CDC pages - these are excellent!

Main page at CDC for parasites: http://www.dpd.cdc.gov/DPDx/HTML/Para_Health.htm

Relevant pages for MMID:

Ascaris Diphylobothrium latum (fish tapeworm) Strongyloides Chagas disease Leishmania
Entamoeba histolytica Taenia (tapeworms) Schistosomes Malaria Trichinella
Hookworms Enterobius (pinworm) Trichuris (whipworm) Cysticercosis Visceral larva migrans
Cryptosporidium Giardia Babesia Echinococcosis