High prevalences of hindlimb deformities were recorded in wild-caught green frogs (Rana clamitans), northern leopard frogs (Rana pipiens), American toads, (Bufo americanus), and bullfrogs (Rana catesbeiana) from agricultural sites exposed to pesticide runoff in the St. Lawrence River Valley of Quebec, Canada, between July and September 1992 and 1993. Of 853 metamorphosing anurans examined in 14 farmland habitats, 106 (12%; range 0 to 69%) had severe degrees of ectromelia and ectrodactyly, compared to only two (0.7%; range 0 to 7.7%) of 271 in 12 control sites. However, the variation in the proportion of deformities among sites was too large to conclude that there was a significant difference between control and pesticide-exposed habitats. Clinical signs varied and were characterized by segmental hypoplasia or agenesis of affected limbs. Conspicuous abnormalities interfered with swimming and hopping, and likely constituted a survival handicap. Because of circumstances and the frequency of these malformations in nine distinct habitats, and in three different species from one of our study sites, we propose a teratogenic action of exogenous factors. Despite the fact that many biotic and abiotic agents are potentially harmful to limb development, agricultural contaminants were suspected as primary aggressors. Thus, clinical examination and frequency of deformities in anurans might be an economical screening tool to assess ecosystem health and the presence of environmental contaminants.

This article has been cited by other articles:

				M. Solari, J. Paquin, P. Ducharme, and M. Boily P19 Neuronal Differentiation and Retinoic Acid Metabolism as Criteria to Investigate Atrazine, Nitrite, and Nitrate Developmental Toxicity Toxicol. Sci., January 1, 2010; 113(1): 116 - 126. [Abstract] [Full Text] [PDF]

				R. A. Heimeier, B. Das, D. R. Buchholz, and Y.-B. Shi The Xenoestrogen Bisphenol A Inhibits Postembryonic Vertebrate Development by Antagonizing Gene Regulation by Thyroid Hormone Endocrinology, June 1, 2009; 150(6): 2964 - 2973. [Abstract] [Full Text] [PDF]

				S.-i. Sugiyama, N. Shimada, H. Miyoshi, and K. Yamauchi Detection of Thyroid System-Disrupting Chemicals Using in Vitro and in Vivo Screening Assays in Xenopus laevis Toxicol. Sci., December 1, 2005; 88(2): 367 - 374. [Abstract] [Full Text] [PDF]

				P. H.G. Duijf, H. van Bokhoven, and H. G. Brunner Pathogenesis of split-hand/split-foot malformation Hum. Mol. Genet., April 2, 2003; 12(90001): R51 - 60. [Abstract] [Full Text] [PDF]

				J. M. Kiesecker From the Cover: Synergism between trematode infection and pesticide exposure: A link to amphibian limb deformities in nature? PNAS, July 23, 2002; 99(15): 9900 - 9904. [Abstract] [Full Text] [PDF]

				S. J. Degitz, P. A. Kosian, E. A. Makynen, K. M. Jensen, and G. T. Ankley Stage- and Species-Specific Developmental Toxicity of All-Trans Retinoic Acid in Four Native North American Ranids and Xenopus laevis Toxicol. Sci., October 1, 2000; 57(2): 264 - 274. [Abstract] [Full Text] [PDF]

				S. K. Sessions, R. A. Franssen, and V. L. Horner Morphological Clues from Multilegged Frogs: Are Retinoids to Blame? Science, April 30, 1999; 284(5415): 800 - 802. [Abstract] [Full Text]

				P. T. Johnson, K. B. Lunde, E. G. Ritchie, and A. E. Launer The Effect of Trematode Infection on Amphibian Limb Development and Survivorship Science, April 30, 1999; 284(5415): 802 - 804. [Abstract] [Full Text]

				T. Colborn and P. Short Pesticide use in the U.S. and policy implications: A focus on herbicides Toxicology and Industrial Health, February 1, 1999; 15(1-2): 241 - 276. [Abstract] [PDF]

				A. R. Blaustein, J. M. Kiesecker, D. P. Chivers, and R. G. Anthony Ambient UV-B radiation causes deformities in amphibian embryos PNAS, December 9, 1997; 94(25): 13735 - 13737. [Abstract] [Full Text] [PDF]