The recent explosive outbreaks of Zika and chikungunya throughout the Americas has raised concerns about the threats that these and similar diseases may pose to the United States (U.S.). The commonly accepted association between tropical climates and the endemicity of these diseases has led to concerns about the possibility of their redistribution due to climate change and transmission arising from cases imported from endemic regions initiating outbreaks in the United States. While such possibilities are indeed well founded, the analysis of historical records not only confirms the potential critical role of traveling and globalization but also reveals that the climate in the United States currently is suitable for local transmission of these viruses. Thus, the main factors preventing these diseases from occurring in the United States today are more likely socioeconomic such as lifestyle, housing infrastructure, and good sanitation. As long as such conditions are maintained, it seems unlikely that local transmission will occur to any great degree, particularly in the northern states. Indeed, a contributing factor to explain the current endemicity of these diseases in less-developed American countries may be well explained by socioeconomic and some lifestyle characteristics in such countries.

Relevant evidence has shown that parasites process host-related information using chemical, visual, tactile, or auditory cues. However, the cues that are involved in the host–parasite interaction between Pediculus humanus capitis (De Geer 1767) and humans have not been identified yet. In this work, we studied the effect of human scalp components on the behavior of adult head lice. Filter paper segments were rubbed on volunteers' scalps and then placed in the experimental arena, where adult head lice were individually tested. The movement of the insects was recorded for each arena using the software EthoVision. Average movement parameters were calculated for the treatments in the bioassays such as total distance, velocity, number of times a head louse crossed between zones of the arena, and time in each zone of the arena. We found that scalp components induced head lice to decrease average locomotor activity and to remain arrested on the treated paper. The effect of the ageing of human scalp samples in the response of head lice was not statistically significant (i.e., human scalp samples of 4, 18, 40, and 60 h of ageing did not elicit a significant change in head louse behavior). When we analyzed the effect of the sex in the response of head lice to human scalp samples, males demonstrated significant differences. Our results showed for the first time the effect of host components conditioning head lice behavior. We discuss the role of these components in the dynamic of head lice infestation.

Culicoides sonorensis Wirth and Jones biting midges are the primary North American vectors of bluetongue virus (BTV), which infects domestic ruminant livestock and can cause high morbidity and mortality. Both virus and vector exhibit highly seasonal activity patterns, even in subtropical climates like southern California. However, the exact mechanism of BTV and Culicoides overwintering has been debated. In this study, we examined the supercooling point (SCP) and lower lethal temperature of a laboratory colony of C. sonorensis eggs, larvae, and pupae, as well as of field-collected larvae and pupae from subtropical (California) and temperate (Colorado) climates. Larvae and pupae succumbed to temperatures higher than their respective SCPs, indicating death from prefreezing cold injury. Eggs were the most cold-tolerant life stage, and were able to tolerate 1-h exposures to temperatures as low as –20 °C without suffering complete mortality. Larvae were the least cold-tolerant life stage and suffered complete mortality at < –4 °C, while temperatures of –9 to –10 °C were required to kill all pupae. Larvae and embryos suffered chronic cold injury after exposure to subzero temperatures, which increased mortality. Field-collected larvae succumbed to slightly higher temperatures ( > –3 °C) than colony larvae, but did not differ significantly in their survival. Culicoides sonorensis immatures did not cold harden when exposed to 4 °C for 24 h before freezing. Results of this study indicate that C. sonorensis eggs are more tolerant of environmental stress than previously thought. Further work is needed on C. sonorensis winter survival in the field to corroborate laboratory studies.

The relationship between engorgement weight of female Ixodes scapularis Say and characteristics of offspring was studied using field-collected females fed on rabbits in the laboratory. The number of eggs laid was positively related to maternal engorgement weight in one trial, and larval size (estimated by scutal area) was positively related to maternal engorgement weight in the other. These results suggest a trade-off in number of eggs produced versus average size of offspring, possibly determined during late engorgement. The adults for the two trials were collected from different sites in southern Rhode Island and in different seasons (the fall adults were newly emerged, while the spring adults had presumably lived through the winter), so it is not clear whether these results reflect genetic differences or subtle environmental differences between trials. Percent egg hatch and average fat content of larvae were not related to female engorgement weight. We present a modified method to measure lipid content of pooled larval ticks.

Creophilus maxillosus (L., 1758) is a common and widely distributed beetle species found on corpses, and its development duration is far longer than species belonging to the genus Calliphoridae and Sarcophagidae. Therefore, C. maxillosus can be used as a supplementary indicator to estimate minimum postmortem interval (PMI_min), and could greatly extend the range of PMI_min when the primary colonizers are no longer associated with the corpse or have emerged from pupae. Better descriptions of C. maxillosus development are needed to apply this species for forensic investigations. In this study, the development of C. maxillosus at seven constant temperatures ranging from 17.5–32.5 °C was studied. Through regression analyses, the simulation equations of larval body length variation with time after hatching were obtained. Isomegalen diagrams of the changes of larval body length over time at specific temperatures, and the isomorphen diagrams on the duration of different developmental milestones at specific temperatures were generated. In addition, thermal summation models of different developmental stages and the overall development process of C. maxillosus were generated through regression analysis, by estimating the development threshold temperatures (D₀) and the thermal summation constants (K). These results provide important tools for forensic investigations to generate a long-range of PMI_min estimation based on the development of C. maxillosus.

Chrysomya megacephala (Fabricius) is a forensically important fly that is found throughout the tropics and subtropics. We calculated the accumulated development time and transition points for each life stage from eclosion to adult emergence at five constant temperatures: 15, 20, 25, 30, and 35 ° C. For each transition, the 10th, 50th, and 90th percentiles were calculated with a logistic linear model. The mean transition times and % survivorship were determined directly from the raw laboratory data. Development times of C. megacephala were compared with that of two other closely related species, Chrysomya rufifacies (Macquart) and Phormia regina (Meigen). Ambient and larval mass temperatures were collected from field studies conducted from 2001–2004. Field study data indicated that adult fly activity was reduced at lower ambient temperatures, but once a larval mass was established, heat generation occurred. These development times and durations can be used for estimation of a postmortem interval (PMI).

A dynamical model of Anopheles gambiae larval and adult populations is constructed that matches temperature-dependent maturation times and mortality measured experimentally as well as larval instar and adult mosquito emergence data from field studies in the Kenya Highlands. Spectral classification of high-resolution satellite imagery is used to estimate household density. Indoor resting densities collected over a period of one year combined with predictions of the dynamical model give estimates of both aquatic habitat and total adult mosquito densities. Temperature and precipitation patterns are derived from monthly records. Precipitation patterns are compared with average and extreme habitat estimates to estimate available aquatic habitat in an annual cycle. These estimates are coupled with the original model to produce estimates of adult and larval populations dependent on changing aquatic carrying capacity for larvae and changing maturation and mortality dependent on temperature. This paper offers a general method for estimating the total area of aquatic habitat in a given region, based on larval counts, emergence rates, indoor resting density data, and number of households.

Altering the average daily temperature and the average daily rainfall simulates the effect of climate change on annual cycles of prevalence of An. gambiae adults. We show that small increases in average annual temperature have a large impact on adult mosquito density, whether measured at model equilibrium values for a single square meter of habitat or tracked over the course of a year of varying habitat availability and temperature.

Zoonotic cutaneous leishmaniasis (ZCL) is a prevalent vector-borne disease in the Golestan province of Iran, with Phlebotomus papatasi (Scopoli, 1786) serving as the main vector. The aim of this study was to model the probability of presence of this species in the study area, and to determine the underlying factors affecting its distribution. Three villages were selected from each county of the province and visited monthly for investigating ZCL. Sticky paper traps were used for collecting the sand flies to determine the species present. The presence of Ph. papatasi was modeled using genetic algorithm for rule-set production (GARP) and maximum entropy (MaxEnt) techniques. Both models showed the central and northern parts of the province with lowland areas were more vulnerable to Ph. papatasi propagation, in comparison with the southern parts with mountainous and forest areas. The area under curve (AUC) of MaxEnt model for the training points was calculated as 0.90, indicating excellent performance of the model in predicting Ph. papatasi distribution. Jackknife test showed that the factors with the greatest influence in vector distribution were slope, vegetation cover, annual mean temperature, and altitude. By using ecological niche models, it is possible to identify areas with higher probability of presence of Ph. papatasi, which guides public health policy makers for planning better vector control interventions.

The present study aimed to determine if the presence of immatures of the invasive blow fly species Chrysomya albiceps (Wiedemann) influences the adult behavior of the native species Lucilia eximia (Wiedemann) in Brazil. The level of attraction and oviposition by the native species was assessed in a dual-choice assay. The evaluation was based on sex and stage of ovarian development of L. eximia adults to a resource not colonized (NCR) or colonized (RPC) with eggs, different instars, or densities of C. albiceps. A significant difference in attraction was observed based on sex and stages of ovarian development. Males and nongravid females were more attracted to RPC, whereas gravid females preferred NCR. Moreover, males exhibited the lowest response in all assays among the three sex categories examined. In general, adults preferably oviposited on NCR rather than RPC. Also, between the eggs and second instar treatments, L. eximia laid more eggs on RPC with eggs than second instars (predatory stage). Lucilia eximia attraction to second-instar C. albiceps at different densities was marginally significant. Overall, results indicate the invasive species, C. albiceps, is impacting the behavior of the native blow fly, L. eximia, with regards to its attraction and colonization of vertebrate carrion, which could explain why native blow fly populations have significantly decreased since the introduction of C. albiceps.

Patterns of mosquito spatial persistence and temporal presence, as well as synchrony, i.e., the degree of concerted fluctuations in abundance, have been scarcely studied at finely grained spatial scales and over altitudinal gradients. Here, we present a spatial persistence, temporal presence, and synchrony analysis of four common mosquito species across the altitudinal gradient of Mt. Konpira in Nagasaki, Japan. We found that Aedes albopictus (Skuse) was more frequently found at the mountain base. In contrast, Aedes japonicus (Theobald) and Aedes flavopictus Yamada were common higher in the mountain, while Armigeres subalbatus (Coquillet) was uniformly present across the mountain, yet less frequently than the other species during the studied period. Our analysis showed that these spatial heterogeneities were associated with differences in landscape and microclimatic elements of Mt. Konpira. Temporally we found that presence across sampling locations was mainly synchronous across the four species and positively associated with rainfall and temperature. With the exception of Ae albopictus, where no significant synchrony was observed, mosquito species mainly showed flat synchrony profiles in Mt. Konpira when looking at the geographic (2-D) distance between their sampling locations. By contrast, when synchrony was studied across altitude, it was observed that Ae. flavopictus tracked the temperature synchrony pattern, decreasing its synchrony with the separation in altitude between sampling locations. Finally, our results suggest that differences in mosquito species persistence, temporal presence, and synchrony might be useful to understand the entomological risk of vector-borne disease transmission in urban landscapes.

We report on the use of the Gravid Aedes Trap (GAT) as a surveillance device for Aedes albopictus (Skuse) relative to the BG-Sentinel (BGS) trap in field studies conducted in Trenton, NJ, and on Hammond Island, Queensland, Australia. A parallel study conducted in Nha Trang, Vietnam, assessed the use of the GAT as an indoor surveillance device as well as the use of canola oil as a noninsecticide killing agent. In Trenton and Hammond Island, the GAT collected fewer male (0.40 ± 0.12 and 0.43 ± 0.30, respectively) and female (3.05 ± 0.67 and 2.7 ± 2.3, respectively) Ae. albopictus than the BGS trap (males: 3.54 ± 1.26 and 3.75 ± 0.83; females: 4.66 ± 1.18 and 3.9 ± 0.23) over their respective sampling periods (i.e., 24 h for the BGS and 1 wk for the GAT). Despite differences in capture rates, the percentage of traps positive for female Ae. albopictus was similar between the BGS and GAT (Trenton: 60.1 ± 6.3% and 64.4 ± 4.1%; Hammond: 87.5 ± 6.9% and 80.0 ± 8.2%). In Nha Trang, the GAT was equally effective indoors and outdoors with (10 g hay or 3 g fish food) and without (water or empty) infusion. Additionally, no significant decrease in collections was observed between GATs set with canola oil or long-lasting insecticidal net. In summary, both traps were successful in monitoring female Ae. albopictus over their respective trapping intervals, but would be best used to complement each other to monitor both sexes and all physiological stages of female Ae. albopictus. However, the versatility and low-cost of the GAT makes it an attractive alternative to the more expensive BGS trap.

The aim of the present study was to compare three different collecting methods, namely, baited traps, active capture with hand net, and Malaise traps, to establish which method is more appropriate for sampling different Calyptratae guilds inhabiting temperate forests of South America. Specifically, it was analyzed which technique or combination of techniques is more adequate for obtaining sarcosaprophagous Calyptratae, which are of great interest from a veterinary and medical viewpoint. Taxa were classified into guilds according to their biology. Active capture was the technique that registered the highest diversity of guilds. When analyzing sarcosaprophagous species, it was observed that their percentage of captures, diversity, and abundance showed clear differences in guild composition between the trapping techniques studied. From these analyses it can be concluded that baited traps and active trapping are complementary methods for capturing sarcosaprophagous Calyptratae species. From the perspective of the biodiversity of this group, the combination of both methodologies allows obtaining a more complete inventory of sarcosaprophagous species of austral temperate forests of South America.

Bed bugs, Cimex lectularius L., feed on humans, have increased exponentially in the past two decades in many major cities throughout the world, have caused intense infestations, and have become a significant health concern. Improved traps are needed to detect early infestations, to assess control programs, and for control of bed bugs. Carbon dioxide released alone or simultaneously with other attractants into three types of traps at the relatively low rate of 1 ml/min caught significantly more bed bugs than untreated controls in a 183- by 183-cm arena. This finding may enable CO₂ to be used more economically in traps. Three percent ammonium bicarbonate released at a rate of ≤0.03 ml/h also caught significantly more bed bugs than untreated controls. A blend of (E)-2-hexenal and (E)-2-octenal at concentrations of 0.025% or 0.1% each and released at 0.02 ml/h attracted significantly more bed bugs than untreated controls. These findings ought to improve detection of bed bugs.

The mosquito fauna of a coastal area of Santa Catarina state, Brazil (Baixada do Maciambu), was assessed, and possible mosquito larval habitats were mapped. Five new species records for the state are presented, two of which also are new genera records. From the 24 recognized species present in the area, 28% were from the subfamily Anophelinae and 72% from the Culicinae. The community structure throughout a year, the relevance of the new findings, and the medical importance of some species are discussed.

Cat fleas (Ctenocephalides felis (Bouché)) are a common flea species mostly found on cats and dogs. They not only cause discomfort to pets and their owners but also act as important vectors for human and pet zoonoses. Over the past 15 yr, the control of cat fleas on pets has been revolutionized through the use of various treatments. At present, fipronil and imidacloprid are used for flea control in Taiwan and are available in spot-on and spray formulations. Outside Taiwan, spinosad in tablet form is also available. In this study, we examined the effects of the aforementioned three insecticides on laboratory-reared and field-collected cat flea larvae. We developed a new technique for detecting flea susceptibility using a single larval bioassay with 96-well microtiter plates via contact and oral applications. Compared to the lab strain, the field strain exhibited lower susceptibility to fipronil, with the latter showing resistance levels two to four times higher than that of the former. By contrast, no difference in susceptibility was found between the two strains when tested with spinosad and imidacloprid. Our new technique was found to be stable, standardized, more efficient, convenient, and reproducible when compared to present techniques.

Mosquito-borne illnesses are of great concern throughout the world, and chemical insecticides are commonly employed to decrease mosquito populations. However, the developmental insecticide pipeline for vector control has primarily been filled by repurposed agricultural products, and is hampered by their widespread use and insecticide resistance. The present study was performed in the search for new chemical insecticides or insecticide synergists. Screening of 31 chalcone analogs was performed using Aedes aegypti (Linnaeus) first-instar larval toxicity assay, and oral feeding to Drosophila melanogaster's proper authority should be (Meigen). Synergism studies were performed by topically applying chalcones to adult female Ae. aegypti mosquitoes to examine its impact on activity of carbaryl, which was compared to piperonyl butoxide alone. Fourteen chalcone analogs had LC₅₀ values in the range of 0.4–38 ppm against first-instar Ae. aegypti larvae, and three chalcones displayed toxicity against D. melanogaster via feeding (LC₅₀ values ranged from 146–214 μg/ml). Two chalcones synergized carbaryl toxicity against adult Ae. aegypti with efficacy similar to piperonyl butoxide. As a result, it is concluded that chalcones may serve as novel insecticides and synergists after further structural optimization.

Puerto Rico detected the first confirmed case of chikungunya virus (CHIKV) in May 2014 and the virus rapidly spread throughout the island. The invasion of CHIKV allowed us to observe Aedes aegypti (L.) densities, infection rates, and impact of vector control in urban areas using CDC autocidal gravid ovitraps (AGO traps) for mosquito control over several years. Because local mosquitoes can only get the virus from infectious residents, detecting the presence of virus in mosquitoes functions as a proxy for the presence of virus in people. We monitored the incidence of CHIKV in gravid females of Ae. aegypti in four neighborhoods—two with three AGO traps per home in most homes and two nearby neighborhoods without AGO mosquito control traps. Monitoring of mosquito density took place weekly using sentinel AGO traps from June to December 2014. In all, 1,334 pools of female Ae. aegypti (23,329 individuals) were processed by real-time reverse transcription PCR to identify CHIKV and DENV RNA. Density of Ae. aegypti females was 10.5 times lower (91%) in the two areas with AGO control traps during the study. Ten times (90.9%) more CHIKV-positive pools were identified in the nonintervention areas (50/55 pools) than in intervention areas (5/55). We found a significant linear relationship between the number of positive pools and both density of Ae. aegypti and vector index (average number of expected infected mosquitoes per trap per week). Temporal and spatial patterns of positive CHIKV pools suggested limited virus circulation in areas with AGO traps.

Mosquitoes, which transmit infectious diseases, such as malaria and dengue fever, are harmful to human health. Thus, accurate and rapid identification of vectors is a critical step for the control of mosquito-borne diseases. However, phenotypic variations in adults, lack of recognizable features of the immature, and fragility of mosquitoes make identification difficult. Molecular approaches have been widely applied to identify mosquitoes, yet these methods have been focused only on the identification of a few species. This study used sequences of two mitochondrial genes, COI and ND2, and a ribosomal gene, ITS2, to design species-specific probes. Biochips thus developed were able to provide simultaneous identification of nine important medical and veterinary species, including the immature, from genera of Aedes, Anopheles, Armigeres, and Culex. This chip was also applied to samples collected from the field. Despite its inability to resolve the close affinity species of Culex quinquefasciatus and Culex pipiens molestus, pertinent biochips are expected to be applied to a mass screening method.

A field trial was conducted on residential properties in a Lyme disease endemic area of New Jersey to determine the efficacy of Maxforce Tick Management System (TMS) bait boxes modified with doxycycline hyclate-laden bait to reduce the acarological risk of Lyme disease and the utility of galvanized steel shrouds to protect the bait boxes from squirrel depredation and ability to routinely service these devices. The strategy began with a 9-wk deployment against larvae followed by a 17-wk deployment against nymphs and larvae the second year. Passive application of fipronil reduced nymphal and larval tick burdens on small mammals by 76 and 77%, respectively, and nymphal tick abundance by 81% on treated properties. In addition, the percentage of infected small mammals recovered from intervention areas following treatment was reduced by 96% for Borrelia burgdorferi and 93% for Anaplasma phagocytophilum. Infection prevalence in host-seeking nymphal ticks for both B. burgdorferi and A. phagocytophilum were reduced by 93 and 61%, respectively. Results indicate that Maxforce TMS bait boxes fitted with doxycycline-impregnated bait is an effective means of reducing ticks and infection prevalence for B. burgdorferi and A. phagocytophilum in both rodent reservoirs and questing Ixodes scapularis Say ticks. The protective shroud allows the device to be routinely serviced and protect against squirrel depredation.

Fipronil was evaluated as a systemic control agent for the rat flea Xenopsylla cheopis (Rothschild), the main vector of Yersinia pestis (Yersin), the causative agent of plague, in Madagascar. The effectiveness of fipronil as a systemic control agent against X. cheopis was assessed by determining the toxicity values of the “Lethal Dose 50″ (LD₅₀). Two techniques were used to evaluate the systemic action of the insecticide on the vector: 1) an artificial feeding device filled with blood–fipronil mixture from which X. cheopis was fed and 2) rodent hosts, Rattus norvegicus (Berkenhout) and Rattus rattus (L.), which fed on fipronil-treated bait. As a standardized control method, the susceptibility of X. cheopis to fipronil was evaluated by exposure to impregnated paper within World Health Organization (WHO) insecticide test protocol to compare its effect to the systemic activity of the studied insecticide. Results showed that when administered in a systemic way, fipronil appears to be more effective: the toxicity level was evaluated to be ninefold higher compared with the WHO test. Compared with other methods, which require indiscriminate dusting of rodent burrows and human dwellings, fipronil applied in a systemic way enables the direct targeting of the plague vector. Thus, this method appears to be a superior alternative to fipronil-dusting for the control of the main plague vector in Madagascar. However, subsequent tests in the field are necessary to confirm the suitability of fipronil administration in a systemic way on large scales.

Insect growth regulators (IGRs) such as lufenuron, methoprene, and pyriproxyfen have been important tools in the integrated pest management of cat fleas, Ctenocephalides felis (Bouché), for the past two decades. Other IGRs have been registered for the control of termite, dipteran, and lepidopterous pests including chlorfluazuron, cyromazine, dicyclanil, and precocene I, but have been not tested against C. felis. The intrinsic activity of IGRs was determined by exposing larvae to treated larval rearing media. The LC₅₀s of chlorfluazuron, cyromazine, dicyclanil, lufenuron, and precocene I against cat fleas were 0.19, 2.66, 0.04, 0.20, and 10.97 ppm, respectively. The LC₉₅s of chlorfluazuron, cyromazine, dicyclanil, lufenuron, and precocene I were 0.78, 51.24, 0.30, 0.62, and 175.05, respectively. The regression slopes of chlorfluazuron and lufenuron were 2.65 ± 0.24 and 3.40 ± 0.45 (SEM), respectively, and considerably steeper than the other IGRs tested (1.51 to 1.74). The intrinsic activity of IGRs tested is summarized as dicyclanil > chlorfluazuron = lufenuron > cyromazine > precocene I. The responses of the laboratory UCR strain to these IGRs can serve as a baseline of susceptibility until a more susceptible cat flea strain is found. Chlorfluazuron and dicyclanil look like promising candidates against cat fleas.

Several microorganisms have been shown to manipulate their host or vector to enhance their own transmission. Here we examined whether an infection with Borrelia afzelii affects its transmission between its bank vole (Myodes glareolus, Schreber, 1780) host and tick vector. Captive-bred bank voles were inoculated with B. afzelii or control medium, after which host preference of Ixodes ricinus L. nymphs was determined in a Y-tube olfactometer. Thereafter, infected and uninfected bank voles were placed in a semifield arena containing questing larvae to measure larval tick attachment. Engorged larvae were collected from these bank voles, molted into nymphs, weighed, and analyzed for infection by PCR.

Nymphs were attracted to the odors of a bank vole compared to ambient air and preferred the odors of an infected bank vole over that of an uninfected bank vole. In the semifield arena, infected male bank voles had greater larval tick burdens then uninfected males, while similar larval tick burdens were observed on females regardless of infection status. Nymphal ticks that acquired a B. afzelii infection had higher body weight than nymphs that did not acquire an infection regardless of the infection status of the vole. These results show that a B. afzelii infection in bank voles increases larval tick burden and that a B. afzelii infection in larvae increases nymphal body weight. This finding provides novel ecological insights into the enzootic cycle of B. afzelii.

Although female sand flies are best known as the vectors of Leishmania parasites and viruses, several previous reports have demonstrated that these insects can also act as vectors for the trypanosomes of bats, lizards, and snakes. In this report, we created an inventory of Phlebotomine sand flies from southern Thailand. A novel trypanosome was found in a specimen of Phlebotomus stantoni, and two sand fly species newly recorded in the country, Sergentomyia khawi and Sergentomyia hivernus, were described. PCR primer pairs specific for the internal transcribed spacer 1 (ITS1) and the small subunit ribosomal DNA (SSU rDNA) gene of trypanosomatids were used to demonstrate the presence of the parasite in the sand fly. In addition, the Cytochrome b (CytB) gene was used to identify the sand fly species. Among the 45 samples of the sand fly that were collected, seven samples were Ph. stantoni sand flies and a single sample was positive for Trypanosoma sp. through PCR analysis. This study represents the first detection of Trypanosoma sp. in a sand fly from Thailand. The ITS1 and SSU rDNA sequences indicated that this specimen is suspected to be a novel Trypanosoma species. Further studies of this suspected new Trypanosoma species, including its vertebrate hosts and pathogenic potential, are therefore necessary.

This study focuses on isolation of pathogenic bacteria from external and internal surfaces of cockroaches collected from houses and hospitals in Lahore. In total, 240 adult cockroaches were collected from houses and hospitals by hand or using sticky traps and food-bait traps. Cockroach species were identified, and microbial screening was done for external surfaces and gut tracts of cockroaches. Jaccard's index of similarity, Bray–Curtis' index of dissimilarity, and Shannon–Wiener's diversity index were used to measure the bacterial community diversity (all species of bacteria) in each habitat. Relative abundance and frequency were measured for each bacterial species on external and internal surfaces of cockroaches. Among human habitations, two major species of cockroaches were isolated, i.e., Periplaneta americana (P. americana) and Blattella germanica (B. germanica). Out of 240 cockroaches collected, 167 were P. americana and 73 were B. germanica. In total, 11 bacterial species were isolated, but no different bacterial load in each habitat was observed. The most common diagnostic bacterium isolated from the external surface of cockroaches was found to be Escherichia coli (10.31%). In contrast, the most common isolate from the internal gut tract of cockroaches was found to be Pseudomonas aeruginosa, with relative frequency of 19.96%. Jaccard's index of similarity of bacterial species found on cockroaches was highest (0.3125) in houses, whereas Bray–Curtis' index of dissimilarity was highest for hospitals (0.2174). The highest Shannon–Wiener's diversity index value was found in bacteria on cockroaches collected from the Punjab Institute of Cardiology (2.610632). No Salmonella typhi, Staphylococcus epidermidis, Enterobacter aerogenes, and Streptococcus pneumonia were found in the digestive tract of any cockroach.

In the Midwestern, Southwestern, and Southern part of the United States, the soft tick Ornithodoros turicata transmits the spirochete Borrelia turicatae, the causative agent of relapsing fever in humans. In this study, we report a simplified and an efficient method of in vitro feeding to evaluate O. turicata–B. turicatae interactions. Both nymphal and adult female ticks successfully acquired spirochetes upon in vitro feeding on the B. turicataeinfected blood. We also noted transstadial transmission of spirochetes to adult ticks that were molted from nymphs fed on B. turicatae-infected blood. A differential expression pattern for some of the B. turicatae genes was evident after acquisition and colonization of the vector. The levels of arthropod-associated lipoprotein Alp-mRNA were significantly upregulated and the mRNA levels of factor H binding protein FhbA and immunogenic protein BipA were significantly downregulated in the spirochetes after acquisition into ticks in comparison with spirochetes grown in culture medium. In addition, genes such as bta124 and bta116 were significantly upregulated in spirochetes in unfed ticks in comparison with the levels noted in spirochetes after acquisition. These findings represent an efficient in vitro blood-feeding method to study B. turicatae gene expression after acquisition and colonization in these ticks. In summary, we report that B. turicatae survive and develop in the tick host when acquired by in vitro feeding. We also report that B. turicatae genes are differentially expressed in ticks in comparison with the in vitro-grown cultures, indicating influence of tick environment on spirochete gene expression.

Phlebotomines (Diptera: Psychodidae) are vectors of several etiological agents of human and animal diseases, including protozoans of the gender Leishmania. Precarious socioeconomic conditions and uncontrolled population growth directly influence the transmission risk of parasites and the urbanization of vector species, previously restricted to wild environments. The Marajó Archipelago is considered a high incidence area of leishmaniasis in the Brazilian Amazon. However, it is poorly studied. The aim of this study was to assess the adaptation processes of phlebotomine species to anthropized environments in this region. For this purpose, the phlebotomine fauna was compared between three municipalities of the Marajó Archipelago: Anajás, Portel, and São Sebastião da Boa Vista. To survey the phlebotomine fauna, CDC (Center for Disease Control) light traps were installed in the wild areas and in the intra and peridomiciliary areas of rural and urban environments. The environments studied presented a diversified phlebotomine fauna, with higher richness in the wild environment (15 species), followed by the rural (seven species), and finally, the urban environment (three species). A migration of wild fauna to the adjacent anthropized areas (rural environment) and to urban areas was observed, evidencing the adaptation process of this vector to anthropized environments in the studied region. Thus, our study evidenced that the disorganized human occupation and utilization of the landscape might cause the invasion of urban areas by wild populations of phlebotomines, in this way enabling the settlement of urban leishmaniasis transmission cycles.

Rift Valley fever (RVF) is a mosquito-borne viral zoonosis that is found in most regions of sub-Saharan Africa, and it affects humans, livestock, and some wild ungulates. Outbreaks are precipitated by an abundance of mosquito vectors associated with heavy persistent rainfall with flooding. We determined the impact of flood-irrigation farming and the effect of environmental parameters on the ecology and densities of primary and secondary vectors of the RVF virus (RVFV) in an RVF-epidemic hotspot in the Tana River Basin, Kenya. Mosquito sampling was conducted in farms and villages (settlements) in an irrigated and a neighboring nonirrigated site (Murukani). Overall, a significantly higher number of mosquitoes were collected in farms in the irrigation scheme compared with villages in the same area (P < 0.001), or farms (P < 0.001), and villages (P = 0.03) in Murukani. In particular, key primary vectors of RVFV, Aedes mcintoshi Marks and Aedes ochraceous Theobald, were more prevalent in the farms compared with villages in the irrigation scheme (P = 0.001) both during the dry and the wet seasons. Similarly, there was a greater abundance of secondary vectors, particularly Culex univittatus Theobald and Culex pipiens (L.) in the irrigation scheme than in the Murukani area. Rainfall and humidity were positively correlated with mosquito densities, particularly the primary vectors. Adult floodwater mosquitoes and Mansonia spp. were collected indoors; immatures of Ae. mcintoshi and secondary vectors were collected in the irrigation drainage canals, whereas those of Ae. ochraceous and Aedes sudanensis Theobald were missing from these water bodies. In conclusion, irrigation in RVF endemic areas provides conducive resting and breeding conditions for vectors of RVFV and other endemic arboviruses.

Putative sensory structures in the food canal, and distal vestibule region entering the canal of Tabanus atratus F., are described. Two pairs of sensilla were observed in the walls of the vestibule—a distal pair of the basiconic type, and a pair of setifiorm sensilla at the base of the vestibule. Vestibular sensilla were constant in type, number, and position. Conversely, setiform sensilla in right and left walls of the food canal varied in number from one fly specimen to another, and lacked evidence of pairing (i.e., sensilla in one wall did not necessarily have a counterpart in the other wall). Food canal sensilla were of setiform design, with the exception of a single basiconic sensilla in each lateral wall of the food canal in every fly. When the food canal was partitioned into four equidistant regions, setiform sensilla were aggregated in the two distal-most regions, with relatively few sensilla observed in the two proximal canal regions. This aggregation was significant, leading to rejection of the null hypothesis that setiform sensilla were evenly distribution throughout the length of the food canal. Basiconic sensilla were always located in the distal-most region of the food canal.

Amblyomma maculatum Koch (Acari: Ixodidae), the primary vector for Rickettsia parkeri, may also be infected with a rickettsia of unknown pathogenicity, “Candidatus Rickettsia andeanae.” Infection rates with these rickettsiae vary geographically, and coinfected ticks have been reported. In this study, infection rates of R. parkeri and “Ca. R. andeanae” were evaluated, and rickettsial DNA levels quantified, in 335 questing adult A. maculatum collected in 2013 (n = 95), 2014 (n = 139), and 2015 (n = 101) from Oktibbeha County, MS. Overall infection rates of R. parkeri and “Ca. R. andeanae” were 28.7% and 9.3%, respectively, with three additional A. maculatum (0.9%) coinfected. While R. parkeri-infected ticks were detected all three years (34.7% in 2013; 13.7% in 2014; 43.6% in 2015), “Ca. R. andeanae” was not detected in 2013, and was detected at rates of 10.8% in 2014, and 15.8% in 2015. Interestingly, rickettsial DNA levels in singly-infected ticks were significantly lower in “Ca. R. andeanae”-infected ticks compared to R. parkeri-infected ticks (P < 0.0001). Thus, both infection rates and rickettsial DNA levels were higher for R. parkeri than “Ca. R. andeanae.” Infection rates of R. parkeri were also higher, and “Ca. R. andeanae” lower, here compared to A. maculatum reported previously in Kansas and Oklahoma. As we continue to monitor infection rates and levels, we anticipate that understanding temporal changes will improve our awareness of human risk for spotted fever rickettsioses. Further, these data may lead to additional studies to evaluate potential interactions among sympatric Rickettsia species in A. maculatum at the population level.

Amblyomma maculatum Koch (the Gulf Coast tick) is an aggressive, human-biting ixodid tick distributed throughout much of the southeastern United States and is the primary vector for Rickettsia parkeri, an emerging human pathogen. Amblyomma maculatum has diverse host preferences that include white-tailed deer, a known reservoir for Ehrlichia and Anaplasma species, including the human pathogens E. ewingii and E. chaffeensis. To examine more closely the potential role of A. maculatum in the maintenance of various pathogenic Ehrlichia and Anaplasma species, we screened DNA samples from 493 questing adult A. maculatum collected from six U.S. states using broad-range Anaplasmataceae and Ehrlichia genus-specific PCR assays. Of the samples tested, four (0.8%) were positive for DNA of Ehrlichia ewingii, one (0.2%) was positive for Anaplasma platys, and one (0.2%) was positive for a previously unreported Ehrlichia species closely related to Ehrlichia muris and an uncultivated Ehrlichia species from Haemaphysalis longicornis ticks in Japan. No ticks contained DNA of Ehrlichia chaffeensis, Ehrlichia canis, the Panola Mountain Ehrlichia, or Anaplasma phagocytophilum. This is the first identification of E. ewingii, A. platys, and the novel Ehrlichia in questing Gulf Coast ticks; nonetheless the low prevalence of these agents suggests that A. maculatum is not likely an important vector of these zoonotic pathogens.

Culex (Melanoconion) pedroiSirivanakarn & Belkin 1980 and Culex (Melanoconion) ribeirensisForattini & Sallum 1985 are two morphologically very similar species of the Pedroi subgroup of mosquitoes in the Spissipes section of the subgenus Melanoconion of the genus Culex L. 1758. We carried out an analysis of the mitochondrial cytochrome c oxidase I (COI) DNA variation between these two species. The recent observation of sympatric coexistence in a forested area of Rio de Janeiro State (Brazil) triggered the need to validate these two species previously identified based on morphology. We concluded that the COI is a useful tool for identification of Cx. pedroi and Cx. ribeirensis.

Aedes aegypti (L.) is one of the most important arboviral vectors worldwide. Vector control is targeted at immature and adult stages; however, eggs are resistant to desiccation and may repopulate treated areas long after treatment ceases. We investigated the effect of age on Ae. aegypti egg hatching rates using newly colonized populations (F2) from an arid region. We found a strongly negative association where older eggs had lower hatch rates. The capacity of eggs to survive for long periods of time has implications on mosquito control. In addition, the accumulation of eggs in containers should be accounted for in abundance modeling efforts where populations may grow rapidly early in the season.

Francisella tularensis and Rickettsia spp. have been cultured from Haemaphysalis leporispalustris Packard, but their prevalence in this tick has not been determined using modern molecular methods. We collected H. leporispalustris by flagging vegetation and leaf litter and from lagomorphs (Lepus californicus Gray and Sylvilagus bachmani (Waterhouse)) in northern California. Francisella tularensis DNA was not detected in any of 1,030 ticks tested by polymerase chain reaction (PCR), whereas 0.4% of larvae tested in pools, 0 of 117 individual nymphs, and 2.3% of 164 adult ticks were PCR-positive for Rickettsia spp. Positive sites were Laurel Canyon Trail in Tilden Regional Park in Alameda Contra Costa County, with a Rickettsia spp. prevalence of 0.6% in 2009, and Hopland Research and Extension Center in Mendocino County, with a prevalence of 4.2% in 1988. DNA sequencing revealed R. felis, the agent of cat-flea typhus, in two larval pools from shaded California bay and live oak leaf litter in Contra Costa County and one adult tick from a L. californicus in chaparral in Mendocino County. The R. felis in unfed, questing larvae demonstrates that H. leporispalustris can transmit this rickettsia transovarially. Although R. felis is increasingly found in diverse arthropods and geographical regions, prior literature suggests a typical epidemiological cycle involving mesocarnivores and the cat flea, Ctenocephalides felis. To our knowledge, this is the first report of R. felis in H. leporispalustris. Natural infection and transovarial transmission of this pathogen in the tick indicate the existence of a previously undocumented wild-lands transmission cycle that may intersect mesocarnivore-reservoired cycles and collectively affect human health risk.

Being able to efficiently differentiate between male and female individuals in the immature forms of insects allows for investigations into sexually dimorphic patterns of growth rates and gene expression. For species lacking sex-specific morphological characteristics during these periods, alternative methods must be devised. Commonly, isolation of sex determination genes reveals sex-specific band patterns and allows for markers that can be used in insect control. For blow flies, a family that includes flies of medical and forensic importance, sex has previously been identified in some members using the male-specific exon in the transformer gene. This gene is relatively conserved between members of the genera Cochliomyia and Lucilia (Diptera: Calliphoridae), and we isolated a portion of this gene in an additional forensically and medically important blow fly genus using the widespread Chrysomya megacephala (F.). We found a relatively high level of conservation between exons 1 and 2 of transformer and were able to amplify a region containing the male-specific exon in C. megacephala. A sex-specific molecular diagnostic test based on the presence of sexually dimorphic PCR product bands showed the expected genotype for adults and intrapuparial period specimens of known sex. The same result could be obtained from single third-instar larval specimens, opening up the possibility to not only determine if development rates are sex dependent, but also to investigate the development of sexually dimorphic traits of interest in C. megacephala.

The markedly anthropophilic and endophilic behaviors of Aedes aegypti (L.) make it a very efficient vector of dengue, chikungunya, and Zika viruses. Although a large body of research has investigated the immature habitats and conditions for adult emergence, relatively few studies have focused on the indoor resting behavior and distribution of vectors within houses. We investigated the resting behavior of Ae. aegypti indoors in 979 houses of the city of Acapulco, Mexico, by performing exhaustive indoor mosquito collections to describe the rooms and height at which mosquitoes were found resting. In total, 1,403 adult and 747 female Ae. aegypti were collected, primarily indoors (98% adults and 99% females). Primary resting locations included bedrooms (44%), living rooms (25%), and bathrooms (20%), followed by kitchens (9%). Aedes aegypti significantly rested below 1.5 m of height (82% adults, 83% females, and 87% bloodfed females); the odds of finding adult Ae. aegypti mosquitoes below 1.5 m was 17 times higher than above 1.5 m. Our findings provide relevant information for the design of insecticide-based interventions selectively targeting the adult resting population, such as indoor residual spraying.