Species diversity and seasonal abundance of Culicoides biting midges in northwestern Argentina

The species diversity and seasonal abundance of biting midges of the genus Culicoides (Diptera: Ceratopogonidae) were studied in northwestern Argentina during the period 2003–2005. A total of 5437 Culicoides specimens were collected using CDC light traps in three areas of the mountainous rainforest area. The most common species were Culicoides paraensis (Goeldi) and C . insignis Lutz, Culicoides lahillei (Iches), C . venezuelensis Ortiz & Mirsa, C . debilipalpis Lutz and C . crescentis Wirth & Blanton were also collected. Culicoides paraensis was abundant during the summer, and C . insignis and C . lahillei during late summer and early fall. Accumulated rainfall was the climatic variable most related to fluctuation in abundance of C . paraensis .     

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.     

A new Culicoides (Diptera:Ceratopogonidae) of the subgenus Diphaomyia from Peru

A new species of Culicoides of the subgenus Diphaomyia, Culicoides jurbergi Felippe-Bauer, is described and illustrated based on female specimens collected biting man and with light traps in Peruvian Amazonia. The species is compared with its similar congener mirsae Ortiz.     

Ecology of Culicoides (Diptera: Ceratopogonidae) in southcentral Florida and experimental Culicoides vectors of the avian hematozoan Haemoproteus danilewskyi Kruse

To determine the vectors of Haemoproteus danilewskyi in blue jays (Cyanocitta cristata) in southcentral Florida (USA), we conducted a 2 yr study from January 1993 to December 1995 of the presence and seasonal abundance of Culicoides spp. Of the 14 species of Culicoides captured in Centers for Disease Control light traps, 10 were ornithophilic. Of these, C. edeni, C. knowltoni, C. stellifer, C. beckae, and C. arboricola were most abundant, representing 46% of the total collection and 99% of the ornithophilic collection. The presence of C. stellifer in Bennett trap collections represents a new biting record for this species on passerine birds. We experimentally challenged the most abundant ornithophilic species to determine which were capable of supporting sporogonic development of H. danilewskyi. Culicoides edeni, C. knowltoni, and C. arboricola supported sporogonic development of H. danilewskyi.     

Biting of anthropophilic Culicoides fulvithorax (Diptera: Ceratopogonidae), a vector of Mansonella perstans in Nigeria

Anthropophilic Culicoides were investigated in a rural community endemic for Mansonella perstans in Ijebu North area of western Nigeria between December 2003 and October 2004. Three hundred and fifty-nine adults of Culicoides fulvithorax collected by human bait in the morning were dissected for Mansonella perstans larvae, and 1.95% of infection rate was found. Seasonal abundance of C. fulvithorax was investigated by monthly biting rates, and showed that higher prevalence was observed in rainy season, with peak in September. Culicoides prevalence was positively correlated with rainfall and relative humidity, but not temperature. Human perceptions on the behavior of these biting midges were determined by interviewing 854 self-selected villagers, of which 86.5% of the interviewees confessed having experienced Culicoides bites. Between 76.5 and 99.1% of the various age groups complained body reactions to Culicoides bites. Itching was the most frequent body reaction. No interviewees associated Culicoides with transmission of any parasitic infections. The results showed need to adequately control Culicoides in the community.     

Bloodmeal analysis reveals avian Plasmodium infections and broad host preferences of Culicoides (Diptera: Ceratopogonidae) vectors

Changing environmental conditions and human encroachment on natural habitats bring human populations closer to novel sources of parasites, which might then develop into new emerging diseases. Diseases transmitted by host generalist vectors are of special interest due to their capacity to move pathogens into novel hosts. We hypothesize that humans using forests for recreation are exposed to a broad range of parasites from wild animals and their vectors. A corollary of this is that new vector-host, parasite-host, and vector-parasite associations could eventually develop. Thus, we expect to observe atypical vector-host associations. Using molecular bloodmeal analysis via amplification of the mtDNA COI gene we identified the vertebrate hosts of Culicoides (Diptera: Ceratopogonidae) species in a sub-urban forest of Southwestern Germany. Bloodmeals were also checked for haemosporidian infections by amplifying a fragment of the mtDNA cyt b gene. We identified a total of 20 Culicoides species, thirteen of which fed on humans. From 105 screened bloodmeals we obtained high quality sequences for 77 samples, 73 (94.8%) originated from humans, two from livestock (Bos taurus and Equus caballus), and two from wild birds (Sylvia atricapilla and Turdus merula). We found that four Culicoides species previously assumed to feed exclusively on either birds (C. kibunensis) or domestic mammals (C. chiopterus, C. deltus, C. scoticus) fed also on humans. A total of six Culicoides abdomens were infected with avian haemosporidian parasites (Plasmodium or Haemoproteus), four of those abdomens contained blood derived from humans. Our results suggest that parasites of wild animals may be transferred to humans through infectious bites of Culicoides vectors. Further, we show that Culicoides vectors believed to be a specialist on specific vertebrate groups can have plastic feeding preferences, and that Culicoides are susceptible to infection by Plasmodium parasites, though vector viability must still be experimentally demonstrated.     

Styloconops hamariensis n. sp. in Somalia (Diptera, Ceratopogonidae)

A new species of the genus Styloconops (S. hamariensis n. sp.) is described on material collected in Somalia in the coastal area near Mogadiscio. This ceratopogonid midge is common during the rainy seasons and it has been observed biting on man and cattle. The new species is morphologically similar to S. spinosifrons from which it can be clearly differentiated for at least some diagnostic characters both in the female and male adults.     

A new Culicoides from the Amazonian region, Brazil (Diptera: Ceratopogonidae)

A new Neotropical species of biting midge Culicoides (Haematomyidium), C. kampa Felippe-Bauer, Veras & Castellon, is described and illustrated based on female specimens from the Amazonian Region.     

Diversity of biting midges of the genus Culicoides Latreille (Diptera: Ceratopogonidae) in the area of the Yacyretá Dam Lake between Argentina and Paraguay

The Culicoides communities have been analyzed between 1993/1998 in the area influenced by the Yacyret Dam Lake (Paran River, Argentina-Paraguay). Adults of Culicoides were collected monthly by using CDC light traps exposed for 24 h in 9 sampling sites located at both margins of the river; 21 species were recorded. Highest values of species richness were recorded during 1993/1994, being Quiteria and Corpus the sites with the higest number of species (10 and 11, respectively). The species diversity was elevated in Quiteria, Zaim n, Candelaria, Santa Tecla, Capit n Meza and Corpus (Shannon's diversity index 1.0-1.9) while Corate , Ituzaing and Aguapey showed less richness and diversity. The more abundant species were C. insignis, C. venezuelensis, C. leopoldoi, C. limai, C. flinti, C. debilipalpis, C. paraensis and C. guttatus. C. insignis, potential vector of bluetongue virus (BTV) to domestic and wild rumiants in the Neotropical region, is the predominant species in the area and was the only species widely distributed. C. paraensis, a proven vector of Oropouche virus to humans, is a common and abundant species. C. pusillus and C. lahillei, potential vectors of BTV and a filarial parasite, respectively, were occasionally collected. The taxonomic structure of communities was constant during the study period. The occasional species were not characteristic to one particular site and their presence could be related to non-intrinsic conditions.     

Characterization of two cryptic species,Culicoides stigma and C.parroti (Diptera: Ceratopogonidae), based on barcode regions and morphology

Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) are insect vectors of economically important veterinary diseases such as African horse sickness, bluetongue, and Schmallenberg virus. The identification of Culicoides based on morphological features can be difficult. Three species of biting midges, Culicoides nubeculosus, C. stigma, and C. parroti have emerged in the laboratory from mud collected around watering troughs on a farm in northern France. Emerging Culicoides were characterized morphologically and molecularly using molecular markers. The closely related species C. stigma and C.parroti showed highly divergent sequences for both mitochondrial (cytochrome B and cytochrome oxidase I) and ribosomal DNA first internal transcribed spacer. A RFLP based on a single restriction using the same enzyme (HaeIII) for both cytochrome C oxidase I and cytochrome B is proposed to identify these species.     

Association of Lutzomyia columbiana (Diptera: Psychodidae) with a leishmaniasis focus in Colombia due to species of the Leishmania mexicana complex.

In Colombia, Leishmania mexicana has a scattered geographical distribution and no sand fly vectors have been associated with its transmission. During the present study, the anthropophilic sand fly Lutzomyia columbiana was found to be the only species collected using diverse methods, in a small focus of Le. mexicana in the municipality of Samaniego, SW Colombia. Ecological data indicate that this sand fly species is present in both peri and intradomestic habitats, where it readily bites man. Further evidence comes from experimental infections of wild-caught Lu. columbiana with Le. mexicana after feeding on infected hamsters. Based on these results, it is suggested that this sand fly is the most likely vector in the study area, suggesting the existence of a previously unknown sand fly-parasite association.     

A morphological investigation of Culicoides spp. biting midges (Diptera: Ceratopogonidae) from the Caribbean.

Features of the antennae, maxillary palps, and mouthparts of the females of seven species of Culicoides spp. biting midges collected from a montane rainforest site in Trinidad, West Indies, were studied by light and scanning electron microscopy. Comparisons were made with two British species, Culicoides impunctatus and Culicoides nubeculosus. Species-specific differences were demonstrated in the camber and pitch of mandibular teeth, the size and shape of the subapical labral sensilla, the size and depth of the palpal sensory pit, and the number and shape of heads of the palpal sensilla. Counts of sensilla coeloconica and palpal sensilla were suggested as being contributory features for the prediction of host preference, indicating that Culicoides darlingtonae, Culicoides glabellus, Culicoides insinuatus, Culicoides paraensis, and Culicoides pseudodiabolicus were probably mammalophilic species. The host preferences of Culicoides heliconiae and Culicoides flavivenula could not be determined accurately.     

Salivary apyrase in New World blackflies (Diptera: Simuliidae) and its relationship to onchocerciasis vector status

Abstract. Salivary gland apyrase is believed to be critical to blood-feeding in arthropod vectors. This enzyme was measured in six New World blackflies representing three taxonomic pairs of non-vectors and vectors of Onchocerca volvulus. In Simulium (Psilopelmia) ochraceum , a highly anthropophilic vector in Mexico and Guatemala, apyrase exhibited maximum activity between pH 8.0 and 9.0, mean 39.8 pM 4.7 milliUnits/pair of gland equivalents (mU), and was enhanced when ATP was used as a substrate. In the zoophilic non-vector Simulium (Psilopelmia) bivittatum maximum activity was significantly less (5.1 pM 0.7 mU) under all conditions examined. Preference for ADP or ATP as substrate was a function of the pH of the reaction for this species. Apyrase activity in Simulium (Simulium) metallicum Bellardi (29.5 pM 11.5 mU), a zoophilic secondary vector in Mexico and Guatemala, resembled that of S.(Ps.)ochraceum (24.8 pM 13.7 mU at pH 8.5) with ADP as substrate, but showed reduced activity with ATP. Both these Central American vectors had higher apyrase activity than found in Simulium (Notolepria) exiguum , a vector of O. volvulus in Ecuador and Colombia. However, maximum apyrase activity, measured at pH 8.0 with ADP as substrate, was greater in S.(N.) exiguum (10.9 pM 0.6mU) than in Simulium (Notolepria) gonzalezi (5.9pM1.9mU), a non-vector species widespread in Central America. Therefore, for the consubgeneric species pairs examined, a positive association was detected between higher concentrations of apyrase activity and their vector status for O. volvulus.     

Detrimental effects of Haemoproteus infections on the survival of biting midge Culicoides impunctatus (Diptera: Ceratopogonidae)

The effects of Haemoproteus belopolskyi, Haemoproteus fringillae, and Haemoproteus lanii on the survival of their vector the biting midge Culicoides impunctatus were examined. Wild-caught females were infected experimentally by allowing them to feed on naturally infected birds. A group of flies, which fed on an uninfected bird, was used as a control. There was a highly significant difference in the survival rate between the noninfected group and all groups of infected flies for postfeeding (PF) periods 1-2, 3-4, 5-6, and 7-8 days. For days 7-8, the percentage of noninfected surviving flies was 4.4 times higher than the percentage of infected surviving flies, testifying to the detrimental effects of avian Haemoproteus infections on the longevity of C. impunctatus. The mortality rates of the infected flies were highest for days 1-2 and 3-4 PF, indicating possible negative effects of ookinetes and early oocysts on the vector.     

The transmission of Haemoproteus belopolskyi (Haemosporida: Haemoproteidae) of blackcap by Culicoides impunctatus (Diptera: Ceratopogonidae)

Haemoproteus belopolskyi of blackcap, Sylvia atricapilla, underwent sporogony in wild-caught female biting midges, Culicoides impunctatus, which were experimentally infected by feeding them on naturally infected birds. The engorged flies were held for 8-12 days to allow development of sporozoites and then aspirated and triturated in 0.85% saline. Seven uninfected nestlings of blackcap at the age of 20-21 days were inoculated into the pectoral muscle with 0.3 ml of the slurry containing approximately 45 sporozoites. Parasitemia of H. belopolskyi developed in 6 nestlings, with a prepatent period of 11-12 days. The maximum parasitemia varied between 0.9 and 16% of erythrocytes in different experimental hosts. Culicoides impunctatus is an experimental vector of H. belopolskyi. It is likely to be the important natural vector of Haemoproteus spp. of passerine birds in Europe.     

The Biting Midge Culicoides sonorensis (Diptera: Ceratopogonidae) Is Capable of Developing Late Stage Infections of Leishmania enriettii

BackgroundDespite their importance in animal and human health, the epidemiology of species of the Leishmania enriettii complex remains poorly understood, including the identity of their biological vectors. Biting midges of the genus Forcipomyia (Lasiohelea) have been implicated in the transmission of a member of the L. enriettii complex in Australia, but the far larger and more widespread genus Culicoides has not been investigated for the potential to include vectors to date.Conclusions/SignificanceWe demonstrate that L. enriettii can develop late stage infections in the biting midge Culicoides sonorensis. This midge was found to be susceptible to L. enriettii to a similar degree as Lutzomyia longipalpis, the vector of Leishmania infantum in South America. Our results support the hypothesis that some biting midges could be natural vectors of the L. enriettii complex because of their vector competence, although not Culicoides sonorensis itself, which is not sympatric, and midges should be assessed in the field while searching for vectors of related Leishmania species including L. martiniquensis and "L. siamensis".