“Avian diphtheria” in penguins: more questions than answers, I’m afraid.

30 11 2010

First off, you may notice a new field in our database next time you report a dead bird. “cable tie number, if applicable” now appears in the section on how you marked your carcass. We have sent individually numbered cable ties to a subset of volunteers to begin tracking individual carcasses. The numbered ties will allow us to determine how long a specific bird remains on the beach, or whether birds wash out to sea after being tagged and subsequently wash up on a different SEANET beach.

If you have received the numbered ties, please report the number you placed on the bird in this new field. Eventually, we hope to get numbered ties to all our volunteers, and we are excited to see what the data from this new method will show.

 

Lesions in the mouth of an affected penguin chick. But what is the infection?

Now, some seabird disease news: Yellow-eyed penguins on New Zealand’s Otago Peninsula are suffering from an outbreak of avian diphtheria. “Avian diphtheria” is a term loosely applied to a couple of very different infections. It can be applied to an avian pox virus, which leads to wart like growths either on unfeathered skin (like the feet or around the eyes) or inside the mouth and throat. Avian pox is highly contagious, and can be transmitted by mosquitoes, or by direct contact between birds. The virus survives for a remarkably long time in the environment, and virus-containing scabs that drop to the soil can remain infectious for months or even years. “Avian diphtheria” is also sometimes used to refer to infections with bacteria called Corynebacterium diphtheriae. This bacterium is the one that also causes human diphtheria, and leads to a leathery membrane forming in the throat. The bacteria also produce a toxin that can lead to organ failure. In this penguin report, it is unclear which of these infections is suspected. No laboratory results are yet available.

Some of the chicks have been taken in to medical facilities. News reports state that the birds are being given antibiotics and fluids. If the infection is a pox virus, then the antibiotics are presumably to stave off any secondary bacterial infection, since the drugs have no effect on the virus itself. If Corynebacteria are involved, then the antibiotics will be used to treat the infection directly and reduce the effects of the bacterial toxin.

Perhaps the greatest risk to the birds is starvation and dehydration, since lesions in the mouth and throat can make swallowing excruciatingly painful. With supportive care, officials expect most of the chicks to survive.

If more information on the nature of this infection and its potential effect on the penguin population become available, you can be sure that your SEANET blogger will share it with you, since she is a serious bird disease geek, and really wants to know what these birds actually have.

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One response

3 01 2011
Aimee

Hi-ya all,
Love this blog – it’s great. Some of it “heavy” and some of it “light” (yellow rubber ducky), which takes the distressful edge off the heavier stuff. All of it of interest to me and much of it for the scientific minded, climate change intrigued, naturalist-lover of birds and other creatures of the earth (besides us humans) in general. I also want to acknowledge your hard work in getting up the “professional” SEANET website, which looks as you had hoped – polished, clear, clean and oh so professional. Thank you for your dedication one and all. Aimee – Hope in Maine

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