Diagnosis of Veterinary Endoparasitic Infections: http://cal.vet.upenn.edu/projects/dxendopar/index.html
Parasites and Parasitic Diseases in Domestic Animals: http://cal.vet.upenn.edu/projects/merial/index.html
http://asp.unl.edu/--The American Society of Parasitologists web site
http://www.heartwormsociety.org--The American Heartworm Society web site
http://www.aavp.org--The American Association of Veterinary Parasitologists web site
http://www.ivis.org--Another source of information on veterinary parasites is "Companion and Exotic Animal Parasitology" edited by D. D. Bowman. This web based text can be found on the site maintained by The International Veterinary Information Service (IVIS).
http://www.accessdata.fda.gov/scripts/AnimalDrugsAtFDA/ -- The FDA "Green Book", a list of all animal drug products approved by the FDA for safety and effectiveness. This is a searchable site for antiparasite drugs labeled for use in the United States.