*2.4. Phylogenetic Analysis of C. felis Subtypes*

The *gp60* sequences from the 20 *C. felis* isolates were all placed in the XIXa subtype family in the phylogenetic tree (Figure 2). They formed several subclusters with strong bootstrap support with *C. felis* subtypes from humans. Among the novel subtypes identified in the study, 4 subtypes (XIXa-90, XIXa-91, XIXa-92, and XIXa-93) formed a subcluster with several subtypes identified from humans and cats in several European countries and another subtype (XIXa-82) formed a subcluster with several subtypes from humans and cats in the United Kingdom and Sweden. In addition, two cat-derived subtypes (XIXa-87 and XIXa-88) in 4 isolates from this study formed their own subcluster. As expected, the known subtypes (XIXa-39 and XIXa-40) identified in the present study and previously in humans from the United Kingdom and Indonesia formed a subcluster (Figure 2).

**Figure 2.** Phylogenetic relationship among XIXa subtypes of *Cryptosporidium felis* identified in this study and references from GenBank based on maximum likelihood analysis of the sequences of partial *gp60* gene: bootstrap values over 50 percent are shown on the branches of the phylogenetic tree. The human-, monkey-, and cat-derived isolates are indicated by rhombus, star, and round labels, respectively. Sequences from different countries are shown in different colors. The names of known subtype families of *C. felis* are shown on the right side of the phylogenetic tree. The subtype name of each isolate is labeled at the end of the sequence.
