11 April 2012

Fatal white-nose syndrome spreads through the USA

White-nose syndrome is a fungal disease that has killed more than 5.5 million bats in Northern America, with the infection being fatal  in almost every case. The disease was first recorded in New York in 2006 and despite the extensive efforts to control the disease since then, it has spread through 20 states in the USA and 4 Canadian provinces.

White-nose syndrome, caused by the fungus Geomyces destructans, is characterised by a white growth on a bats nose, ears, wings and tail. Other symptoms include weight loss and abnormal behaviour, such as diurnal activity.

The disease is caused by a common European fungus that oddly, doesn't kill bats in Europe. This has led scientists to believe that the fungus has either changed somehow in America, which gives it its fatal effects or that bats in Europe have a local immunity to the fungus that is not found in American populations, which protects them from the disease. It is hoped that if European bats have immunity to the fungus, it can lead to the formation of a vaccine for their cousins in America, helping to reduce the fatal effects of white-nose syndrome.

The main problem with the fungus is that it prefers to grow in dark, damp climates such as those found in caves. Obviously then, it easily spreads to any bats that are living in an infected cave and the fungus can wipe out entire colonies at a time. Catching the disease is particularly likely over winter when the bats are hibernating and sadly, many die in their sleep without even knowing that they were ever infected.

Recent studies in America have found that at least half of their bat species are at critical risk from the disease and face being wiped out. This is of great concern to the USA since resident bat populations are great controllers of pests and keep the populations of crop-damaging insects down, saving the US agriculture industry an estimated US$3.7 billion a year!

Thus, efforts to eradicate or mitigate the effects of the disease are underway and the US government plans to puts procedures in place in airports and in logistics companies that will hopefully slow or stop the spread of the disease, buying scientists more time to deal with it.

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