Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Micropredators dictate occurrence of deadly amphibian disease

20.01.2014
A new study raises hope to successfully fight the chytrid amphibian pathogen

An international team of researchers has made important progress in understanding the distribution of the deadly amphibian chytrid pathogen.


Ibón Acherito in the Spanish Pyrenees. The researchers collected water samples there to better understand the current distribution of the pathogen Bd. The lake is on an altitude of about 1900 m in the Western Pyrenees and contains a large number of different amphibian species.
Photo: Dirk S. Schmeller/UFZ


The midwife toad (Alytes obstetricans) in the Pyrenees. Some populations of this species did resist Bd infection and the pattern of the resistances was a first indication for the researchers that interactions between Bd zoospores and microorganisms are worth investigating more deeply.
Photo: Dirk S. Schmeller/UFZ

In some regions, the deadly impact of the pathogen appears to be hampered by small predators, naturally occurring in freshwater bodies. These micropredators may efficiently reduce the number of free-swimming infectious stages (zoospores) by consuming them. This natural behavior will reduce the infection pressure on potential amphibian hosts and a goes a long way towards explaining the occurrence of chytridiomycosis, at least in temporal climatic regions.

These results were published in the renowned scientific journal Current Biology. The team of researchers state that their results raise the hope of successfully fighting chytridiomycosis, nowadays one of the most deadly wildlife diseases.

The entire class of the amphibians is greatly affected by the current wave of global extinctions. Although anthropogenic habitat alteration and fragmentation are the most important causes of amphibian biodiversity loss, mere conservation of amphibian habitats no longer guarantees amphibian survival. Indeed, the introduction of infectious diseases has been shown to drive amphibians to extinction even in seemingly pristine habitats. "The current amphibian decline is a disaster for ecosystems around the world" says Dr. Dirk S. Schmeller from the Helmholtz-Center for Environmental Research (UFZ) and the CNRS Unit Ecolab, and adds "Amphibians have key roles in freshwater ecosystems, and when they are gone, far going changes are unavoidable".

Chytridiomycosis is a disease which is devastating amphibians around the world. It is caused by the deadly chytrid skin fungus (Batrachochytrium dendrobatidis), or Bd, as scientists call it in short. Bd infects the skin of amphibians, which is an important respiratory organ for them, allowing them to breathe also in the water. "Bd needs to establish in a new environment and has usually a tight time window to infect a suitable host, either an adult amphibian or tadpoles and larvae of this species group", says veterinarian Prof. Dr. Frank Pasmans from the University of Ghent.

If Bd successfully establishes, infections will steadily increase and above a certain threshold, amphibians will start dying. In vulnerable species, local extinction can occur. In this manner many species have been lost, especially in Central America and tropical Australia. However, this worst case scenario did not occur in all populations of the Midwife Toad A. obstetricans in the Pyrenean Mountains, the main study area of the Biodiversa-project RACE, which intrigued scientists. They started a whole range of experiments, which took over three years to complete, to understand, which differences between different ponds and lakes of the Pyrenees could explain such a pattern. "The infected lakes and ponds did not look like the uninfected ones, neither in regard to the vegetation nor in regard to the geological characteristics" says Dirk S. Schmeller.

"When we brought in water from infected and uninfected sites, in some cases with help from donkeys, we saw clear differences in laboratory cultures of the pathogen, as well as in the infection dynamics." *provide a photo of donkeys carrying water* A series of additional experiments than clearly established that some microscopic aquatic predators, such as protozoans and rotifers, are capable of consuming large quantities of the infectious stage of Bd.

"The consumption of zoospores reduces the infection pressure for the whole population by reducing the number of infected tadpoles", says Mark Blooi from the University of Ghent.

Water bodies that do not support a diverse and abundant micropredator community, such as those that suffer from anthropogenic and environmental pressures, could lead to higher infection rates that lead to outbreaks of disease and amphibian population crashes. Dr. Adeline Loyau from the Helmholtz-Center for Environmental Research and the CNRS Unit Ecolab adds: "The big question to rapidly answer is, if by steering micropredator abundance and community composition, can we alleviate the impact of chytridiomycosis in natural amphibian populations? And if so, does this offer a realistic method for preservation of amphibians in Bd infected areas around the world." The work, conducted by an international research team financed by the Biodiversa-Project RACE, raises the hope for an effective biocontrol against the Chytrid fungus, one without the downsides associated with introducing nonnative biocontrol agents, such as the use of antifungal chemicals or release of nonnative skin bacteria into the environment, or the reliance of unpredictable environmental temperature to ‘‘cure'' infections. The study also contributes to a better understanding on how ecosystem health is linked to the establishment of pathogens in new environments, as only in healthy ecosystems the community of microorganisms might be able to consume zoospores effectively.

The results have been published in the January issue of Current Biology.

For photos and links see http://www.ufz.de/index.php?en=32370

Publication:
Dirk S. Schmeller, Mark Blooi, An Martel, Trenton W.J. Garner, Matthew C. Fisher, Frédéric Azemar, Frances C. Clare, Camille Leclerc, Lea Jäger, Michelle Guevara-Nieto, Adeline Loyau, Frank Pasmans: Microscopic Aquatic Predators Strongly Affect Infection Dynamics of a Globally Emerged Pathogen. Current Biology, 2014. http://dx.doi.org/10.1016/j.cub.2013.11.032

The work was conducted in the framework of the Biodiversa Project RACE and additionally financed by the Royal Zoological Society of Antwerp.

Further information:
Dr. Dirk S. Schmeller, Dr. Adeline Loyau
Helmholtz-Zentrum für Umweltforschung (UFZ)
phone: +49-(0)341-235-3282
http://www.ufz.de/index.php?en=12786
Prof. Dr. F. Pasmans/ Dr. Mark Blooi
Ghent University, Belgium
http://www.ugent.be/di/di05/nl/onderzoek/pasmans
Prof. Matthew C. Fisher
Imperial College London, Department of Infectious Disease Epidemiology
http://www1.imperial.ac.uk/medicine/people/matthew.fisher/
Dr. Trenton W. J. Garner
Institute of Zoology, Zoological Society of London
http://www.zsl.org/science/ioz-staff-students/garner,1093,AR.html
or
Tilo Arnhold, Susanne Hufe (UFZ press office)
phone: +49-(0)341-235-1635, -1630
http://www.ufz.de/index.php?en=640
Additional Links
RACE (Risk Assessment of Chytridiomycosis to European Amphibian Biodiversity):
https://www.bd-maps.eu/
https://www.bd-maps.eu/docs/race_factsheet.pdf
Wildlife diseases threaten Europe's biodiversity
RACE wrote a policy brief for IUCN that has now been published on the IUCN website: http://iucn.org/about/union/secretariat/offices/europe/?13819/Wildlife-diseases-threaten-Europes-biodiversity

At the Helmholtz Centre for Environmental Research (UFZ) scientists are interested in the wide-ranging causes and impacts of environmental change. They conduct research on water resources, biodiversity, the impacts of climate change and adaptation strategies, environmental and biotechnologies, bioenergy, the behaviour of chemicals in the environment and their effects on health, modelling and sociological issues. Their guiding motto: our research serves the sustainable use of natural resources and helps towards long-term food and livelihood security in the face of global change. The UFZ has over 1100 employees working in Leipzig, Halle und Magdeburg. It is funded by the federal government, as well as by the State of Saxony and Saxony Anhalt. http://www.ufz.de/

The Helmholtz Association contributes to finding solutions for large and pressing issues in society, science and the economy through excellence in the following six areas of research: energy, earth and the environment, health, key technologies, structure of matter, transport and aerospace. With almost 35,000 employees and coworkers in 18 research centres and an annual budget of approx. 3.8 billion Euros the Helmholtz Association is the largest scientific organization in Germany. Work is conducted in the tradition of the renowned natural scientist Hermann von Helmholtz (1821-1894). http://www.helmholtz.de/en/

Tilo Arnhold | UFZ News
Further information:
http://www.ufz.de/index.php?en=640
http://www.ufz.de/index.php?en=32370

More articles from Life Sciences:

nachricht A new potential biomarker for cancer imaging
05.02.2016 | Universiti Putra Malaysia (UPM)

nachricht NIH researchers identify striking genomic signature shared by 5 types of cancer
05.02.2016 | NIH/National Human Genome Research Institute

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Automated driving: Steering without limits

OmniSteer project to increase automobiles’ urban maneuverability begins with a € 3.4 million budget

Automobiles increase the mobility of their users. However, their maneuverability is pushed to the limit by cramped inner city conditions. Those who need to...

Im Focus: Microscopy: Nine at one blow

Advance in biomedical imaging: The University of Würzburg's Biocenter has enhanced fluorescence microscopy to label and visualise up to nine different cell structures simultaneously.

Fluorescence microscopy allows researchers to visualise biomolecules in cells. They label the molecules using fluorescent probes, excite them with light and...

Im Focus: NASA's ICESat-2 equipped with unique 3-D manufactured part

NASA's follow-on to the successful ICESat mission will employ a never-before-flown technique for determining the topography of ice sheets and the thickness of sea ice, but that won't be the only first for this mission.

Slated for launch in 2018, NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) also will carry a 3-D printed part made of polyetherketoneketone (PEKK),...

Im Focus: Sinking islands: Does the rise of sea level endanger the Takuu Atoll in the Pacific?

In the last decades, sea level has been rising continuously – about 3.3 mm per year. For reef islands such as the Maldives or the Marshall Islands a sinister picture is being painted evoking the demise of the island states and their cultures. Are the effects of sea-level rise already noticeable on reef islands? Scientists from the ZMT have now answered this question for the Takuu Atoll, a group of Pacific islands, located northeast of Papua New Guinea.

In the last decades, sea level has been rising continuously – about 3.3 mm per year. For reef islands such as the Maldives or the Marshall Islands a sinister...

Im Focus: Energy-saving minicomputers for the ‘Internet of Things’

The ‘Internet of Things’ is growing rapidly. Mobile phones, washing machines and the milk bottle in the fridge: the idea is that minicomputers connected to these will be able to process information, receive and send data. This requires electrical power. Transistors that are capable of switching information with a single electron use far less power than field effect transistors that are commonly used in computers. However, these innovative electronic switches do not yet work at room temperature. Scientists working on the new EU research project ‘Ions4Set’ intend to change this. The program will be launched on February 1. It is coordinated by the Helmholtz-Zentrum Dresden-Rossendorf (HZDR).

“Billions of tiny computers will in future communicate with each other via the Internet or locally. Yet power consumption currently remains a great obstacle”,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

AKL’16: Experience Laser Technology Live in Europe´s Largest Laser Application Center!

02.02.2016 | Event News

From intelligent knee braces to anti-theft backpacks

26.01.2016 | Event News

DATE 2016 Highlighting Automotive and Secure Systems

26.01.2016 | Event News

 
Latest News

A new potential biomarker for cancer imaging

05.02.2016 | Life Sciences

Graphene is strong, but is it tough?

05.02.2016 | Materials Sciences

Tiniest Particles Shrink Before Exploding When Hit With SLAC's X-ray Laser

05.02.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>