The author would like to make the following correction to the article. On page 2, line 8 the sentence:
On the other hand, there were no significant differences between values of mean intensity (13.9 in urban compared with 12.1 in rural sites) nor in mean abundance of infection (1.5 in urban compared with 0.1 in rural sites).
Should instead read:
On the other hand, there were no significant differences between values of mean intensity (13.9 in urban compared with 1.5 in rural sites) nor in mean abundance of infection (12.1 in urban compared with 0.1 in rural sites).