The acute effects of single-dose orally administered doramectin, eprinomectin and selamectin on natural infections of Syphacia muris in rats

A rapid evidence assessment of the potential risk to the environment presented by active ingredients in the UK's most commonly sold companion animal parasiticides

A number of parasiticides are commercially available as companion animal treatments to protect against parasite infestation and are sold in large volumes. These treatments are not intended to enter the wider environment but may be washed off or excreted by treated animals and have ecotoxic impacts. A systematic literature review was conducted to identify the existing evidence for the toxicity of the six most used parasiticides in the UK: imidacloprid, fipronil, fluralaner, afoxolaner, selamectin, and flumethrin. A total of 17,207 published articles were screened, with 690 included in the final evidence synthesis. All parasiticides displayed higher toxicity towards invertebrates than vertebrates, enabling their use as companion animal treatments. Extensive evidence exists of ecotoxicity for imidacloprid and fipronil, but this focuses on exposure via agricultural use and is not representative of environmental exposure that results from use in companion animal treatments, especially in urban greenspace. Little to no evidence exists for the ecotoxicity of the remaining parasiticides. Despite heavy usage, there is currently insufficient evidence to understand the environmental risk posed by these veterinary treatments and further studies are urgently needed to quantify the levels and characterise the routes of environmental exposure, as well as identifying any resulting environmental harm.

Toxicological evaluations of betulinic acid and ursolic acid; common constituents of Houttuynia cordata used as an anthelmintic by the Naga tribes in North-east India

Background

Betulinic acid (BA) and ursolic acid (UA) are two major phytoconstituents of Houttuynia cordata Thunb., (Saururaceae) which is used as an anthelmintic in the traditional medicine system of the Nagas in Nagaland, India. This study evaluates their toxic potentials using rodent models (Swiss albino mice and Wistar rats) according to the OECD (Organization for Economic Cooperation and Development) guidelines. Acute and 28-day sub-acute oral toxicity studies were conducted, and evaluations were made based on biochemical, hematological, and histopathological observations.

Results

Acute oral toxicity study revealed the oral LD50 of both the test compounds to be > 2000 mg/kg in mice. Sub-acute administration of BA at 10 mg/kg body weight (b.w.) revealed a significant increase in serum glutamic oxaloacetic transaminase (SGOT), alkaline phosphatase (ALP), urea concentrations and eosinophil and lymphocyte counts in rats. Animals administered with 10 mg/kg b.w. UA revealed elevated neutrophil count, SGOT, ALP, and urea concentrations, whereas white blood cells (WBC), lymphocyte, and platelet counts were found to be low. Histopathological examinations of body organs revealed alterations in the architecture of the liver, kidney, and spleen tissues. Notably, all these alterations were recoverable as evident in the satellite group, indicating a recovering pattern from the toxic effects caused by the oral administration of these phytocompounds.

Conclusion

Although UA and BA possess several therapeutic properties, their long-term usage can cause mild toxicity in their users. This study also paves way for evaluating the optimum effective and safe dose of these phytocompounds.