Chytridiomycosis in Atelopus varius - two sporangia containing numerous zoospores are visible

Chytridiomycosis is a fatal infectious disease that affects amphibians, caused by the chytrid - Batrachochytrium dendrobatidis . Chytridiomycosis has been linked to dramatic population declines or even extinctions in western North America, Central America, South America, and eastern Australia. There is no effective measure for control of the disease in wild populations. The disease is contributing to a worldwide decline in amphibian populations, a worldwide decline of species that apparently has affected 30% of the amphibian species of the world^[1]. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Binomial name (Linnaeus, 1771) The Costa Rican Variable Harlequin Toad (Atelopus varius), also known as the clown frog, is a neo-tropical true toad from the family Bufonidae (Crump 1986). ... A sporangium (pl. ... A motile asexual spore utilizing a flagellum for locomotion. ... This false-colored electron micrograph shows a malaria sporozoite migrating through the midgut epithelia. ... For other uses, see Amphibian (disambiguation). ... Orders Chytridiales Spizellomycetales Blastocladiales Monoblepharidales Neocallimasticales Chytridiomycota is a division of the Fungi kingdom and contains only one class, Chytridiomycetes. ... Batrachochytrium dendrobatidis is a recently discovered chytrid fungus that causes the amphibian disease chytridiomycosis. ... North America North America is a continent[1] in the Earths northern hemisphere and (chiefly) western hemisphere. ... For other uses, see Central America (disambiguation). ... South America South America is a continent crossed by the equator, with most of its area in the Southern Hemisphere. ... The Golden Toad of Monteverde, Costa Rica was among the first casualties of amphibian declines. ...

Although some declines have been credited to the fungus B. dendrobatidis, there are species that resist the infection and some reports have found that some populations can survive with a low level of persistence of the disease^[2]. In addition, most of the laboratory studies are not ecologically-relevant, which makes it difficult to take their conclusions to the field.

The first reports of infection of Batrachochytrium are from African clawed frogs of the genus Xenopus. Because Xenopus has been widely transported around the world, it is one potential vector for transmission of B. dendrobatidis. Other studies, however, suggest that B. dendrobatidis has been present in North and Central America for decades. Binomial name Xenopus laevis Daudin, 1802 The African clawed frog (Xenopus laevis, also known as platanna) is a species of South African aquatic frog of the genus Xenopus. ... Species Xenopus amieti (volcano clawed frog) Xenopus andrei (Andres clawed frog) Xenopus borealis (Kenyan clawed frog) Xenopus boumbaensis (Mawa clawed frog) Xenopus clivii (Eritrea clawed frog) Xenopus fraseri (Frasers clawed frog) Xenopus gilli (Cape clawed frog) Xenopus laevis (African clawed frog) Xenopus largeni Xenopus longipes (savannah clawed frog...

Laboratory studies suggest that the fungus performs poorly at high temperatures^[3], and that exposure of infected frogs to high temperatures will kill the fungus^[4]. This may explain why chytridiomycosis occurs primarily in cool climates.

Notes

1. ^ Stuart, S. N., J. S. Chanson, et al. (2004). "Status and trends of amphibian declines and extinctions worldwide." Science 306: 1783-1786.
2. ^ Retallick, R. W. R., H. McCallum, et al. (2004). "Endemic Infection of the Amphibian Chytrid Fungus in a Frog Community Post-Decline." PLoS Biology 2(11): e351.
3. ^ Berger, L., R. Speare, et al. (2004). "Effect of season and temperature on mortality in amphibians due to chytridiomycosis." Australian Veterinary Journal 82: 31-36.
4. ^ Woodhams, D. C., R. A. Alford, et al. (2003). "Emerging disease of amphibians cured by elevated body temperature." Diseases of aquatic organisms 55: 65-67.

External links

• Chytridiomycosis
• Wildlife Trade and Global Disease Emergence
• Origin of the amphibian chytrid fungus
• Main preventative management strategies for the Chytrid fungus
• Amphibian chytridiomycosis at Amphibian Diseases Home Page
• Impact of Chytrid fungus on frogs (Foundation for National Parks & Wildlife)
• 'Amphibian Ark' aims to save frogs from fungus