Giardiasis and Cryptosporidiosis in ruminants

Abstract

Although differing considerably with respect to their biology, the parasites Giardia duodenalis and Cryptosporidium parvum have often been discussed collectively because of their role as common causes of waterborne gastrointestinal disease in humans. Because both parasites are extremely common in ruminants, much of the discussion and research concerning G duodenalis and C parvum during the past decade has focused on their zoonotic potential and the role of ruminants as reservoirs for human infection. By contrast, the importance of these parasites as causes of disease and production losses in ruminants appears to have received little attention. Recent research indicates that, although both G duodenalis and C parvum infections in ruminants do pose some risk for zoonotic transmission, the risk is much less significant than was once believed and is easily managed. Research also indicates that, although G duodenalis is not likely to be a major cause of clinical disease in ruminants, it may have an important and overlooked impact on production. C parvum, by contrast, remains an important cause of diarrhea in neonatal ruminants, but it does not appear to be as significant a pathogen in beef calves as it is in dairy calves. In addition, abomasal cryptosporidiosis, caused by C andersoni, may be an emerging pathogen of significant economic importance in the beef and dairy cattle industries.