Back to Search Start Over

Spatiotemporal distribution and bionomics of Anopheles stephensi in different eco-epidemiological settings in Ethiopia

Authors :
Temesgen Ashine
Adane Eyasu
Yehenew Asmamaw
Eba Simma
Endalew Zemene
Adrienne Epstein
Rebecca Brown
Nigatu Negash
Abena Kochora
Alison M. Reynolds
Mikiyas Gebremichael Bulto
Temesgen Tafesse
Alemayehu Dagne
Biniyam Lukus
Endashaw Esayas
Sinknesh Wolde Behaksra
Kidist Woldekidan
Fikregabrail Aberra Kassa
Jimma Dinsa Deressa
Muluken Assefa
Dereje Dillu
Gudissa Assefa
Hiwot Solomon
Ahmed Zeynudin
Fekadu Massebo
Luigi Sedda
Martin James Donnelly
Anne L. Wilson
David Weetman
Endalamaw Gadisa
Delenasaw Yewhalaw
Source :
Parasites & Vectors, Vol 17, Iss 1, Pp 1-18 (2024)
Publication Year :
2024
Publisher :
BMC, 2024.

Abstract

Abstract Background Malaria is a major public health concern in Ethiopia, and its incidence could worsen with the spread of the invasive mosquito species Anopheles stephensi in the country. This study aimed to provide updates on the distribution of An. stephensi and likely household exposure in Ethiopia. Methods Entomological surveillance was performed in 26 urban settings in Ethiopia from 2021 to 2023. A kilometer-by-kilometer quadrant was established per town, and approximately 20 structures per quadrant were surveyed every 3 months. Additional extensive sampling was conducted in 50 randomly selected structures in four urban centers in 2022 and 2023 to assess households’ exposure to An. stephensi. Prokopack aspirators and CDC light traps were used to collect adult mosquitoes, and standard dippers were used to collect immature stages. The collected mosquitoes were identified to species level by morphological keys and molecular methods. PCR assays were used to assess Plasmodium infection and mosquito blood meal source. Results Catches of adult An. stephensi were generally low (mean: 0.15 per trap), with eight positive sites among the 26 surveyed. This mosquito species was reported for the first time in Assosa, western Ethiopia. Anopheles stephensi was the predominant species in four of the eight positive sites, accounting for 75–100% relative abundance of the adult Anopheles catches. Household-level exposure, defined as the percentage of households with a peridomestic presence of An. stephensi, ranged from 18% in Metehara to 30% in Danan. Anopheles arabiensis was the predominant species in 20 of the 26 sites, accounting for 42.9–100% of the Anopheles catches. Bovine blood index, ovine blood index and human blood index values were 69.2%, 32.3% and 24.6%, respectively, for An. stephensi, and 65.4%, 46.7% and 35.8%, respectively, for An. arabiensis. None of the 197 An. stephensi mosquitoes assayed tested positive for Plasmodium sporozoite, while of the 1434 An. arabiensis mosquitoes assayed, 62 were positive for Plasmodium (10 for P. falciparum and 52 for P. vivax). Conclusions This study shows that the geographical range of An. stephensi has expanded to western Ethiopia. Strongly zoophagic behavior coupled with low adult catches might explain the absence of Plasmodium infection. The level of household exposure to An. stephensi in this study varied across positive sites. Further research is needed to better understand the bionomics and contribution of An. stephensi to malaria transmission. Graphical Abstract

Details

Language :
English
ISSN :
17563305
Volume :
17
Issue :
1
Database :
Directory of Open Access Journals
Journal :
Parasites & Vectors
Publication Type :
Academic Journal
Accession number :
edsdoj.019c046e68b44fe5b307fbdcf9bd1cad
Document Type :
article
Full Text :
https://doi.org/10.1186/s13071-024-06243-3