Journal of Medical Entomology最新文献

Soft ticks (Argasidae) of the Pavlovskyella Pospelova-Shtrom subgenus are important vectors of relapsing fever spirochetes, which are agents of disease globally. South American representatives of the Pavlovskyella subgenus include 3 species: Ornithodoros (Pavlovskyella) brasiliensis Aragão, Ornithodoros (Pavlovskyella) furcosus Neumann, and Ornithodoros (Pavlovskyella) rostratus Aragão. Here, we describe a fourth species based on morphological and mitogenomic evidence of ticks collected in burrows of unknown hosts in central Chile. The larva of the new species separates from other South American soft ticks by the following combination of characters: 13 pairs of dorsolateral setae, dorsal plate hexagonal, hypostome blunt with denticles from apex almost to the base. Adults of this new species lack cheeks, possess a dorsoventral groove, and have humps, similar to O. (P.) brasiliensis; however, they lack bulging structures on the flanks of idiosoma. Moreover, females and males differ from O. (P.) rostratus by having 3 humps instead of spurs in tarsi I and from O. (P.) furcosus because of their smaller size and thinner anterior lip of the genital aperture in females. The phylogenetic analysis performed with mitogenomes of the Argasidae family depicts the new Pavlovskyella species from Chile in a monophyletic clade with other South American species in the subgenus, confirming a regional group.

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

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

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

With the increase in international travel and trade, in conjunction with the development of insecticide resistance, infestations of Cimex lectularius (L.) and Cimex hemipterus (F.) (Hemiptera: Cimicidae) have resurged globally in the last 2 decades. Recently, it was reported that C. hemipterus was also found in temperate regions, indicating the possibility of its expansion outside tropical regions. Cimex hemipterus has not been officially recorded in Korea since its initial description in 1934. Here, we report the first recent case of C. hemipterus in Korea based on morphological and molecular identification. Partial sequencing of the voltage-sensitive sodium channel gene revealed super-kdr mutations (M918I and L1014F) that are associated with pyrethroid resistance. This case report serves as a warning to intensify the bed bug surveillance system in Korea regarding the presence of C. hemipterus and to prepare effective alternative insecticides for pyrethroids.

In southern California, USA, annual reoccurrence of bluetongue infection in cattle (Bos taurus Linnaeus (Artiodactyla: Bovidae)) suggests that bluetongue virus (BTV) persists year-round but escapes detection during cooler months, reappearing when the weather gets warmer. The persistence of the virus in the adult biting midge vector, Culicoides sonorensis Wirth and Jones (Diptera: Ceratopogonidae), has been suggested. However, it is unknown whether adult C. sonorensis are sufficiently active during the winter months to transmit BTV throughout this period. This study captured host-seeking C. sonorensis in the Chino dairy region of southern California throughout the BTV interseasonal period (winter through early spring) over 3 years to assess adult host-seeking activity and adult survival during this period. BTV prevalence in host-seeking midges was also determined. Host-seeking nulliparous and parous C. sonorensis were consistently captured throughout the winter months, which combined with wintertime adult midge survival of ≤27 d, suggests the BTV overwintering is likely due to ongoing low-level transmission to available cattle hosts. However, BTV was not detected in midges captured during January through April in this study, suggesting that BTV transmission during the winter months may be occurring at too low a level to detect even with the substantial trapping effort applied in this study.

Gut bacterial communities in insects provide several beneficial roles like nutrition, digestion, fecundity, and survival of the host. The microbial communities of Culicoides spp. (Diptera: Ceratopogonidae) vary with parity, developmental stages, and environmental factors. Previous studies have revealed the presence of hemolytic bacteria in adult Culicoides peregrinus Kieffer (Diptera: Ceratopogonidae), an important vector of bluetongue virus (BTV). Our objectives were (i) to identify bacterial communities with hemolytic activities associated with all life stages and (ii) to compare between reared and field-collected adults including age graded females. Bacterial identification followed Sanger sequencing of 16S rRNA. In vitro biochemical characterizations including antibiotic sensitivity tests were also done. The majority of bacterial species were beta hemolytic with one, Alcaligenes faecalis, showing alpha hemolysis. Most bacterial species were observed in field-collected adults except Proteus spp. Throughout the life history of the vector, Bacillus cereus (CU6A, CU1E) and Paenibacillus sp. (CU9G) were detected indicating their possible role in blood digestion within the gut of this vector species. In vivo hemolytic activities of these culturable bacterial communities within this vector may be addressed in future. These hemolytic bacterial communities may be targeted to develop novel and effective strategies for vector control.

Three new species of DexosarcophagaTownsend, 1917 are described based on male specimens collected in Brazil, Dexosarcophaga sinoisp. nov., Dexosarcophaga autisferasp. nov., and Dexosarcophaga clavissp. nov. Male morphology is represented by photographs and detailed illustrations of terminalia. Dexosarcophaga carvalhoi (Lopes, 1980), Dexosarcophaga globulosaLopes, 1946, Dexosarcophaga limitata (Lopes, 1975), Dexosarcophaga paulistana (Lopes, 1982b), and Dexosarcophaga petraSantos, Pape and Mello-Patiu 2022 are recorded for the first time in Argentina. Also, Dexosarcophaga lenkoiLopes, 1968, Dexosarcophaga montana (Lopes, 1975), and Dexosarcophaga transitaTownsend, 1917 have their distribution expanded with new records. Dexosarcophaga transita is considered a senior synonym of Dexosarcophaga chaetosaBlanchard, 1939syn. nov., Dexosarcophaga itaquaDodge, 1966syn. nov., and Dexosarcophaga lopesiDodge, 1968syn. nov. With the addition of the new species and the new synonymies proposed, Dexosarcophaga now contains 58 species, of which 10 are recorded in Argentina and 35 in Brazil.

The production of mosquitoes for control programs or basic research is facilitated by the standardization of rearing conditions allowing the daily manipulation of thousands of individuals. It is crucial to develop mechanical or electronic systems for controlling the density of mosquitoes at each development stage with the aim of reducing costs, time, and human errors. We present herein an automatic mosquito counter using a recirculating water system allowing rapid and reliable counting of pupae without detectable increased mortality. Using Aedes albopictus pupae, we determined the density of pupae and the time of counting for which the device is most accurate, and evaluated the time saved using this device. Lastly, we discuss how this mosquito pupae counter can be useful in small-scale or mass-rearing contexts enabling a number of applications for research purposes as well as operational mosquito control programs.

Lone star ticks (Amblyomma americanum L.) are expanding within the northeast United States, a region historically focused on Ixodes scapularis-transmitted diseases. In Monmouth County, NJ, the shift has been dramatic, and lone star ticks now vastly outnumber blacklegged ticks. As a result, there is an enhanced need to focus on the potential health risks of A. americanum-transmitted pathogens, such as the emerging Heartland (HRTV) and Bourbon (BRBV) viruses. We screened 1,205 nymphal lone star ticks for HRTV and BRBV using RT-qPCR assays and detected BRBV in 3 ticks collected in Monmouth County, NJ, in 2021. Additionally, we sequenced a complete BRBV genome from a single infected specimen, finding 99.4% identity with human pathogenic isolates from the eastern-central United States. Our results have important public health implications for a region only recently becoming aware of public health risks posed by lone star ticks. Of note, we report successful detection of viral RNA in samples that were stored and intended for DNA preservation, for example, kept in ethanol at room temperature, which may reduce barriers for public health agencies seeking to expand their tick testing to include viruses.