With this wiki2html.sh bash script and pandoc program, you can convert markdown to html.
Usage: In the vim list section of the .vimrcfile, include options:
let g:vimwiki_list = [{'path': ‘your_wiki_place',
  \ 'path_html': ‘wiki_html_location’,
  \ 'syntax': 'markdown',
 \ 'ext': '.md',