Jennifer Toussaint, Arlington, Virginia's chief of animal control, can't forget the four newborn blue jays. Residents were concerned enough to send the fledglings to her clinic just outside of Washington, D.C., in late May.

Toussaint claims that each was fat, suggesting that "their parents had done an excellent job caring for them." But, on the other hand, the birds were sluggish, unable to maintain their equilibrium, and partially blinded by crusty, oozing patches that had developed over their eyes.

Mysterious Fatal Sickness

According to Toussaint and her team, the jays were the latest victims of a mysterious fatal sickness that had arisen in their region just a few weeks before and had already killed many wild birds. They killed the jays because there was no recognized therapy. Toussaint recalls how terrible it was to feel helpless.

Hundreds of cases in at least a dozen species of birds in nine states since May. Scientists have ruled out Salmonella bacteria, numerous virus families, and Trichomonas parasites as causes. Experts are looking for evidence of a cause in bird corpses and the environment.

"Knowing what isn't the cause is just as important as knowing what is," Toussaint adds. But it also means that wildlife epidemiologist David Stallknecht, director of the Southeastern Cooperative Wildlife Disease Study at the University of Georgia, Athens, which is engaged in the project, adds, "We're still scratching our brains on this one."

Hundreds of thousands of people have reported ill or dead birds in Virginia. Most cases involve grackles, blue jays, American robins, and European starlings. Young birds seem to be particularly vulnerable. Some species are more susceptible than others. Researchers are beginning to understand the outbreak.

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Incoming Data

According to Allisyn-Marie Gillet, Indiana's state ornithologist, those demographics might alter as more data comes in, particularly from rural areas where few observations have been made thus far.

But, according to experts, the epidemic does not appear to represent a significant danger to bird populations at this time. Still, they're keeping an eye on it to see if it spreads farther; instances of sick birds have been reported as far west as Indiana and Kentucky and as far north as Pennsylvania.

Cicada Disease

Cicadas are eaten by birds, causing some scientists to speculate that the outbreak may be connected to the insects. Massospora, a type of fungus that infects cicada broods, may also play a role. The cicadas appear to be innocent.

Mass Deaths

Bird extinctions are not unusual, especially among species that form dense flocks or congregate at feeders. Researchers have monitored outbreaks of West Nile virus, avian influenza, and Salmonella over the last few decades. The study was published in the American Journal of Infectious Diseases.

Other Possible Causes

According to the July 2 announcement, several of those suspects have been ruled out in this instance. However, experts are still looking at other options. They're utilizing electron microscopy to look for telltale damage in tissues and a battery of tests to look for suspicious bacteria, viruses, parasites, and chemical pollutants, for example.

The number of birds being brought to rehab facilities in Virginia is starting to decline. Officials urge bird enthusiasts to take precautions to prevent the spread of any disease until the epidemic is finished. The says there are signs that the outbreak is slowing down, but it's still a concern.

Also Read: 'Freak Weather' Blamed for Mysterious Disappearance of Thousands of Pigeons in UK

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