The Decline of the Sharp-Snouted Day Frog (Taudactylus acutirostris): The First Documented Case of Extinction by Infection in a Free-Ranging Wildlife Species? Lisa M. Schloegel, 1 Jean-Marc Hero, 2 Lee Berger, 3 Rick Speare, 3 Keith McDonald, 4 and Peter Daszak 1 1 Consortium for Conservation Medicine, 460 West 34th Street, New York, NY 10001 2 Griffith University Gold Coast, PMB 50, Gold Coast Mail Centre, Queensland 9726, Australia 3 James Cook University, Townsville, Queensland 4811, Australia 4 Queensland Parks and Wildlife Service, PO Box 975, Atherton 4883, Queensland, Australia Abstract: Infectious diseases are increasingly recognized as the cause of mass mortality events, population declines, and the local extirpation of wildlife species. In a number of cases, it has been hypothesized that pathogens have caused species extinctions in wildlife. However, there is only one definitively proven case of extinction by infection, and this was in a remnant captive population of a Polynesian tree snail. In this article, we review the potential involvement of infectious disease in the recent extinction of the sharp-snouted day frog Taudactylus acutirostris. Our review of available evidence suggests that a virulent pathogen of amphibians, Batrachochytrium dendrobatidis, caused a rapid, catastrophic decline of this species, from which it did not recover. We propose that this is the first case of extinction by infection of a free-ranging wildlife species where disease acted as both the proximate and ultimate cause of extinction. This highlights a probable underreporting of infectious disease as a cause of biodiversity loss historically and currently. Key words: amphibian decline, conservation medicine, chytridiomycosis, Batrachochytrium, Taudactylus, extinction INTRODUCTION The current extinction rate is estimated to be 100–1,000 times greater than the historical norm (Pimm et al., 1995). This is thought to be largely due to anthropogenic changes to the environment such as deforestation, species intro- duction, climate change, and others (Pimm et al., 1995; Thomas et al., 2004). A number of recent papers have highlighted the role of infectious disease in biodiversity loss, citing examples of disease-related mass mortalities and de- clines of wildlife populations (Woodroffe, 1999; Daszak et al., 2000; Dobson and Foufopoulos, 2001). These include the near extinction of the black-footed ferret, the local extinction of African wild dogs, and global population de- clines of amphibians (Thorne and Williams, 1988; Ginsberg et al., 1995). However, infectious diseases have been hypothesized to be the cause of extinction in only a few cases, e.g., Hawaiian birds, the thylacine, and indirectly the eelgrass limpet Lottia alveus (Guiler, 1961; Warner, 1968; Published online: February 11, 2006 Correspondence to: Peter Daszak, e-mail: daszak@conservationmedicine.org EcoHealth 3, 35–40, 2006 DOI: 10.1007/s10393-005-0012-6 Ó 2006 EcoHealth Journal Consortium