PREVALENCE OF THE PROTOZOAN PARASITE CRYPTOSPORIDIUM IN THREE ORGANIC PIG FARMS IN DENMARK

Summary in the original language of the document

Pigs are potential sources of contamination with Cryptosporidium spp., which can lead to infection in humans. Cryptosporidiosis in humans is primarily caused by two species, C. hominis and the zoonotic C. parvum, however, other species including C. suis and C. scrofarum are able to cause zoonotic infection. The oocysts can survive for long periods in the environment and are able to resist most disinfectants. In order to estimate the prevalence of Cryptosporidium spp. in organic pigs and to improve knowledge of the epidemiology, the oocyst excretion was monitored at quarterly intervals during the period September 2011 to June 2012 in each of three organic, Danish pig farms. Faecal samples for examination of Cryptosporidium spp. were collected from 994 pigs allocated into four age groups, piglets (n = 161), weaners (n = 315), fatteners (n = 232) and sows (n = 286), distributed on the three farms and four sampling times. Oocysts were quantified by immunofluorescence microscopy, and the overall prevalence of Cryptosporidium spp. was found to be 38%. The prevalence varied significantly between age groups with 45% piglets, 65% weaners, 40% fatteners and 3% sows found positive. No significant difference in the overall prevalence was detected between farms or seasons. Intensity of infection was age dependent with piglets and weaners having the highest oocyst excretion. No clear differences in the intensity of infections were seen between the four sampling times, but an apparent correlation was observed between number of positive sows and number of piglets with massive oocyst excretion (>105 oocysts per gram faeces ( OPG). Nine of the ten animals with highest OPG originated from the same farm which also had the highest prevalence in sows. Molecular characterisation of the collected Cryptosporidium isolates is ongoing and will reveal the zoonotic potential as well as the genetic variation between farms, seasons and age groups.