A non-lethal technique for detecting the chytrid fungus Batrachochytrium dendrobatidis on tadpoles

Richard W R Retallick, Verma Miera, Kathryn L. Richards, Kimberleigh J. Field, James Collins

Research output: Contribution to journalArticle

48 Scopus citations

Abstract

Batrachochytrium dendrobatidis (Bd) infection on post-metamorphic frogs and salamanders is commonly diagnosed using polymerase chain reaction (PCR) of skin scrapings taken with mildly abrasive swabs. The technique is sensitive, non-lethal, and repeatable for live animals. Tadpoles are generally not sampled by swabbing but are usually killed and their mouthparts excised to test for the pathogen. We evaluated a technique for non-lethal Bd diagnosis using quantitative PCR (qPCR) on swabs scraped over the mouthparts of live tadpoles. The sensitivity of non-lethal (swabbing) and lethal (removal of mouthparts) sampling was assessed using 150 Bd-infected Rana subaquavocalis tadpoles. Swabbing was consistently less sensitive than lethal sampling, but still detected Bd. Experimental Bd prevalence was 41.1% when estimated by destructively sampling mouthparts and 4.7 to 36.6% (mean = 21.4%) when estimated with swabs. Detection rates from swabbing varied with investigator and time since infection. The likelihood of detecting Bd-infected tadpoles was similar regardless of size and developmental stage. Swabbing mouthparts of live tadpoles is a feasible and effective survey technique for Bd, but, because it is less sensitive, more tadpoles must be sampled to estimate prevalence at a confidence level comparable to destructive sampling.

Original languageEnglish (US)
Pages (from-to)77-85
Number of pages9
JournalDiseases of Aquatic Organisms
Volume72
Issue number1
DOIs
StatePublished - Sep 14 2006

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Keywords

  • Batrachochytrium dendrobatidis
  • Chytridiomycosis
  • Detection
  • PCR
  • Tadpole
  • Technique

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science

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