Target Site Insensitivity Detection in Deltamethrin Resistant Culex pipiens Complex in Iran.

BACKGROUND: Some mosquito species which belong to the Culex. pipiens complex are primary vectors for West Nile virus, Sindbis, Dirofilaria immitis, and many arboviruses. Knockdown resistance (kdr) mutations in the voltage-gated sodium channel (VGSC) gene of Cx. pipiens that is inherited, is one of the important threats for the efficacy of pyrethroids insecticides. Knockdown resistance (kdr) mutation, L1014F, is a well-defined mechanism of resistance to pyrethroids and DDT in many insect species. The aim of study was to determine the mechanisms of Insecticide resistance in this species. METHODS: Specimens of Cx. pipiens, the major vector of West Nile virus, were obtained in Tehran, Iran by collecting larvae from polluted wastewater in Qarchak of Tehran. In 2016 Insecticide susceptibility tests were performed according to WHO methods with deltamethrin 0.05%. We focused on determination of this point mutation in the VGSC gene of Cx. pipiens by Real-time PCR. RESULTS: Our results revealed high levels of resistance to deltamethrin 0.05%. The lethal times i.e. LT50 and LT90 for deltamethrin were 2.1530 and 8.5117 h respectively. The result of Real-time PCR confirmed the presence of resistant genotype in all the members of tested population. This study is the first report on kdr genotyping of Cx. pipiens from Tehran and our results on the VGSC gene in position L1014F confirmed the TTA to TTT nucleotide change. CONCLUSION: This finding will provide a clue for management of insecticide resistance in mosquito which are vectors of arboviruses and decision for replacement of novel approach for vector control.

Biodiversity of Mosquitoes (Diptera: Culicidae) with Emphasis on Potential Arbovirus Vectors in East Azerbaijan Province, Northwestern Iran.

BACKGROUND: The abundance, diversity, distribution and ecology of mosquitoes (Diptera: Culicidae), especially arbovirus vectors are important indices for arthropod-borne diseases control. METHODS: Larvae and adult mosquitoes were collected using the standard methods from different habitats in nine localities of three counties in the East Azerbaijan Province, Northwestern Iran during June to October 2017. In addition, species richness (R), Simpson's diversity index (D), Shannon-Wiener index (H') and evenness (E) as measures of diversity, were calculated. RESULTS: Overall, 1401 mosquito specimens including 1015 adults and 386 larvae were collected in the study area. The properties of geographical larval habitats were recorded. Four genera along with 10 species were collected and identified, including Anopheles hyrcanus, An. maculipennis s.l., An. superpictus s.l., Aedes caspius, Ae. vexans, Culex pipiens, Cx. theileri, Cx. perexiguus, Culiseta longiareolata and Cs. subochrea. Among the three counties, Ahar region presented the highest species richness (R: 1.5) and diversity values (D: 0.79, H': 1.74, E: 0.73). CONCLUSION: This study provides important information on the diversity, distribution and ecology of ten mosquito species in the region. This information leads to a better understanding of mosquito population dynamics in relation to vector control measures.

Baseline Susceptibility of Culiseta longiareolata (Diptera: Culicidae) to Different Imagicides, in Eastern Azerbaijan, Iran.

BACKGROUND: Culiseta longiareolata is an important vector for many human diseases such as brucellosis, avian influenza and West Nile encephalitis. It is likely an intermediate host of avian Plasmodium that can transmit Malta fever. The aim of this study was to determine the susceptibility level of Cs. longiareolata to different classes of imagicides which are recommended by World Health Organization . METHODS: Larval stages of the Cs. longiareolata were collected from their natural habitats in Marand County at East Azerbaijan Province, northwestern of Iran in 2017. Adult susceptibility test were carried out with using impregnated papers to insecticides including DDT 4%, Cyfluthrin 0.15%, Deltamethrin 0.05%, Propoxur 0.1% and Fenitrothion 1% by standard test kits. RESULTS: Results showed that Cs. longiareolata adult is more susceptible to pyrethroid and carbamate insecticides. Among tested insecticides, Cyfluthrin was the most toxic against Cs. longiareolata with LT50 value of 11.53 minutes and Fenitrothion had the least toxic effect (LT50: 63.39 min). CONCLUSIONS: This study provided a guideline for monitoring and evaluation of insecticide susceptibility tests against Cs. longiareolata mosquitoes for further decision making.

Phylogenetic analysis of the oriental-Palearctic-Afrotropical members of Anopheles (Culicidae: Diptera) based on nuclear rDNA and mitochondrial DNA characteristics.

The phylogenetic relationships of Anopheles spp. at the junction of Oriental, Palearctic, and Afrotropical regions in the Iranian plateau were investigated using molecular markers. A 711-bp mitochondrial DNA cytochrome oxidase C subunit I (COI) fragment and the entire second internal transcribed spacer (ITS2) region (286-576 bp) of the nuclear ribosomal DNA (rDNA-ITS2) were sequenced from 14 and 28 taxa, respectively. The analyses included 12 species within Anopheles and 4 within the Myzorhynchus Series of the subgenus Anopheles, 8 within Neocellia, 6 within Myzomyia, 3 within Paramyzomyia, and 1 within the Pyretophorus Series of the subgenus Cellia. The congruent tree topologies of both molecular markers strongly supported monophyly of subgenera Anopheles and Cellia. Phylogenetic trees constructed on the basis of ITS2 sequences could accurately categorize all of the series according to the classical taxonomy but could not distinguish Pyretophorus (Anopheles subpictus) from Paramyzomyia Series. Although sequence data of the COI region were available for only 14 species, the inferred trees revealed good classification among the series but could not show the monophyletic relationship of Cellia spp. Except for a few cases, the tree inferred from ITS2 sequences revealed the best classification for the species studied. The molecular data could significantly improve our understanding of the phylogenetic position of the taxa.

Species diversity and geographic distribution of hard ticks (Acari: Ixodoidea: Ixodidae) infesting domestic ruminants, in Qazvin Province, Iran.

This report presents the results of the first faunistic study of hard ticks in Qazvin province of Iran. The primary objective was to determine the species diversity and geographic distribution of hard ticks that parasitize domestic ruminants. Information about the abiotic preferences of these species has been provided. A total of 286 cattle, 1,053 goats, and 2,050 sheep were examined in 13 villages in 28 flocks distributed throughout the studied areas. Total direct body collections of ticks were made from each domestic ruminant. A total of 228 Ixodid specimens belonging to nine species in three different genera were recorded in the areas, including Boophilus annulatus (Say, 1821), Hyalomma anatolicum Koch, 1844, Hyalomma asiaticum (Schulze and Schlettke, 1929), Hyalomma detritum Schulze, 1919, Hyalomma dromedarii Koch, 1844, Hyalomma marginatum Koch 1844, Hyalomma schulzei Olenev, 1931, Rhipicephalus bursa Canestrini and Fanz, 1878 and Rhipicephalus sanguineus (Latreille, 1806). The most abundant species on sheep was R. sanguineus (46.92%), while B. annulatus (6.6%) found only on cattle. A finding of great significance was that R. sanguineus, the main vector of babesiosis, is firmly established throughout the counties. A further objective of the study was to compare the abundance of the major tick species on domestic ruminants. This was carried out at 19 sampling sites. The highest number of ticks was collected in July-August during the hot season.