First report of Culex (Lophoceraomyia) cinctellus in Sri Lanka: Evidence from morphological and molecular analysis

Abstract

Objective: To confirm the presence of Culex (Cx.) (Lophoceraomyia) cinctellus in Sri Lanka using morphological and molecular evidence.

Methods From October 2019 to April 2020, mosquito surveillance was conducted fort-nightly in the Banduragoda Public Health Inspector area. Larvae were collected using standard siphoning methods, while adults were sampled using Cattle Baited Trap, Gravid Traps, Light Traps, Bird-Baited Traps, Dog Baited Traps, and diurnal human landing collections. Specimens were transported to the Entomology Laboratory at the Medical Research Institute for identification. Morphological identification was performed using standard taxonomic keys. Molecular confirmation was achieved through DNA sequencing of mosquito head and thoracic regions, followed by sequence analysis using NCBI BLAST and Geneious software (version 7.1.3).

Results: Adults of Cx. cinctellus were identified in Bird-Baited Traps and human bait collections. Unique morphological characteristics, including well-developed pulvilli, wing vein 1A ending before the apex of cross vein mcu, basal transverse pale bands on abdominal terga, and two labial basal setae on the proboscis, confirmed species identity. Morphometric measurements included mean thoracic length (0.58±0.02) mm, thoracic width (0.63±0.02) mm, abdominal length (2.15±0.03) mm, abdominal width (0.61±0.01) mm, and wing length (2.91±0.02) mm. Molecular analysis corroborated the morphological identification, affirming the species as Cx. cinctellus. COI sequences of the collected specimen (452 bp) were confirmed as Cx. cinctellus for sequence identity by BLAST and BOLD analysis. These sequences were subsequently deposited in GenBank under the accession number OR225623.1.

Conclusions: This study documents the first occurrence of Cx. cinctellus in Sri Lanka, highlighting the need to enhance entomological surveillance to monitor its dispersal and population dynamics.

Keywords

Culex cinctellus / Entomological surveillance / Morphological identification / Molecular confirmation / Mosquito checklist Sri Lanka

Conflict of interest statement

The authors declare that they have no competing interests.

Availability of data and materials

The datasets supporting the conclusions of this article are included within the article. The generated sequence is available in the GenBank database under the accession number OR225623.1.

Acknowledgements

The authors are grateful to the residents of the study areas and the staff of the Medical Research Institute, Sri Lanka for supporting the entomological surveillance activities.

Funding

The authors received no extramural funding for the study.

Authors’ contributions

PR, GK, NJ and WR: Conducted field surveillance and laboratory experiments, supported data analysis; LU: Wrote the manuscript and supervised the study; TR: Designed and supervised the research, wrote the manuscript; TK: Performed the molecular analysis and reviewed the manuscript. All authors read and approved the final manuscript.

Publisher’s note

The Publisher of the Journal remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

References

[1] Musso D, Rodriguez-Morales AJ, Levi JE, Cao-Lormeau VM, Gubler DJ. Unexpected outbreaks of arbovirus infections: Lessons learned from the Pacific and tropical America. Lancet Infect Dis 2018; 18(11): e355-e361.

[2] Gunathilaka NA. Annotated checklist and review of the mosquito species (Diptera: Culicidae) in Sri Lanka. J Insect Biodivers 2018; 7(3): 38-50.

[3] Nasir SI, Amarasekara S, Wickremasinghe R, Fernando D, Udagama P. Prevention of re-establishment of malaria: Historical perspective and future prospects. Malar J 2020; 19: 1-6.

[4] Foster WA, Walker ED. Mosquitoes (Culicidae). In: Medical and veterinary entomology. Cambridge, US: Academic Press; 2019, p. 261-325.

[5] Colless DH. The genus Culex, subgenus Lophoceraomyia, in Malaya (Diptera: Culicidae). J Med Entomol 1965; 2(3): 261-307.

[6] Han S, Miot EF, Liao Y, Somboon P, Harbach RE, Sze-To KM, et al. Updated checklist with new records and molecular data for the mosquitoes (Diptera: Culicidae) of Hong Kong. J Med Entomol 2024; 125: 1-13.

[7] Withanage GP, Viswakula SD, Nilmini Silva Gunawardena YI, Hapugoda MD. A forecasting model for dengue incidence in the District of Gampaha, Sri Lanka. Parasit Vectors 2018; 11: 262.

[8] Panthusiri P. Illustrated keys to the mosquitoes of Thailand i1. Genera Culex and Lutzia. Southeast Asian J Trop Med Public Health 2005; 36: 2.

[9] Qiagen. DNeasy blood and tissue handbook;2011. [Online]. Available from: http://www.bea.ki.se/documents/EN-DNeasy%20handbook.pdf. [Accessed on 27 March 2020].

[10] Chan A, Chiang LP, Hapuarachchi HC, Tan CH, Pang SC, Lee R, et al. DNA barcoding: Complementing morphological identification of mosquito species in Singapore. Parasit Vectors 2014; 7: 569.

[11] Zhang L, Madden TL. PowerBLAST: A new network BLAST application for interactive or automated sequence analysis and annotation. Genome Methods 1997; 7: 649-656.

[12] Tamura K, Stecher G, Kumar S, MEGA11: Molecular evolutionary genetics analysis version 11. Molbiol Evol 2021; 38(7): 3022-3027.

[13] Green EE. Mosquitoes and malaria. Circul Royal Botan Gardens Ceylon 1 1901; 25: 345-368.

[14] Theobald FV. A monograph of the Culicidae or mosquitoes. Iillus London 1901; 1: 424.

[15] Christophers SR. The fauna of British India, including Ceylon and Burma. Tribe Anophelini 1933; 48: 371-372.

[16] Barraud PJ. Family Culicidae. Tribes Megarhinini and Culicini. The Fauna of British India including Ceylon and Burma. Diptera 1934; 5: 463.

[17] Carter HF. Ceylon mosquitoes: Lists of species and names of mosquitoes recorded from Ceylon. Ceylon J Sci 1950; 24(2): 85-115.

[18] Chow CY, Thevasagayam ES, Tharumarajah K. Insects of public health im-portance in Ceylon. Revista Ecuatoriana de Entomologia y Parasitologia 1954; 2(1-2): 115-119.

[19] Jayasekera N, Chelliah RV. An annotated checklist of mosquitoes of Sri Lanka. MAB-UNESCO-Man and the Biosphere National Committee for Sri Lanka 1981; 8: 1-16.

[20] Amerasinghe FP. A catalog of the mosquitoes in Sri Lanka.Colombo: Natural Resources, Energy and Science Authority of Sri Lanka; 1991, p. 1-23.

[21] Gunathilaka N. Annotated checklist and review of the mosquito species (Diptera: Culicidae) in Sri Lanka. J Insect Biodiv 2018; 7(3): 1-14.

[22] Cywinska A, Hunter FF, Hebert PD. Identifying Canadian mosquito species through DNA barcodes. Med Veterin Entomol 2006; 20(4): 413-424.

[23] Hebert PD, Cywinska A, Ball SL, DeWaard JR. Biological identifications through DNA barcodes. Proceed Royal Society London. Series B: Biol Sci 2003; 270(1512): 313-321.

[24] Hillis DM, Huelsenbeck JP, Cunningham CW. Application and accuracy of molecular phylogenies. Science 1994; 264(5159): 671-677.

[25] Lhaosudto S, Ngoen-Klan R, Meunworn V, Kongmee M, Hii J, Chareonviriyaphap T. Comparison of different spectral ranges of UV-LED lighting for outdoor mosquito trapping in forested area in Thailand. J Med Entomol 2024; 61(6): 1510-1518.

[26] Rao RU, Nagodavithana KC, Samarasekera SD, Wijegunawardana AD, Premakumara WD, Perera SN, et al. A comprehensive assessment of lymphatic filariasis in Sri Lanka six years after cessation of mass drug administration. PLoS Negl Trop Dis 2014; 8(11): e3281.

[27] Amuzu H, Wilson MD, Boakye DA. Studies of Anopheles gambiae (Diptera: Culicidae) exhibiting different vectorial capacities in lymphatic filariasis transmission in the Gomoa district, Ghana. Parasit Vectors 2010; 3: 1-6.

[28] Schorderet-Weber S, Noack S, Selzer PM, Kaminsky R. Blocking transmis-sion of vector-borne diseases. Drug Discov Against Moving Targets 2018; 30: 43-94.

[29] Chandrasena N, Premaratna R, Gunaratna IE, de Silva NR. Morbidity man-agement and disability prevention for lymphatic filariasis in Sri Lanka: Current status and future prospects. PLoS Negl Trop Dis 2018; 12(5): e0006472.