A new species of the Simulium (Gomphostilbia) ceylonicum species-group (Diptera: Simuliidae) from Thailand.

A new black fly species, Simulium (Gomphostilbia) pangsidaense, is described on the basis of adult female, male, pupal exuviae and mature larvae from Pang Sida National Park, Sa Kaew Province, Eastern Thailand. This new species is placed in the Simulium ceylonicum species-group. It is distinguished from three Thai members of the S. ceylonicum species-group by the following characteristics: from S. (G.) curtatum Jitklang et al. and S. (G.) sheilae Takaoka & Davies by the wide pupal terminal hooks (triangular terminal hooks in the latter two species), and from S. (G.) sheilae and S. (G.) trangense Jitklang et al. by the number of male upper-eye facets in 13 vertical columns and 14 or 15 horizontal rows (10 or 11 vertical columns and 12 or 13 horizontal rows in the latter two species). This is the fourth member of the S. ceylonicum species-group recorded from Thailand.

Esperanza Window Traps for the collection of anthropophilic blackflies (Diptera: Simuliidae) in Uganda and Tanzania.

There is an increasing need to evaluate the impact of chemotherapeutic and vector-based interventions as onchocerciasis affected countries work towards eliminating the disease. The Esperanza Window Trap (EWT) provides a possible alternative to human landing collections (HLCs) for the collection of anthropophilic blackflies, yet it is not known whether current designs will prove effective for onchocerciasis vectors throughout sub-Saharan Africa. EWTs were deployed for 41 days in northern Uganda and south eastern Tanzania where different Simulium damnosum sibling species are responsible for disease transmission. The relative efficacy of EWTs and HLCs was compared, and responses of host-seeking blackflies to odour baits, colours, and yeast-produced CO2 were investigated. Blue EWTs baited with CO2 and worn socks collected 42.3% (2,393) of the total S. damnosum s.l. catch in northern Uganda. Numbers were comparable with those collected by HLCs (32.1%, 1,817), and higher than those collected on traps baited with CO2 and BG-Lure (25.6%, 1,446), a synthetic human attractant. Traps performed less well for the collection of S. damnosum s.l. in Tanzania where HLCs (72.5%, 2,432) consistently outperformed both blue (16.8%, 563) and black (10.7%, 360) traps baited with CO2 and worn socks. HLCs (72.3%, 361) also outperformed sock-baited (6.4%, 32) and BG-Lure-baited (21.2%, 106) traps for the collection of anthropophilic Simulium bovis in northern Uganda. Contrasting blackfly distributions were observed on traps in Uganda and Tanzania, indicating differences in behaviour in each area. The success of EWT collections of S. damnosum s.l. in northern Uganda was not replicated in Tanzania, or for the collection of anthropophilic S. bovis. Further research to improve the understanding of behavioural responses of vector sibling species to traps and their attractants should be encouraged.

Onchocerciasis transmission in Ghana: the human blood index of sibling species of the Simulium damnosum complex.

BACKGROUND: Vector-biting behaviour is important for vector-borne disease (VBD) epidemiology. The proportion of blood meals taken on humans (the human blood index, HBI), is a component of the biting rate per vector on humans in VBD transmission models. Humans are the definitive host of Onchocerca volvulus, but the simuliid vectors feed on a range of animals and HBI is a key indicator of the potential for human onchocerciasis transmission. Ghana has a diversity of Simulium damnosum complex members, which are likely to vary in their HBIs, an important consideration for parameterization of onchocerciasis control and elimination models. METHODS: Host-seeking and ovipositing S. damnosum (sensu lato) (s.l.) were collected from seven villages in four Ghanaian regions. Taxa were morphologically and molecularly identified. Blood meals from individually stored blackfly abdomens were used for DNA profiling, to identify previous host choice. Household, domestic animal, wild mammal and bird surveys were performed to estimate the density and diversity of potential blood hosts of blackflies. RESULTS: A total of 11,107 abdomens of simuliid females (which would have obtained blood meal(s) previously) were tested, with blood meals successfully amplified in 3,772 (34 %). A single-host species was identified in 2,857 (75.7 %) of the blood meals, of which 2,162 (75.7 %) were human. Simulium soubrense Beffa form, S. squamosum C and S. sanctipauli Pra form were the most anthropophagic (HBI = 0.92, 0.86 and 0.70, respectively); S. squamosum E, S. yahense and S. damnosum (sensu stricto) (s.s.)/S. sirbanum were the most zoophagic (HBI = 0.44, 0.53 and 0.63, respectively). The degree of anthropophagy decreased (but not statistically significantly) with increasing ratio of non-human/human blood hosts. Vector to human ratios ranged from 139 to 1,198 blackflies/person. CONCLUSIONS: DNA profiling can successfully identify blood meals from host-seeking and ovipositing blackflies. Host choice varies according to sibling species, season and capture site/method. There was no evidence that HBI is vector and/or host density dependent. Transmission breakpoints will vary among locations due to differing cytospecies compositions and vector abundances.

Delineating taxonomic boundaries in the largest species complex of black flies (Simuliidae) in the Oriental Region.

Perspicuous assessments of taxonomic boundaries and discovery of cryptic taxa are of paramount importance in interpreting ecological and evolutionary phenomena among black flies (Simuliidae) and combating associated vector-borne diseases. Simulium tani Takaoka & Davies is the largest and perhaps the most taxonomically challenging species complex of black flies in the Oriental Region. We use a DNA sequence-based method to delineate currently recognized chromosomal and morphological taxa in the S. tani complex on the Southeast Asian mainland and Taiwan, while elucidating their phylogenetic relationships. A molecular approach using multiple genes, coupled with morphological and chromosomal data, supported recognition of cytoform K and morphoform 'b' as valid species; indicated that S. xuandei, cytoform L, and morphoform 'a' contain possible cryptic species; and suggested that cytoform B is in the early stages of reproductive isolation whereas lineage sorting is incomplete in cytoforms A, C, and G.

Avian simuliotoxicosis: outbreak in Louisiana.

From April 20 to May 10, 2010, multiple species of birds were seen at the Louisiana State University (LSU) Zoological Medicine Department for a disease syndrome characterized by acute lethargy, generalized subcutaneous petechiae, vasculitis, and death caused by a black fly identified as Simulium meridionale. Twenty psittacine birds presented with severe depression and multifocal subcutaneous hemorrhages over the body and especially noted in the featherless areas of the head and neck. Ten out of 20 clinical cases seen survived on a treatment regimen consisting of intravenous fluid therapy, anti-inflammatories, antihistaminic medications, and supportive care. The 10 other birds likely died of cardiopulmonary collapse and anaphylactoid reactions. In all post mortem examinations multifocal to coalescing dermal hemorrhage, eosinophilic dermatitis, severe edema, and vasculitis were observed. The LSU School of Animal Science conducted a brief survey that included 34 of the 64 Louisiana parishes and showed that 17 parishes, at least, were affected by this outbreak. A total of at least 225 poultry bird deaths could be attributed to black fly strikes. Simuliotoxicosis outbreaks have previously been reported in North America, and this report documents the clinical and post mortem findings, treatment response, and extent of such an outbreak in pet and farm birds in Louisiana.

Notes on black flies (Diptera: Simuliidae) from North-East India: new records of five species from Arunachal Pradesh and taxonomic reviews of two species from Assam.

In recent surveys of black flies in Arunachal Pradesh, North-East India, five species are newly recorded from Arunachal Pradesh: Simulium (Montisimulium) nemorivagum Datta, 1973, Simulium (Gomphostilbia) darjeelingense Datta, 1973, Simulium (Gomphostilbia) decuplum Takaoka & Davies, 1995, Simulium (Simulium) barnesi Takaoka & Suzuki, 1984 and Simulium (Simulium) pradyai Takaoka & Somboon, 2008, of which the latter three species also represent new records from India. Taxonomic reviews of two species of black flies reported from Assam show that Simulium (Gomphostilbia) unum Datta, 1975 is a junior synonym of Simulium (Gomphostilbia) darjeelingense, and the larva of Simulium (Gomphostilbia) sp. nr. varicorne Edwards is identifiable as Simulium (Gomphostilbia) parahiyangum Takaoka & Sigit, 1992.

Simulium (Gomphostilbia) sofiani, a new species of black fly (Diptera: Simuliidae) from peninsular Malaysia.

Simulium (Gomphostilbia) sofiani sp. nov. is described on the basis of reared adult female, male, pupal and larval specimens collected from Cameron Highlands, Pahang state, Malaysia. This new species is placed in the ceylonicum species-group within the subgenus Gomphostilbia and is easily distinguished from all the related known species by the combination of the following characteristics: an elongate sensory vesicle and yellow hair tuft on the stem vein of the wing in the female, the greater number of large upper-eye facets (15 or 16 vertical columns and 15 or 16 horizontal rows) and almost entirely darkened hind basitarsus in the male, and the gill bearing a long common basal stalk and 8 filaments arranged as [(1+2)+(1+2)] +2 filaments from dorsal to ventral in the pupa.

Investigations into the isolation of the Tukuyu focus of onchocerciasis (Tanzania) from S. damnosum s.l. vector re-invasion.

As part of the feasibility study for an onchocerciasis vector elimination project we investigated the isolation of the Tukuyu focus in Tanzania from possible vector re-invasion. This was achieved by examining the distribution of the Simulium damnosum complex vector cytospecies outside the focus to look for potential sources of re-invasion. Besides cytotaxonomic identifications of the aquatic stages, we applied morphotaxonomic and molecular techniques to identify S. thyolense and confirm it as the anthropophilic species in both the Tukuyu and the neighbouring Ruvuma foci. We detected significant differences in chromosome inversion frequencies between the Tukuyu populations and those breeding to the southwest in the adjacent Songwe river basin and in northern Malawi (where there is no man-biting and no onchocerciasis), suggesting that there is not normally a great deal of migration in either direction. By contrast, populations of S. thyolense from the Tukuyu and Ruvuma foci (150km southeast of Tukuyu) were much more similar in terms of their chromosomal polymorphisms, indicating a higher possibility of re-invasion, although migration is still restricted to some extent, as indicated by some differences in chromosome polymorphisms between the two foci. Future migratory events which might be associated with vector control operations can be monitored by vector cytospecies identification, the frequency of polymorphic inversions which characterise the different vector populations, and the identification of accompanying non-vector cytospecies (e.g. S. plumbeum and cytotype Kasyabone occur exclusively in the two foci, and hence their re-appearance in Tukuyu could have only one outside source). The morphology of the scutal pattern of neonate males may act as a quick test for vector species identification where chromosome squashes are unavailable.

[A new blackfly species Montisimulium birzhankolum Yankovsky, Isakaev et Khasanova, sp. n. (Diptera: Simuliidae) from northeastern Kazakhstan].

A new species of blackflies, Montisimulium birzhankolum Yankovsky, Isakaev et Khasanova, sp. n., is described from male, female, and pupa specimens collected in Pavlodar Province of Northeastern Kazakhstan. The new species differs from all other species of the genus Montisimulium by morphology of pupal gills.

Occurrence of filamentous fungi in Simulium goeldii Cerqueira & Nunes de Mello (diptera: simuliidae) larvae in central Amazonia, Brazil / Ocorrência de fungos filamentosos associados a larvas de Simulium goeldii Cerqueira & Nunes de Mello da Amazônia Central, Brasil

The family Simuliidae is the host of simbiontes fungi that inhabit the digestive tracts of arthropods. This paper reports the presence of fungi in Simulium goeldii Cerqueira & Nunes de Mello larvae in Amazonia. We observed that the larvae are a good component of aquatic systems to isolate filamentous fungi.

A família Simuliidae é hospedeira de fungos simbiontes que habitam o trato digestivo de artrópodos. Este estudo reporta a presença de fungos em larvas de Simulium goeldii Cerqueira & Nunes de Mello da Amazônia. Foi observado que as larvas são bons componentes do sistema aquático para isolar fungos filamentosos.

[Comparative study on polytene chromosomes of two isolates of Simulium quinquestriatus].

The salivary glands were exposed and isolated from the larvae of Simulium quinquestriatus and stained in carbol fuchsin, squashed between slide and coverslide. Slides were examined and photographed under microscope to measure the polytene chromosomes. Systematic analysis was made. Results indicated that the number of the polytene chromosomes of both isolates is three. The main characteristic chromosomal structures are homologized. Only the banding types of II L are different.

Susceptibility of Simulium damnosum complex larvae to temephos in the Tukuyu onchocerciasis focus; southwest Tanzania

Tukuyu onchocerciasis focus was earmarked for vector control using insecticide against larval stages.Susceptibility tests of mature larvae of Simulium damnosum s.l. vectors to temephos insecticide were carried out before and after two years of insecticide treatment of rivers within Tukuyu onchocerciasis focus, south-western Tanzania. The tests were done in 1999/2000 and 2004 using WHO standard methods. Mature larvae were exposed to 9 concentrations of temephos active ingredient, from the weakest 0.00975mg/litre to the strongest of 2.5mg/l. Each test concentration and control was run in duplicates of 25 larvae each, set for three hours in a cool temperature. After incubation, test solution was discarded and larval condition checked. Numbers of larvae in each category were recorded and used to determine mortality rate for each concentration as well as for the LC50 and LC95. A total of 1,666 larvae were tested, 942 during the pre- and 724 post-treatment. Results showed that both pre and post-treatment samples were susceptible, attaining 100% mortality at the diagnostic dose of 1.25mg/l, and LC50 between 0.129-0.34mg/l pre - and 0.144-0.211 mg/l (95% CI, P<0.05) post- treatment. These values fall within the standard diagnostic dose of ≤0.4mg/l for susceptible S. damnosum s.l populations. It was concluded that the endemic S. damnosum population was susceptible to temephos before and after two years of intermittent field application. Temephos was thus recommended for continued use in onchocerciasis vector control in the Tukuyu focus, to complement Community Directed Treatment with Ivermectin, but close monitoring of vector susceptibility should be done

Cytogenetic and PCR-based identification of S. damnosum "Nkusi J" as the anthropophilic blackfly in the Uluguru onchocerciasis focus in Tanzania.

A combined molecular and cytogenetic analysis was used to identify the local blackfly vectors of onchocerciasis in the Uluguru Mts. focus, Morogoro region, central Tanzania. Cytotaxonomic identification revealed the occurrence of three cytospecies of the Simulium damnosum complex, along altitudinal gradients. The cytoform "Nkusi" was found breeding at low to mid-altitudes (100-500 m), while S. kilibanum was found at mid- and high altitudes (300-1260 m), being sympatric with "Sebwe" only in the highlands. The analyses further revealed the cytoform "Nkusi" from the nearby Kilosa focus. Simulium kilibanum and "Nkusi" are potential vectors of onchocerciasis, while the "Sebwe" form is considered non-anthropophilic and therefore not a vector. By means of molecular typing of wild-caught females, "Nkusi" was incriminated as the man-biting fly at all catching sites, and consequently, is the assumed vector of onchocerciasis over the full altitude range. In the high altitude zones, however, S. neavei group species may act as secondary vectors at the edge of the forest reserve, if transmission actually occurs there at all. Our results also suggest that vector control could be feasible because of the vector species breeding in the foothills below 500 m in relatively accessible open country.

Deforestation and the spatio-temporal distribution of savannah and forest members of the Simulium damnosum complex in southern Ghana and south-western Togo.

Spatio-temporal data on cytotaxonomic identifications of larvae of different members of the Simulium damnosum complex collected from rivers in southern Ghana and south-western Togo from 1975 until 1997 were analysed. When the data were combined, the percentages of savannah blackflies (S. damnosum sensu stricto and S. sirbanum) in the samples were shown to have been progressively increasing since 1975. The increases were statistically significant (P < 0.001), but the rates of increase were not linear. Further analyses were conducted according to the collection seasons and locations of the samples, to account for possible biases such as savannah flies occurring further south in the dry season or a preponderance of later samples from northern rivers having more savannah flies. These analyses showed that the increasing trend was statistically significant (P < 0.0001) only during the periods April to June and October to December. The presence of adult savannah flies carrying infective larvae (L3) indistinguishable from those of Onchocerca volvulus in the study zone was confirmed by examinations of captured flies. The percentages of savannah flies amongst the human-biting populations and the percentages with L3s in the head were higher during dry seasons than wet seasons and the savannah species were found furthest south (5 degrees 25'N) in the dry season. Comparisons of satellite images taken in 1973 and 1990 over a study area in south-western Ghana encompassing stretches of the Tano and Bia rivers demonstrated that there have been substantial increases in urban and savannah areas, at the expense of forest. This was so not only for the whole images but also for subsamples of the images taken at 1, 2, 4, 8 and 16 km distant from sites alongside the River Tano. At every distance from the river, the percentages of pixels classified as urban or savannah have increased in 1990 compared with 1973, while those classified as degraded or dense forest have decreased. The possibility that the proportionate increases in savannah forms of the vectors of onchocerciasis, and hence in the likelihood of the transmission of savannah strains of the disease in formerly forested areas, were related to the decreases in forest cover is discussed.

[New observation in France of a nuisance due to Simulium (Boophthora) erythrocephalum (De Geer, 1776) (Diptera, Simuliidae)]. / Nouvelle observation en France d'une nuisance due à simulium (boophthora) erythrocephalum (de geer, 1776) (diptera, simuliidae).

Some nuisance due to Simuliidae appeared near the French border with Spain (Pyrénées-Orientales) during the summer 1998. Larvae and pupae were collected in the lower parts of the rivers Têt, Tech and Agly. The identification demonstrated the occurrence of Simulium erythrocephalum. If the nuisance would become durable, a control campaign should be initiated.

Onchocerciasis in the Amazonian focus of southern Venezuela: altitude and blackfly species composition as predictors of endemicity to select communities for ivermectin control programmes.

In preparation for an ivermectin distribution programme, the prevalence and intensity of infection due to Onchocerca volvulus as well as the species composition and abundance of Simulium vectors were investigated in 22 Yanomami communities situated along 2 altitudinal transects in the southern Venezuelan onchocerciasis focus. These transects corresponded to the Ocamo-Putaco and Orinoco-Orinoquito river systems, covering a range of elevation between 50 m and 740 m above sea level (asl). A total of 831 people underwent parasitological examination in this survey and an additional 196 patients from a previous study, at an altitude of 950 m, were included in the analysis. A total of 92,659 man-biting blackflies were collected and identified to morphospecies. S. oyapockense s.l. was the predominant simuliid up to 150 m asl, whereas S. guianense s.l. and S. incrustatum s.l. prevailed above 150 m. Communities located below 150 m were found to range from hypo- to mesoendemic; all villages above 150 m proved to be hyperendemic (> 60% microfilarial prevalence) and mass ivermectin treatment should be implemented. Age above 10-14 years, altitude of the village and biting rate of S. guianense s.l. up to 200 m asl were found to be statistically significant independent predictors of infection by multivariate logistic regression using a spline model. There were no differences in infection status according to sex. Above 200 m, microfilarial rate and density remained approximately constant, prevalence averaging 79% regardless of blackfly abundance. For the implementation of ivermectin-based onchocerciasis control programmes in the Amazonian focus, altitude and species composition of the blackfly population might be adopted as useful indicators aiding selection of the most affected communities. However, below 200 m additional parasitological indicators may also be necessary. As a direct result of this study, regular mass-ivermectin delivery to meso- and hyperendemic communities is now in progress.

Cytotaxonomic identifications of the Simulium damnosum complex (Diptera:Simuliidae) from Nigeria.

Cytotaxonomic analysis of Simulium damnosum s.l. larvae collected from 23 sites across 4 bioclimatic zones in Nigeria revealed the presence of 5 cytospecies (S. damnosum s.str., S. sirbanum, S. squamosum, S. yahense and S. soubrense (including the Beffa form). The biogeographical distribution of the sibling species was mostly similar to that observed further west in the OCP area, although geographic cytotaxonomic variation was recorded in S. squamosum, S. damnosum s.str. and S. sirbanum. Some aspects of the chemical and physical environment of the breeding habitats were investigated.

Insects feeding on desert bighorn sheep, domestic rabbits, and Japanese quail in the Santa Rosa mountains of southern California.

Desert bighorn sheep (Ovis canadensis cremnobates), a domestic rabbit (Oryctolagus cuniculus), and Japanese quail (Coturnix japonica) were used as bait animals to collect blood-feeding flies in an area of active blue-tongue and epizootic hemorrhagic disease virus transmission. Precipitin tests were used to confirm the blood source where feasible. Eight species of Culicoides, members of the Leptoconops kerteszi group, Simulium spp., Anopheles franciscanus, and Stomoxys calcitrans were collected from the bighorn sheep. Feeding on the bighorn sheep by Culicoides brookmani (n = 25), C. variipennis (n = 6), C. cacticola (n = 1), and Simulium spp. (n = 3) was confirmed by precipitin testing. Primary species attacking the rabbit were C. brookmani, C. variipennis, and the L. kerteszi group. The quail were attacked primarily by members of the C. copiosus group and the L. kerteszi group.