The Prevalence of Cryptosporidium spp. and Giardia duodenalis in Marmota himalayana (Rodentia: Sciuridae) in the Qinghai Tibetan Plateau area, China.

Background: Cryptosporidium and Giardia are well-known important intestinal zoonotic pathogens that can infect various hosts and cause diarrhoeal diseases. We aimed to determine the epidemiological prevalence and molecular characterization of Cryptosporidium and Giardia species in Himalayan marmot (Marmota himalayana, class Marmota) in the Qinghai Tibetan Plateau Area of Qinghai Province, Northwest China.

Methods: Overall, 243 Himalayan marmot fecal samples were collected in 2017 and in 2019 and a two-step nested PCR technique was performed to amplify the fragments of the SSU rRNA gene of Cryptosporidium and 18S ribosomal RNA gene of Giardia. Molecular characterization of Cryptosporidium was performed with the primary primers NDIAGF2 and N-DIAGR2, the secondary primers CPB-DIAGF and CPB-DIAGR. Similarly, molecular characterization of Giardia was used the first primers Gia2029 and Gia2150c, the secondary primers RH11 and RH4. The positive PCR products were sequenced and the sequences were processed by Clustal Omega and BLAST. Phylogenetic analysis was achieved by NJ method in MEGA.

Results: The infection rate of Cryptosporidium spp. and G. duodenalis was 4.9% (12/243) and 0.8% (2/243) in M. himalayana, respectively. Cryptosporidium spp. are characterized as novel genotypes Cryptosporidium marmot genotype I (n=3) and Cryptosporidium marmot genotype II (n=9); G. duodenalis assemblage A (n=2) was found in M. himalayana.

Conclusion: This is the first report of Cryptosporidium spp. and G. duodenalis infections in M. himalayana in Qinghai of Northwest China. The results indicate the existence of Cryptosporidium species and G. duodenalis infections that may have a potential public health significance.