title: Field evaluation of picaridin repellents reveals differences in repellent sensitivity between Southeast Asian vectors of malaria and arboviruses.
abstract: Scaling up of insecticide treated nets has contributed to a substantial malaria decline. However, some malaria vectors, and most arbovirus vectors, bite outdoors and in the early evening. Therefore, topically applied insect repellents may provide crucial additional protection against mosquito-borne pathogens. Among topical repellents, DEET is the most commonly used, followed by others such as picaridin. The protective efficacy of two formulated picaridin repellents against mosquito bites, including arbovirus and malaria vectors, was evaluated in a field study in Cambodia. Over a period of two years, human landing collections were performed on repellent treated persons, with rotation to account for the effect of collection place, time and individual collector. Based on a total of 4996 mosquitoes collected on negative control persons, the overall five hour protection rate was 97.4% [95%CI: 97.1-97.8%], not decreasing over time. Picaridin 20% performed equally well as DEET 20% and better than picaridin 10%. Repellents performed better against Mansonia and Culex spp. as compared to aedines and anophelines. A lower performance was observed against Aedes albopictus as compared to Aedes aegypti, and against Anopheles barbirostris as compared to several vector species. Parity rates were higher in vectors collected on repellent treated person as compared to control persons. As such, field evaluation shows that repellents can provide additional personal protection against early and outdoor biting malaria and arbovirus vectors, with excellent protection up to five hours after application. The heterogeneity in repellent sensitivity between mosquito genera and vector species could however impact the efficacy of repellents in public health programs. Considering its excellent performance and potential to protect against early and outdoor biting vectors, as well as its higher acceptability as compared to DEET, picaridin is an appropriate product to evaluate the epidemiological impact of large scale use of topical repellents on arthropod borne diseases.
authors.affiliation: Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
authors.forename: Karel
authors.initials: K
authors.lastname: Van Roey
authors.affiliation: National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia.
authors.forename: Mao
authors.initials: M
authors.lastname: Sokny
authors.affiliation: Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
authors.forename: Leen
authors.initials: L
authors.lastname: Denis
authors.affiliation: Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
authors.forename: Nick
authors.initials: N
authors.lastname: Van den Broeck
authors.affiliation: National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia; Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia.
authors.forename: Somony
authors.initials: S
authors.lastname: Heng
authors.affiliation: National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia.
authors.forename: Sovannaroth
authors.initials: S
authors.lastname: Siv
authors.affiliation: Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
authors.forename: Vincent
authors.initials: V
authors.lastname: Sluydts
authors.affiliation: National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia.
authors.forename: Tho
authors.initials: T
authors.lastname: Sochantha
authors.affiliation: Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
authors.forename: Marc
authors.initials: M
authors.lastname: Coosemans
authors.affiliation: Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
authors.forename: Lies
authors.initials: L
authors.lastname: Durnez
mesh_terms: D000818:Animals; D001102:Arbovirus Infections / Q000635:transmission; D002160:Cambodia; D009033:Culicidae / Q000469:parasitology / Q000821:virology; D007302:Insect Repellents; D007303:Insect Vectors / Q000469:parasitology / Q000821:virology; D007305:Insecticide Resistance; D008288:Malaria / Q000635:transmission; D010880:Piperidines
chemical_list: D007302:Insect Repellents; D010880:Piperidines; C483506:picaridin