Medical and Veterinary Entomology最新文献

Leishmaniasis comprises a group of vector-borne neglected tropical diseases caused by species of the obligatory intracellular parasite Leishmania, transmitted by the bite of dipteran sand flies. Infected dogs serve as the primary domestic reservoir of Leishmania parasites and are often found in close association with various arthropods, such as fleas and ticks. There have been recent reports of Leishmania infections occurring in areas non-endemic for sand fly species, leading to reconsideration of the hypothesis that other arthropods, such as ticks, may also play a significant role in the natural history and epidemiology of leishmaniasis. Here, we used a tick cell line as a tool to study Leishmania infantum and tick interaction. The results showed that L. infantum can bind to and proliferate inside Ixodes scapularis IDE8 tick cells. The infection did reduce tick cell viability and induce reactive oxygen species (ROS) production. Lipid profile analysis showed that the presence of L. infantum increased oxysterol in tick cells and influenced tick cell lipid biosynthesis, since an increase in glycerolipids and esterified cholesterol was observed in infected cells at 48 h. Further experiments are necessary to elucidate whether Leishmania can overcome the various biochemical and tissue barriers within ticks and be transmitted to the host.

This study reported hard tick (Ixodida: Ixodidae) infestation in sheep of Samara city, north of Baghdad, from June to December 2023. A total of 480 ticks were manually pulled out from the sheep with an ethanol-soaked tissue and preserved in plastic containers containing 70% ethyl alcohol. All samples were counted and examined individually under a light microscope to identify the genus. Preliminary microscopic examination revealed that the majority of the collected ticks were Hyalomma, with 91.4%, followed by Rhipicephalus (6.8%) and Ixodes (1.8%). Furthermore, Hyalomma was dominant across all months, with a peak relative abundance in October (100%). The peak relative abundances for Rhipicephalus (16%) and Ixodes (4.3%) occurred in July. Under further microscopic evaluation, morphological features demonstrated three species, namely, Hyalomma detritum (Koch), Hy. anatolicum (Koch) and Rhipicephalus sanguineus sensu lato (Latreille). To confirm genera and species, molecular diagnosis was performed, based on the COX1 gene, resulting in the identification of five species, namely, Hy. detritum, Hy. anatolicum, Hy. excavatum (Koch, 1844), Rh. sanguineus sensu lato and an unidentified Ixodes sp. While the Ixodes scapularis isolation unexpectedly revealed genetic resemblance to North American samples, indicating a wider geographical spread, the Hyalomma and Rhipicephalus isolates shared ancestry with other Middle Eastern strains, demonstrating regional genetic stability. These results showed the comprehensive diversity of tick species in sheep, including Hyalomma, Rhipicephalus and Ixodes, and also provided good epidemiological data to support the preventative procedures of tick-borne infections in Samarra city.

Surveillance and diagnostics are critical for the early detection, containment and eradication of exotic pests. For the screwworm fly, this is usually via targeted surveillance and exclusion testing of trap-caught flies, as well as the identification of larvae associated with myiasis wounds. We present a specific and sensitive real-time polymerase chain reaction (PCR) assay for the detection of the New World screwworm fly, Cochliomyia hominivorax Coquerel (Diptera: Calliphoridae). The assay targets the cytochrome oxidase subunit 1 (cox1) gene from adult flies or larvae and retains high analytical sensitivity when multiplexed with an existing assay for the Old World screwworm fly, Chrysomya bezziana Villeneuve (Diptera: Calliphoridae), achieving a limit of detection of less than 1 copy per microlitre of reaction. To assess its utility for surveillance and diagnostics, a novel non-destructive DNA extraction method was performed on spiked trap catches of field-caught flies, and on boiled and unboiled specimens of larval instars. The multiplexed assay detected 95% of spiked flies, and all screwworm flies from positive samples were retrieved and morphologically identified. Results from larval instars confirmed that the assay can be used for larvae, with higher sensitivity observed for unboiled larval instars. This molecular assay enables the simultaneous detection of Co. hominivorax and Ch. bezziana, offering a reliable alternative to existing single-target and destructive methods of bulk fly testing. It also holds potential for broader application in the identification of larval stages.

Rhipicephalus sanguineus Latreille (Ixodida: Ixodidae) has an economic impact as it is a blood-feeding ectoparasite transmitting numerous pathogens to humans and animals. The present study evaluated the acaricidal effect of eucalyptus essential oil (EO) with the concentrations (40%, 30%, 20%, 10%, 5% and 2.5%), eucalyptus nano-emulsion (ENE) with the concentrations (30%, 20%, 15%, 10%, 5%, and 2.5%), ENE combined with silver nanoparticles (ENE & SNPs) with the concentrations (5%, 4%, 3%, 2% and 1%) and SNPs with the concentrations (5%, 4%, 3%, 2% and 1%) on unfed adults of R. sanguineus sensu lato using the adult immersion test. There were two controls, one with tween 80 and the other without tween 80, while Bravecto® was used as an acaricidal reference. The nanoformulations were analysed by particle size, UV-visible spectroscopy, and transmission electron microscopy (TEM). The mortality of treated R. sanguineus was recorded daily for 7 days. The mortality of ENE and SNPs, EO and SNPs at 7 days was 96.6%, 90% and 80%, at concentrations of 5%, 40% and 5%, respectively. The lethal concentration to 50% mortality (LC₅₀) of EO, ENE, ENE and SNPs, and SNPs at 7 days was 6.65, 9.49, 2.23 and 4.08%, respectively. The particle size of nanoformulations was (83.08, 10.59 and 223.4 nm) for ENE, a mixture of SNPs, and ENE and SNPs, respectively. Scanning electron microscopy of treated adult R. sanguineus revealed numerous alterations in aeropyles of spiracular plates, anal grooves and mouthparts. The histopathological examination of the treated adult R. sanguineus showed degeneration in the cuticle, midgut and salivary gland. These findings demonstrate that eucalyptus oil could be used as part of an integrated pest management program for the control of R. sanguineus.

This study analysed the presence of Rickettsia (Rickettsiales: Rickettsiaceae) in fleas (Siphonaptera) associated with cricetid rodents in periurban localities of Gran La Plata, Argentina. Rodents were captured in three localities and fleas were collected directly from their fur. After DNA extraction, fleas were prepared for microscopic identification. PCR amplification of gltA and ompB genes was performed on each individual flea to detect and identify Rickettsia. The OmpB gene was sequenced and compared using nBLAST to initially identify its similarity with other sequences from GenBank. A phylogenetic tree was constructed to evaluate the relationships of the sequences obtained with others deposited in GenBank. Out of the 253 cricetids (seven species) captured, 87 fleas (four species) were collected. Of them, 10 fleas (11.5%) tested positive for Rickettsia. According to nBLAST and the phylogenetic tree results, sequences of this study were identified as R. felis Bouyer et al. Those sequences were obtained only from five of the seven cricetid species and from two of the three localities, as follows: from Street 143 and Diagonal 630, Arana neighbourhood, La Plata District: Polygenis (Polygenis) axius (Jordan and Rothschild) (n = 3) and Polygenis (Neopolygenis) atopus (Jordan and Rothschild) (n = 1); and from Balneario La Balandra, Berisso District: Polygenis (Polygenis) axius (n = 4), Polygenis (Neopolygenis) atopus (n = 1) and Craneopsylla minerva minerva (Rothschild) (n = 1). Our results confirm the presence of R. felis in fleas parasitizing cricetids in the periurban area of Gran La Plata, which could represent a risk to public health.

Blackflies (Diptera: Simuliidae) are notable for their painful bites and are significant vectors for various pathogens, posing risks to human and animal health. They are known vectors of several avian parasites such as Leucocytozoon Berestnev (Haemosporida: Leucocytozoidae), Trypanosoma Gruby (Trypanosomatida: Trypanosomatidae) and filarioid nematodes (Nematoda: Onchocercidae). However, the prevalence of infections and vector competence for different species remain poorly understood. In this study, we investigated wild-caught blackflies across various sites in Lithuania for their role as vectors of avian blood parasites, specifically Leucocytozoon, Trypanosoma, and filarioid nematodes, using microscopical analysis and molecular methods. A total of 229 female blackflies were collected, representing at least 10 species, with Simulium lineatum Meigen, S. equinum L. and S. maculatum Meigen being the most prevalent. Notably, S. cryophilum Rubtsov and S. rubzovianum Petrova were reported for the first time in Lithuania. Salivary glands or midgut of eight individuals were microscopically positive for parasites; Leucocytozoon sporozoites were the most common parasite stage (n=7), but trypanosomatid parasites were also detected (n=3). PCR analysis confirmed nine samples positive for at least one parasite, with Leucocytozoon detected in six samples, indicating the potential vector competence of S. cryophilum, S. rubzovianum, and S. aureum Fries. Trypanosoma avium Danilewsky and Trypanosoma theileri group Laveran, as well as monoxenous trypanosomatid Crithidia brevicula Frolov & Malysheva (Trypanosomatida: Trypanosomatidae), were detected. Splendidofilaria mavis Leiper (Nematoda: Onchocercidae) was also detected in blackflies. One specimen of S. cryophilum was positive for all three parasite genera, indicating the importance of this blackfly species in the transmission of avian parasites. This study adds new insights into the transmission dynamics of avian parasites among blackflies in Lithuania, highlighting the need for further research to explore ecological factors influencing vector competence and the epidemiology of avian blood parasites. These findings contribute to the understanding of blackfly-parasite relationships and underscore the necessity for targeted monitoring of avian blood parasites in changing ecological landscapes.

Insect infestation in grazing animals is an increasing problem due to factors such as global warming and increasing resistance to insecticides, which have a direct impact on animal health and welfare. According to reports from farmers, observations in zoopharmacognosy and the ingredients of commercial insecticides, various indigenous trees and shrubs with an insecticidal or repellent effect grow or can be planted on pastures. The aim of our systematic review (designed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement) was to identify perennial woody plants from Switzerland and the wider alpine region with a potential to affect the most common dipteran insects that are relevant for grazing animals. Based on a preselection of 399 plants, 114 publications including 403 laboratory and 10 outdoor experiments were found. Essential oils were evaluated most frequently (326 experiments), followed by extracts (118 experiments). Most frequently investigated were the aromatic herbs (Lamiales: Lamiaceae) Thymus vulgaris L., Rosmarinus officinalis Spenner, Lavandula angustifolia Miller, Salvia officinalis L., and the trees Punica granatum L. (Myrtales: Lythraceae), Laurus nobilis L. (Laurales: Lauraceae), Pinus pinea L. (Pinales: Pinaceae), Juniperus communis L. (Cupressales: Cupressaceae), Olea europaea L. (Lamiales: Oleaceae) and Alnus glutinosa (L.) Gaertner (Fagales: Betulaceae). These were studied for their effect (repellent, larvicidal, adulticidal) on mosquitoes (Diptera: Culicidae; Aedes spp., Anopheles spp., Culex spp.), and flies (Musca domestica L. (Diptera: Muscidae), and Lucilia sericata Meigen (Diptera: Calliphoridae)). The results concerning repellent or insecticidal effects provide valuable information about which trees and shrubs should be tested in future outdoor studies involving grazing animals.

Sucking lice (Anoplura) are highly specific parasites that depend extensively on their mammal hosts for survival. However, the climate to which their hosts are exposed can cause changes in their populations, independent of the protection provided by their hosts. Despite its harsh climate, arid northern Chile is home to a wide variety of rodents, particularly cricetids. This area comprises four distinct ecoregions with different sub-climates. We aimed to evaluate the spatial and seasonal variability of sucking lice (Anoplura) parasitizing rodents in northern Chile. Specifically, we analysed the association of environmental variables and host density with the louse point prevalence (P%), mean abundance (_MA) and mean infestation intensity (_MI). Rodent samples were collected during autumn and spring of 2011 and summer and winter of 2012 in 13 sites representative of the Coastal Desert (CD), Continental (Interior) Desert (ID), Andean Tropical (AT) and Pre-Andean Tropical (PAT) ecoregions. A total of 992 rodents of eight species were captured and anaesthetized, and lice were collected and identified. The P%, _MA and _MI of lice were estimated. The association of climatic variables (temperature, precipitation and relative humidity) and host density (capture success as a proxy) with louse P% and _MA was assessed using Spearman correlation and Fisher's test. Four lice species were identified based on external morphology (Hoplopleuridae: Hoplopleura aitkeni Johnson, Hoplopleura reducta Ferris, Hoplopleura sp. travassosi group; Poliplacidae: Polyplax spinulosa (Burmeister)). Hoplopleura aitkeni and H. reducta showed significant seasonal differences in P%, _MA and _MI in the AT and PAT ecoregions. In contrast, the H. sp. travassosi group showed no significant seasonal variation. Polyplax spinulosa was found exclusively on introduced rodents in the ID ecoregion, with distinct seasonal variations observed in Rattus norvegicus Berkenhout and Rattus rattus Linnaeus (Muridae). We reported 17 new host–parasite associations, and one lice species not previously described in the country. This study demonstrates that seasonal environmental variation does not equally impact all lice species, emphasizing the need for further research into the ecological and biological drivers of these dynamics.

Leishmaniases are zoonotic diseases with outbreaks influenced by environmental factors that can alter their epidemiological profiles. They are transmitted to humans and other vertebrates through the bite of a female phlebotomine infected with parasites of the Leishmania genus. The aim of this study was to conduct an entomological survey of the phlebotomine fauna to determine the distribution of potential vectors of leishmaniases, as well as to diagnose Leishmania spp. and evaluate food content. A sample study on potential leishmaniases vectors was conducted in an Environmental Protection Area (EPA) and Tinguá Federal Biological Reserve (TFBR), Nova Iguaçu municipality, in Rio de Janeiro State. Light traps were used to collect insects in the two study areas from September 2019 to March 2020. The data were obtained from six monitoring stations (MSs): MS₁, MS₂ and MS₃ (EPA), and MS₄, MS₅ and MS₆ (TFBR). Traps were installed in intradomicile, peridomicile, and residual forests in the EPA, while they were set up in wild animal burrows and rock formations in the TFBR. Phlebotomine samples (Diptera, Psychodidae) obtained from different MS'_s were used to estimate the standardized index of species abundance (SISA), diagnose specimens as Leishmania spp., and analyse the blood food content of the female sand flies. Seven primary or potential vectors were detected in relation to the total number of collected sand flies. These included Nyssomyia intermedia in the intradomicile, peridomicile, and residual forests of the EPA. This species was not detected in the TFBR, but other potential vectors were observed in both areas. During the diagnosis of Leishmania spp. in the sand flies, one specimen of Psychodopygus hirsutus hirsutus was positive for Leishmania (Viannia) braziliensis in the peridomicile (MS₃). A specimen of Psychodopygus davisi was observed feeding on Tamandua tetradactyla in MS₅ (TFBR), a potential reservoir of Leishmania. The presence of primary vectors, potential vectors, L. (V.) braziliensis, and a natural reservoir indicated the possible existence of a sylvatic and domestic transmission cycle in the American tegumentary leishmaniasis region.

Sarcoptes scabiei (Linnaeus) (Sarcoptiformes: Sarcoptidae), the cause of sarcoptic mange, has been documented as a pathogen affecting domestic and wild mammals, including coatis (Nasua spp. Storr (Carnivora: Procyonidae)). This parasitism impacts the health of infested animals and, in some cases, modifies the population dynamics of the affected species. The present study reports the first case of sarcoptic mange in a South American coati (Nasua nasua (Linnaeus)) from Peru. The Servicio Nacional Forestal y de Fauna Silvestre (SERFOR) rescued a coati from illegal trafficking in June 2024. The animal presented lesions compatible with sarcoptic mange, which was confirmed by morphologically diagnosing S. scabiei in the lesions. The mites were analysed molecularly, amplifying 1524 bp of the cytochrome c oxidase subunit I (cox1) gene using a PCR protocol. A 414 bp fragment of the cox1 sequence identified lineages identical to an Andean fox (Lycalopex culpaeus (Molina) (Carnivora: Canidae)) isolate of S. scabiei from Peru (OR362749). Future studies will be necessary to help understand the transmission of this mite between domestic and wild species.