Rapid Response to Evaluate the Presence of Amphibian Chytrid Fungus (Batrachochytrium dendrobatidis) and Ranavirus in Wild Amphibian Populations in Madagascar

Abstract

We performed a rapid response investigation to evaluate the presence and distribution of amphibian pathogens in Madagascar following our identification of amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) and ranavirus in commercially exported amphibians. This targeted risk-based field surveillance program was conducted from February to April 2014 encompassing 12 regions and 47 survey sites. We simultaneously collected amphibian and environmental samples to increase survey sensitivity and performed sampling both in wilderness areas and commercial amphibian trade facilities. Bd was not detected in any of 508 amphibian skin swabs or 68 water filter samples, suggesting pathogen prevalence was below 0.8%, with 95% confidence during our visit. Ranavirus was detected in 5 of 97 amphibians, including one adult Mantidactylus cowanii and three unidentified larvae from Ranomafana National Park, and one adult Mantidactylus mocquardi from Ankaratra. Ranavirus was also detected in water samples collected from two commercial amphibian export facilities. We also provide the first report of an amphibian mass-mortality event observed in wild amphibians in Madagascar. Although neither Bd nor ranavirus appeared widespread in Madagascar during this investigation, additional health surveys are required to disentangle potential seasonal variations in pathogen abundance and detectability from actual changes in pathogen distribution and rates of spread. Accordingly, our results should be conservatively interpreted until a comparable survey effort during winter months has been performed. It is imperative that biosecurity practices be immediately adopted to limit the unintentional increased spread of disease through the movement of contaminated equipment or direct disposal of contaminated material from wildlife trade facilities. The presence of potentially introduced strains of ranaviruses suggests that Madagascar's reptile species might also be threatened by disease. Standardized population monitoring of key amphibian and reptile species should be established with urgency to enable early detection of potential impacts of disease emergence in this global biodiversity hotspot.

Xenopus-FV3 host-pathogen interactions and immune evasion

“…Over the last 50 years, infections caused by ranaviruses ( Iridoviridae ) in most part of the world have markedly increased in prevalence as well as in the range of species infected (Chinchar et al, 2009; Duffus et al, 2015; Kik et al, 2011; Kolby et al, 2014; Kolby et al, 2015; Price et al, 2014). Emerging infectious diseases caused by ranavirus are not only alarming for biodiversity and aquaculture, but also poses fundamental issues related to the evolution of host/pathogen interactions (Chen and Robert, 2012; Collins; Daszak et al, 1999; Gray et al, 2009; Robert and Gregory Chinchar, 2012).…”

Combining old and new evidence to increase the known biodiversity value of the Sahamalaza Peninsula, Northwest Madagascar

“…Climatic change is likely to intensify the effects of Madagascar's habitat loss (Raxworthy et al, 2008;Huey et al, 2009;Walls et al, 2013), as will the recent discovery of potentially emergent infectious pathogens (Bletz et al, 2015a(Bletz et al, , 2015bKolby et al, 2015), and the introduction of invasive species (Andreone et al, 2014;Crottini et al, 2014;Kolby et al, 2014;.…”

A proposal for ethical research conduct in Madagascar

“…This increased risks of contamination and spreading of diseases, for human beings as with influenza epidemics (bird flu) but also for biodiversity as for example the transmission of pathogens to frogs (e.g., Phillott et al 2010, Kolby et al 2015 or bats (Blehert 2012).…”

“…Researchers should use established protocols to avoid transmission of pathogens to animals (e.g., Phillott et al 2010, Blehert 2012, Kolby et al 2015. Care should be taken to prevent any biopiracy of indigenous knowledge and biological products that might otherwise occur through removing indigenous rights for maximizing economic profits (e.g., Efferth et al 2016, application of Nagoya Protocol).…”