Bicomponent fibres for controlled release of volatile mosquito repellents.

Core-sheath structured fibres were developed for application as part of an alternative malaria vector control intervention aimed at reducing outdoor malaria transmission. The fibres were prepared by melt spinning of high density polyethylene (HDPE) as sheath and with a concentrate containing volatile N,N-Diethyl-m-toluamide (DEET) in poly(ethylene-co-vinyl acetate) (EVA) as core. The concentrate was prepared by a simple absorption processes to a content up to 40 wt% DEET. Scanning electron microscope imaging confirmed the formation of a bicomponent core-sheath fibre structure. Confocal Raman spectroscopy revealed the development of a concentration gradient of DEET in the sheath layer, suggesting a diffusion controlled release process. Excellent processability was demonstrated on an extrusion system melt spinning with take up speeds reaching 3000 m min-1. Sample textiles knitted from such filaments showed high residual repellence activity even after 20 cold washes or after eight months ageing under laboratory conditions. These findings indicate that this technology offers an alternative way to prevent outdoor mosquito bites in an effective and affordable manner.

[1]  C. Costantini,et al.  Field evaluation of the efficacy and persistence of insect repellents DEET, IR3535, and KBR 3023 against Anopheles gambiae complex and other Afrotropical vector mosquitoes. , 2004, Transactions of the Royal Society of Tropical Medicine and Hygiene.

[2]  Hélène Guis,et al.  Changes in Anopheles funestus biting behavior following universal coverage of long-lasting insecticidal nets in Benin. , 2012, The Journal of infectious diseases.

[3]  R. Hunt,et al.  Biting behaviour of African malaria vectors: 1. where do the main vector species bite on the human body? , 2015, Parasites & Vectors.

[4]  J. Sachs,et al.  The economic burden of malaria. , 2001, The American journal of tropical medicine and hygiene.

[5]  G. Koren,et al.  DEET-based insect repellents: safety implications for children and pregnant and lactating women. , 2003, CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne.

[6]  J. Sachs,et al.  The economic and social burden of malaria , 2002, Nature.

[7]  M. Faulde,et al.  A new clothing impregnation method for personal protection against ticks and biting insects. , 2006, International journal of medical microbiology : IJMM.

[8]  C. de Jager,et al.  Mosquito-borne arboviruses of African origin: review of key viruses and vectors , 2018, Parasites & Vectors.

[9]  C. A. Lawrence,et al.  Fundamentals of Spun Yarn Technology , 2003 .

[10]  R. Wirtz,et al.  Field evaluation of arthropod repellents, deet and a piperidine compound, AI3-37220, against Anopheles funestus and Anopheles arabiensis in western Kenya. , 1996, Journal of the American Mosquito Control Association.

[11]  R. Hunt,et al.  Repellent effects on Anopheles arabiensis biting humans in Kruger Park, South Africa , 2001, Medical and veterinary entomology.

[12]  P. Schlagenhauf,et al.  The efficacy of repellents against Aedes, Anopheles, Culex and Ixodes spp. - a literature review. , 2013, Travel medicine and infectious disease.

[13]  R. Hunt,et al.  Biting pattern and host-seeking behavior of Anopheles arabiensis (Diptera: Culicidae) in northeastern South Africa. , 1994, Journal of medical entomology.

[14]  Mustapha Debboun,et al.  Insect Repellents : Principles, Methods, and Uses , 2006 .

[15]  J. Xin,et al.  N, N-diethyl-m-toluamide-containing microcapsules for bio-cloth finishing. , 2007, The American journal of tropical medicine and hygiene.

[16]  A. Mills,et al.  The economics of malaria and its control , 2003 .

[17]  P. Leggat,et al.  Socio-cultural insights and lymphatic filariasis control – lessons from the Pacific , 2007, Filaria journal.

[18]  Tanya L Russell,et al.  Increased proportions of outdoor feeding among residual malaria vector populations following increased use of insecticide-treated nets in rural Tanzania , 2011, Malaria Journal.

[19]  H. Brünig,et al.  Melt-spinning of LDH/HDPE nanocomposites , 2013 .

[20]  B. Knols,et al.  DEET microencapsulation: a slow-release formulation enhancing the residual efficacy of bed nets against malaria vectors. , 2008, Transactions of the Royal Society of Tropical Medicine and Hygiene.

[21]  T. Ramachandran,et al.  Microencapsulation of lemon grass oil for mosquito repellent finishes in polyester textiles , 2011 .

[22]  Marcel Tanner,et al.  Malaria eradication back on the table. , 2008, Bulletin of the World Health Organization.

[23]  R. Snow,et al.  Malaria in Africa: progress and prospects in the decade since the Abuja Declaration , 2010, The Lancet.

[24]  M. Rowland,et al.  Indoor residual spraying with microencapsulated DEET repellent (N, N-diethyl-m-toluamide) for control of Anopheles arabiensis and Culex quinquefasciatus , 2014, Parasites & Vectors.

[25]  S. Weaver,et al.  Present and future arboviral threats. , 2010, Antiviral research.

[26]  P. Carnevale,et al.  Efficacy of Permethrin-Treated Uniforms in Combination with DEET Topical Repellent for Protection of French Military Troops in Côte d’Ivoire , 2004, Journal of medical entomology.

[27]  C. Schreck,et al.  Effectiveness of personal protection against mosquitoes in Alaska. , 1988, Journal of medical entomology.

[28]  C. Sousa,et al.  Raised houses reduce mosquito bites , 2003, Malaria Journal.

[29]  Anne Mills,et al.  The economic impact of malaria in Africa: a critical review of the evidence. , 2003, Health policy.

[30]  R. Xue,et al.  Laboratory Evaluation of Mosquito Repellents Against Aedes albopictus, Culex nigripalpus, and Ochlerotatus triseriatus (Diptera: Culicidae) , 2004, Journal of medical entomology.

[31]  D. Durrheim,et al.  Malaria outbreak control in an African village by community application of ‘deet’ mosquito repellent to ankles and feet , 2002, Medical and veterinary entomology.