Page 570 - Veterinary Toxicology, Basic and Clinical Principles, 3rd Edition

Fipronil Chapter | 42 537

VetBooks.ir is 49 mg/kg (EPA, 1996). The sulfone metabolite is more CONCLUDING REMARKS
toxic than the parent compound to certain bird species.
AND FUTURE DIRECTIONS
This metabolite has shown a very high toxicity in game
birds and a moderate toxicity in waterfowl (EPA, 1996; Fipronil elicits neurotoxicity in mammals by inhibition of
Bobe et al., 1997). Fipronil is highly toxic to rainbow trout GABA A -gated chloride channels, producing hyperexcit-
ability of the CNS. Overdosage due to accidental inges-
and very highly toxic to bluegill sunfish with an LC 50
of 0.246 mg/L and 0.083 mg/L, respectively. Fipronil is tion often leads to serious toxicosis in dogs and cats.
moderately toxic to freshwater daphnids (LC 50 5 190 μg/L) There is no specific antidote for the toxicity of fipronil.
and crayfish (LC 50 5 14 20 μg/L), and is extremely toxic The manufacturer warns that the product may be harmful
to estuarine mysids (LC 50 5 0.14 μg/L). Fipronil was to debilitated, aged, pregnant or nursing animals and
reported to adversely affect development, fertility, and also states that fipronil must not be used on kittens less
reproduction of copepods (Amphiascus tenuiremis) than 12 weeks of age and on puppies less than 10 weeks
(Chandler et al., 2004). WHO classifies fipronil as a Class of age.
II moderately hazardous pesticide.

ACKNOWLEDGMENTS
DIAGNOSIS
Authors would like to thank Ms. Robin B. Doss for her assistance in
Diagnosis of a fipronil poisoning can be based on circum- preparation of this chapter.
stantial evidence, clinical manifestations and chemical
confirmation. Residue of fipronil or its metabolites (pre-
dominantly fipronil sulfone) can be detected in the blood, REFERENCES
tissue, fat, or hair using GC/MS, and can be used as a bio-
marker of fipronil exposure (Gupta and Milatovic, 2014). Aajoud, A., Ravanel, P., Tissut, M., 2003. Fipronil metabolism and dissi-
The long half-life (183 245 h) of fipronil in blood may pation in a simplified aquatic ecosystem. J. Agric. Food Chem. 51,
reflect its slow release from fat. Transferable residue of 1347 1352.
Anonymous, 2000. Fipronil. Pesticide News. 48, 20.
fipronil can be detected on a dog’s hair coat up to 4 weeks
Badgujar, P.C., Pawar, N.N., Chandratre, G.A., et al., 2015. Fipronil
after a single spot-on application (Fig. 42.2). In a recent
induced oxidative stress in kidney and brain of mice: protective
study, Huang et al. (2014) reported microRNA 155
effect of vitamin E and vitamin C. Pest Biochem. Physiol. 118,
(miR 155) in Zebrafish as a potential novel toxicological 10 18.
biomarker for fipronil exposure. Clinical signs and symp- Bobe, A., Coste, C.M., Cooper, J., 1997. Factors influencing the adsorp-
toms and pathological changes in liver are not specific, tion of fipronil on soils. J. Agric. Food Chem. 45, 4861 4965.
and are of little value in terms of toxicological biomarkers Bobe, A., Meallier, P., Copper, J., et al., 1998. Kinetics and mechanisms
and diagnosis. of abiotic degradation of fipronil. J. Agric. Food Chem. 46,
2834 2839.
Case, K.M., Vega, N.M., Gupta, R.C., et al., 2016. Safety evaluation of
TREATMENT Parastars Plus in dogs and assessment of transferable residue of
fipronil and cyphenothrin from dogs to humans. Front Vet. Med. 3,
There is no specific treatment for the toxicity of fipronil, 1 8.
and therefore treatment relies upon symptomatic and Chandler, G.T., Cary, T.L., Volz, D.C., et al., 2004. Fipronil affects on
supportive measures. If a dog or cat shows an adverse estuarine copepod (Amphiascus tenuiremis) development, fertility,
reaction to topical application of fipronil-containing and reproduction: a rapid life-cycle assay in 96-well microplate
ectoparasiticide (Frontline, Certifect or Parastar Plus), format. Environ. Toxicol. Chem. 23 (1), 117 124.
Cole, L.M., Nicholson, R., Casida, J.E., 1993. Action of phenylpyrazole
decontamination by washing at the site of application is
insecticides at the GABA-gated chloride channel. Pestic. Biochem.
advisable. The ingestion of any fipronil topical veteri-
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Cutler, S.L., 1998. Ectopic psoroptes cuniculi infestation in a pet rabbit.
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decontamination include gastric lavage, and administration de Medeiros, H.C., Constantin, J., Ashii-Iwamoto, E.L., et al., 2015.
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If hypersensitivity skin reactions occur after applica- Environmental Protection Agency, 1996. New Pesticide Fact Sheet.
tion of any topical product, the animals should be submit- PB96-181516. epa 737-F-96-005. U.S. EPA Office of Prevention,
ted for a bath with a noninsecticidal shampoo and Pesticides and Toxic Substances. May 1996.
symptomatic treatment (e.g., antihistamines, hydrocorti- Environmental Protection Agency, 1998. Office of Prevention, Pesticides
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sone or antibiotics).