Ticks and tick-borne diseases are of increasing concern in the United States, and understanding tick behavior could be crucial to limiting the exposure of humans and other animals to ticks. Here, we wanted to understand...Ticks and tick-borne diseases are of increasing concern in the United States, and understanding tick behavior could be crucial to limiting the exposure of humans and other animals to ticks. Here, we wanted to understand the drivers of questing and burrowing in and . We used a factorial design to assess the effects of substrate (sand, soil, and rock), temperature (16° and 22° C), tick species ( and ), and competition (homogenous or heterogenous mixture of ticks in the arena) on tick behavior in laboratory arenas. Questing varied significantly between tick species, with 61% of questing compared to 35% of . Substrate similarly affected questing, with most ticks questing in the arenas with sand (83%) compared to arenas with rock (35%) or soil (25%). Burrowing behavior was also influenced by substrate; every tick in the arenas with rock (100%) and nearly all in the arenas with soil (98%) exhibited burrowing, whereas only 10% burrowed in sand. traveled longer distances than (23 ± 2.8 cm vs 9.7 ± 2.3 cm). The disparity in laboratory behavior between sand and rock/soil substrates might warrant further consideration in a field setting, as understanding factors that inhibit host-seeking behaviors of ticks can inform management of public spaces and potentially help mitigate tick-exposure.
Murine typhus, caused by , is re-emerging in many parts of the world. The disease is also called endemic typhus to differentiate from epidemic typhus (caused by ), and sometimes also named flea-borne typhus. Occasionally...Murine typhus, caused by , is re-emerging in many parts of the world. The disease is also called endemic typhus to differentiate from epidemic typhus (caused by ), and sometimes also named flea-borne typhus. Occasionally, literature sources will include as a causative agent of flea-borne typhus, but illnesses caused by are actually flea-borne spotted fever. Murine typhus occurs in warm, coastal areas worldwide. In the United States, most cases are reported from California, Texas, and Hawaii. Murine typhus is usually a self-limited febrile illness but about one-quarter of patients suffer organ complications. The disease is only infrequently fatal. Regarding disease ecology, the historical paradigm is that rats ( and ) are reservoirs of worldwide, with rat fleas () as primary vectors. More recently, researchers have proposed an alternative suburban murine typhus transmission cycle involving opossums, cat fleas, cats, and dogs in Texas, California, and rural Mexico. Because cat fleas feed on a variety of mammals, there may be other avenues for transmission, including stray or feral cats bringing cat fleas and other infected fleas into proximity with humans and possible aerosolization of infected flea feces. Additional fleas, ticks, lice, and mites may play a role in various areas throughout the world, but a striking lack of fundamental research on this topic makes drawing conclusions difficult. This review provides an overview of the history, epidemiology, diagnosis, and treatment of murine typhus, with special emphasis on its disease ecology.
The stridulation in the subfamily Triatominae has been identified as a means of communication between species, produced by the friction of the proboscis on the prosternal stridulatory groove. Despite its biological signi...The stridulation in the subfamily Triatominae has been identified as a means of communication between species, produced by the friction of the proboscis on the prosternal stridulatory groove. Despite its biological significance, this phenomenon remains understudied, with the signal's production seemingly contingent upon the morphology of the stridulatory groove. In this study, we examined the morphology of stridulatory grooves in females and males of five species and two subspecies of Mexican triatomines using morphometric and scanning electron microscopical analysis. Our findings reveal that all analyzed species exhibit triangular-shaped stridulatory grooves with parallel ridges covering the entire groove, bordered on each side, and covered with setae. Surprisingly, we observed noticeable differences in the number of ridges and inter-ridge distance between the species and ( 0.001 and 0.009, respectively), indicating sexual dimorphism in this aspect, a phenomenon not previously reported in the morphology of this structure. Our findings shed light on the intricate morphology of the stridulatory groove in Mexican triatomines, suggesting potential implications for their behavior and intra-specific communication.
Wingbeat frequency may serve as a distinctive physical signature for identifying mosquito species. However, variation in wingbeat frequency within species may compromise reliability of wingbeat frequency-based mosquito i...Wingbeat frequency may serve as a distinctive physical signature for identifying mosquito species. However, variation in wingbeat frequency within species may compromise reliability of wingbeat frequency-based mosquito identification. We examined the impact of mosquito density (number of females), time of day (day or night), gravid status, and age (days post-emergence) on the wingbeat frequency of three important vector mosquito species using infrared optical sensors. Wingbeat frequency of was significantly higher (6.2% and 9.5%) for single females compared to groups of five and ten females, respectively, and 9.4% higher during the daytime compared to nighttime. Wingbeat frequency was also significantly higher for gravid (9.4%) and (1.4%) than nongravid conspecifics. Within a short age range (five to seven days post-emergence), wingbeat in did not vary significantly. Our results highlight that both extrinsic (density and time of day) and intrinsic (gravid status) factors contribute to wingbeat variation, potentially posing challenges for development of wingbeat profile libraries and the classification of unknown specimens. Traps that aim to use wingbeat frequency and target specific cohorts of the population (i.e., host-seeking or gravid females) will need to account for differences in wingbeat frequency due to multiple factors.
Spatial and temporal differences in the relative abundance of arthropod vectors are important factors that influence the risk of disease for mammalian hosts. Seasonal changes in the diversity and abundance of fleas (Siph...Spatial and temporal differences in the relative abundance of arthropod vectors are important factors that influence the risk of disease for mammalian hosts. Seasonal changes in the diversity and abundance of fleas (Siphonaptera) in Richardson's ground squirrel () burrows were studied at two sites in central Saskatchewan. A total of 225 fleas (151 at an urban site and 74 at a rural site) were collected. Flea prevalence differed among seasons at the urban site but not at the rural site. Of the nine flea species detected (eight at the urban site and six at the rural site), , , , and are vectors of , the causative agent of plague. The presence and abundance of some fleas differed between sites and seasons. and were the most abundant species at the urban site during the spring and summer, respectively, while was the most abundant species at the rural site. Our findings may have implications for the management of the black-tailed prairie dogs () in southwestern Saskatchewan because they coexist with , are hosts for , and are at great risk of plague exposure/infection.
The Capivari-Monos Environmental Protection Area (EPA) is located in the southern part of the São Paulo city Green Belt. Since the 1950s, this region has been affected by uncontrolled urban sprawl, resulting in a change...The Capivari-Monos Environmental Protection Area (EPA) is located in the southern part of the São Paulo city Green Belt. Since the 1950s, this region has been affected by uncontrolled urban sprawl, resulting in a change in the ecological habits of some vector mosquitoes. Over the last two decades, cases of autochthonous bromeliad malaria associated with the presence of anopheline mosquitoes in the EPA have been recorded. the primary vector of plasmodia in the region, is abundant and found naturally infected with both and In light of this, the present study sought to update the catalog of mosquito fauna in this EPA, analyze mosquito diversity among sites with different degrees of conservation and compare species using different collection techniques. Field collections were carried out from March, 2015 to April, 2017. A total of 20,755 specimens were collected, distributed in 106 different taxa representing 16 genera. Analysis of the diversity among the sites based on the Shannon and Simpson indices showed that the most preserved of them had the lowest indices because of the dominance of . The results highlight the increase in the number of different taxa collected as different mosquito collection techniques were included, confirming the importance of using several strategies to ensure adequate sampling of a local mosquito fauna when exploring a greater number of ecotopes. Furthermore, the survey produced the most recent and complete list of mosquito species in the Capivari-Monos EPA, a refuge and shelter for native and introduced mosquito species where new biocenoses, including pathogens, vertebrate hosts, and vectors can form, allowing zoonotic outbreaks in the local human population to occur.
Flea-borne diseases are endemic in Texas, U.S.A., with an increasing incidence of flea-borne typhus and cat scratch disease. Knowledge of flea natural history could provide information to protect public health, yet many...Flea-borne diseases are endemic in Texas, U.S.A., with an increasing incidence of flea-borne typhus and cat scratch disease. Knowledge of flea natural history could provide information to protect public health, yet many knowledge gaps remain outside of plague-endemic regions. Our objective was to characterize seasonal activity patterns of fleas on common mammalian wildlife species and test fleas and wildlife for and pathogens. We performed one year of monthly trapping for rodents and medium-sized mammals in a national forest with high recreational use and urban encroachment in East Texas. From 90 mammal captures representing seven species, 101 fleas were collected representing spp., , and species. Virginia opossums () hosted 99% of the collected fleas (100 fleas) and a single flea was on an eastern woodrat (). Flea infestation prevalence of opossums was 79% (23/29). Mean flea abundance was 4.39 fleas, with intensity peaking in spring. One cat flea removed from an opossum was positive for . Furthermore, we identified tissue or blood of four raccoons () and one golden mouse () positive for . These findings provide an ecological basis for the maintenance of vectors and pathogens from sylvatic settings.
Land cover is recognized as an important determinant of mosquito community assemblages and pathogen transmission, but few studies have investigated the role of land cover in populations of La Crosse virus (LACV) vectors....Land cover is recognized as an important determinant of mosquito community assemblages and pathogen transmission, but few studies have investigated the role of land cover in populations of La Crosse virus (LACV) vectors. La Crosse virus is a zoonotic disease primarily maintained by native , with accessory transmission by invasive vectors and The objective of this study was to investigate the association between land cover composition and the egg abundances of LACV vectors in a city with endemic LACV transmission. Oviposition cups were deployed at sites ranging from recreational forests to urban areas. Mixed-effects regression models were used to test the relationships between land cover composition and species abundances. Sites characterized by large percentages of impervious and built surfaces were dominated by , but was the most abundant species in forested areas. was rare at all sites, but its presence was associated with higher percentages of forested land. These results indicate that forested areas may allow to maintain large populations near urban areas that are dominated by . Further research should explore the potential for these land cover-dependent population dynamics to influence LACV transmission cycles.
Mosquitoes (Diptera: Culicidae) and the pathogens they transmit represent a threat to human and animal health. Low-cost and effective surveillance methods are necessary to enable sustainable monitoring of mosquito distri...Mosquitoes (Diptera: Culicidae) and the pathogens they transmit represent a threat to human and animal health. Low-cost and effective surveillance methods are necessary to enable sustainable monitoring of mosquito distributions, diversity, and human interactions. This study examined the use of iNaturalist, an online, community-populated biodiversity recording database, for passive mosquito surveillance in the United Kingdom (UK) and Ireland, countries under threat from the introduction of invasive mosquitoes and emerging mosquito-borne diseases. The Mozzie Monitors UK & Ireland iNaturalist project was established to collate mosquito observations in these countries. Data were compared with existing long-term mosquito UK datasets to assess representativeness of seasonal and distribution trends in citizen scientist-recorded observations. The project collected 738 observations with the majority recorded 2020-2022. Records were primarily associated with urban areas, with the most common species and significantly more likely to be observed in urban areas than other species. Analysis of images uploaded to the iNaturalist project also provided insights into human-biting behavior. Our analyses indicate that iNaturalist provides species composition, seasonal occurrence, and distribution figures consistent with existing datasets and is therefore a useful surveillance tool for recording information on human interactions with mosquitoes and monitoring species of concern.
Brazil is endemic for both visceral (VL) and cutaneous (CL) clinical forms of leishmaniasis, poverty-associated diseases with worldwide distribution. parasites are the etiological agents of leishmaniases, which are tran...Brazil is endemic for both visceral (VL) and cutaneous (CL) clinical forms of leishmaniasis, poverty-associated diseases with worldwide distribution. parasites are the etiological agents of leishmaniases, which are transmitted to humans through the bites of infected phlebotomine sand flies. From 2018 to 2023, 15 cases of VL and 129 cases of CL were reported in Téofilo Otoni, an important economic center in the Brazilian state of Minas Gerais. Owing to the lack of data on the entomological fauna, the present study aimed to clarify this main aspect of leishmaniasis. From May, 2021 to April, 2023, entomological captures were performed monthly in ten neighborhoods in Teófilo Otoni. The influence of bioclimatic variables on insect populations was evaluated, and natural infection by spp. was investigated using molecular methods. A total of 306 specimens of 12 species of phlebotomine sand fly were collected. The majority (91.6%) were proven or putative vectors of leishmaniasis agents. The population of insects tended to increase during the cooler and drier months. Although infection was not detected in any of the samples, the presence of vectors provides conditions for the maintenance and expansion of the transmission cycle of leishmaniasis in Teófilo Otoni.
is the species of greatest concern for mosquito-borne disease in the Florida Keys. Previous locally transmitted dengue outbreaks in Key West (2009-2010) and Key Largo (2020) illustrate the need for an immediate and effec...is the species of greatest concern for mosquito-borne disease in the Florida Keys. Previous locally transmitted dengue outbreaks in Key West (2009-2010) and Key Largo (2020) illustrate the need for an immediate and effective response plan to maintain populations below threshold levels. An important part of the Florida Keys Mosquito Control District's vector response plan is adulticide application because it can provide an immediate reduction in adults in the community. It has become apparent that in the Florida Keys, and throughout Florida, resistance to the adulticide permethrin is prevalent. This study uses the CDC bottle bioassay method to look at resistance in collected from Key Largo, Vaca Key, and Key West, FL. Resistance was found in all three populations when exposed to permethrin and Sumithrin® but not malathion. Inhibitor testing revealed that esterase and glutathione transferase activity is involved in resistance to permethrin in Key Largo and Key West populations while oxidase activity is involved in resistance to permethrin in from Vaca Key. Lack of knockdown at the diagnostic time and previous studies detecting the presence of -associated allele mutations suggest knockdown resistance in all three populations. Results from this study show that there are multiple factors involved with resistance in the populations in the Florida Keys and that resistance mechanisms vary between islands. Continued surveillance will remain important so the most effective active ingredients can be used in response to future disease transmission.
In the United States, there has been a steady increase in diagnosed cases of tick-borne diseases in people, most notably Lyme disease. The pathogen that causes Lyme disease, is transmitted by the blacklegged tick (). Se...In the United States, there has been a steady increase in diagnosed cases of tick-borne diseases in people, most notably Lyme disease. The pathogen that causes Lyme disease, is transmitted by the blacklegged tick (). Several small mammals are considered key reservoirs of this pathogen and are frequently-used hosts by blacklegged ticks. However, limited studies have evaluated between-species host use by ticks. This study compared burdens and tick-associated pathogen presence in wild-caught (southern red-backed voles) and spp. (white-footed mice) in forested areas where the habitat of both species overlapped. Rodent trapping data collected over two summers showed a significant difference in the average tick burden between species. Adult spp. had an overall mean of 4.03 ticks per capture, while adult had a mean of 0.47 ticks per capture. There was a significant association between infection and host species with more spp. positive samples than (65.8% and 10.2%, respectively). This work confirms significant differences in tick-host use and pathogen presence between sympatric rodent species. It is critical to understand tick-host interactions and tick distributions to develop effective and efficient tick control methods.
Based on historical and recent records, an updated list of 244 nominal species and three undescribed mosquitoes from Mexico is presented. Since 1990, 15 species have been recorded for the first time in Mexico: , , , , ,...Based on historical and recent records, an updated list of 244 nominal species and three undescribed mosquitoes from Mexico is presented. Since 1990, 15 species have been recorded for the first time in Mexico: , , , , , , , , , , , , , , and . Five species were discovered and described: , , , and . Three species were discovered without yet describing or naming them: () sp. 1, () sp. 2, and sp. 3. Five species had been removed from the Mexican mosquito fauna: , , , , and . With the intention of updating the checklist of the mosquito species in Mexico, historical and recent species records were reviewed, as well as the review of entomological collections, resulting in the confirmation of the presence in Mexico of , , and . Morphological and molecular evidence confirms the presence of , while , , , , , and are removed from the Mexican mosquito fauna.
Amazonian savannas are among the most noteworthy landscape components of the coastal plain of French Guiana. Although they cover only 0.22% of the territory, they bring together a large part of the animal and plant diver...Amazonian savannas are among the most noteworthy landscape components of the coastal plain of French Guiana. Although they cover only 0.22% of the territory, they bring together a large part of the animal and plant diversity of this overseas region of France. This article outlines the results of the first study dedicated to mosquitoes (Diptera: Culicidae) of Amazonian savannas. Samplings were conducted in eight independent savannas evenly distributed along a transect of 170 km on the coastal plain of French Guiana. A total of 50 mosquito species were recorded, which is about 20% of the culicid fauna currently known in French Guiana. Among them, () and () are newly described based on both morphological features of the male genitalia and a DNA barcode obtained from type specimens. Diagnostic characters to assist their identification are provided and their placement within the infrasubgeneric classification of the subgenus is discussed.
Because the vertical distribution and diversity of blood-sucking flies are poorly known, we determined the diversity, structure, and composition of culicids between vertical vegetation strata. We evaluated the influence...Because the vertical distribution and diversity of blood-sucking flies are poorly known, we determined the diversity, structure, and composition of culicids between vertical vegetation strata. We evaluated the influence of microclimatic variables during different times of the day over a year. We used eight CDC traps baited with CO at a height of 1.5 m and 12-15 m. We conducted rank-abundance curves, similarity analysis (ANOSIM and SIMPER), and multivariate clustering with incidence and abundance data. We used GAM models to analyze the influence of strata (understory vs canopy), humidity, and temperature on insect richness and abundance. During the day, the difference between strata was mainly due to higher abundance of and ca in the understory. During the night, the differences were mainly due to higher abundance of , , and in the canopy, and in the understory. Seasonality played a role in the similarity between the strata. Diversity during the day was positively related to humidity and temperature, and nocturnal diversity increased with temperature but decreased with higher humidity. The effects of environmental factors on the spatiotemporal distribution of fly species are essential for epidemiological surveillance.