Conjunctivitis listed by USGS as diagnosis for many birds that died during the 2021 bird mortality event in Maryland and Washington

Conjunctivitis (not otherwise specified) is listed as the event diagnosis for many birds that died in Maryland and Washington, D.C. in the spring and summer of 2021 – this according to the U.S. Geological Survey (USGS) Wildlife Health Information Sharing Partnership Event Report System (WHISPers).

The birds that reflect the diagnosis were also listed as having been tested by the USGS National Wildlife Heath Center.

According to WHISPers, these birds, “mostly young,” were grackles, European starlings and blue jays.

Other dead birds from Washington and Maryland which USGS didn’t indicate were tested reflect a diagnosis of “Conjunctivitis (not otherwise specified) suspect” or “Not assessed.”

In other states that reported dead birds, such as Virginia and West Virginia, the diagnosis is listed as pending.

The diagnosis for birds from Kentucky is “bacterial infection (not otherwise specified) suspect” and “conjunctivitis (not otherwise specified) suspect.”

According to Red Creek Wildlife Center, “Avian conjunctivitis is an eye infection that can inflict many species of songbird but is most often seen in house finches. The bacteria affect the conjunctiva, the membrane surrounding the eyes, causing the tissue to swell and become irritated. As the infection spreads, the bird can become completely blind.”

Many of the birds in the mass mortality event of 2021 exhibited neurological issues, which a diagnosis of conjunctivitis might not fully explain.

According to a July 2021 article on PennVet’s website, “The researchers have not found evidence that the condition is a result of avian influenza, and have also ruled out West Nile virus and other flaviviruses, Newcastle disease virus, and other paramyxoviruses, herpesviruses, and poxviruses; and Trichomonas parasites. They don’t believe it’s related to a similar-looking conjunctivitis that has affected house finches this year”

An email has been sent to USGS requesting clarification on the diagnosis and whether this determination is final. This article will be updated should a response be received.


Update (1/18/2022) – USGS Public Affairs Specialist Marisa Lubeck emailed, “I checked with the USGS National Wildlife Health Center and they stated that yes, conjunctivitis was confirmed for many of the birds. However, they have not identified the causative agent. The mortality event appears to be over but the investigations by multiple research laboratories and university groups is continuing.”


Donna L. Cole is an award-winning investigative and multimedia reporter. She’s also a volunteer bird of prey rescuer.

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