Frog Mortality Project

Typical frog die-off at garden pond The Frog Mortality Project was launched in May 1992 by Andrew Cunningham and Peter Bennett of the Institute of Zoology in London and Tom Langton of Herpetofauna Consultants International. Assisted by a small grant obtained from the Royal Society for the Prevention of Cruelty to Animals in 1992/93, a questionnaire survey was carried out on those responding to a national 
                                         Typical die off from early FMP investigations in 1992/93.

appeal for records of where dead or dying common/grass frogs and other animals were found in or around garden ponds in unusual circumstances. Work included collection of freshly dead specimens  by HCI, with Andrew Cunningham conducting post-mortems. The study found that unusual/mass mortality incidents of frogs were occurring in England to a much greater extent than had previously been appreciated and quickly led to Andrew  adding further work to the project as a part of his amphibian disease  PhD which was published in 2001.

 In 1993/1994 the RSPCA award a further grant of £15,000 to IOZ/HCI for FMP project work including a field investigation of around 15 grass/common frog mortality sites to investigate the health and apparent population trends at the sites where large numbers of frogs had died and post mortem investigations carried out. Work involved extensive testing of samples to investigate frog health and the nature of the disease and processes that might contribute to its spread within frog and other amphibian species. This research led to the discovery that Ranavirus infection was the major cause of unusual or mass mortality events in England. This was the first time that a Ranavirus of any kind had been found in the UK.

Frog Mortality In January 2002 The Frog Mortality Project formally closed although new studies and writing up of data continue as off-shoots from the project that had grown to become the most extensive disease study of any UK wild animal.

Health checks at study sites in the following years revealed the good news that some frogs had
 tissue and had recovered from the virus.


Froglife was appointed by the FMP to carry out secretarial support and received all public donations. These resulted from the high level of concern and interest from the public  towards frogs and charitable grant aid was obtained for the their important support role to the FMP. From 2002  Froglife undertook to continue the  role as a recipients for records of wild amphibian disease incidents and today continues this function. This function has already assisted another HCI sponsored NERC CASE studentship, to Trent Garner and Andrew Cunningham at Institute of Zoology, and to Richard Nichols at Queen Mary, University of London  where Amber Teacher has recently completed an investigation into aspects of the genetics of grass/common frogs exposed to ranavirus. The work detected reduced genetic diversity in populations where disease has caused large levels of die-off and where the frog population is recovering to some extent. The study  found the reduced genetic diversity within the major histocompatibility complex (a region of the genome involved in the immune response to viruses).  This implies that there is directional selection for more-resistant genotypes, indicating that the presence of ranavirus is affecting the population dynamics of the grass frog in Britain and that the species appears to be adapting to the presence of the pathogen.