Multiple factors lead to extensive variation in mosquito and mosquito-borne virus control programs throughout the United States. This variation is related to differences in budgets, number of personnel, operational activities targeting nuisance or vector species, integration of Geographical Information Systems, and the degree of research and development to improve management interventions through collaboration with academic institutions. To highlight this heterogeneity, the current study evaluates associations among the size of a mosquito control community, the research productivity, and the mosquito-borne virus human disease burden among states within the continental United States. I used the attendance at state mosquito and vector control meetings as a proxy for the size of the mosquito control community in each state. To judge research productivity, I used all peer-reviewed publications on mosquitoes and mosquito-borne viruses using data originating in each state over a 5- and 20-yr period. Total neuroinvasive human disease cases caused by mosquito-borne viruses were aggregated for each state. These data were compared directly and after adjusting for differences in human population size for each state. Results revealed that mean meeting attendance was positively correlated with the number of publications in each state, but not after correcting for the size of the population in each state. Additionally, human disease cases were positively correlated with the number of publications in each state. Finally, mean meeting attendance and human disease cases were only marginally positively associated, and no correlation existed after correcting for human population size. These analyses indicated that the mosquito control community size, research productivity, and mosquito-borne viral human disease burden varied greatly among states. The mechanisms resulting in this variation were discussed and the consequences of this variation are important given the constantly changing environment due to invasive mosquito species and arboviruses, urbanization, immigration, global travel, and climate change.

Cattle and sheep can develop immunity to paralysis caused by Dermacentor andersoni Stiles; however, this has been reported only in animals that were initially challenged with a high dose of ticks and exhibited clear symptoms of paralysis. Paralysis in sheep occurs in a dose-dependent fashion, with no paralysis occurring in sheep exposed to <0.2 ticks per kilogram sheep weight, and 100% paralysis in sheep exposed to >0.8 ticks per kilogram. This experiment was conducted to determine if sheep exposed to a low dose of ticks would also develop immunity to paralysis. Sheep were exposed to either a low (0.2 ticks per kilogram) or high dose of ticks (0.8 ticks per kilogram), then re-exposed to a second challenge of a paralyzing dose of ticks. All naïve sheep (eight of the eight) were paralyzed, while paralysis occurred in only four of the eight sheep previously exposed to a low dose, and one of the eight sheep previously exposed to a high dose. Results indicate that immunity can develop when sheep are exposed to a subclinical dose of paralyzing ticks, but in a smaller percentage of animals than those exposed to a high dose of ticks. Vaccine development perhaps remains the best option for nonacaricidal control of tick paralysis.

The southern cattle tick, Rhipicephalus (Boophilus) microplus (Canestrini), is the most economically important cattle ectoparasite in the world. Rhipicephalus microplus and Rhipicephalus annulatus (Say) continue to threaten U.S. cattle producers despite eradication and an importation barrier based on inspection, dipping of imported cattle in organophosphate (OP) acaricide, and quarantine of infested premises. OP acaricides inhibit acetylcholinesterase (AChE), essential to tick central nervous system function. Unlike vertebrates, ticks possess at least three genes encoding AChEs, differing in amino acid sequence and biochemical properties. Genomic analyses of R. microplus and the related tick, Ixodes scapularis, suggest that ticks contain many genes encoding different AChEs. This work is the first report of a salivary cholinesterase (ChE) activity in R. microplus, and discusses complexity of the cholinergic system in ticks and significance of tick salivary ChE at the tick–host interface. It further provides three hypotheses that the salivary ChE plausibly functions 1) to reduce presence of potentially toxic acetylcholine present in the large bloodmeal imbibed during rapid engorgement, 2) to modulate the immune response (innate and/or acquired) of the host to tick antigens, and 3) to influence transmission and establishment of pathogens within the host animal. Ticks are vectors for a greater number and variety of pathogens than any other parasite, and are second only to mosquitoes (owing to malaria) as vectors of serious human disease. Saliva-assisted transmission (SAT) of pathogens is well-known; however, the salivary components participating in the SAT process remain to be elucidated.

Dengue virus (DENV) is transmitted by Aedes spp mosquitoes during a bloodmeal uptake. The bloodmeal consists of host cells, immune factors, and possibly blood-borne pathogens, such as arboviruses. Human cells and immune-related factors, like the complement system, can remain active in the bloodmeal and may be able to interact with pathogens in the mosquito. Previous studies have shown that active complement proteins impact Plasmodium parasite viability in the Anopheles midgut. Thus, we investigated the effects of the human complement on DENV infection in the midgut of Aedes aegypti. Our findings indicate that mosquitoes receiving DENV mixed with normal non-inactivated human serum showed significantly lower viremia than those fed with heat-inactivated serum. This implies that human complement may act to limit DENV infection in the mosquito midgut. In addition, we found that human complement C5a protein was able to directly communicate with mosquito cells, affecting the cell antiviral response against DENV. Our results also show that human C5a protein is able to interact with several membrane-bound mosquito proteins. Together these results suggest an important role of human complement protein in DENV transmission.

This study was conducted to investigate the relationship between the number of house dust mites/g dust and different physical and environmental variables. A total of 1,040 house dust samples were collected from houses in Bitlis and Muş Provinces, Turkey, between May 2010 and February 2012. Overall, 751 (72.2%) of dust samples were mite positive. The number of mites/g dust varied between 20 and 1,840 in mite-positive houses. A significant correlation was detected between mean number of mites and altitude of houses, frequency of monthly vacuum cleaning, number of individuals in the household, and relative humidity. No association was found between the number of mites and temperature, type of heating, existence of allergic diseases, age and structure of houses. A maximum number of mites were detected in summer and a minimum number was detected in autumn.

The scuttle fly, Megaselia scalaris (Loew) (Diptera: Phoridae), is of medical, veterinary, and forensic importance. In the case of the latter, M. scalaris is commonly associated with indoor death or neglect cases of humans or household animals, and its larvae are useful in determining time of colonization (TOC). This study is the first to examine the effects of different temperatures and tissues from two vertebrate species on the growth rate and larval length of M. scalaris. A preliminary validation of these data was also conducted. Immatures of M. scalaris were reared on either bovine or porcine biceps femoris at 24 °C, 28 °C, and 32 °C. Temperature significantly impacted immature development time, including egg eclosion, eclosion to pupation, and pupation to adult emergence, to favor faster development at higher temperatures. From ovipostion to eclosion, development rate was 32.1% faster from 24 °C to 28 °C, 13.9% faster from 28 °C to 32 °C, and 45.5% faster from 24 °C to 32 °C. Development from eclosion to pupation displayed similar results with differences of 30.3% between 24 °C and 28 °C, 15.4% between 28 °C and 32 °C, and 45.2% between 24 °C and 32 °C. Development from pupation to adult emergence, likewise, displayed a 44.4% difference from 24 °C and 28 °C, 7.3% from 28 °C to 32 °C, and 51.2% from 24 °C to 32 °C. From oviposition to adult emergence, M. scalaris needed ∼32.7% more hours to complete development when reared at 24 °C than 28 °C, 8.5% when reared at 28 °C rather than 32 °C, and 38.4% more time when reared at 24 °C over 32 °C. Tissue type did not significantly impact development.

A preliminary validation study was conducted in four indoor environments (two attics, a closet, and a bathroom) spanning two different buildings. Utilizing minimum and mean lengths, time of colonization estimates were underestimated in all instances. The predicted range encompassed the actual TOC for two of the four environments. On average, when using minimum length, time of colonization was underestimated by 45%, but overestimated by only 2% when using maximum development range. Data generated from this research could be useful when estimating a TOC of decomposing vertebrate remains. Future research will need to examine development for each stadium in order to increase precision of such estimates.

West Nile virus (WNV) and Flanders virus (FLAV) can cocirculate in Culex mosquitoes in parts of North America. A large dataset of mosquito pools tested for WNV and FLAV was queried to understand the spatiotemporal relationship between these two viruses in Shelby County, TN. We found strong evidence of global clustering (i.e., spatial autocorrelation) and overlapping of local clustering (i.e., Hot Spots based on Getis Ord Gi*) of maximum likelihood estimates (MLE) of infection rates (IR) during 2008–2013. Temporally, FLAV emerges and peaks on average 10.2 wk prior to WNV based on IR. Higher levels of WNV IR were detected within 3,000 m of FLAV-positive pool buffers than outside these buffers.

The adult female of the sand fly species Martinsmyia minasensis (Mangabeira, 1942) is described, and the characters of the genus MartinsmyiaGalati, 1995 are defined. We performed morphometric analyses on the spermatheca and wings, and present data on the geographical distribution of M. minasensis, as well as an identification key to females of this genus. The specimens were measured, drawn, photographed, and compared with the similar species M. oliveirai. It was possible to distinguish between M. minasensis and M. oliveirai based on differences found in the common and individual ducts of the spermatheca, as well as wing shape and size.

A new stivaliid flea genus, Musserellus, and five new species are described. The new genus is compared with its closest morphological relatives, the genera Rectidigitus Holland and Metastivalius Holland. Musserellus vanpeeneni sp. nov., Musserellus wattsi sp. nov., Musserellus whitei sp. nov., and Musserellus marshalli sp. nov. are described from endemic murid rodents in Sulawesi, Indonesia, while Musserellus dunneti sp. nov. is described from Rattus rattus in West Papua, Indonesia. Host associations and the biogeographical relevance of the faunal connection between Sulawesi and New Guinea shown by Musserellus are briefly discussed.

The pruritic skin disease scabies is caused by the burrowing of the itch mite Sarcoptes scabiei (De Geer). It is difficult to diagnose this disease because its symptoms often resemble those of other skin diseases. No reliable blood or molecular diagnostic test is available. The aim of this project was to begin to characterize the scabies proteome to identify scabies mite proteins, including those that may be useful in the development of a diagnostic test or vaccine. Various scabies mite extracts were separated by two-dimensional electrophoresis, and 844 Coomassie Blue-stained protein spots were excised, subjected to trypsin digestion, and analyzed by Matrix Assisted Laser Desorption/Ionization Time-Of-Flight/Time-Of-Flight (MALDI-TOF/TOF) mass spectrometry (MS). Tryptic fragment sequences determined by MS were searched against the recently completed S. scabiei annotated genome, leading to the identification of >150 proteins. Only 10 proteins hit to previously identified scabies proteins including actin, tropomyosin, and several ABC transporters. Thirteen proteins had homology to dust mite allergens (members of groups 8, 10, 13, 17, 20, 25, and 28). Most other sequences showed some homology to proteins in other mites and ticks including homologs of calmodulin, calreticulin, lipocalin, and glutathione-Stransferase. These data will now allow the identification of the proteins to which scabies patients produce antibodies, including those that may be good candidates for inclusion in a diagnostic test and vaccine.

Ammonium and sulfide in water of tree hole and tire habitats of Aedes triseriatus Say larvae could accumulate to toxic levels, limiting growth and production of larvae and adults. Both ions were detected in water samples taken in longitudinal series over 11 dates from 10 habitats of each type during the larval growth season, at concentrations suggestive of reducing conditions in these habitats. Ammonium was more concentrated overall in water of both habitat types, while sulfide was more concentrated in tires than in tree holes. Water of tree holes was more acidic, whereas water in tires tended to be more basic, an important difference relative to the tendency of ammonium to form the more toxic ammonia moiety under basic conditions. Oxygen saturation was low in both habitat types, indicative of hypoxic conditions such that aerobic respiration would be limited. First-and fourth-instar larvae were sensitive to ammonium and sulfide in acute dose-response assays, but LC₅₀ values were above maximum concentrations observed under field conditions, suggesting that toxic effects of ammonium and sulfide on larvae are not acute, but could be chronic.

The size and success of epidemiologically significant adult mosquito populations are inherently tied to the conditions of the aquatic habitat in which juvenile stages grow until eclosion. While resource competition and quality are well-established controls to juvenile growth and survival, the implications to overall population rates of increase are less understood due to the large sample sizes needed to parameterize population models for all five juvenile life stages under multiple environmental and demographic conditions. Here, we present the results of >4,300 trials of wild-caught Aedes triseriatus (Say, 1823) larvae and pupae reared under varying resource quantity crossed by the presence or absence of competition within a single cohort as well as multiple overlapping cohorts. Demographic projection was used to make predictions of the realized growth rates of simulated Ae. triseriatus populations across the range of potential Ae. triseriatus fecundity. Further, to inform control efforts on juvenile habitat, we constructed a stochastic simulation to estimate the rates of successful emergence from habitats under different resource regimes and levels of cohort overlap. We found that while Ae. triseriatus populations were robust to low resource levels and competition within a cohort, the combination of these stressors with multiple cohort overlap led to self-limitation or complete collapse of mosquito populations. Despite this importance of intraspecific competition to population viability, the stochastic simulation revealed only a modest self-limitation of adult emergence, with the clear implication that high-resource habitats are a higher value control target.

Comprehensive knowledge on vector dynamics is lacking in Botswana and yet essential for effective indoor residual spraying. This study assessed some of the entomological indices that contribute to malaria transmission by an indoor-resting population of Anopheles arabiensis Patton (Diptera: Culicidae) in Tubu village, Okavango subdistrict. The pyrethroid space-spray technique and hut searches were used to sample mosquitoes. Species and bloodmeal source identification were done using the polymerase chain reaction techniques. The infective status was determined by the enzyme-linked immuno-sorbent assay test. The human blood indices (HBI), human-biting rates (HBR), and vector densities were computed. Anopheles arabiensis was the sole vector and member of the Anopheles gambiae Giles complex identified. Significant changes in vector densities were observed over seasons, while nonsignificant differences were observed among the huts (P > 0.05). The main source of bloodmeal was cattle (46.8% [65]). There were no significant differences in HBI (P > 0.05) and HBR (P > 0.05) between the seasons. All the 271 mosquitoes tested for sporozoite infection were negative. The results showed that seasonal variations in vector densities corresponded to the traditional malaria and nonmalaria seasons. The vector population was relatively more zoophagic. The HBI and HBR were not influenced by the seasons. None of the endophilic mosquitoes tested (N = 271) was positive for sporozoites. Our study provided some relevant basic information to the local malaria control program that may be used to strategize their operations if malaria elimination has to be achieved by 2017.

A survey of reptile-associated ticks and their infection status with severe fever with thrombocytopenia syndrome (SFTS) virus was conducted to determine the relative abundance and distribution among lizards, skinks, and snakes in the Republic of Korea (ROK). In total, 132 reptiles, including 49 lizards (two species), 15 skinks (one species), and 68 snakes (eight species) were collected. In total, 84 ixodid ticks belonging to two genera (Ixodes and Amblyomma) were collected from 28/132 (21.2%) lizards, skinks, and snakes. Ixodes nipponensis Kitaoka & Saito was only collected from lizards and skinks, while Amblyomma testudinarium Koch was only collected from snakes. Takydromus wolteri had the highest tick index (0.7; total number ticks/total number collected hosts) among lizards and skinks, while Rhabdophis tigrinus had the highest tick index (2.2) among the snakes. Ixodes nipponensis larvae and nymphs accounted for 11.1% and 88.9%, respectively, of all ticks collected from lizards and skinks, while only A. testudinarium nymphs were collected from snakes. Nymphs of both species of ticks were collected from lizards and skinks from April to October, while I. nipponensis larvae were collected only from September to October. Ixodes nipponensis larvae and nymphs were preferentially attached to the lateral trunk (83.3%) and the foreleg axillae (16.7%) of lizards and skinks. SFTS virus was detected in both I. nipponensis and A. testudinarium collected from lizards and snakes. Phylogenetic analysis of SFTS viruses of ticks collected from two lizards and one snake demonstrated close relationships with SFTS virus strains observed from humans and ticks in the ROK, China, and Japan. These results implicate lizards and snakes as potential hosts of SFTS virus.

Cockroaches, insects of the order Blattodea, seem to play a crucial role in the possible conjugation-mediated genetic exchanges that occur among bacteria that harbor in the cockroach intestinal tract. The gut of these insects can be thought of as an effective in vivo model for the natural transfer of antimicrobial resistance plasmids among bacteria. In our study, we evaluated the conjugation-mediated horizontal transfer of resistance genes between Escherichia coli and other microorganisms of the same Enterobacteriaceae family within the intestinal tract of Blaberus craniifer Burmeister, 1838 (Blattodea: Blaberidae). Different in vivo mating experiments were performed using E. coli RP4 harboring the RP4 plasmid carrying ampicillin, kanamycin, and tetracycline resistance genes as the donor and E. coli K12 resistant to nalidixic acid or Salmonella enterica serovar Enteritidis IMM39 resistant to streptomycin as the recipients. The RP4 plasmid was successfully transferred to both recipients, producing E. coli K12-RP4 and S. Enteritidis IMM39-RP4 transconjugants. Conjugation frequencies in vivo were similar to those previously observed in vitro. The transfer of the RP4 plasmid in all transconjugants was confirmed by small-scale plasmid isolation and agar gel electrophoresis, suggesting that the intestinal tract of cockroaches is an effective in vivo model for natural gene transfer. Our results confirm that cockroaches allow for the exchange of antimicrobial resistance plasmids among bacteria and may represent a potential reservoir for the dissemination of antibiotic-resistant bacteria in different environments. These findings are particularly significant to human health in the context of health care settings such as hospitals.

Ixodes scapularis Say, the black-legged tick, is the primary vector in the eastern United States of several pathogens causing human diseases including Lyme disease, anaplasmosis, and babesiosis. Over the past two decades, I. scapularis-borne diseases have increased in incidence as well as geographic distribution. Lyme disease exists in two major foci in the United States, one encompassing northeastern states and the other in the Upper Midwest. Minnesota represents a state with an appreciable increase in counties reporting I. scapularis-borne illnesses, suggesting geographic expansion of vector populations in recent years. Recent tick distribution records support this assumption. Here, we used those records to create a fine resolution, subcounty-level distribution model for I. scapularis using variable response curves in addition to tests of variable importance. The model identified 19% of Minnesota as potentially suitable for establishment of the tick and indicated with high accuracy (AUC = 0.863) that the distribution is driven by land cover type, summer precipitation, maximum summer temperatures, and annual temperature variation. We provide updated records of established populations near the northwestern species range limit and present a model that increases our understanding of the potential distribution of I. scapularis in Minnesota.

During 2013, we collected and tested ticks for Heartland virus (HRTV), a recently described human pathogen in the genus Phlebovirus (Bunyaviridae), from six sites in northwestern Missouri. Five sites were properties owned by HRTV patients, and the sixth was a conservation area that yielded virus in ticks during 2012. We collected 39,096 ticks representing five species; however, two species, Amblyomma americanum (L.) (97.6%) and Dermacentor variabilis (Say) (2.3%), accounted for nearly all ticks collected. We detected 60 HRTV-positive tick pools and all were composed of A. americanum: 53 pools of nymphs, six pools of male adults, and one pool of female adults. This is the first record of HRTV in adult ticks. Virus was detected at five properties that yielded A. americanum ticks, including properties owned by four of five patients. Virus was detected at two sites that yielded virus in 2012. Detection of virus in multiple years indicates that the virus persists in ticks within a relatively small geographic area, although infection rates (IR) may vary greatly among sites and between years at a site. IR per 1,000 A. americanum in northwestern Missouri during the April–July 2013 study period were as follows: all adults, IR = 1.13; adult females, IR = 0.33; adult males, IR = 1.90; and nymphs, IR = 1.79. The IR in nymphs, the stage with the largest data set, corresponds to 1/559 infected ticks. Having robust estimates of IR in various stages for A. americanum should lead to more accurate public health messaging and a better understanding of virus transmission.

Aedes aegypti (L.) has become an efficient vector of important arboviruses due to its anthropophilic and domiciliary behaviors. Since the 1980s, dengue affects thousands of people every year in Brazil; in Fernando de Noronha (FN), a touristic archipelago, dengue cases have occurred since 2001. Once Ae. aegypti populations are well established in the inhabited areas of FN, the threat of dengue or another arbovirus epidemic is continuously imminent. This study aimed to monitor the DENV serotypes in mosquito samples collected in FN, where at least one resident was clinically diagnosed as dengue patient. Entomological surveillance was conducted in 2011 and 2012. Mosquitoes were sorted by sex and location and were stored in pools. DENV detection was performed using polymerase chain reaction with reverse transcription (RT-PCR) and the Platelia Dengue NS1 Ag. RNA integrity was checked by RT-PCR using rpL8 primers, and the minimum infection rate (MIR) was calculated. In total, 339 pools were analyzed, and only one was positive (DENV-1) by Multiplex RT-PCR (MIR = 1.53). When considering only pools with RNA integrity, the MIR was 2.92. Using the Platelia kit, the MIR was 9.18 (considering all the pools) and 17.54 (only 140 pools with RNA integrity). Our results showed the importance of a constant entomological surveillance in that area, the need to improve storage and transportation protocols, and an endogenous control in the RT-PCR to avoid false-negative results. Finally, our study indicated that the NS1-Ag detection was the most sensitive method and should be used routinely for DENV surveillance in mosquitoes if the serotype identification is not required.

Phlebotomus papatasi is one of the most medically important sand fly species in the Old World, serving as a vector of Leishmania parasites and phleboviruses. Chemical control is still considered the most effective method for rapidly reducing populations of flying insects involved in vector-borne disease transmission, but is increasingly threatened by insecticide resistance in the target insect posing significant problems for entomologists responsible for control programs. This study was conducted to determine pyrethroid resistance mechanisms and the biological, physiological, and molecular impacts of resistance in Ph. papatasi, and to compare their resistance mechanisms against those reported for mosquitoes and other intensely studied dipterans. Field-collected Ph. papatasi from Aswan, Egypt, were subjected to sublethal doses of permethrin and reared as a resistant strain under laboratory conditions through 16 generations. Biological parameter observations of resistant Ph. papatasi revealed an association of resistance with productivity cost. Physiological analysis revealed that concentrations of oxidase and esterase enzymes increased in early generations of the resistant colony, and then subsided through the F16 generation to levels similar to those in a susceptible colony. The activity levels of acetylcholinesterase were higher in field-collected Ph. papatasi than in susceptible colony flies, but decreased significantly despite subsequent exposure to permethrin. The molecular search for gene mutations in the resistant strain of Ph. papatasi failed to identify any mutations common in pyrethroid-resistant mosquitoes. Our study revealed that the mechanism of pyrethroid resistance in sand flies is different than that in mosquitoes, at least at the genetic level.

Insect growth regulators (IGRs) methoprene and pyriproxyfen are widely used as topical treatments to pets or applied to the indoor environment to control cat fleas, Ctenocephalides felis (Bouché). The toxicity of methoprene, pyriproxyfen, and combinations of both IGRs to cat flea larvae was determined. The LC₅₀ of methoprene and pyriproxyfen applied to larval rearing medium was 0.39 and 0.19 ppm, respectively. Combinations of methoprene:pyriproxyfen in ratios of 1:1, 5:1, 10:1, and 20:1 produced LC₅₀s of 0.06, 0.09, 0.19, and 0.13 ppm, respectively. The pyriproxyfen synergized the activity of methoprene as indicated by the combination indices (CI). The ratio of methoprene:pyriproxyfen (40:1) provided an LC₅₀ of 0.42 ppm and the pyriproxyfen was not synergistic. Combinations of pyriproxyfen:methoprene in ratios of 5:1, 10:1, and 20:1 provided LC₅₀s of 0.14, 0.20, 0.20 ppm, respectively, and the methoprene did not synergize the activity of pyriproxyfen. The dose-reduction indices (DRIs) indicated that the concentrations of IGRs in the combinations of methoprene:pyriproxyfen (ratios of 20:1 or less) could be reduced by at least one-third of the amount required by methoprene alone to provide similar larval mortality. Combinations of methoprene and pyriproxyfen may be effective in increasing the residual activity on pets and assist in reducing the likelihood of insecticide resistance developing to IGRs.

A study to evaluate the use of light-emitting diodes (LEDs) as an attractant for phlebotomine sand flies at two animal pens in a livestock area in Brazil was performed. Light-suction traps were operated overnight with the following light sources: green, blue, and incandescent (control) lights. In total, 22 individual collections were made at each site and 44 with each trap type. In total, 2,542 specimens belonging to 14 phlebotomine species were collected. The most abundant species in the light traps were Nyssomyia whitmani, Evandromyia evandroi, Micropygomyia goiana, Lutzomyia longipalpis, and Bichromomyia flaviscutellata. Taking the two sites together, the green-LED light was the most attractive, followed by the blue and incandescent lights, and the difference between the green-LED and the control was statistically significant. Most species were green-biased at both sites, but some species-specific differences were observed. However, even with these differences, the standard incandescent light was outcompeted by LEDs. The green-LED-biased response observed in the present study, together with numerous advantages in favor of LEDs, suggests that the green-LED light source can be used as an effective substitute for the currently used incandescent bulb in monitoring traps for phlebotomine sand flies in Brazil.

We examined bed bug prevalence in 2,372 low-income apartments within 43 buildings in four New Jersey cities using a combination of resident interviews, brief visual inspections, and monitoring with Climbup Insect Interceptors. Infestation rates ranged from 3.8 to 29.5% among the buildings, with an overall infestation rate of 12.3%. Within each apartment, the bed area trapped significantly more bed bugs per trap than the sofa (or upholstered chair) area. African American residents had a proportionally higher number of bed bug infestations than white residents. Women were more likely to report bed bug bite symptoms than men. Only 68% of the residents who experienced bed bug infestations reported symptoms after being bitten (n = 475). Among those with self-reported symptoms (n = 319), the frequency of the reported symptoms was: pain 90%, itchiness 20%, welts 13%, and insomnia 8%. Fifty-nine percent of the residents (n = 539) who experienced bed bug infestations applied insecticides to control bed bugs. Climbup interceptors detected 89 ± 1% and brief visual inspections detected 72 ± 3% of the infestations. Only two out of 291 infestations were not detected by brief visual inspection or interceptors. Assuming US$50 per hour labor rate, the average per apartment cost for the building-wide bed bug monitoring protocol was US$12 per apartment. Forty-nine percent of the infestations detected by the protocol were in apartments whose residents were unaware of the bed bug activity.

Aedes aegypti (L.) is a species of international concern because of its ability to transmit serious human arboviral diseases including yellow fever, dengue, and chikungunya, which have spread to all continents. Ovitraps are containers constructed to imitate Aedes’ natural breeding sites and have been used for many decades as a sensitive and inexpensive surveillance tool for detecting the presence of container-inhabiting mosquitoes. In addition to their value for vector surveillance, various ovitrap devices have been evaluated as tools for suppressing Ae. aegypti populations. In this study, we performed a biological and chemical characterization of a new ovitrap prototype manufactured by injection molding of low-density polyethylene (LDPE) with the larvicide pyriproxyfen. Our research shows that pyriproxyfen was immediately released from the LDPE into the water of the ovitrap and led to an emergence inhibition of 100% for over 30 weeks. In addition, ovitraps continued to show a high larvicidal activity after over 20 washes. Pyriproxyfen was detectable in the water after 20 s and reached a peak after 24 h. Our results show that this ovitrap can be an effective, inexpensive, and low-maintenance tool for Ae. aegypti surveillance and control.

Pediculosis is a prevalent parasitic infestation of humans, which is increasing due, in part, to the selection of lice resistant to either the pyrethrins or pyrethroid insecticides by the knockdown resistance (kdr) mechanism. To determine the extent and magnitude of the kdr-type mutations responsible for this resistance, lice were collected from 138 collection sites in 48 U.S. states from 22 July 2013 to 11 May 2015 and analyzed by quantitative sequencing. Previously published data were used for comparisons of the changes in the frequency of the kdr-type mutations over time. Mean percent resistance allele frequency (mean % RAF) values across the three mutation loci were determined from each collection site. The overall mean % RAF (±SD) for all analyzed lice was 98.3 ± 10%. 132/138 sites (95.6%) had a mean % RAF of 100%, five sites (3.7%) had intermediate values, and only a single site had no mutations (0.0%). Forty-two states (88%) had a mean % RAF of 100%. The frequencies of kdr-type mutations did not differ regardless of the human population size that the lice were collected from, indicating a uniformly high level of resistant alleles. The loss of efficacy of the Nix formulation (Prestige Brand, Tarrytown, NY) from 1998 to 2013 was correlated to the increase in kdr-type mutations. These data provide a plausible reason for the decrease in the effectiveness of permethrin in the Nix formulation, which is the parallel increase of kdr-type mutations in lice over time.

Several cases of human rickettsiosis caused by Rickettsia parkeri were recently documented in the Paraná River delta of Argentina, where the tick vector is Amblyomma triste Koch. As cattle suffer recurrent A. triste infestations, they are at risk of becoming infected with R. parkeri. Herein we investigated the dynamics of R. parkeri and its A. triste vector in a herd of beef cattle. Cattle were followed for 18mo and samples were analyzed for the presence of antibodies against four Rickettsia species (R. parkeri, Rickettsia bellii, Rickettsia amblyommii, and Rickettsia felis) and also for the presence of rickettsial DNA. Additionally, cattle were examined for attached ticks and questing adult ticks were collected. All ticks were analyzed for the presence of rickettsial DNA. No evidence of rickettsemia was found in any cow, but the high R. parkeri infection rate documented in A. triste both questing in the study area (13.9%) and feeding on cattle (19.8%) and the identification of antibodies against R. parkeri antigen in 90% of cattle are evidence that infection is taking place. Altogether, our data suggest that A. triste ticks are capable of naturally exposing cattle to R. parkeri. However, the progress of R. parkeri infection and its impact on bovine health and production remain to be established.

We assessed the prevalence of infection with Trypanosoma cruzi, parasite genotypes (discrete typing units, DTUs), and the host-feeding sources of domestic and peridomestic Triatoma infestans Klug and Triatoma eratyrusiformis Del Ponte in eight rural communities of the subandean Calchaqui valleys in northwestern Argentina. We sought to analyze their epidemiological role in the context of routine vector surveillance and control actions. Infection with T. cruzi was determined by optic microscopy or polymerase chain reaction (PCR) amplification of the hypervariable region of kinetoplast DNA minicircles. Parasite genotypes were identified through a multi PCR-based strategy. Bloodmeal contents were tested with a direct ELISA assay against nine antisera. Human sleeping quarters (domiciles) and peridomestic dry-shrub fences concentrated most of the T. infestans and T. eratyrusiformis infected with T. cruzi, respectively. The most frequent host-feeding sources of T. infestans were chickens (73.1%) in peridomiciles and humans (73.3%) in domiciles, whereas T. eratyrusiformis fed more often on cavid rodents (92.6%), which thrived in the dry-shrub fences. The main T. cruzi DTU identified in both vectors was T. cruzi I (TcI). Triatoma eratyrusiformis was implicated in the local circulation of TcI among cavies and perhaps mice, but infection with other typically domestic DTUs (TcVI and TcII/TcV/TcVI) indicated overlap between (peri)domestic transmission cycles in both vector species. Because dry-shrub fences were not targeted for routine insecticide spraying, they may act as sources of (peri)domestic reinfestation. Triatoma eratyrusiformis is an emergent secondary vector of T. cruzi and plays a significant role in the local transmission of T. cruzi.

Unblocked fleas can transmit Yersinia pestis, the bacterium that causes plague, shortly (≤4 d) after taking an infectious bloodmeal. Investigators have measured so-called early-phase transmission (EPT) efficiency in various fleas following infection with highly bacteremic blood (≥10⁸ cfu/ml). To date, no one has determined the lower limit of bacteremia required for fleas to acquire and transmit infection by EPT, though knowing this threshold is central to determining the length of time a host may be infectious to feeding fleas. Here, we evaluate the ability of Oropsylla montana (Baker) to acquire and transmit Y. pestis after feeding on blood containing 10³ to 10⁹ cfu/ ml. We evaluated the resulting infection prevalence, bacterial loads, and transmission efficiency within the early-phase time period at 1 d postinfection. Fleas acquired infection from bacteremic blood across a wide range of concentrations, but transmission was observed only when fleas ingested highly bacteremic blood.

West Nile virus (WNV) is an important cause of disease in humans and animals. Risk of WNV infection varies seasonally, with the greatest risk during the warmest parts of the year due in part to the accelerated extrinsic incubation rate of the virus in mosquitoes. Rates of extrinsic incubation have been shown in constant-temperature studies to increase as an approximately linear function of temperature, but for other vector-borne pathogens, such as malaria or dengue virus, nonlinear relationships have been demonstrated under cycling temperatures near the thermal limits of pathogen replication. Using typical daily air temperature profiles from three key periods of WNV amplification in a hyperendemic area of WNV activity in California's Central Valley, as well as a fourth temperature profile based on exposures that would result from daily mosquito host-seeking and resting behavior, we explored the impacts of cycling temperatures on WNV transmission by Culex tarsalis Coquillett, one of the principal vectors in the western United States. The daily cycling temperature ranges studied were representative of those that occur across much of California, but they did not significantly alter the extrinsic incubation period of WNV compared with estimates from mean temperatures alone. This suggests that within the relatively broad range we studied, WNV incubation rates are a simple function of mean temperature. Realistic daily temperature patterns that reflected mosquitoes' avoidance of daytime high temperatures during summer reduced transmission over time compared with air temperatures, indicating that adjustment for mosquito exposure temperatures would be prudent for calculating risk.

No licensed vaccine or antiviral drug against dengue virus (DENV) is available; therefore, most of the effort to prevent this disease is focused on reducing vector–host interactions. One of the most widely accepted methods of blocking vector–human contact is to use insect repellents to interfere with mosquito host-seeking behavior. Some arboviruses can replicate in the nervous system of the vector, raising the concern that arboviral infection may alter the insect behavioral response toward chemical stimuli. Three different Aedes aegypti (L.) mosquito cohorts: DENV-1-injected, diluent-injected, and uninjected were subjected to behavioral tests using a high-throughput screening system with 2.5% DEET and 0.14% DEET on 1, 4, 7, 10, 14, and 17 d postinjection. All test cohorts exhibited significant contact irritant or escape responses when they were exposed to 2.5% or 0.14% DEET. However, we found no biologically relevant irritancy response change in DENV-1-infected Ae. aegypti mosquitoes when they were exposed to DEET. Further studies evaluating the effects of other arboviral infections on insect repellents activity are necessary in order to provide better recommendation on the prevention of vector-borne disease transmission.

Nondestructive techniques allow the isolation of genomic DNA, without damaging the morphological features of the specimens. Though such techniques are available for numerous insect groups, they have not been applied to any member of the medically important families of mosquitoes (Diptera: Culicidae) and phlebotomine sand flies (Diptera: Psychodidae). This study presents Mild-Vectolysis, the first nondestructive DNA extraction methodology for vouchering taxa of mosquitoes and sand flies, which provided sufficient amounts of DNA, tested in a verified barcode (cytochrome oxidase I gene), while preserving their morphological integrity. Application of the method to sand flies allowed successful insect identification post DNA extraction, as all basic taxonomical structures necessary for identification (pharynx, cybarium, and genitalia) remained intact. The development of the methodology was more challenging in mosquitoes, due to the fragility of key morphological characters (scales and color). A small modification of the lysis buffer concentration, in combination with the adjustment of the incubation time, a postlysis freezing stage, and the avoidance of ethanol, achieved the extraction of sufficient DNA quantity, while preserving the integument of the mosquitoes, although a small proportion of the scales and the color still appeared to have been lost. In addition to the practicality and efficiency of our methodology, preserving of the original insect specimen post DNA extraction is highly advantageous, as it allows for 1) utilization of the specimen for further analysis and 2) storage for vouchering.

Panola Mountain Ehrlichia (PME) has been suggested as an emerging pathogen of humans and dogs. Domestic goats and white-tailed deer (Odocoileus virginianus) are also susceptible and likely serve as reservoirs. Experimentally, both the lone star tick (Amblyomma americanum (L.)) and the Gulf Coast tick (Amblyomma maculatum Koch) can transmit PME among deer and goats. In the current study, we detected PME in adult wild-caught A. maculatum from the United States and Amblyomma variegatum (F.) from the Caribbean and Africa. This significantly expands the range, potential tick vectors, and risk for exposure to PME.

Emerging and re-emerging vector-borne diseases such as chikungunya and dengue and associated Aedes vectors are expanding their historical ranges; thus, there is a need for the development of novel insecticides for use in vector control programs. The mosquito toxicity of a novel insecticide and repellent consisting of mediumchain carbon fatty acids (C8910) was examined. Determination of LC₅₀ and LC₉₀ was made against colonyreared Aedes aegypti (L.) and Aedes albopictus (Skuse) using probit analysis on mortality data generated by Centers for Disease Control and Prevention bottle bioassays. Six different concentrations of C8910 + silicone oil yielded an LC₅₀ of 160.3 µg a.i/bottle (147.6–182.7) and LC₉₀ of 282.8 (233.2–394.2) in Ae. aegypti; five concentrations yielded an LC₅₀ of 125.4 (116.1–137.6) and LC₉₀ of 192.5 (165.0–278.9) in Ae. albopictus. Further development of C8910 and similar compounds could provide vector control specialists novel insecticides for controlling insect disease vectors.

Horn flies, Haematobia irritans (L.), were photographed on cattle and then immediately estimated visually in the field on pastured beef cattle in southern California. Horn flies were counted in the pictures later on a computer screen. For 479 counts on individual cattle, the concordance correlation coefficient between the visual and photo-based assessments was 0.790, but was better for the higher half of the counts (0.732) than for the lower half of the counts (0.217). Major axis regression indicated that visual estimates were consistently higher than the number of flies counted in the pictures across the entire density range. Based on average raw means, the visual estimates averaged 21% higher than the photo counts. Visual estimates included flies on the belly and lower legs that could not be seen in a photo, and lower densities may have been more susceptible to such error. Where flies can be seen well, e.g. for very tame animals, the visual estimates were much faster and more costefficient and were sufficient to track relative horn fly abundance changes.

Peridomestic (“backyard”) chicken flocks are gaining popularity in the developed world (e.g., North America or Europe), yet little is known regarding prevalence or severity of their ectoparasites. Therefore, five birds on each of 20 properties throughout southern California were surveyed in summer for on-host (permanent) and off-host dwelling (temporary) ectoparasites. Only four premises (20%) were entirely free of ectoparasites. In declining order of prevalence (% of premises), permanent ectoparasites included six chicken louse species: Menacanthus stramineus (Nitzsch) (50%), Goniocotes gallinae (De Geer) (35%), Lipeurus caponis (L.) (20%), Menopon gallinae (L.) (15%), Menacanthus cornutus (Schömmer) (5%), and Cuclotogaster heterographus (Nitzsch) (5%). Only one flea species, Echidnophaga gallinacea (Westwood) (20%), was found. Three parasitic mite species were observed: Ornithonyssus sylviarum (Canestrini & Fanzago) (15%), Knemidocoptes mutans (Robin & Lanquetin) (10%), and Dermanyssus gallinae (De Geer) (5%). Many infestations consisted of a few to a dozen individuals per bird, but M. stramineus, G. gallinae, M. cornutus, and E. gallinacea were abundant (dozens to hundreds of individuals) on some birds, and damage by K. mutans was severe on two premises. Off-host dwelling ectoparasites were rare (D. gallinae) or absent (Cimex lectularius L., Argasidae). Parasite diversity in peridomestic flocks greatly exceeds that is routinely observed on commercial chicken flocks and highlights a need for increased biosecurity and development of ectoparasite control options for homeowners.

Morphological variations were observed in specimens of the sand fly species Sergentomyia bailyi Sinton 1931 collected from Pondicherry Union Territory, India. Examination of morphological characteristics showed differences in the length of sensilla chaeticum on antennal flagellomere 3 (A3) in males and females, in the size and shape of the spermathecae in females, and in the position of accessory spines on the gonostyle of males. In our previous study, DNA barcoding characterization of this sand fly species collected from Pondicherry UT revealed molecular variations within the S. bailyi population. This study confirms the existence of a species complex within S. bailyi population at Pondicherry UT.

Phlebotomine sand flies from three counties in Liberia were collected from January 2011 to July 2013. In total, 3,118 sand flies were collected: 18 species were identified, 13 of which represented new records for Liberia. An updated taxonomic checklist is provided with a brief note on sand fly biology, and the disease vector potential for species is discussed.

Due to an increasing diversity of bacterial pathogens known to be transmitted by hard ticks (Acari: Ixodidae) in North America, a comprehensive assay is needed to detect and differentiate among these numerous tick-borne pathogens. We describe an expanded protocol using a combination of multiplex polymerase chain reaction and reverse line blot hybridization to detect a greater diversity of infectious agents than were previously detectable. Ten novel oligonucleotide probes, either individually or in concert, enabled or enhanced identification of six Borrelia species, three Rickettsia species, and one Ehrlichia species. Simultaneous detection of these numerous tick-borne pathogens can advance surveillance efforts and improve accuracy of detection and, thus, reporting.

The rapid increase of bed bug populations resistant to pyrethroids demands the development of novel control tactics. Products combining pyrethroids and neonicotinoids have become very popular for bed bug control in the United States, but there are concerns about evolution of resistance to these compounds. Laboratory assays were used to measure the toxicity of topical applications of four neonicotinoids to a susceptible population and three pyrethroid-resistant populations. Activity of esterases, glutathione S-transferases, and cytochrome P450s of all strains was also evaluated. High levels of resistance to four neonicotinoids, acetamiprid, imidacloprid, dinotefuran, and thiamethoxam, relative to the susceptible Fort Dix population, were detected in populations collected from human dwellings in Cincinnati and Michigan. Because activity of detoxifying enzymes was increased in these two populations, our results suggest that these enzymes have some involvement in neonicotinoid resistance, but other resistance mechanisms might be involved as well. Detection of high levels of resistance to neonicotinoids further limits the options for chemical control of bed bugs.

Adults of the gregarious larval endoparasitoid Tachinaephagus zealandicus Ashmead (Hymenoptera: Encyrtidae) were collected from two species of carrion-inhabiting flies, Phormia regina Meigen (Diptera: Calliphoridae) and Hydrotaea aenescens Wiedemann (Muscidae), associated with the burnt remains of a domesticated pig, Sus scrofa L. (Artiodactyla: Suidae), during late summer in south central Pennsylvania. This represents the first reported occurrence of the wasp in the state and only the second in the mid-Atlantic region. Collection from P. regina is a new host record for T. zealandicus and also the first for this parasitoid being attracted to flies on burnt remains.