To Kill or to Repel Mosquitoes? Exploring Two Strategies for Protecting Humans and Reducing Vector-Borne Disease Risks by Using Pyrethroids as Spatial Repellents

Abstract

Although control efforts are improving, vector-borne diseases remain a global public health challenge. There is a need to shift vector control paradigms while developing new products and programmes. The importance of modifying vector behaviour has been recognised for decades but has received limited attention from the public health community. This study aims to: (1) explore how the use of spatial repellents at sublethal doses could promote public health worldwide; (2) propose new methods for evaluating insecticides for use by the general public; and (3) identify key issues to address before spatial repellents can be adopted as complementary vector control tools. Two field experiments were performed to assess the effects of an insecticidal compound, the pyrethroid transfluthrin, on Aedes albopictus mosquitoes. The first examined levels of human protection, and the second looked at mosquito knockdown and mortality. For the same transfluthrin dose and application method, the percent protection remained high (>80%) at 5 h even though mosquito mortality had declined to zero at 1 h. This result underscores that it matters which evaluation parameters are chosen. If the overarching goal is to decrease health risks, sublethal doses could be useful as they protect human hosts even when mosquito mortality is null.

The Use of Insecticide Mosquito Nets and Insecticide Spraying on the Risk of Malaria in Children: A Meta-Analysis

“…The use of insecticides in controlling mosquito populations has proven to be effective but has negative impacts that need to be considered so that risks can be minimized or suppressed. Children who sleep under insecticide mosquito nets and live in houses that have been sprayed with insecticides are at risk of exposure to insecticide residues through inhalation (inhaling volatile residues), skin contact (touching residues on surfaces), and hand-to-mouth contact, thereby increasing the risk of ingesting residues (Moreno-Gómez et al, 2021). The application of insecticides with appropriate procedures, techniques, tools and doses according to recommenddations can reduce the risk of health hazards to humans and the environment (WHO, 2015;Damalas and Koutroubas, 2016) (WHO, 2015).…”

Biology, Control and Zoonotic Role of Disease Vectors

“…Placing a concrete layer on the bottom of the sand sewers to prevent water accumulation completely eliminated mosquito breeding and, therefore, the need for biocides in the modified structures. Moreno-Gómez et al [ 11 ] evaluated the effectiveness of the insecticide pyrethroid transfluthrin in providing protection against A. albopictus bites in humans, reporting high protection with mosquito mortality declining rapidly. In their comprehensive review, Morchón et al [ 12 ] shed light on the epidemiological landscape of heartworm disease in Europe, uncovering its alarming spread and establishment as an endemic condition.…”