Are Outbreaks of Emerging Pathogens Correlated With Construction of Wetlands? Report 2: Amphibian Breeding and Disease Outbreaks During 2014-2015 And Possible Correlates With Environmental Variables

A study of wetlands near the Intercounty Connector construction site (now a toll facility – MD 200) in Maryland, found that an emerging pathogen known as Ranavirus was having a significant impact on at least two species of amphibians as well as on Box Turtle populations. Of special interest was the finding that Ranavirus outbreaks were found in two wetlands constructed by Montgomery County Parks as part of habitat restoration procedures. This supports the findings of earlier researchers who suggested that Ranavirus outbreaks might be associated with the construction of wetlands. Such newly constructed wetlands sites may be a focal point for infection due to rapid colonization by susceptible species, such as Wood Frogs or Spotted Salamanders. These sites might also be used as foraging sites by species thought to be carriers of Ranavirus, such as Bullfrogs or Green Frogs. In order to understand how Ranavirus is affecting amphibian and reptile populations in the Northeast U.S. and to determine the link, if any, between construction of wetlands and Ranavirus outbreaks, Towson University examined 60 Maryland Department of Transportation State Highway Administration (SHA) created wetlands. Ultimately, 16 sites in 2014 and 22 in 2015 were selected for focal monitoring. Six sites (37.5%) had some level of die offs in 2014 compared with eight sites (36.3%) in 2015. These rates were slightly higher than those seen in a study of non-SHA wetlands in Maryland. Due to quality control issues, Polymerase Chain Reaction (PCR) testing was considered reliable only in 2015. PCR testing in 2015 found the presence of Ranavirus in all die-off sites sampled and 54% of SHA wetlands sampled. Levels of Ranavirus in die off sites were extremely high, on the order of hundreds of millions of copies of the virus. These data suggest a possible link between environmental variables and presence of Ranavirus infection, but a larger sample size of ponds would provide a more robust test of this association.


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Appendices; Figures; Maps; Photos; References; Tables;
  • Pagination: 35p

Subject/Index Terms

Filing Info

  • Accession Number: 01618150
  • Record Type: Publication
  • Report/Paper Numbers: MD-15-SHA-TU-1-04
  • Contract Numbers: SP509B4N
  • Created Date: Nov 30 2016 2:53PM