AVM and Chytrid fungus [News]

Undiagnosed Die-off, Avian - Argentina

ProMed-mail Posting
Archive Number: 20060202.0335
02-FEB-2006
Jack Woodall, Associate Editor ProMED-mail, woodall@promedmail.org

The original report of this outbreak, in our translation from the Spanish, reads:

"Technical personnel took soil and water samples, and they also collected dozens of dead birds, mainly ducks and eaglets, so that necropsies will be performed."

It is true that the dictionary translation of the Spanish word "aguiluchos" is "eaglets," but the list of birds of Argentina online in Spanish and English shows that the various birds called
"aguiluchos" are actually hawks, mostly of the genus _Buteo_, that feed on birds and small mammals; see: http://www.geocities.com/avesdeargentina/Listadeaves.html

Although botulism is certainly a possibility, this outbreak strikingly resembles those posted on ProMED from 1995 onwards of avian vacuolar myelinopathy (AVM), which also affects waterbirds and raptors in certain lakes in the USA (see refs. below). Those waterbirds had fed on a plant, hydrilla, introduced by the aquarium industry, which has escaped and now covers huge areas of many lakes in the USA. In some of those lakes, the hydrilla is covered with a
species of cyanobacterium that produces a neurotoxin. Plant-eating American coots and ducks die from the toxin and are scavenged by bald eagles, which die in their turn. Red-tailed hawks have been experimentally fed with affected coots, and have died with typical lesions, so a cyanobacterium/hydrilla/ duck/hawk food chain is possible.

If necropsies show the characteristic lesions of AVM in the brains of the birds in Argentina, investigators should look at the vegetation in the lake and see if any of the duck food-plants are infested with cyanobacteria.

Reference:
Wilde SB, Murphy TM, Hope CP, Habrun SK, Kempton J, Birrenkott A, Wiley F, Bowerman WW, Lewitus AJ. 2005. Avian vacuolar myelinopathy linked to exotic aquatic plants and a novel cyanobacterial species. Environ Toxicol. 2005 Jun; 20(3):348-53.


Pregnancy Test May Lie Behind Deadly Frog Fungus


Reuters
3 Feb 2006
Mary Marshall - tropical.forestry@btinternet.com

What do an old pregnancy test for women and a mysterious fungus that is killing frogs have in common?

Plenty, according to researchers at North-West University in South Africa, who believe they have traced the spread of the killer fungus to trade in the African clawed frog, used for decades in a bizarre but effective way of determining pregnancy.

"We think we have traced the origin of the spread of the amphibian chytrid fungus to the 'frog' pregnancy test for women, which was widely used from the 1930s to the 1960s," said Che Weldon, a zoologist at North-West University who has been researching the phenomenon.

That test involved taking the urine of a woman and injecting it into an African clawed frog. If the woman was pregnant the hormones in her urine would stimulate ovulation in the frog and it would spawn within a matter of hours.

The species was exported to labs around the world in huge quantities from South Africa from the 1930s -- the decade in which Weldon has traced the first recorded case of the fungus by examining preserved frogs in museum collections.

Some of the exported frogs were released or escaped into the wild where it is believed they spread the fungus, which can move quicklythr ough a water system and can jump from one frog species to another. (

>>>FULL ARTICLE