A virulent strain of Newcastle Disease has been identified as the cause of a recent die-off of cormorants and gulls in some parts of Minnesota, and it remains an unconfirmed suspect in the deaths of cormorants on Lake Vermilion.

While the results of tests on the Lake Vermilion birds are not yet available, DNR officials are treating it as another outbreak of Newcastle.

According to Tom Rusch, with the Tower Area DNR, a total of 95 bird carcasses were recovered from Lake Vermilion’s Potato Island last Friday. Of those, a handful were gulls, but the vast majority were cormorants. All of the bird carcasses were burned at the site, and the DNR has posted the island closed to prevent the inadvertent spread of the highly contagious disease.

A viral avian disease, Newcastle rarely affects humans. When it does affect humans it generally causes a relatively mild pink eye. But the disease can spread to other birds, and is a particular concern to poultry growers. The virus also commonly affects other colonial waterfowl, such as pelicans.

Rusch said DNR officials used bio-hazard methods during their clean-up activities at Potato Island last week to insure that new areas weren’t contaminated as a result of their visit.

According to the DNR, outbreaks of Newcastle Disease typically kill young birds rather than adults, and that appears to have been the case on Potato Island.

Newcastle Disease is not new to Minnesota. The last virulent outbreak of this disease occurred in 2008, when about 2,400 birds died at eight different locations. State officials ensure that dead birds are buried or incinerated.

Cormorant and gull die-off occurred earlier this summer on Marsh Lake in Big Stone County and Wells Lake in Rice County and in recent days sick and dead cormorants have been discovered at Leech Lake in Cass County. Additionally, the National Wildlife Health Center in Madison, Wis., is conducting tests on dead cormorants, gulls and pelicans collected from Lake Vermilion and Lake of the Woods. The results of those tests should be available shortly.

To date, all dead birds have tested negative for the avian influenza virus.