Residual and ovicidal efficacy of essential oil-based formulations in vitro against the donkey chewing louse Bovicola ocellatus.

Essential oils have shown good experimental potential as novel veterinary ectoparasiticides. However, if they are to be used as veterinary products, they must be available in formulations that are suitable for practical application against specific ectoparasites. Here, the efficacies of formulations containing 5% (v/v) lavender or tea tree oil, in combination with two emulsifiers [a surfactant, 5% (w/v) N-lauroylsarcosine sodium salt (SLS), and a soluble polymer, 5% (w/v) polyvinylpyrrolidone (PVP)], with or without 10% coconut oil, were tested in contact bioassays against the donkey chewing louse Bovicola ocellatus (Piaget) (Phthiraptera: Trichodectidae). Residual activity was quantified in open and closed containers; ovicidal efficacy was also examined. Exposure to either of 5% (v/v) lavender or tea tree oils with SLS or PVP resulted in louse mortality of 100%, but when coconut oil was included as an excipient, significantly lower efficacy was recorded. However, the formulations became significantly less effective after 2 h in open containers and 40 h in closed containers. The results confirm that the residual activity of essential oils is relatively transitory and the addition of 10% coconut oil does not prolong the period of insecticidal activity by slowing essential oil evaporation. Too short a period of residual activity is likely to be a significant impediment to the effective practical use of essential oils. However, unlike many synthetic pediculicides, the essential oils tested here were highly ovicidal, which suggests that prolonged residual activity may not be essential to kill newly hatched nymphs after treatment.

Essential oils in the management of the donkey louse, Bovicola ocellatus.

REASONS FOR PERFORMING STUDY: Chewing lice are widespread and clinically compromising parasites of livestock and equids. Their management is complicated by growing levels of resistance to commonly applied insecticides. Hence, the development of novel approaches to their control is of major clinical interest. OBJECTIVES: To assess the effects of incorporating the essential oils of tea tree and lavender into a grooming programme for populations of donkeys with natural infestations of Bovicola ocellatus in the UK and Ireland when louse populations were at their winter seasonal peak. STUDY DESIGN: In vivo field trial. METHODS: Suspensions of 5% (v/v) tea tree or lavender oil or an excipient only control were groomed into the coats of winter-housed donkeys (n = 198) on 2 occasions, 2 weeks apart. Louse counts were conducted before each application and 2 weeks later. RESULTS: After 2 applications, the groups groomed with lavender or tea tree oil suspensions had a significant reduction in louse intensity, with a mean decline in louse abundance of 78% (95% confidence interval 76-80%). Louse numbers in the groups groomed with excipient only either did not change or increased significantly. Donkey hair length had no effect on the decline in louse numbers. CONCLUSIONS: These results demonstrate that the inclusion of essential oil suspensions during grooming can be used to manage louse populations successfully.

Review article: Medical therapy for fistulizing Crohn's disease.

BACKGROUND: Fistulae will develop in approximately one-third of patients with Crohn's disease. With an expected spontaneous healing rate of only 10%, fistulizing Crohn's disease requires a comprehensive strategy with a medical and possible surgical approach. AIM: To summarize the current literature evaluating various medical options for treating patients with fistulizing Crohn's disease. METHODS: A literature review was conducted using PubMed (search terms: Crohn's disease and fistula) and manual search of references among the identified studies and relevant review papers to identify papers that present data on medical treatment of fistulizing Crohn's disease. RESULTS: The first line of medical therapy remains antibiotics (metronidazole and ciprofloxacin). Mercaptopurine and azathioprine are medications that are effective in treating fistulizing Crohn's disease. The current gold standard of medical treatment to induce and maintain remission for fistulizing Crohn's disease is infliximab. Used as induction therapy, infliximab produced a 62% clinical response, and a complete closure rate of 46%. A maintenance therapy trial demonstrated at 54 weeks, 46% of patients receiving infliximab continued to respond to treatment, compared with 23% in the placebo group (P = 0.001). CONCLUSION: Further research to find new therapies and to improve our existing medical treatment of fistulizing Crohn's disease is required.

Biologicals: principles, techniques and mechanisms of action.

Biological agents for the treatment of IBD are the result of both the explosion of knowledge precipitated by the techniques of molecular biology, and by the ability to use these same techniques to produce agents. Thus, there has been a greatly facilitated translation of basic knowledge into clinical therapy. An astounding number of biologic agents are currently in development for the treatment of IBD and other immune-mediated conditions. These include native microbiologic preparations isolated for beneficial properties, recombinant cytokines and anticytokines, monoclonal antibodies, antisense oligonucleotides, and in the future, somatic gene therapy. This work seeks to describe the principles and techniques of biologic agent development, as well as prime sites of action targeted by these agents. Recent advances in the techniques of molecular biology have made possible unprecedented progress in the treatment of many conditions. The techniques of molecular biology have provided new methods of drug discovery and at the same time have elucidated new therapeutic targets. Most notable has been the progress made in the treatment of chronic inflammatory and immune mediated conditions, including inflammatory bowel disease. This paper is intended to highlight the methodological principles behind biologic agents, methods of discovery and production, and to highlight potential therapeutic targets for these new agents.

Biological therapies for ulcerative colitis.

Biological therapies are being increasingly investigated for the treatment of inflammatory bowel disease. However, a great deal more study has been devoted to studies of Crohn's disease rather than ulcerative colitis. Ulcerative colitis, like Crohn's disease, represents an area of high clinical need, particularly for those patients who have disease inadequately responsive to corticosteroids and 5-aminosalicylates. The distinct anatomic distribution of inflammation in ulcerative colitis represents an important model for study, with the entire involved mucosa entirely accessible to endoscopy. In addition, there is an opportunity for local delivery of biologic agents in left-sided disease. Distinct pathogenetic factors in ulcerative colitis raise the possibility of therapies quite different from those used in Crohn's disease. This work describes the current state of knowledge regarding biological therapy in ulcerative colitis. The role of probiotic therapy, and studies of cytokine-directed therapies, therapies targeting adhesion and recruitment, and restitution and repair are described.