Advances in the release mechanisms of bluetongue virus / 生物工程学报

Bluetongue virus (BTV) causes Bluetongue (BT) of ruminants vectored by culicoides midges. It is also a classic model for studying the release mechanism of non-enveloped virus. This review begins with the infection and assembly of BTV, then summarizes the advances of different ways of releasing BTV. This includes BTV-induced autophagy and the release as extracellular vesicles via multivesicular bodies, BTV-induced apoptosis and the lytic release, as well as different pathways of release through budding via plasma membrane. The regulatory mechanisms of NS3 which is a key non-structural protein during the release of BTV are also discussed, providing a basis for further understanding the molecular mechanisms underpinning the infection, proliferation and release of BTV.

Diversity of biting midges Culicoides (Diptera: Ceratopogonidae), potential vectors of disease, in different environments in an Amazonian rural settlement, Brazil

Abstract INTRODUCTION: The Culicoides transmit a variety of pathogens. Our aim was to survey the Culicoides species occurring in an Amazonian rural settlement, comparing abundance, richness, and diversity in different environments. METHODS: Culicoides were captured using CDC light traps. The Shannon-Wiener (H') and Rényi indices were used to compare species diversity and evenness between environments, the equitability (J') index was used to calculate the uniformity of distribution among species, and similarity was estimated using the Jaccard similarity index. A permutational multivariate analysis of variance was applied to assess the influence of environment on species composition. A non-metric dimensional scale was used to represent the diversity profiles of each environment in a multidimensional space. RESULTS: 6.078 Culicoides were captured, representing 84 species (45 valid species/39 morphotypes). H' values showed the following gradient: forest > capoeira > peridomicile > forest edge. The equitability J' was greater in capoeira and forests compared to peridomiciles and the forest edge. The population compositions of each environment differed statistically, but rarefaction estimates indicate that environments of the same type possessed similar levels of richness. Species of medical and veterinary importance were found primarily in peridomiciles: C. paraensis, vector of Oropouche virus; C. insignis and C. pusillus, vectors of Bluetongue virus; C. filariferus, C. flavivenula, C. foxi, and C. ignacioi, found carrying Leishmania DNA. CONCLUSIONS: This study indicates that diversity was higher in natural environments than in anthropized environments, while abundance and richness were highest in the most anthropized environment. These findings suggest that strictly wild Culicoides can adapt to anthropized environments.

Bluetongue disease in sheep: a review / O vírus da língua azul em ovinos: uma revisão

The present review aims to show the main aspects related to bluetongue virus (BTV) infection in sheep. The bluetongue (BT) is a viral, infectious, and non-contagious disease caused by a virus (BTV) of the Orbivirus genus, transmited by a hematophagous vector of the Culicoides genus, to domestic and wild ruminants, mainly to sheep, the most susceptible species. It is caused by the association of endemic with climate conditions, with high temperatures and humidity. Economic loss is directly linked to death, abortion, weight loss, loss of milk, and meat production, and, indirectly, to the restriction on the export of animals and their by-products. The study concludes that the BTV is worldwidely spread, and probably persists due to the warm and humid climate that leads to the proliferation of Culicoides sp., being necessary to adopt measures that reduce the risk factors associated to the BTV infection.(AU)

A presente revisão objetivou apresentar os principais aspectos relacionados à infecção causada pelo vírus da língua azul em ovinos. A língua azul é uma doença viral, infecciosa e não contagiosa, causada por um vírus (BTV) do gênero Orbivírus, transmitida por meio de vetores hematófagos do gênero Culicoides a ruminantes domésticos e selvagens, principalmente aos ovinos, a espécie mais susceptível. A infecção ocorre de forma endêmica, associada a condições climáticas com elevada temperatura e umidade. As perdas econômicas estão ligadas diretamente à morte, ao abortamento, à perda de peso, à perda na produção de leite e carne, e, indiretamente, devido à restrição na exportação de animais e seus subprodutos. O estudo conclui que a língua azul está disseminada mundialmente e persiste, provavelmente, devido ao clima quente e úmido que propicia a proliferação de Culicoides sp., sendo necessário adotar medidas que diminuam os fatores de risco associados à infecção pelo vírus.(AU)

Serosurvey of bluetongue, caprine arthritis-encephalitis (CAE) and Maedi-Visna in Barbary sheep (Ammotragus lervia) of a southern Brazilian zoo / Estudo sorológico dos vírus da língua azul, da artrite-encefalite caprina e Maedi-Visna em aoudads (Ammotragus lervia) em um zoológico do Sul do Brasil

Bluetongue (BT) is an infectious and non-contagious disease of compulsory notification which may affect domestic and wild ruminants, transmitted by Culicoides spp. midges. Despite the high morbidity and mortality in sheep, role of wild animals in the BT cycle remains unclear. Caprine arthritis-encephalitis (CAE) and Maedi-Visna virus (MVV) have been reportedly found in goats and sheep, but not described in wildlife species. Accordingly, serum samples from 17 captive Barbary sheep (Ammotragus lervia) from Curitiba zoo, southern Brazil, were tested for bluetongue, caprine arthritis-encephalitis (CAE) and Maedi-Visna viruses by agar gel immunodiffusion (AGID) and enzyme linked immunosorbent assay (ELISA). Antibodies for bluetongue were observed in 6/17 (35.3%) Barbary sheep by AGID test and in 7/17 (41.2%) by ELISA. All samples were negative for the presence of antibodies against caprine arthritis-encephalitis (CAE) and Maedi-Visna viruses. These findings indicate that Barbary sheep may be infected by bluetongue virus and act as wildlife reservoir in both captive and free-range environments.(AU)

A língua azul é uma doença infecciosa e não contagiosa, de notificação obrigatória, que pode afetar ruminantes domésticos e silvestres, transmitida por mosquitos do gênero Culicoides spp. Apesar da alta morbidade e mortalidade em ovelhas, o papel de animais silvestres no ciclo do vírus da língua azul é desconhecido. A artrite encefalite caprina (CAE) e Maedi-visna vírus (MVV) tem sido encontrados em cabras e ovelhas, porém não há descrição em espécies selvagens. Amostras de soro de 17 aoudads (Ammotragus lervia), mantidos em cativeiro no Zoológico de Curitiba, Sul do Brasil, foram testadas para os vírus da língua azul, da artrite encefalite caprina (CAE) e Maedi-visna, utilizando imunodifusão em gel de ágar e o teste de ELISA (enzyme linked immunosorbent assay). Foram observados anticorpos para o vírus da língua azul em 35,3% (6/17) aoudads utilizando a imunodifusão em gel de ágar e 41,2% (7/17) no ELISA. Todas as amostras foram negativas para a presença de anticorpos contra os vírus da artrite encefalite caprina e Maedi-visna. Esses resultados indicam que os aoudads podem ser infectados pelo vírus da língua azul e atuar como um reservatório silvestre tanto em cativeiro quanto em vida livre.(AU)

Yungahelea, a new genus of predaceous midge from northwestern Argentina (Culicomorpha: Ceratopogonidae)

ABSTRACT A new monotypic genus and species of predaceous midge from the southernmost area of the Argentinean Yungas, Yungahelea australis Spinelli and Ronderos, is described and illustrated from male and female adults. It belongs to a group containing the Ceratopogonini genera Parabezzia Malloch, Diaphanobezzia Ingram and Macfie, Spinellihelea Borkent, Grogan and Picado, Leptohelea Wirth and Blanton, and Fittkauhelea Wirth and Blanton. Phylogenetic interpretation indicates that Yungahelea is the sister group of Spinellihelea or the clade composed by Parabezzia and Diaphanobezzia.

Analysis of Five Arboviruses and Culicoides Distribution on Cattle Farms in Jeollabuk-do, Korea

Arthropod-borne viruses (Arboviruses) are transmitted by arthropods such as Culicoides biting midges and cause abortion, stillbirth, and congenital malformation in ruminants, apparently leading to economic losses to farmers. To monitor the distribution of Culicoides and to determine their relationship with different environmental conditions (temperature, humidity, wind speed, and altitude of the farms) on 5 cattle farms, Culicoides were collected during summer season (May-September) in 2016 and 2017, and analyzed for identification of species and detection of arboviruses. About 35% of the Culicoides were collected in July and the collection rate increased with increase in temperature and humidity. The higher altitude where the farms were located, the more Culicoides were collected on inside than outside. In antigen test of Culicoides against 5 arboviruses, only Chuzan virus (CHUV) (2.63%) was detected in 2016. The Akabane virus (AKAV), CHUV, Ibaraki virus and Bovine ephemeral fever virus (BEFV) had a positive rate of less than 1.8% in 2017. In antigen test of bovine whole blood, AKAV (12.96%) and BEFV (0.96%) were positive in only one of the farms. As a result of serum neutralization test, antibodies against AKAV were generally measured in all the farms. These results suggest that vaccination before the season in which the Culicoides are active is probably best to prevent arbovirus infections.

Biting midges (Diptera: Ceratopogonidae) from an urban forest fragment in Central Amazon (Brazil): Effects of opening areas on abundance, richness, and composition

ABSTRACT We assessed the immature stages of Ceratopogonidae (Diptera) in artificial containers in an urban forest fragment in Manaus (Brazil), including their behavioral, biological and ecological information. In addition, we evaluated the effects of deforestation in an open and forested area on Ceratopogonidae communities. Immatures were sampled between August 2012 and July 2014 in artificial containers installed in both habitat types. We collected 685 immatures of seven morpho-species of Bezzia Kieffer, Culicoides Latreille, Dasyhelea Kieffer, Forcipomyia Meigen, and Palpomyia Meigen. In the open area, we recorded higher temperature and electrical conductivity values than in the forested area; however, these variables did not differ between seasons. Water volume was higher in open area and in rainy season, while pH was similar in both areas and seasons. Species richness was higher in forested area, but did not differ between seasons. We did not record differences in abundance between areas or seasons. Community composition differed between areas, but not between seasons. We provide the first records of Culicoides (Hoffmania) insignis Lutz and C. (Haematomyidium) quasiparaensis Clastrier in artificial containers from the state of Amazonas. Our results suggest that the preservation of forested areas in Amazonas is fundamental for the maintenance of the life cycle of some species of Ceratopogonidae.

Dermatite alérgica à picada de Culicoides em muar: relato de caso / Allergic dermatitis due to bite of Culicoides in muar: case report

A dermatite alérgica à picada de ectoparasitos é uma enfermidade alergoparasitária bastante comum entre animais domésticos, sendo relatada principalmente em pequenos ruminantes e em animais de companhia. Contudo, a doença é pouco diagnosticada na clínica de equídeos devido a similaridades nosológicas com outras dermatopatias. Objetivou-se, com este relato de caso, descrever a síndrome clínica, o plano diagnóstico e a conduta terapêutica de um muar acometido por essa enfermidade. Atendeu-se, no Hospital Veterinário da Universidade Federal Rural do Pernambuco, uma mula de oito anos de idade, que apresentava lesões cutâneas pápulo-crostosas e pruriginosas com evolução clínica de dois anos. Em três situações anteriores, a doença havia sido tratada como dermatite fúngica por outros médicos veterinários. Para o diagnóstico, foram solicitados exame citopatológico e parasitológico de pele, cultivo bacteriológico e fúngico, análise histopatológica e hemograma. Os exames demonstraram uma dermatite superficial perivascular eosinofílica crônica, sendo indicada a terapia tópica com dimetilsufóxido, sulfadiazina, ureia e vitamina A. O protocolo terapêutico mostrou-se satisfatório, permitindo completa remissão do quadro clínico. Este trabalho relatou achados clínicos e patológicos da dermatite alérgica à picada de Culicoides spp. em muar, além de alertar sobre a importância de exames complementares para a realização do diagnóstico diferencial e para o direcionamento terapêutico adequado.(AU)

Allergic dermatitis to ectoparasite bites is a common parasitic disease among domestic animals, being reported mainly in small ruminants and companion animals. However, the disease is poorly diagnosed in equine clinics due to nosological similarities with other skin diseases. The aim of this case report was to describe the clinical syndrome, the diagnostic plan and the therapeutic management of a mule affected by this disease. An 8-year-old mule was observed at Universidade Federal Rural de Pernambuco, presenting papular-crusted and pruritic cutaneous lesions with clinical evolution of two years. In three previous situations, the disease had been treated as fungal dermatitis by other veterinarians. For the diagnosis, cytopathological and parasitological examination of the skin, bacteriological and fungal culture, histopathological analysis and blood count were performed. The exams showed a chronic eosinophilic perivascular superficial dermatitis. A topical therapy with dimethyl sulfoxide, sulfadiazine, urea, and vitamin A was indicated. The therapeutic protocol was satisfactory, allowing complete remission of the clinical condition. This work reported clinical and pathological findings of allergic dermatitis to the bites of Culicoides spp. in muar, in addition to alerting about the importance of complementary examinations for the accomplishment of the differential diagnosis and adequate therapeutic orientation.(AU)

Allergic dermatitis caused by Culicoides in Texel sheep in the state of Pará, Brazil / Dermatite alérgica causada por Culicoides em ovinos Texel no estado do Pará

Allergic dermatitis was studied at a farm located in the municipality of Castanhal in the state of Pará, Brazil, from December 2009 to December 2012. Clinical and epidemiological data were obtained during monthly visits to the farm. Skin biopsies were performed for histopathological examinations, and insects were captured with Centers for Disease Control and Prevention (CDC) traps and live-bait entomological vacuum devices. The property housed a herd of both genders, with 45 Santa Inês sheep of different ages and 72 Texel adults. Of the 72 Texel sheep, 56 were affected. Of these, 24 exhibited alopecia, erythema, edema, and crust in the ears, on top of the head, and less often, around the eyes. In addition to the lesions described above, 14 animals exhibited hyperpigmentation of the ears and/or around the eyes and crust in the nose. Another 18 animals exhibited chronic lesions characterized by deformed and thickened ears, alopecia with hyperpigmentation, and in most cases, secondary bacterial infections with abscesses and/or myiasis. Some of these animals had lost part of their ears. Histologically, the lesions were characterized as orthokeratotic hyperkeratosis, acanthosis, vacuolization, and necrosis of epidermal cells. An inflammatory infiltrate was present in the dermis, which was composed mainly of eosinophils and macrophages, some lymphocytes and mast cells, and few neutrophils, in addition to edema and collagen deposition. The Santa Inês sheep were not affected. Among the captured insects, 294 specimens of Culicoides (Hoffmania) plaumanni Spinelli, 57 specimens of C. (Hoffmania) insignis Lutz, and 27 specimens of other Culicoides species were identified. We conclude that C. plaumanni, C. insignis, and possibly other Culicoides species are involved in the etiology of allergic dermatitis in Texel sheep in the state of Pará. Santa Inês sheep in the same region and under the same conditions were not affected, which suggests lower susceptibility of these animals.(AU)

A doença foi estudada em uma propriedade localizada no município de Castanhal, Pará, no período de dezembro de 2009 a dezembro de 2012. A propriedade possuía um plantel de 117 ovinos, 45 da raça Santa Inês e 72 Texel. Dos 72 ovinos da raça Texel, 56 estavam afetados. Os principais sinais clínicos observados foram alopecia, eritema, edema, hiperpigmentação e crostas nas orelhas, parte superior da cabeça e ao redor dos olhos. Em alguns animais as orelhas estavam deformadas, espessadas e com abscessos e/ou miíase. Histologicamente, as lesões caracterizavam-se por hiperqueratose ortoqueratótica, acantose, vacuolização e necrose das células da epiderme. Na derme havia infiltrado inflamatório composto principalmente por eosinófilos e macrófagos, edema e deposição de colágeno. Entre os insetos capturados foram identificados 294 exemplares de Culicoides (Hoffmania) plaumanni Spinelli, 57 de Culicoides (Hoffmania) insignis Lutz e 27 exemplares pertencentes a outras espécies de Culicoides. Conclui-se que C. plaumanni, C. insignis e, possivelmente, outras espécies de Culicoides estejam envolvidos na etiologia da dermatite alérgica nos ovinos da raça Texel no estado do Pará. Ovinos da raça Santa Inês que se encontravam na mesma área e nas mesmas condições não foram afetados, sugerindo menor susceptibilidade.(AU)

Description of fourth instar larva and pupa of Atrichopogon delpontei Cavalieri and Chiossone (Diptera: Ceratopogonidae) from Brazilian Amazonia

ABSTRACT The fourth instar larva and pupa of Atrichopogon delpontei Cavalieri and Chiossone are described for the first time. The immatures were collected from stream margins in the northern Brazilian states Rondônia and Piauí, and subsequently reared to adults. Larvae and pupae are illustrated and photomicrographed. Details on the rearing process and feeding behavior in laboratory, bionomics and notes on habitats are also provided.

Species Diversity and Seasonal Distribution of Culicoides spp. (Diptera: Ceratopogonidae) in Jeju-do, Republic of Korea

Biting midges belonging to the genus Culicoides (Diptera: Ceratopogonidae) were collected by Mosquito Magnet(R) and black light traps at 5 sites on Jeju-do, Republic of Korea (Korea), from May-November 2013 to determine species diversity and seasonal distribution. A total of 4,267 specimens were collected, of which 99.9% were female. The most common species was Culicoides tainanus (91.8%), followed by C. lungchiensis (7.2%) and C. punctatus (0.6%), while the remaining 4 species accounted for <0.5% of all Culicoides spp. that were collected. High numbers of C. tainanus were collected in May, followed by decreasing numbers through August, and then increasing numbers through November when surveillance was terminated. Peak numbers of C. lungchiensis were collected during September, with low numbers collected from May-August and October-November. The presence of C. lungchiensis in Korea was confirmed by morphological and molecular analyses.

Mansonelliasis, a neglected parasitic disease in Haiti

Reported in Haiti as early as 1923, Mansonella ozzardi is still a neglected disease ignored by the health authorities of the country. This review is an update on the geographic distribution of the coastal foci of mansonelliasis in Haiti, the epidemiological profile and prevalence rates of microfilariae in people living in endemic areas, the clinical impact of the parasite on health and the efficiency of the transmission of the parasite among three Culicoides biting-midge species identified as vectors in Haiti. Additionally, interest in establishing a treatment programme to combat this parasite using a single dose of ivermectin is emphasised.

Seasonal Abundance of Culicoides (Diptera: Ceratopogonidae) Collected by Mosquito Magnet(R) in Northern Gyeonggi-do (Province), Korea

Biting midges (Culicoides: Ceratopogonidae) were collected by Mosquito Magnet(R) traps at the Neutral Nations Supervisory Commission (NNSC) camp and Daeseongdong village inside the demilitarized zone (DMZ) and near the military demarcation line (MDL) separating North and South Korea and at Warrior Base (US Army training site) and Tongilchon 3 km south of the DMZ in northern Gyeonggi Province, Republic of Korea (ROK), from May-October 2010-2012, to determine their seasonal distributions. A total of 18,647 Culicoides females (18,399; 98.7%) and males (248; 1.3%) comprising 16 species were collected. Overall, the most commonly collected species was Culicoides nipponensis (42.9%), followed by C. erairai (29.2%), C. punctatus (20.3%), C. arakawae (3.3%), C. pallidulus (1.8%), and C. circumscriptus (1.4%), while the remaining 10 species accounted for only 1.1% of all Culicoides spp. collected. The seasonal distribution of C. nipponensis was bimodal, with high numbers collected during May-June and again during September. C. erairai was more frequently collected during June-July, followed by sharply decreased populations from August-October. C. punctatus was collected in low numbers from May-September with high numbers collected during October. C. erairai was predominantly collected from the NNSC camp (85.1% of all C. erairai collected) located adjacent to the MDL at Panmunjeom in the northernmost part of Gyeonggi-do (Province), while other sites yielded low numbers of specimens.

Two new species and new records of biting midges of the genus Culicoides from northwestern Argentina (Diptera: Ceratopogonidae)

The following two new species of Culicoides from the Argentinean Yungas are described, illustrated and placed to subgenus or species group and compared with related congeners: Culicoides calchaqui Spinelli & Veggiani Aybar and Culicoides willinki Spinelli & Veggiani Aybar. Culicoides daedaloides Wirth & Blanton is recorded for the first time for Argentina and Culicoides pseudoheliconiae Felippe-Bauer is firstly mentioned from the northwestern region of the country.

New Culicoides Latreille of the subgenus Mataemyia Vargas from Pará, Brazil (Diptera: Ceratopogonidae)

Two new species of Culicoides Latreille of the Neotropical subgenus Mataemyia Vargas are described and illustrated based on female specimens from Juruti, Pará, Brazil and compared with their similar congeners. This paper also presents a diagnosis of the subgenus Mataemyia and a systematic key for the identification of the 19 species of the subgenus.

Abundance of biting midge species (Diptera: Ceratopogonidae, Culicoides spp.) on cattle farms in Korea

Culicoides biting midges were collected on three cattle farms weekly using light traps overnight from May to October between 2010 and 2011 in the southern part of Korea. The seasonal and geographical abundance of Culicodes spp. were measured. A total of 16,538 biting midges were collected from 2010 to 2011, including seven species of Culicoides, four of which represented 98.42% of the collected specimens. These four species were Culicodes (C.) punctatus (n = 14,413), C. arakawae (n = 1,120), C. oxystoma (n = 427), and C. maculatus (n = 318). C. punctatus was the predominant species (87.15%).

Dermatite alérgica sazonal em ovinos deslanados no nordeste do Brasil / Sazonal allergic dermatitis in hair sheep from northeastern Brazil

Dermatite alérgica sazonal foi diagnosticada em um rebanho de 40 ovinos da raça Santa Inês no município de Jucurutú, Estado de Rio Grande do Norte. Para o estudo epidemiológico e observação dos sinais clínicos a propriedade foi visitada periodicamente entre 2007 e 2010. Os ovinos eram criados extensivamente em campo nativo cortado pelo rio Piranhas e com um açude permanente. Entre 2007 e 2009 adoeceram 13 (32,5%) ovinos de um total de 40. As lesões eram observadas durante a época da chuva e regrediam total ou parcialmente durante a seca, reaparecendo no próximo período chuvoso. Os animais que foram retirados da área se recuperaram. No final de 2009 foram eliminados os animais susceptíveis e três novos casos apareceram em 2010. A pele apresentava lesões alopécicas, crostosas, enrugadas, esbranquiçadas e com intenso prurido, localizados na região da cabeça (orelhas, ao redor dos olhos e região frontal), região dorsal do corpo e garupa. Histologicamente, a epiderme apresentou hiperqueratose, acantose, hipergranulose e moderada espongiose. Na derme havia infiltrado inflamatório, principalmente perivascular, composto por eosinófilos, macrófagos e plasmócitos. Observou-se queratose de folículos pilosos e dilatação das glândulas sudoríparas. No hemograma, os valores de todos os animais estavam dentro dos valores normais. Em abril e junho de 2010 foram realizadas capturas de insetos com armadilhas luminosas CDC, sendo 110 dípteros capturados, dos quais 43 foram identificados como Culicoides insignis Lutz. Considerando que esta espécie tem sido associada à dermatite alérgica em outras regiões conclui-se que a doença é uma dermatite alérgica sazonal associada à picada de C. insignis.

Seasonal allergic dermatitis is reported in a flock of 40 hair sheep of the Santa Inês breed, in the county of Jucurutú, State of Rio Grande do Norte, in the semiarid region of Northeastern Brazil. For the epidemiologic and clinical observations the farm was visited periodically from 2007 to 2010. The flock was raised extensively in a Paddock crossed by the Piranhas river, and had also a permanent pond. Between 2007 and 2009, 13 (32.5%) sheep out of 40 were affected. The lesions were observed during the raining season, regressed total or partially during the dry season, and reappeared in the next raining period. Sheep removed to other region recovered. At the end of 2009, all affected sheep were removed from the flock. Three new cases appeared in 2010. The skin of the affected sheep was whitish, irregularly thickened, with alopecia, crusts, and intense pruritus. Those lesions were localized more frequently in the head (ears and periocular and frontal regions) but in some animals the dorsum and croup were also affected. Histologic lesions of the epidermis were hyperkeratosis, acanthosis, hypergranulosis, and moderate spongiosis. The dermis showed infiltration by eosinophils, macrophages and plasma cells, mainly perivascular. The hair follicles showed keratosis and the sudoriparous glands were dilated. No changes were observed in the differential blood count. In April and June 2010 insects were captured by the use of CDC light trap. Forty three out of 110 dipterous captured were identified as Culicoides insignis Lutz. It is concluded that the disease is a seasonal allergic dermatitis associated with C. insignis bites.

Seasonal Abundance of Biting Midges, Culicoides spp. (Diptera: Ceratopogonidae), Collected at Cowsheds in the Southern Part of the Republic of Korea

Black light traps were used to measure the seasonal and geographical distribution of Culicoides spp. (biting midges or no-see-ums) at 9 cowsheds in the southern half of the Republic of Korea (ROK) from June through October 2010. A total of 25,242 Culicoides females (24,852; 98.5%) and males (390; 1.5%) comprising of 9 species were collected. The most commonly collected species was Culicoides punctatus (73.0%) followed by C. arakawae (25.7%), while the remaining 7 species accounted for <1.0% of all Culicoides spp. collected. The mean number of Culicoides spp. collected per trap night (Trap Index [TI]) was highest for C. punctatus (409.3), followed by C. arakawae (144.2), C. tainanus (4.1), C. oxystoma (1.2), C. circumscriptus (0.7), C. homotomus (0.6), C. erairai (0.4), C. kibunensis (0.3), and C. nipponensis (0.04). Peak TIs were observed for C. punctatus (1,188.7) and C. arakawae (539.0) during July and August, respectively. C. punctatus and C. arakawae have been implicated in the transmission of arboviruses and other pathogens of veterinary importance that adversely impact on animal and bird husbandry.

Línea básica de susceptibilidad y efecto sinérgico a los insecticidas malation y pirmifos-metil en adultos de Culex spp. Say, 1823 (Díptera: Culicidae) del municipio Mario Briceño Iragorry del estado Aragua, Venezuela / Baseline susceptibility and synergistic effect to the insecticides malathion and pirmiphos-methyl in adults of Culex spp. Say, 1823 (Diptera: Culicidae) Mario Briceño Iragorry municipality, Aragua state, Venezuela

Se evaluó la respuesta a los insecticidas organofosforados malatión y pirimifos-metil en poblaciones de campo de adultos Culex spp. del Municipio Mario Briceño Iragorry del Estado Aragua. Se realizaron los bioensayos en botellas tratadas con insecticidas. La determinación del tiempo-mortalidad, permitió obtener la línea base de susceptibilidad de los insecticidas evaluados. Se definió la dosis diagnóstica como la menor dosis que mata el mayor porcentaje de los insectos expuestos. El número de sobrevivientes a los 60 minutos de exposición a dichas dosis fue considerado como criterio de resistencia definiéndose dicho tiempo, como el umbral de resistencia. Los mosquitos resultaron resistentes a malatión a las concentraciones 0,1; 1 y 5 μg/mL con valores de TL100= 90; 90 y 75 minutos respectivamente y susceptibles a pirimifos-metil a las concentraciones 1 y 5 μg/mL con valores TL100= 30 y 15 minutos respectivamente, a la concentración 0,1 μg/mL se obtuvo TL100= 75 lo cual no se estimó por ser una dosis baja. Las concentraciones 5 μg/mL de malatión, 0, μg/ml de pirimifos-metil se sugieren como dosis referenciales. Se identificaron mecanismos de resistencia con el sinergista butóxido de piperonilo (PB) a las concentraciones de malatión 1 y 5 μg/mL con FS = 2 y 2,5 respectivamente. Las enzimas de multifunción oxidasa (MFO) juegan un papel importante en la resistencia al insecticida malation. Los resultados obtenidos, aportan información básica para futuros programas de control de Culex spp., si fuese necesario, debido a su importancia como plaga de ambientes turísticos y como vector de Filariasis (bancroftiasis) y Fiebre del Nilo.

We evaluated the response to the organophosphorus insecticides malathion and pirimiphos-methyl in field populations of adult Culex spp. Mario Briceño Iragorry Municipality Aragua state. Bioassays were carried out using the bottles treated with insecticides. The time-mortality determination allowed us to obtain the baseline susceptibility of the insecticides evaluated. Diagnostic dose was defined as the lowest dose that kills the highest percentage of exposed insects. Survivors after 60 minutes of exposure to these doses was considered as resistance criterion defining this time, as the threshold of resistance. The mosquitoes were resistant to malathion at concentrations 0.1; 1 and 5 μg/mL with values of TL100= 90; 90 and 75 minutes respectively and susceptible to pirimiphos-methyl at concentrations 1 and 5 μg/mL with values of TL100= 30 and 15 minutes respectively, was obtained at the concentration 0.1 μg /mL TL100= 75 which was not considered to be a low dose. The concentrations 5 μg /mL of malathion, 0.1 μg / ml of pirimiphos-methyl are suggested as a reference dose. Resistance mechanisms were identified with the synergist piperonyl butoxide (PB) at concentrations of malathion 1 and 5 μg/mL with FS = 2 and 2.5 respectively. Multifunction oxidase enzymes (MFO) play an important role in resistance to the insecticide malathion. The obtained results provide basic information for future monitoring programs of Culex spp, if necessary, due to its importance as a pest of tourist environments and as a vector of Filariasis (bacroftiosis) and West Nile Fever.