C. Sreekumar

A novel approach to control brown dog tick, Rhipicephalus sanguineus using sustained release poly-ɛ-caprolactone-pheromone microspheres

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.

A novel assembly pheromone trap for tick control in dog kennels

A novel ecofriendly sticky tick trap device for the control of dog tick Rhipicephalus sanguineus using gold nanoparticle assembly pheromone complex as a bait was developed. Assembly pheromones comprising of guanine, xanthine and adenine in the ratio of 25:1:1 was encapsulated in gold nanoparticle. The response of the different stages of unfed R. sanguineus ticks was evaluated using petridish bioassay. Statistical analysis was done using chi-square test. Petridish bioassay with unfed stages of R. sanguineus revealed that 100% of the larvae, nymph and adults were attracted to assembly pheromone nanogold complex within 24h. Of the 952 ticks trapped, ticks of different stages trapped in total by the baited sticky trap device, 543 (57%) were engorged and 409 (43%) were unfed ticks. The study revealed that assembly pheromone baited traps has the potential to control tick infestations in dog kennels.

Response of unfed stages of Rhipicephalussanguineus to subtle variations in the composition of assembly pheromone

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.

Polymerase chain reaction based detection of Toxoplasma gondii from lymph node aspirates of dogs

The purpose of the study was to detect DNA of Toxoplasma gondii in lymph node aspirates of dogs using amplification of SAG-2 gene fragment. Blood and lymph node aspirates were collected from 20 clinically ill dogs of different age groups. Lymph node aspirates were analysed with polymerase chain reaction (PCR). Two numbers of dogs were found to be positive by PCR. The PCR positive dogs showed modified direct agglutination test (MDAT) titre of 1:512 and 1:4,096. The remaining sera samples showed the titre value of less than 1:64 by MDAT and were also negative by PCR. This study indicates that lymph node aspirates could be an alternative ideal specimen for the detection of T. gondii.