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Application of plant extracts and plant-based formulations is one of the sustainable methods for the management of resistant ticks and thus managing the tick-borne diseases. In the present study, we comprehensively analyzed the research papers based on the acaricidal activity of plant extracts. A meta-analysis was conducted with an aim to highlight the potential candidates for further research for the development of ecofriendly and sustainable anti-tick herbal formulations. A total of 52 papers were analyzed up until December 2023, sourced from extensive searches of databases such as PubMed, Scopus, Science Direct and Google Scholar, focusing on the acaricidal activity of various plants against tick species. The plants belonging to Annonaceae and Burseraceae families were found significantly effective against ticks. Amongst the tick species, Rhipicephalus microplus was the highly studied tick species followed by Haemaphysalis bispinosa and Hyalomma dromedarii. The most responsive tick species to plant extracts were Hyalomma dromedarii and Ambylomma cajannense. With respect to the parts of the plants used, leaf (45%) was extensively utilized while the extracts prepared from the resin, stem and fruit peel of the plant showed highest acaricidal activity. The present study highlighted significant variability in the effectiveness of plant extracts depending on the plant species, plant parts used, type of extractant, and the tick species tested. These findings emphasize the need to develop a Standard Operating Protocol (SOP) for evaluating phytocompounds. Future research should prioritize isolating active compounds, elucidating their mechanisms of action, and optimizing formulations to ensure sustainable and effective tick management strategies.Article HighlightsPlant extracts and formulations offer eco-friendly solutions to tackle resistant ticks and manage tick-borne diseases.Effectiveness depended on the plant species, plant parts, type of extractant, and tick species tested.Focus required on isolating active compounds, understanding mechanisms of action, and optimizing formulations for sustainable tick control strategies.

Globally, ticks rank second only to mosquitoes as vectors of deadly pathogens affecting humans and first in transmitting animal pathogens, presenting a significant challenge to human wellness and sustainability of livestock-based industries. Traditional tick control via chemical acaricides impacts on the environment and has led to the emergence of multi-acaricide-resistant tick populations. Use of immunoprophylactic, along with other components of integrated tick management, holds the potential to mitigate tick infestations in a sustainable manner. To control multi-species tick infestations, the concept of a cocktail vaccine comprising of more than one antigens has emerged as a viable solution due to the inconsistent efficacy of single antigen-based immunization protocol. In this study, a dual antigen cocktail immunization protocol was developed targeting ferritin2 (FER2) and tropomyosin (TPM) proteins, which are associated with ticks' essential cellular and physiological functions, like blood iron homeostasis and muscle contractions. Dual gene silencing of FER2 and TPM genes in resulted in a 75.3% reduction in infested ticks, a 95.4% decrease in egg masses, and a complete loss of egg hatching when compared to control ticks. Microscopically, an altered ovarian cellular architecture, marked by vacuolation and reduced nucleus-to-cytoplasmic ratio were noted in the gene knocked down ticks. An immunization with cocktails of 300 µg dose of each protein, rHaFER2 and rHaTPM was standardized in a rat model and was used to immunize cross-bred ( x ) male cattle with Montanide ISA 50V2 adjuvant on days 0, 28, and 49. A significant ( < 0.001) IgG and IgG2 antibody response was observed in the immunized animals with high IgG levels sustained until day 119 post-primary immunization, showing a 4.1-fold increase over the pre-immunization period. The animals were challenged with larvae and adults of and larvae of . Immunization with the cocktail antigen resulted an efficacy of 70% and 76% against larvae and adults, respectively, and 54% against infestations. Compared to single-antigen immunization, the immunization with cocktail antigens demonstrated higher protection against and ticks. The results advance the development of cocktail vaccines to control multiple tick species.

Pu.1 is an ETS family transcription factor (TF) that plays critical roles in erythroid progenitors by promoting proliferation and blocking terminal differentiation. However, the mechanisms controlling expression and down-regulation of Pu.1 during early erythropoiesis have not been defined. In this study, we identify the actions of Runx1 and Pu.1 itself at the Pu.1 gene Upstream Regulatory Element (URE) as major regulators of Pu.1 expression in Burst-Forming Unit erythrocytes (BFUe). During early erythropoiesis, Runx1 and Pu.1 levels decline, and chromatin accessibility at the URE is lost. Ectopic expression of Runx1 or Pu.1, both of which bind the URE, prevents Pu.1 down-regulation and blocks terminal erythroid differentiation, resulting in extensive ex vivo proliferation and immortalization of erythroid progenitors. Ectopic expression of Runx1 in BFUe lacking a URE fails to block terminal erythroid differentiation. Thus, Runx1, acting at the URE, and Pu.1 itself directly regulate Pu.1 levels in erythroid cells, and loss of both factors is critical for Pu.1 down-regulation during terminal differentiation. The molecular mechanism of URE inactivation in erythroid cells through loss of TF binding represents a distinct pattern of Pu.1 regulation from those described in other hematopoietic cell types such as T cells which down-regulate Pu.1 through active repression. The importance of down-regulation of Runx1 and Pu.1 in erythropoiesis is further supported by genome-wide analyses showing that their DNA-binding motifs are highly overrepresented in regions that lose chromatin accessibility during early erythroid development.

Prostaglandins are a group of important cell-signaling molecules involved in the regulation of ovarian maturation, oocyte development, egg laying and associated behaviors in invertebrates. However, the presence of prostaglandin E2 (PGE2), the key enzymes for PGE2 biosynthesis and its interference by drugs were not investigated previously in the ovary of ticks. The present study was undertaken to assess the modulation of the PGE2-mediated pathway in the eclosion blocking effect of flumethrin and terpenoid subfraction isolated from Artemisia nilagirica in Rhipicephalus annulatus ticks. The acaricidal activities and chemical profiling of the terpenoid subfraction were performed. The localization of the cyclooxygenase1 (COX1) and prostaglandin E synthase (PGES) enzymes and the quantification of PGE2 in the ovaries of the ticks treated with methanol (control), flumethrin and terpenoid subfraction were also undertaken. In addition, the vitellogenin concentration in hemolymph was also assayed. Both flumethrin and the terpenoid subfraction of A. nilagirica elicited a concentration-dependent inhibition of fecundity and blocking of hatching of the eggs. The COX1 could not be detected in the ovaries of treated and control ticks, while there was no significant difference observed in the concentration of vitellogenin (Vg) in them. The presence of PGES in the oocytes of control ticks was confirmed while the immunoreactivities against PGES were absent in the vitellogenic oocytes of ticks treated with flumethrin and terpenoid subfraction. The levels of PGE2 were below the detection limit in the ovaries of the flumethrin-treated ticks, while it was significantly lower in the ovaries of the terpenoid subfraction-treated ticks. Hence, the prostaglandin E synthase and PGE2 were identified as very important mediators for the signaling pathway for ovarian maturation and oviposition in ticks. In addition, the key enzyme for prostaglandin biosynthesis, PGES and the receptors for PGE2 can be exploited as potential drug targets for tick control. The detection of PGES by immunohistochemistry and quantification of PGE2 by LC-MSMS can be employed as valuable tools for screening newer compounds for their eclosion blocking acaricidal effects.

To identify suitable targets for development of cross-protective tick vaccine, in silico analysis was attempted and male tick derived molecule, voraxin-α was targeted. The voraxin-α homologue of Rhipicephalus (Boophilus) microplus was cloned, sequenced and analyzed employing standard methods. The deduced amino acids sequence analysis of the 419 bp cloned voraxin-α gene of R. (B.) microplus indicated very high (94.6 %) similarity with voraxin-α of the R. appendiculatus and moderate to low identity with Amblyomma hebraeum, Dermacentor silvarum and Haemaphysalis longicornis. The results suggest that recombinant voraxin-α might be a good candidate as cross-protective anti-tick vaccine.

The present study compares the in vitro efficacy of four chemical acaricides, viz. amitraz, coumaphos, deltamethrin and lindane, against Rhipicephalus (Boophilus) annulatus and Haemaphysalis bispinosa ticks based on adult immersion tests. Amitraz, at 350 ppm, elicited 29.2 ± 4.17% mortality against R. (B.) annulatus, 100% inhibition of fecundity and absence of hatching of eggs laid by treated ticks. The same compound at 300 ppm caused 62.5 ± 12.5% mortality against H. bispinosa, 96.7% inhibition of fecundity and complete blocking of eclosion. The LC50 value of amitraz against susceptible H. bispinosa was 181 ppm. Deltamethrin at 400 ppm, elicited 25.0 ± 4.81% adult R. (B.) annulatus mortality, 97.5% inhibition of fecundity and absence of egg hatching. Complete blocking of egg hatching was observed even at 30 ppm. However, deltamethrin (at 50 ppm) elicited 75.0 ± 10.76% mortality against H. bispinosa, 65.8% inhibition of fecundity and very low egg hatching (10%). The LC50 for deltamethrin against susceptible H. bispinosa was 33.8 ppm. Coumaphos at 50 ppm, caused mortality of 70.8 ± 4.17% with R. (B.) annulatus whereas 100% mortality was observed against H. bispinosa. The LC50 values of coumaphos against R. (B.) annulatus and H. bispinosa were 9 and 8.75 ppm, respectively. Complete inhibition (100%) of fecundity was observed even at 30 ppm against both parasites. Complete blocking of egg hatching was also observed even at 10 ppm of coumaphos. Lindane at 1000 ppm caused mortality of 87.5 ± 7.98% against R. (B.) annulatus and 83.3% mortality against H. bispinosa at 100 ppm. The LC50 values of lindane against R. (B.) annulatus and H. bispinosa were 157 and 8.61 ppm, respectively. Complete inhibition of fecundity was observed with R. (B.) annulatus treated with lindane above 200 ppm and with H. bispinosa at a concentration above 50 ppm. Complete blocking of egg hatching was observed in R. (B.) annulatus, even at 100 ppm. Lindane caused 100% blocking of egg hatching at 1 ppm in the case of H. bispinosa.

Background: We aimed to focus on the ixodid ticks parasitizing wild mammals and reptiles from Wayanad Wildlife Sanctuary, Western Ghat, southern India. Methods: The taxonomic identification of ticks collected from wild mammals and reptiles was performed based on the morphology of adults. Results: We revealed eight species of ticks including, Amblyomma integrum, Rhipicephalus (Boophilus) annulatus, Haemaphysalis (Kaiseriana) spinigera, H. (K.) shimoga, H. (K.) bispinosa, H. (Rhipistoma) indica, Rhipicephalus haemaphysaloides and R. sanguineus  s.l. collected from nine species of wild mammals while four tick species Ablyomma kraneveldi, A. pattoni, A. gervaisi and A. javanense parasitizing on four species of reptiles. The highest host rich­ness was shown by H. (K.) bispinosa and R. haemaphysaloides parasitizing six and five different host species, re­spectively.  Reports of R. (B.) annulatus on sambar deer, A. javanense and A. kraneveldi on python as well as A. pat­toni on Indian rat snake are the new host records from this region. Conclusion: Eight species of ticks parasitizing on nine species of wild mammals and four species of parasitizing on four species of reptiles were identified. The highest host richness was shown by H. (K.) bispinosa and R. haemaphy­saloides. H. spinigera as the vector of KFD was also identified in this study.

The present communication describes the detailed day wise study of histological changes of the ovary of Rhipicephalus (Boophilus) annulatus in the postengorgement period together with the systematic classification of their oocytes. The ovary of R. (B.) annulatus is panoistic type with an asynchronous development of oocytes. All the stages (II, III, IV, and V) of oocytes except stage I were similar to R. (B.) microplus. The stage I oocytes showed basophilia, which was not reported earlier in other species of ticks. Day wise changes were in the form of presence of oogonia in partially fed and day one engorged adults, considerable degeneration of oocytes on day two, emergence of new wave of oocytes on day three, presence of mature oocytes up to day eight, and complete degeneration of ovarian tissue from day eight onwards. The degenerative changes in the ovary appeared initially in the oocytes followed by germinal epithelium.

The acaricidal activity of the petroleum ether extract of leaves of Tetrastigma leucostaphylum (Dennst.) Alston (family: Vitaceae) against Rhipicephalus (Boophilus) annulatus was assessed using adult immersion test (AIT). The per cent of adult mortality, inhibition of fecundity, and blocking of hatching of eggs were studied at different concentrations. The extract at 10% concentration showed 88.96% inhibition of fecundity, 58.32% of adult tick mortality, and 50% inhibition of hatching. Peak mortality rate was observed after day 5 of treatment. Mortality of engorged female ticks, inhibition of fecundity, and hatching of eggs were concentration dependent. The LC50 value of the extract against R. (B.) annulatus was 10.46%. The HPTLC profiling of the petroleum ether extract revealed the presence of at least seven polyvalent components. In the petroleum ether extract, nicotine was identified as one of the components up to a concentration of 5.4%. However, nicotine did not reveal any acaricidal activity up to 20000 ppm (2%). Coconut oil, used as diluent for dissolving the extract, did not reveal any acaricidal effects. The results are indicative of the involvement of synergistic or additive action of the bioactive components in the tick mortality and inhibition of the oviposition.

The present study investigated the effect of ivermectin and amitraz on the cellular architecture of vital organs of Rhipicephalus microplus. Adult female ticks were treated with lethal concentrations (LC 95 ) of ivermectin and amitraz, and the ovaries, synganglion, and Gené’s organ were processed 48 h post treatment. In both the treatment groups, the ultra-thin sections of ovary exhibited deformed oocytes, irregular plasmic membrane and chorion layer, extensive vacuolation in the cytoplasm mainly at periphery of the cell and oocyte-pedicel junction. Marked vacuolations in the cortex and neuropile region with significant structural disorganization of the neural fibers were common alterations observed in the synganglion of ticks exposed to ivermectin and amitraz. The tissue sections of Gené’s organ revealed deformed tubular glands with severe loss of cellular limit of secretory epithelium and cytoplasmic vacuolations in the ivermectin treated ticks whereas, the alterations were comparatively less severe in amitraz exposed ticks. The cellular deformities in these vital organs probably impaired reproductive function, nerve signal transmission and metabolic activities and thus affected fecundity and survivability of the treated ticks. The findings suggested that the action of ivermectin and amitraz are not restricted to the nervous system of ticks, but also on other vital organs, ovary and Gené’s organ affecting the oviposition. The study provided insights into the development of targeted interventions for tick control strategies.