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Background: Leucocytozoonosis, a parasitic disease of birds, is caused by haemosporidian protozoan parasites of the genus Leucocytozoon, which infect diverse avian species, including poultry. These parasites are transmitted by several black fly species, but knowledge of the factors determining the diversity and prevalence in these vectors, which is crucial for fully understanding disease epidemiology, is largely unexplored. In this study, we investigated factors associated with the prevalence and diversity of Leucocytozoon species in black flies from Thailand. Methods: Adults of two black fly taxa (Simulium asakoae Takaoka and Davies complex and S. khelangense Takaoka, Srisuka and Saeung) were collected using sweep nets at nine locations in northern and northeastern regions of Thailand. Specimens were identified morphologically and the results corroborated by DNA barcoding. Molecular methods using specific primers for amplification of the mitochondrial cytochrome b (cyt b) gene of Leucocytozoon were used to detect the parasite in black flies. Species and lineages of Leucocytozoon were determined using the MalAvi database of malaria parasites and related haemosporidians in avian hosts. Regression analysis was used to examine relationships between Leucocytozoon diversity and prevalence, black fly abundance and habitat characteristics. Results: A total of 11,718 adult black flies were collected, of which 4367 were members of the S. asakoae complex and 7351 were S. khelangense. For molecular detection of Leucocytozoon, we randomly selected 300 individual female black flies of the S. asakoae complex and 850 females of S. khelangense pooled into groups of five individuals (= 170 pools). A total of 34 of the 300 specimens of the S. asakoae complex and 118 of the 170 pools of S. khelangense were positive for Leucocytozoon. Fifty-four lineages (haplotypes) were identified, all of which belonged to those reported in domestic chickens, Gallus gallus, with one exception that was identified in S. khelangense and found to be closely related to the Leucocytozoon lineages reported in owls; this is the first record of the latter lineage in Asian black flies. Among these haplotypes, nine and 45 were exclusively found in the S. asakoae complex and S. khelangense, respectively. No lineage was shared between these black fly taxa. Analysis of similarity (ANOSIM) revealed significant Leucocytozoon lineage composition between the two black flies. Phylogenetic analysis found that Leucocytozoon lineages in the S. asakoae complex and S. khelangense are largely isolated, agreeing with the ANOSIM result. The overall prevalence of Leucocytozoon in the S. asakoae complex was 11.3% and ranged from 9% to 13% in each collection. Leucocytozoon prevalence in S. khelangense was 21%, varying from 13% to 37% in each collection. The Shannon H′ index indicated greater Leucocytozoon diversity in S. khelangense (H′ = 3.044) than in the S. asakoae complex (H′ = 1.920). Regression analysis revealed that Leucocytozoon diversity was positively related to black fly abundance and negatively related to maximum air temperature. Conclusions: The results of this study show that the prevalence and diversity of Leucocytozoon lineages in the S. asakoae complex and S. khelangense from Thailand were associated with the abundance of these black flies and with air temperature. The Leucocytozoon lineages identified also showed some degree of black fly taxon specificity, possibly related to different abundance peaks of these vectors. The environmental conditions that favor the development of black flies are possibly a driver of Leucocytozoon prevalence, diversity and vector–parasite co-evolution. [ABSTRACT FROM AUTHOR]

Cryptic species are black boxes of taxonomy and need to be addressed with an integrative taxonomic approach. Simulium (Diptera: Simuliidae) may contain a substantial amount of cryptic species diversity due to its large cross-continental distribution and habitat-based canalization in taxonomic characters. Except for Simulium sergenti , the following six species Simulium equinum , Simulium paraequinum , Simulium pseudequinum , Simulium turgaicum , Simulium balcanicum , and Simulium lineatum are the most widely distributed species of the subgenus Wilhelmia in the Palearctic region. However, the conspecific diversity and evolutionary history of these species are not yet well understood. In this study, therefore, we used mitochondrial COI and nuclear ITS1-2 sequences to perform species delimitation tests, and demographic and phylogeographic analyses to understand candidate species and evolutionary history of the seven species. While our results did not support the species status of S. balcanicum , S. turgaicum , and S. lineatum , it did suggest several candidate species within S. equinum and S. pseudequinum. Molecular clock analysis revealed that significant branching events occurred in the Pliocene, and demographic fluctuations in the populations occurred intensely during the Pleistocene. Overall, the results indicated that Anatolia has served as a significant refugium for ancestral haplotypes, and it is an important dispersal corridor between the eastern and western Palearctic for Wilhelmia species. [ABSTRACT FROM AUTHOR]

Abstract Background Leucocytozoonosis, a parasitic disease of birds, is caused by haemosporidian protozoan parasites of the genus Leucocytozoon, which infect diverse avian species, including poultry. These parasites are transmitted by several black fly species, but knowledge of the factors determining the diversity and prevalence in these vectors, which is crucial for fully understanding disease epidemiology, is largely unexplored. In this study, we investigated factors associated with the prevalence and diversity of Leucocytozoon species in black flies from Thailand. Methods Adults of two black fly taxa (Simulium asakoae Takaoka and Davies complex and S. khelangense Takaoka, Srisuka and Saeung) were collected using sweep nets at nine locations in northern and northeastern regions of Thailand. Specimens were identified morphologically and the results corroborated by DNA barcoding. Molecular methods using specific primers for amplification of the mitochondrial cytochrome b (cyt b) gene of Leucocytozoon were used to detect the parasite in black flies. Species and lineages of Leucocytozoon were determined using the MalAvi database of malaria parasites and related haemosporidians in avian hosts. Regression analysis was used to examine relationships between Leucocytozoon diversity and prevalence, black fly abundance and habitat characteristics. Results A total of 11,718 adult black flies were collected, of which 4367 were members of the S. asakoae complex and 7351 were S. khelangense. For molecular detection of Leucocytozoon, we randomly selected 300 individual female black flies of the S. asakoae complex and 850 females of S. khelangense pooled into groups of five individuals (= 170 pools). A total of 34 of the 300 specimens of the S. asakoae complex and 118 of the 170 pools of S. khelangense were positive for Leucocytozoon. Fifty-four lineages (haplotypes) were identified, all of which belonged to those reported in domestic chickens, Gallus gallus, with one exception that was identified in S. khelangense and found to be closely related to the Leucocytozoon lineages reported in owls; this is the first record of the latter lineage in Asian black flies. Among these haplotypes, nine and 45 were exclusively found in the S. asakoae complex and S. khelangense, respectively. No lineage was shared between these black fly taxa. Analysis of similarity (ANOSIM) revealed significant Leucocytozoon lineage composition between the two black flies. Phylogenetic analysis found that Leucocytozoon lineages in the S. asakoae complex and S. khelangense are largely isolated, agreeing with the ANOSIM result. The overall prevalence of Leucocytozoon in the S. asakoae complex was 11.3% and ranged from 9% to 13% in each collection. Leucocytozoon prevalence in S. khelangense was 21%, varying from 13% to 37% in each collection. The Shannon H′ index indicated greater Leucocytozoon diversity in S. khelangense (H′ = 3.044) than in the S. asakoae complex (H′ = 1.920). Regression analysis revealed that Leucocytozoon diversity was positively related to black fly abundance and negatively related to maximum air temperature. Conclusions The results of this study show that the prevalence and diversity of Leucocytozoon lineages in the S. asakoae complex and S. khelangense from Thailand were associated with the abundance of these black flies and with air temperature. The Leucocytozoon lineages identified also showed some degree of black fly taxon specificity, possibly related to different abundance peaks of these vectors. The environmental conditions that favor the development of black flies are possibly a driver of Leucocytozoon prevalence, diversity and vector–parasite co-evolution. Graphical Abstract

Vesicular stomatitis (VS) is a viral disease that affects horses, cattle, and swine that is transmitted by direct contact and hematophagous insects. In 2023, a multi-state outbreak of vesicular stomatitis New Jersey virus (VSNJV) occurred in California, Nevada, and Texas, infecting horses, cattle, and rhinoceros. To identify possible insect vectors, we conducted insect surveillance at various locations in San Diego County, CA, including at a wildlife park. CO2 baited traps set from mid-May to mid-August 2023 collected 2357 Culicoides biting midges and 1215 Simulium black flies, which are insect genera implicated in VSNJV transmission. Insects were pooled by species, location, and date, then tested for viral RNA. Nine RNA-positive pools of Culicoides spp. and sixteen RNA-positive pools of Simulium spp were detected. Infectious virus was detected by cytopathic effect in 96% of the RNA-positive pools. This is the first report of VSNJV in wild-caught C. bergi, C. freeborni, C. occidentalis, S. argus, S. hippovorum, and S. tescorum. The vector competency of these species for VSNJV has yet to be determined but warrants examination. Active vector surveillance and testing during disease outbreaks increases our understanding of the ecology and epidemiology of VS and informs vector control efforts. [ABSTRACT FROM AUTHOR]

Simple Summary: Blackflies are small blood-sucking flies that can carry and transmit the parasitic worm Onchocerca volvulus, the causative agent of human onchocerciasis, also known as "river blindness". As gravid blackfly females oviposit their eggs in the fast-moving water of rivers and streams, the geographic distributions of both the vectors and the parasite that they transmit are closely linked with river basins. How blackflies disperse from and return to their breeding sites, the spatial distribution of their movements, and the distances that they can travel are crucial factors influencing transmission. As many endemic countries strive for elimination, understanding these patterns is important for guiding the design of monitoring and surveillance efforts. Here, we summarize the literature on the short-range and long-range dispersal of members of the Simulium damnosum complex and other onchocerciasis vectors and how this may influence exposure to blackfly bites, highlight significant gaps in existing knowledge, and propose possible directions for future research. This is particularly important in view of current global onchocerciasis elimination programs. Blackfly members of the Simulium damnosum complex are major vectors of the parasite that causes onchocerciasis in Africa and Yemen, with other vector species involved in a few localized areas of Africa and in the Neotropics. Although the life cycle of these blackflies is linked to fast-flowing rivers, they can travel long distances (up to at least 500 km), calling into question how transmission zones are defined. Knowledge of the short- and long-range dispersal of these vectors could inform where control interventions and monitoring are necessary if targets for onchocerciasis elimination are to be met. Yet, research on blackfly dispersal has been limited and fragmented over the last 70 years. Here, we review the literature on the dispersal of onchocerciasis vectors, and we show the need for further research to establish how far larvae can travel downstream; the extent to which adults invade transmission zones; and whether adults migrate in a series of successive short movements or in single long-distance shifts, or use both methods. [ABSTRACT FROM AUTHOR]

Onchocerciasis, or river blindness, has historically been one of the most important causes of blindness worldwide, and a major cause of socio-economic disruption, particularly in sub-Saharan Africa. Its importance as a cause of morbidity and an impediment to economic development in some of the poorest countries in the world motivated the international community to implement several programs to control or eliminate this scourge. Initially, these involved reducing transmission of the causative agent Onchocerca volvulus through controlling the vector population. When ivermectin was found to be a very effective drug for treating onchocerciasis, the strategy shifted to mass drug administration (MDA) of endemic communities. In some countries, both vector control and ivermectin MDA have been used together. However, traditional vector control methods involve treating rivers in which the black fly vectors breed with insecticides, a process which is expensive, requires trained personnel to administer, and can be ecologically harmful. In this review, we discuss recent research into alternatives to riverine insecticide treatment, which are inexpensive, ecologically less harmful, and can be implemented by the affected communities themselves. These can dramatically reduce vector densities and, when combined with ivermectin MDA, can accelerate the time to elimination when compared to MDA alone. [ABSTRACT FROM AUTHOR]

Simple Summary: Black flies are small-sized (<6 mm) blood-sucking insects belonging to the family Simuliidae of the order Diptera. More than 2400 species have been recorded globally, and approximately 6% (145 species) are found in Thailand. Many black fly species are pests to humans and other animals. They also transmit pathogens such as viruses, protozoa and filarial nematodes to humans and other animals, including economically significant livestock. Therefore, knowledge of species the diversity and distribution of wild adults, as well as host blood sources, provides important information required to prevent problems related to black fly biting. In this study, we collected 7706 wild adult black flies over a seven-year period (2017–2023) from diverse natural habitats in Thailand. In total, 16 black fly taxa were recorded; one of them, Simulium yvonneae Takaoka and Low, is a new record for the country. The majority of the specimens were Simulium asakoae Takaoka and Davies complex, contributing 74% of the total number of specimens collected. This species predominantly occurs in forest and urban habitats. The second most abundant species, S. chumpornense Takaoka and Kuvangkadilok (16% of the total specimens collected) was predominant in domestic animal shelters. Host blood meal identification using molecular approaches revealed four vertebrate host species: humans, chickens, turkeys and water buffalo. Understanding the factors associated with the species diversity and distribution of insect vectors is critically important for disease epidemiology. Black flies (Diptera: Simuliidae) are significant hematophagous insects, as many species are pests and vectors that transmit pathogens to humans and other animals. Ecological factors associated with black fly species distribution have been extensively examined for the immature stages but are far less well explored for the adult stage. In this study, we collected a total of 7706 adult black fly specimens from various locations in forests, villages and animal shelters in Thailand. The integration of morphology and DNA barcoding revealed 16 black fly taxa, including Simulium yvonneae, a species first found in Vietnam, which is a new record for Thailand. The most abundant species was the Simulium asakoae complex (n = 5739, 74%), followed by S. chumpornense Takaoka and Kuvangkadilok (n = 1232, 16%). The Simulium asakoae complex was dominant in forest (3786 of 4456; 85%) and village (1774 of 2077; 85%) habitats, while S. chumpornense predominated (857 of 1175; 73%) in animal shelter areas. The Simulium asakoae complex and S. nigrogilvum Summers, which are significant pests and vectors in Thailand, occurred at a wide range of elevations, although the latter species was found mainly in high (>1000 m) mountain areas. Simulium chumpornense, S. nodosum Puri and the S. siamense Takaoka and Suzuki complex occurred predominately in low (<800 m)-elevation areas. Simulium furvum Takaoka and Srisuka; S. phurueaense Tangkawanit, Wongpakam and Pramual; and S. nr. phurueaense were only found in high (>1000 m) mountain areas. A host blood meal analysis revealed that the S. asakoae; S. chamlongi Takaoka and Suzuki; S. nigrogilvum; S. chumpornense; and the S. striatum species group were biting humans. This is the first report of the latter two species biting humans. We also found that S. chumpornense was biting turkeys, and S. chamlongi was biting chickens, which are new host blood sources recorded for these species. In addition, we found that the S. feuerborni Edwards complex was biting water buffalo, which is the first report on the biting habits of this species. [ABSTRACT FROM AUTHOR]

Vesicular stomatitis (VS) is a viral disease that affects horses, cattle, and swine that is transmitted by direct contact and hematophagous insects. In 2023, a multi-state outbreak of vesicular stomatitis New Jersey virus (VSNJV) occurred in California, Nevada, and Texas, infecting horses, cattle, and rhinoceros. To identify possible insect vectors, we conducted insect surveillance at various locations in San Diego County, CA, including at a wildlife park. CO2 baited traps set from mid-May to mid-August 2023 collected 2357 Culicoides biting midges and 1215 Simulium black flies, which are insect genera implicated in VSNJV transmission. Insects were pooled by species, location, and date, then tested for viral RNA. Nine RNA-positive pools of Culicoides spp. and sixteen RNA-positive pools of Simulium spp were detected. Infectious virus was detected by cytopathic effect in 96% of the RNA-positive pools. This is the first report of VSNJV in wild-caught C. bergi, C. freeborni, C. occidentalis, S. argus, S. hippovorum, and S. tescorum. The vector competency of these species for VSNJV has yet to be determined but warrants examination. Active vector surveillance and testing during disease outbreaks increases our understanding of the ecology and epidemiology of VS and informs vector control efforts.

Blackfly members of the Simulium damnosum complex are major vectors of the parasite that causes onchocerciasis in Africa and Yemen, with other vector species involved in a few localized areas of Africa and in the Neotropics. Although the life cycle of these blackflies is linked to fast-flowing rivers, they can travel long distances (up to at least 500 km), calling into question how transmission zones are defined. Knowledge of the short- and long-range dispersal of these vectors could inform where control interventions and monitoring are necessary if targets for onchocerciasis elimination are to be met. Yet, research on blackfly dispersal has been limited and fragmented over the last 70 years. Here, we review the literature on the dispersal of onchocerciasis vectors, and we show the need for further research to establish how far larvae can travel downstream; the extent to which adults invade transmission zones; and whether adults migrate in a series of successive short movements or in single long-distance shifts, or use both methods.

Abstract Background Prompt and precise identification of black flies (Simuliidae) is crucial, given their biting behaviour and significant impact on human and animal health. To address the challenges presented by morphology and chromosomes in black fly taxonomy, along with the limited availability of molecular data pertaining to the black fly fauna in Vietnam, this study employed DNA-based approaches. Specifically, we used mitochondrial and nuclear-encoded genes to distinguish nominal species of black flies in Vietnam. Methods In this study, 135 mitochondrial cytochrome c oxidase subunit I (COI) sequences were established for 45 species in the genus Simulium in Vietnam, encompassing three subgenera (Gomphostilbia, Nevermannia, and Simulium), with 64 paratypes of 27 species and 16 topotypes of six species. Of these COI sequences, 71, representing 27 species, are reported for the first time. Results Combined with GenBank sequences of specimens from Malaysia, Myanmar, Thailand, and Vietnam, a total of 234 DNA barcodes of 53 nominal species resulted in a 71% success rate for species identification. Species from the non-monophyletic Simulium asakoae, S. feuerborni, S. multistriatum, S. striatum, S. tuberosum, and S. variegatum species groups were associated with ambiguous or incorrect identifications. Pairwise distances, phylogenetics, and species delimitation analyses revealed a high level of cryptic diversity, with discovery of 15 cryptic taxa. The current study also revealed the limited utility of a fast-evolving nuclear gene, big zinc finger (BZF), in discriminating closely related, morphologically similar nominal species of the S. asakoae species group. Conclusion This study represents the first comprehensive molecular genetic analysis of the black fly fauna in Vietnam to our knowledge, providing a foundation for future research. DNA barcoding exhibits varying levels of differentiating efficiency across species groups but is valuable in the discovery of cryptic diversity. Graphical abstract

Abstract Background DNA barcoding is a valuable taxonomic tool for rapid and accurate species identification and cryptic species discovery in black flies. Indonesia has 143 nominal species of black flies, but information on their biological aspects, including vectorial capacity and biting habits, remains underreported, in part because of identification problems. The current study represents the first comprehensive DNA barcoding of Indonesian black flies using mitochondrial cytochrome c oxidase subunit I (COI) gene sequences. Methods Genomic DNA of Indonesian black fly samples were extracted and sequenced, producing 86 COI sequences in total. Two hundred four COI sequences, including 118 GenBank sequences, were analysed. Maximum likelihood (ML) and Bayesian inference (BI) trees were constructed and species delimitation analyses, including ASAP, GMYC and single PTP, were performed to determine whether the species of Indonesian black flies could be delineated. Intra- and interspecific genetic distances were also calculated and the efficacy of COI sequences for species identification was tested. Results The DNA barcodes successfully distinguished most morphologically distinct species (> 80% of sampled taxa). Nonetheless, high maximum intraspecific distances (3.32–13.94%) in 11 species suggested cryptic diversity. Notably, populations of the common taxa Simulium (Gomphostilbia) cheongi, S. (Gomphostilbia) sheilae, S. (Nevermannia) feuerborni and S. (Simulium) tani in the islands of Indonesia were genetically distinct from those on the Southeast Asian mainland (Malaysia and Thailand). Integrated morphological, cytogenetic and nuclear DNA studies are warranted to clarify the taxonomic status of these more complex taxa. Conclusions The findings showed that COI barcoding is a promising taxonomic tool for Indonesian black flies. The DNA barcodes will aid in correct identification and genetic study of Indonesian black flies, which will be helpful in the control and management of potential vector species. Graphical abstract

Background: Prompt and precise identification of black flies (Simuliidae) is crucial, given their biting behaviour and significant impact on human and animal health. To address the challenges presented by morphology and chromosomes in black fly taxonomy, along with the limited availability of molecular data pertaining to the black fly fauna in Vietnam, this study employed DNA-based approaches. Specifically, we used mitochondrial and nuclear-encoded genes to distinguish nominal species of black flies in Vietnam. Methods: In this study, 135 mitochondrial cytochrome c oxidase subunit I (COI) sequences were established for 45 species in the genus Simulium in Vietnam, encompassing three subgenera (Gomphostilbia, Nevermannia, and Simulium), with 64 paratypes of 27 species and 16 topotypes of six species. Of these COI sequences, 71, representing 27 species, are reported for the first time. Results: Combined with GenBank sequences of specimens from Malaysia, Myanmar, Thailand, and Vietnam, a total of 234 DNA barcodes of 53 nominal species resulted in a 71% success rate for species identification. Species from the non-monophyletic Simulium asakoae, S. feuerborni, S. multistriatum, S. striatum, S. tuberosum, and S. variegatum species groups were associated with ambiguous or incorrect identifications. Pairwise distances, phylogenetics, and species delimitation analyses revealed a high level of cryptic diversity, with discovery of 15 cryptic taxa. The current study also revealed the limited utility of a fast-evolving nuclear gene, big zinc finger (BZF), in discriminating closely related, morphologically similar nominal species of the S. asakoae species group. Conclusion: This study represents the first comprehensive molecular genetic analysis of the black fly fauna in Vietnam to our knowledge, providing a foundation for future research. DNA barcoding exhibits varying levels of differentiating efficiency across species groups but is valuable in the discovery of cryptic diversity. [ABSTRACT FROM AUTHOR]

Background: DNA barcoding is a valuable taxonomic tool for rapid and accurate species identification and cryptic species discovery in black flies. Indonesia has 143 nominal species of black flies, but information on their biological aspects, including vectorial capacity and biting habits, remains underreported, in part because of identification problems. The current study represents the first comprehensive DNA barcoding of Indonesian black flies using mitochondrial cytochrome c oxidase subunit I (COI) gene sequences. Methods: Genomic DNA of Indonesian black fly samples were extracted and sequenced, producing 86 COI sequences in total. Two hundred four COI sequences, including 118 GenBank sequences, were analysed. Maximum likelihood (ML) and Bayesian inference (BI) trees were constructed and species delimitation analyses, including ASAP, GMYC and single PTP, were performed to determine whether the species of Indonesian black flies could be delineated. Intra- and interspecific genetic distances were also calculated and the efficacy of COI sequences for species identification was tested. Results: The DNA barcodes successfully distinguished most morphologically distinct species (> 80% of sampled taxa). Nonetheless, high maximum intraspecific distances (3.32–13.94%) in 11 species suggested cryptic diversity. Notably, populations of the common taxa Simulium (Gomphostilbia) cheongi, S. (Gomphostilbia) sheilae, S. (Nevermannia) feuerborni and S. (Simulium) tani in the islands of Indonesia were genetically distinct from those on the Southeast Asian mainland (Malaysia and Thailand). Integrated morphological, cytogenetic and nuclear DNA studies are warranted to clarify the taxonomic status of these more complex taxa. Conclusions: The findings showed that COI barcoding is a promising taxonomic tool for Indonesian black flies. The DNA barcodes will aid in correct identification and genetic study of Indonesian black flies, which will be helpful in the control and management of potential vector species. [ABSTRACT FROM AUTHOR]

Abstract Despite the ongoing onchocerciasis control program that has been in place in Mahenge for more than two decades using the Community Directed Treatment with Ivermectin (CDTI) strategy, the persistent transmission of onchocerciasis has been observed, proving that CDTI alone is unable to interrupt the transmission. This letter aims to highlight how drone-based remote sensing technology can be utilized for Simulium surveillance and control in Mahenge and suggest measures that can be employed to initiate the vector control intervention using the proposed technology in Mahenge. The drone-based technology in Mahenge could assist in the identification of Simulium breeding sites even in inaccessible parts of rivers and streams, mapping the microenvironmental composition, and suggesting potential control measures, including whether to apply larviciding using drones or where the ground control effort of slashing and clearing should be prioritized. Therefore, now is an opportune time to combine CDTI and Simulium control interventions to achieve sustainable onchocerciasis control in Mahenge.

The present study provides faunal data for Turkish Black flies (Simuliidae, Diptera) from the Central and Western Mediterranean Region in Türkiye. Among the specimens collected from 221 different running water sites, 17 species in 3 genera and 5 subgenera were identified. Two species, Simulium (Nevermannia) ibleum (Rivosecchi 1966) and Simulium (Nevermannia) brevidens (Rubtsov 1956), were recorded for the first time from Türkiye, and 5 additional species were reported from the study area for the first time. The morphological identifications were tested by phylogenetic analyzes using mitochondrial cytochrome oxidase I (COI) barcode sequences. The COI analysis results overlapped with the morphotaxonomic identification results for eight of the 15 species. The first genetic data of 4 species (for World) and 5 species (from Türkiye) were stored in GenBank (NCBI). [ABSTRACT FROM AUTHOR]

In the present study, the genetic diversity of Onchocerca (O.) species was investigated by amplifying a fragment of the 16S rRNA gene from the parasite obtained in some endemic areas in Taraba State, Nigeria. Three local government areas were selected: two onchocerciasisendemic and one non-onchocerciasis-endemic regions. A total of 211 skin snips using a sterile sclera punch were obtained from consenting participants, males and females residing within the areas for at least ten years or since birth, by convenience sampling methods. The emerged microfilariae were examined microscopically. Nine microfilaria-positive skin snips were identified and preserved in RNALater®. DNA was extracted from recovered microfilariae and residual skin snip specimens and was tested by standard Polymerase Chain Reaction (PCR) using primers targeting the 16S gene. Six PCR-positive samples were sequenced and analyzed. Two sequences varied with those from other regions, suggesting a likely diversity of O. volvulus populations in the study area. A novel finding of O. ochengi, the pathogenic cattle parasite, was identified in some samples, suggesting a potential zoonotic species in humans. Further investigation on the extent of emerging zoonotic onchocerciasis by O. ochengi in the light of cattle, Simulium vectors (blackflies), and environmental and human overlap in the study area is required. [ABSTRACT FROM AUTHOR]

Onchocerciasis, or river blindness, has historically been one of the most important causes of blindness worldwide, and a major cause of socio-economic disruption, particularly in sub-Saharan Africa. Its importance as a cause of morbidity and an impediment to economic development in some of the poorest countries in the world motivated the international community to implement several programs to control or eliminate this scourge. Initially, these involved reducing transmission of the causative agent Onchocerca volvulus through controlling the vector population. When ivermectin was found to be a very effective drug for treating onchocerciasis, the strategy shifted to mass drug administration (MDA) of endemic communities. In some countries, both vector control and ivermectin MDA have been used together. However, traditional vector control methods involve treating rivers in which the black fly vectors breed with insecticides, a process which is expensive, requires trained personnel to administer, and can be ecologically harmful. In this review, we discuss recent research into alternatives to riverine insecticide treatment, which are inexpensive, ecologically less harmful, and can be implemented by the affected communities themselves. These can dramatically reduce vector densities and, when combined with ivermectin MDA, can accelerate the time to elimination when compared to MDA alone.

Understanding the factors associated with the species diversity and distribution of insect vectors is critically important for disease epidemiology. Black flies (Diptera: Simuliidae) are significant hematophagous insects, as many species are pests and vectors that transmit pathogens to humans and other animals. Ecological factors associated with black fly species distribution have been extensively examined for the immature stages but are far less well explored for the adult stage. In this study, we collected a total of 7706 adult black fly specimens from various locations in forests, villages and animal shelters in Thailand. The integration of morphology and DNA barcoding revealed 16 black fly taxa, including Simulium yvonneae, a species first found in Vietnam, which is a new record for Thailand. The most abundant species was the Simulium asakoae complex (n = 5739, 74%), followed by S. chumpornense Takaoka and Kuvangkadilok (n = 1232, 16%). The Simulium asakoae complex was dominant in forest (3786 of 4456; 85%) and village (1774 of 2077; 85%) habitats, while S. chumpornense predominated (857 of 1175; 73%) in animal shelter areas. The Simulium asakoae complex and S. nigrogilvum Summers, which are significant pests and vectors in Thailand, occurred at a wide range of elevations, although the latter species was found mainly in high (>1000 m) mountain areas. Simulium chumpornense, S. nodosum Puri and the S. siamense Takaoka and Suzuki complex occurred predominately in low (Simulium furvum Takaoka and Srisuka; S. phurueaense Tangkawanit, Wongpakam and Pramual; and S. nr. phurueaense were only found in high (>1000 m) mountain areas. A host blood meal analysis revealed that the S. asakoae; S. chamlongi Takaoka and Suzuki; S. nigrogilvum; S. chumpornense; and the S. striatum species group were biting humans. This is the first report of the latter two species biting humans. We also found that S. chumpornense was biting turkeys, and S. chamlongi was biting chickens, which are new host blood sources recorded for these species. In addition, we found that the S. feuerborni Edwards complex was biting water buffalo, which is the first report on the biting habits of this species.

Despite the rich biodiversity potential of Anatolia, the blackfly fauna of Türkiye has not been fully explored. In the present study, a sampling study for blackflies were performed in Western Black Sea Region in spring seasons from 2016 to 2018 and 15 blackfly species from 73 different lotic habitats have been reported. Simulium (Nevermannia) carthusiense Grenier amp; Dorier, 1959 is new for Turkish fauna. Ten species have been recorded from the region for the first time. Distributional remarks in Türkiye and the world are given along with brief taxonomic evaluations for each species.

Despite the ongoing onchocerciasis control program that has been in place in Mahenge for more than two decades using the Community Directed Treatment with Ivermectin (CDTI) strategy, the persistent transmission of onchocerciasis has been observed, proving that CDTI alone is unable to interrupt the transmission. This letter aims to highlight how drone-based remote sensing technology can be utilized for Simulium surveillance and control in Mahenge and suggest measures that can be employed to initiate the vector control intervention using the proposed technology in Mahenge. The drone-based technology in Mahenge could assist in the identification of Simulium breeding sites even in inaccessible parts of rivers and streams, mapping the microenvironmental composition, and suggesting potential control measures, including whether to apply larviciding using drones or where the ground control effort of slashing and clearing should be prioritized. Therefore, now is an opportune time to combine CDTI and Simulium control interventions to achieve sustainable onchocerciasis control in Mahenge. [ABSTRACT FROM AUTHOR]

• First survey on wild adult black flies in Malaysia using malaise trap. • 14.7 % of black flies species in Malaysia were caught including a few unknown species. • Adult female of Simulium tanahrataense was discovered for the first time. • Adult S. pahangense was caught for first time after 20 years. Most studies on black flies focus on the taxonomy and ecology of their aquatic stages. Despite posing a public health threat, the adults remain poorly studied in many countries, including Malaysia. The present study represents the first investigation of the distribution of wild-caught black flies from various ecological landscapes and climatic conditions in Malaysia. CO 2 -baited Malaise traps were set randomly at 41 sampling sites across Peninsular Malaysia from 2020 to 2023. In total, 532 black flies belonging to 14 species of four subgenera were captured. To ensure taxonomic rigor, specimens were identified to species morphologically and molecularly. The subgenus Gomphostilbia was the most abundant (71.43 %), followed by Simulium (14.28 %) and Davieselleum and Nevermannia each representing 7.14 % of the total captures. These species represented 14.74 % of the total species recorded from Malaysia. The most frequently collected species were Simulium roslihashimi (24.39 %), followed by S. aureohirtum, S. vanluni , and S. (Gomphostilbia) sp. 1 with 7.32 % each. The highest relative abundance was found for S. vanluni (86.09 %) and S. roslihashimi (7.14 %). Most species were found at elevation below 300 m (78.57 %); fewer were at elevation higher than 1,000 m (21.43 %). Two principal components accounted for 85.3 % of the total intersite variance. Simulium roslihashimi was found at almost every site, with a maximum relative humidity of 90 %. Simulium aureohirtum and S. vanluni were found at sites with relative humidity up to 73 %, but S. aureohirtum was found at higher temperatures (31 °C) compared with S. roslihashimi (28 °C) and S. vanluni (29 °C). The present study establishes the groundwork for further studies of wild adults in Malaysia and identifies the need to use more traps over the range of seasons and environmental conditions, particularly near breeding sites. [ABSTRACT FROM AUTHOR]

• A recent blood survey supports historic studies proposing simuliids transmit Hep B. • Simuliid transmission can explain a strong Hep B+and M. ozzardi + correlation. • Sexual behavior and/or injection drug use cannot explain Hep B outbreaks in the Amazon. Hepatitis B virus (HBV) outbreaks are typically associated with injection drug use and high-risk sexual behavior; however, some cannot be easily explained in these terms. The messy blood-feeding methods of simuliids, provoked Chanteau et al. to investigate the simuliid-facilitated Hepatitis-B transmission (SFHBVT) hypothesis in French Polynesia in the early 1990s. Souto et al. later proposed the hypothesis could explain a HBV outbreak in the Brazilian Amazon which they suggested was driven by the biting of the M. ozzardi vector Simulium oyapockense. A recent Amazon region blood bank survey has provided important further support for the SFHBVT hypothesis playing a role in Amazon region transmission, but the results of this study have hitherto not been discussed in a SFHBVT context. Mansonella ozzardi positive donations were significantly more likely to test positive in anti-HBc and anti-HBc plus HBsAg tests than were M. ozzardi negative donations, suggesting both exposure to the HBV and HBV infections are significantly more common in individuals infected with M. ozzardi. It is argued here that these Amazon region blood bank observations substantially increase the viability of the SFHBVT hypothesis and thus that the hypothesis should be considered more carefully when HBV disease control measures are formulated for the Brazilian Amazon region and indeed beyond. [ABSTRACT FROM AUTHOR]

Blackflies are dipterans that belong to the family Simuliidae, common inhabitants of lotic ecosystems. The present study reports the first record of Simulium (Chirostilbia) subpallidum Lutz for Buenos Aires, rising to eight registered species of blackflies in the province. This report represents, to date, the southernmost distribution detected for the species and subgenus in South America. [ABSTRACT FROM AUTHOR]

The territory of the Tyumen region is located in the West Siberian Lowland and is characterized by conditions favorable for the development of blood-sucking diptera insects. The fauna of the blood-sucking diptera insects of the Tyumen region is represented by 109 species and 4 subspecies: horseflies-35 species and 4 subspecies, mosquitoes-41 species, blackflies-16 species, biting midges-17 species. In the subzone of the southern taiga, Hybomitra ciureai, H. bimaculata, H. lundbecki, H. muehlfeldi, Haematopota pluvialis, Aedes cantans, A. punctor, Simulium maculatum, Culicoides punctatus dominate; in the subzone of aspenbirch forests-Tabanus bromius, Hybomitra ciureai, H. bimaculata, H. lundbecki, Atylotus fulvus, A. rusticus, Haematopota subcylindrica, H. pluvialis, Aedes cinereus, A. punctor, A. cantans, Simulium pusillum, Culicoides punctatus; in the forest-steppe zone-Tabanus bovinus, T. bromius, Hybomitra ciureai, H. bimaculata, H. lundbecki, Haematopota pluvialis, H. subcylindrica, Coquillettidia richiardii, Aedes caspius, A. albescens, A. cantans, Simulium maculatum, Culicoides punctatus. The total summer period of insects of this group ranges from 140 days in the subzone of the southern taiga to 170 days in the forest-steppe zone. Depending on the meteorological conditions of the spring-summer season, the start and end dates of summer may shift by 1-2 decades. The activity of horseflies and blackflies is observed during the daytime, and mosquitoes and biting midges are twilight insects and attack mainly in the morning and evening hours. The main abiotic factors determining the nature of the diurnal rhythm of the vital activity of diptera insects in the conditions of the Tyumen region are air temperature and illumination. [ABSTRACT FROM AUTHOR]

Background More than 40 million people live in onchocerciasis-endemic areas in Nigeria. For at least 19 y, mass drug administration (MDA) with ivermectin was implemented with at least 65% total population coverage in Kaduna, Kebbi and Zamfara states. Impact surveys done using skin biopsies yielded no infections. Serological and entomological assessments were undertaken to determine if onchocerciasis transmission had been interrupted and MDA could be stopped. Methods The presence of onchocerciasis-specific immunoglobulin G4 antibody was measured by enzyme=linked immunosorbent assay conducted on dried blood spots collected from 5- to 9-year-old children resident in each state. O-150 polymerase chain reaction testing of Simulium damnosum s.l. heads for Onchocerca volvulus DNA was done on black flies collected by human landing capture and Esperanza window traps. Results A total of 9078 children were surveyed across the three states. A total of 6139 vectors were collected from Kaduna state, 129 from Kebbi state and 2 from Zamfara state; all were negative. Kebbi and Zamfara states did thousands of hours of black fly catching and intensive river prospecting. The resulting low fly catch was due to a low fly population incapable of sustaining transmission. Conclusion Onchocerciasis transmission has been interrupted and the three states meet World Health Organization thresholds: seropositivity in children <0.1% and <1/2000 infective black flies with 95% confidence. The 2.2 million people in Kaduna state and 4 million in Kebbi and Zamfara states no longer need ivermectin for onchocerciasis. [ABSTRACT FROM AUTHOR]

Despite the ethical issues concerning the continued use of Human Landing Catches (HLC) to monitor the Simulium damnosum complex for epidemiological monitoring of onchocericasis, few attempts to develop alternatives have been reported. In studies on a wild population of S. damnosum in Burkina Faso, we tested visual targets (different sizes and shapes) and olfactory stimuli (CO2, and POCA and BG‐lure® odour blends) for their ability to attract and collect host seeking blackflies. At each trap, blackflies were caught with appropriately sized electrocuting grids and results from Latin square design tests were compared. Throughout, HLCs captured more blackflies than the targets. Of the traps tested, small targets (0.0625 and 0.5 m2) were the most efficient visual lure in terms of the number of S. damnosum captured per unit area 1.7–5× more than larger targets. Overall, results suggested that sticky black targets of horizontal rectangular shape (0.125–0.5 m2) and baited with a POCA and/or CO2 mixture could provide a cheap practical field alternative to HLC for onchocerciasis xenomonitoring, subject to confirmation that the design has no inherent bias for certain members of the S. damnosum species complex. [ABSTRACT FROM AUTHOR]

Despite the rich biodiversity potential of Anatolia, the blackfly fauna of Türkiye has not been fully explored. In the present study, a sampling study for blackflies were performed in Western Black Sea Region in spring seasons from 2016 to 2018 and 15 blackfly species from 73 different lotic habitats have been reported. Simulium (Nevermannia) carthusiense Grenier & Dorier, 1959 is new for Turkish fauna. Ten species have been recorded from the region for the first time. Distributional remarks in Türkiye and the world are given along with brief taxonomic evaluations for each species. [ABSTRACT FROM AUTHOR]

Mass drug administration (MDA) of ivermectin is currently the main strategy to achieve elimination of transmission (EoT) of onchocerciasis. Modelling suggests that EoT may not be reached in all endemic foci using annual MDA alone. Onchocerciasis and loiasis are coendemic in forest areas of Central Africa where ivermectin treatment can lead to severe adverse events in individuals with heavy loiasis load, rendering MDA inappropriate. Vector control has been proposed as a complementary intervention strategy. Here, we discuss (i) achievements and pitfalls of previous interventions; (ii) epidemiological impact, feasibility, and combination with MDA to accelerate and/or protect EoT; (iii) role of modelling; (iv) opportunities for innovative methods of vector monitoring and control; and (v) strengthening entomological capacity in endemic countries. Modelling studies have suggested that elimination of transmission (EoT) of onchocerciasis may not be achieved by relying solely on mass drug administration (MDA) of ivermectin, particularly in hyperendemic areas and in those areas where onchocerciasis and loiasis are coendemic. In onchocerciasis-loiasis coendemic areas, vector control methods could provide complementary strategies to accelerate elimination. Study of host-seeking behaviour could inform the development of new control/monitoring tools against vectors. These new tools could be used against vectors of onchocerciasis, vectors of loiasis, or both. Control and monitoring tools, exploiting the natural attraction of hosts, could be implemented by communities and enhance country ownership. To ensure vector control capacity, well-trained, motivated, and appropriately funded local entomologists are essential to lead vector research and entomological operations. [ABSTRACT FROM AUTHOR]

Black flies (Diptera: Simuliidae) are well known as annoying biting pests and vectors of disease-causing agents to humans and other animals. Despite their relevance, no studies have been conducted on Hispaniola for decades. Our work aimed to determine the species composition, relative abundance, breeding sites, phylogenetic relationships, and biting habits of black flies from an important ecotourism spot in La Vega Province (Dominican Republic). Simulium ochraceum sensu lato Walker, Simulium haematopotum Malloch, and Simulium quadrivittatum Loew were identified by both morphological and molecular analyses. Black flies were abundant in most (92% of the total) of the flowing water courses studied and their relative abundance varied depending on the method of collection and type of water course. Simulium haematopotum was prominent in large rivers whereas the other two black fly species were more abundant in streams and ditches. The immature stages were found primarily attached to emergent/submerged riparian vegetation and decaying leaves. Phylogenetic analyses based on the mitochondrial cytochrome c oxidase subunit I (COI) gene revealed that the specimens of S. ochraceum s.l. are divided into three clades, and those from the Dominican Republic formed a group with members from Venezuela, Ecuador, Peru, and Colombia. The S. quadrivittatum COI sequences in this study formed a distinct clade from previous collections in Belize and Costa Rica, which might suggest that they represent a species complex. The S. haematopotum sequences were similar to those reported in other countries. Simulium quadrivittatum was the predominant anthropophilic species (statistically significant) and preferred to bite the lower parts of the body of humans. A comprehensive illustrated description of adults (females and males), pupae, and larvae of the three simuliid taxa is provided. [ABSTRACT FROM AUTHOR]

Abstract Background Besides the considerable role of blackflies to the transmission of many disease agents, these flies considered as annoying biting pests of wildlife, livestock, poultry, and humans. There are few literature reports of blackfly fever following Simulium spp. This study describes a case of blackfly fever and dermatitis following blackflies numerous bites in Iran. Case presentation The present report describes a 25-year-old man that was attacked by numerous flies while fishing and camping near Namrood river in Firuzkuh County, Tehran Province, Iran. Pruritic dermatitis with marked edema appeared mainly on the hands and legs and subsequently, the patient’s condition worsened with swollen lymph nodes, joints aching, and 40 °C fever. The patient’s clinical signs and symptoms were alleviated by injection of intramuscular Dexamethasone Phosphate (DEXADIC®) 8 mg/2 ml after 24 h. Conclusions This study reported a human case with blackfly fever and dermatitis following numerous bites of Simulium kiritshenkoi, for the first time in Iran.

Abstract Background Knowledge of the relative abundance and biting rates of riverine blackflies (vectors of onchocerciasis) is essential as these entomological indices affect transmission of the disease. However, transmission patterns vary from one ecological zone to another and this may be due to differences in species of blackfly vectors and the climatic conditions in the area. This study investigated the effects of climate variability on the relative abundance and biting rates of blackflies in the Tanfiano community (Nkoranza North District, Bono East Region, Ghana). Such information will help to direct policy on effective timing of the annual mass drug administration of ivermectin in the area. Methods The study employed human landing collections and locally built Esperanza window traps to collect blackflies from March 2018 to February 2019. The relative abundance and biting rates of the Simulium vectors as well as the monthly climatic conditions of the study area were monitored. Correlation analysis and Poisson regression were used to establish the relationships between the variables. Results The relative abundance and biting rates of the Simulium vectors were highest in the drier months of March, April and August, characterized by high temperatures, low humidity, longer hours of sunshine and stronger winds. The rainy months of May, June and July, characterized by low temperatures, high humidity, few hours of sunshine and weaker winds, had relatively low blackfly abundance and biting activity. Correlation analysis showed that only temperature was significantly, positively correlated with the relative abundance of blackflies (r = 0.617, n = 12, P = 0.033) and monthly biting rates (r = 0.612, n = 12, P = 0.034). A model to predict relative abundance and monthly biting rates using climatological variables was developed. Conclusions This study demonstrated that Simulium species in the study area preferred higher temperature, lower humidity and rainfall, more hours of sunshine and relatively stronger winds for survival. It is thus recommended that for the study district and others with similar climatological characteristics, mass drug administration of ivermectin should take place in April and September when the abundance of vectors has begun to decline after peaking.

Nodding syndrome is one of several forms of onchocerciasis-associated epilepsy (OAE) seen among children in areas formerly hyperendemic for the transmission of Onchocerca volvulus. These forms of epilepsy are highly prevalent and clustered in certain villages located close to blackfly (Diptera: Simuliidae) breeding sites. OAE presents with a wide spectrum of seizures, including generalized tonic-clonic and head nodding seizures, impaired cognitive function, growth stunting and delayed puberty. In 2014, the present authors published a perspective paper in this journal which hypothesized that nodding syndrome may be caused by either a neurotropic virus transmitted by blackflies or an endosymbiont present within the O. volvulus parasite. Seven years later, this critical review presents progress in nodding syndrome research, and assesses whether it is still plausible that a neurotropic virus or endosymbiont could be the cause.

Onchocerciasis is a neglected tropical disease (NTD) caused by Onchocerca Diesing 1841 (Spirurida: Onchocercidae) nematodes transmitted by blackflies. It is associated with poverty and imposes a significant health, welfare and economic burden on many tropical countries. Current methods to visualize infections within the vectors rely on invasive methods. However, using micro‐computed tomography techniques, without interference from physical tissue manipulation, we visualized in three dimensions for the first time an L1 larva of an Onchocerca species within the thoracic musculature of a blackfly, Simulium damnosum s.l. Theobald 1903 (Diptera: Simuliidae), naturally infected in Ghana. The possibility that thicker peritrophic membranes in savannah flies could account for their lower parasite loads was not supported, but there were limits to our analysis. While there were no statistically significant differences between the mean thicknesses of the peritrophic membranes, in the anterior, dorsal and ventral regions, of forest and savannah blackflies killed 34–48 min after a blood‐meal, the thickness of the peritrophic membrane in the posterior region could not be measured. Micro‐computed tomography has the potential to provide novel information on many other parasite/vector systems and impactful images for public engagement in health education. [ABSTRACT FROM AUTHOR]

Abstract Background Onchocerciasis, or river blindness, is a dermal filariasis caused by infection with the nematode parasite Onchocerca volvulus, transmitted to humans through the bites of blackflies of the genus Simulium. Despite the decade-long West African Regional Programme for the Elimination of Onchocerciasis, involving the mass administration of ivermectin to populations in endemic areas, recrudescence has occurred. An example is in the Cascades Region of south-west Burkina Faso where the resumption of transmission had resulted in infection prevalences of up to 70% in some villages. In 2011, a strategy for community-directed distribution of ivermectin (CDTI) was set up to respond to this worrying re-emergence. Here, we report on a study of Onchocerca spp. transmission in the affected area carried out from January to December 2012. Every month, host-seeking adult females of the S. damnosum complex were collected at sites on the River Comoé near the four villages (Bodadiougou, Bolibana, Badara Karaboro and Badara Dogossè) that had recorded the highest prevalences in 2010. Collected blackflies were dissected and infective larvae were identified using the O-150 PCR method. Results A total of 9114 S. damnosum (s.l.) adult females were collected, of which 5142 were parous (56.4%) and 78 (1.51%) were infective carrying a total of 137 infective larvae. The annual transmission potential (ATP) was calculated as 0, 30, 255 and 771 infective larvae/man/year in Badara Dogossè, Bolibana, Badara Karaboro and Bodadiougou, respectively. Transmission levels in the latter two are of particular concern as they were higher than 100 infective larvae/person/year, the designated minimum threshold required for elimination of severe pathology, including damage to vision. Conclusions These results confirm that recrudescence of onchocerciasis has occurred, and that transmission of O. volvulus was active at sites on the Comoé River in the Cascades region in 2012. In accordance with WHO recommendations, CDTI should be continued and the situation in the Cascades region should be closely monitored if further spread of this outbreak is to be avoided.

Objective: To determine whether dogs are at variable risk of developing canine ocular onchocerciasis based on coat color or size, factors that may influence feeding behavior of the putative vectors of Onchocerca lupi¸ the filarial nematode parasite causing this disease. Animals studied: One hundred twenty‐five client‐owned dogs diagnosed with confirmed or suspected onchocerciasis. 1255 dogs without signs of this disease were utilized for comparison. Procedures: Dogs lacking signs of canine onchocerciasis were assessed for coat color and weight. Proportions of dogs with these characteristics were used to predict signalment in a group of dogs with this disease, if the investigated characteristics were unrelated to disease risk. Predicted values were compared statistically with observed values in the diseased dog population. Black fly color preference was assessed utilizing black, brown, and white traps and statistically assessing any differences in trapping based on trap color. Results: Results suggest that large, black dogs are more likely to develop canine ocular onchocerciasis than was predicted by chance alone (p = 0.012). Results for smaller dogs with other coat colors were not significant. An increased risk for black dogs was supported by trapping data, as black flies were trapped significantly more often in black traps (p < 0.001). Conclusion: While factors other than size and color probably also influence the likelihood of O. lupi infection and disease development, our results may assist clinicians in their diagnosis of canine ocular onchocerciasis and provide them with a tool to help educate their clients as to their dogs' risk of developing this disease. [ABSTRACT FROM AUTHOR]

Sexually anomalous individuals, typically intersexes or gynandromorphs, bear a mixture of male and female traits. Twelve sexually anomalous individuals of the black fly Simulium (Gomphostilbia) trangense Jitklang, Kuvangkadilok, Baimai, Takaoka & Adler were discovered among 49 adults reared from pupae. All 12 sexually anomalous adults were parasitized by mermithid nematodes, although five additional parasitized adults had no overt external anomalies. Sequence analysis of the 18S rRNA gene revealed that the mermithids, possibly representing a new species, are related to Mesomermis spp., with genetic distances of 5.09–6.87%. All 12 anomalous individuals had female phenotypical traits on the head, thorax, forelegs, midlegs, and claws, but male features on the left and right hind basitarsi. One individual had mixed male and female genitalia. The findings are in accord with the trend that mermithid infections are associated with sexually anomalous adult black flies. [ABSTRACT FROM AUTHOR]

Abstract Background Insect bite hypersensitivity (IBH) is an IgE-mediated dermatitis caused by bites of Culicoides spp., which occurs frequently in horses imported from Iceland to continental Europe. IBH does not occur in Iceland because Culicoides species that bite horses are not present. However, Simulium vittatum (S. vittatum) are found in Iceland. In Europe, blood basophils from IBH-affected horses release significantly more sulfidoleukotrienes (sLT) than those from healthy controls after in vitro stimulation with Culicoides nubeculosus (C. nubeculosus) and S. vittatum. Aims of the study were: (I) using the sLT release assay, to test if horses living in Iceland were sensitized to S. vittatum and (II) to determine in a longitudinal study in horses imported from Iceland to Switzerland whether the sLT release assay would allow to predict which horses would develop IBH. Results Horses in Iceland, even when living in high S. vittatum areas, were usually not sensitized to S. vittatum or C. nubeculosus. Incidence of IBH in the 145 horses from the longitudinal study was 51% and mean time until IBH developed was 2.5 ± 1 year. Before import and after the first summer following import, there were no significant differences in sLT release between the endpoint healthy (H) and IBH groups. After the 2nd summer, when the number of clinically affected horses increased in the endpoint IBH group, a significantly higher sLT release after stimulation with C. nubeculosus but not with S. vittatum was observed. After the 3rd and 4th summer, the endpoint IBH group had a significantly higher sLT release with C. nubeculosus and S. vittatum than the endpoint H group. Some of the horses that remained healthy became transiently positive in the sLT release assay upon stimulation of their peripheral blood leucocytes with C. nubeculosus. Conclusions Horses in Iceland are not sensitized to S. vittatum. In horses that develop IBH, sensitization to S. vittatum is secondary to sensitization to C. nubeculosus and probably a result of an immunological cross-reactivity. A sLT release assay cannot be used to predict which horses will develop IBH. A transient positive reaction in the sLT release assay observed in horses that remained healthy suggests that immunoregulatory mechanisms may control an initial sensitization of the healthy horses.

Background: Besides the considerable role of blackflies to the transmission of many disease agents, these flies considered as annoying biting pests of wildlife, livestock, poultry, and humans. There are few literature reports of blackfly fever following Simulium spp. This study describes a case of blackfly fever and dermatitis following blackflies numerous bites in Iran.Case Presentation: The present report describes a 25-year-old man that was attacked by numerous flies while fishing and camping near Namrood river in Firuzkuh County, Tehran Province, Iran. Pruritic dermatitis with marked edema appeared mainly on the hands and legs and subsequently, the patient's condition worsened with swollen lymph nodes, joints aching, and 40 °C fever. The patient's clinical signs and symptoms were alleviated by injection of intramuscular Dexamethasone Phosphate (DEXADIC®) 8 mg/2 ml after 24 h.Conclusions: This study reported a human case with blackfly fever and dermatitis following numerous bites of Simulium kiritshenkoi, for the first time in Iran. [ABSTRACT FROM AUTHOR]

Background: Knowledge of the relative abundance and biting rates of riverine blackflies (vectors of onchocerciasis) is essential as these entomological indices affect transmission of the disease. However, transmission patterns vary from one ecological zone to another and this may be due to differences in species of blackfly vectors and the climatic conditions in the area. This study investigated the effects of climate variability on the relative abundance and biting rates of blackflies in the Tanfiano community (Nkoranza North District, Bono East Region, Ghana). Such information will help to direct policy on effective timing of the annual mass drug administration of ivermectin in the area. Methods: The study employed human landing collections and locally built Esperanza window traps to collect blackflies from March 2018 to February 2019. The relative abundance and biting rates of the Simulium vectors as well as the monthly climatic conditions of the study area were monitored. Correlation analysis and Poisson regression were used to establish the relationships between the variables. Results: The relative abundance and biting rates of the Simulium vectors were highest in the drier months of March, April and August, characterized by high temperatures, low humidity, longer hours of sunshine and stronger winds. The rainy months of May, June and July, characterized by low temperatures, high humidity, few hours of sunshine and weaker winds, had relatively low blackfly abundance and biting activity. Correlation analysis showed that only temperature was significantly, positively correlated with the relative abundance of blackflies (r = 0.617, n = 12, P = 0.033) and monthly biting rates (r = 0.612, n = 12, P = 0.034). A model to predict relative abundance and monthly biting rates using climatological variables was developed. Conclusions: This study demonstrated that Simulium species in the study area preferred higher temperature, lower humidity and rainfall, more hours of sunshine and relatively stronger winds for survival. It is thus recommended that for the study district and others with similar climatological characteristics, mass drug administration of ivermectin should take place in April and September when the abundance of vectors has begun to decline after peaking. [ABSTRACT FROM AUTHOR]

Considerando la importancia de Simulium sp. como posible vector de Onchocerca volvulus, parásito causante de la oncocercosis, y teniendo en cuenta que el análisis de los cromosomas politénicos se ha convertido en un herramienta poderosa para la identificación y clasificación de la poblaciones vectoras o no vectoras; se realizó un estudio preliminar basado en la estandarización de la técnica de extracción de los cromosomas politénicos y la caracterización de estos para individuos del género Simulium sp. encontrados en la quebrada la Aldana de la Reserva Natural de Cedro Rosado, Quindío. Los resultados del estudio indicaron que la especie tiene una dotación n=3. La longitud relativa es 125 micras, de las cuales el 46% corresponde al cromosoma I, el 33% al cromosoma II y el 21% al cromosoma III del complemento total. Los cromosomas I y II son submetacéntricos y el III metacéntrico. Se identifican los marcadores cromosómicos en la especie estudiada y un índice asimétrico=0,51.

Abstract Background Blackflies are an important medical and veterinary group of small blood-sucking insects. Ninety-three blackfly species have been reported in Thailand. However, information on their biodiversity and population dynamics in each region is lacking. The main aim of this study was to assess the regional biodiversity, seasonal abundance and distribution of blackflies in six eco-geographically different regions in the country. Methods Blackfly larvae and pupae were sampled monthly from 58 sites between May 2011 and April 2013. Diversity parameters, seasonal abundance, regional distribution and frequency of species occurrence in stream sites were analyzed. Results A total of 19,456 mature larvae representing 57 species, and belonging to six subgenera in the genus Simulium Latreille (s.l.), were found. The five predominant taxa were S. fenestratum (8.6%), the S. asakoae complex (8.3%), S. nakhonense (7.5%), the S. siamense complex (7.4%) and the S. doipuiense complex (6.7%). The most frequent taxa at all sites were the S. asakoae complex (84.5%), followed by S. fenestratum (82.8%), the S. siamense complex (75.9%), S. decuplum (60.3%), S. nakhonense (58.6%) and the S. tani complex (48.3%). The richness of regional species was highest (40 species) in the north and predominated in the cold season. However, blackflies in the south predominated during the hot season. The highest numbers of blackflies collected from central, northeastern, eastern and western regions of the country were observed in the rainy season. Overall, the mean number of blackflies collected across the six regions during the rainy and cold season had no statistically significant difference, but it differed significantly in the hot season. Conclusions Blackflies in Thailand were surveyed in all three seasons across six geographical regions. These findings demonstrated that blackfly communities at each stream site varied with seasonality, and the regional relative abundance of blackflies differed markedly in the hot season. It was also found that the occurrence and distribution of blackflies in each region were associated strongly with elevation.

Background & objectives: Black flies (Diptera: Simuliidae) are ecologically and medically important insects. Female adults of black flies are the solitary vectors of river blindness (onchocerciasis) and their larvae play a vital role in stream ecosystem. This study examined the distribution of black flies in the Oriental region and analyzed the phylogenetic relationship of the subgenus Gomphostilbia members based on two molecular loci. Methods: The distribution data of black fly species in different countries of Oriental region were obtained from world black flies geographic inventory. The two gene sequences, COI and ITS1 were used to study the phylogenetic relationships of the members of subgenus Gomphostilbia members. Results: The distribution analysis revealed that out of the 16 subgenera in the genus Simulium Latreille s., the species-level diversity of three subgenera (Gomphostilbia, Nevermannia and Simulium) contributes about thrice of total black fly species diversity. The highest diversity of species was found in the subgenus Simulium. The strict consensus of Tree analysis using New Technology (TNT) and Maximum Likelihood (ML) recovered similar topologies for Gomphostilbia members and they formed as monophyly. The overall sequence identities of the 19 species of subgenus Gomphostilbia were high and shared 55–60% similarity. Interpretation & conclusion: Results of this study highlighted that eight subgenera of Simulium Latreille s. str are commonly distributed in different parts of Oriental region. Among these the subgenera of Simulium, Gomphostilbia and Nevermannia are most common with high diversity in China, Pakistan, Thailand and Vietnam. The phylogenetic analysis of Gomphostilbia members demonstrates the inter-specific divergence, indicating the centre of origin (India) or the recipient of ancestral migrant lineages in Oriental region.

Black flies form a group of small blood-sucking insects of medical and veterinary importance. This study aimed to investigate the community structure, biodiversity and spatial and temporal distribution of adult black flies in tropical rain forests, by using malaise traps in Doi Inthanon National Park, northern Thailand. Malaise traps were placed along six elevational gradients (400 m to 2500 m, above sea level) at Doi Inthanon National Park, Chiang Mai province, from December 2013 to November 2014. A total of 9406 adult female black flies belonging to five subgenera—Daviesellum (2%), Gomphostilbia (23%), Montisimulium (11%), Nevermannia (16%) and Simulium (48%)—were collected. Among 44 taxa found, S. tenebrosum complex had the highest relative abundance (11.1%), followed by the S. asakoae species-group (9.6%), the S. striatum species-group (7.7%), S. inthanonense (6.6%), S. doipuiense complex (6.4%), S. chomthongense complex (5.3%), S. chumpornense (5.1%) and S. nigrogilvum (4.1%). Two human-biting species—S. nigrogilvum and species in the S. asakoae species-group—were found in all of the collection sites with 100% species occurrence. Species richness was highest at mid elevation (1400 m), which is represented by 19 black fly species. The peak and lowest seasonal abundance was observed in the rainy and hot season, respectively. Seasonal species richness was highest in the cold season, except for that from elevation sites at 700 m, 1700 m and 2500 m. This study revealed that the malaise trap is effective in providing important data for further monitoring of the effects of environmental changes and conservation planning on the biodiversity of black flies in Doi Inthanon National Park.

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• Genetic diversity of three human-biting black fly species was examined. • DNA barcoding sequences indicate cryptic diversity in these human-biting black flies. • New records for human-biting black fly species in Thailand were revealed based on DNA barcode. Black flies (Simuliidae) are important biting insects and vectors of diseases agents of humans and livestock. Thus, understanding the taxonomy and biodiversity of these insects is crucial for control and management of these diseases. In this study, we used mitochondrial cytochrome c oxidase I sequences to examine genetic diversity of three human-biting and possible vector black fly taxa; the Simulium asakoae species-complex, S. chamlongi and S. nigrogilvum. High levels of genetic diversity (>3.5% intraspecific genetic divergence) were found in all three taxa. Phylogenetic analyses indicated that the S. asakoae complex can be divided into seven groups with the largest group consisting of specimens from Thailand, Malaysia and Myanmar. This group most likely represents true S. asakoae. The remaining haplotypes formed groups with conspecific haplotypes or with other closely related species. Among these groups, one including S. monglaense and another including S. myanmarense suggest that certain specimens identified as S. asakoae most likely belong to those species. Therefore, they constitute new locality records for Thailand and also represent new records of anthropophily. Members of S. chamlongi are not monophyletic as its clade also included S. hackeri. A median joining network revealed strong geographic associations of the haplotypes of S. nigrogilvum suggesting limitation of gene flow. Because this species occurs mainly in high elevation habitats, low land areas could present a barrier to gene flow. [ABSTRACT FROM AUTHOR]

Simulium (Gomphostilbia) agasthyamalaiense sp. nov. is described based on adults, pupae and mature larvae from a medium-flowing stream of Southern Western Ghats, India. This new species is placed in the Simulium batoense species-group of the subgenus Gomphostilbia Enderlein. This new species is characterized in the female by a scutum with three brownish-black longitudinal vittae and the hind basitarsus 5.7 times as long as wide; in the female by the large facets of upper eye with 20 vertical columns and 19 horizontal rows; in the pupa the respiratory gill with medium-long common basal stalk; and in the larva arrowhead-shaped postgenal cleft. Taxonomic notes are provided for this new species and it can be distinguished from closely related species of S. (G.) peteri. Keys are constructed to distinguish this species from ten species of the batoense species-group recorded in India. www.zoobank.org/urn:lsid:zoobank.org:pub:1D1CFEE5-A762-4F68-9EAE-9E31133146C0 Unlabelled Image • A new black fly species of the Simulium (Gomphostilbia) is described from India. • Morphological descriptions and taxonomic notes of S. (G.) agasthyamalaiense sp. n., are given adults, pupae and larvae. • Keys are constructed for the members in batoense -species group of Gomphostilbia of India. [ABSTRACT FROM AUTHOR]

Abstract Simulium (Gomphostilbia) aziruni Takaoka, Hashim & Chen was described initially based only on a pupa and a mature larva collected from Peninsular Malaysia. Herein, we describe the morphological characters of the female of S. aziruni for the first time. It resembles those of the other members of the Simulium gombakense species-group by the genital fork with a distinct projection directed medioposteriorly from each arm and claw with a large basal tooth. Cytochrome c oxidase I (COI) barcoding analysis indicates that S. aziruni is the sister species of S. maleewongae , but both are distantly separated by a genetic distance of 4.9%. [ABSTRACT FROM AUTHOR]

Simulium (Simulium) yanaense sp. nov. is described based on the male, larva, and pupa. It is characterized by having a maxillary palp with a small sensory vesicle, and the subcosta and basal portion of the radius bare in the male; the gill with 10 short slender filaments and short common basal stalk in the pupa; and the thorax and abdomen without a pair of dorsolateral protuberances in the larva. Keys are provided to the species of the S. striatum species group of the subgenus Simulium known from India. [ABSTRACT FROM AUTHOR]