Culicoides biting midge species (Diptera: Ceratopogonidae) of the Obsoletus Group and the Pulicaris Complex are considered the major vectors of bluetongue and Schmallenberg viruses in Europe. Overwintering strategies of these arboviruses are controversially discussed, with the ongoing activity of vector species and a non-disrupted transmission cycle during winter being a plausible explanation. Although data on Culicoides winter activity are relatively scant, a seasonal vector-free period (SVFP), during which adult Culicoides are not or hardly active, is questionable. To determine winter activity and define SVFPs according to the EU Commission Regulation No 1266/2007, adult Culicoides were trapped weekly with UV-light traps from October to April 2019/2020 and 2020/2021 inside and outside stables on 16 farms throughout Germany. Temperature measurements were taken regularly at each trapping site since the temperature is a known driver of biting midge activity. In 960 indoor and outdoor catches, 32,377 Culicoides were trapped, with 90.9% of them belonging to the Obsoletus Group, 6.1% to the Pulicaris Complex and 3.0% to ‘other Culicoides’ according to morphological identification. The majority (61.3%) of Culicoides were trapped indoors, with substantial numbers of specimens collected from October to December, in March and in April, and only a few or no specimens in January and February. Obsoletus Group biting midges were active indoors for almost the entire winter. Outdoors, Culicoides numbers decreased from October to December, few or no specimens were caught from January to March, and high numbers were captured in April. Of the collected Culicoides, 2028 were blood-fed, of which 94.6% were trapped in the stables. The indoor SVFP, although calculated for blood-fed instead of parous females, lasted for almost 4 months (late November until mid-March) in winter 2019/2020 and 2 months (January and February) in winter 2020/2021. The outdoor SVFPs covered almost the entire study period in both winters, with slight differences between the onsets and the ends. The Culicoides activity significantly depended on temperature. Specimens of the Obsoletus Group were caught at an average temperature of 7.4°C (minimum 0.3°C) and of the Pulicaris Complex at an average temperature of 10.3°C (minimum 1.2°C). These temperatures were reached inside the stables over more extended periods than outside. The average indoor temperatures were 1.2 K higher than the average outdoor temperatures, although absolute temperature differences of up to 9.0 K were recorded. Based on Culicoides activity, the results of the present study indicate an almost continuous potential for virus transmission in winter within livestock houses.
{"title":"Winter activity of Culicoides (Diptera: Ceratopogonidae) inside and outside stables in Germany","authors":"Sarah Groschupp, Helge Kampen, Doreen Werner","doi":"10.1111/mve.12756","DOIUrl":"10.1111/mve.12756","url":null,"abstract":"<p><i>Culicoides</i> biting midge species (Diptera: Ceratopogonidae) of the Obsoletus Group and the Pulicaris Complex are considered the major vectors of bluetongue and Schmallenberg viruses in Europe. Overwintering strategies of these arboviruses are controversially discussed, with the ongoing activity of vector species and a non-disrupted transmission cycle during winter being a plausible explanation. Although data on <i>Culicoides</i> winter activity are relatively scant, a seasonal vector-free period (SVFP), during which adult <i>Culicoides</i> are not or hardly active, is questionable. To determine winter activity and define SVFPs according to the EU Commission Regulation No 1266/2007, adult <i>Culicoides</i> were trapped weekly with UV-light traps from October to April 2019/2020 and 2020/2021 inside and outside stables on 16 farms throughout Germany. Temperature measurements were taken regularly at each trapping site since the temperature is a known driver of biting midge activity. In 960 indoor and outdoor catches, 32,377 <i>Culicoides</i> were trapped, with 90.9% of them belonging to the Obsoletus Group, 6.1% to the Pulicaris Complex and 3.0% to ‘other <i>Culicoides</i>’ according to morphological identification. The majority (61.3%) of <i>Culicoides</i> were trapped indoors, with substantial numbers of specimens collected from October to December, in March and in April, and only a few or no specimens in January and February. Obsoletus Group biting midges were active indoors for almost the entire winter. Outdoors, <i>Culicoides</i> numbers decreased from October to December, few or no specimens were caught from January to March, and high numbers were captured in April. Of the collected <i>Culicoides</i>, 2028 were blood-fed, of which 94.6% were trapped in the stables. The indoor SVFP, although calculated for blood-fed instead of parous females, lasted for almost 4 months (late November until mid-March) in winter 2019/2020 and 2 months (January and February) in winter 2020/2021. The outdoor SVFPs covered almost the entire study period in both winters, with slight differences between the onsets and the ends. The <i>Culicoides</i> activity significantly depended on temperature. Specimens of the Obsoletus Group were caught at an average temperature of 7.4°C (minimum 0.3°C) and of the Pulicaris Complex at an average temperature of 10.3°C (minimum 1.2°C). These temperatures were reached inside the stables over more extended periods than outside. The average indoor temperatures were 1.2 K higher than the average outdoor temperatures, although absolute temperature differences of up to 9.0 K were recorded. Based on <i>Culicoides</i> activity, the results of the present study indicate an almost continuous potential for virus transmission in winter within livestock houses.</p>","PeriodicalId":18350,"journal":{"name":"Medical and Veterinary Entomology","volume":"38 4","pages":"552-565"},"PeriodicalIF":1.6,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/mve.12756","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142073227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Attila D. Sándor, Alexandra Corduneanu, Maria Orlova, Sándor Hornok, Alejandro Cabezas-Cruz, Angélique Foucault-Simonin, Joanna Kulisz, Zbigniew Zając, Mihai Borzan
Research into various bacterial pathogens that can be transmitted between different animals and may have zoonotic potential has led to the discovery of different strains of Bartonella sp. in bats and their associated ectoparasites. Despite their enormous species diversity, only a few studies have focussed on the detection of bacterial pathogens in insectivorous bats of boreal forests and their associated Macronyssidae and Spinturnicidae mites. We collected and molecularly analysed mite samples from forest-dwelling bat species distributed all along the boreal belt of the Palearctic, from Central Europe to Far East. Ectoparasitic mites were pooled for DNA extraction and DNA amplification polymerase chain reaction (PCRs) were conducted to detect the presence of various bacterial (Anaplasmataceae, Bartonella sp., Rickettsia sp., Mycoplasma sp.) and protozoal (Hepatozoon sp.) pathogens. Bartonella sp. DNA was detected in four different mite species (Macronyssidae: Steatonyssus periblepharus and Spinturnicidae: Spinturnix acuminata, Sp. myoti and Sp. mystacinus), with different prevalences of the targeted gene (gltA, 16-23S ribosomal RNA intergenic spacer and ftsZ). Larger pools (>5 samples pooled) were more likely to harbour Bartonella sp. DNA, than smaller ones. In addition, cave-dwelling bat hosts and host generalist mite species are more associated with Bartonella spp. presence. Spinturnicidae mites may transmit several distinct Bartonella strains, which cluster phylogenetically close to Bartonella species known to cause diseases in humans and livestock. Mites with ubiquitous presence may facilitate the long-term maintenance (and even local recurrence) of Bartonella-infestations inside local bat populations, thus acting as continuous reservoirs for Bartonella spp in bats.
{"title":"Diversity of bartonellae in mites (Acari: Mesostigmata: Macronyssidae and Spinturnicidae) of boreal forest bats: Association of host specificity of mites and habitat selection of hosts with vector potential","authors":"Attila D. Sándor, Alexandra Corduneanu, Maria Orlova, Sándor Hornok, Alejandro Cabezas-Cruz, Angélique Foucault-Simonin, Joanna Kulisz, Zbigniew Zając, Mihai Borzan","doi":"10.1111/mve.12757","DOIUrl":"10.1111/mve.12757","url":null,"abstract":"<p>Research into various bacterial pathogens that can be transmitted between different animals and may have zoonotic potential has led to the discovery of different strains of <i>Bartonella</i> sp. in bats and their associated ectoparasites. Despite their enormous species diversity, only a few studies have focussed on the detection of bacterial pathogens in insectivorous bats of boreal forests and their associated Macronyssidae and Spinturnicidae mites. We collected and molecularly analysed mite samples from forest-dwelling bat species distributed all along the boreal belt of the Palearctic, from Central Europe to Far East. Ectoparasitic mites were pooled for DNA extraction and DNA amplification polymerase chain reaction (PCRs) were conducted to detect the presence of various bacterial (Anaplasmataceae, <i>Bartonella</i> sp., <i>Rickettsia</i> sp., <i>Mycoplasma</i> sp.) and protozoal (<i>Hepatozoon</i> sp.) pathogens. <i>Bartonella</i> sp. DNA was detected in four different mite species (Macronyssidae: <i>Steatonyssus periblepharus</i> and Spinturnicidae: <i>Spinturnix acuminata</i>, Sp. <i>myoti</i> and Sp. <i>mystacinus</i>), with different prevalences of the targeted gene (<i>glt</i>A, 16-23S ribosomal RNA intergenic spacer and <i>fts</i>Z). Larger pools (>5 samples pooled) were more likely to harbour <i>Bartonella</i> sp. DNA, than smaller ones. In addition, cave-dwelling bat hosts and host generalist mite species are more associated with <i>Bartonella</i> spp. presence. Spinturnicidae mites may transmit several distinct <i>Bartonella</i> strains, which cluster phylogenetically close to <i>Bartonella</i> species known to cause diseases in humans and livestock. Mites with ubiquitous presence may facilitate the long-term maintenance (and even local recurrence) of <i>Bartonella</i>-infestations inside local bat populations, thus acting as continuous reservoirs for <i>Bartonella</i> spp in bats.</p>","PeriodicalId":18350,"journal":{"name":"Medical and Veterinary Entomology","volume":"38 4","pages":"518-529"},"PeriodicalIF":1.6,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/mve.12757","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142036289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chagas disease is considered one of the most important human parasitosis in the United States. This disease is mainly transmitted by insects of the subfamily Triatominae. The chemical vector control is the main tool for reducing the incidence of the disease. However, the presence of triatomines after pyrethroids spraying has been reported in some regions, as in the case of Triatoma infestans in Argentina and Bolivia. The presence of insects can be explained by the colonization from neighbouring areas, the reduction of insecticide dose to sublethal levels due to environmental factors, and/or by the evolution of insecticide resistance. In the last two scenarios, a proportion of the insects is not killed by insecticide and gives rise to residual populations. This article focuses on the toxicological processes associated with these scenarios in triatomines. Sublethal doses may have different effects on insect biology, that is, sublethal effects, which may contribute to the control. In addition, for insect disease vectors, sublethal doses could have negative effects on disease transmission. The study of sublethal effects in triatomines has focused primarily on the sequence of symptoms associated with nervous intoxication. However, the effects of sublethal doses on excretion, reproduction and morphology have also been studied. Rhodnius prolixus and T. infestans and pyrethroids insecticides were the triatomine species and insecticides, respectively, mainly studied. Insecticide resistance is an evolutionary phenomenon in which the insecticide acts as a selective force, concentrating on the insect population's pre-existing traits that confer resistance. This leads to a reduction in the susceptibility to the insecticide, which was previously effective in controlling this species. The evolution of resistance in triatomines received little attention before the 2000s, but after the detection of the first focus of resistance associated with chemical control failures in T. infestans from Argentina in 2002, the study of resistance increased remarkably. A significant number of works have studied the geographical distribution, the resistance mechanisms, the biological modifications associated with resistance, the environmental influences and the genetic of T. infestans resistant to pyrethroid insecticides. Currently, studies of insecticide resistance are gradually being extended to other areas and other species. The aim of this article was to review the knowledge on both phenomena (sublethal effects and insecticide resistance) in triatomines. For a better understanding of this article, some concepts and processes related to insect-insecticide interactions, individual and population toxicology and evolutionary biology are briefly reviewed. Finally, possible future lines of research in triatomine toxicology are discussed.
{"title":"What happens when the insecticide does not kill? A review of sublethal toxicology and insecticide resistance in triatomines.","authors":"Gastón Mougabure-Cueto, Georgina Fronza, Julieta Nattero","doi":"10.1111/mve.12753","DOIUrl":"https://doi.org/10.1111/mve.12753","url":null,"abstract":"<p><p>Chagas disease is considered one of the most important human parasitosis in the United States. This disease is mainly transmitted by insects of the subfamily Triatominae. The chemical vector control is the main tool for reducing the incidence of the disease. However, the presence of triatomines after pyrethroids spraying has been reported in some regions, as in the case of Triatoma infestans in Argentina and Bolivia. The presence of insects can be explained by the colonization from neighbouring areas, the reduction of insecticide dose to sublethal levels due to environmental factors, and/or by the evolution of insecticide resistance. In the last two scenarios, a proportion of the insects is not killed by insecticide and gives rise to residual populations. This article focuses on the toxicological processes associated with these scenarios in triatomines. Sublethal doses may have different effects on insect biology, that is, sublethal effects, which may contribute to the control. In addition, for insect disease vectors, sublethal doses could have negative effects on disease transmission. The study of sublethal effects in triatomines has focused primarily on the sequence of symptoms associated with nervous intoxication. However, the effects of sublethal doses on excretion, reproduction and morphology have also been studied. Rhodnius prolixus and T. infestans and pyrethroids insecticides were the triatomine species and insecticides, respectively, mainly studied. Insecticide resistance is an evolutionary phenomenon in which the insecticide acts as a selective force, concentrating on the insect population's pre-existing traits that confer resistance. This leads to a reduction in the susceptibility to the insecticide, which was previously effective in controlling this species. The evolution of resistance in triatomines received little attention before the 2000s, but after the detection of the first focus of resistance associated with chemical control failures in T. infestans from Argentina in 2002, the study of resistance increased remarkably. A significant number of works have studied the geographical distribution, the resistance mechanisms, the biological modifications associated with resistance, the environmental influences and the genetic of T. infestans resistant to pyrethroid insecticides. Currently, studies of insecticide resistance are gradually being extended to other areas and other species. The aim of this article was to review the knowledge on both phenomena (sublethal effects and insecticide resistance) in triatomines. For a better understanding of this article, some concepts and processes related to insect-insecticide interactions, individual and population toxicology and evolutionary biology are briefly reviewed. Finally, possible future lines of research in triatomine toxicology are discussed.</p>","PeriodicalId":18350,"journal":{"name":"Medical and Veterinary Entomology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142017932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Culicoides oxystoma Kieffer (Diptera: Ceratopogonidae) has been vectoring several arboviruses, protozoa and nematodes, leading to mortality and morbidity of livestock and wild ruminants in the tropics and subtropics. Insight into the bacterial communities associated with the vector species must be worked out. This work tries to inventorize the bacterial communities associated with this important vector species. Acquisition of gut microbiota may be the parental origin, while some are obtained through feeding during larval stages. Culicoides oxystoma possesses semi-aquatic life cycle strategies for egg-laying and larval survival. The bacteria associated with C. oxystoma were compared throughout (i) life stages: egg, larval instars, pupa, adult: male and female obtained from laboratory colony; (ii) field-collected adult: male and age-graded females; and (iii) natural breeding substrate and artificial rearing substrate. The culture-dependent bacteria were identified by Sanger sequencing of 16S rRNA, and haemolytic bacteria were screened on blood agar. Results show that Firmicutes and Proteobacteria are the predominant Phyla, of which Bacillus spp. was the most abundant across the life stages. Across the life history, Bacillus cereus, Bacillus pumilus, Bacillus tropicus, Lysinibacillus sp. and Paenibacillus sp. were retrieved routinely. Bacillus cereus and Alcaligenes faecalis were detected in the lab-reared specimens and shared between the natural breeding site and rearing medium. From the adults trapped across two locations, B. cereus, Bacillus flexus, A. faecalis, Enterococcus faecium and Pseudomonas sp. were isolated. The bacterial species associated with this vector may influence various physiological traits, such as vectorial capacity, digestion and larval development, which need further investigation.
{"title":"Isolation and comparative analysis of culturable bacterial communities associated with life stages, breeding and rearing substrates of Culicoides oxystoma Kieffer (Diptera: Ceratopogonidae) vector of bluetongue virus","authors":"Ankita Sarkar, Paramita Banerjee, Abhijit Mazumdar","doi":"10.1111/mve.12754","DOIUrl":"10.1111/mve.12754","url":null,"abstract":"<p><i>Culicoides oxystoma</i> Kieffer (Diptera: Ceratopogonidae) has been vectoring several arboviruses, protozoa and nematodes, leading to mortality and morbidity of livestock and wild ruminants in the tropics and subtropics. Insight into the bacterial communities associated with the vector species must be worked out. This work tries to inventorize the bacterial communities associated with this important vector species. Acquisition of gut microbiota may be the parental origin, while some are obtained through feeding during larval stages. <i>Culicoides oxystoma</i> possesses semi-aquatic life cycle strategies for egg-laying and larval survival. The bacteria associated with <i>C. oxystoma</i> were compared throughout (i) life stages: egg, larval instars, pupa, adult: male and female obtained from laboratory colony; (ii) field-collected adult: male and age-graded females; and (iii) natural breeding substrate and artificial rearing substrate. The culture-dependent bacteria were identified by Sanger sequencing of 16S rRNA, and haemolytic bacteria were screened on blood agar. Results show that Firmicutes and Proteobacteria are the predominant Phyla, of which <i>Bacillus</i> spp. was the most abundant across the life stages. Across the life history, <i>Bacillus cereus</i>, <i>Bacillus pumilus</i>, <i>Bacillus tropicus</i>, <i>Lysinibacillus</i> sp. and <i>Paenibacillus</i> sp. were retrieved routinely. <i>Bacillus cereus</i> and <i>Alcaligenes faecalis</i> were detected in the lab-reared specimens and shared between the natural breeding site and rearing medium. From the adults trapped across two locations, <i>B. cereus</i>, <i>Bacillus flexus</i>, <i>A. faecalis</i>, <i>Enterococcus faecium</i> and <i>Pseudomonas</i> sp. were isolated. The bacterial species associated with this vector may influence various physiological traits, such as vectorial capacity, digestion and larval development, which need further investigation.</p>","PeriodicalId":18350,"journal":{"name":"Medical and Veterinary Entomology","volume":"38 4","pages":"542-551"},"PeriodicalIF":1.6,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142017931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Most blow flies (Diptera: Calliphoridae) species are sarcosaprophagous during the larval stage, primarily feeding on the soft tissues of carcasses during the early stages of decomposition, making them valuable forensic indicators for minimum post-mortem interval (minPMI) estimations. Like other insects, their developmental rates are strongly influenced by the environmental temperature. Although several studies have examined the influence of temperature on the development of different blow fly species, the impact of cold temperatures remains largely unstudied, despite its potential forensic implications. The present study investigates the effect of three cold temperatures (0, -2.5 and -5°C) on the survival of Calliphora vicina embryos of five different ages (0%, 20%, 40%, 60% and 80% of the total embryonic development) and two exposure times (6 and 24 h). Our results revealed significant differences in egg survival at the earliest embryonic stages (0% and 20% of the total embryonic development), resulting in high mortality rates. While at 20% of the total embryonic development high mortality was only observed under -5°C, at 0% of the total embryonic development high mortality rates were observed at all the temperatures tested. Although C. vicina embryos demonstrate tolerance to cold temperatures once they have completed the first 20% of the total embryonic development, potentially mitigating the impact of cold weather events, the possibility of minPMI underestimations due to the death of the first egg batches should not be disregarded. Additionally, considering that the embryonic development stages may last for several days under low temperatures, caution should be taken in the analysis of entomological evidence if a cadaver is discovered following cold weather episodes.
{"title":"Survival of Calliphora vicina (Diptera: Calliphoridae) embryos under cold temperature conditions: forensic implications.","authors":"Jaime López-García, Daniel Martín-Vega","doi":"10.1111/mve.12749","DOIUrl":"https://doi.org/10.1111/mve.12749","url":null,"abstract":"<p><p>Most blow flies (Diptera: Calliphoridae) species are sarcosaprophagous during the larval stage, primarily feeding on the soft tissues of carcasses during the early stages of decomposition, making them valuable forensic indicators for minimum post-mortem interval (minPMI) estimations. Like other insects, their developmental rates are strongly influenced by the environmental temperature. Although several studies have examined the influence of temperature on the development of different blow fly species, the impact of cold temperatures remains largely unstudied, despite its potential forensic implications. The present study investigates the effect of three cold temperatures (0, -2.5 and -5°C) on the survival of Calliphora vicina embryos of five different ages (0%, 20%, 40%, 60% and 80% of the total embryonic development) and two exposure times (6 and 24 h). Our results revealed significant differences in egg survival at the earliest embryonic stages (0% and 20% of the total embryonic development), resulting in high mortality rates. While at 20% of the total embryonic development high mortality was only observed under -5°C, at 0% of the total embryonic development high mortality rates were observed at all the temperatures tested. Although C. vicina embryos demonstrate tolerance to cold temperatures once they have completed the first 20% of the total embryonic development, potentially mitigating the impact of cold weather events, the possibility of minPMI underestimations due to the death of the first egg batches should not be disregarded. Additionally, considering that the embryonic development stages may last for several days under low temperatures, caution should be taken in the analysis of entomological evidence if a cadaver is discovered following cold weather episodes.</p>","PeriodicalId":18350,"journal":{"name":"Medical and Veterinary Entomology","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142004540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Investigations of host feeding behaviour in haematophagous insects are critical to assess transmission routes of vector-borne diseases. Understanding if a certain species has ornithophilic or mammalophilic feeding behaviour can facilitate future studies focused on pathogens transmission to and from certain host species. Culicoides Latreille (Diptera: Ceratopogonidae) are vectors of several pathogens, which include arboviruses, bacteria and parasites to a considerable diversity of vertebrate hosts. However, most of the studies focused on feeding habits target Culicoides species that could transmit the Bluetongue virus, consequently with a mammalophilic feeding behaviour, leaving aside the Culicoides species that are involved in the transmission of vector-borne parasites to birds, such as Haemoproteus Kruse (Haemosporida: Haemoproteidae). This study aimed to investigate the source of blood meals of wild-caught Culicoides using molecular-based methods and to correlate our findings with the reports of Haemoproteus parasites in Culicoides species. Engorged Culicoides females were collected using ultraviolet (UV)-light traps at seven different localities in Lithuania in 2021–2023. Biting midges were dissected, and the abdomens of engorged females were used for molecular investigation of the blood meal source. A polymerase chain reaction (PCR) protocol that amplifies a fragment of the Cytochrome B gene of vertebrates was used. Obtained sequences were compared to available information in GenBank database to confirm the source of the blood meal. In total, 258 engorged Culicoides females, representing nine different species, were analysed. The source of blood meal was identified in 29.1% of them with most of the insects having fed on birds (74.7%) and the remaining on mammals (25.3%). Culicoides segnis Campbell, Pelham-Clinton was the only species to feed exclusively on birds; Culicoides from the Obsoletus group, C. pallidicornis Kieffer and C. punctatus Latreille were found to feed exclusively on mammals; C. festivipennis Kieffer, C. kibunensis Tokunaga and C. pictipennis Staeger had an opportunistic feeding behaviour, with the first two preferably feeding on birds. Due to their feeding behaviour and the presence of Haemoproteus parasites reported in the literature, C. festivipennis, C. kibunensis, C. pictipennis, and C. segnis play an important role in the transmission of those avian vector-borne parasite in the wild. These Culicoides species were already confirmed as being able to support the development of several Haemoproteus species and lineages. Future studies focused on understanding the epidemiology of avian pathogens transmitted by Culicoides should target these species.
调查食血昆虫的宿主取食行为对于评估病媒传播疾病的传播途径至关重要。了解某一物种是否具有嗜鸟类或嗜哺乳动物的取食行为,有助于今后重点研究病原体在某些宿主物种之间的传播途径。Culicoides Latreille(双翅目:Ceratopogonidae)是多种病原体(包括虫媒病毒、细菌和寄生虫)的传播媒介,可传播给多种脊椎动物宿主。然而,大多数研究都集中在以可能传播蓝舌病病毒的栉水母种为目标的取食习性上,因此,栉水母种具有嗜哺乳动物的取食行为,但却忽略了参与向鸟类传播病媒寄生虫的栉水母种,如克鲁兹血吸虫(血孢子虫科:Haemoproteidae)。本研究旨在利用分子方法调查野外捕获的Culicoides的血食来源,并将我们的发现与Culicoides物种中的血蛋白梭菌寄生虫的报告进行关联。2021-2023年,我们在立陶宛的七个不同地点使用紫外线诱捕器收集了被啮咬的雌性Culicoides。对咬蠓进行解剖,并利用吞食的雌蠓腹部对血食来源进行分子调查。采用聚合酶链式反应(PCR)方案扩增脊椎动物细胞色素 B 基因片段。将获得的序列与 GenBank 数据库中的现有信息进行比较,以确认血粉的来源。总共分析了 258 只被吞食的雌性库里科虫,它们代表了 9 个不同的物种。其中 29.1%的昆虫的血粉来源得到了确认,大部分昆虫以鸟类为食(74.7%),其余以哺乳动物为食(25.3%)。Culicoides segnis Campbell, Pelham-Clinton 是唯一一种只以鸟类为食的昆虫;Obsoletus 类中的 Culicoides、C. pallidicornis Kieffer 和 C. punctatus Latreille 被发现只以哺乳动物为食;C. festivipennis Kieffer、C. kibunensis Tokunaga 和 C. pictipennis Staeger 有机会性取食行为,前两种最好以鸟类为食。由于它们的取食行为和文献中报道的血包虫寄生虫的存在,C. festivipennis、C. kibunensis、C. pictipennis 和 C. segnis 在这些禽类病媒寄生虫的野外传播中扮演了重要角色。已证实这些恙虫属物种能够支持多个血吸虫物种和品系的发展。未来研究的重点应是了解由Culicoides传播的禽类病原体的流行病学。
{"title":"Culicoides biting midges feeding behaviour as a key for understanding avian Haemoproteus transmission in Lithuania","authors":"Margarita Kazak, Kristina Valavičiūtė-Pocienė, Simona Kondrotaitė, Mélanie Duc, Dovilė Bukauskaitė, Carolina Hernández-Lara, Rasa Bernotienė, Carolina Romeiro Fernandes Chagas","doi":"10.1111/mve.12752","DOIUrl":"10.1111/mve.12752","url":null,"abstract":"<p>Investigations of host feeding behaviour in haematophagous insects are critical to assess transmission routes of vector-borne diseases. Understanding if a certain species has ornithophilic or mammalophilic feeding behaviour can facilitate future studies focused on pathogens transmission to and from certain host species. <i>Culicoides</i> Latreille (Diptera: Ceratopogonidae) are vectors of several pathogens, which include arboviruses, bacteria and parasites to a considerable diversity of vertebrate hosts. However, most of the studies focused on feeding habits target <i>Culicoides</i> species that could transmit the Bluetongue virus, consequently with a mammalophilic feeding behaviour, leaving aside the <i>Culicoides</i> species that are involved in the transmission of vector-borne parasites to birds, such as <i>Haemoproteus</i> Kruse (Haemosporida: Haemoproteidae). This study aimed to investigate the source of blood meals of wild-caught <i>Culicoides</i> using molecular-based methods and to correlate our findings with the reports of <i>Haemoproteus</i> parasites in <i>Culicoides</i> species. Engorged <i>Culicoides</i> females were collected using ultraviolet (UV)-light traps at seven different localities in Lithuania in 2021–2023. Biting midges were dissected, and the abdomens of engorged females were used for molecular investigation of the blood meal source. A polymerase chain reaction (PCR) protocol that amplifies a fragment of the <i>Cytochrome B</i> gene of vertebrates was used. Obtained sequences were compared to available information in GenBank database to confirm the source of the blood meal. In total, 258 engorged <i>Culicoides</i> females, representing nine different species, were analysed. The source of blood meal was identified in 29.1% of them with most of the insects having fed on birds (74.7%) and the remaining on mammals (25.3%). <i>Culicoides segnis</i> Campbell, Pelham-Clinton was the only species to feed exclusively on birds; <i>Culicoides</i> from the Obsoletus group, <i>C. pallidicornis</i> Kieffer and <i>C. punctatus</i> Latreille were found to feed exclusively on mammals; <i>C. festivipennis</i> Kieffer, <i>C. kibunensis</i> Tokunaga and <i>C. pictipennis</i> Staeger had an opportunistic feeding behaviour, with the first two preferably feeding on birds. Due to their feeding behaviour and the presence of <i>Haemoproteus</i> parasites reported in the literature, <i>C. festivipennis</i>, <i>C. kibunensis</i>, <i>C. pictipennis,</i> and <i>C. segnis</i> play an important role in the transmission of those avian vector-borne parasite in the wild. These <i>Culicoides</i> species were already confirmed as being able to support the development of several <i>Haemoproteus</i> species and lineages. Future studies focused on understanding the epidemiology of avian pathogens transmitted by <i>Culicoides</i> should target these species.</p>","PeriodicalId":18350,"journal":{"name":"Medical and Veterinary Entomology","volume":"38 4","pages":"530-541"},"PeriodicalIF":1.6,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141988238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Melissa Florencio, Francisco Romulo Oilveira Magalhães, Aline Araujo Zuma, Cinara Lima Oliveira Lugathe, Dayana Rosa, Karina Riguete, Maria Cristina Machado Motta, Aparecida Alves do Nascimento, Jacenir Reis dos Santos Mallet, Georgia Correa Atella, Patrícia Fampa
Stomoxys calcitrans L. (Diptera: Muscidae), the stable fly, is a hematophagous insect of great veterinary importance, because it is a mechanical vector of diverse pathogens in livestock. The saliva of blood-feeding insects presents important pharmacologically active molecules that impair blood clotting, promote vasodilation and modulate the host immune system response, crucial processes for successful feeding. These properties also enable pathogens' transmission. In the present work, we describe an efficient protocol to dissect S. calcitrans salivary glands, their morphological characteristics and lipid profile. The mean length of the tubular gland is 3.23 mm with a bulbous posterior end and a narrow anterior end. Histological analysis revealed a monolayer of large polygonal epithelial cells with voluminous nuclei and high lipid content in their cytoplasm. Ultrastructural analysis showed that the epithelium is rich in mitochondria, free ribosomes, Golgi complex cisternae, presenting a great extension of rough endoplasmic reticulum that contains an electron-dense material. Lipid analysis by thin-layer chromatography showed that neutral fatty acids and phosphatidylcholine are predominant in the fly salivary glands. Lysophosphatidylcholine, an important signalling biomolecule involved in different metabolic processes, including host's immunomodulation and pathogens proliferation and differentiation, is also present.
{"title":"Morphological analysis and lipid composition of the stable fly Stomoxys calcitrans salivary glands reinforce important features of feeding behaviour\u0000 Análises morfológicas e composição lipídica das glândulas salivares de Stomoxys calcitrans, a mosca-dos-estábulos, reforçam importantes características de seu comportamento alimentar","authors":"Melissa Florencio, Francisco Romulo Oilveira Magalhães, Aline Araujo Zuma, Cinara Lima Oliveira Lugathe, Dayana Rosa, Karina Riguete, Maria Cristina Machado Motta, Aparecida Alves do Nascimento, Jacenir Reis dos Santos Mallet, Georgia Correa Atella, Patrícia Fampa","doi":"10.1111/mve.12751","DOIUrl":"10.1111/mve.12751","url":null,"abstract":"<p><i>Stomoxys calcitrans</i> L. (Diptera: Muscidae), the stable fly, is a hematophagous insect of great veterinary importance, because it is a mechanical vector of diverse pathogens in livestock. The saliva of blood-feeding insects presents important pharmacologically active molecules that impair blood clotting, promote vasodilation and modulate the host immune system response, crucial processes for successful feeding. These properties also enable pathogens' transmission. In the present work, we describe an efficient protocol to dissect <i>S. calcitrans</i> salivary glands, their morphological characteristics and lipid profile. The mean length of the tubular gland is 3.23 mm with a bulbous posterior end and a narrow anterior end. Histological analysis revealed a monolayer of large polygonal epithelial cells with voluminous nuclei and high lipid content in their cytoplasm. Ultrastructural analysis showed that the epithelium is rich in mitochondria, free ribosomes, Golgi complex cisternae, presenting a great extension of rough endoplasmic reticulum that contains an electron-dense material. Lipid analysis by thin-layer chromatography showed that neutral fatty acids and phosphatidylcholine are predominant in the fly salivary glands. Lysophosphatidylcholine, an important signalling biomolecule involved in different metabolic processes, including host's immunomodulation and pathogens proliferation and differentiation, is also present.</p>","PeriodicalId":18350,"journal":{"name":"Medical and Veterinary Entomology","volume":"38 4","pages":"508-517"},"PeriodicalIF":1.6,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141976068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}