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Defending Madagascar’s Frogs From Invading Fungus

Frog in Madagascar
Madagascar is known for rich amphibian diversity, including the Mantidactylus grandidieri pictured, which may be at risk from invasive fungus. (Photograph by Jonathan Kolby)

By Jonathan Kolby

It all started as an idea one afternoon seven years ago.  Having recently learned about the devastating amphibian chytrid fungus (Batrachochytrium dendrobatidis, or Bd) that was spreading globally and causing irreparable damage to the world’s amphibian biodiversity, I felt there must be something more I could personally do to help save the amazing amphibians of Madagascar.

Expansive field surveys had been performed around the island nation, which indicated the absence of Bd, a remarkable and important phenomenon, as dozens of countries had already been invaded.  The original catalyst and subsequent contemporary pathways of global Bd dispersal remain largely enigmatic, although the international trade in live amphibians for consumption, exotic pets, and research has been demonstrated to be a suitable vehicle of transcontinental spread in some instances.

Although amphibians are not commercially imported into Madagascar, I believed it was still only a matter of time before an outbreak of Bd would somehow occur, as was true for the island of Montserrat, where the iconic mountain chicken frog (Leptodactylus fallax) was nearly wiped to extinction following the unexpected arrival of Bd in 2009.  Judging from this and other similar outbreaks, I was concerned that any chance to help protect Madagascar’s amphibians from the alarming scope of decline and extinctions observed in Central America and Australia would be largely dependent on the earliest detection and intervention possible.

And that’s when the idea emerged.  Combining my varied expertise in amphibian field biology, wildlife disease dynamics, and international wildlife trade regulation, I saw an opportunity to complement traditional field surveillance activities with a rapid assessment project focusing on international wildlife trade disease surveillance, an avenue not previously considered as a tool to quickly develop information to help other countries identify Bd presence within their borders.

Swabbing a frog in Madagascar
Scientists swab a Mantidactylus majori frog for presence of chytrid fungus. (Photograph by Jonathan Kolby)

Annually, millions of live animals are shipped around the world, including frogs from Madagascar, which are destined for the pet trade in the U.S.  Shipments often contain hundreds of animals of various species collected from the wild from around the country.  I believed that surveillance for Bd within the international wildlife trade could greatly reduce the amount of time and scientific resources (both human and financial) necessary to perform field surveillance activities encompassing a comparable selection and volume of amphibians.

This is certainly not to say it should replace traditional field surveys, but that a targeted dual-tiered collaborative approach can offer significant long-term benefits by informing and guiding the most efficient investment of field resources if trade detection were to occur prior to field detection.

Looking for frogs in Madagascar
Researchers look for frogs in Madagascar. (Photograph by Jonathan Kolby)

Detecting the Disease

Little did I think that many years later, this idea and concept would ignite, catalyze a rapid response effort, and have me rush to Madagascar to help drive this national effort.  I sampled a single shipment of amphibians exported from Madagascar containing nearly 600 frogs and was astounded when results were recently obtained, confirming the presence of Bd in the skin swabs collected from three of these wild-collected amphibians.

With support from the National Geographic Society and the Columbus Zoo and Aquarium, I’ve been able to swiftly apply this urgent information and develop a rapid response program to evaluate the presence and distribution of Bd throughout the country.  I’m currently in my final week of a two-month expedition here in Madagascar to help decipher the origin of my trade surveillance results and determine whether Bd is indeed already present in the wild amphibian populations.

Over the past 50 days, my surveys have spanned hundreds of kilometers, included dozens of species, and assessed a multitude of habitats, in order to create a rapid expansive snapshot of disease distribution in the country.  Furthermore, I’m concurrently performing two methods of pathogen detection (swabbing and environmental water filtration) to assess pathogen presence with greater sensitivity and confidence than by traditional methods where only one technique is generally utilized at a location.

If detected, I will next investigate how this pathogen may have been introduced to Madagascar, and identify biosecurity opportunities to mitigate current and future disease dispersal events to reduce the potential impact on biodiversity.

Frog in Madagascar
Spinomantis aglavei. (Photograph by Jonathan Kolby)
Studying a stream in Madagascar
Jonathan Kolby collects a water sample. (Photograph by Devin Edmonds)

Lessons Learned 

The opportunity to help understand and mitigate the presence of amphibian disease while working to build local scientific capacity has been an astounding experience.  Along this journey, I have been exposed to the country’s astounding natural beauty, fascinating culture, and warm welcoming people and for this I feel quite privileged.  This fieldwork has been performed in collaboration with the Cellule d’Urgence Chytride Madagascar (Chytrid Emergency Cell), EcoHealth Alliance, and James Cook University.

I am grateful for the support of all who have assisted me in the field, including Falitiana Rabemananjara (Chytrid Emergency Cell), Devin Edmonds (Association Mitsinjo), Lance Woolaver and Rock William (Durrell Wildlife Conservation Trust Madagascar), and several Malagasy graduate students: Serge Ndriantsoa, Zo Faniry, and Sylviane Rakotozafy.  In particular, I am indebted to Sara Ramirez for her invaluable assistance in all facets of this investigation, from project conception to fieldwork.

Stream in Madagascar
(Photograph by Jonathan Kolby)

I eagerly await the results from the nearly 500 frogs and dozens of amphibian habitats we’ve sampled to determine if and where Bd is present and characterize the level of disease-associated threat now experienced by Malagasy amphibians.

Every great conservation challenge is followed by an opportunity for learning and innovation, and for this I remain optimistic that a strong international collaborative effort can still protect Madagascar’s amazing amphibians from the devastating spread of Bd.  A swift response is imperative to protect this wealth of biodiversity and the time to act is now!

Comments

  1. RANIVOARIVELO Soazara
    Madagascar
    August 23, 11:26 am

    Hi,
    I am very happy that you are interesting on saving frogs of Madagascar. Me too, I work in Isalo in order to save rainbow frogs and Mantella expectata, This is an ecotourism region and they are vulnerable from Bd contamination .
    I would like to start to study on it.

    Do you have any suggestion?

  2. Jonathan Kolby
    April 5, 12:40 pm

    Thanks Valerie! I hope that if Bd is found, it will be a strain with low virulence (such as an Asian Bd lineage?) so that we have some extra time to figure things out and develop a rapid action plan before declines might begin. And I fully agree–the absence of commercial amphibian importation almost certainly helps protect Madagascar, but since frogs are also found hitchhiking in non-amphibian cargo shipments (fresh produce, ornamental plants, etc.), it’s still possible they could slowly carry disease to the island… And yes, it’s also true that contaminated footwear from tourists and researchers pose another possible mode of chytrid dispersal, and biosecuirty efforts are very important to prevent accidental spread–this is why we scrubbed our field boots with bleach after sampling each different locality we visited.

  3. Valerie Clark
    South Africa
    April 5, 9:30 am

    Nice write up and photos, Jonathan. Let’s hope that there is no Bd in Malagasy frogs and that some Malagasy frog species could be looked at in the lab FAR away from Madagascar to see if they have chytrid resistance. Several frogs in South Africa have innate chytrid resistance, possibly due to skin chemicals and/or symbiotic bacteria. Perhaps natural defenses and general isolation of the island nation will keep the frogs of Madagascar safe. Frog legs, lab frogs, etc. are not imported into Madagascar and could be helping to keep it safe there. Cheers, Dr. Val http://www.iFrogs.net

  4. Susan Newman
    New Jersey, USA
    April 1, 9:13 am

    Great reporting and photos. Thanks you for all that you do to help frogs! – Susan