Prevalence and pathogen load of Cryptosporidium and Giardia in sheep faeces collected from saleyards and in abattoir effluent in Western Australia

The prevalence of Cryptosporidium and Giardia in faeces collected from sheep at sale yards in Western Australia and for abattoir effluent was determined using a quantitative multiplex PCR (qPCR). A total of 474 faecal samples were collected from sheep at two saleyards on four occasions (April-July 2014) and 96 effluent samples were collected from an abattoir over a four month period (April-July). The overall prevalence of Cryptosporidium in sheep faeces was 6.5% (31/474), with the zoonotic species Cryptosporidium parvum and Cryptosporidium ubiquitum accounting for 54.2% of the typed positive samples. Subtyping of the C. parvum and C. ubiquitum positives at the gp60 locus identified four C. parvum positives as IIdA18G1 and nine C. ubiquitum isolates as the XIId subtype. The overall prevalence of Giardia in sheep faeces was 6.3% (30/474), with the non-zoonotic assemblage E responsible for the majority (81.5%) of positive isolates typed. Median Cryptosporidium and Giardia oo/cyst concentrations in positive faecal samples were 1.7×103 oocysts g-1 (range 32-3.7×106 oocysts g-1) and 2.5×103 cysts g-1 (range 143-7.5×105 cysts g-1) respectively. Cryptosporidium and Giardia were identified in 10.4% (10/96) and 5.2% (5/96) of abattoir effluent samples (respectively). Median Cryptosporidium and Giardia oo/cyst concentrations in positive effluent samples was 1.3×103 cysts g-1 (range 393-1.5×104) and 1.5×104 oocysts g-1 (range 759-4.8×103) respectively. These findings have important implications for the sheep meat industry because Cryptosporidium and Giardia have both been associated with reduced carcase productivity in sheep, and the contamination of lamb carcases and watersheds with zoonotic species have important public health consequences.