Erratum to: Parasitol Res (2008) 102:491–497 DOI 10.1007/s00436-007-0789-z

Due to a technical error, this article was unfortunately published twice.

The original (first) version of this article was published in Parasitol Res (2008) 102:211-217, and is available online at http://dx.doi.org/10.1007/s00436-007-0749-7.