Multilocus genotyping of Giardia duodenalis in dairy cattle in Henan, China.

Giardia duodenalis is a common and widespread intestinal protozoan parasite of both humans and animals. Previous epidemiological and molecular studies have identified Giardia infections in different animals and humans, but only limited information is available about the occurrence and genotypes of Giardia in cattle in China. In this study, we determined the occurrence of giardiasis and genetically characterized G. duodenalis in dairy cattle in Henan Province, central China. The overall prevalence of G. duodenalis was 7.2% (128/1777) on microscopic analysis, with the highest infection rate (22.7%) in calves aged less than 1 month. G. duodenalis assemblages and subtypes were identified with multilocus genotyping based on the SSU rRNA, ß-giardin (bg), glutamate dehydrogenase (gdh), and triosephosphate isomerase (tpi) genes. Two assemblages were detected in the successfully sequenced samples: assemblage A (n = 58), assemblage E (n = 21), with a mixed E and A assemblage (n = 2). Four novel subtypes of the gdh gene and seven of the bg gene were found among the G. duodenalis assemblage E isolates. Using the nomenclature for the multilocus genotype (MLG) model, nine novel multilocus genotypes E (MLGs E1-E9) and three MLGs A (a novel subtype AI, previously detected subtype AII-1, and a combination of both) were identified. MLG AII-1 identified in this study may be an important zoonotic subtype. The dairy cattle in Henan are a potential public health concern.

Genotyping and subtyping Cryptosporidium parvum and Giardia duodenalis carried by flies on dairy farms in Henan, China.

BACKGROUND: Cryptosporidium and Giardia are important causes of diarrhea diseases in humans and animals worldwide, and both of them are transmitted by the fecal-oral route, either by direct contact or by the ingestion of contaminated food or water. The role of flies in the mechanical transmission of Cryptosporidium and Giardia has been receiving increasing attention. To date, no information is available in China about the occurrence of Cryptosporidium and Giardia in flies. We here investigated Cryptosporidium and Giardia in flies on dairy farms in Henan Province, China, at the genotype and subtype levels. METHODS: Eight hundred flies were randomly collected from two dairy farms from July 2010 to September 2010 and were divided evenly into 40 batches. The fly samples were screened for the presence of Cryptosporidium and Giardia with nested PCR. Cryptosporidium was genotyped and subtyped by analyzing the DNA sequences of small subunit rRNA (SSU rRNA) and 60-kDa glycoprotein (gp60) genes, respectively. The identity of Giardia was determined by sequence analyzing of the triosephosphate isomerase (tpi), glutamate dehydrogenase (gdh), and ß-giardin (bg) genes. RESULTS: Forty batches of flies had 10% of contamination with Cryptosporidium or Giardia, with a mixed infection of the two parasites in one batch of flies. The Cryptosporidium isolates were identified as C. parvum at the SSU rRNA locus, and all belonged to subtype IIdA19G1 at the gp60 locus. The Giardia isolates were all identified as assemblage E of G. duodenalis at the tpi, gdh, and bg loci. One novel subtype of assemblage E was identified based on the gdh and bg loci. CONCLUSIONS: This is the first molecular study of Cryptosporidium and Giardia in flies identified at both genotype and subtype levels. SSU rRNA and gp60 sequences of C. parvum in flies was 100% homologous with those derived from humans, suggesting flies act as an epidemiological vector of zoonotic cryptosporidiosis. The variable PCR efficiencies observed in the analysis of Giardia at different loci suggest that we should use the multilocus genotyping tool in future studies to increase the detection rate, and importantly, to obtain more complete genetic information on Giardia isolates.

The correlation between the internal structure and vascularization of controllable porous bioceramic materials in vivo: a quantitative study.

It is noticeable that porous architectural characteristics of the biomaterials play an important role in revascularization of the scaffold. However, there has been no consensus regarding the optimal conditions for vascularization, including macropore size, shape, interconnection, and the arrangement of macropores, due to the failure to accurately control porous structure of biomaterials. To investigate the effect of the porous structure parameters on vascularization of the biomaterials, an accurate control of these parameters is required. In this study, porous ß-tricalcium phosphate (ß-TCP) with accurately controlled pore parameters is fabricated by using assembled organic microspheres as templates combined with casting technique. Using this technique, we produced a series of disk-type ß-TCP with variable pore sizes and variable interconnections to evaluate the influence of macropore size and interconnection on the vascularization of bioceramic material in vivo. The vascularization of ß-TCP implanted in the rabbit model is evaluated by histomorphology and single photon emission computed tomography. The results showed that the pore parameters affect not only the size of the blood vessels growing into the porous structure but also the number of blood vessels formed in the pores of the bioceramic. The increase in pore size only resulted in an increase in size of the blood vessels growing into the macroporous of the bioceramic scaffolds. However, with the increase in size of interconnection, both the size and number of the blood vessels formed in the macroporous increased. Therefore, we conclude that the size of the interconnections is more important for vascularization in the scaffold compared with the pore size. On the other hand, there was no significant difference in vascularization in the scaffolds with pores size above 400 µm, and there was no marked increase in extent of vascularization with further increase in pore size above 400 µm, indicating that the upper limit of pore size for vascularization is 400 µm.