A team of scientists in the United Kingdom has found a new and highly contagious disease for tadpoles among a wide range of frog populations in different parts of the world. The new discovery offers a potential explanation on the various threats that the species face that have led to their decline worldwide.
In a study featured in the Proceedings of the National Academy of Sciences journal, researchers from the Natural History Museum and the University of Exeter made use of molecular procedures to identify potentially infectious agents in tadpoles of frogs.
They discovered that tadpoles collected from six different countries in three continents tested positive for protists, which are single celled microorganisms with complex cell structures. These microbes have the ability to store DNA inside a nucleus, similar to cells of humans.
Protists were present in the liver of tadpoles that came from temperate and tropical locations, as well as in all the other continents tested during the study. The highly contagious agent is believed to be a distant cousin of the Perkinsea sp., another species of marine parasite that is commonly found in algae and other animals.
Exeter professor Thomas Richards, one of the researchers involved in the study, explained that the populations of frogs from around the world are experiencing a critical declines in numbers and infectious illnesses have been shown to be a major factor.
He said that their study has helped identify a group of microorganisms that infect the liver of tadpoles from different populations of frogs around the world.
Richards added that they need to determine if the novel microorganism, which is distantly related to parasites in oysters, causes serious illness to frogs, and if it is the one contributing to the declines of populations in the world.
Amphibians, such as frogs, are considered to be one of the most endangered animal groups on the planet. In 2008, around 32 percent of species of frogs were named as either threatened or extinct, while around 42 percent were identified in sharp decline.
Environmental experts believe that declining populations of amphibians and other species of animals point to an impending mass extinction event, which would be the sixth one in the history of the world.
The high rate of extinction observed in recent years has begun to rival the decline and mass die-off of the dinosaurs in only 250 years.
Photo: Trish Hartmann | Flickr
