Tick repellents and acaricides of botanical origin: a green roadmap to control tick-borne diseases?

Abstract

Arthropods are dangerous vectors of agents of deadly diseases, which may hit as epidemics or pandemics in the increasing world population of humans and animals. Among them, ticks transmit more pathogen species than any other group of blood-feeding arthropods worldwide. Thus, the effective and eco-friendly control of tick vectors in a constantly changing environment is a crucial challenge. A number of novel routes have been attempted to prevent and control tick-borne diseases, including the development of (i) vaccines against viruses vectored by ticks; (ii) pheromone-based control tools, with special reference to the "lure and kill" techniques; (iii) biological control programmes relying on ticks' natural enemies and pathogens; and (iv) the integrated pest management practices aimed at reducing tick interactions with livestock. However, the extensive employment of acaricides and tick repellents still remains the two most effective and ready-to-use strategies. Unfortunately, the first one is limited by the rapid development of resistance in ticks, as well as by serious environmental concerns. On the other hand, the exploitation of plants as sources of effective tick repellents is often promising. Here, we reviewed current knowledge concerning the effectiveness of plant extracts as acaricides or repellents against tick vectors of public health importance, with special reference to Ixodes ricinus, Ixodes persulcatus, Amblyomma cajennense, Haemaphysalis bispinosa, Haemaphysalis longicornis, Hyalomma anatolicum, Hyalomma marginatum rufipes, Rhipicephalus appendiculatus, Rhipicephalus (Boophilus) microplus, Rhipicephalus pulchellus, Rhipicephalus sanguineus and Rhipicephalus turanicus. Eighty-three plant species from 35 botanical families were selected. The most frequent botanical families exploited as sources of acaricides and repellents against ticks were Asteraceae (15 % of the selected studies), Fabaceae (9 %), Lamiaceae (10 %), Meliaceae (5 %), Solanaceae (6 %) and Verbenaceae (5 %). Regression equation analyses showed that the literature grew by approximately 20 % per year (period: 2005-2015). Lastly, in the final section, insights for future research are discussed. We focused on some caveats for future data collection and analysis. Current critical points mainly deal with (a) not uniform methods used, which prevent proper comparison of the results; (b) inaccurate tested concentrations, frequently 100 % concentration corresponded to the gross extract, where the exact amounts of extracted substances are unknown; and (c) not homogeneous size of tested tick instars and species. Overall, the knowledge summarized in this review may be helpful for comparative screening among extensive numbers of plant-borne preparations, in order to develop newer and safer tick control tools.

Acute toxicity and repellent activity of the Origanum scabrum Boiss. & Heldr. (Lamiaceae) essential oil against four mosquito vectors of public health importance and its biosafety on non-target aquatic organisms

“…Plant-borne insecticides, as well as essential oils (EOs), are encouraging since they are effective at reduced doses, environmental-friendly, biodegradable, and often economical (Benelli 2015b;Pavela 2015a;Govindarajan and Benelli 2016a, b, c;Govindarajan et al 2011Govindarajan et al , 2013a. Thus, recent research focused on plant EOs and extracts as possible sources of arthropod ovicidal, larvicidal, adulticidal, and repellent compounds (e.g., Cheng et al 2003Cheng et al , 2004Govindarajan 2010a;Govindarajan et al 2011;Dinesh et al 2015;Madhiyazhagan et al 2015;Murugan et al 2015a, b, c;Pavela 2015b;Suresh et al 2015;Benelli et al 2016b;Jaganathan et al 2016;Panneerselvam et al 2016).…”

Acaricidal activity of leaves of Morus nigra against the cattle tick Rhipicephalus microplus

“…Due to many difficulties in controlling and combating this arthropod, the use of medicinal plants is an increasingly viable alternative in developing countries like Brazil, considering the great variability of species, low cost, easy availability and rapid degradation compared to other chemicals, as well as reduction of the contamination of environment, animals and men (Agnolin, 2010), these are the main reasons for the study of plants that have real acaricide effect (Benelli et al, 2016).…”

“…Currently the plants with acaricide potential most researched are from the families Asteraceae, Fabaceae, Lamiaceae, Meliaceae, Solanaceae and Verbenaceae (Benelli et al, 2016). This study aimed to extract and evaluate the acaricidal activity of M. nigra leaves on the cattle tick R. microplus, using the adult immersion tests.…”

Do Chenopodium ambrosioides-Synthesized Silver Nanoparticles Impact Oryzias melastigma Predation Against Aedes albopictus Larvae?

“…Therefore, plant-based insecticides may serve as suitable alternative to synthetic molecules as they are environmentally safe, biodegradable, and are easily available in all parts of the world [4,10,16,53,124]. In addition, it is worthy to note that the toxicity of botanical-based biopesticides such as plant extracts and essential oils is usually exerted by multiple mechanisms of action, lowering the chances of resistance development in targeted arthropods [99].…”