A cross-sectional observational study investigating the association between sedges (swamp grasses, Cyperaceae) and the prevalence of immature malaria vectors in aquatic habitats along the shore of Lake Victoria, western Kenya [version 2; peer review: 2 approved]
Background: Strategies that involve manipulations of the odour-orientation of gravid malaria vectors could lead to novel attract-and-kill interventions. Recent work has highlighted the potential involvement of graminoid plants in luring vectors to oviposition sites. This study aimed to analyse the a...
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| Format: | Article |
| Language: | English |
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F1000 Research Ltd
2020-10-01
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| Series: | F1000Research |
| Online Access: | https://f1000research.com/articles/9-1032/v2 |
| _version_ | 1818302147408691200 |
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| author | Getachew E. Bokore Paul Ouma Patrick O. Onyango Tullu Bukhari Ulrike Fillinger |
| author_facet | Getachew E. Bokore Paul Ouma Patrick O. Onyango Tullu Bukhari Ulrike Fillinger |
| author_sort | Getachew E. Bokore |
| collection | DOAJ |
| description | Background: Strategies that involve manipulations of the odour-orientation of gravid malaria vectors could lead to novel attract-and-kill interventions. Recent work has highlighted the potential involvement of graminoid plants in luring vectors to oviposition sites. This study aimed to analyse the association between water-indicating graminoid plants (Cyperaceae, sedges), other abiotic and biotic factors and the presence and abundance of early instar Anopheles larvae in aquatic habitats as a proxy indicator for oviposition. Methods: A cross-sectional survey of 110 aquatic habitats along the shores of Lake Victoria was done during the rainy season. Habitats were sampled for mosquito larvae using the sweep-net method and habitat characteristics recorded. Results: Anopheles arabiensis was the dominant species identified from aquatic habitats. Larvae of the secondary malaria vectors such as Anopheles coustani, An. rufipes and An. maculipalpis were found only in habitats covered with graminoids, whereas An. arabiensis, An. ziemanni and An. pharoensis were found in both habitats with and without graminoid plants. The hypothesis that sedges might be positively associated with the presence and abundance of early instar Anopheles larvae could not be confirmed. The dominant graminoid plants in the habitats were Panicum repens, Cynodon dactylon in the Poaceae family and Cyperus rotundus in the Cyperaceae family. All of these habitats supported abundant immature vector populations. The presence of early instar larvae was significantly and positively associated with swamp habitat types (OR=22, 95% CI=6-86, P<0.001) and abundance of late Anopheles larvae (OR=359, CI=33-3941, P<0.001), and negatively associated with the presence of tadpoles (OR=0.1, CI=0.0.01-0.5, P=0.008). Conclusions: Early instar malaria vectors were abundant in habitats densely vegetated with graminoid plants in the study area but no specific preference could be detected for any species or family. In search for oviposition cues, it might be useful to screen for chemical volatiles released from all dominant plant species. |
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| institution | Directory Open Access Journal |
| issn | 2046-1402 |
| language | English |
| last_indexed | 2024-12-13T05:34:17Z |
| publishDate | 2020-10-01 |
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| spelling | doaj.art-0a1bad2e916a48859d16c9dad8615c712022-12-21T23:57:58ZengF1000 Research LtdF1000Research2046-14022020-10-01910.12688/f1000research.25673.229842A cross-sectional observational study investigating the association between sedges (swamp grasses, Cyperaceae) and the prevalence of immature malaria vectors in aquatic habitats along the shore of Lake Victoria, western Kenya [version 2; peer review: 2 approved]Getachew E. Bokore0Paul Ouma1Patrick O. Onyango2Tullu Bukhari3Ulrike Fillinger4International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772–00100, Nairobi, KenyaInternational Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772–00100, Nairobi, KenyaSchool of Physical and Biological Sciences, Department of Zoology, Maseno University, P.O. Box 333 – 40105, Maseno, KenyaSchool of Physical and Biological Sciences, Department of Zoology, Maseno University, P.O. Box 333 – 40105, Maseno, KenyaInternational Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772–00100, Nairobi, KenyaBackground: Strategies that involve manipulations of the odour-orientation of gravid malaria vectors could lead to novel attract-and-kill interventions. Recent work has highlighted the potential involvement of graminoid plants in luring vectors to oviposition sites. This study aimed to analyse the association between water-indicating graminoid plants (Cyperaceae, sedges), other abiotic and biotic factors and the presence and abundance of early instar Anopheles larvae in aquatic habitats as a proxy indicator for oviposition. Methods: A cross-sectional survey of 110 aquatic habitats along the shores of Lake Victoria was done during the rainy season. Habitats were sampled for mosquito larvae using the sweep-net method and habitat characteristics recorded. Results: Anopheles arabiensis was the dominant species identified from aquatic habitats. Larvae of the secondary malaria vectors such as Anopheles coustani, An. rufipes and An. maculipalpis were found only in habitats covered with graminoids, whereas An. arabiensis, An. ziemanni and An. pharoensis were found in both habitats with and without graminoid plants. The hypothesis that sedges might be positively associated with the presence and abundance of early instar Anopheles larvae could not be confirmed. The dominant graminoid plants in the habitats were Panicum repens, Cynodon dactylon in the Poaceae family and Cyperus rotundus in the Cyperaceae family. All of these habitats supported abundant immature vector populations. The presence of early instar larvae was significantly and positively associated with swamp habitat types (OR=22, 95% CI=6-86, P<0.001) and abundance of late Anopheles larvae (OR=359, CI=33-3941, P<0.001), and negatively associated with the presence of tadpoles (OR=0.1, CI=0.0.01-0.5, P=0.008). Conclusions: Early instar malaria vectors were abundant in habitats densely vegetated with graminoid plants in the study area but no specific preference could be detected for any species or family. In search for oviposition cues, it might be useful to screen for chemical volatiles released from all dominant plant species.https://f1000research.com/articles/9-1032/v2 |
| spellingShingle | Getachew E. Bokore Paul Ouma Patrick O. Onyango Tullu Bukhari Ulrike Fillinger A cross-sectional observational study investigating the association between sedges (swamp grasses, Cyperaceae) and the prevalence of immature malaria vectors in aquatic habitats along the shore of Lake Victoria, western Kenya [version 2; peer review: 2 approved] F1000Research |
| title | A cross-sectional observational study investigating the association between sedges (swamp grasses, Cyperaceae) and the prevalence of immature malaria vectors in aquatic habitats along the shore of Lake Victoria, western Kenya [version 2; peer review: 2 approved] |
| title_full | A cross-sectional observational study investigating the association between sedges (swamp grasses, Cyperaceae) and the prevalence of immature malaria vectors in aquatic habitats along the shore of Lake Victoria, western Kenya [version 2; peer review: 2 approved] |
| title_fullStr | A cross-sectional observational study investigating the association between sedges (swamp grasses, Cyperaceae) and the prevalence of immature malaria vectors in aquatic habitats along the shore of Lake Victoria, western Kenya [version 2; peer review: 2 approved] |
| title_full_unstemmed | A cross-sectional observational study investigating the association between sedges (swamp grasses, Cyperaceae) and the prevalence of immature malaria vectors in aquatic habitats along the shore of Lake Victoria, western Kenya [version 2; peer review: 2 approved] |
| title_short | A cross-sectional observational study investigating the association between sedges (swamp grasses, Cyperaceae) and the prevalence of immature malaria vectors in aquatic habitats along the shore of Lake Victoria, western Kenya [version 2; peer review: 2 approved] |
| title_sort | cross sectional observational study investigating the association between sedges swamp grasses cyperaceae and the prevalence of immature malaria vectors in aquatic habitats along the shore of lake victoria western kenya version 2 peer review 2 approved |
| url | https://f1000research.com/articles/9-1032/v2 |
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