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An Investigation of Cryptosporidium parvum and Giardia lamblia and Environmental Stressors in Dairy Calves
Cryptosporidium parvum and Giardia lamblia are protozoal parasites that can cause gastroenteritis in dairy calves and are zoonotic diseases causing intestinal enteritis in humans. The objective of this study was to determine if environmental stressors promote oocyst shedding of C. parvum or G. lamblia in male dairy calves. The environmental stressors considered were arrival to the facility, transfer from isolation to the main barn, and processing (castration, dehorning, vaccination). Calves (n=18) were 3-5 d of age and were obtained from local producers. The calves remained in isolation for 21 d post arrival before transfer to the main barn and were kept in individual 1x2 m pens. Fecal samples were collected via rectum with an eSwab® or Para-Pak® vial. Fecal collections were taken within 24 h upon calf arrival, 24 h prior to the environmental stressor, and between 44 to 52 h after the environmental stressor. To determine the presence of C. parvum or G. lamblia, feces were analyzed using rapid immunochromatographic assay. Results indicated that no calves were positive for C. parvum or G. lamblia upon arrival to the facility. Three weeks later, testing detected 18% of the calves had C. parvum and 6% had G. lamblia prior to removal from isolation. When examined 44 to 52 h after removal from isolation 29% of the calves were positive for C. parvum and 24% for G. lamblia. Of samples collected 4 h before processing, C. parvum and G. lamblia were present in 6% and 47% of calves. When tested 44 to 52 h after processing no cases of C. parvum and 6 cases of G. lamblia were detected. The paired student t-test conducted before isolation removal (BIR) and after isolation removal (AIR) indicated no statistical significance for C. parvum (p= 0.2908) and G. lamblia (p= 0.1671). Samples collected before processing (BP) and after processing (AP) indicated no statistical significance for C. parvum (p= 0.1661) and G. lamblia (p= 0.2481). Based on the data G. lamblia was more prevalent than C. parvum. The data also indicates isolation may not be effective given the increased prevalence of infection from C. parvum and G. lamblia prior to removal from isolation. Processing also showed no increased prevalence of C. parvum or G. lamblia. Through monitoring the calves during isolation this procedure appears ineffective at reducing the prevalence of infection from C. parvum or G. lamblia.
Keywords: Cryptosporidium, Giardia, Immunochromatography