A survey of prevalence among birds in two zoos in China.

Background: Cryptosporidiosis is an important zoonotic protozoan disease worldwide, but few studies on this disease have been performed in wild birds; thus, our knowledge of this disease is insufficient, even in zoo birds. Animals in zoos are possible zoonotic disease reservoirs, potentially resulting in zoonotic agent spillover to humans; accordingly, our understanding of such phenomena should be improved.

Methods: A total of 263 fresh fecal samples from 43 avian species were randomly collected from the Beijing Zoo and Harbin North Forest Zoo and screened for the prevalence of by 18S rRNA gene sequencing. species were distinguished based on the combined results of phylogenetic tree and genetic distance analyses conducted with the inclusion of seven avian species and 13 avian genotypes. The genetic diversity of among different hosts, including humans, cattle, dogs, and birds, and the genetic diversity of avian among avian hosts in China, Iraq and Brazil were determined based on 18S rRNA haplotypes.

Results: The results of PCR targeting the 18S rRNA gene revealed that 1.9% (5/263) of the samples were -positive. Four of the five -positive samples originated from white cranes (), and one originated from a flamingo (). Avian isolates, including the isolates examined in the present study, showed gene flow with other isolates from different types of hosts, including humans, cattle and dogs, indicating that zoo birds potentially pose zoonotic and pathogenic risks to humans and animals. Additionally, gene flow between avian isolates from China and Brazil was detected.

Conclusions: To the best of our knowledge, our results demonstrate infection in a flamingo () and white cranes () for the first time. The results of our study provide an important reference for understanding the host range, biological characteristics, and molecular epidemiology of .