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^® 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.     

荒川库蠓rDNA ITS2的序列测定与分析

库蠓种类繁多,给人畜健康带来巨大危害.荒川库蠓(Culicoides arakawae)是卡氏住白虫的重要传播媒介,引起鸡的卡氏住白虫病,导致蛋鸡产蛋量下降、肉鸡体重下降甚至死亡(Li et al.,2000),给养鸡业带来巨大经济损失.如何对各种媒介库蠓进行正确的区分或鉴定,是摆在各位寄生虫学家面前的具体问题.目前,寄生虫的分类鉴别主要依据形态学特征,一旦遇到形态学相似的近缘种就非常棘手.     

Impacts of climate, host and landscape factors on Culicoides species in Scotland

Culicoides biting midges (Diptera: Ceratopogonidae) vector a wide variety of internationally important arboviral pathogens of livestock and represent a widespread biting nuisance. This study investigated the influence of landscape, host and remotely-sensed climate factors on local abundance of livestock-associated species in Scotland, within a hierarchical generalized linear model framework. The Culicoides obsoletus group and the Culicoides pulicaris group accounted for 56% and 41%, respectively, of adult females trapped. Culicoides impunctatus Goetghebuer and C. pulicaris s.s. Linnaeus were the most abundant and widespread species in the C. pulicaris group (accounting for 29% and 10%, respectively, of females trapped). Abundance models performed well for C. impunctatus, Culicoides deltus Edwards and Culicoides punctatus Meigen (adjusted R(2) : 0.59-0.70), but not for C. pulicaris s.s. (adjusted R(2) : 0.36) and the C. obsoletus group (adjusted R(2) : 0.08). Local-scale abundance patterns were best explained by models combining host, landscape and climate factors. The abundance of C. impunctatus was negatively associated with cattle density, but positively associated with pasture cover, consistent with this species' preference in the larval stage for lightly grazed, wet rush pasture. Predicted abundances of this species varied widely among farms even over short distances (less than a few km). Modelling approaches that may facilitate the more accurate prediction of local abundance patterns for a wider range of Culicoides species are discussed.     

Culicoides aspirated from cattle in Costa Rica, Honduras, Panama and Puerto Rico, and their role as potential vectors of bluetongue viruses

Abstract. In 1991, as part of an epidemiological study of bluetongue viruses (BTV) in the Central American and Caribbean region, eight farms located in Costa Rica, Honduras, Panama and Puerto Rico were sampled for Culicoides spp. attacking cattle. Using cattle bait, 3884 biting midges were collected with an electric aspirator during both crepuscular periods. The predominant species captured was Culicoides insignis Lutz (95%), followed by C.furens (Poey) (3.4%), C.filarifer Hoffman/ C.ocumarensis Ortiz (0.9%), C.lahillei (Iches) (0.7%), C.arubae Fox and Hoffman (<0.1%) and C.gorgasi Wirth and Blanton (<0.1%). Blood-engorged specimens from some of these species were collected and comprised: 18% of all C.insignis , 36% of C.furens , 37% of filarifer/ocumarensis and 25% of C.lahillei. No engorged C.arubae or C.gorgasi were caught. These results confirm earlier findings pointing to C.insignis, C.furens and C.filarifer/ ocumarensis as potential vectors of BTV in the region.     

Ticks collected from selected mammalian hosts surveyed in the Republic of Korea during 2008-2009

A tick survey was conducted to determine the relative abundance and distribution of ticks associated with selected mammals in the Republic of Korea (ROK) during 2008-2009. A total of 918 ticks were collected from 76 mammals (6 families, 9 species) captured at 6 provinces and 3 Metropolitan Cities in ROK. Haemaphysalis longicornis (54.4%) was the most frequently collected tick, followed by Haemaphysalis flava (28.5%), Ixodes nipponensis (7.6%), Ixodes pomerantzevi (4.8%), Ixodes persulcatus (4.6%), and Haemaphysalis japonica (0.1%). Adults (57.0%) and nymphs (28.7%) of Ixodes and Haemaphysalis spp. were collected most frequently from medium or large mammals in this survey, while few larvae (14.3%) were collected. Hydropotes inermis was the most frequently captured mammal (52.6%), with a 16.4 tick index and 5 of 6 species of ticks collected during this survey. H. longicornis (69.7%) was the predominant tick collected from H. inermis, followed by H. flava (22.2%), I. persulcatus (6.1%), I. nipponensis (1.8%), and H. japonica (0.2%).     

库蠓亚属6种库蠓翅形变化分析及亲缘关系探讨

本研究基于几何形态学测量分析方法对库蠓亚属6种库蠓(渐灰库蠓Culicoides grisescens、光胸库蠓Culicoides impunctatus、日本库蠓Culicoides nipponensis、灰黑库蠓Culicoides pulicaris、刺螫库蠓Culicoides punctatus、天祥库蠓Culicoides tienhsiangensis)的翅脉形态进行定量分析,以探讨6种库蠓种间的亲缘关系。首先对库蠓亚属6种、24头标本翅脉使用几何形态学标点法标记12个地标点,并通过普氏叠加、典型变量分析法、聚类分析法等对6种库蠓翅进行比较分析以及种间亲缘关系探讨。结果显示,翅形变化与亲缘关系结果一致,即6种库蠓的翅形均有显著差异(P<0.05),其中光胸库蠓和渐灰库蠓的翅形变化最小,亲缘关系最近,而日本库蠓与其他5种库蠓的翅形变化最大,亲缘关系最远。初步证实了几何形态学能够做为一种辅助工具对蠓科昆虫进行种间关系及分类研究。     

五种库蠓脂肪酸的研究

本文用气相色语法分析了不显库蠓(Culicoides obsoletus)、兴安库蠓(C, sinanoensis)、怒江库蠓(C.Nujiangensis)、灰黑库蠓(C.Pulicaris)和刺整库蠓(C.Punctatus)等5种库蠓雌虫脂 肪醛的组成和含量。 结果表明,5种库蠓均含有12-14种主要脂肪酸,并以棕榈油酸(C_16：1)、棕搁酸 (C_16：0)、油酸(C_18：1)、硬脂酸(C_18：0)含量最高,共占脂肪酸总量的70%以上。对主要脂肪酸的含量进行聚类分析,发现不显库蠓种团内任意两种库蠓间的欧氏距离小于不显库蠓种团种类与灰黑库蠓种团种类间的欧氏距离,说明脂肪酸的定性、定量分析结果对库蠓分类有一定的参考价值。     

Equine Culicoides hypersensitivity in Florida: biting midges aspirated from horses

Nine species of Culicoides were aspirated from horses in Florida during the second phase of a study of equine Culicoides hypersensitivity (CHS). Approximately 90% of the 2933 midges were Culicoides insignis Lutz, 4% were C.stellifer (Coquillett), 3% were C.niger Root and Hoffman, 2% were C.alachua Jamnback and Wirth and the remaining 1% included C.venustus Hoffman, C.scanloni Wirth and Hubert, C.lahillei Iches (= C.debilipalpis Lutz), C.pusillus Lutz, and C.edeni Wirth and Blanton. Culicoides were sampled on seven farms located throughout Florida. The location and seasonality of lesion development on horses with CHS correlated with the Culicoides spp. collected directly from the horses as to their sites of attack, their seasonality and geographical distribution.     

Spatial and temporal distribution of bluetongue and its Culicoides vectors in Bulgaria

Surveillance of Culicoides (Diptera: Ceratopogonidae) biting midges was carried out between 2001 and 2003, at 119 sites within a 50 x 50-km grid distributed across Bulgaria, using light trap collections around the time of peak adult midge abundance. Sentinel and ad hoc serum surveillance of hosts susceptible to bluetongue infection was carried out at around 300 sites between 1999 and 2003. Following the initial incursion of bluetongue virus 9 (BTV-9) into Bourgas province in 1999, affecting 85 villages along the southern border, a further 76 villages were affected along the western border in 2001, with outbreaks extending as far north as 43.6 degrees N. The BTV-9 strain in circulation was found to have a low pathogenicity for Bulgarian sheep populations, with less than 2% of susceptible individuals becoming sick and seroconversions detected up to 30 km from recorded outbreaks in the south. The major Old World vector Culicoides imicola Kieffer was not detected among over 70,000 Culicoides identified in summer collections, suggesting that BTV-9 transmission in Bulgaria was primarily carried out by indigenous European vectors. The most likely candidates, the Palaearctic species complexes - the Culicoides obsoletus Meigen and C. pulicaris L. complexes - were widespread and abundant across the whole country. The C. obsoletus complex represented 75% of all individuals trapped in summer and occurred in high catch sizes (up to 15,000 individuals per night) but was not found across all outbreak sites, indicating that both Palearctic complexes probably played a role in transmission. Within the C. pulicaris complex, only C. pulicaris s.s., C. punctatus Meigen and C. newsteadi Austen were sufficiently abundant and prevalent to have been widely involved in transmission, whilst within the C. obsoletus complex most trapped males were C. obsoletus s.s. Adult vectors were found to be largely absent from sites in west Bulgaria for a period of at least 3 months over winter, which, taken along with the spatiotemporal pattern of outbreaks in the region between years, indicates the virus may be overwintering here by an alternative mechanism - either by covert persistence in the vertebrate host or possibly by persistence in larval stages of the vector.     

Oral susceptibility of South African stock-associated Culicoides species to bluetongue virus

Field-collected South African Culicoides species (Diptera, Ceratopogonidae) were fed on sheep blood containing bluetongue virus (BTV) represented by 13 low-passage reference serotypes: -1, -2, -4, -6, -7, -8, -9, -10, -11, -12, -13, -16 and -19. After 10 days of extrinsic incubation at 23.5 degrees C, of the 13 serotypes used, seven were recovered from C. (Avaritia) imicola Kieffer and 11 from C. (A.) bolitinos Meiswinkel. Virus recovery rates and the mean titres for most serotypes were significantly higher in C. bolitinos than in C. imicola. In addition, BTV was recovered from three non-Avaritia Culicoides species, namely C. (Remmia) enderleini Cornet & Brunhes (BTV-9), C. (Hoffmania) milnei Austen (BTV-4) and C. (H.) zuluensis de Meillon (BTV-16). No virus could be recovered from 316 individuals representing a further 14 Culicoides species. In Culicoides species fed on blood containing similar or identical virus titres of distinct BTV serotypes, significant differences were found in virus recovery rates. The results of this study confirm the higher vector competence of C. bolitinos compared with C. imicola.     

Seasonal abundance of livestock‐associated Culicoides species in northeastern Brazil

Culicoides biting midges (Diptera: Ceratopogonidae) are of great medical and veterinary importance because the haematophagous females of some species can transmit diseases to humans and animals. In order to determine the presence and seasonal abundance of the bluetongue virus (BTV) vector Culicoides insignis Lutz at domestic animal sheds in northeastern Brazil, insects were collected once a month between January and December 2010. Light traps were set from 18.00 to 06.00 hours at a pigsty, chicken coop and bovine corral. Culicoides insignis accounted for 81% of the 22 316 specimens collected. Other well‐represented species were: Culicoides paucienfuscatus Barbosa (3246 individuals), Culicoides diabolicus Hoffman (308), Culicoides leopoldoi Ortiz (224) and Culicoides duartei Tavares and Luna Dias (221). The remainder accounted for 4% of the total sample. Culicoides insignis occurred mostly at the cattle corral, 98.2% in the rainy season. This study confirms the presence and close association of C. insignis with cattle in Maranhão state, northeastern Brazil and emphasizes the risk of bluetongue infections spreading in the area.     

Light trapping of biting midges Culicoides spp. (Diptera: Ceratopogonidae) with green light-emitting diodes

Abstract  A study of responses by Culicoides spp. to light traps with light-emitting diodes (LEDs) confirmed that the livestock virus vector, Culicoides brevitarsis Kieffer, was preferentially attracted to green light. Four species shown previously to respond to blue light exhibited significantly higher responses to ultraviolet (UV) light. Field trials comparing green LEDs with incandescent lights in New South Wales, Northern Territory and East Timor confirmed the superiority of green LEDs for catching C. brevitarsis . The green LED traps also had a significant advantage over incandescent traps for a wide range of Culicoides species. These included: species whose ultimate preference was for UV, most species that are proven or potential vectors of viruses affecting Australian livestock and native animals and the main species affecting humans in northern Australia. Use of green LEDs has been adopted for trapping C. brevitarsis , especially in its marginal and low-density areas, and for detecting incursions of new Culicoides spp. into Australia. Use could be possible for species in other insect Orders.     

Morphology and DNA barcoding reveal three species in one: description of Culicoides cryptipulicaris sp. nov. and Culicoides quasipulicaris sp. nov. in the subgenus Culicoides

Species of the genus Culicoides (Diptera: Ceratopogonidae) are well known for their importance in the field of medical and veterinary entomology. Culicoides spp. transmit a wide variety of pathogens, primarily viruses that affect animals and humans. In Europe, the most economically important disease transmitted by Culicoides is bluetongue (BT). Culicoides spp. have been recently involved as primary vectors for Schmallenberg disease. The taxonomy within the subgenus Culicoides has been historically difficult and reorganizations have been proposed regularly. The subgenus Culicoides includes species that are considered to be potential vectors for BT. High morphological intraspecific variability has been attributed to these species. This highlights the apparent presence of previously undetected cryptic species diversity in the subgenus. In the present study, a detailed morphological and molecular study of specimens belonging to Culicoides pulicaris s.l. and specimens resembling a cross between C. pulicaris and Culicoides punctatus revealed the presence of two new species: Culicoides cryptipulicaris and Culicoides quasipulicaris. Females of C. quasipulicaris and males of both species were morphologically distinguished from C. pulicaris (Linnaeus, 1758), whereas females of C. cryptipulicaris were identified using molecular techniques exclusively.     

Determination of the oral susceptibility of South African livestock-associated biting midges,Culicoides species,to bovine ephemeral fever virus

A total of 10 607 Culicoides midges (Diptera: Ceratopogonidae) were fed on either sheep or horse blood containing not less than 6.5 log10 TCID50/ml of bovine ephemeral fever virus (BEFV). Insects were collected during two consecutive summers from two distinct climatic areas. Two seed viruses, originating from either South Africa or Australia, were used separately in the feeding trials. Blood-engorged females were incubated at 23.5 degrees C for 10 days and then individually assayed in microplate BHK-21 cell cultures. Of the 4110 Culicoides that survived, 43% were C. (Avaritia) imicola Kieffer and 27% were C. (A.) bolitinos Meiswinkel. The remainder represented 18 other livestock-associated Culicoides species. Although BEFV was detected in 18.9% of midges assayed immediately after feeding, no virus could be detected after incubation. The absence of evidence of either virus maintenance or measurable replication suggests that most of the abundant livestock-associated Culicoides species found in South Africa are refractory to oral infection with BEFV. Future studies should be carried out using species of mosquitoes that are associated with cattle in the BEF endemic areas.     

Habitats of Culicoides spp. in an intertidal zone of southeast Queensland, Australia

The distribution of immature Culicoides Latreille (Diptera: Ceratopogonidae) in the intertidal zone was investigated at Redland Bay near Brisbane, southeast Queensland. The aims of this study were to determine the distribution of Culicoides immatures and to identify environmental factors influencing these distributions. Light trapping of adult midges indicated that C.subimmaculatus Lee & Reye, C.marmoratus (Skuse), C.longior Hagan & Reye, C.henryi Lee & Reye, C.cordiger Macfie, may have been breeding in the study site. Soil sampling on six transects traversing mangrove and salt-marsh revealed the breeding habitats from which immature stages of the first four species were obtained. The elevation, vegetation and soils of positive sites were recorded and analysed for each species of Culicoides. The distribution of intertidal vegetation (mangroves and salt-marsh plants) was compared to MacNae's (1966) system of mangrove zonation for eastern Australia. The distribution of immature Culicoides did not correspond with mangrove zones, but was related to the presence or absence of intertidal vegetation. C.subimmaculatus was closely associated with a particular substrate and the presence of burrowing crabs.     

Prevalence of Zoonotic Trematode Metacercariae in Freshwater Fish from Gangwon-do,Korea

The infection status of zoonotic trematode metacercariae was investigated in a total of 2,293 freshwater fish collected from 11 rivers or streams in 9 administrative regions of Gangwon-do, Korea for 5 years (2009-2013). All fish were collected by netting methods and examined using the artificial digestion methods. Clonorchis sinensis metacercariae were detected in 4 fish species, i.e., Pungtungia herzi, Squalidus japonicus coreanus, Acheilognathus rhombeus, and Ladislabia taczanowskii, from only Hantangang in Cheorwon-gun. Metagonimus spp. metacercariae were found in 1,154 (50.3%) fish and their average number per infected fish was 55.8. Among the positive fish species, especially Tribolodon hakonensis from Namdaecheon in Yangyang-gun and Plecoglossus altivelis from Osipcheon in Samcheok-si were most heavily infected. Centrocestus armatus metacercariae were detected in 611 (26.7%) fish and the average metacercarial burden per infected fish was 1,032. Two chub species, Zacco platypus and Zacco temminckii were highly and heavily infected with C. armatus metacercariae in almost all regions surveyed. Echinostoma spp. metacercariae were also found in 24 fish from a few localities, but their numbers per fish infected were very low. From the above results, it is confirmed that the metacercariae of intestinal flukes, especially Metagonimus spp. and C. armatus, were heavily infected, while C. sinensis metacercariae were rarely found in fish from Gangwon-do, Korea.     

Seroepidemiological Survey of Zoonotic Diseases in Small Mammals with PCR Detection of Orientia tsutsugamushi in Chiggers,Gwangju, Korea

Serosurveillance for zoonotic diseases in small mammals and detection of chiggers, the vector of Orientia tsutsugamushi, were conducted from September 2014 to August 2015 in Gwangju Metropolitan Area. Apodemus agrarius was the most commonly collected small mammals (158; 91.8%), followed by Myodes regulus (8; 4.6%), and Crocidura lasiura (6; 3.5%). The highest seroprevalence of small mammals for O. tsutsugamushi (41; 26.3%) was followed by hantaviruses (24; 15.4%), Rickettsia spp. (22; 14.1%), and Leptospira (2; 1.3%). A total of 3,194 chiggers were collected from small mammals, and 1,236 of 3,194 chiggers were identified with 7 species of 3 genera: Leptotrombidium scutellare was the most commonly collected species (585; 47.3%), followed by L. orientale (422; 34.1%), Euchoengastia koreaensis (99; 8.0%), L. palpale (58; 4.7%), L. pallidum (36; 2.9%), Neotrombicula gardellai (28; 2.3%), and L. zetum (8; 0.6%). L. scutellare was the predominant species. Three of 1,236 chigger mites were positive for O. tsutsugamushi by PCR. As a result of phylogenetic analysis, the O. tsutsugamushi strain of chigger mites had sequence homology of 90.1-98.2% with Boryong. This study provides baseline data on the distribution of zoonotic diseases and potential vectors for the development of prevention strategies of vector borne diseases in Gwangju metropolitan area.