Larval habitat stability and productivity in two sites in Southern Ghana
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Date
2023
Journal Title
Journal ISSN
Volume Title
Publisher
Malaria Journal
Abstract
Background Mosquito larval source management (LSM) is a valuable additional tool for malaria vector control.
Understanding the characteristics of mosquito larval habitats and its ecology in different land use types can give valuable insight for an effective larval control strategy. This study determined the stability and productivity of potential
anopheline larval habitats in two different ecological sites: Anyakpor and Dodowa in southern Ghana.
Methods A total of 59 aquatic habitats positive for anopheline larvae were identified, and sampled every two weeks
for a period of 30 weeks using a standard dipping method. Larvae were collected using standard dippers and were
raised in the insectary for identification. Sibling species of the Anopheles gambiae sensu lato (s.l.) were further identified by polymerase chain reaction. The presence of larval habitats, their stability and larvae positive habitats were
compared between the two sites using Mann–Whitney U and the Kruskal–Wallis test. Factors affecting the presence
of An. gambiae larvae and physicochemical properties at the sites were determined using multiple logistic regression
analysis and Spearman’s correlation.
Results Out of a total of 13,681 mosquito immatures collected, 22.6% (3095) were anophelines and 77.38% (10,586)
were culicines. Out of the 3095 anophelines collected, An. gambiae s.l. was predominant (99.48%, n=3079), followed
by Anopheles rufpes (0.45%, n=14), and Anopheles pharoensis (0.064%, n=2). Sibling species of the An. gambiae
consisted of Anopheles coluzzii (71%), followed by An. gambiae s.s. (23%), and Anopheles melas (6%). Anopheles mean
larval density was highest in wells [6.44 (95% CI 5.0–8.31) larvae/dip], lowest in furrows [4.18 (95% CI 2.75–6.36) larvae/
dip] and man-made ponds [1.20 (95% CI 0.671–2.131) larvae/dip].The results also revealed habitat stability was highly
dependent on rainfall intensity, and Anopheles larval densities were also dependent on elevated levels of pH, conductivity and TDS.
Conclusion The presence of larvae in the habitats was dependent on rainfall intensity and proximity to human settlements. To optimize the vector control measures of malaria interventions in southern Ghana, larval control should
be focused on larval habitats that are fed by underground water, as these are more productive habitats.
Description
Research Article
Keywords
Anopheles gambiae sensu lato, Larval habitat productivity, Larval habitat stability