title: Effects of agricultural pesticides on the health of Rana pipiens frogs sampled from the field.
abstract: There is evidence that over the last 30 years, there have been mass declines in diverse geographic locations among amphibian populations due to disease outbreaks. Multiple causes have been suggested to explain this increase in disease incidence. Among these, climate changes, environmental pollution and reduced water quality are gaining attention. Indeed, some chemicals of environmental concerns are known to alter the immune system. It is possible that exposure to these pollutants could alter the immune system of anurans and render them more susceptible to different pathogens. In this study, we sampled Rana pipiens in five different sites near St. Lawrence River (Quebec, Canada) during the months of July and September in 2001. Two of these sites were protected areas, in which low levels of pesticides were detected, while the remaining three sites were located in areas with intensive corn and soybeans cultivations. Our results demonstrated that frogs living in agricultural regions are smaller in size and weight than frogs living in areas with lower levels of pesticides at both sampling times. Moreover, we have observed a significant decrease in the number of splenocytes (cellularity) and the phagocytic activity in frogs sampled in impacted sites. Taken together, these results suggest that frogs living in agricultural regions might be more vulnerable to infections and diseases through their smaller size and alteration of their immune system. Our results also contribute to the overall discussion on factors involved in amphibian declines.
authors.affiliation: INRS-Institut Armand-Frappier, 531 Boulevard des Prairies, Laval, QC, Canada H7V 1B7.
authors.forename: M S
authors.initials: MS
authors.lastname: Christin
authors.forename: L
authors.initials: L
authors.lastname: Ménard
authors.forename: I
authors.initials: I
authors.lastname: Giroux
authors.forename: D J
authors.initials: DJ
authors.lastname: Marcogliese
authors.forename: S
authors.initials: S
authors.lastname: Ruby
authors.forename: D
authors.initials: D
authors.lastname: Cyr
authors.forename: M
authors.initials: M
authors.lastname: Fournier
authors.forename: P
authors.initials: P
authors.lastname: Brousseau
mesh_terms: D000383:Agriculture; D000818:Animals; D049628:Body Size / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D002470:Cell Survival; D004784:Environmental Monitoring / Q000379:methods; D007121:Immunocompetence; D010575:Pesticides / Q000032:analysis / Q000633:toxicity*; D010587:Phagocytosis / Q000187:drug effects; D011792:Quebec; D011894:Rana pipiens / Q000276:immunology / Q000502:physiology*; D013154:Spleen / Q000166:cytology / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity
chemical_list: D010575:Pesticides; D014874:Water Pollutants, Chemical