Cryptosporidium of birds in pet markets in Wuhan city, Hubei, China

Abstract

Cryptosporidium is a group of protistan parasites of a range of vertebrates including mammals and birds. Stimulated by previous work that revealed "zoonotic" Cryptosporidium meleagridis subtypes (i.e. IIIbA26G1R1b and IIIbA22G1R1c) in diarrhoeic children and domestic chickens in Wuhan city and environs in Hubei Province, China, here we explored whether zoonotic C. meleagridis subtypes might also occur in pet birds in Wuhan city. From 11 bird markets in this city, we collected 322 faecal samples from 48 species of birds (representing six taxonomic orders), isolated genomic DNA and then conducted PCR-based sequencing of genetic markers in the small subunit (SSU) of the nuclear ribosomal RNA and the 60 kDa glycoprotein (gp60) genes of Cryptosporidium. Using SSU, Cryptosporidium was detected in 55 (17%) of the 322 samples. Cryptosporidium avium, C. baileyi, C. meleagridis, C. muris and C. proventriculi were characterised in 18%, 47%, 11%, 2% and 20% of the 55 samples, respectively, and a novel Cryptosporidium galli-like taxon in one sample. Using gp60, only one subtype (IIIeA17G2R1) of C. meleagridis was identified, which had not been detected in a previous study of diarrhoeic children in Wuhan. However, IIIe subtypes have been found in both humans and birds around the world. The relatively high prevalence and genetic diversity of Cryptosporidium recorded here in pet birds raise awareness about possible reservoirs of zoonotic variants of Cryptosporidium in birds in Wuhan, and potentially, other provinces in China.

Keywords: Cryptosporidium; PCR-based sequencing; Pet bird; Zoonotic potential.

Graphical abstract

Fig. 1

Phylogenetic relationships of Cryptosporidium taxa constructed using the neighbour-joining distance method, employing nucleotide sequence data from a portion of the small subunit of the nuclear ribosomal RNA gene (SSU). Cryptosporidium species or genotypes characterised in the present study are in bold-type. The GenBank accession number precedes the species designation; the number of samples of a particular species/genotype is indicated in parentheses. The scale-bar represents the number of substitutions per site. Cryptosporidium molnari (GenBank: HM243547) was used as an outgroup. Bootstrap support is indicated at the nodes

Fig. 2

Phylogenetic relationships of Cryptosporidium meleagridis constructed using the neighbour-joining distance method, employing nucleotide sequence data from fragment of the 60 kDa glycoprotein (gp60) gene. Cryptosporidium meleagridis sequence generated in the present study is in bold-type. The GenBank accession number precedes the species designation; the number of samples of a particular species/genotype is indicated in parentheses. The scale-bar represents the number of substitutions per site. Cryptosporidium meleagridis subtype IIIb (GenBank: KJ210609) was used as the outgroup. Bootstrap support is indicated at the nodes