Infectious Disease and Worldwide Declines of Amphibian Populations, with Comments on Emerging Diseases in Coral Reef Organisms and in Humans

Endosulfan Exposure Disrupts Pheromonal Systems in the Red-Spotted Newt: A Mechanism for Subtle Effects of Environmental Chemicals

“…This study suggests that amphibian pheromonal systems could be one of the systems mediating subtle effects of environmental chemicals. In addition to local climate change, habitat fragmentation, infectious disease, and increased UV-B irradiation, increased use of environmental chemicals has been suggested to be one of the major factors underlying recent amphibian declines (1)(2)(3)(35)(36)(37)(38)(39). Therefore, disruption of amphibian pheromonal systems by such chemicals are possibly one other mechanism facilitating population declines because the system plays a critical role in the daily life of amphibians such as conspecific recognition, migration, social behavior, and reproduction.…”

Prevalence of Skeletal and Eye Malformations in Frogs From North-Central United States: Estimations Based on Collections From Randomly Selected Sites

“…Despite the fact that malformations appear to occur at scales that would not contribute significantly to population declines (Carey, 2000) the increased malformation prevalence and declining populations are occurring in the same time frame, which may be more than coincidental. Many population reductions can be associated with habitat destruction, degradation, fragmentation, and contamination (Reeder et al, 1998;Beasley et al, 2002) but others appear to be occurring in areas less affected by human influences (Berger et al, 1998).…”

“…Biotic stressors may cause amphibian malformations and declining populations directly (Blaustein et al, 1994;Ankley et al, 2000), or they may contribute indirectly by suppressing immune competence (Carey et al, 1999), or by increasing susceptibility to pathogens. Thus, the apparent concurrence of amphibian population declines and elevated malformation rates in the preceding 40 yr may be coincidental or the two phenomena may have responded to changing environmental conditions.…”

Antimicrobial Peptide Defenses in the Salamander, Ambystoma Tigrinum, Against Emerging Amphibian Pathogens

“…Ambystoma tigrinum is highly susceptible to ranavirus infection (Jancovich et al, 1997). The apparently recent emergence of both B. dendrobatidis and ranaviruses suggests that the immune defenses of susceptible species may not be effective against these newly emergent pathogens Carey, 2000;.…”

“…Batrachochytrium dendrobatidis has also been shown to infect adult tiger salamanders (Ambystoma tigrinum), although, in contrast to many frog species, A. tigrinum does not generally die from B. dendrobatidis infection (Davidson et al, 2003b). At the same time, another group of diseases caused by ranaviruses (Iridoviridae) have led to massive localized dieoffs of frogs and salamanders in North America and Europe (Carey, 2000;Daszak et al, 1999Daszak et al, , 2000Collins and Storfer, 2003). Ambystoma tigrinum is highly susceptible to ranavirus infection (Jancovich et al, 1997).…”