In-vitro trials to ascertain sustained release efficacy of assembly pheromone micro particles for the control of brown dog tick, Rhipicephalus sanguineus.

Ticks are ubiquitous in nature and have considerable medical and veterinary importance. They act as vectors for a diverse array of pathogens affecting animals and humans. Rhipicephalus sanguineus is the most prevalent species infesting the dogs in Tamil Nadu. Control of this three-host tick mainly depends on the use of acaricides, with attendant problems of development of acaricidal resistance in ticks and possibility of drug residues. In the current study, pheromones were evaluated as an alternative substance for control of the dog tick. Optimal concentration of attractant sex pheromone (ASP), assembly pheromone (AP), and combination of both ASP and AP were encapsulated using calcium alginate beads for sustained release of pheromones. Bamboo sticky traps were designed as a platform to hold these pheromone encapsulated beads. Field trials were conducted using these pheromone lures as bait in the bamboo trap. Field trials revealed that AP encapsulated calcium alginate beads lured the maximum number of different stages of dog ticks. Thus, a bamboo trap with AP encapsulated calcium alginate beads can be used in integrated pest management along with other routine practices for control of dog tick in kennels. Statistical analysis by chi-square test revealed that there was a highly significant (p < 0.01) difference in the level of attraction between engorged and questing stages of ticks to the pheromones in the trap.

Solar tick trap with a pheromone lure – A stand-in approach for off-host control of Rhipicephalus sanguineus sensu lato ticks

Evaluations were made to assess the efficacy of assembly pheromone, attractant sex pheromone and the kairomone carbon dioxide in attracting the questing larval nymphal and adult stages of the brown ear dog tick, Rhipicephalus sanguineus. Ticks attracted to one location were killed using the acaricide deltamethrin. Initially, simulated field trials were conducted to observe the percentage of attraction of ticks from different distances. Tick lure comprising of carbon dioxide as kairomone and 2,6-dichlorophenol in combination with assembly pheromone and deltamethrin on a thermocol platform was prepared and field trials were conducted in the kennels of Blue Cross Society of India, Velachery, Chennai. The tick lure attracted larval, nymphal and adult stages of R. sanguineus ticks in and around the kennels. Observations were made after 24h of placing the tick lure. In simulated field out of the 50 ticks used for each distance trials, positive response was exhibited by a total number of 20 (40%), 17 (34%) and 14 (28%) ticks from 0.5, 1 and 1.5m, respectively. Field trials conducted revealed considerable attraction of larvae and nymph to the tick lure. Few adult ticks (2-5) were also lured to the pheromone impregnated filter paper disc.

The increasing incidence of tick-borne diseases and the growing resistance to conventional acaricides underscore the urgent need for innovative and sustainable tick management strategies. This study investigates the potential of assembly and sex pheromones for the control of larval stages of Rhipicephalus sanguineus, the brown dog tick, which poses significant health risks to dogs. The ticks were collected from various canine hosts in Thrissur, Kerala and subjected to Petri-dish bioassays using vapour patches impregnated with synthetic assembly pheromone (AP) and sex pheromone (SP), both individually and in combination. The efficacy of these semiochemicals was assessed based on the attraction and clustering behaviour of unfed larvae and partially fed adult ticks over a 24-hour period. Results demonstrated a significantly higher attraction to AP-impregnated patches, with notable efficacy observed in causing tick aggregation, particularly beyond 30 min of exposure. While SP also showed potential in attracting ticks, the combination of SP and AP did not result in a synergistic effect. The study highlights the potential of using semiochemicals as an environmentally sustainable alternative to traditional acaricides, highlighting their role in integrated pest management strategies Keywords: Rhipicephalus sanguineus, adenine, guanine, xanthine, 2,6-DCP, Petri-dish bioassay

Control of brown dog tick, Rhipicephalus sanguineus was attempted by utilizing sustained release preparations of synthetic analogues of assembly pheromones. The assembly pheromone, in defined ratio, was encapsulated using poly-ɛ-caprolactone by water-in-oil-in-water double emulsion solvent evaporation technique. In the in vitro bioassay, percent mortality with test microspheres was 95.6, 64 and 44 among the unfed larvae, unfed nymph and unfed adults respectively, 24 hours post-exposure. Field trials were carried out to evaluate the efficacy of microspheres in luring and killing environmental stages of R. sanguineus in dog houses/kennels. Engorged and unfed stages in the environment were found adhered and dead on the specially designed lure.

Object: The objective of the present study was to investigate the effect of various concentrations of natural and synthetic polymers on in vitro drug release from sustained release matrix tablets. Materials and method: HPMC K4M and acacia gum were used as synthetic (hydrophilic) and natural (hydrophobic) polymers respectively. Diclofenac sodium was used as a model drug to study the in vitro release profile. Matrix tablets of Diclofenac sodium were fabricated by varying the concentrations of both natural and synthetic polymer via direct compression method. Result: The results of all evaluation parameters of the matrix tablet were within the acceptable limit. A significant difference was observed on in vitro drug release due to difference in polymers and their concentration. HPMC K4M in the concentration of 7% w/v showed 88.20 ± 0.056% cumulative drug release at the end of 10 h while the same concentration of acacia showed 85.22% ± 0.045%. The release mechanism of matrix tablet followed zero order release kinetics. The finding of current investigation clearly indicates that the synthetic polymer was given a more sustained release profile than natural polymer on varied concentration. Conclusion: On comparing in vitro release of optimized formulation with marketed preparation, it was concluded that F3 was found to be more efficient and promising than marketed preparation.

The effect of an Assembly Pheromone – Deltamethrin complex (AP – D complex) on the larvae of five ixodid tick species viz. Rhipicephalus sanguineus, R. microplus, R. haemaphysaloides, Hyalomma marginatum and Haemaphysalis bispinosa, as well as the adults of R. sanguineus and R. microplus, was assessed by in vitro bioassays. All the larval as well as adult stages of ticks exposed to the AP – D complex were lured and killed within 24 hours of exposure, except H. bispinosa. Exposure to the AP – D complex for an hour resulted in 70%, 95%, 90%, 90%, 95% mortality of the larval stages of Rhipicephalus sanguineus, R. microplus, R. haemaphysaloides, H. bispinosa and H. marginatum respectively. No mortality was observed when the larval stages of the five tick species were exposed to AP alone (positive control). Exposure of adults to the AP – D complex for an hour resulted 92% and 90% mortality of R. microplus and R. sanguineus, respectively. Negligible mortality was recorded in adult ticks exposed to deltamethrin alone (Negative control), while no mortality was recorded when exposed only to AP (Positive control). Hence, the AP – D complex is better in luring and killing ticks than AP or D alone, regardless of the life stage. Our results suggest that the development of a sustained release AP – D complex device may be an effective means of controlling ticks in India.

Two combinations of assembly pheromone (AP), with and without hematin were utilized as a lure for the unfed larvae, nymph and adults of Rhipicephalussanguineus ticks. In-vitro trials were carried out with the AP encapsulated in calcium alginate beads and the response of different stages of ticks were recorded. Analysis of results revealed that rapid attraction was evident in unfed larvae exposed to beads containing AP without hematin. In case of unfed nymphal and adult stages, the presence or absence of hematin did not have any impact on arrestment.

In the current study, an attempt was made to encapsulate assembly pheromone using natural polymer, chitosan. Chitosan beads were prepared by incorporating assembly pheromone in conjunction with an acaricide, namely, deltamethrin. In the in vitro bioassay, the test beads attracted and killed 79 % of unfed larvae, 88 % of unfed nymphs and 61 % of unfed adults of the brown dog tick, Rhipicephalus sanguineus, in 24 h of exposure. Field trials were carried out to attract and kill the pre-parasitic environmental stages. The beads were dispersed onto specially designed devices and they were placed in infested kennels. The devices were observed after 10 days.

Tick sex pheromone (SP), assembly pheromone (AP) and their combination (SP + AP) were encapsulated in calcium alginate beads. In vitro bioassays, namely Petri dish and olfactometer assays, were employed to estimate the level of attraction of the various stages of Rhipicephalus sanguineus sensu lato, namely unfed and engorged (fed) larvae, nymphs, females, and males to the different pheromones. The study revealed that only the Petri dish assay was suitable to evaluate the response of larval stages whereas the olfactometer bioassay could also be used for evaluating the response of all other stages. Attraction to pheromone encapsulated calcium alginate beads of all tick stage was higher in the Petri dish assay than in the olfactometer assay.

A novel assembly pheromone trap for tick control in dog kennels

Five- to 7-week-old nymphs of the brown dog tick, Rhipicephalus sanguineus (Latreille), were exposed for 22 to 24 h to residues of acetone dilutions of 27 technical acaricides on disposable glass pipettes. Effectiveness of the compounds in killing ticks ranged from an LC50 of 0.000026% for propoxur to an LC50 of 0.053% for chlordane. The relative susceptibility (LC50) of the life stages of the brown dog tick, American dog tick, Dermacentor variabilis (Say), and the lone star tick, Amblyomma americanum (L.), to four acaricides was: larvae > nymphs > adults. Each analogous stage of the brown dog tick was generally more susceptible to permethrin, diazinon, and carbary1 than the same stage of the American dog tick or the lone star tick. Brown dog ticks were less susceptible to lindane, however, indicating the need for field data on each species in control programs in which acaricides are used.

The objective of this study was to develop and evaluate extended-release matrix tablets of Zopiclone, a hypnotic agent, utilizing both natural and synthetic polymers to achieve a controlled drug release profile. Zopiclone, known for its efficacy in treating insomnia, requires a formulation that provides sustained release to improve therapeutic outcomes and patient compliance. Matrix tablets were formulated using various combinations of natural polymers (Tragacanth and Lactose Bean gumm) and synthetic polymers Carbopol-941P, PVP K30. The tablets were prepared by the direct compression method and evaluated for various parameters, including tablet hardness, friability, drug content, and in vitro drug release. The extended-release characteristics were assessed using dissolution testing, where the impact of different polymer combinations on the drug release rate was analyzed. The results indicated that the use of synthetic polymers, particularly Carbopol-941P, provided a more controlled and consistent release profile compared to natural polymers alone. A combination of natural and synthetic polymers achieved an optimal balance, ensuring a sustained release of Zopiclone over an extended period. The optimized formulations demonstrated desirable release kinetics with a controlled drug release extending up to 12 hours, aligning with the therapeutic needs for extended release. These findings suggest that a judicious selection and combination of natural and synthetic polymers can effectively tailor the release profile of Zopiclone, enhancing its clinical efficacy and patient adherence.

We report that Rhipicephalus sanguineus (Ixodida: Ixodidae) faeces and its main component, guanine, act as assembly pheromones in short-range Petri plate bioassays. Arrestment activity in response to guanine was lower than that in response to natural excreta, indicating the presence of other active ingredients in natural excreta. The selective removal of appendages was used to establish the important roles played by the palps and the front pair of legs in the detection of the pheromone. Reaction to chemically pure guanine at varying concentrations occurred without a dose response; thus only the presence of guanine, not a critical amount, is required to induce assembly. Higher speed and intensity of clustering occurred at 33% relative humidity (RH). We conclude that female adults of R. sanguineus are more prone to assemble under dry conditions that match the arid microhabitats preferred by this species and that this tendency allows this tick to reside in human dwellings and dog kennels that maintain standards of comfort at 30-50% RH. Cleaning or removing tick excreta-covered surfaces on which ticks aggregate from within and around human dwellings may prove useful as a means of interfering with the establishment of off-host clusters of R. sanguineus.

Innovative way to dispense pheromones for off-host control of Rhipicephalus sanguineus sensu lato ticks