ITHACA, NY -- Crusty eyes, seizures, and paralysis are among some of the strange symptoms that have recently plagued and even killed some songbirds in several eastern states across the United States.
Although this deadly phenomenon has reached neighboring states such as Pennsylvania and New Jersey, New York has yet to report a case of the mysterious outbreak. While remaining vigilant about the situation and researching causes, experts at Cornell’s Lab of Ornithology and the College of Veterinary Medicine are not overly alarmed, especially as cases taper off and songbird populations remain stable.
The Cornell Wildlife Health Lab has been monitoring the evolving situation. The lab, housed under the Cornell University College of Veterinary Medicine, was created in 2010 with the Department of Environmental Conservation in order to develop a wildlife disease surveillance program. The lab works with a network of partners on the local, state, and national level, and engages with the public in order to promote the health of wildlife populations.
Through their highly connected communication channels, the lab received the first reports of cases at the end of May from partners in Maryland, Pennsylvania, and Washington, DC. Researchers in these states began testing, but were unable to come up with any conclusive results about the outbreak.
“Over the course of weeks, no one was finding anything infectious,” Elizabeth Bunting, Senior Extension Associate at the Cornell Wildlife Health Lab said. “They did a lot of testing but could not come up with any disease process, and the rehabilitators were telling us they were trying antibiotics and things like that, but they did not have great effectiveness.”
Bunting said that the outbreak exhibits similar symptoms to mycoplasma, a bacterial infection that commonly afflicts finches, causing swollen eyes. However, this disease lacks the neurological components that accompany the unknown illness. Labs across the nation have worked to rule out many other possibilities including salmonella, avian influenza, and the West Nile virus.
In just the past few weeks, the Wildlife Lab has received widespread news of declining cases and dropping mortality rates.
“Information coming out of the National Wildlife Health Center and some of the other states said that the cases were declining all of a sudden,” Bunton said. “That would not be typical of an infectious disease outbreak. You wouldn't expect an infectious disease to just spontaneously go away.”
This sudden decline lends support to the tentative hypothesis regarding a cause of the outbreak. The most recent working theory is that the outbreak is related to the emergence of the cicadas this year — the geographic distribution and the timing of the undetermined songbird illness directly coincides with the arrival of the cicadas.
The cicadas emerged in Washington, DC and eleven other states: Delaware, Indiana, Ohio, Pennsylvania, New Jersey, Maryland, West Virginia, Virginia, Tennessee, Florida, and Kentucky in mid May. Birds in these states started showing the unusual symptoms about a week later.
“The distribution of states where this spontaneously popped up was an exact match for the cicada emergence map, and it is a very strange distribution of states for this kind of outbreak,” Bunton said. “It was Virginia, West Virginia, Maryland, Delaware, New Jersey, Pennsylvania, and then it moved over to Tennessee, Kentucky, Ohio, Indiana but it completely skipped New York and the rest of New England. That is an exact replica of the cicada map.”
Researchers such as Bunton believe that the ingestion of the cicadas could have had toxic effects on the birds. It is possible that individuals sprayed the cicadas with pesticides, which have chemicals that affect the brains of birds and could have caused the neurological symptoms. Cicadas also carry fungi that can produce toxins when ingested which could have also produced the illness in the birds.
The decline in cases corresponds with the retreat of the cicadas. Although researchers will continue to monitor the situation, Bunton expressed that the outbreak should not be a cause of alarm. The diminishing outbreak does not pose any safety threats to humans, nor does it threaten the stability of the various songbird species.
“This seems not to have been something that was going to travel and have a really significant impact,” Bunton said. “But we are very thankful that people are paying attention. This is exactly what we need to have happen when we see things in wildlife that are concerning.”
Faith Fisher is a reporter from The Cornell Daily Sun working on The Sun's inaugural summer fellowship at The Ithaca Times.