An outbreak of a virus that can cause Newcastle Disease in birds may have been more limited in Voyageurs National Park than in other areas of Minnesota, according to Voyageurs National Park staff.
A Lake Kabetogama island supporting a double-crested cormorant colony that tested positive for the virus will not be closed, according to a news release issued by the park Tuesday.
Voyageurs National Park initiated a study investigating aspects of double-crested cormorant ecology in Lake Kabetogama in June. During the course of routine monitoring on July 21 and 22, National Park Service staff and collaborators encountered several cormorant chicks displaying behaviors similar to those of birds infected with Newcastle Disease reported in other parts of the state earlier that week.
At Voyageurs, a single chick was euthanized and submitted to the United State Geological Survey’s National Wildlife Health lab on July 22 for testing. Voyageurs National Park received test results on Aug. 12 from the Wildlife Health Lab confirming the presence of avian paramyxovirus-1, the virus that can cause Newcastle Disease in birds.
Tests for West Nile virus and avian influenza were negative, according to Voyageurs staff.
Newcastle Disease is not a major concern for humans. The disease can be transmitted via contaminated clothing and equipment, and infected birds can spread the virus through direct contact as well as through their feces and excretions, potentially resulting in conjunctivitis or mild influenza, or flu-like symptoms in humans.
Voyageurs National Park staff, after consulting with wildlife health officials from various state and federal agencies, have decided to not close access to the colony on Lake Kabetogama because of the limited risk to humans. The island supporting the cormorant colony is a small rock outcrop with no trees that receives almost no visitation by people because of the often strong smell produced by the bird feces present on the island.
Approximately 140-150 nesting pairs of cormorants were recorded on the colony this summer, compared to a high of 330 recorded in 2005. NPS staff and collaborators estimate that less than 25 percent of the chicks hatched this summer succumbed to the disease. Few adult cormorants or other birds inhabiting the island, such as ring-billed gulls and American white pelicans, were observed either dead or showing clinical symptoms of the disease, suggesting that the outbreak in Voyageurs National Park was more limited than in other areas of Minnesota.
For more information contact Steve Windels, VNP terrestrial ecologist, at 283-6692.