Dicyclanil

Prophylactic and therapeutic efficacy of Australian-registered insecticide formulations against Old World screwworm (Chrysomya bezziana) infestation.[Pubmed:28749021]

Aust Vet J. 2017 Aug;95(8):265-272.

OBJECTIVE: To determine the prophylactic and therapeutic efficacy of Australian-registered insecticide formulations against Old World screwworm (OWS) myiases for potential use in screwworm containment and eradication programs. METHODS: The longevity of protection provided by six insecticidal formulations (subcutaneous ivermectin, doramectin and abamectin, a topically applied aqueous formulation of spinosad, ivermectin controlled-release capsule and a Dicyclanil spray-on formulation) was tested using implants of 1st-instar OWS larvae on Javanese thin-tail sheep. Therapeutic efficacy of four formulations (topical ivermectin, chlorfenvinphos/cypermethrin mixture, aerosol spinosad formulation and a formulation containing propetamphos and eucalyptus oil) was tested against 2- and 4-day-old OWS strikes. RESULTS: Both the ivermectin capsule and Dicyclanil spray-on formulation gave 100% protection against screwworm implants for the full 12 weeks of the study. Ivermectin, doramectin and abamectin administered SC all gave 100% protection at 3 days post-treatment, but at 2 weeks the protection had become incomplete. Spinosad dipping did not give complete protection at any time. All four therapeutic treatments gave complete resolution of 2-day-old strikes and topical ivermectin, spinosad and chlorfenvinphos/cypermethrin, but not the propetamphos/eucalyptus oil formulation, gave complete resolution of all 4-day-old strikes. CONCLUSION: Dicyclanil spray-on and ivermectin capsule formulations, both registered for use in sheep, but not for cattle or other livestock species, gave much longer protection against screwworm implants than the currently recommended SC ivermectin. Pre-emptive action to facilitate rapid deployment of these formulations in the event of a screwworm incursion is urgently needed.

C3H/He Mice as an Incompatible Cholangiocarcinoma Model by Clonorchis sinensis, Dicyclanil and N-Nitrosodimethylamine.[Pubmed:27417082]

Korean J Parasitol. 2016 Jun;54(3):281-9.

Clonorchis sinensis is a Group-I bio-carcinogen, associated with cholangiocarcinoma (CCA). The hamster is the only experimental model of C. sinensis-mediated CCA, but we oblige another animal model. The present study intended to develop a C. sinensis (Cs) mediated CCA model using C3H/He mice, co-stimulated with N-nitrosodimethyl-amine (NDMA) and Dicyclanil (DC). The mice were divided into 8 groups with different combinations of Cs, NDMA, and DC. Six months later the mice were sacrificed and subjected to gross and histopathological examination. The body weights were significantly reduced among the groups treated with 2 or more agents (eg. Cs+NDMA, Cs+DC, NDMA+DC, and Cs+NDMA+DC). In contrast, liver weight percentages to body weight were increased in above groups by 4.1% to 4.7%. A Change of the spleen weight was observed only in Cs+NDMA group. Though C. sinensis infection is evident from hyperplastic changes, only 1 worm was recovered. T wo mice, 1 from Cs and the other from Cs+DC group, showed mass forming lesions; 1 (281.2 mm(3)) from the Cs group was a hepatocellular adenoma and the other (280.6 mm(3)) from the Cs+DC group was a cystic mass (peliosis). Higher prevalence of gray-white nodules was observed in Cs group (42.9%) followed by Cs+NDMA+DC group (21.4%). The mice of the Cs+NDMA+DC group showed hyper-proliferation of the bile duct with fibrotic changes. No characteristic change for CCA was recognized in any of the groups. In conclusion, C3H/He mice produce no CCA but extensive fibrosis when they are challenged by Cs, NDMA, and DC together.

Effective control of a suspected cyromazine-resistant strain of Lucilia cuprina using commercial spray-on formulations of cyromazine or dicyclanil.[Pubmed:25168341]

Aust Vet J. 2014 Oct;92(10):376-80.

OBJECTIVE: To demonstrate the protection of Merino sheep from flystrike by Lucilia cuprina with cyromazine or Dicyclanil in an implant study and in the field. METHODS: In the implant study, sheep were treated with cyromazine or Dicyclanil and implanted with 1st-stage larvae from a newly isolated field strain of L. cuprina (CYR-LS) or a reference strain (DZR50), then assessed over 3 days and compared with the implants on untreated control sheep. In the field study, weaner lambs were treated with cyromazine or Dicyclanil and monitored weekly for flystrike over 18 weeks of grazing on the same farm from which the L. cuprina were isolated. RESULTS: Implant study: cyromazine (6%) provided effective protection against CYR-LS and DZR50 L. cuprina for a minimum of 13 and 10 weeks, respectively. Dicyclanil (5%) provided at least 18 weeks' protection against both strains. Field study: only 1 of 386 lambs in the cyromazine-treated group was struck in the first 14 weeks of the trial. No strikes occurred in the 198 sheep treated with Dicyclanil (5%). Rainfall, temperature and flytrap data indicated consistent fly pressure during the study. CONCLUSIONS: Based on the results of these studies, there was no evidence of reduced susceptibility to cyromazine or Dicyclanil and the periods of protection of sheep against L. cuprina were unaffected and consistent with the registered label claims.