Research

Prevalence of the protozoan parasite Cryptosporidium on three organic pig farms in Denmark

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Abstract

Pigs are a potential source of contamination with Cryptosporidium spp., which can lead to infection in humans. Two species C. parvum and C. hominis can cause an acute diarrheal illness in humans, which can become severe in e.g. patients with HIV. The oocyst can survive for long periods in the environment and is resistant to many common disinfectants. In order to estimate the prevalence of the zoonotic parasite Cryptosporidium in organic pigs and to improve our knowledge of the parasite epidemiology, the prevalence was monitored four times between September 2011 and June 2012 in three Danish organic pig farms. Faecal samples were collected for examination of Cryptosporidium spp. with a total of 994 pigs grouped as sows, fatteners, young pigs and piglets. The number of pigs in each age group was 298, 232, 315 and 161 respectively, distributed on the three farms. Faecal samples were collected four times and oocysts were counted by microscopy. The overall prevalence of Cryptosporidium spp. was 38%. The prevalence in the four age groups was very different, with 3% of the sows, 40% of the fatteners, 65% of the young pigs and 45% of the piglets found positive. There was no noteworthy difference in the overall prevalence between farms (33%-42%) or between the four sampling times (33%-42%). The intensity of the Cryptosporidium infection was dependent on the age of the pigs, with the younger having the highest OPG. Only in the young pigs and the piglets more than 105 OPG was seen and the 10 pigs with the highest OPG were all piglets. There were no noteworthy differences in the intensity of the Cryptosporidium infection between the four sampling times, but there was an apparent association between the number of positive sows and the number of piglets with high OPG, since 9/10 pigs with the highest OPG were found on the same farm which also had the highest prevalence in sows. Further studies on the species and zoonotic potential of the Cryptosporidium oocysts are ongoing.