1
|
Cross DE, Healey AJE, McKeown NJ, Thomas CJ, Macarie NA, Siaziyu V, Singini D, Liywalii F, Sakala J, Silumesii A, Shaw PW. Temporally consistent predominance and distribution of secondary malaria vectors in the Anopheles community of the upper Zambezi floodplain. Sci Rep 2022; 12:240. [PMID: 34997149 PMCID: PMC8742069 DOI: 10.1038/s41598-021-04314-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 12/10/2021] [Indexed: 11/09/2022] Open
Abstract
Regional optimisation of malaria vector control approaches requires detailed understanding both of the species composition of Anopheles mosquito communities, and how they vary over spatial and temporal scales. Knowledge of vector community dynamics is particularly important in settings where ecohydrological conditions fluctuate seasonally and inter-annually, such as the Barotse floodplain of the upper Zambezi river. DNA barcoding of anopheline larvae sampled in the 2019 wet season revealed the predominance of secondary vector species, with An. coustani comprising > 80% of sampled larvae and distributed ubiquitously across all ecological zones. Extensive larval sampling, plus a smaller survey of adult mosquitoes, identified geographic clusters of primary vectors, but represented only 2% of anopheline larvae. Comparisons with larval surveys in 2017/2018 and a contemporaneous independent 5-year dataset from adult trapping corroborated this paucity of primary vectors across years, and the consistent numerical dominance of An. coustani and other secondary vectors in both dry and wet seasons, despite substantial inter-annual variation in hydrological conditions. This marked temporal consistency of spatial distribution and anopheline community composition presents an opportunity to target predominant secondary vectors outdoors. Larval source management should be considered, alongside prevalent indoor-based approaches, amongst a diversification of vector control approaches to more effectively combat residual malaria transmission.
Collapse
Affiliation(s)
- Dónall Eoin Cross
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, SY23 3FG, UK
| | - Amy J E Healey
- Lincoln Centre for Water and Planetary Health, College of Science, University of Lincoln, Brayford Pool Campus, Lincoln, LN6 7TS, UK
| | - Niall J McKeown
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, SY23 3FG, UK
| | - Christopher James Thomas
- Lincoln Centre for Water and Planetary Health, College of Science, University of Lincoln, Brayford Pool Campus, Lincoln, LN6 7TS, UK.
| | - Nicolae Adrian Macarie
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, SY23 3FG, UK
| | - Vincent Siaziyu
- Limulunga District Health Office, P.O. Box 910022, Mongu, Zambia
| | - Douglas Singini
- School of Public Health and Health Systems, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
| | - Francis Liywalii
- Provincial Health Office, Western Province, P.O. Box 910022, Mongu, Zambia
| | - Jacob Sakala
- Provincial Health Office, Western Province, P.O. Box 910022, Mongu, Zambia
| | | | - Paul W Shaw
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, SY23 3FG, UK
| |
Collapse
|