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Wild birds of declining European species are dying from a thiamine deficiency syndrome

  1. Henrik Sundberga
  1. aDepartment of Applied Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden;
  2. bInstitute of Biology, University of Iceland, IS-101 Reykjavík, Iceland;
  3. cReykjanes Environmental Research Institute, IS-245 Sandgerði, Iceland; and
  4. dDepartment of Wildlife, Fish, and Environment, National Veterinary Institute, SE-751 89 Uppsala, Sweden

  1. Edited by John E. Halver, University of Washington, Seattle, WA, and approved May 29, 2009 (received for review March 22, 2009)

Abstract

Wild birds of several species are dying in large numbers from an idiopathic paralytic disease in the Baltic Sea area. Here, we demonstrate strong relationships between this disease, breeding failure, and thiamine (vitamin B1) deficiency in eggs, pulli, and full-grown individuals. Thiamine is essential for vertebrates, and its diphosphorylated form functions as a cofactor for several life sustaining enzymes, whereas the triphosphorylated form is necessary for the functioning of neuronal membranes. Paralyzed individuals were remedied by thiamine treatment. Moreover, thiamine deficiency and detrimental effects on thiamine-dependent enzymes were demonstrated in the yolk, liver, and brain. We propose that the mortality and breeding failure are part of a thiamine deficiency syndrome, which may have contributed significantly to declines in many bird populations during the last decades.

Footnotes

  • 1To whom correspondence should be addressed. E-mail: lennart.balk{at}itm.su.se

  • Author contributions: L.B. and P.-Å.H. designed research; L.B., P.-Å.H., G.Å., M.H., U.T., T.H., G.T.H., Y.Z., D.B., and T.M. performed research; L.B., G.Å., and T.H. analyzed data; and L.B., T.H., and H.S. wrote the paper.

  • The authors declare no conflict of interest.

  • This article is a PNAS Direct Submission.

  • This article contains supporting information online at www.pnas.org/cgi/content/full/0902903106/DCSupplemental.

  • Received March 22, 2009.

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