*Article* **Subtype Characterization and Zoonotic Potential of** *Cryptosporidium felis* **in Cats in Guangdong and Shanghai, China**

**Jiayu Li 1, Fuxian Yang 1, Ruobing Liang 1, Sheng Guo 1, Yaqiong Guo 1, Na Li 1, Yaoyu Feng 1,2,\* and Lihua Xiao 1,2,\***


**Abstract:** *Cryptosporidium felis* is an important cause of feline and human cryptosporidiosis. However, the transmission of this pathogen between humans and cats remains controversial, partially due to a lack of genetic characterization of isolates from cats. The present study was conducted to examine the genetic diversity of *C. felis* in cats in China and to assess their potential zoonotic transmission. A newly developed subtyping tool based on a sequence analysis of the 60-kDa glycoprotein (*gp60*) gene was employed to identify the subtypes of 30 cat-derived *C. felis* isolates from Guangdong and Shanghai. Altogether, 20 *C. felis* isolates were successfully subtyped. The results of the sequence alignment showed a high genetic diversity, with 13 novel subtypes and 2 known subtypes of the XIXa subtype family being identified. The known subtypes were previously detected in humans, while some of the subtypes formed well-supported subclusters with human-derived subtypes from other countries in a phylogenetic analysis of the *gp60* sequences. The results of this study confirmed the high genetic diversity of the XIXa subtype family of *C. felis*. The common occurrence of this subtype family in both humans and cats suggests that there could be cross-species transmission of *C. felis*.

**Keywords:** *Cryptosporidium felis*; 60-kDa glycoprotein; subtypes; zoonotic transmission
