CHYTRID FUNGUS (AN OVERVIEW) Fungi in the phylum Chytridiomycota are ubiquitous organisms that live in the water and soil. They act as primary degraders using substrate such as chitin, plant detritus, and keratin. Some are obligate parasites of fungi, algae, vascular plants rotifers, nematodes, or insects.

CHYTRID FUNGUS (AN OVERVIEW) Batrachochytrium dendrobatidis -- a chytrid fungus pathogenic to amphibians New genus and species original description published in March 1999 (Longcore et al., Mycologia 91(2):219-227) Isolated from captive blue poison dart frogs (Dendrobates azureus) at National Zoological Park Earlier hypothesized to be cause of declines in Central America and Australia (Berger et al., 1998 Proc. Nat’l. Acad. Sci. 95:9031-9036)

CHYTRID FUNGUS (AN OVERVIEW) Tadpoles appear uneffected by the fungus which infects only the keratinised mouthparts. Mechanisms by which cutaneous chytridomyccosis becomes a fatal infection Cutaneous respiration and osmoregulation impared Absorption of a toxic product produced by the fungus Allows pathways for other pathogenic infections

CHYTRID FUNGUS (AN OVERVIEW) In lab cultures sporangia developed fastest in 23º C (73.4 º F); slower growth occurred at 28 º C (82.4 º F); no growth observed at 29 º C (84.2 º F). Experimentally infected frogs become terminally ill 10-47 days after exposure. Infection occurs through waterborne zoospores that invade the superficial layers of the epidermis

Species affected in the Southwest Ambystomatidae Ambystoma tigrinum stebbinsi Hylidae Acris crepitans Hyla arenicolor Bufonidae Bufo boreas, B. canorus, B. microscaphus Ranidae Rana berlandieri, R. blairi, R. catesbeiana. R. chiricahuensis, R. subaquavocalis, R. tarahumarae, R. yavapaiensis

Rayleigh’s R = 21.45 z = 17.03 n = 27 P < 0.0001

Infected Not Infected

Not infected

20X

Infected 20X

Infected zoosporangia 100X

Infected zoosporangia 100X

Chytrid Fungus Management Assume all aquatic sites to be infected with chytrid fungus Long-term research sites should have a dedicated set of gear (clothing, nets, seines, etc.) used only at that site ALL gear used at individual sites should be cleaned of mud and edebris and disinfected between sites using 10% bleach solution or quatra-ammonia solution

Chytrid Fungus Management To reliably detect the presence of chytrid fungus at a site, a series of 3-5 tadpoles should be collected and preserved in 10% formalin. These tadpoles should be provided to NMDGF or AGFD herpetologists and should be processed and examined histologically for the presence of chytrid fungus. Federal and State permits are the responsibility of the collector or a representative of the sponsoring agency