Wednesday, 20 October 2010
Interest and excitement is gathering around the concept of mitigating the lethal effects of Bd by either reducing the threshold burden of infection, or by completely removing Bd from key infected environments. The Zurich Bd mitigation workshop was the first global meeting to address potential mitigation strategies by sharing experience and data, and planning new approaches as well as collaborations. Approaches that were considered in the workshop varied from (i) manipulating pre-epizootic host density; (ii) bioaugmentation with Bd-cidal probiotic bacteria; (iii) antifungal approaches to treating hosts and habitats; (iv) immunisation using recently-discovered hyovirulent/avirulent strains of Bd, or other vaccine technologies; (v) biocontrol with copepods or other zoospore-predators and (vi) ex-situ captive breeding followed by re-introduction with individuals that have undergone 'assisted evolution'. From the meeting, it was clear that not only are there many approaches that can be used, but also several ongoing programs. Indeed, the title for this post is the slogan coined by Jaime Bosch for his new Santander 'Zero' mitigation grant focusing on removing Bd from Mallorca and Alytes muletensis. Indeed, perhaps the time has come to 'Shiver Bd; the mitigators are coming!'. We anticipate appropriate mugs and T-shirts to appear in CafePress soon so stay tuned.....
Wednesday, 6 October 2010
Bad news from Mat re: the Pyrenees, but what can be done about it? Recent news articles (Sierra Nevadas: http://www.nytimes.com/2010/10/05/science/05frog.html?_r=1&hpw Mallorca: http://www.nature.com/news/2010/100609/full/465680a.html ) show that some of us are trying some things out. Since mitigating any infectious diseases of wildlife is no small task, we need to share experiences, methods, project ideas and results at a global scale. Doug Woodhams and Benedikt Schmidt have organized a Bd mitigation workshop to run Oct 14/15 in Zuerich, Switzerland. Invitees include Cherie Briggs, Vance Vredenburg, Roland Knapp, Jaime Bosch, Mat Fisher, Reid Harris, Lisa Belden, Brian Gratwicke, Ross Alford, Erin Muths, Ursina Tobler, Leyla Davis, Corina Geiger, Sara Bell, Vicky Flechas, Louis Rollins-Smith and yours truly. Those of you not invited, don't worry, this is merely the first such meeting (and as such numbers had to be kept small) and the plan is to make a book of abstracts, notes and minutes available to all and sundry. This first meeting is global in nature, but herewith a challenge: why not organize your own, regional or even local, workshop on Bd mitigation (heck, on amphibian disease mitigation) to get the process moving for your amphibian assemblages threatened with disease? And remember to communicate the outcome of any meeting widely. Like on this blog, for instance.
Monday, 4 October 2010
Bd in the Pyrenees is concentrated into a group of lakes in the Vallee d'Aspe and Ossau. Within this region, one lake in the Ansabere valley, Lescun, has remained Bd free. Lac Lhurs supports a very large population of Alytes, and constitutes one of the main chytridiomycosis-free refuges for these amphibians. However, this has now changed and a low prevalence of infection (~15%) was detected for the first time in 2009. This year, 2010, infection with Bd has increased dramatically to 100% and the first chytridiomycosis mortalities were observed in September. We are still unclear about the mechanism that Bd uses to spread between lakes: Lac Lhurs is shielded from other valleys by a cirque of high peaks that may have limited vector-borne transmission via birds or other vertebrates. This may explain why the Lac remained uninfected in this heavily-infected region for so long. How did Bd arrive? As with so many other aspects of this enigmatic pathogens life-history, we do not know. However, we do know that this otherwise pristine population of amphibians now faces an uncertain future.
2010 has not been a good year for our sentinel species, Alytes, in the outbreak sites of the Pyrenees. The season was hard due to a very cold start - our dataloggers showed that the high altitude Lakes in the Vallee d'Aspe did not thaw until the 1st of June. The amphibians consequently had to hurry their development, and the emergence of Alytes in August was late, and characterised by very high mortality due to chytridiomycosis in several of our study lakes. Lac Arlet, on the GR10 pathway, was the scene of large die-offs and the Imperial College tream found over 350 mortalities in a single day. Die-offs here were still being recorded in early September, detected by local volunteers. Whether the cold early-season is linked to these unusually high mortalities is one of the questions that is currently being worked on.