Journal of medical entomology最新文献

Surveillance of triatomines or kissing bugs (Hemiptera: Reduviidae: Triatominae), the insect vectors of Trypanosoma cruzi, a Chagas disease agent, is hindered by the lack of an effective trap. To develop a kissing bug trap, we made iterative improvements over 3 years on a basic design resulting in 7 trap prototypes deployed across field sites in Texas, United States and Northern Mexico, yielding the capture of 325 triatomines of 4 species (Triatoma gerstaeckeri [Stål], T. sanguisuga [LeConte], T. neotomae [Neiva], and T. rubida [Uhler]). We began in 2019 with vertical transparent tarpaulin panel traps illuminated with artificial light powered by AC current, which were successful in autonomous trapping of flying triatomines, but were expensive, labor-intensive, and fragile. In 2020, we switched to white LED lights powered by a solar cell. We tested a scaled-down version of the vertical panel traps, a commercial cross-vane trap, and a multiple-funnel trap. The multiple-funnel traps captured 2.6× more kissing bugs per trap-day than cross-vane traps and approached the performance of the vertical panel traps in number of triatomines captured, number of triatomines per trap-day and triatomines per arthropod bycatch. Multiple-funnel traps required the least labor, were more durable, and had the highest triatomines per day per cost. Propylene glycol in the collection cups effectively preserved captured triatomines allowing for molecular detection of T. cruzi. The trapping experiments established dispersal patterns for the captured species. We conclude that multiple-funnel traps with solar-powered LED lights should be considered for adoption as surveillance and potentially mass-trapping management tools for triatomines.

The landing patterns of blood-sucking females (Diptera: Tabanidae) are largely influenced by their visual perceptions. When attacking humans, the shape of different body parts and overall brightness of the body could be the factors determining the place of blood-sucking. The visual attractiveness of the human body for tabanids was investigated through a black and a white mannequin in the Danube floodplain, Slovakia. The mannequins were covered by glue once a week. On both of the mannequins, 332 horse flies were stuck. The trapped horse flies on the mannequins belong to the genera Tabanus Linnaeus, 1758, Hybomitra Enderlein, 1922, Chrysops Meigen, 1803, Haematopota Linnaeus, 1758 and Atylotus (Linnaeus, 1767). Based on the trapped tabanids, the black mannequin is 6.06 times more attractive than the white one. The most tabanid carcasses were found on the lower limbs (56.32%) and the least occurred on the head (2.1%), the difference in their occurrence between the lower limbs and head of both mannequins was significant (P < 0.001). A similar significant difference was observed on certain parts of both mannequins on the taxonomical level of the genera Tabanus, Hybomitra, and Atylotus, the carcasses of which aggregated mostly on the lower limbs, rather than on the upper limbs and head.

The house fly (Musca domestica L.) is a ubiquitous fly species commonly associated with confined animal and urban waste storage facilities. It is known for its pestiferous nature and ability to mechanically vector numerous disease-causing pathogens. Effective control of adult house fly populations has traditionally relied upon insecticidal food baits; however, due to the overuse of insecticides, resistance has proven to yield many insecticidal baits and chemical classes less effective. Imidacloprid, the most widely used neonicotinoid, has been formulated and commonly used in house fly baits for over 2 decades. However, widespread evidence of physiological and behavioral resistance to imidacloprid has been documented. While previous studies have investigated the mechanisms of behavioral resistance to imidacloprid in the house fly, it remains unclear whether behavioral resistance is specific to imidacloprid or if behavioral cross-resistance exists to other compounds within the neonicotinoid class of insecticides. The current study used no-choice and choice-feeding bioassays to examine a lab-selected imidacloprid behaviorally resistant house fly colony for cross-resistance to other insecticides in the neonicotinoid chemical class. All flies exhibited high mortality (97-100%) in no-choice assays, even when exposed to imidacloprid, indicating physiological susceptibility to all tested neonicotinoids. House flies exhibited high mortality (98-100%) in choice assays when exposed to all neonicotinoid insecticides tested besides imidacloprid. These results confirm that imidacloprid behavioral resistance is specific to the compound imidacloprid and that alternative neonicotinoids remain viable options for control. Our study showed no evidence of behavioral cross-resistance to other compounds in the neonicotinoid class.

The number of tick-borne disease cases continues to rise in the United States, with Lyme disease the most frequently reported vector-borne disease nationally. Practical and effective tick control tools and strategies are needed to reduce tick encounters and tick-borne disease risk. Tick management tubes have shown varying efficacy when used as part of a tick management plan. To evaluate factors contributing to the efficacy of tick management tubes, this study assessed changes in tick tube deployment on tick burden on wild-caught Peromyscus mice, a primary reservoir for the bacterium causing Lyme disease, in Pennsylvania from 2021 to 2023. Over 2 years, tick tubes were deployed starting at different times of the year, with cotton removal from the tubes assessed every 2 weeks from April to November and tick burden on wild-caught mice assessed every 2 months from April to October of each year. The effect of distance between tick management tubes was assessed in year 3 of this study, with mouse tick burden assessed pre- and post-treatment with tick tubes at varying intervals in a field setting. There was a significant reduction in mouse tick burden between treated and control transects, and pre- and post-treatment transects. Tick tube distance did not affect cotton removal or tick burden on mice. Still, cotton removal was highest in September-October, and amount removed increased the longer tick tubes were deployed in the field, highlighting the long-term benefits of using tick tubes as part of an integrated tick management plan. Future investigations to evaluate the impact of tick management tubes on tick nymph density and infection would be valuable for assessing the effectiveness of tick management tubes in reducing tick bite risk.

Mosquitoes are a significant public health concern due to their role in transmitting various diseases. This study aimed to investigate mosquitoes' diversity, abundance, and ecological aspects, mainly focusing on Aedes (Diptera: Culicidae) mosquitoes, in central Nepal. The research explored variations across regions, seasons, altitudes, and years. Fieldwork for mosquito collection was conducted between May 2022 and October 2023. Dipping and pipetting methods were employed to collect larvae and pupae, whereas Biogents-Mosquitaire trap captured adult mosquitoes. A total of 7,223 (3,640 larvae and 3,583 adults) mosquitoes, belonging to 8 genera and 18 species, were collected and analyzed. Additionally, a survey examined 5,941 wet containers of 20 different types to assess potential breeding sites. The study revealed Culex pipiens (Linnaeus, 1758) (34.13%) and Aedes albopictus (Skuse, 1895) (27.36%) as the most abundant species. Interestingly, larvae were predominantly Aedes spp. (66.13%), whereas only 13.76% of adults belonged to this genus. Mosquito abundance varied across locations and altitudes, with Siwalik region (331-700 m asl) exhibiting the highest numbers. The monsoon season showed the highest overall abundance (1,492). Used tires were identified as significant breeding sites for Aedes mosquitoes, and infestation rates were higher in shaded containers. Seasonal analysis showed the House Index (HI) reaching its peak (10.92%) and the Breteau Index (BI) reaching 23.08% during the monsoon. Conversely, the Container Index (CI) reached its highest point (37.67%) in the post-monsoon season. The results emphasize the need for comprehensive disease prevention strategies at local and national levels, including public awareness campaigns, to address mosquito-borne illnesses in this famous tourist region.

Soft ticks (Argasidae) of the subgenus Pavlovskyella Pospelova-Shtrom are worldwide distributed parasites of medical importance. However, the systematics of the subgenus are currently under debate because genetic data shows that the group is paraphyletic. Meanwhile, species of Pavlovskyella continue to be discovered. In this study a novel species of the subgenus is described from specimens collected on a fox in central Chile. The larva of this new species differentiates from other Pavlovskyella spp. by having the following combination of characters: subpyriform dorsal plate; 15 pairs of setae, 7 anterolateral, 3 central, and 5 posterolateral, and hypostome with denticles in the distal third. Nymphs and adults of the species lack cheeks, eyes or bulging structures on the flank, but exhibit dorsoventral grooves, and humps on tarsi I, II, and III. Moreover, a patch of glabrous integument appears on the distal portion of coxal folds. A phylogenetic analysis using the mitogenome indicates a monophyletic group composed by Ornithodoros (Pavlovskyella) brasiliensis Aragão, Ornithodoros (Pavlovskyella) furcosus Neumann, Ornithodoros (Pavlovskyella) improvisus Muñoz-Leal & Venzal, and Ornithodoros (Pavlovskyella) rostratus Aragão. Interestingly, a phylogeny using 18S-28S rDNA sequences shows that South American Pavlovskyella spp. are paraphyletic, as depicted in previous studies. Adding species of the subgenus from the Neotropical region to phylogenetic analyses could aid to solve this paraphyly. Furthermore, this is the fifth species of Pavlovskyella described in South America, and the second in Chile.

Hemotropic mycoplasmas (hemoplasmas) are small pleomorphic bacteria that parasitize the surface of red blood cells of mammals. Hemoplasmas have been described in different species from the Camelidae Family, such as llamas and alpacas (South American camelids), but data on dromedary camels (Camelus dromedarius) are limited to a few reports. Somalia has one of the world's largest dromedary camel populations, and studies on hemoplasmas and tick-borne pathogens are lacking. Accordingly, this study aimed to screen dromedaries from Somalia for hemoplasmas by PCR-based assays. A total of 155 dromedary camel blood samples from 2 different areas of Mogadishu (n = 104) and the Lower Shabelle Region (n = 51) of the country were collected. All blood DNA samples were screened for hemoplasmas using a SYBR Green Universal Real-Time PCR (qPCR), nested PCR (nPCR), and conventional PCR (cPCR) assays targeting the 16S rRNA gene of hemoplasmas. Five out of 155 animals (3.23%; 95% confidence interval [CI]: 1.39-7.33%) were positive for hemoplasmas. A total of 346 (228 M, 117 F, and 1 nymph) ticks were collected from 79/155 (50.9%; 95% CI: 42.8-59.1%) dromedary camels with a mean of 4.4 ticks per animal. Ticks were identified as Rhipicephalus pulchellus (174/346; 50.3%), Hyalomma dromedarii (103/346; 29.8%), Hyalomma rufipes (35/346; 10.1%), Hyalomma marginatum (16/346; 4.6%), Rhipicephalus humeralis (14/346; 4.0%), Amblyomma lepidum (2/346; 0.6%), Amblyomma gemma (1/346; 0.3%), and Ornithodoros sp. (1/185; 0.5). This is the first study on the molecular screening for hemoplasmas in dromedary camels from Somalia and the first report of A. lepidum and R. humeralis in Somali dromedary camels.

Mosquitoes threaten over half of the world's population through vectored diseases such as malaria, zika, yellow fever, dengue, and chikungunya. Mosquitoes have a highly developed olfactory system attuned to chemotaxis relating to host-seeking, mating, and oviposition behavior. In this study, we aimed to determine the spatial efficacy of 2 plant-based repellent blends (Blend3 and Blend4 that had previously been found to successfully repel Aedes, Anopheles and Culex mosquitoes in wind tunnel assays) in excluding Aedes aegypti from the window entry. A new cage system was developed for parallel "no-choice" and "choice" olfactometric assays. In the no-choice trial, Blends 3 and 4, as well as commercial products (N, N-diethyl-3-methylbenzamide, p-menthane-3,8-diol [PMD], 3-(N-n-butyl-N-acetyl)-amino-propionic acid ethyl ester, and 2-(2-hydroxyethyl)-1-methylpropylstyrene 1-piperidine carboxylate), were adsorbed into filter papers of different sizes and placed in a window created between 2 attached bug dorms. Then, the number of mosquitoes entering the window was counted through a 6-min period. In choice olfactometric assays, Blends 3, 4, and PMD were adsorbed into filter paper and the number of mosquitoes moving away from Blend 3 and PMD were compared. No-choice assays showed that Blend3 (P < 0.001) and Blend4 (P = 0.0012) were more repellent than the best commercial product PMD. Additionally, while Blend 4 was significantly more repellent than Blend 3 (P = 0.012) in the choice assay, overall, these 2 blends show promise as new repellents for the spatial exclusion of Aedes aegypti from window entry alone or as part of a "push-pull'' strategy.

Numerous tick species are undergoing significant range expansion in Canada, including several Dermacentor spp Koch (Acari: Ixodidae). With the recent description of Dermacentor similis Lado in the western United States, additional research is required to determine the current range of this species. Five hundred ninety-eight Dermacentor spp. were collected from companion animals in the western Canadian provinces of British Columbia, Alberta, and Saskatchewan. Ticks were morphologically identified to species, followed by PCR and gel electrophoresis of the ITS-2 partial gene target (n = 595). Ninety-seven percent (n = 579/595) generated valid banding patterns. The banding pattern for the majority (74%, n = 206/278) of Dermacentor spp. from southern British Columbia was consistent with D. variabilis (Say), while 26% (n = 72/278) was consistent with D. andersoni Stiles. For samples from Alberta, 38% (n = 3/8) had banding patterns consistent with D. variabilis and 63% (n = 5/8) with D. andersoni. All (n = 293) ticks from Saskatchewan had banding patterns consistent with D. variabilis. After the description of D. similis was published, DNA sequencing of mitochondrial (16S rDNA gene, COI gene) and nuclear (ITS-2) markers was used to confirm the identity of 40 samples. Twenty-seven samples that had banding patterns consistent with D. variabilis from British Columbia were confirmed to be D. similis. One sample from Alberta and five from Saskatchewan were confirmed to be D. variabilis and seven samples from British Columbia were D. andersoni. The ITS-2 amplicons were not useful for differentiating between D. variabilis and D. similis. These results provide evidence of D. similis in western Canada and highlight that sequences of the mitochondrial genes are effective for distinguishing D. andersoni, D. variabilis, and D. similis.