0.1%, respectively).The highest prevalence was observed in S. cuniculi (48.6%) followed by X. cunicularis, O. quirosi, and N. fasciatus (34.3, 20.0, and 0.6%, respectively). Odontopsyllus quirosi and S. cuniculi were mainly collected from autumn to spring with the peak of infestation in winter, while X. cunicularis was mainly found from spring to autumn with maximum levels of infestation during the summer months.The relevance of these findings is discussed.

The geographic distribution of the Rocky Mountain wood tick, Dermacentor andersoni Stiles, was determined in Alberta, Canada, by drag sampling at 86 and 89 sites during 2011 and 2012, respectively. Tick density and prevalence varied between years, averaging (range) 1.0 (0–26.2) and 5.9 (0–110) ticks/1,000 m² in 2011 and 2012, respectively. Ticks were detected at 24.4% and 42.7% of the sites sampled in each respective year. Tick density and presence declined in a northerly direction to 51.6°N and in a westerly direction to ca. 113°W, except for a small area of high density at the edge of the Rocky Mountains in the southeastern portion of the province. Ticks were most abundant in the Dry Mixedgrass and Montane natural subregions and in areas with Brown Chernozemic, Regosol, and Solodized Solonetzic great soil groups. A logistic regression model indicated that tick presence was increased in the Dry Mixedgrass natural subregion and in regions with greater temperatures during the previous summer and normal winter precipitation but was reduced in areas with Dark Brown Chernozemic soils. The model will be useful for predicting tick presence and the associated risk of tick-borne diseases in the province.

Yellow fever is an endemic disease in America caused by an arbovirus that circulates in the sylvatic cycle between nonhuman primates and mosquitoes of the genera Sabethes Robineau-Desvoidy and Haemagogus Williston.The main goal of this work is to report the distribution patterns of these genera in Argentina through an updated database built from published records as well as from own sample collections. These genera are represented in Argentina by a total of 18 species distributed in 14 provinces and 10 ecoregions. The ecoregions with greatest biodiversity were Paranense Forest, Yungas, Campos and Malezales. This database will also allow generating distribution maps for these mosquito genera, and their respective species in Argentina, to establish areas with high probability of viral circulation that are an essential input for vector surveillance, as a tool for public health decision-makers.

Entomopathogenic fungi such as Beauveria bassiana (Balsamo) Vuillemin and Metarhizium anisopliae/brunneum (Metchnikoff)/Petch have shown promising results for managing the house fly, Musca domestica L. A primary challenge of using these biological control agents (BCAs) in field situations is the time required to induce high adult house fly mortality, typically 6–7 d post-exposure. In this study, virulence of M. anisopliae (strain F52) and four B. bassiana strains were compared. The B. bassiana strains GHA and HF23 are used in commercial products and those were compared with two strains that were isolated from house flies on dairy farms (NFH10 and L90). Assays were conducted by exposing adult house flies to fungal-treated filter paper disks for 2 h.The lethal time to 50% mortality (LT₅₀) at the high concentration of 1 × 10⁹ conidia ranged from 3.8 to 5.2 d for all five strains. GHA, NFH10, and L90 killed flies faster than M. anisopliae strain F52; HF23 did not differ from either the M. anisopliae or the other B. bassiana strains. Attempts with the NFH10 strain to induce faster fly mortality through selection across 10 fungal to fly passages did not result in shorter time to fly death of the selected strain compared with the unselected strain.

Flonicamid is a chordotonal modulator and novel systemic insecticide that has been used frequently for controlling a broad range of insect pests.The risk of flonicamid resistance was assessed through laboratory selection and determining inheritance pattern and cross-resistance potential to five insecticides in house fly, Musca domestica L. Very low to high flonicamid resistance in M. domestica populations was found compared with the susceptible strain (SS). A flonicamid-selected (Flonica-RS) M. domestica strain developed 57.73-fold resistance to flonicamid screened for 20 generations compared with the SS. Overlapping 95% fiducial limits of LC₅₀ of the F₁ and F₁ ^ǂ, and dominance values (0.87 for F₁ and 0.92 for F₁ ^ǂ) revealed an autosomal and incomplete dominant flonicamid resistance.The monogenic model of resistance inheritance suggested a polygenic flonicamid resistance.The Flonica-RS strain displayed negative cross-resistance between flonicamid and sulfoxaflor (0.10-fold) or clothianidin (0.50-fold), and very low cross-resistance between flonicamid and flubendiamide (4.71-fold), spinetoram (4.68-fold), or thiamethoxam (2.02-fold) in comparison with the field population. The estimated realized heritability (h²) value of flonicamid resistance was 0.02. With selection mortality 40–90%, the generations required for a 10-fold increase in LC₅₀ of flonicamid were 94–258 at h² (0.02) and slope (3.29). Flonicamid resistance was inherited as autosomal, incomplete dominant, and polygenic in the Flonica-RS. Negative or very low cross-resistance between flonicamid and sulfoxaflor, clothianidin, flubendiamide, spinetoram, and thiamethoxam means that these insecticides can be used as alternatives for controlling M. domestica.These data can be useful in devising the management for M. domestica.

This study reports the first baseline information on tropical bed bug, Cimex hemipterus (F.) (Hemiptera: Cimicidae), infestations in Ghana.The purpose of this study was to assess bed bug infestation levels, and the efficacy of locally available insecticides and long-lasting insecticidal nets (LLINs) in controlling field bed bugs populations in the Cape Coast region. A survey was undertaken to assess bed bug infestation levels and current control practices by residents. In total, 205 bed bug affected households were identified in 20 communities and live bed bug infestations were associated with most of these premises. Many homeowners knew of other households (from 1 to 3) with a bed bug infestation. Residents reported itching and swelling of the skin from the bed bug bites and the bites were considered severe.The most common household bed bug control strategy was the application of insecticides. However, LLINs and commercially formulated insecticides commonly used by households (notably chloropyrifos and pyrethroid-based formulations) did not efficaciously suppress field collected strains of C. hemipterus. Using a dipping bioassay, mean mortality ranged from 0 to 60% for eggs, nymphs, and adults, and less than 40% mortality was observed in bed bugs placed on insecticide-treated filter paper. Each LLINs (all are pyrethroid based) produced a mean mortality of less than 20% in adult bed bugs. For a more effective response to the global bed bug resurgence in developing countries, government and supporting agencies need to render assistance to bed bug affected residents through the provision of improved pest management strategies.

Cimex lectularius L. populations have been documented worldwide to be resistant to pyrethroids and neonicotinoids, insecticides that have been widely used to control bed bugs. There is an urgent need to discover new active ingredients with different modes of action to control bed bug populations. Fipronil, a phenylpyrazole that targets the GABA receptor, has been shown to be highly effective on bed bugs. However, because fipronil shares the same target site with dieldrin, we investigated the potential of fipronil resistance in bed bugs. Resistance ratios in eight North American populations and one European population ranged from 1.4- to >985-fold, with highly resistant populations on both continents. We evaluated metabolic resistance mechanisms mediated by cytochrome P450s, esterases, carboxylesterases, and glutathione S-transferases using synergists and a combination of synergists. All four detoxification enzyme classes play significant but variable roles in bed bug resistance to fipronil. Suppression of P450s and esterases with synergists eliminated resistance to fipronil in highly resistant bed bugs. Target-site insensitivity was evaluated by sequencing a fragment of the Rdl gene to detect the A302S mutation, known to confer resistance to dieldrin and fipronil in other species. All nine populations were homozygous for the wild-type genotype (susceptible phenotype). Highly resistant populations were also highly resistant to deltamethrin, suggesting that metabolic enzymes that are responsible for pyrethroid detoxification might also metabolize fipronil. It is imperative to understand the origins of fipronil resistance in the development or adoption of new active ingredients and implementation of integrated pest management programs.

From 2008 to 2017, the city of Abidjan, Côte d'Ivoire experienced several Aedes-borne disease epidemics which required control of the vector mosquito population based on the reduction of larval habitats and insecticidal sprays for adult mosquitoes.This study was undertaken to assess the insecticide susceptibility status of Aedes aegypti (Linnaeus) in the city of Abidjan. Immature Ae. aegypti were sampled from several larval habitats within seven communes of Abidjan and reared to adults.Three to five days old F1 emerged adults were tested for susceptibility using insecticide-impregnated papers and the synergist piperonyl butoxide (PBO) following WHO bioassay guidelines. The results showed that Ae. aegypti populations from Abidjan were resistant to 0.1% propoxur, and 1% fenitrothion, with mortality rates ranging from 0% to 54.2%. Reduced susceptibility (93.4–97.5% mortality) was observed to 0.05% deltamethrin, 0.75% permethrin, 0.05% lambda-cyhalothrin, 5% malathion, and 0.8% chlorpyrifos-methyl. This reduced susceptibility varied depending on the insecticide and the collection site. The restoration of mortality when the mosquitoes were pre-exposed to the synergist PBO suggests that increased activity of oxidases could be contributing to resistance. Three kdr mutations (V410L, V1016I, and F1534C) were present in populations tested, with low frequencies for the Leu410 (0.28) and Ile1016 (0.32) alleles and high frequencies for the Cys1534 allele (0.96). These findings will be used to inform future arbovirus vector control activities in Abidjan.

We conducted a baseline characterization of the abundance and seasonality of Aedes aegypti (Linnaeus, 1762)—a vector of dengue, chikungunya, and Zika—in two suburban localities of Yucatan, Mexico, as the first step in the implementation of an integrated vector management (IVM) plan combining ‘traditional Aedes control’ (source reduction/truck-mounted ultra-low volume [ULV] spraying) and incompatible insect technique/sterile insect technique for population suppression in Yucatan, Mexico. Weekly entomological collections with ovitraps and BG-sentinel traps were performed in 1-ha quadrants of both localities for 1 yr. Three distinct periods/phases were identified, closely associated with precipitation: 1) a phase of low population abundance during the dry season (weekly average of Aedes eggs per ovitrap and adults per BG trap = 15.51 ± 0.71 and 10.07 ± 0.88, respectively); 2) a phase of population growth and greatest abundance of Aedes (49.03 ± 1.48 eggs and 25.69 ± 1.31 adults) during the rainy season; and finally 3) a phase of decline among populations (20.91 ± 0.97 eggs and 3.24 ± 0.21 adults) after the peak of the rainy season. Seasonal abundance and dynamics of Ae. aegypti populations suggest that it is feasible to develop and implement time-specific actions as part of an IVM approach incorporating integrating novel technologies (such as rear-and-release of Wolbachia-infected males) with classic (insecticide-based) approaches implemented routinely for vector control. In agreement with the local vector control program, we propose a pilot IVM strategy structured in a preparation phase, an attack phase with traditional vector control, and a suppression phase with inundative releases, which are described in this paper.

European guidelines for testing attractant and repellent efficacy (i.e., Product type 19 [PT19]) have been in revision since 2017. A key topic of discussion is the current approach to evaluating topical repellents. The European Chemical Agency has stated field testing should be avoided because of mosquito-borne disease risks. However, the most common laboratory method, the arm-in-cage (AIC) test, may limit the reliable extrapolation of lab results to field conditions.This study's main goal was to assess alternative laboratory methods for evaluating topical mosquito repellents that use mosquito landing rates more representative of those in the field.The study took place at three European testing labs using 30 study participants per test and the mosquito, Aedes albopictus (Skuse, 1894, Diptera: Culicidae). In phase 1, a conventional AIC test and a sleeved AIC test were performed. Respectively, the arm area exposed was 600 and 100 cm², and cage volume was 0.040 and 0.064 m³. Mosquito density was the same for both: 1 female/840 cm³. In phase 2, room-based testing (40 ± 5 mosquitoes in 25–30 m³) was used as a proxy for field testing.The mosquito repellent employed was 15% N,N-diethyl-m-toluamide in ethanol at two doses: 1 and 0.5 g/600 cm².The protection times measured at each laboratory were analyzed both separately and together using nonparametric (Kruskal–Wallis) test. The two alternatives methods showed to be potential alternatives to the current AIC method recreated field mosquito landing rates and achieved reproducible protection times across laboratories.

Graphical abstract

Gene mutations on target sites can be a valuable indicator of the status of insecticide resistance. Jeddah, a global commercial and major port-of-entry city, is bearing the brunt of dengue disease burden in Saudi Arabia. In the current study, six genotypes of three codon combinations (989, 1016, and 1534) were observed on voltage-gated sodium channel (VGSC) gene in Jeddah's Aedes aegypti population, with PGF/PGC as the dominant one.Two types of introns between exon 20 and 21 on VGSC have been identified for the first time in Ae. aegypti in Saudi Arabia. Statistical and phylogenetic analyses showed that the intron type was significantly associated with the 1016 allele and may reflect the history of insecticide treatment in different continents. In addition, fixation of the L1014F allele on VGSC and G119S on acetylcholinesterase 1 gene was detected in local Culex quinquefasciatus populations, with frequencies of 95.24 and 100%, respectively.To the best of our knowledge, this is the first report of resistant-associated mutations in field-caught Cx. quinquefasciatus in Saudi Arabia.The high prevalence of insecticide resistance gene mutations in local primary mosquito vector species highlights the urgent need to carry out comprehensive insecticide resistance surveillance in Saudi Arabia.

In Illinois, between 1990 and 2017, tick-borne diseases in humans increased 10-fold, yet we have insufficient information on when and where people are exposed to vector ticks (Ixodida: Ixodidae).The aims of our research were to compare contributions of passive and active tick collection methods in determining establishment of ticks of public health concern and obtain information on tick distributions within Illinois.We used three surveillance strategies within the IllinoisTick Inventory Collaboration Network to gather information about the ticks of public health concern: 1) passive collection (voluntary submission by the public); 2) systematic collection (biweekly active surveillance); and 3) special collections (active collections in locations of special interest). Of collected adult and nymphal ticks, 436 were from passive collections, 142 from systematic collections, and 1,270 from special collections.Tick species distribution status changed in 36 counties. Our data provide noteworthy updates to distribution maps for use by public health agencies to develop prevention and control strategies. Additionally, the program built a network of collaborations and partnerships to support future tick surveillance efforts within Illinois and highlighted how the combination of the three surveillance strategies can be used to determine geographic spread of ticks, pinpoint locations in need of more surveillance, and help with long-term efforts that support phenology studies.

This study was conducted to determine the influence of environmental factors on the prevalence of house dust mites in student dormitories of Bandar Abbas city. In this study, 64 dust samples were collected from seven randomly selected dormitories located in various areas of the Bandar Abbas.The collected mites were isolated and mounted in Hoyer's medium and identified using a morphological key.The associations between the environmental factors and the density of house dust mites were investigated. In total, 1,093 adult mites were collected and identified.They consisted of four species including Dermatophagoides pteronyssinusTrouessart (57.6%), Dermatophagoides farinae Hughes (24.3%) and Dermatophagoides evansi Fain (14.9%) (Acari: Pyroglyphidae), and Cheyletus malaccensis Oudemans (3.2%) (Acari: Cheyletidae). All of the dormitories were contaminated by more than one house dust mites species and the mean density of house dust mites in dormitories was 8.3 ± 0.2 mites/g of dust. There was a significant relationship between average house dust mites density and some of environmental factors such as relative humidity, temperature, floor covering type, and number of occupants (P < 0.05). Results of this study revealed that two major allergenic dust mites, D. pteronyssinus and D. farinae, were the most prevalent and collected from all of dormitories and some of indoor environmental factors found to influence mites' population.

Anopheles mosquitoes are the main vectors of malaria. There is little information on the current entomological aspects of Anopheles mosquitoes in Amhara region of northwestern Ethiopia. Therefore, the aim of this study was to assess the prevailing species composition, parous rate, and infection rate of Anopheles mosquitoes in the Bahir Dar city administration. A community-based cross-sectional study was conducted from January through July 2020. For this, six Centers for Disease Control and Prevention light traps (three traps indoor and three traps outdoor) were used to collect adult female Anopheles mosquitoes. The species were morphologically identified, and the parous and infection rates were determined via dissection of ovaries and salivary gland, respectively. A total of 378 adult female Anopheles mosquitoes comprised of three species (Anopheles d'thali, Anopheles rhodesiensis, and Anopheles gambiae complex) were collected and identified at the study sites. Anopheles rhodesiensis was the predominant species accounting for 90% of all collections at the Zenzelima site, followed by An. gambiae complex (6.5%). In contrast, An. gambiae complex was the predominant species at theTis Abay site, comprising 94% of captures.The overall parous and infection rates were 35 (62.5%) and 1 (2.9%), respectively.

In California, the western blacklegged tick, Ixodes pacificus Cooley and Kohls, is the principal vector of the Borrelia burgdorferi sensu lato (sl) complex (Spirochaetales: Spirochaetaceae, Johnson et al.), which includes the causative agent of Lyme disease (B. burgdorferi sensu stricto). Ixodes pacificus nymphs were sampled from 2015 to 2017 at one Sierra Nevada foothill site to evaluate our efficiency in collecting this life stage, characterize nymphal seasonality, and identify environmental factors affecting their abundance and infection with B. burgdorferi sl.To assess sampling success, we compared the density and prevalence of I. pacificus nymphs flagged from four questing substrates (logs, rocks, tree trunks, leaf litter). Habitat characteristics (e.g., canopy cover, tree species) were recorded for each sample, and temperature and relative humidity were measured hourly at one location. Generalized linear mixed models were used to assess environmental factors associated with I. pacificus abundance and B. burgdorferi sl infection. In total, 2,033 substrates were sampled, resulting in the collection of 742 I. pacificus nymphs. Seasonal abundance of nymphs was bimodal with peak activity occurring from late March through April and a secondary peak in June. Substrate type, collection year, month, and canopy cover were all significant predictors of nymphal density and prevalence. Logs, rocks, and tree trunks had significantly greater nymphal densities and prevalences than leaf litter. Cumulative annual vapor pressure deficit was the only significant climatic predictor of overall nymphal I. pacificus density and prevalence. No associations were observed between the presence of B. burgdorferi sl in nymphs and environmental variables.

Borrelia burgdorferi, the spirochete that causes Lyme disease, is endemic and widespread in Wisconsin. Research in the northeastern United States has revealed a positive association between Babesia microti, the main pathogen that causes babesiosis in humans, and Bo. burgdorferi in humans and in ticks. This study was conducted to examine associations between the disease agents in the Upper midwestern United States. Ixodes scapularis Say nymphs (N = 2,858) collected between 2015 and 2017 from nine locations in Wisconsin were tested for Babesia spp. and Borrelia spp. using real-time PCR.Two species of Babesia were detected; Ba. microti and Babesia odocoilei (a parasite of members of the family Cervidae). Prevalence of infection at the nine locations ranged from 0 to 13% for Ba. microti, 11 to 31% for Bo. burgdorferi sensu stricto, and 5.7 to 26% for Ba. odocoilei. Coinfection of nymphs with Bo. burgdorferi and Ba. odocoilei was detected in eight of the nine locations and significant positive associations were observed in two of the eight locations.The prevalence of nymphal coinfection with both and Bo. burgdorferi and Ba. microti ranged from 0.81 to 6.5%. These two pathogens were significantly positively associated in one of the five locations where both pathogens were detected. In the other four locations, the observed prevalence of coinfection was higher than expected in all but one site-year. Clinics and healthcare providers should be aware of the association between Ba. microti and Bo. burgdorferi pathogens when treating patients who report tick bites.

Microorganisms living in the midgut of Anopheles mosquitoes have been studied to fight vector-borne diseases, such as malaria. Studies on the microbiota of the Neotropical Anopheles darlingi, the most important Brazilian vector for malaria, have been reported for the same purpose. Our aims were to isolate and identify culturable bacteria from An. darlingi mosquito guts through their feces and to estimate the species richness and the frequency distribution of the sampled bacteria. Sixty wild females of An. darlingi mosquitoes were captured at two rural locations, near Porto Velho, Rondônia, Brazil. Bacteria were isolated from mosquito feces, which were collected using cages which permit the collection of feces on LB nutrient agar plates. Sixty bacterial colonies were isolated and stored in glycerol at –80°C. Bacteria were identified by sequencing their 16S rRNA gene obtained using PCR and Sanger sequencing. To aid in species identification, MALDI-TOF, VITEK2, and BBL Crystal were used as complementary protocols.The sequences obtained from the 60 bacterial isolates were compared to sequences deposited in GenBank (NCBI) using BLAST. Homology greater than 97% between the query and the subject was used as the criteria for assigning the identity of each isolate. Fourteen species from eight different genera were identified among the 60 isolates. The most frequent species were Serratia liquefaciens (20%) and Serratia marcescens (15%). Due to their established apathogenicity and according to previous studies, we suggest Serratia and Pantoea species as suitable for paratransgenesis development to fight malaria in Brazilian Amazon.

The vector competence of mosquitoes for pathogens has been shown to be influenced by the status of insecticide resistance in the mosquito population. However, to date, only two studies has explored the impact of insecticide resistance on arbovirus transmission. The global and widespread use of pyrethroids has led to the development of insecticide resistance in many mosquito species, including Aedes aegypti (Linnaeus) (Diptera: Culicidae), the primary vector of Zika virus. Strains of Ae. aegypti that were genetically similar, but responded differently to pyrethroid exposure, were developed using backcrossing techniques. These populations were orally infected with Zika virus and susceptibility to infection, disseminated infection, and transmission potential were evaluated. Analyses revealed differences in susceptibility to infection and disseminated infection between the pyrethroid susceptible and resistant strains of Ae. aegypti during the infection period. Here, we identify an additional challenge to that of widespread pyrethroid resistance. Specifically, resistance is associated with altered phenotypic traits that influence susceptibility to arbovirus infection and progression of infection in the mosquito, factors which ultimately influence risk of arbovirus transmission. These findings support the need to 1) consider insecticide resistance status during times of arbovirus transmission and 2) to implement insecticide resistance management/mitigation strategies in vector control programs.

Studies on experimental sand fly infection require the availability of colonies and laboratory conditions. In Brazil, Lutzomyia longipalpis (Diptera: Psychodidae) (Lutz and Neiva 1912) is responsible for the highest infection rates by Leishmania spp. and this species is one of the most suitable species for laboratory colonization. In this study, we describe a method for growing Lu. longipalpis in laboratory conditions (10 generations) from natural populations sampled from a region of high endemicity for visceral leishmaniasis in the state of Maranhão, Northeastern Brazil. Using two methods (individualized or grouped females), the colony's highest productivity occurred in the first four generations, where all stages presented with high frequency. Nonviable eggs represented more than 50% of the total eggs produced by engorged females, while pupae were more resistant to fungal contamination, with a mortality rate of only 2%. In both methods, there was a predominance of female emergence; however, the ratio between males and females did not show significant differences, IF (P = 0.8023) and GF (P = 0.1831). Using the method of individualized females, the F4 generation took the longest to appear (234 d; 64 ± 57 d); by grouped females, F3 took the longest to appear (102 d; 47 ± 20 d). This method provides sufficient numbers of insects to perform vector competence tests for Leishmania spp. that cause the cutaneous form of leishmaniasis, usually found in Lu. longipalpis sampled from the study location.

Graphical Abstract

The relapsing fever spirochetes Borrelia hermsii and Borrelia turicatae are each maintained and transmitted in nature by their specific tick vectors, Ornithodoros hermsi Wheeler (Acari: Argasidae) and Ornithodoros turicata (Duges), respectively. The basis for this spirochete and vector specificity is not known, but persistent colonization of spirochetes in the tick's salivary glands is presumed to be essential for transmission by these long-lived ticks that feed in only minutes on their warm-blooded hosts. To examine this hypothesis further, cohorts of O. hermsi and O. turicata were infected with B. hermsii and examined 7–260 d later for infection in their midgut, salivary glands, and synganglion. While the midgut from all ticks of both species at all time points examined were infected with spirochetes, the salivary glands of only O. hermsi remained persistently infected. The salivary glands of O. turicata were susceptible to an early transient infection. However, no spirochetes were observed in these tissues beyond the first 32 d after acquisition. Ticks of both species were fed on mice 112 d after they acquired spirochetes and only those mice fed upon by O. hermsi became infected. Thus, the vector competency for B. hermsii displayed by O. hermsi but not O. turicata lies, in part, in the persistent infection of the salivary glands of the former but not the latter species of tick. The genetic and biochemical mechanisms supporting this spirochete and vector specificity remain to be identified.

Sand fly larvae develop in sheltered humid habitats containing decaying organic matter on which they feed. Previously, we showed that gravid females of Phlebotomus papatasi Scopoli (Diptera: Psychodidae) are attracted to and stimulated to lay eggs on larval rearing medium containing larvae. That study, however, did not control for the possible effect of medium aging. Our goal in this study was to evaluate the effect of larval substrate conditioning on attraction and oviposition responses of Ph. papatasi sand flies while controlling for the effect of substrate aging. Initially, we confirmed that the pretreatment fresh larval food sources (to be used as larval conditioned and unconditioned media) did not differ with respect to their effect on attraction and oviposition responses. The larval conditioned medium was produced by rearing larvae to the second/third-instar stage over 3 wk using the same larval food source. To produce larval unconditioned medium, the same amount of fresh larval food was added to a control rearing cup that did not contain larvae but was aged under identical time and conditions. Two-choice bioassays were conducted to evaluate gravid female's attraction and oviposition response to larval conditioned and unconditioned media. We found that gravid females were significantly attracted (P < 0.05) to larval conditioned medium when compared with unconditioned medium under the same amount of time and conditions. However, no such difference was found with respect to oviposition response. Both attraction and oviposition responses were significantly increased for larval conditioned and unconditioned media in comparison to the initial fresh larval food source.

Two individuals of the jaguar, Panthera onca (L.), were captured near the municipality of Presidente Figueiredo, Brazilian Amazon, during the years of 2017 and 2018. The jaguars presented furuncular myiasis caused by the human botfly Dermatobia hominis (L.) on the rear thighs and tail. This is the first record of infestation of D. hominis in P. onca in the Amazon region.

Adult females and males of Ixodes affinis and Ixodes scapularis are illustrated by focus stacking image photography, and morphological character states are described that reliably differentiate the two species. In conjunction with other environmental cues, such as the questing phenology of adults, these characteristics will enable the rapid identification of adults of either sex along the southern Coastal Plain of the United States, where these species are sympatric.

SARS-CoV-2 is a recently emerged, highly contagious virus and the cause of the current COVID-19 pandemic. It is a zoonotic virus, although its animal origin is not clear yet. Person-to-person transmission occurs by inhalation of infected droplets and aerosols, or by direct contact with contaminated fomites. Arthropods transmit numerous viral, parasitic, and bacterial diseases; however, the potential role of arthropods in SARS-CoV-2 transmission is not fully understood. Thus far, a few studies have demonstrated that SARS-CoV-2 replication is not supported in cells from certain insect species nor in certain species of mosquitoes after intrathoracic inoculation. In this study, we expanded the work of SARS-CoV-2 susceptibility to biting insects after ingesting a SARS-CoV-2-infected bloodmeal. Species tested included Culicoides sonorensis (Wirth & Jones) (Diptera: Ceratopogonidae) biting midges, as well as Culex tarsalis (Coquillett) and Culex quinquefasciatus (Say) mosquitoes (Diptera: Culicidae), all known biological vectors for numerous RNA viruses. Arthropods were allowed to feed on SARS-CoV-2-spiked blood and at a time point postinfection analyzed for the presence of viral RNA and infectious virus. Additionally, cell lines derived from C. sonorensis (W8a), Aedes aegypti (Linnaeus) (Diptera: Culicidae) (C6/36), Cx. quinquefasciatus (HSU), and Cx. tarsalis (CxTrR2) were tested for SARS-CoV-2 susceptibility. Our results indicate that none of the biting insects, nor the insect cell lines evaluated support SARS-CoV-2 replication, suggesting that these species are unable to be biological vectors of SARS-CoV-2.

Studies of the geographic distribution of sand flies and the factors associated with their occurrence are necessary to understand the risk of leishmaniasis transmission. The objective of this study was to characterize the sand fly fauna, particularly the spatial distribution of Lutzomyia longipalpis (Lutz & Neiva), and correlate these with climate factors in the Dourados municipality, Brazil. The collection of sand flies was carried out with CDC LightTraps over two periods: at six sites for three consecutive nights each month from August 2012 to July 2013; and at four other sites for two consecutive nights each month from April 2017 to February 2018. We collected 591 sand flies in the first period and 121 in the second period for a total of 712 sand flies; 697 of the total collected were Lu. longipalpis. The minimum and maximum sand fly infestation rate (sites with vector presence) was 11.1% and 83.33% in the first period, and 0% and 50.0% in the second period. No sand flies with Leishmania were identified via PCR. Lu. longipalpis presented an aggregate disposition with excellent adjustment. Rainfall and relative humidity were the abiotic factors that influenced the vector infestation level. The aggregate distribution for this species was predicted by the environmental factors that favor the proliferation of Lu. longipalpis. The results of this study should assist in devising measures to control sand flies in Dourados, Brazil.

Native to the Eastern United States and Eastern Canada, Aedes triseriatus (eastern tree hole mosquito) is an important vector of La Crosse virus and dog heartworm. Although its range has been well characterized in the United States, few studies have surveyed its distribution within Canada. In this study, mosquitoes were collected from a variety of urban and rural communities throughout Manitoba, Canada between the years of 2018 and 2020. Aedes triseriatus was identified and confirmed molecularly to be present in 13 communities. This includes localities that expand the species known distribution to new northern and western areas, and suggests that past surveillance efforts have not been comprehensive or environmental factors have caused this mosquito species to be present in areas in which it was not found previously. As Canada is showing signs of a changing climate, this may be driving the broader occurrence of Ae. triseriatus.

In October 2020, three captive male white-tailed deer, Odocoileus virginianus [Zimmermann] (artiodactyla: Cervidae), were found dead in central Pennsylvania and a fourth was euthanized due to extreme lethargy. The deer presented with high burdens of Dermacentor albipictus (Packard) (Ixoda: Ixodidae) (winter tick). There were no other clinical symptoms and deer were in otherwise good physical condition with no observed alopecia. Winter tick epizootics have been associated with mortalities of moose, Alces alces [Linnaeus] (artiodactyla: cervidae), and more recently elk, Cervus canadensis [Erxleben] (artiodactyla: cervidae), in Pennsylvania, but have not been reported in white-tailed deer. Mild winters are favorable to winter ticks and deer producers and managers should be aware of possible infestations as a result.

Pesticide resistance in medically significant disease vectors can negatively impact the efficacy of control efforts. Resistance research on ticks has focused primarily on species of veterinary significance that experience relatively high degrees of control pressure. Resistance in tick vectors of medical significance has received little attention, in part because area-wide pesticide applications are not used to control these generalist tick species. One of the few effective methods currently used for area-wide control of medically important ticks, including Ixodes scapularis Say (Acari: Ixodidae), is deployment of 4-poster devices. Deer self-apply a topical acaricide (permethrin) while feeding on corn from the devices. A 4-poster program using permethrin has been deployed on Shelter Island, NY to control I. scapularis populations since 2008. We collected engorged female ticks from deer in this management area and a location in the Mid-Hudson River Valley, NY without area-wide tick control. Larvae were reared from egg masses and their susceptibility to permethrin was tested. Larvae originating from a long-term laboratory colony were used as a susceptible baseline for comparison. Compared against the laboratory colony, resistance ratios at LC-50 for Shelter Island and Hudson Valley I. scapularis were 1.87 and 1.51, respectively.The susceptibilities of the field populations to permethrin were significantly lower than that of the colony ticks. We provide the first data using the larval packet test to establish baseline susceptibility for I. scapularis to permethrin along with information relevant to understanding resistance emergence in tick populations under sustained control pressure from 4-poster devices.

Haemaphysalis longicornis Neumann, Asian longhorned tick, was collected in Madison County, Kentucky, United States as part of an ongoing collaborative-tick surveillance project.This is the first collection of this invasive tick that includes ancillary data on habitat and landscape features derived from the USDA Forest Service, Forest Inventory and Analysis program.