Occurrence and genetic characterization of Enterocytozoon bieneusi in pet dogs in Yunnan Province, China.

Enterocytozoon bieneusi is the most common microsporidian species in humans and can affect over 200 animal species. Considering possible increasing risk of human E. bieneusi infection due to close contact with pet dogs and identification of zoonotic E. bieneusi genotypes, 589 fresh fecal specimens of pet dogs were collected from Yunnan Province, China to determine the occurrence of E. bieneusi, characterize dog-derived E. bieneusi isolates, and assess their zoonotic potential at the genotype level. Enterocytozoon bieneusi was identified and genotyped by PCR and sequencing of the internal transcribed spacer (ITS) region of the ribosomal RNA (rRNA) gene. Twenty-nine specimens (4.9%) were positive. A statistical difference was observed in occurrence rates of E. bieneusi in pet dogs among 11 sampling sites by Fisher's exact test. Fifteen genotypes were identified and all of them phylogenetically belonged to zoonotic group 1, including four known genotypes (EbpC, D, Peru 8, and Henan-III) and 11 novel genotypes. Genotype Henan-III was reported in dogs for the first time. The finding of known genotypes found previously in humans and novel genotypes falling into zoonotic group 1 indicates that dogs may play a role in the transmission of E. bieneusi to humans in the investigated areas.

Title: Occurrence et caractérisation génétique d'Enterocytozoon bieneusi chez les chiens de compagnie dans la province du Yunnan, Chine. Abstract: Enterocytozoon bieneusi est l'espèce de microsporidies la plus répandue chez l'homme et peut affecter plus de 200 espèces animales. Compte tenu du risque accru possible d'infection humaine à E. bieneusi en raison d'un contact étroit avec des chiens de compagnie et de l'identification de génotypes zoonotiques d'E. bieneusi, 589 échantillons fécaux frais de chiens de compagnie ont été collectés dans la province du Yunnan, en Chine, pour déterminer la présence d'E. bieneusi, caractériser les isolats obtenus de chiens, et évaluer leur potentiel zoonotique au niveau du génotype. Enterocytozoon bieneusi a été identifié et génotypé par PCR et séquençage de la région d'espacement transcrit interne (ITS) du gène de l'ARN ribosomal (ARNr). Vingt-neuf échantillons (4,9%) étaient positifs. Une différence statistique a été observée dans les taux de présence d'E. bieneusi chez les chiens de compagnie parmi 11 sites d'échantillonnage par le test exact de Fisher. Quinze génotypes ont été identifiés et tous appartenaient phylogénétiquement au groupe zoonotique 1, dont quatre génotypes connus (EbpC, D, Peru 8 et Henan-III) et 11 nouveaux génotypes. Le génotype Henan-III est signalé pour la première fois chez le chien. La découverte de génotypes connus précédemment trouvés chez l'homme et de nouveaux génotypes appartenant au groupe zoonotique 1 indique que les chiens peuvent jouer un rôle dans la transmission d'E. bieneusi aux humains dans les zones étudiées.

Molecular characterization and zoonotic potential of Cryptosporidium spp. and Giardia duodenalis in humans and domestic animals in Heilongjiang Province, China.

BACKGROUND: Cryptosporidiosis and giardiasis are significant parasitic diseases shared between humans and domestic animals. Due to the close contact between humans and domestic animals in rural areas, it is important to consider the potential transmission of zoonotic parasites from infected domestic animals to humans. This investigation aimed to determine the prevalence and molecular characteristics of Cryptosporidium spp. and Giardia duodenalis in domestic animals and villagers. METHODS: A total of 116 fecal samples from villagers and 686 fecal samples from domestic animals in Heilongjiang Province, China, were analyzed for two parasites using nested polymerase chain reaction (PCR) targeting various genetic loci and DNA sequence analysis of the PCR products. RESULTS: By sequence analysis of the SSU rRNA gene, the prevalence of Cryptosporidium in humans was 0.9% (1/116), with one species of C. parvum (n = 1) detected; among domestic animals, the prevalence was 2.6% (18/686), with five species identified: C. suis (n = 7) and C. scrofarum (n = 7) in pigs, C. meleagridis (n = 1) in chickens, C. andersoni (n = 1) in cattle, and C. canis (n = 2) in foxes. C. parvum and C. canis were further subtyped as IIdA19G1 and XXa4 on the basis of gp60 gene. Regarding G. duodenalis, based on the SSU rRNA, bg, gdh, and tpi genes, the prevalence in domestic animals was 5.1% (31/608), with three assemblages identified: A (n = 1) in pigs, D (n = 1) in foxes, and E (n = 27) in geese, cattle, pigs, ducks, and sheep, along with mixed infection of A + E (n = 1) in one pig and B + E (n = 1) in one sheep. No G. duodenalis was detected in humans (0/116). CONCLUSIONS: The present results show that no overlap of subtypes between animals and villagers was found in Cryptosporidium spp. and G. duodenalis, indicating a minor role of domestic animals in infecting humans in this population. However, the presence of zoonotic protozoa in domestic animals highlights the need for special attention to high-risk individuals during close contact with domestic animals.

Itemized determination of As, Sb, Bi, Se, and Ge in graphite sample by HG-AFS with high-temperature microwave digestion.

In this paper, we optimized a method for fast and accurate determination of five impurity elements (As, Sb, Bi, Se, and Ge) in graphite samples to overcome the shortcomings of existing methods, such as complicated equipment, cumbersome process, multiple-time preparation, separate determination, and large error in results. Graphite samples were digested with HNO3-H2SO4-HClO4-HF in a high-temperature and high-pressure microwave digestion apparatus, and the elements were extracted and determined separately by AFS (atomic fluorescence spectrometry). There is no element loss during the processing and analysis of this method. The spike recoveries (As: 90.30%-102.3%, Sb: 90.73%-110.0%, Bi: 90.00%-99.67%, Se: 93.33%-110.0%, Ge: 92.26%-104.2%) and precision (RSD%; As: 1.34%-8.96%, Sb: 2.67%-7.10%, Bi: 1.83%-4.58%, Se: 0.36%-3.25%, Ge: 4.41%-8.65%) meet the requirements of the corresponding quality specifications. The method has some advantages (such as no elemental loss, fast testing, strong element targeting, and accurate results), and thus can achieve batch determination of graphite samples. The optimized method for graphite sample and final solution preparations can be used for diverse spectrometric technologies, and that for spectrometer conditions have reference value for HG-AFS instruments.