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Background Novel malaria vector control approaches aim to combine tools for maximum protection. This study aimed to evaluate novel and re-evaluate existing putative repellent ‘push’ and attractive ‘pull’ components for manipulating the odour orientation of malaria vectors in the peri-domestic space. Methods Anopheles arabiensis outdoor human landing catches and trap comparisons were implemented in large semi-field systems to (i) test the efficacy of Citriodiol® or transfluthrin-treated fabric strips positioned in house eave gaps as push components for preventing bites; (ii) understand the efficacy of MB5-baited Suna-traps in attracting vectors in the presence of a human being; (iii) assess 2-butanone as a CO2 replacement for trapping; (iv) determine the protection provided by a full push-pull set up. The air concentrations of the chemical constituents of the push–pull set-up were quantified. Results Microencapsulated Citriodiol® eave strips did not provide outdoor protection against host-seeking An. arabiensis. Transfluthrin-treated strips reduced the odds of a mosquito landing on the human volunteer (OR 0.17; 95% CI 0.12–0.23). This impact was lower (OR 0.59; 95% CI 0.52–0.66) during the push-pull experiment, which was associated with low nighttime temperatures likely affecting the transfluthrin vaporisation. The MB5-baited Suna trap supplemented with CO2 attracted only a third of the released mosquitoes in the absence of a human being; however, with a human volunteer in the same system, the trap caught < 1% of all released mosquitoes. The volunteer consistently attracted over two-thirds of all mosquitoes released. This was the case in the absence (‘pull’ only) and in the presence of a spatial repellent (‘push-pull’), indicating that in its current configuration the tested ‘pull’ does not provide a valuable addition to a spatial repellent. The chemical 2-butanone was ineffective in replacing CO2. Transfluthrin was detectable in the air space but with a strong linear reduction in concentrations over 5 m from release. The MB5 constituent chemicals were only irregularly detected, potentially suggesting insufficient release and concentration in the air for attraction. Conclusion This step-by-step evaluation of the selected ‘push’ and ‘pull’ components led to a better understanding of their ability to affect host-seeking behaviours of the malaria vector An. arabiensis in the peri-domestic space and helps to gauge the impact such tools would have when used in the field for monitoring or control. Graphical Abstract

A small-scale study with Mosi-guard Natural spray, an insect repellent containing Citriodiol, was performed to determine if it has virucidal activity against SARS-CoV-2. A liquid test examined the activity of the insect repellent and the individual components for virucidal activity. A surface contact test looked at the activity of the insect repellent when impregnated on a latex surface as a synthetic skin for potential topical prophylactic application. Both Mosi-guard Natural spray and Citriodiol, as well as other components of the repellent, had virucidal activity in the liquid contact test. On a latex surface used to simulate treated skin, the titre of SARS-CoV-2 was less over time on the Mosi-guard Natural-treated surface but virus was still recovered.

Za izdelavo magistrske naloge na to temo smo se odločili zaradi porasta uporabe pesticidov v preteklih nekaj letih. Namen same naloge je bila priprava nano/mikrokapsul iz biorazgradljivih polimerov, ki služijo kot nosilci biopesticida citriodiol. V laboratoriju smo izvedli sintezo mezoporoznega amorfnega silicijevega dioksida (silike) in nadaljnjo funkcionalizacijo mezoporoznega amorfnega silicijevega dioksida z razvejanim polietileniminom, da bi dobili funkcionalne nano/mikrokapsule kot dostavni sistem pesticidov. V sintetizirane nano/mikrokapsule smo enkapsulirali biopesticid citriodiol. S pomočjo različnih analiznih meritev smo primerjali dobljene vzorce mezoporozne silike in mezoporozne silike s polietileniminom. Velikost pridobljenih kapsul smo določili s pomočjo določitve velikosti delcev, disperznega indeksa in zeta potenciala. Za določitev morfološkega izgleda kapsul in določanje poroznosti pa smo uporabili vrstično elektronsko mikroskopijo SEM in Brunauer-Emmet-Tellerovo BET metodo. Fourierjevo transformacijsko infrardečo spektroskopijo smo uporabili za pridobivanje spektrov vzorcev z namenom določitve elementarne sestave. Dokazali smo prisotnost citriodiola znotraj kapsule, ne pa na sami površini. Z metodo plinske kromatografije smo določili hlapnost citriodiola v (mg/L) v zadanem časovnem intervalu (min). Dobljeni rezultati in spoznanja tekom izdelave magistrske naloge lahko služijo kot model za enkapsulacijo komercialno zelo uporabljenega pesticida, imenovanega klomazon. The increase in the application of the pesticides in the last couple of the years has influenced the topic of this paper. The purpose of the paper was to prepare nano/microcapsules from biodegradable polymers which serve as the carriers of the citriodiol biopesticide. The synthesis of mesoporous amorphous silicon dioxide (silica) and the funcionalization of the mesoporous amorphous silicon dioxide with the polyethylenimine have been done in the laboratory to obtain functional nano/microcapsules which serve as a carrier system for the pesticides. Citriodiol biopesticide was encapsulated in the synthetized nano/microcapsules. Through different analytical measurements obtained samples of mesoporous silica were compared to mesoporous silica with polyethylenimine. The side of the obtained capsules has been determined through dispersity index and zeta potential. Scanning electron microscopy and Brunauer-Emmet-Taller method have been used to determine morphological structures of the capsules and porosity. Fourier transform infrared spectroscopy (FTIR) with attenuated total reflection (ATR) has been used to determine the spectres of samples in order to attain the element content in the samples. The presence of citriodiol has been proven inside the capsule, and not on the surface. The volatility of citriodiol (mg/L) in a limited time period (min) has been determined by using gas chromatography (GC). The results and findings obtained in the research can serve as a model to encapsulate clomaze pesticide, which is often used commercially.

Bugs, such as microorganisms and insects, are present in the environment and sometimes can be health-hazardous if the living environment is not maintained following proper hygienic regulations. In the present scenario of increasing public awareness, environmental consciousness, and growing demand for easy-care, and disinfected textiles, the manufacturing of protective and easy-to-care textiles has become a key necessity of the modern world. Comfortable, clean, hygienic, antimicrobial, and insect repelling properties of textile goods are gaining the accelerating research momentum as a basic requirement to produce multifunctional textiles. These functional finishes have numerous applications such as in-home textiles, bed nets, and tenting, camping gear as well as in military uniforms. Synthetic antimicrobial and insect repellents are quite effective against insects and microscopic organisms but are slightly toxic to the human being and the environment. To overcome these problems, researchers are considering natural agents for functional finishes, but their effectiveness is less durable to textile material. Besides needful advantages, the excessive use of dyes in finishing processes heavily required washing cycles and ultimately release various types of hazardous dyes or wasteful effluents in the environment. This review reports the chemical composition and recent developments in textile finishes, particularly antimicrobial and insect repellent textile finishes. A large number of commonly used antimicrobial agents (i.e. chitosan, zwitterionic compounds, silver and silver-based compounds, titanium dioxide nanoparticles, imidazolium salts, triclosan and quaternary ammonium salts) and insect repellent textile finishes (i.e. N‑N‑diethyl‑m‑toluamide, permethrin, cypermethrin, pyrethrum, picaridin, bioallethrin, citriodiol and essential oils) have been presented. Finally, the review is wrapped up with major research gaps/challenges, concluding remarks, and future opportunities in this area of research.

Fabric treatments with β-Cyclodextrins (β-CD) have been studied for different applications as nanotechnologycal approaches to achieve functional textiles. In particular, repellents and insecticides have been incorporated in β-CD treated textiles to prolong their release. In this case, Citriodiol®, a naturally derived mosquito repellent, was incorporated to β-CD treated polyester (PET) nets. Two methods for citriodiol inclusion were studied; i) pipette dripping or ii) impregnation of fabric in a plastic bag, in order to increase the repellent activity of PET textile substrates. Release profiles were analyzed by gas chromatography and repellency was monitored by in vivo assays with Aedes aegypti mosquitoes. Long lasting and reloadable mosquito repellent nets could be achieved by treating PET knits with citriodiol/β-CD complexes., Centro de Estudios Parasitológicos y de Vectores

Namen diplomske naloge je bil priprava okolju prijaznih etil celuloznih mikrokapsul s citriodiolom, ki bodo omogočale kontrolirano sproščanje izbrane organske snovi v okolico. Sintetizirali smo jih s homogeniziranjem organske in vodne faze. Ugotovili smo, da so bile mikrokapsule, ki so nastale ob mešanju s homogenizatorjem, bolj enakomernih velikosti kot tiste, mešane z magnetnim mešalom. Nastale mikrokapsule smo okarakterizirali z določitvijo polidisperznega indeksa, velikosti nastalih delcev in zeta potenciala. Ugotovljena je bila odvisnost velikosti nastalih mikrokapsul od načina mešanja, pri dodajanju organske faze k vodni fazi. Sproščanje citriodiola iz mikrokapsul smo merili z UV/VIS spektroskopijo, pri čemer smo spremljali časovno spreminjanje absorbance pri določeni valovni dolžini. Vrednosti merjenih absorbanc se po eno mesečnem merjenju niso znatno spremenile, kar pripisujemo zanemarljivi količini sproščenega citriodiola. Z merjenjem FTIR spektra citriodiola, etil celuloze in nastalih mikrokapsul, smo ugotavljali prisotnost aktivne komponente na ovoju ali v notranjosti mikrokapsule. Zaradi ujemajočih FTIR spektrov etil celuloze in vzorca etil celuloznih mikrokapsul, smo potrdili prisotnost citriodiola v notranjosti mikrokapsul. Nahajanje citriodiola v jedru mikrokapsul, je bilo vidno tudi s konfokalnim mikroskopom. The purpose of the diploma thesis was the preparation of environmentally friendly ethyl cellulose microcapsules with citriodol, which will enable the controlled release of the selected organic matter into the environment. They were synthesized by homogenizing the organic and aqueous phase. It was found that the microcapsules formed when mixed with the homogenizer were more uniform than those mixed with a magnetic stirrer. The resulting microcapsules were characterized by the determination of the polydispersion index, the size of the resulting particles and the zeta potential. The dependence of the size of the resulting microcapsules on the method of mixing while adding the organic phase to the aqueous phase was determined. The release of citriodol from microcapsules was measured by UV / VIS spectroscopy, while the time-varying absorbance was monitored at certain wavelengths. The values of the measured absorbances did not change significantly after one month, which is attributed to the negligible amount of released citriodiol. By measuring the FTIR spectrum of citriodiol, ethyl cellulose and the resulting microcapsules, the presence of the active component on the wall or core of the microcapsules was determined. Due to the matching FTIR spectra of ethyl cellulose and the sample of ethyl cellulose microcapsules, the presence of citriodiol in the microcapsules was confirmed. The finding of citriodol in the core of the microcapsules was also apparent with a confocal microscope.

Insect repellent textiles are currently being investigated as a complementary tool to control disease vectors, such as mosquitoes. The application of microencapsulated biopesticides to textiles is a promising low-toxicity alternative to other control methods, as microcapsules may prolong the release of the repellent agent. In this work, microcapsules containing two biopesticides, namely citronella essential oil and citriodiol® were prepared and applied to cotton textiles using a variety of techniques. The aim of this work was to evaluate these functional textiles to select the most efficient, durable systems. Citriodiol-treated cotton presented a prolonged durability, and 100% repellency could be achieved for more than 30 days after padding onto cotton fabrics. It has to be pointed out that all these repellent textiles have been obtained by scalable, low-cost methods which would require no additional investment for textile finishing industries., Facultad de Ciencias Naturales y Museo, Centro de Estudios Parasitológicos y de Vectores

Para el control de eficacia de los repelentes de insectos, la mayoria de los estudios se han realizado sobre voluntarios expuestos a la picadura de mosquitos ya sean enjaulados o volando en libertad. En este trabajo se presenta una alternativa para valorar la eficacia de estos producto sutilizando un sistema mecanico de atraccion y captura de insectos. Se realiza un trabajo de campo para estudiar la capacidad repelente de Mosi-Guard ® utilizando dos trampas de luz blanca analogas a las descritas por las directrices de los CDC (Centers for Disease Control and Prevention) para estudios poblacionales de mosquitos. Los resultados demuestran que este preparado es eficaz como repelente cuando se impregna una de las trampas y se la compara con los valores de otra analoga en la que no se ha aplicado producto, y se obtiene diferencias estadisticamente significativas.