Medical and Veterinary Entomology最新文献

Rodents represent the most diverse mammalian group and are considered important hosts for different groups of parasites serving as vectors for some zoonotic agents. Although there have been numerous studies conducted on occurrence records of ectoparasites on rodents, there is a paucity of knowledge regarding the biogeographical patterns of ectoparasites on this group of small mammals. In this study, a quantitative approach was employed to identify patterns of distributional congruence (PDCs) of ectoparasites of rodents in Iran. A total of 121 occurrence records for 37 species of ectoparasites (ticks, mites, lice and fleas) in Iran were analysed using endemicity analysis NDM/VNDM. Twelve consensus areas, characterised by 30 species, were found which were grouped into three PDCs. The PDCs showed that the highest endemicity values were primarily linked to the Zagros Mountains and central Persian areas. The patterns as a whole showed a clear tendency of the Zagros Mountains, forest steppe and central Persian desert basins ecoregions to provide possible areas of endemism. The current study extends the knowledge on the distribution patterns of four main groups of ectoparasites in association with rodent species in Iran and emphasises the significance of endemic zones in controlling management of reservoirs and vectors and conservation efforts.

Climate change is expected to expand the geographic ranges of ectoparasites, increasing the transmission of vector-borne diseases and necessitating a better understanding of ectoparasite–host trophic dynamics. Haematophagous ectoparasites can serve as valuable subsamples of their hosts, retaining isotopic values that reflect dietary information in both their blood meals and tissues. However, differences in the life histories and feeding strategies of lice, fleas and ticks may influence how host isotopic composition is preserved. Here, stable isotope values of carbon (δ¹³C) and nitrogen (δ¹⁵N) were used to investigate trophic interactions between ectoparasites and their mammalian hosts in three pairings: lice (Anoplura: Polyplacidae; n = 101) from Eurasian red squirrels Sciurus vulgaris L. (Rodentia: Sciuridae), fleas (Siphonaptera: Ceratophyllidae; n = 92) from fat dormice Glis glis L. (Rodentia: Gliridae) and ticks (Ixodida: Ixodidae; n = 16) from European hedgehogs Erinaceus europaeus L. (Eulipotyphla: Erinaceidae). Our findings indicate that ectoparasites reflect the dietary patterns of their hosts, with lice exhibiting the closest isotopic values, followed by fleas and ticks. All parasites had significantly higher δ¹⁵N values than their hosts, indicative of trophic enrichment, but their δ¹³C values varied. Notably, we found that the presence of a blood meal did not significantly affect the isotopic values found in lice and fleas, while ticks showed a significant difference between exoskeleton and blood meal in δ¹³C values. This study highlights the importance of understanding how the life histories of parasite species influence the preservation of isotopic host signals in order to be able to utilise stable isotope analyses of ectoparasites to infer host dietary niches and preferences, with broader implications for understanding host–parasite dynamics and disease transmission pathways.

Species belonging to the genus Lipoptena have received limited attention and have historically been subject to misidentifications. Recent records of L. fortisetosa in Europe have rekindled interest in these hippoboscids, leading to the discovery of a new species in Spain in 2024, which has been named L. andaluciensis. During an opportunistic sampling conducted in March 2023 and October 2024 on the Italian red deer (Cervus elaphus italicus), an Italian endemic subspecies, within the ancient relict lowland forest of the Bosco della Mesola Nature Reserve, hippoboscids morphologically identical to L. andaluciensis were collected and examined. This represents the first record of this species in Italy. In total, 257 specimens of Lipoptena were collected and analysed (161 in 2023 and 94 in 2024), all identified as L. andaluciensis. Additionally, Lipoptena specimens collected from fallow deer in 2007 within the same nature reserve, which had remained unidentified until now, were re-examined. A total of 66 specimens were reassessed, of which 63 were morphologically identified as L. andaluciensis and 3 as L. cervi. Morphological identification of the 2023 and 2024 specimens was further confirmed through molecular analysis using COI as a barcode marker. Molecular analysis also revealed the presence of a nuclear copy of the COI gene (NUMTs) in the nuclear genome of L. andaluciensis. The discovery of L. andaluciensis in Spain and in Italy since 2007 raises the possibility that this species has a much broader distribution, particularly at lower altitudes and within a Mediterranean climatic zone. It is plausible that its presence has so far gone unnoticed or has been misidentified.

Ticks are significant vectors of pathogens affecting both animals and humans, with the climate and environment of Sub-Saharan Africa providing ideal conditions for their growth. However, there are limited data on ticks and tick-borne pathogens (T&TBPs) in cattle in The Gambia. This study aimed to identify tick species on cattle and conduct molecular screening for T&TBPs. A total of 92 ticks were collected from 306 indigenous cattle. Ticks were first identified morphologically using taxonomic keys and then confirmed molecularly through DNA sequencing. DNA was extracted from the right fourth leg of six representative ticks for species confirmation, while 77 whole adult ticks were used for screening T&TBPs. Screening polymerase chain reaction (PCR) assays targeted Anaplasma marginale msp1β gene, Ehrlichia spp. dsb gene and hemotropic Mycoplasma spp. 16S rRNA gene. Ehrlichia-positive samples underwent additional assays targeting the sodB, 16S rRNA and groEL genes, followed by Sanger sequencing and phylogenetic analyses. A total of 92 (53 M, 37 F and two nymphs) ticks were collected from 30/306 (9.8%; 95% confidence interval [CI]: 5.6%–12.2%) cattle. Adult ticks were identified as Hyalomma marginatum (73/92; 79.3%; 45 M and 28 F), Amblyomma variegatum (8/92; 8.7%; 8 M), Hyalomma rufipes (4/92; 4.3%; 4 F) and Rhipicephalus evertsi (1/92; 1.1%; one F). The 16S rRNA sequences of six (four engorged female and two nymphs) ticks showed 98.6–100% identity with reference sequences from Rhipicephalus geigyi. Twelve out of 77 (15.6%) ticks tested positive for at least one TBP. Eight H. marginatum (six M and two F) (10.4%) were positive for Ehrlichia spp. dsb gene, three H. marginatum (two M and one F) (3.9%) for A. marginale and two (one H. marginatum F and one A. variegatum M) (2.6%) for hemotropic Mycoplasma spp. All Ehrlichia-positive samples showed 100% detection for the 16S rRNA gene and 62.5% for the sodB gene. BLASTn analysis revealed 99.3%–99.7% identity with Ehrlichia sp. from Brazil and 98.2%–99.3% identity with E. minasensis from Panama and Pakistan. Phylogenetic analysis grouped the sequences from this study with Ehrlichia spp. and E. minasensis from ticks in the Czech Republic and Brazil. This study identified various tick species and pathogens in cattle from The Gambia, including the first report of E. minasensis, A. marginale and hemotropic Mycoplasma spp. in the country. These findings highlight the importance of ongoing surveillance and research on tick-borne diseases in the region.

Bluetongue virus (BTV) is an arthropod-borne virus that is transmitted between ruminants by Culicoides (Order Diptera, Family Ceratopogonidae) midges. In September 2023, BTV serotype 3 (BTV-3/NET2023) emerged in the Netherlands, causing a devastating epidemic in sheep and cattle. The aim of this study was to determine which midge species contributed to the spread of BTV-3 and to what extent the virus is present in local midge populations. Midges were collected using Onderstepoort UV-light suction traps on BTV-affected farms in the centre of the Netherlands, from October 2023 till March 2024. Species, sex and parity of the midges were morphologically determined. Pooled female parous and gravid midges were subjected to pan-BTV and BTV-3 real-time polymerase chain reaction (PCR) testing. Pool prevalence, minimum infection rate (MIR) and infection rate (IR) were calculated. In total, 33,093 midges were morphologically identified, all being indigenous Culicoides species. Of these, 10,835 parous or gravid female midges were selected and pooled in 383 pools (mean 28.3 midges per pool, range 1–115). A total of 155 pools (40.5%) tested BTV positive, with a mean MIR/100 of 1.4 and an IR of 2.2 (95% confidence interval: 1.9–2.6). All positive pools were from batches that were collected in October 2023 (week 40 and 41). BTV-RNA was detected in the Culicoides species C. obsoletus Meigen, C. scoticus Downes and Kettle, C. chiopterus Meigen, C. dewulfi Goetghebuer and C. punctatus Meigen. The high proportion of BTV-PCR positive midge pools is indicative of a high vector competence for BTV-3/NET2023 of Dutch indigenous midges present on farms; it could potentially partly explain the rapid spread of the virus throughout the Netherlands.

The critical impact of mosquito-borne diseases on public health, along with the failure of current control strategies, highlights the need for novel mosquito control approaches mainly in tropical countries. This study explored the larvicidal properties of bacterial isolates from the egg surfaces of Aedes aegypti L. and Aedes albopictus Skuse (Diptera: Culicidae), the primary and secondary dengue vector mosquitoes in Sri Lanka. Among 30 bacterial isolates, a local strain of Pseudomonas mosselii Quesnel isolated from the egg surfaces of the dengue vectors demonstrated strong larvicidal activity against Ae. aegypti. Larvicidal assays using the bacterial supernatant (OD 1.7) and freeze-dried products were performed across concentrations ranging from 80 to 2.1 mg/mL. The LC₅₀ values for the supernatant were 55, 54 and 52 mg/mL at 24, 48 and 72 h, respectively, with corresponding LC₉₀ values of 91, 89 and 86 mg/mL. Freeze-dried supernatant showed LC₅₀ values of 2.73, 2.64 and 2.63 mg/mL, while freeze-dried bacterial culture showed higher toxicity with LC₅₀ values of 2.57, 2.51 and 2.44 mg/mL. Strong larvicidal activity was observed against Culex quinquefasciatus Say (Diptera: Culicidae), a primary vector of filariasis. The freeze-dried products retained their efficacy for up to 2 months. Ovicidal and adulticidal assays indicated no significant effects on mosquito eggs or adults. However, the active components of bacterial metabolites significantly impacted the development of Aedes larvae. Toxicity effects were observed in non-target organisms, including zooplankton and tadpoles. These findings suggest the local Ps. mosselii strain as a potential bio-larvicide against dengue vectors while underscoring the need for further environmental assessment.

Lizama-Schmeisser, N., Castro, E.S., Espinoza-Carniglia, M., Herrera, Y., Silva-de La Fuente, M.C., Lareschi, M. et al. (2024) Are Rattus rattus fleas invasive? Evaluation of flea communities in invasive and native rodents in Chile. Medical and Veterinary Entomology, 38(4), 599–613. Available from: https://doi.org/10.1111/mve.12739

The paper by Lizama-Schmeisser et al. (2024) appeared in a regular issue in error. It should be part of the Special Issue: Mammalian ectoparasite threats and management under a changing climate in the Global South.

We apologize for this error.

Records of infections by Leishmania spp. (Kinetoplastida: Trypanosomatidae) have been occurring in the last decade in Sergipe, Brazil. The capital, Aracaju, alone accounted for 44% of the total cases of the state for the visceral form between 2007 and 2016, with high numbers also in other municipalities that make up the metropolitan region. In this sense, this work aimed to carry out entomological surveillance actions in the municipalities of the Metropolitan Region of Aracaju and evaluate the characteristics of the peri-domestic environments that contribute to the maintenance of species richness and abundance. Entomological captures were carried out between 2021 and 2022 with Centers for Disease Control and Prevention (CDC)-type traps for three consecutive nights between twilight and dawn at the beginning of the dry and rainy periods in the peri-domestic area of residences in neighbourhoods peri-urban in the municipalities in the metropolitan region: Aracaju, Barra dos Coqueiros, Nossa Senhora do Socorro and São Cristóvão. The characteristics around the houses were also recorded in a field diary. Constancy, dominance for all species, the household infestation rate and the relative abundance index of the vector for epidemiologically interesting species were calculated. Chi-square tests and multivariate analyses of variance were also performed to search for associations between the vectors and aspects of the dwellings. In total, 752 phlebotomines were captured at 64 collection points. Seven species of phlebotomines were identified, including Lutzomyia longipalpis (Lutz & Neiva, 1912), Evandromyia lenti (Mangabeira, 1938) and Migonemyia migonei (França, 1920). The vector Lu. longipalpis was the species that showed the highest infestation in residences. The results also reveal a sex-specific association influenced by vegetation size, suggesting that denser vegetation may promote male aggregation, a behavioural trait that could be explored in the development of targeted vector control strategies. No significant association was recorded between abundance and environmental factors, which may be related to the difficulty of measuring this association in a heterogeneous environment with so many anthropic interferences in the urbanisation process. By evidencing the influence of ecological factors such as vegetation size on vector behaviour, this study offers insights to enhance leishmaniasis control strategies in Sergipe.

This study reports the first detection of Babesia aktasi and Anaplasma phagocytophilum in a bezoar goat (Capra aegagrus), providing insight into the presence of these pathogens in wild caprinae. The infected goat exhibited a localised ocular infection but showed no clinical signs of acute piroplasmid or Anaplasma infections. Microscopic examination of blood smears revealed low parasitemia of intra- and extraerythrocytic piroplasms and intragranulocytic morulae, consistent with chronic infection. PCR and sequence analysis confirmed that the Babesia species detected was B. aktasi, a recently described piroplasmid previously reported in domestic goats. Phylogenetic analysis placed the B. aktasi haplotype within the Babesia sensu stricto clade, closely related to sequences from domestic goats in Türkiye and an uncharacterised Babesia sp. from a red deer. The A. phagocytophilum strain detected in this study belonged to ecotype 1, which includes human pathogenic strains. These findings raise the possibility that bezoar goats may contribute to the natural maintenance of B. aktasi and A. phagocytophilum, highlighting their potential involvement in the enzootic cycles of these pathogens alongside domestic caprinae. Given that bezoar goats are the ancestors of modern domestic goats and that their habitats overlap in Anatolia, further research is needed to better understand the transmission dynamics, vector associations and zoonotic potential of these pathogens.

Culicoides biting midges (Diptera: Ceratopogonidae) are economically important biting flies known for transmitting pathogens like bluetongue virus to livestock. In order to control these insects and the diseases they are associated with, livestock producers employ a variety of preventive practices which commonly include insecticide use. The efficacy of insecticide treatments can wane over time as insects either develop resistance or the active ingredient is degraded in the environment. Sublethal insecticide exposures can change vector behaviour in ways that affect vectorial capacity. To determine whether Culicoides feeding behaviour is altered by sublethal exposure to commonly used agricultural insecticides, we exposed female C. sonorensis Wirth and Jones to permethrin and coumaphos at lethal concentrations (LC) ranging from LC₁₀ to LC₃₀. We also exposed midges to fluralaner at 100 mg/mL. Midges were offered a blood meal at 6, 12, 18 and 24 h post-exposure, and blood-feeding success was measured. We identified a significant inhibition of engorgement by permethrin up to 12 h post-exposure as well as by fluralaner up to 6 h post-exposure. Engorgement after coumaphos exposure was paradoxically higher in the LC₃₀ group after 18 and 24 h post-exposure, but decreased at the same timepoints for the LC₂₀ group. The different modes of action of each of these insecticides may account for their differing effects on Culicoides feeding.