Imagemagick jpeg decode delegate missing with OS X Homebrew install

I recently converted from macports to homebrew and my previous macports Imagemagick install was working fine. I followed the homebrew instructions to chown /usr/local (somewhat apprehensively) and remove /usr/local/include and /usr/local/lib. When trying to work with any jpeg images, imagemagick chokes with:

no decode delegate for this image format

Here is a list of some relevant command output. As you can see, no jpeg/jpg delegate can be found.

convert -list configure => DELEGATES bzlib freetype png x11 xml zlib

identify -list configure => DELEGATES bzlib freetype png x11 xml zlib

However, jpeg lib was installed as part of the Imagemagick dependencies, so I'm not sure what's going on here.

brew list => imagemagick jasper jpeg libtiff little-cms nginx pcre

brew doctor => Your OS X is ripe for brewing. Any troubles you may be experiencing are likely purely psychosomatic.

identify --version => Version: ImageMagick 6.6.7-9 2011-04-06 Q16

Any ideas?