Bird eye disease could give insight to how human diseases are transmitted

CheepShot/via Flickr
August 18, 2014

The Ebola outbreak has gotten so serious it’s being called an epidemic. A recent study from Cornell University on an eye disease in certain birds could help us understand how Ebola and other human diseases are transmitted. Morning Edition Host Monica Sandreczki recently talked with Andre Dondt with the Lab of Ornithology at Cornell University and worked on the study.

Morning Edition : Reading in your recent study, you had thought it was specific to house finches, but you’re finding it in other species as well?

Andre Dondt: When we started the study, we knew it occurred in house finches and found it occasionally in other finches – the American goldfinch, the purple finch – but rarely, only rarely. And, we didn’t really find it in many other bird species at all, but we looked a bit.. Then in the second round of the grant we decided to go beyond this and test all the birds around Ithaca here in New York state that we could trap and sample them to see if we could find evidence of infection. In the paper you’re referring to that we just got published shows that most bird species that we trapped, sufficient numbers of, we found evidence either of antibodies in the blood or bacterial DNA in the eye swabs.

What’s interesting is that in the other species, it doesn’t cause visible disease, so the birds are infected because we detect antibodies, but the birds don’t look sick when we trap them, so they seem to be able to handle this infection with no problems. Like many of us is infected with bacterial advice all the time, but to most of them we are resistant and we don’t contract the disease.

ME: What does it look like? I guess I’m imagining a bird with pink eye.

AD:  When they get eye infection, the eyes look gross, really terrible. If you imagine an infection on your finger with puss coming out. The conjunctive eyeset in which the eye is embedded in, swells, and sometimes swells so much the bird gets blind in that eye.

ME : So it’s not typically deadly?

AD : No, but if they’re sick then they’re more likely to get taken by a predator or not be able to find food and die of starvation.

ME : Wow, that it’s not even concentrated in one area or one species more than another?

AD : One of the interesting things that was found a few years ago in Malaysia actually by a Scottish scientist who had found mycoplasma in Scottish crows. He collaborated with colleagues in Malaysia and they sampled Malaysian crows and they also found it. So my impression is, if you look for it, you’ll find it, but most people don’t look for it because, at this point, it’s not really important. It doesn’t cause disease, doesn’t cause mortality. But it might be a reservoir that could transmit to other species that this is where, if you have an interest in wildlife diseases, it’s important to know what the reservoirs are.

ME : What do you mean, “reservoirs”?

AD : Reservoir is a host that carries the organism without causing disease and can transmit it to another organism which is susceptible. There again Ebola, is carried by fruit bats, we know that. In fruit bats, it doesn’t cause disease, but when people get infected one way or another from this fruit bat, people get very sick and humans die. So in fruit bats, it doesn’t cause disease. So the fruit bat is the reservoir and the human is the unfortunate host that can’t support the disease.

ME : Then it’s a matter of trying to understand how this spreads to other animals and how it’s carried?

AD : Right, when you think about, the general relevance is that for whatever reason, mycoplasma jumped from poultry to, well we know it jumped from poultry to house finches more than once, but it did so only once successfully. So, what is it that allowed this host jump to be successful? And once it happened, what happens in the new host? So that’s to some extent why, what we’re doing is relevant for understanding human diseases also.