Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2015 Apr 22:8:240.
doi: 10.1186/s13071-015-0855-9.

Cross sectional study of prevalence, genetic diversity and zoonotic potential of Cryptosporidium parvum cycling in New Zealand dairy farms

Julanda Al Mawly  1 , Alex Grinberg  2 , Niluka Velathanthiri  3 , Nigel French  4
Affiliations

Cross sectional study of prevalence, genetic diversity and zoonotic potential of Cryptosporidium parvum cycling in New Zealand dairy farms

Julanda Al Mawly et al. Parasit Vectors. .

Abstract

Background: The estimation of the prevalence and zoonotic potential of Cryptosporidium parvum cycling in bovine populations requires the use of genotyping, as several morphologically similar non-parvum genetic variants of unproven clinical and public health impact are found in cattle. However, robust C. parvum prevalence estimates in cattle are lacking and comparative data of bovine and human isolates collected from the same regions are scarce. Thus, the relative contribution of the C. parvum oocysts released by farmed animals to animal and human cryptosporidiosis burden is, in general, poorly understood.

Methods: The New Zealand farm-level C. parvum prevalence was estimated using a cross-sectional sample of 1283 faecal specimens collected from newborn calves on 97 dairy farms. Faeces were analysed by immunofluorescence and the Cryptosporidium parasites were genetically identified. Finally, bovine C. parvum were genetically compared with historical human clinical isolates using a bilocus subtyping scheme.

Results: Immunofluoresence-positive faeces were found in 63/97 (65%) farms. C. parvum was identified in 49 (50.5%) farms, C. bovis in 6 (6.1%) farms, and on 8 (8.2%) farms the species could not be identified. The dominant C. parvum genetic variants were geographically widespread and found in both host populations, but several variants were found in humans only.

Conclusions: Phenotypic tests offered by New Zealand veterinary diagnostic laboratories for the diagnosis of C. parvum may have moderate to high positive predictive values for this species. The genetic similarities observed between the human and bovine parasites support a model considering calves as significant amplifiers of zoonotic C. parvum in New Zealand. However, data suggest that transmission routes not associated with dairy cattle should also be taken into account in future source-attribution studies of human cryptosporidiosis.

PubMed Disclaimer

References

    1. Fayer R. Taxonomy and species delimitation in Cryptosporidium. Exp Parasitol. 2010;124:90–7. doi: 10.1016/j.exppara.2009.03.005. - DOI - PubMed
    1. Al Mawly J, Grinberg A, Prattley D, Moffat J, Marshall J, French NP. Risk factors for neonatal calf diarrhoea and enteropathogen shedding in New Zealand dairy farms. Vet J. 2015;203:155–60. doi: 10.1016/j.tvjl.2015.01.010. - DOI - PMC - PubMed
    1. de Graaf DC, Vanopdenbosch E, Ortega-Mora LM, Abbassi H, Peeters JE. A review of the importance of cryptosporidiosis in farm animals. Int J Parasitol. 1999;29:1269–87. doi: 10.1016/S0020-7519(99)00076-4. - DOI - PMC - PubMed
    1. Hunter PR, Thompson RCA. The zoonotic transmission of Giardia and Cryptosporidium. Int J Parasitol. 2005;35:1181–90. doi: 10.1016/j.ijpara.2005.07.009. - DOI - PubMed
    1. Learmonth J, Ionas G, Pita A, Cowie R. Identification and genetic characterisation of Giardia and Cryptosporidium strains in humans and dairy cattle in the Waikato region of New Zealand. Water Sci Technol. 2003;47:21–6. - PubMed

Publication types