Cymbopogon citratus and Lippia multiflora essential oils as alternative repellent to DEET against Anopheles gambiae s.l. in Bobo-Dioulasso, Burkina Faso

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Résumé

Personal protective tools, such as repellents, play a vital role in preventing mosquito-borne disease
transmission. Although N,N-diethyl-meta-toluamide (DEET), a synthetic repellent, is effective against
insects, it may cause allergic reactions. Therefore, there is a need to explore effective alternative
repellents exhibiting fewer side effects. Here, we assessed the repellent activity of essential oils
(EOs) from Lippia multiflora and Cymbopogon citratus alone and in combination, against Anopheles
populations, using the Human Landing Catch (HLC) method in Dogona, Burkina Faso. For this purpose,
five concentrations (0.5%, 1%, 1.5%, 2% and 2.5%) of each EO and their combination were applied
on 68 volunteers legs from 6 p.m. to 9 a.m. on two consecutive nights. Also, DEET and ethanol were
used as positive and negative controls respectively. As results, overall, houses with volunteers to
whom EOs had been applied showed a reduction in the mean human biting rate (HBR), both indoors
and outdoors (combination EO, 2.5%: 1.5 vs. control: 46.75 b h−1 n−1). This combination exhibits an
efficacy comparable to that of DEET (DEET: 2 b h−1 n−1). This repellent effect is likely attributable to
the dominant compounds present in the EOs namely, neral (44.7%) and geranial (55.2%) in C. citratus,
and β-caryophyllene (20.1%), p-cymene (14.6%), and thymol acetate (12.0%) in L. multiflora. When
the two essential oils were combined, they exhibited a synergistic repellent effect, resulting in a long
protection time. The use of EOs as repellents may reduce the number of mosquito infectious bites/
human/night, thereby contributing to a lower Entomological Inoculation Rate (EIR = 0.77). This study
highlights the promising repellent potential of C. citratus and L. multiflora EOs, against wild mosquito
populations.

Mots-clés

Essential oil, Repellent, Human landing catch, Mosquito control, Burkina Faso