Deltamethrin as inductor agent of precocious ovarian degeneration in Rhipicephalus sanguineus s.l. (Acari: Ixodidae) ticks

Abstract

The cosmopolitan species Rhipicephalus sanguineus s.l. is one of the most widely distributed ticks all over the world. These ectoparasites are vectors of several pathogens and cause significant direct damage to their hosts. The biological success of these ectoparasites has been attributed to their ovaries and salivary glands, organs that ensure their survival in various environmental conditions. The importance of the ovaries in ticks is that, after mating, the individuals are able to lay approximately three thousand eggs. The present study had the objective to demonstrate the effects of deltamethrin obtained from the product Butox P CE 25 (MSD Saúde Animal, São Paulo, Brazil) on the ovarian development of R. sanguineus s.l. females. The chemical was tested in the concentrations of 25, 50, 100 and 200 ppm (respectively 80, 40, 20 and 10 times lower than the recommended by the manufacturer). Through the application of histological techniques and HE staining, the results showed that the deltamethrin was potentially able to modify the morphophysiology of the oocytes in all developmental stages, interfering in the vitellogenesis, causing intense vacuolation, cytoplasmic disorganization, and alterations in the chorion secretion. In addition, the chemical affected the germ vesicle of some oocytes, causing damages and hypertrophy, fragmenting the chromatin and forming bodies strongly stained by hematoxylin. Therefore, this study confirmed that the deltamethrin had an important action on the reproductive system of the R. sanguineus s.l. females, causing the precocious structural disorganization of the germ cells, consequently preventing the generation of new individuals.

The effect of sublethal concentrations of deltamethrin and alphacypermethrin on the fecundity and development of Ixodes ricinus (Acari: Ixodidae) eggs and larvae

“…Our results correspond with the investigations carried out by other authors (Friesen and Kaufman 2003;Oliveira et al 2008;Roma et al 2010;Camargo-Mathias et al 2017), who demonstrated cytotoxic effects of pyrethroids on the tick reproductive system. Cypermethrin inhibited oocyte development in Amblyomma hebraeum Koch (Friesen and Kaufman 2003).…”

Modulation of the PGE2-Mediated Pathway in the Eclosion Blocking Effect of Flumethrin and Terpenoid Subfraction Isolated from Artemesia nilagirica in Rhipicephalus annulatus

“…Oocytes were deformed with the break in the nucleus region. The abnormal morphological and structural changes observed in the present study were previously reported in the ovaries of the ticks treated with other phytoacaricides [ 21 , 29 ] and synthetic acaricides like deltamethrin, amitraz [ 38 , 39 , 40 ], fipronil [ 33 , 34 ], permethrin [ 36 , 37 ] and cypermethrin [ 74 ]. The above studies indicated the inhibitory effect of these acaricides on the oocytes at different stages of their development.…”

“…In addition to their direct acaricidal activity due to neurotoxicity, many herbal extracts produced accelerated degeneration of salivary glandular tissue and changes in the morphophysiology of reproductive organs in ticks [ 19 , 20 ]. The histopathological and ultrastructural alterations induced by phytoacaricides [ 19 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ] were comparable to those induced by conventional synthetic chemical acaricides [ 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ].…”

Morphophysiological analysis of the salivary glands of Rhipicephalus sanguineus sensu lato (Acari: Ixodidae) exposed to ozonated water: A control strategy

“…is the application of synthetic chemical acaricides. Among these are fipronil, able to cause alterations in the reproductive system and salivary glands (Oliveira et al ., 2007, 2009; Pereira et al ., 2009, 2011); permethrin, which causes degeneration of the synganglion and alterations in the salivary glands and reproductive system (Nodari et al ., 2011, 2012a; Roma et al ., 2011, 2013, 2014); fluazuron, which acts on the integument and midgut (Oliveira et al ., 2012, 2013, 2014); dinotefuran, which acts on the reproductive system of females (Oliveira et al ., 2016, 2017); and deltamethrin, which affects the synganglion and the reproductive system of females (Camargo‐Mathias et al ., 2017; Pereira et al ., 2017). Despite their efficacy, the indiscriminate application of acaricides has several disadvantages, including toxicity to non‐target organisms and environmental contamination (Camargo‐Mathias, 2013, 2018).…”