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1.
Acta Trop ; 250: 107097, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38097150

ABSTRACT

Mitochondrial cytochrome c oxidase subunit I (COI) sequences were utilized to infer the population genetic structure of Simulium (Gomphostilbia) atratum De Meijere, an endemic simulid species to Indonesia. Both median-joining haplotype network and maximum-likelihood tree revealed two genetic lineages (A and B) within the species, with an overlap distribution in Lombok, which is situated along Wallace's line. Genetic differentiation and gene flow with varying frequencies (FST = 0.02-0.967; Nm = 0.01-10.58) were observed between populations of S. (G.) atratum, of which population pairs of different lineages showed high genetic differentiation. Notably, the high genetic distance of up to 5.92 % observed within S. (G.) atratum in Lombok was attributed to the existence of two genetically distinct lineages. The co-occurrence of distinct lineages in Lombok indicated that Wallace's line did not act as faunistic border for S. (G.) atratum in the present study. Moreover, both lineages also exhibited unimodal distributions and negative values of neutrality tests, suggesting a pattern of population expansion. The expansion and divergence time estimation suggested that the two lineages of S. (G.) atratum diverged and expanded during the Pleistocene era in Indonesia.


Subject(s)
Simuliidae , Animals , Indonesia , Simuliidae/genetics , Mitochondria , Phylogeny , Genetic Variation
2.
J Med Entomol ; 60(6): 1330-1342, 2023 11 14.
Article in English | MEDLINE | ID: mdl-37669777

ABSTRACT

Simulium (Asiosimulium) khongchiamense sp. nov. is described based on females, males, pupae, and mature larvae collected from Khong Chiam District, Ubon Ratchathani Province, northeastern Thailand. It is characterized in the female by the medium-long sensory vesicle, scutum with 3 dark longitudinal vittae and elongate cercus; in the male by the number of upper-eye (large) facets in 17 or 18 vertical rows and 18 or 19 horizontal rows, hind basitarsus moderately enlarged and ventral plate with the posterior margin moderately concave medially; in the pupa by the head and thoracic integument sparsely covered with tubercles and gill of arborescent type with 32 or 33 filaments; and in the larva by the postgenal cleft deep, reaching the posterior margin of the hypostoma and sheath of the subesophageal ganglion dark pigmented. DNA analysis based on COI gene of all known species of the subgenus Asiosimulium, except for S. shanense and S. suchitrae, indicated that this new species can be clearly differentiated from all other related species (S. phurueaense, S. oblongum, S. saeungae, S. furvum, and S. wanchaii) with interspecific genetic distances ranging between 4.79% and 19.18%. This is the eighth species of the subgenus Asiosimulium. Taxonomic notes are given to distinguish this new species from the 7 known species members in its same subgenus. Additionally, keys to species of all members in the subgenus Asiosimulium are provided.


Subject(s)
Simuliidae , Male , Female , Animals , Simuliidae/genetics , Phylogeny , Thailand , Larva/genetics , Pupa/genetics
3.
Front Immunol ; 14: 1163367, 2023.
Article in English | MEDLINE | ID: mdl-37469515

ABSTRACT

Background: Salivary glands from blood-feeding arthropods secrete several molecules that inhibit mammalian hemostasis and facilitate blood feeding and pathogen transmission. The salivary functions from Simulium guianense, the main vector of Onchocerciasis in South America, remain largely understudied. Here, we have characterized a salivary protease inhibitor (Guianensin) from the blackfly Simulium guianense. Materials and methods: A combination of bioinformatic and biophysical analyses, recombinant protein production, in vitro and in vivo experiments were utilized to characterize the molecula mechanism of action of Guianensin. Kinetics of Guianensin interaction with proteases involved in vertebrate inflammation and coagulation were carried out by surface plasmon resonance and isothermal titration calorimetry. Plasma recalcification and coagulometry and tail bleeding assays were performed to understand the role of Guianensin in coagulation. Results: Guianensin was identified in the sialotranscriptome of adult S. guianense flies and belongs to the Kunitz domain of protease inhibitors. It targets various serine proteases involved in hemostasis and inflammation. Binding to these enzymes is highly specific to the catalytic site and is not detectable for their zymogens, the catalytic site-blocked human coagulation factor Xa (FXa), or thrombin. Accordingly, Guianensin significantly increased both PT (Prothrombin time) and aPTT (Activated partial thromboplastin time) in human plasma and consequently increased blood clotting time ex vivo. Guianensin also inhibited prothrombinase activity on endothelial cells. We show that Guianensin acts as a potent anti-inflammatory molecule on FXa-induced paw edema formation in mice. Conclusion: The information generated by this work highlights the biological functionality of Guianensin as an antithrombotic and anti-inflammatory protein that may play significant roles in blood feeding and pathogen transmission.


Subject(s)
Hemostatics , Simuliidae , Mice , Humans , Animals , Endothelial Cells , Hemostasis , Anti-Inflammatory Agents/pharmacology , Inflammation , Salivary Proteins and Peptides/pharmacology , Mammals
4.
Acta Trop ; 244: 106947, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37196907

ABSTRACT

A new black fly species, Simulium (Gomphostilbia) wijiti, is described based on adult females, males, pupal exuviae and mature larvae from Mae Hong Son Province, Thailand. This new species is placed in the Simulium ceylonicum species-group. It is distinguished from four Thai members of the S. ceylonicum species-group [S. (G.) curtatum Jitklang et al., S. (G.) pangsidaense Takaoka, Srisuka & Saeung, S. (G.) sheilae Takaoka & Davies, and S. (G.) trangense Jitklang et al.], in the female by the short to medium long sensory vesicle; in the male by the large number of upper-eye (large) facets in 15 vertical columns and 15 or 16 horizontal rows; in the pupa by the dorsum of abdominal segments darkened; and in the larva by the antenna as long as or slightly shorter than the stem of the labral fan (longer than the stem of the labral fan in four other species). Phylogenetic analysis based on the COI gene sequences revealed that this new species is genetically closely related to S. leparense of the S. ceylonicum species-group, but is clearly separated from the latter species, and also from the three Thai related species (S. curtatum, S. sheilae and S. trangense) of the same species-group with interspecific genetic distances ranging from 9.65% to 12.67%. This is the fifth member of the S. ceylonicum species-group recorded from Thailand.


Subject(s)
Simuliidae , Animals , Female , Male , Thailand , Phylogeny , Larva , Pupa
5.
Med Vet Entomol ; 37(1): 47-62, 2023 03.
Article in English | MEDLINE | ID: mdl-36762479

ABSTRACT

Problems related to the identity of Simuliidae species are impediments to effective disease control in Amazonia. Some of these species, such as Simulium oyapockense Floch & Abonnenc, 1946 (Diptera: Simuliidae), are vectors of the organisms that cause onchocerciasis and mansonellosis diseases. This blackfly species has a wide distribution in South America, and it is suspected of being a complex of cryptic species. The aim of this study is to characterize the nominal species S. oyapockense using partial COI gene sequences. Seven populations of S. oyapockense (morphologically identified) were analysed, including one from its type-locality. The other six populations were collected in Brazil and in Argentina. A taxon collected in Amazonas state, Brazil, with adults similar to S. oyapockense but with distinct pupae, was also included in the analysis (Simulium 'S'). The nominal species S. oyapockense is circumscribed, and its geographical distribution is restricted to areas north of the Amazon River. Populations of S. oyapockense s.l. collected south of the Amazon River comprise a species complex that needs to be evaluated using integrative taxonomy. Simulium 'S' represents a species with unique morphological and molecular characteristics. Distinguishing cryptic species is a prerequisite for reducing the taxonomic impediment, especially in medically important taxa.


Subject(s)
Onchocerciasis , Simuliidae , Animals , Simuliidae/genetics , Simuliidae/anatomy & histology , Insect Vectors , Onchocerciasis/veterinary , Brazil , Argentina
6.
Parasitol Int ; 94: 102733, 2023 Jun.
Article in English | MEDLINE | ID: mdl-36693472

ABSTRACT

Mermithids are the most common parasites of black flies and are associated with host feminization and sterilization in infected hosts. However, information on the species / lineage of black fly mermithids in Southeast Asia, including Malaysia requires further elucidation. In this study, mermithids were obtained from black fly larvae collected from 138 freshwater stream sites across East and West Malaysia. A molecular approach based on nuclear-encoded 18S ribosomal RNA (18S rRNA) gene was used to identify the species identity / lineage of 77 nematodes successfully extracted and sequenced from the specimens collected. Maximum likelihood and neighbor-joining phylogenetic analyses demonstrated five distinct mermithid lineages. Four species delimitation analyses: automated simultaneous analysis phylogenetics (ASAP), maximum likelihood Poisson tree processes with Bayesian inferences (bPTP_ML), generalized mixed yule coalescent (GMYC) and single rate Poisson tree processes (PTP) were applied to delimit the species boundaries of mermithid lineages in this data set along with genetic distance analysis. Data analysis supports five distinct lineages or operational taxonomic units for mermithids in the present study, with two requiring further investigation as they may represent intraspecific variation or closely related taxa. One mermithid lineage was similar to that previously observed in Simulium nigrogilvum from Thailand. Co-infection with two mermithids of different lineages was observed in one larva of Simulium trangense. This study represents an important first step towards exploring other aspects of host - parasite interactions in black fly mermithids.


Subject(s)
Mermithoidea , Simuliidae , Animals , Simuliidae/parasitology , Rivers , Malaysia/epidemiology , Phylogeny , Bayes Theorem , Larva
7.
Tropical Biomedicine ; : 88-100, 2023.
Article in English | WPRIM (Western Pacific) | ID: wpr-1006545

ABSTRACT

@#Simulium (Gomphostilbia) okinawense Takaoka and S. (G.) tokarense Takaoka, both from the Nansei Islands, Japan, were morphologically reexamined and genetically analysed by using the COI gene sequences. The female, male, pupa and mature larva of the two species are redescribed. Morphological reexamination shows that both species are more similar to species in the S. asakoae species-group than to those in the S. ceylonicum species-group, by having a medium-long female sensory vesicle, yellow tuft hairs (S. (G.) okinawense) or yellow tuft hairs mixed with a few to several dark hairs (S. (G.) tokarense) at the base of the radial vein in the female and male, and medium-long larval postgenal cleft. However, the body of the male ventral plate (viewed ventrally) is parallel-sided (S. (G.) okinawense) or parallelsided or slightly narrowed (S. (G.) tokarense) and not emarginated basally, differing from those of most species in the S. asakoae species-group. Our genetic analysis shows that S. (G.) tokarense is in the S. asakoae species-group, and S. (G.) okinawense formed a separate sister clade with other members of the S. asakoae species-group with high bootstrap support. From the results of morphological and genetic analysis combined, S. (G.) okinawense and S. (G.) tokarense are transferred from the S. ceylonicum species-group to the S. asakoae species-group.

8.
Tropical Biomedicine ; : 266-272, 2023.
Article in English | WPRIM (Western Pacific) | ID: wpr-1006803

ABSTRACT

@#Simulium takahasii (Rubtsov), which was originally described from Japan, and recorded from Korea and China, is the first among the 19 species of the subgenus Wilhelmia Enderlein recorded from East Asia. It is striking in mating, blood-feeding and ovipositing in captivity and in experimentally transmitting Dirofilaria immitis (Leidy) and Brugia pahangi (Buckley & Edeson), and it is a severe biter of cattle and horses, rarely of humans. Nevertheless, updated information about its morphological characteristics was lacking, making comparisons with related species described from China difficult, since species of the subgenus Wilhelmia are almost indistinguishable from one another, in particular, in their female terminalia, male genitalia and most of larval features. In this study, as many morphological characteristics as possible of S. takahasii based on specimens from Japan are redescribed. New information about many features of this species including the length of the female sensory vesicle against the third palpal segment, number of male upper-eye (large) facets, arrangement of the eight pupal gill filaments, presence or absence of tiny dark setae on the dorsum of the larval abdomen and the number of rows and hooklets of the larval posterior circlet will be useful in evaluating the species status of several Wilhelmia species in China including the species regarded as S. takahasii.

9.
Acta Trop ; 230: 106387, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35227649

ABSTRACT

Simulium (Simulium) thilorsuense sp. nov. is described from females, males, pupae and mature larvae in Thailand. It is placed to the S. striatum species-group, and is distinguished from all the seven species of this species-group recorded from Thailand in the male by the greater number of male upper-eye (large) facets in 20 vertical columns and 19 or 20 horizontal rows, and in the pupa by the combination of the arrangement (2+3+3+2 from dorsal to ventral) and subequal thickness of gill filaments, and tubercles on the frons without secondary projection. It is similar in the female, male and pupa to S. (S.) pingtungense Huang & Takaoka from Taiwan but is distinguished in the larva by the presence of paired protuberances on abdominal segments 1-8 (absence in the latter species). It is similar to S. (S.) grisescens Brunetti from India, S. (S.) perakense Takaoka &Ya'cob from Peninsular Malaysia, and S. (S.) taythienense Takaoka, Sofian-Azirun & Ya'cob from Vietnam by sharing many characteristics including the haired basal portion of the female radius, dark legs of both female and male, male scutum with brassy short hairs, pupal gill with 10 filaments of the almost same thickness, arranged as 2+3+3+2 from dorsal to ventral, and larval abdomen with paired dorsal protuberances, but is distinguished from these three species by the greater number of male upper-eye (large) facets. Our genetic analysis using the fast-evolving nuclear big zinc finger (BZF) gene sequences revealed that this new species has an intraspecific variation ranging from 0.00% to 1.38%, and is separated from six Thai known species of the S. striatum species-group with an interspecific variation of 2.00-4.56%.


Subject(s)
Simuliidae , Animals , Female , Larva/genetics , Male , Phylogeny , Pupa/genetics , Simuliidae/genetics , Thailand
10.
Acta Trop ; 228: 106313, 2022 Apr.
Article in English | MEDLINE | ID: mdl-35038426

ABSTRACT

Adult females and males reared from pupae of Simulium sp. from Tak Province and those of S. chiangdaoense Takaoka & Srisuka from four localities in Chiang Mai and Lampang Provinces, northern Thailand, were molecularly and morphologically compared. Simulium sp. is morphologically almost indistinguishable from S. chiangdaoense except the hair tuft at the base of the radius of the adult female and male, which is composed of yellow and dark hairs (in place of yellow hairs only). Molecular analysis using COI gene sequences shows that S. sp. formed a distinct clade and was separated from S. chiangdaoense by a genetic distance of 1.56-2.44%. Based on the results of morphological and molecular analyzes, S. sp. is described as a new species, S. mokroense, from females, males, pupae and mature larvae. It is also found that S. chiangdaoense is genetically diverse, with five lineages, and is morphologically variable in the number of male upper-eye (large) facets, which are in 13 to 17 vertical columns and 14 to 17 horizontal rows on each side. This is a first case, in which the difference in the color of the wing tuft hairs is a clue leading to the discovery of a new cryptic species close to S. chiangdaoense.


Subject(s)
Simuliidae , Animals , Female , Larva/anatomy & histology , Male , Phylogeny , Pupa/anatomy & histology , Pupa/genetics , Thailand
11.
Tropical Biomedicine ; : 451-454, 2022.
Article in English | WPRIM (Western Pacific) | ID: wpr-961125

ABSTRACT

@#Simulium (Wallacellum) tuyense Takaoka, one of the 14 Philippine species in the subgenus Wallacellum Takaoka, is a rare species in having the pupal antennal sheath with a row of stout spines on the apex of each protuberance corresponding to flagellomeres 2–9. The female of this species is described for the first time based on specimens from Mindoro, the Philippines. It is characterized by an elongate sensory vesicle, triangular ovipositor valve, genital fork with two projections, and paraproct not produced anteriorly. This species is morphologically indistinguishable in the female, as in the male and pupa, from S. (W.) yonakuniense Takaoka from Yonakuni Island, Japan and Lanyu Island, Taiwan. Taxonomic notes on the female of this species relevant to those of related species are provided. Collection data to validate earlier distribution records of S. (W.) tuyense and S. (W.) suyoense Takaoka from Mindanao are presented.

12.
Acta Trop ; 225: 106207, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34687650

ABSTRACT

Simulium (Gomphostilbia) omutaense Ogata & Sasa, 1954 is the only named species in the Simulium batoense species-group of the subgenus Gomphostilbia Enderlein recorded from Honshu and Kyushu, Japan. It represents the northernmost distribution of this species-group, of which most members are distributed in the Oriental region. This species, the only member of the Simulium omutaense subgroup, is unique among the seven subgroups of the S. batoense species-group by having the pupal gill with one long filament and seven short filaments, similar to the arrangement of the pupal gill filaments in the S. zonatum subgroup of the S. epistum species-group in the same subgenus. This species is fully redescribed based on adults, pupal exuviae and mature larvae, and is most similar to species of the S. decuplum subgroup, based on adult morphological characteristics, although the pupal gill of the latter subgroup is markedly different by having 10 or 12 short filaments. Its close relationship to the S. decuplum subgroup is supported by a DNA analysis using COI gene sequences, with genetic distances of 9.30-11.02%. On the other hand, genetic distances between S. (G.) omutaense and species of the S. zonatum subgroup were 16.32-16.93%. Our study shows that a similar arrangement of the pupal gills in two different species-groups, which is rarely seen, has evolved independently and its occurrence does not necessarily reflect phylogenetic relationships.


Subject(s)
Sasa , Simuliidae , Animals , Japan , Larva , Phylogeny , Pupa , Simuliidae/genetics
13.
Tropical Biomedicine ; : 332-337, 2022.
Article in English | WPRIM (Western Pacific) | ID: wpr-940254

ABSTRACT

@#The males of Simulium (Gomphostilbia) miblosi Takaoka in the S. epistum species-group, and S. (G.) apoense Takaoka in the S. ceylonicum species-group, both from Mindanao, the Philippines, are described for the first time. The male of S. (G.) miblosi is characterized by the hind tibia yellowish white on the basal three-fifths, elongate calcipala 1.5 times as long as its basal width, and ventral plate triangular ventrally (0.74 times as high as its greatest width) when viewed caudally. Tubercles on the frons and trichomes on the head and thorax of the pupa of this species are illustrated for the first time. The male of S. (G.) apoense is characterized by the small sensory vesicle 0.16–0.19 times as long as the third palpal segment, and enlarged hind basitarsus 1.0 and 1.2–1.3 times as wide as the hind tibia and femur, respectively. Taxonomic notes of these two species relevant to related species in each species-group are given.

14.
Tropical Biomedicine ; : 60-65, 2022.
Article in English | WPRIM (Western Pacific) | ID: wpr-936398

ABSTRACT

@#Simulium triglobus Takaoka & Kuvangkadilok from Thailand, in the Simulium (Simulium) multistriatum species-group, is unique among species in the family Simuliidae in having the female terminalia with three spermathecae (rather than one spermatheca). This species was described from Nan province, northern Thailand based on larvae, pupae and females but its male has remained unknown. In this study, the male of S. triglobus is described for the first time based on adult males reared from pupae collected from the type locality. The most distinctive characteristic of the male of S. triglobus is the shape of the ventral plate, which is hexagonal when viewed ventrally. No other members of S. multistriatum species group known thus far have such a unique ventral plate. In addition, the number of upper-eye (large) facets and color patterns of the legs can be used to differentiate this species in the male from other members of the S. multistriatum species-group. Mitochondrial cytochrome c oxidase I sequences enabled association of adult male specimens of S. triglobus with previously known life stages. Phylogenetic analysis based on these sequences revealed that specimens of S. triglobus formed a strongly supported monophyletic clade, being genetically distinct from other members of S. multistriatum species-group in Thailand.

15.
Tropical Biomedicine ; : 78-85, 2022.
Article in English | WPRIM (Western Pacific) | ID: wpr-936407

ABSTRACT

@#The Simulium gombakense species-group, one of the 15 species-groups of the subgenus Gomphostilbia Enderlein, is small, being represented by only 12 species, all of which are distributed in the Oriental Region. It is characterized by the pupal gill composed of an inflated structure and eight or ten slender filaments. Among the 12 species, S. sachini Takaoka & Henry, and S. williei Takaoka & Thapa were originally described from two pupae, and one pupa and two larvae, respectively, from Darjeeling, India. In the present paper, the adult females and males of these species are described for the first time from specimens reared from pupae collected at the type locality. Simulium sachini is distinctive in the female by the claw with a medium-sized basal tooth, and in the male by the somewhat enlarged, spindleshaped hind basitarsus and ventral plate with its ventral margin much depressed medially, while S. williei is characterized by the small number of male upper-eye (large) facets in 12 vertical columns and 13 or 14 horizontal rows and ventral plate much produced posteroventrally. Taxonomic notes are given to separate these two species in the adult stage from their related species.

16.
Tropical Biomedicine ; : 231-238, 2022.
Article in English | WPRIM (Western Pacific) | ID: wpr-936931

ABSTRACT

@#Simulium (Gomphostilbia) ogatai (Rubtsov) from Japan, the only Palaearctic species in the S. ceylonicum species-group, is morphologically revised. Its female is described for the first time and its male and pupa are redescribed based on specimens from Gifu, Honshu. It is characterized in the female and male by the base of the radius with a tuft of yellow hairs, in the female by the head slightly wider than the thorax, 5.89 times as wide as the greatest width of the frons, and short sensory vesicle 0.21–0.24 times as long as the third palpal segment; in the male by the number of upper-eye (large) facets in 15 vertical columns and 16 horizontal rows, and hind basitarsus spindle-shaped, enlarged, 3.79 times as long as wide, and 0.83 and 1.00 times as wide as the greatest width of the hind tibia and femur, respectively; and in the pupa by the terminal hooks simple and cone-like, and the cocoon with an anterodorsal projection. Taxonomic notes for this species are given relevant to several related species in the Oriental Region, and its assignment to the S. ceylonicum species-group is confirmed.

17.
Parasit Vectors ; 14(1): 546, 2021 Oct 23.
Article in English | MEDLINE | ID: mdl-34688311

ABSTRACT

BACKGROUND: Despite high black fly densities in persisting onchocerciasis foci in Cameroon, no vector control has ever been carried out to complement Community-Directed Treatment with Ivermectin (CDTI). As a prelude to community-based vector control, this study explored knowledge/perception and attitude/practice (KAP) of populations of two first-line communities regarding onchocerciasis, black fly nuisance and bio-ecology. METHODS: A cross-sectional survey was conducted in two communities of the Bafia Health District, following a household-based interview approach using a structured questionnaire. KAP scores were calculated and categorised as good or poor based on the number of correct or positive responses. Associations between KAP and socio-demographic parameters were explored using logistic regression models. RESULTS: A total of 215 individuals aged 15-100 years were interviewed. Positive associations were observed between good knowledge/perception and age and the duration of residency in the community. Most respondents (91.6%) described having post-biting sequels (oedema, itching) and more than half (69.3%) admitted that black fly bites affect their productivity. Although 81.4% of the respondents stated that black fly densities are higher during the rainy season, only 10.7% of them knew that they breed in the river. Also, 59.5% of the interviewees stated that black flies bite not only outdoors but also indoors, and 78.6% of enrolees were ready to help to fight against black flies. Most of the respondents were well aware of onchocerciasis, even though the transmission mode and vector bio-ecology were not well known. CONCLUSION: This study revealed the need to implement community-based vector control to support CDTI in the fight against onchocerciasis and to reduce black fly nuisance.


Subject(s)
Health Knowledge, Attitudes, Practice , Onchocerciasis/psychology , Public Health , Simuliidae/parasitology , Adolescent , Adult , Aged , Aged, 80 and over , Animals , Antiparasitic Agents/therapeutic use , Cameroon/epidemiology , Cross-Sectional Studies , Endemic Diseases , Female , Humans , Ivermectin/therapeutic use , Logistic Models , Male , Middle Aged , Onchocerciasis/drug therapy , Onchocerciasis/epidemiology , Perception , Seasons , Surveys and Questionnaires , Young Adult
18.
Acta Trop ; 224: 106140, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34562429

ABSTRACT

Black flies (Diptera: Simuliidae) are known as vectors of disease agents in humans and livestock, with some species being vectors of Onchocerca volvulus, the filarial nematode that is the causative agent of human onchocerciasis. Nematode infections in adult female black flies have been reported from some areas in northern and western Thailand, but not from other regions of Thailand. In this study, wild-caught adult female black flies from the central region of Thailand were examined for infections with nematodes. Collections of adult females were carried out at Khlong Lan district, Kamphaeng Phet province, central Thailand. A molecular approach, based on the mitochondrial (cox1, 12S rRNA) and nuclear (18S rRNA) genes, was used to identify the species of nematodes recovered from the specimens collected. A total of 911 wild-caught adult black flies were collected. Simulium nigrogilvum was the most abundant species (n = 708), followed by S. doipuiense complex (n = 179), S. chamlongi (n = 11), S. umphangense (n = 10), S. chumpornense (n = 1), S. multistriatum species-group (n = 1), and S. maewongense (n = 1). Nematode infections were detected in nine specimens of S. nigrogilvum, of which two were positive for filarial worms (one worm each, infection rate 0.28%) and seven were positive for non-filarial nematodes (11 worms in total, infection rate 0.99%). The two filarial nematodes (third-stage larvae) were identified molecularly as Onchocerca species type I, while the 11 non-filarial nematodes were classified into ascaridoid (n = 2), tylenchid (n = 6) and mermithid (n = 3) nematodes. The results of this study demonstrated that adult female S. nigrogilvum were parasitized with diverse nematodes (filarial and non-filarial). Detection of the infective larvae of Onchocerca sp. type I in S. nigrogilvum confirms that occurrence of zoonotic onchocerciasis is highly possible in Thailand. Additional in-depth investigation of the morphology, life cycle and host-parasite relationship of nematodes that parasitized this black fly host is still needed.


Subject(s)
Bites and Stings , Onchocerciasis , Simuliidae , Animals , Female , Humans , Onchocerca/genetics , Onchocerciasis/epidemiology , Thailand
19.
Pathogens ; 10(8)2021 Jul 23.
Article in English | MEDLINE | ID: mdl-34451394

ABSTRACT

In 2006, vesicular stomatitis New Jersey virus (VSNJV) caused outbreaks in Wyoming (WY) horses and cattle after overwintering in 2004 and 2005. Within two weeks of the outbreak onset, 12,203 biting flies and 194 grasshoppers were collected near three equine-positive premises in Natrona County, WY. Insects were identified to the species level and tested by RT-qPCR for VSNJV polymerase (L) and phosphoprotein (P) gene RNA. Collected dipterans known to be competent for VSV transmission included Simulium black flies and Culicoides biting midges. VSNJV L and P RNA was detected in two pools of female Simulium bivittatum and subjected to partial genome sequencing. Phylogenetic analysis based on the hypervariable region of the P gene from black flies showed 100% identity to the isolate obtained from the index horse case on the same premises. This is the first report of VSNJV in S. bivittatum in WY and the first field evidence of possible VSV maintenance in black fly populations during an outbreak.

20.
Acta Trop ; 221: 106030, 2021 Sep.
Article in English | MEDLINE | ID: mdl-34217727

ABSTRACT

A new species of black fly from rock fields of southeaster Brazil, Simulium maiaherzogae sp. nov., is described based on morphological features of larval, pupal and adult specimens. Morphological features of this new species were compared with members of Simulium (Trichodagmia) Enderlein 1934, showing a high similarity with S. scutistriatum Lutz 1909 and S. itajara Nascimento, et al. 2020. However, features of the male and female scutum and genitalia, pupal tubercles disposition, pupal gills, larval cephalic appendages, larval gill histoblast, numbers of posterior proleg hooks and rectal papillae lobules, allow to differentiate S. maiaherzogae sp. nov. Moreover, a more detailed analysis using Scanning Electron Microscopy (SEM) showed significant differences and numerical variations in meristic data between the new species and S. scutistriatum. The known distribution of this new species is restricted to the Rio do Salto sub-basin, headland of the Middle Paraíba do Sul River, near the Ibitipoca State Park, a region recognised for its biodiversity richness, but with rare simuliids records.


Subject(s)
Simuliidae , Animals , Biodiversity , Brazil , Female , Larva , Male , Pupa , Simuliidae/anatomy & histology , Simuliidae/classification
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