Rapid detection and quantification of Cryptosporidium baileyi oocysts in feces and organs of chickens using a microscopic slide flotation method

A simple semiquantitative microscopic slide flotation (MSF) method using mo dified Sheather's sugar solution (MSSS) is presented for the rapid detectio n and quantification of Cryptosporidium baileyi oocysts in the feces and mu cosal and/or organ scrapings of chickens. Oocyst shedding was evaluated by examination of the surface of coverslips, and the average quantitative scor e (0-5) recorded for 10 microscopic fields (magnification x250) is reported . The equivalence between these scores and the actual number of oocysts cou nted per gram of feces was assessed (r(s) = 0.89; P < 0.001). The applicabi lity of this method was tested by comparison of the kinetics of oocyst shed ding in feces of inoculated chickens with those reported by other authors w orking under similar conditions, In organs the MSF method was compared to h istology. Fewer false-negative results were obtained using MSF versus the h istology method. The MSF method was particularly more efficient in tracheae with low levels of infection and in the lungs, regardless of the level of infection. The MSF method was also very efficient in detecting oocysts in a ir sacs from chickens with aerosacculitis. It provides a specific and suffi ciently sensitive, simple, rapid, reliable, and low-cost means of diagnosin g C. baileyi in the feces and organs of chickens. This method can be used i n the routine diagnosis of cryptosporidia in chickens, and it could be exte nded to other avian species and used in epidemiology studies to evaluate th e prevalence of cryptosporidiosis in fowl.