Integrative Alternative Tactics for Ixodid Control

Piroplasm infestations in cattle: exploring tick control using Chrysanthemum extract and neem oil emulsion

Introduction

Tick-borne diseases represent a major threat to both animal and human health globally. This study explores the prevalence of tick infestation and associated piroplasm infections specifically Theileria and Babesia species in cattle, in addition to evaluating the acaricidal effectiveness of Chrysanthemum extract (Dendranthema grandiflora) and neem oil emulsion (Azadirachta indica).

Methods

Among 130 cattle examined, 61 were infested with ticks and subsequently screened for piroplasm infections. Molecular analysis identified infections caused by Theileria annulata and Babesia bigemina.

Results

A strong association was found between tick infestation and Babesia species, while T. annulata infection showed a slight correlation. Hemolymph examination confirmed the critical role of ticks in the life cycle of piroplasm infection. Chrysanthemum extract and neem oil were tested for their acaricidal properties against adult ticks (Rhipicephalus annulatus). Chrysanthemum extract (0.5 mg/mL) caused tick mortality within 24 h. However, neem oil induced rapid and significant tick mortality at (20 mg/L) and (15 mg/L), achieving 100% mortality within the same time frame. Both treatments demonstrated high effectiveness, with results indicating strong dose-and time-dependent effects compared to controls. Scanning electron microscopy (SEM) revealed extensive morphological damage to treated ticks. This damage included destruction of the hypostome, loss of surface striations, wrinkling with pore formation, and cracking following exposure to neem oil and Chrysanthemum extract.

Discussion

These findings highlight the potential of D. grandiflora extract and neem oil emulsion as effective natural acaricides for controlling tick infestations and reducing tick-borne diseases.

Evaluation of acaricidal effect of terpinolene and γ-terpinene on Hyalomma anatolicum and in silico screening of herbs

IMPORTANCE

Terpenoids of a plant origin are a class of alternatives to chemical acaricides for tick control. Despite this, few studies have evaluated the efficacy of terpenoid-containing herbal extracts or individual terpenoids in Hyalomma anatolicum.

OBJECTIVE

This study evaluated the killing efficacy of terpinolene and γ-terpinene against H. anatolicum to identify herbs rich in these compounds as potential candidates for future materials in the control of H. anatolicum.

METHODS

Terpinolene and γ-terpinene were subjected to adult tick immersion experiments to evaluate their killing effect on H. anatolicum, following their identification post-collection. The herbs were screened for the two terpenoids using the HERB database, and the resulting data were categorized and analyzed.

RESULTS

The acaricidal effect of terpinolene and γ-terpinene against H. anatolicum showed a clear dose-response relationship, with effective doses LC₅₀ of 6.60 mg/mL and 4.86 mg/mL, respectively. In silico analysis revealed the presence of terpinolene and γ-terpinene in 52 and 36 herbs, respectively, with 16 herbs containing both compounds. These herbs could be grouped into 35 plant families. In particular, Lamiaceae and Apiaceae emerged as the most represented families, each accounting for 9.23% of the total herbs identified, followed by Zingiberaceae (7.69%) and Asteraceae and Rutaceae (6.15% each).

CONCLUSIONS AND RELEVANCE

Terpinolene and γ-terpinolene have good killing effects against H. anatolicum. Herbs rich in the two terpenoids are promising candidates as plant-derived materials for managing H. anatolicum.

Acaricidal activity of Brassicaceae seed meals on Ixodid ticks: a potential plant-based control agent

Ticks are a medically important group of arthropods, and their control has become a major challenge due to their widespread resistance to synthetic acaricides. Defatted seed meals of plants in the mustard family, commonly generated as byproducts of vegetable oil and biofuel production are known to possess pesticidal properties but their potential to control ticks remain poorly understood. We evaluated the bio-fumigation activity of defatted seed meals of three mustard family species, Brassica juncea (L) Czern. (PG), Lepidium sativum L. (Ls) and Thlaspi arvense L. (DFP), against three medically important hard tick species: Ambylomma americanum (L.) [Aa], Dermacentor variabilis (Say) [Dv] and Ixodes scapularis (Say) [Is]. Volatiles produced by defatted seed meals of the three plant species had strong bio-fumigation activity against ticks, but their effects varied among the three tick species. Toxicity of DFP seed meals was significantly different among the three tick species (no overlap of the 95% CI) with LD50 values of 0.056 g for Aa nymphs, 0.031 g for Dv nymphs, and 0.037 g for Is nymphs. Defatted Ls seed meals were more toxic to Dv (LD50 = 0.022 g) and Is (LD50 = 0.018 g) nymphs compared to Aa nymphs (LD50 = 0.035 g) while defatted PG seed meals were more toxic to Is nymphs (LD50 = 0.009 g) compared to Aa (LD50 = 0.048 g) and Dv (LD50 = 0.032 g) nymphs. This study is the first report to document that defatted Brassicaceae seed meals are a promising plant-based biofumigant for tick control that can be developed as a cheap, practical, and ecofriendly acaricide.

A review of acaricides and their resistance mechanisms in hard ticks and control alternatives with synergistic agents

Ticks are significant ectoparasites that transmit a variety of pathogens, leading to serious human and animal diseases, including Lyme disease, Rocky Mountain spotted fever, anaplasmosis, and many others. The emergence of acaricide resistance in hard ticks presents a formidable challenge for public health and livestock management, exacerbated by the increasing incidence of tick-borne diseases and associated economic losses, estimated at $20 billion annually in the livestock sector alone. This review examines the mechanisms underlying acaricide resistance, focusing on genetic mutations, metabolic detoxification processes, and behavioral adaptations in tick populations. We detail the role of commercial acaricides in tick control while emphasizing the adverse effects of their overuse, which contributes to the development of resistant strains. Innovative control strategies are explored, including using pesticide synergists that enhance the efficacy of existing acaricides by targeting the tick's phosphagen system. Additionally, this review highlights the importance of understanding the synergistic interactions between various control methods, including non-chemical approaches such as personal protection measures and landscape management. The review concludes by underscoring the urgent need for novel acaricides with new modes of action and implementing regular monitoring practices to combat acaricide resistance effectively. Addressing these challenges is vital for the sustainable management of tick populations and protecting public health and livestock productivity.

Biological Characteristics of the Cytochrome P 450 Family and the Mechanism of Terpinolene Metabolism in Hyalomma asiaticum (Acari: Ixodidae)

The CYP450 enzyme is a superfamily enzyme ubiquitously found in nearly all organisms, playing a vital role in the metabolism of both endogenous and exogenous compounds, and in biosynthesis. Unfortunately, an understanding of its classification, functions, expression characteristics, and other biological traits in Hyalomma asiaticum, a vector for Crimean-Congo Hemorrhagic Fever, as well as of the genes implicated in its natural product metabolism, is lacking. Towards this end, this study has identified 120 H. asiaticum CYP450 genes via transcriptome data in the face of a joint genome threat from terpinolene. The proteins these genes encode are of higher molecular weight, devoid of a signal peptide, and composed of unstable hydrophobic proteins principally containing 1-3 variable transmembrane regions. Phylogenetic evolution classifies these H. asiaticum CYP450 genes into four subfamilies. These genes all encompass complete CYP450 conserved domains, and five specific conserved motifs, albeit with different expression levels. GO and KEGG annotation findings suggest a widespread distribution of these CYP450 genes in many physiological systems, predominantly facilitating lipid metabolism, terpenoid compound metabolism, and polyketone compound metabolism, as well as cofactor and vitamin metabolism at a cellular level. Molecular docking results reveal a hydrophobic interaction between the ARG-103, ARG-104, LEU-106, PHE-109, and ILE-119 amino acid residues in CYP3A8, which is primarily expressed in the fat body, and terpinolene, with a notably up-regulated expression, with affinity = -5.6 kcal/mol. The conservation of these five key amino acid residues varies across 12 tick species, implying differences in terpinolene metabolism efficacy among various tick species. This study thereby fills an existing knowledge gap regarding the biological characteristics of H. asiaticum CYP450 genes and paves the way for further research into the functions of these particular genes.

Evolution of tick vaccinology

Ticks represent a major concern for society worldwide. Ticks are also difficult to control, and vaccines represent the most efficacious, safe, economically feasible and environmentally sustainable intervention. The evolution of tick vaccinology has been driven by multiple challenges such as (1) Ticks are difficult to control, (2) Vaccines control tick infestations by reducing ectoparasite fitness and reproduction, (3) Vaccine efficacy against multiple tick species, (4) Impact of tick strain genetic diversity on vaccine efficacy, (5) Antigen combination to improve vaccine efficacy, (6) Vaccine formulations and delivery platforms and (7) Combination of vaccines with transgenesis and paratransgenesis. Tick vaccine antigens evolved from organ protein extracts to recombinant proteins to chimera designed by vaccinomics and quantum vaccinomics. Future directions will advance in these areas together with other novel technologies such as multiomics, AI and Big Data, mRNA vaccines, microbiota-driven probiotics and vaccines, and combination of vaccines with other interventions in collaboration with regions with high incidence of tick infestations and tick-borne diseases for a personalized medicine approach.

Ixodiphagus hookeri (Hymenoptera: Encyrtidae) and Tick-Borne Pathogens in Ticks with Sympatric Occurrence (and Different Activities) in the Slovak Karst National Park (Slovakia), Central Europe

Ticks are involved in the transmission a plethora of pathogens. To effectively control ticks and mitigate the risks associated with tick-borne diseases, it is important to implement tick control measures. These may include the use of acaricides as well as the development and implementation of an alternative, environmentally friendly tick management program that include practices such as habitat modification or establishing biological control. Ixodiphagus hookeri Howard is a tick-specific parasitoid wasp that predates on several species of ixodid ticks and could contribute to the control of the tick population. This work aimed to detect the presence of parasitoid wasps in ticks (Ixodidae) using genetic approaches. Several tick species of the genera Ixodes, Haemaphysalis, and Dermacentor, with a sympatric occurrence in the Slovak Karst National Park in southeastern Slovakia, were screened for the presence of wasps of the genus Ixodiphagus. The DNA of the parasitoids was detected in four tick species from three genera. This work presents the first molecular detection of parasitoids in two Dermacentor tick species, as well as the first molecular identification of Ixodiphagus wasps in Ixodes ricinus and Haemaphysalis concinna ticks from the Karst area. In the given area, it was observed that I. ricinus and H. concinna ticks are hyper-parasitized by wasps. Moreover, it was observed that wasps here can parasitize several tick species, some of which are of less significance for human and animal health (as they transmit fewer pathogens).

Testing Efficacy of a Conserved Polypeptide from the Bm86 Protein against Rhipicephalus microplus in the Mexican Tropics

Rhipicephalus microplus economically impacts cattle production in tropical and subtropical countries. Application of acaricides constitutes the major control method; however, inadequate use has increased resistant tick populations, resulting in environmental and cattle product contamination. Anti-tick vaccines based on the Bm86 antigen are an environmentally friendly, safe, and economically sustainable alternative for controlling R. microplus infestations. Nevertheless, variable efficacy has been experienced against different geographic tick strains. Herein, we evaluated the efficacy of a conserved polypeptide Bm86 derived from a Mexican R. microplus strain previously characterized. Twelve cows were assigned to three experimental groups and immunized with three doses of the polypeptide Bm86 (pBm86), adjuvant/saline alone, and Bm86 antigen (control +), respectively. Specific IgG antibody levels were measured by ELISA and confirmed by Western blot. In addition, the reproductive performance of naturally infested R. microplus was also determined. The more affected parameter was the adult female tick number, with a reduction of 44% by the pBm86 compared to the controls (p < 0.05), showing a vaccine efficacy of 58%. Anti-pBm86 IgG antibodies were immunogenic and capable of recognizing the native Bm86 protein in the eggs, larvae, and guts of R. microplus. The negative correlation between antibody levels and the reduction of naturally tick-infested cattle suggested that the effect of the polypeptide Bm86 was attributed to the antibody response in immunized cattle. In conclusion, the polypeptide Bm86 showed a specific immune response in cattle and conferred protection against R. microplus in a Mexican tropical region. These findings support further experiments with this antigen to demonstrate its effectiveness as a regional vaccine.

The Role of Parasitoid Wasps, Ixodiphagus spp. (Hymenoptera: Encyrtidae), in Tick Control

Species of Ixodiphagus (Hymenoptera: Encyrtidae) are parasitoid wasps whose immature forms develop inside ixodid and argasid ticks (Acari: Ixodida). Following oviposition by adult female wasps into the idiosoma of ticks, larvae hatch and start feeding on their internal contents, eventually emerging as adult wasps from the body of the dead ticks. Species of Ixodiphagus have been reported as parasitoids of 21 species of ticks distributed across 7 genera. There are at least ten species described in the genus, with Ixodiphagus hookeri being the most studied as an agent for biological control of ticks. Although attempts of tick control by means of this parasitoid largely failed, in a small-scale study 150,000 specimens of I. hookeri were released over a 1-year period in a pasture where a small cattle population was kept, resulting in an overall reduction in the number of Amblyomma variegatum ticks per animal. This review discusses current scientific information about Ixodiphagus spp., focusing on the role of this parasitoid in the control of ticks. The interactions between these wasps and the ticks' population are also discussed, focusing on the many biological and logistical challenges, with limitations of this control method for reducing tick populations under natural conditions.

Desiccant Dusts, With and Without Bioactive Botanicals, Lethal to Rhipicephalus (Boophilus) microplus Canestrini (Ixodida: Ixodidae) in the Laboratory and on Cattle

The exotic southern cattle fever tick, Rhipicephalus (Boophilus) microplus (Canestrini) (Ixodida: Ixodidae), since its eradication from the United States in 1943, made a strong incursion into Texas, beginning 2016. The pest is arguably the most economically detrimental ectoparasite of cattle, Bos taurus L., worldwide. Current R. (B.) microplus control mostly relies on conventional synthetic acaricides to which the ixodid has been developing resistance. Our study demonstrates that commercially available desiccant dust products, with and without bioactive botanical additives, are strongly lethal, when applied dry, against larval R. (B.) microplus in the laboratory, and after being released on dust-treated cattle. Deadzone (renamed Celite 610, a diatomaceous earth product), Drione (silica gel + pyrethrins + piperonyl butoxide synergist), and EcoVia (silica gel + thyme oil), each prophylactically prevented larval R. (B.) microplus from attaching to and feeding on stanchioned calves. Desiccant dust-based products are less likely than conventional synthetic acaricides to decline in terms of efficacy as a result of ixodid resistance, and other desiccant dust advantages, including extended residual, flexibility in terms of application methods, environmental, animal, and human safety, and possible compatibility with organic, or 'green', production systems, are discussed. We anticipate that the desiccant dusts we evaluated, and others not included in this study (e.g., kaolin, perlite, and silica gel) will be effective when used with other control tactics in integrated pest management approaches for controlling R. (B.) microplus (and other ixodid species).