An Epidemiological Assessment of Cryptosporidium and Giardia spp. Infection in Pet Animals from Taiwan

SIMPLE SUMMARY: Cryptosporidium spp. and Giardia duodenalis, enteric protozoan pathogens affecting humans and animals, elicit substantial global public concern. This study conducted in Taiwan sought to determine the prevalence and co-infection rates of Cryptosporidium spp. and G. duodenalis in dogs and cats. The investigation encompassed an analysis of infection rates and associated risk factors within the surveyed population. Predominantly identified species were C. canis and C. felis, aligning with canine-specific assemblages C and D. In contrast, the infrequent presence of human-specific assemblage A was noted in Giardia-positive samples. Phylogenetic analysis alluded to the potential for zoonotic transmission originating from domesticated animals. This underscores the role of pets as possible reservoirs for the transmission of cryptosporidiosis and giardiasis to humans in Taiwan. ABSTRACT: Cryptosporidium spp. and Giardia duodenalis are enteric protozoan pathogens in humans. and animals. Companion animals infected with zoonotic species/assemblages are a matter of major public concern around the world. The objectives of the present study were to determine the prevalences of Cryptosporidium spp. and G. duodenalis infections and their co-infection statuses in dogs and cats living in Taiwan and to identify the species and assemblages. Fecal samples were collected from local animal shelters (n = 285) and a veterinary hospital (n = 108). Nested polymerase chain reaction (PCR) was performed using the SSU-rRNA, β-giardin, and glutamate dehydrogenase genes for Cryptosporidium spp. and G. duodenalis, respectively. Results showed that the overall prevalences of Cryptosporidium and G. duodenalis were 7.38% (29/393) and 10.69% (42/393). In addition, co-infection was detected in 1.02% (4/393) of all samples. Sample source, clinical sign, and breed may be risk factors that influence the infection rate. In Cryptosporidium-positive samples, C. canis and C. felis were detected most frequently. Although the canine-specific assemblages C and D (37/42) were dominant, the zoonotic human-specific assemblage A (1/42) was also found in Giardia-positive samples. Phylogenetic analysis revealed that most positive samples belonged to host-specific subtypes/assemblages, while some Cryptosporidium or Giardia-positive samples could be zoonotic. The findings suggested that pet animals could be a cause of zoonotic transmission, causing human cryptosporidiosis and giardiasis in Taiwan.