26

■Bio-mathematics, Statistics and Nano-Technologies: Mosquito Control Strategies

The use of repellent is considered the main control means against the kissing bug Triatoma

infestans, that transmits a protozoan, Trypanosoma cruzi, which can infect animals and

people and are found only in the Americas causing Chagas disease. (Reynoso, Seccacini,

Calcagno, Zerba1, and Alzogaray 2017).

Plant-based repellents have been used for generations in traditional practice as a per-

sonal protection measure against host-seeking mosquitos. Knowledge on traditional re-

pellent plants obtained through ethnobotanical studies is a valuable resource for the de-

velopment of new natural products. A report has demonstrated the efficacy of botanical

compounds as insect repellents on domestic animals (Talbalaghi, Ali and Hassandoust,

2018). Recently, commercial repellent products containing plant-based ingredients have

gained increasing popularity among consumers, as these are commonly perceived as “safe”

in comparison to long-established synthetic repellents although this is sometimes a mis-

conception. To date, studies have followed standard WHO Pesticide Evaluation Scheme

guidelines for repellent testing. There is a need for further standardized studies in order to

better evaluate repellent compounds and develop new products that offer high repellence

as well as good consumer safety (Maia and Moore 2011). Botanical repellents are numer-

ous and target a wide variety of physiological targets and odorant receptors, suggesting

that the potential for resistance to these chemistries is sufficiently low. Current and future

technologies directed toward the development of long-lasting botanical or biorational re-

pellents could lead to promising alternatives to repellent formulations that are currently in

the market.

One of the major problems of natural repellents is how to establish a standard of its

efficacy action, to be reported in the description of the repellents or to be shown on the

label that promotes it. The molecules extracted from botanical essences, which form the

basis of certain repellents even from the same origin, growing in same latitude are grown

on different soil nutritional composition. The same plant species growing in different cli-

matic conditions, with alterations in compound composition of the repellent property and

efficacy may be as a result of different factors such as light, humidity, temperature and also

different processes involved in the preparation, which in extension alter the components of

the repellent itself.

3.4

TEXTILE AND PERSONAL PROTECTION

Many repellents can be applied to field clothing for protection against military im-

portant arthropods, especially those that crawl or hop (e.g., mites, ticks, fleas, body lice).

Repellents that are or have been widely used for clothing impregnation include sul- fur,

dimethyl phthalate, dibutyl phthalate, benzyl benzoate, deet, and permethrin. These mate-

rials are also effective when applied to bed nets, curtains, window screens, ground cloths,

tents, and protective over garments (Gupta, Gambel, Bernard and Schiefer 2006). Many in-

novative initiatives have been proposed by the University of Zagreb to make various fabrics

repellent against arthropods in recent years. The attempt of chemical and textile engineers

to combat Arbovirus mosquitos through textiles and paints explains the repellent efficacy

of fabric cotton samples (Grancaric, Botteri, Ghaffari 2019).