Dominance of the zoonotic pathogen Cryptosporidium meleagridis in broiler chickens in Guangdong, China, reveals evidence of cross-transmission.

BACKGROUND

Cryptosporidium is one of the most prevalent parasites infecting both birds and mammals. To examine the prevalence of Cryptosporidium species and evaluate the public health significance of domestic chickens in Guangdong Province, southern China, we analyzed 1001 fecal samples from 43 intensive broiler chicken farms across six distinct geographical regions.

METHODS

Individual DNA samples were subjected to nested PCR-based amplification and sequencing of the small subunit of the nuclear ribosomal RNA gene (SSU rRNA). Analysis of the 60 kDa glycoprotein gene (gp60) was performed to characterize the subtypes of C. meleagridis.

RESULTS

The overall prevalence of Cryptosporidium was 13.2% (95% CI 11.1-15.3) (24 of 43 farms), with C. meleagridis (7.8%), C. baileyi (4.8%) and mixed infections (0.6%). Using the gp60 gene, three subtype families, IIIb, IIIe and IIIg, were identified, including six subtypes: one novel (IIIgA25G3R1a) and five previously reported (IIIbA23G1R1c, IIIbA24G1R1, IIIbA21G1R1a, IIIeA17G2R1 and IIIeA26G2R1). Within these subtypes, five known subtypes were genetically identical to those identified in humans.

CONCLUSIONS

This is the first report of C. meleagridis in chickens from Guangdong. The frequent occurrence of C. meleagridis in domestic chickens and the common C. meleagridis subtypes identified in both humans and chickens is of public health significance. Our study indicates that broiler chickens represent a potential zoonotic risk for the transmission of Cryptosporidium in this region.