Molecular characterization of black flies (Diptera: Simuliidae) in areas with pest outbreaks and simuliotoxicosis in Northeast Anatolia Region, Turkey

Surveillance along the Rio Grande during the 2020 Vesicular Stomatitis Outbreak Reveals Spatio-Temporal Dynamics of and Viral RNA Detection in Black Flies

Vesicular stomatitis virus (VSV) emerges periodically from its focus of endemic transmission in southern Mexico to cause epizootics in livestock in the US. The ecology of VSV involves a diverse, but largely undefined, repertoire of potential reservoir hosts and invertebrate vectors. As part of a larger program to decipher VSV transmission, we conducted a study of the spatiotemporal dynamics of Simulium black flies, a known vector of VSV, along the Rio Grande in southern New Mexico, USA from March to December 2020. Serendipitously, the index case of VSV-Indiana (VSIV) in the USA in 2020 occurred at a central point of our study. Black flies appeared soon after the release of the Rio Grande’s water from an upstream dam in March 2020. Two-month and one-year lagged precipitation, maximum temperature, and vegetation greenness, measured as Normalized Difference Vegetation Index (NDVI), were associated with increased black fly abundance. We detected VSIV RNA in 11 pools comprising five black fly species using rRT-PCR; five pools yielded a VSIV sequence. To our knowledge, this is the first detection of VSV in the western US from vectors that were not collected on premises with infected domestic animals.

Chromosomal and Molecular Diversity in the Simulium ornatum Group (Diptera: Simuliidae) in the Western Tian Shan Range of Central Asia

By any measure, such as abundance, species diversity or geographic range, the Simulium ornatum species group is one of the most successful Palearctic taxa of black flies. To explore potential diversity in this group in the Tian Shan range of Central Asia, we focused on Kyrgyzstan, in which three nominal morphospecies have been recorded. Among our samples, we morphologically identified S. mesasiaticum Rubtsov and a second possible species tentatively identified as S. ferganicum Rubtsov. By analyzing banding patterns of the larval polytene chromosomes, we discovered two fixed inversions, two sex-linked rearrangements, and 19 autosomal rearrangements, including supernumerary B chromosomes. The chromosomal data indicate minimal diversity of only one or two species across the surveyed area of nearly 50,000 km². Mitochondrial DNA (CO1) sequences fell into three distinct clusters, possibly representing separate species. The chromosomal, molecular, and morphological data indicate that Kyrgyz populations are unique within the S. ornatum group, but the data sets are not entirely congruent. Thus, reconciling data sets and assigning existing names is tentative. Simulium mesasiaticum is linked with undifferentiated sex chromosomes, one of the three CO1 clades, and higher elevations, whereas S. ferganicum is tenuously associated with differentiated sex chromosomes, a separate CO1 clade, and lower elevations. These associations leave one Kyrgyz larva, which is in a third CO1 clade, unlinked to a formal species name. Our analyses also indicate that S. ornatum Meigen sensu stricto, contrary to previous reports, does not occur in Kyrgyzstan and should be deleted from the country's faunal list.

Prevalence and genetic diversity of avian haemosporidian parasites at an intersection point of bird migration routes: Sultan Marshes National Park, Turkey

Avian haemosporidians (Haemosporida) represent a globally distributed, species-rich multiparasite-multihost host-parasite system. Each year, many of these parasite lineages are carried between temperate and tropical regions by migratory birds. While several factors can limit the transmission of avian haemosporidians to new areas, recent studies have shown that some abundant parasites can sometimes disperse and be transmitted in new areas to become emerging infectious diseases. In this study, we investigated the prevalence and diversity of avian haemosporidian parasites in Sultan Marshes National Park (SMNP), a major stopover site in the eastern Mediterranean flyway, and we evaluated the potential for avian haemosporidians in SMNP to be transmitted to areas outside of their known distributions. We sampled a total of 565 migratory and resident birds belonging to 39 species and 23 families. We applied both molecular and microscopic methods to detect and identify avian haemosporidian infections and also quantified the frequency of potential abortive infections. We identified a total of 52 different mitochondrial cytochrome b (cyt b) parasite lineages belonging to the genera Plasmodium (N = 12), Haemoproteus (N = 31), and Leucocytozoon (N = 9) in 193 (34.2%) infected birds. Ten of the lineages were reported for the first time. Our findings show that numerous parasite lineages are actively transmitted among resident bird species of SMNP. Our findings also revealed new parasite-host interactions while considering the role of possible abortive infections. The relatively high frequency of presumed abortive infections suggests that analyses of datasets generated only by PCR-based methods should be interpreted with caution. We also compared the prevalence and distribution of avian haemosporidian infections in both resident and migratory bird species and showed that haemosporidian prevalence was related to bird migratory behavior. The results of this study contribute to a better understanding of the ecological and genetic adaptations associated with changes in transmission areas of avian haemosporidian parasites.

New records and DNA barcoding of deer flies, Chrysops (Diptera: Tabanidae) in Thailand

Chrysops spp. or deer flies (Diptera: Tabanidae) are hematophagous flies of medical and veterinary importance and some species are important vectors of Trypanosoma evansi, the causative agent of surra in Thailand. However, data regarding deer fly species and their molecular identification are limited. Accurate species identification will indicate the appropriate control measures. In this study, an entomological survey of deer flies from different sites in Thailand between May 2018 and June 2019 were conducted. In addition, mitochondrial cytochrome oxidase subunit I (COI) barcoding region was used for species identification. A total of 82 females were collected and 6 species were identified. Of these, three species are new records for Thailand: C. designatus, C. fuscomarginalis and C. vanderwulpi bringing the species total found in Thailand to nine. The COI sequences revealed an intraspecific divergence of 0.0%-2.65% and an interspecific divergence of 7.03%-13.47%. Phylogenetic analysis showed that all deer fly species were clearly separated into distinct clusters according to morphologically identified species. These results indicated that COI barcodes were capable in discriminating between deer fly species on the basis of the barcoding gap and phylogenetic analysis. Therefore, DNA barcoding is a valuable tool for species identification of deer flies in Thailand.

Molecular Identification and Geometric Morphometric Analysis of Haematobosca aberrans (Diptera: Muscidae)

The genus Haematobosca Bezzi, 1907 (Diptera: Muscidae) contains haematophagous flies of veterinary importance. A new fly species of this genus was recognised from northern Thailand based on morphological characters and described as Haematobosca aberrans Pont, Duvallet & Changbunjong, 2020. In the present study, the mitochondrial cytochrome c oxidase I (COI) gene was used to confirm the morphological identification of H. aberrans. In addition, landmark-based geometric morphometrics was used to determine sexual dimorphism. The molecular analysis was conducted with 10 COI sequences. The results showed that all sequences were 100% identical. The sequence was not highly similar to reference sequences from GenBank and did not match any identified species from Barcode of Life Data Systems (BOLD). Phylogenetic analysis clearly differentiated this species from other species within the subfamily Stomoxyinae. For geometric morphometric analysis, a total of 16 wing pictures were analysed using the landmark-based approach. The results showed significant differences in wing shape between males and females, with a cross-validated classification score of 100%. The allometric analysis showed that wing shape has no correlation with size. Therefore, the COI gene is effective in species identification of H. aberrans, and geometric morphometrics is also effective in determining sexual dimorphism.