Abadi M Mashlawi1,2, Ashwaq M Al-Nazawi3, Elsiddig M Noureldin4, Hussain Alqahtani5,6, Jazem A Mahyoub7, Jassada Saingamsook8, Mustapha Debboun9, Martha Kaddumukasa10, Hesham M Al-Mekhlafi11,12, Catherine Walton13. 1. Department of Earth and Environmental Sciences, Faculty of Science and Engineering, University of Manchester, Manchester, M13 9PL, UK. abadimashlawi@gmail.com. 2. Department of Biology, Faculty of Science, Jazan University, Jazan, 45142, Saudi Arabia. abadimashlawi@gmail.com. 3. Preventive Medicine Department, Public Health Directorate, Ministry of Health, Jeddah, Saudi Arabia. 4. Saudi Center for Disease Control & Prevention, Ministry of Health, Jazan, Saudi Arabia. 5. Department of Earth and Environmental Sciences, Faculty of Science and Engineering, University of Manchester, Manchester, M13 9PL, UK. 6. Department of Biology, Faculty of Science, University of Tabuk, Tabuk, Saudi Arabia. 7. Department of Biology Sciences, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia. 8. Center of Insect Vector Study, Department of Parasitology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand. 9. Delta Mosquito and Vector Control District, Visalia, CA, USA. 10. Department of Biological Sciences, Faculty of Science, Kyambogo University, P.O. Box 1, Kampala, Uganda. 11. Department of Epidemiology, Faculty of Public Health and Tropical Medicine, Jazan University, Jazan, 45142, Saudi Arabia. 12. Department of Parasitology, Faculty of Medicine and Health Sciences, Sana'a University, P.O. Box 1247, Sana'a, Yemen. 13. Department of Earth and Environmental Sciences, Faculty of Science and Engineering, University of Manchester, Manchester, M13 9PL, UK. Catherine.Walton@manchester.ac.uk.
Abstract
BACKGROUND: The Aedes aegypti mosquito is the primary vector for dengue, chikungunya, yellow fever and Zika viruses worldwide. The first record of Ae. aegypti in southwestern Saudi Arabia was in 1956. However, the first outbreak and cases of dengue fever were reported in 1994, and cases have increased in recent years. Vector control for Ae. aegypti mainly uses pyrethroid insecticides in outdoor and indoor space spraying. The constant use of pyrethroids has exerted intense selection pressure for developing target-site mutations in the voltage-gated sodium channel (vgsc) gene in Ae. Aegypti against pyrethroids-mutations that have led to knockdown resistance (kdr). METHODS: Aedes aegypti field populations from five regions (Jazan, Sahil, Makkah, Jeddah and Madinah) of southwestern Saudi Arabia were genotyped for known kdr mutations in domains IIS6 and IIIS6 of the vgsc gene using polymerase chain reaction (PCR) amplification and sequencing. We estimated the frequency of kdr mutations and genotypes from Saudi Arabia as well as from other countries, Thailand, Myanmar (Southeast Asia) and Uganda (East Africa). We constructed haplotype networks to infer the evolutionary relationships of these gene regions. RESULTS: The three known kdr mutations, S989P, V1016G (IIS6) and F1534C (IIIS6), were detected in all five regions of Saudi Arabia. Interestingly, the triple homozygous wild genotype was reported for the first time in two individuals from the highlands of the Jazan region and one from the Al-Quoz, Sahil region. Overall, nine genotypes comprising four haplotypes were observed in southwestern Saudi Arabia. The median-joining haplotype networks of eight populations from Saudi Arabia, Southeast Asia and East Africa for both the IIS6 and IIIS6 domains revealed that haplotype diversity was highest in Uganda and in the Jazan and Sahil regions of Saudi Arabia, whereas haplotype diversity was low in the Jeddah, Makkah and Madinah regions. Median-joining haplotype networks of both domains indicated selection acting on the kdr-mutation containing haplotypes in Saudi Arabia. CONCLUSIONS: The presence of wild type haplotypes without any of the three kdr mutations, i.e. that are fully susceptible, in Saudi Arabia indicates that further consideration should be given to insecticide resistance management strategies that could restore pyrethroid sensitivity to the populations of Ae. aegypti in Saudi Arabia as part of an integrative vector control strategy.
BACKGROUND: The Aedes aegypti mosquito is the primary vector for dengue, chikungunya, yellow fever and Zika viruses worldwide. The first record of Ae. aegypti in southwestern Saudi Arabia was in 1956. However, the first outbreak and cases of dengue fever were reported in 1994, and cases have increased in recent years. Vector control for Ae. aegypti mainly uses pyrethroid insecticides in outdoor and indoor space spraying. The constant use of pyrethroids has exerted intense selection pressure for developing target-site mutations in the voltage-gated sodium channel (vgsc) gene in Ae. Aegypti against pyrethroids-mutations that have led to knockdown resistance (kdr). METHODS: Aedes aegypti field populations from five regions (Jazan, Sahil, Makkah, Jeddah and Madinah) of southwestern Saudi Arabia were genotyped for known kdr mutations in domains IIS6 and IIIS6 of the vgsc gene using polymerase chain reaction (PCR) amplification and sequencing. We estimated the frequency of kdr mutations and genotypes from Saudi Arabia as well as from other countries, Thailand, Myanmar (Southeast Asia) and Uganda (East Africa). We constructed haplotype networks to infer the evolutionary relationships of these gene regions. RESULTS: The three known kdr mutations, S989P, V1016G (IIS6) and F1534C (IIIS6), were detected in all five regions of Saudi Arabia. Interestingly, the triple homozygous wild genotype was reported for the first time in two individuals from the highlands of the Jazan region and one from the Al-Quoz, Sahil region. Overall, nine genotypes comprising four haplotypes were observed in southwestern Saudi Arabia. The median-joining haplotype networks of eight populations from Saudi Arabia, Southeast Asia and East Africa for both the IIS6 and IIIS6 domains revealed that haplotype diversity was highest in Uganda and in the Jazan and Sahil regions of Saudi Arabia, whereas haplotype diversity was low in the Jeddah, Makkah and Madinah regions. Median-joining haplotype networks of both domains indicated selection acting on the kdr-mutation containing haplotypes in Saudi Arabia. CONCLUSIONS: The presence of wild type haplotypes without any of the three kdr mutations, i.e. that are fully susceptible, in Saudi Arabia indicates that further consideration should be given to insecticide resistance management strategies that could restore pyrethroid sensitivity to the populations of Ae. aegypti in Saudi Arabia as part of an integrative vector control strategy.
Authors: Rajaa Al-Raddadi; Osama Alwafi; Omima Shabouni; Naeema Akbar; Mohammed Alkhalawi; Adel Ibrahim; Raheela Hussain; Mohammed Alzahrani; Mohammed Al Helal; Abdullah Assiri Journal: Acta Trop Date: 2018-09-20 Impact factor: 3.112
Authors: John M Humphrey; Natalie B Cleton; Chantal B E M Reusken; Marshall J Glesby; Marion P G Koopmans; Laith J Abu-Raddad Journal: PLoS Negl Trop Dis Date: 2016-12-07
Authors: Ashwaq M Al Nazawi; Jabir Aqili; Mohammed Alzahrani; Philip J McCall; David Weetman Journal: Parasit Vectors Date: 2017-03-27 Impact factor: 3.876