High genetic diversity of Giardia duodenalis assemblage E in Chinese dairy cattle.

Giardia duodenalis is a common protozoan parasite that can infect humans and animals. Although previous studies demonstrated that the assemblage E of G. duodenalis is prevalent in cattle, studies on its genetic diversity were mostly based on single loci and very few involved multilocus analysis. To better understand the genetic variability and structure of G. duodenalis assemblage E in Chinese dairy cattle, 651 multilocus sequences derived from nine provinces (Gansu, Guangdong, Henan, Jiangsu, Ningxia, Shaanxi, Shanghai, Sichuan and Xinjiang) of China were analyzed in this study. Results showed that a total of 220 haplotypes were identified in the G. duodenalis assemblage E, with a high haplotype diversity (Hd = 0.97225) and low nucleotide diversity (π = 0.00259). The genetic differentiation index (FST) and gene flow (Nm) results indicated low degree of genetic differentiation, implying frequent genetic communication. Combined with the analysis of molecular variance (AMOVA), genetic variation within populations (81.7%) was higher than that among populations (18.3%), indicating low degree of genetic differentiation between populations. Such low rates of gene differentiation supported no significant correlations with geographical divisions. Moreover, both negative Tajima's D and Fu's FS values of neutrality tests and unimodal curve of mismatch distribution analyses indicated that G. duodenalis assemblage E population in Chinese dairy cattle had experienced demographic expansion. Overall, these findings contribute to an improved understanding of the population genetics and evolutionary biology of G. duodenalis assemblage E and assist in its control in cattle.

Occurrence and multilocus genotyping of Giardia duodenalis in captive non-human primates from 12 zoos in China.

Giardia duodenalis is a common enteric protozoan that infects a range of hosts including humans and other mammals. Multilocus genotyping of G. duodenalis in captive non-human primates (NHPs) from zoos in China is limited. In this study, we evaluated 302 NHP fecal samples collected from 32 different NHP species. The primates were from 12 zoos distributed across eight provinces and two municipalities (Chongqing and Beijing) of China. The overall infection rate was 8.3% (25/302). The six G. duodenalis-positive zoos and their infection rates were: Suzhou Zoo (40.0%, 4/10), Yangzhou Zoo (22.2%, 2/9), Dalian Zoo (16.7%, 4/24), Chengdu Zoo (12.8%, 6/47), Guiyang Forest Wildlife Zoo (12.1%, 7/58), and Changsha Zoo (4.7%, 2/43). Molecular analysis of three loci, beta-giardin (bg), triose phosphate isomerase (tpi), and glutamate dehydrogenase (gdh), showed high genetic heterogeneity, and seven novel subtypes (BIII-1, MB10-1, WB8-1, B14-1, MB9-1, DN7-1, and BIV-1) were detected within assemblage B. Additional analysis revealed 12 different assemblage B multilocus genotypes (MLGs), one known MLG and 11 novel MLGs. Based on phylogenetic analysis, 12 assemblage B MLGs formed two main clades, MLG-SW (10-12, 18) and MLG-SW (13, 14, 16, 17), the other four MLG-SW (15, 19, 20, 21) were scattered throughout the phylogenetic tree in this study. Using multilocus genotyping, this study expands our understanding of the occurrence of Giardia infection and genetic variation in Giardia in captive non-human primates from zoos in China.

Occurrence and multilocus genotyping of Giardia duodenalis from post-weaned dairy calves in Sichuan province, China.

Giardia duodenalis is a zoonotic parasitic protist and poses a threat to human and animal health. This study investigated the occurrence of G. duodenalis infection in post-weaned calves from Sichuan province, China. Faecal samples were collected from a total of 306 post-weaned calves (3-12 months old) from 10 farms, including 4 intensive feeding farms and 6 free-ranging farms. The overall infection rate of G. duodenalis was 41.2% (126/306) based on the PCR results at any of the three genetic loci: beta-giardin (bg), triose-phosphate isomerase (tpi) and glutamate dehydrogenase (gdh) genes. Giardia duodenalis assemblages E (n = 115, 91.3%), A (n = 3, 2.4%), and A mixed with E (n = 8, 6.3%) were identified among the 126 positive specimens. Multilocus sequence typing of G. duodenalis revealed 34 assemblage E multilocus genotypes (MLGs), 1 assemblage A MLG and 7 mixed assemblage (A and E) MLGs. The eBURST data showed a high degree of genetic diversity within assemblage E MLGs. The phylogenetic tree revealed that MLG E3 was the primary MLG subtype in Sichuan province and also the most widely distributed in China.

Occurrence and genotyping of Giardia duodenalis and Cryptosporidium in pre-weaned dairy calves in central Sichuan province, China.

Giardia duodenalis and Cryptosporidium spp. are common human and animal pathogens. They have increasingly been reported in dairy calves in recent years; however, multilocus genotyping information for G. duodenalis and Cryptosporidium infecting pre-weaned dairy calves in southwestern China is limited. In the present study, the prevalence of G. duodenalis and Cryptosporidium spp. in pre-weaned dairy calves in central Sichuan province was determined and the pathogens were analyzed molecularly. Of 278 fecal samples from pre-weaned dairy calves, 26 (9.4%) were positive for G. duodenalis and 40 (14.4%) were positive for Cryptosporidium spp. Cryptosporidium bovis (n = 28), Cryptosporidium ryanae (n = 5) and Cryptosporidium parvum (n = 7) were detected. All seven C. parvum isolates were successfully subtyped based on the gp60 gene sequence, and only IIdA15G1 was detected. Multilocus sequence typing of G. duodenalis based on beta-giardin (bg), triose phosphate isomerase (tpi) and glutamate dehydrogenase (gdh) genes revealed 19 different assemblage E multilocus genotypes (two known and 17 unpublished genotypes). Based on eBURST analysis, a high degree of genetic diversity within assemblage E was observed in pre-weaned dairy calves in Sichuan province. To the best of our knowledge, this is the first study using multilocus sequence typing and eBURST analysis to characterize G. duodenalis in pre-weaned dairy calves in southwestern China.

Occurrence and genetic characterization of Giardia duodenalis and Cryptosporidium spp. from adult goats in Sichuan Province, China.

Giardia duodenalis and Cryptosporidium spp. are common gastrointestinal protozoa in mammals. Many studies have been conducted on the distribution of G. duodenalis and Cryptosporidium spp. genotypes in sheep and cattle. However, in China, information about molecular characterization and genetic analysis of G. duodenalis and Cryptosporidium spp. in goats is limited. In this study, 342 fecal samples from adult goats were collected from 12 farms in Sichuan Province, China. The occurrence of G. duodenalis and Cryptosporidium spp. in adult goats was 14.9% (51/342) and 4.7% (16/342), respectively. All G. duodenalis were identified as assemblage E, with two novel genotypes (assemblages E17 and E18) being detected at the beta-giardin (bg) locus. Based on three loci-beta-giardin (bg), triose phosphate isomerase (tpi), and glutamate dehydrogenase (gdh)-multilocus sequence typing revealed three novel multilocus genotypes (MLGs) of assemblage E (MLG-E1, E2, E3 (sc)). Small Subunit (SSU) rRNA-based PCR identified two Cryptosporidium species, namely C. xiaoi (11/16) and C. suis (5/16). This study is not only the first to report C. suis infection in adult goats in China but is also the first to use the MLG approach to identify G. duodenalis in adult goats.