Zoonotic Cryptosporidium and Giardia shedding by captured rangeland goats

Faecal shedding of Cryptosporidium and Giardia by captured rangeland goats was investigated using a longitudinal study with four faecal samples collected from 125 male goats once monthly for four months, commencing immediately after capture and transport to a commercial goat depot (feedlot). Goats were composite breed and aged approximately 9-12 months on arrival. Faecal samples were screened for Cryptosporidium and Giardia presence and concentration using quantitative PCR and sequencing at the 18S ribosomal RNA locus (Cryptosporidium), and glutamate dehydrogenase and β-giardin loci (Giardia). Longitudinal prevalence for Cryptosporidium was 27.2% (point prevalence range 3-14%) with 3 species identified: C. xiaoi (longitudinal prevalence 13.6%), C. ubiquitum (6.4%) and C. parvum (3.2%). Sub-typing at the gp60 locus identified C. ubiquitum XIIa, C. parvum IIaA17G2R1 and C. parvum IIaA17G4R1. This is the first report of the zoonotic C. parvum subtype IIaA17G4R1 in goats. The pattern of genotypes shed in faeces changed over the duration of study with C. ubiquitum identified only at the first and second samplings, and C. parvum identified only at the fourth sampling. Longitudinal prevalence for Giardia duodenalis was 29.6% (point prevalence range 4-12%) with all positives sub-typed as assemblage E. Only 2/125 goats were identified to be shedding Cryptosporidium or Giardia on more than one occasion. This is the first report of Cryptosporidium and Giardia genotypes in captured rangeland goats. Faecal shedding of zoonotic Cryptosporidium spp. and potentially zoonotic G. duodenalis has implications for food safety and effluent management. Keywords: Cryptosporidium; Giardia; Rangeland goats; zoonotic.