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Ranaviruses are globally emerging pathogens causing mass mortality in both farmed and wild populations. In this study, we confirmed that a novel ranavirus was related to mass die‐offs of black‐spotted pond frogs (Rana nigromaculata) in Sichuan Province, China. Histological examination revealed marked degeneration or necrosis in parenchymatous organs, and intracytoplasmic inclusions can be observed in the liver and intestine cells. The virus was isolated from diseased tadpoles (tentatively named the virus as RNRV), and the ranavirus‐like particles could be observed in infected EPC cells by the electron microscope. The tadpoles challenged with the isolated virus displayed similar clinical symptoms and pathogenicity as those naturally infected. Physicochemical characteristics showed that it was sensitive to chloroform treatment, trypsin treatment, heating treatment, acidity and alkalinity. Biological characteristics showed that RNRV can induce cytopathic effect (CPE) in various fish cell lines and the optimum growth temperature is 25~28°C. In addition, the complete genome sequence of RNRV was determined (GenBank accession number MG791866) and analysed. The results showed that the genome of RNRV consists of 104,286 bp containing 55.2% GC content and 104 predicted ORFs were identified in the genome. Phylogenetic analysis of the complete genome revealed that RNRV should belong to the FV3‐like group in genus Ranavirus, and is more closely related to RGV and STIV. These studies confirmed that the RNRV was the causative agent of this natural epizootic event and genome analysis indicated that it belongs to the FV3‐like group. In addition, viral physicochemical and biological characteristics will provide a scientific basis for prevention and control. [ABSTRACT FROM AUTHOR]

An aberrant Ascaris suum infection in a domestic dog in China in 2019 is described for the first time. This pathogen is a common roundworm of pigs with few reported cases in domestic animals. Our findings suggest a wider infection range with a possible transmission of A. suum to domestic animals that interact with humans. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Toxascaris leonina (Nematoda, Ascarididae) is a cosmopolitan nematode of canids and felids and poses potential threats to public health due to aberrant larva migrans. Herein, the complete mitochondrial genome sequence of a representative of this nematode from the dog in China was determined using next-generation sequencing technology. The assembled genome was 14,357 bp in length and encoded 36 genes, including 12 protein-coding genes, 22 transfer RNAs and 2 ribosomal RNAs. The phylogeny revealed that the canid-originated T. leonina were phylogenetic distinctiveness from the felid-originated T. leonina within the genus Toxascaris of Ascarididae, supporting that T. leonina may represent a species complex. [ABSTRACT FROM AUTHOR]

The plerocercoid larvae (spargana) of Spirometra decipiens (Cestoda: Diphyllobothriidae) can parasitize humans, causing the zoonotic sparganosis. In this study, the complete mitochondrial genome of this tapeworm was determined using an Illumina sequencing platform. The entire genome was 13,642 bp in length and contained 12 protein-coding genes, 22 transfer RNAs, two ribosomal RNAs, and two non-coding regions. The phylogeny indicated that S. decipiens was closely related to Spirometra erinaceieuropaei and supported the monophyletic relationships between Spirometra, Diphyllobothrium, and Diplogonoporus within the Dipyllobothriidae. These results should contribute to a better understanding of the phylogenetic position of this species. [ABSTRACT FROM AUTHOR]

Ranaviruses were recognized as important pathogens from the late 1990s, which are global pathogens that have continued to severely threaten aquaculture and wildlife worldwide. In this study, we report an infection with a CMTV-like ranavirus in cultured Percocypris pingi (P. pingi), a rare fish species that originated in upper Yangtze River system of China. Naturally and experimentally infected fish exhibited body surface ulcers and enlarged spleen and kidney. Histological examination revealed intracytoplasmic inclusions in the liver, spleen and kidney. Meanwhile, hexagonal viral arrays were observed in cytoplasm of infected Epithelioma papulosum cyprini (EPC) cells. Animal experimental trials confirmed that this hexagonal virus, named P. pingi ranavirus (PPRV), was the causative agent. PPRV (Accession no. ON080858) contains a 106.7 kbp genome, with a GC content of 55.03% and 97 ORFs. The results of phylogenetic analysis of the complete genome and dot plot comparisons both confirmed that the virus was classified into the CMTV-like group. Phylogenetic analyses based on MCP, mMMP, DNA polymerase and ribonuclease III genes indicated that PPRV shared the nearest relationship to Triplophysa siluorides ranavirus (Accession no. FYL140220), Chinese giant salamander iridovirus (Accession no. KF512820) and Andrias davidianus ranavirus (Accession no. KF033124), which were from China. Amidst the expanding fish host range of CMTV-like ranaviruses, this is the first report of ranavirus infection in P. pingi. • This is the first report of ranavirus infection in Percocypris pingi , and the ranavirus is a new member of the CMTV-like ranaviruses. • This study reports a new case of CMTV-like ranavirus infection in fish. • Our study will provide significative information for subsequent studies on the transmission of members of the CMTV-like ranavirus clade between fish and amphibians. [ABSTRACT FROM AUTHOR]

An ulcerative disease of largemouth bass has severely damaged Chinese largemouth bass industry for years. Here, we investigated prevalence of this disease in southwest China and typical cases from 2016 to 2018 were presented. All diseased fish behaved lethargic and inappetent; skin and muscles were severe hemorrhage, ulceration and inflammation; liver, spleen and kidney were necrosis. All cases were proved to relate to the ranavirus infection by PCR detection and pathogen isolation. We observed plenty of hexagonal particles in effected epithelioma papulosum cyprinid. Experimental trials convinced that LMBV-like was the causative agent. Phylogenetic analysis bases on major capsid gene exhibited the distinction between Asian and Euramerica isolates. Further sequence analysis revealed 16 nucleotides mutant which lead to 3 amino acid changes of all Asian strains. In summary, the identification of the pathogen of largemouth bass ulcerative disease in southwest China is essential for the detection and vaccine development, which is vital important for this disease control. • We revealed that the severe largemouth bass ulcerative disease in southwest China is related to LMBV-like infection. • Multiple sequences alignment of complete MCP gene revealed that sixteen nucleotides and three amino acids of LMBV-like strains in this study and other Asian strains were inconsistent with that of corresponding positions of Euramerican strains • Based on phylogenetic analysis, a new group of Santee-cooper Ranavirus was proposed which distributed in Asia and possess larger range of hosts including some cyprinid and perciform fish. [ABSTRACT FROM AUTHOR]

Sichuan, located in the upper reaches of the Yangtze River, is the gathering place of many rivers and plays an important role in sturgeon aquaculture and wild sturgeon protection in China, where it suffered the severe influence of Streptococcus iniae infection in sturgeon. However, the annual thousands of tons of antibiotic usage in Sichuan may accumulate in water and cause obstacles to the prevention of S. iniae infection. In contrast, the regional antibiotic resistance characteristics have been rarely unknown. Seventeen S. iniae strains were collected from the major sturgeon culture areas in Sichuan, and the genotyping and the distribution of antibiotic resistance profiles (ARPs) and genes (ARGs) of S. iniae were established in this study. The results showed that the isolates could be divided into four subtypes by pulsed-field gel electrophoresis analysis. Besides, most isolates showed multiple resistance to the antibiotic such as amikacin, neomycin, enrofloxacin, lincomycin, and sulfamethoxazole. Also, sturgeon-derived S. iniae has a relatively low similarity with other fish-derived S. iniae in the world but high similarity with three animal-derived pathogens from Sichuan in previous studies. Moreover, a total of 37 ARGs were detected positively based on 95 ARGs detection, in which aac(6')-Ib(aka aacA4)-01, aac(6')-Ib(aka aacA4)-02, aadA1, floR, blaTEM, sulA/folP-03, and tetA-02 were most prevalent. Our study indicated that the ARGs of sturgeon-derived S. iniae were significantly enhanced compared with the ATCC29178 strains and have a risk of accessing more ARGs from other bacteria in water in Sichuan. This study claimed that sturgeon has a potential risk in the prevention and control of Streptococcosis in Sichuan, the upper reaches of Yangtze River, based on the antibiotic resistance analysis of S. iniae, and it may also increase the risk of highly resistant S. iniae transmission into the middle and lower reaches., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Senescence in mesenchymal stem cells (MSCs) not only hinders the application of MSCs in regenerative medicine but is also closely correlated with biological aging and the development of degenerative diseases. In this study, we investigated the anti-aging effects of curcumin (Cur) on canine bone marrow-derived MSCs (cBMSCs), and further elucidated the potential mechanism of action based on the modulation of autophagy. cBMSCs were expanded in vitro with standard procedures to construct a cell model of premature senescence. Our evidence indicates that compared with the third passage of cBMSCs, many typical senescence-associated phenotypes were observed in the sixth passage of cBMSCs. Cur treatment can improve cBMSC survival and retard cBMSC senescence according to observations that Cur (1 μM) treatment can improve the colony-forming unit-fibroblasts (CFU-Fs) efficiency and upregulated the mRNA expression of pluripotent transcription factors (SOX-2 and Nanog), as well as inhibiting the senescence-associated beta-galactosidase (SA-β-gal) activities and mRNA expression of the senescence-related markers (p16 and p21) and pro-inflammatory molecules (tumor necrosis factor-α ( TNF-α ) and interleukin-6 (IL-6)). Furthermore, Cur (0.1 μM~10 μM) was observed to increase autophagic activity, as identified by upregulation of microtubule-associated protein 1 light chain 3 (LC3), unc51-like autophagy-activating kinase-1 (ULK1), autophagy-related gene ( Atg) 7 and Atg12, and the generation of type II of light chain 3 (LC3-II), thereby increasing autophagic vacuoles and acidic vesicular organelles, as well as causing a significant decrease in the p62 protein level. Moreover, the autophagy activator rapamycin (RAP) and Cur were found to partially ameliorate the senescent features of cBMSCs, while the autophagy inhibitor 3-methyladenine (3-MA) was shown to aggravate cBMSCs senescence and Cur treatment was able to restore the suppressed autophagy and counteract 3-MA-induced cBMSC senescence. Hence, our study highlights the important role of Cur-induced autophagy and its effects for ameliorating cBMSC senescence and provides new insight for delaying senescence and improving the therapeutic potential of MSCs., Competing Interests: All the authors declared no conflict of interest.

Nocardia seriolae is the causative agent of nocardiosis in both marine and freshwater fish. Here, we report on multiple outbreaks of nocardiosis associated with elevated mortality (23-35%) in farmed largemouth bass in Sichuan, China, from 2017 to 2018. A total of 9 strains isolated from diseased largemouth bass were identified as N. seriolae by phenotypic characterization, 16S rRNA and hsp65 gene sequence analysis. The clinical signs of infected largemouth bass included hemorrhage, skin ulcers and prominent tubercles varying in size in the gill, liver, spleen and kidney. Experimental infection indicated that these isolates were the pathogens responsible for the mortalities. In vitro antibacterial activities of 12 antibiotics against N. seriolae isolates were determined as minimum inhibitory concentrations. Histopathological observation of diseased fish infected with N. seriolae showed necrotizing granulomatous hepatitis, nephritis, splenitis, epithelial hypertrophy and hyperplasia with degenerative changes of the epithelium in the gill. Large quantities of bacterial aggregates were found in the necrotic area of the granuloma by Lillie-Twort Gram stain and immunocytochemistry. Our findings indicated that N. seriolae is a serious threat to the largemouth bass Micropterus salmoides industry in Southwest China.

Acinetobacter lwoffii, a serious human pathogen, has been identified as a cause of nosocomial infections such as bacteremia, pneumonia and meningitis. There are only a few studies reporting A. lwoffii as a pathogen of fish. During 2016 and 2017, six bacterial strains, isolated from diseased fish of the Schizothorax genus, were identified as A. lwoffii by morphology, biochemical tests, 16S rDNA and gyrB gene sequencing analysis. One of these isolates was selected for experimental infection of Sclizothorax prenanti, Schizothorax davidi and Schizothorax wangchiachii, to confirm its pathogenicity. Experimentally infected fish showed similar symptoms to those observed in fish after natural outbreaks. Susceptibility of the isolates to 14 antibiotics was tested using a disc diffusion method; all isolates were resistant to cephalothin, aminoglycosides and β-lactams, and sensitive only to some fluoroquinolones and tetracyclines. Histological examination revealed that A. lwoffii infection could cause pathological lesions in multiple organs and tissues, especially in liver, kidney, spleen and heart. These lesions included extensive haemorrhage, vacuolar degeneration, necrosis and inflammatory cell infiltration. To our knowledge, this is the first report on A. lwoffii as a virulent pathogen for fish of the Schizothorax genus., (© 2018 Blackwell Verlag GmbH.)

Background: Enterocytozoon bieneusi, the most commonly identified microsporidian species in humans, is also identified in livestock, birds, rodents, reptiles, companion animals, even wastewater. However, there is no information available on occurrence of E. bieneusi in pet chipmunks. The aim of the present study was to determine the genotypes, molecular characterization of E. bieneusi in pet chipmunks, and assess the zoonotic potential., Results: A total of 279 fecal specimens were collected from chipmunks from seven pet shops and one breeding facility in Sichuan province, China. The prevalence for E. bieneusi was 17.6% (49/279) based on nested PCR targeting the internal transcribed spacer (ITS) region. The prevalence of E. bieneusi in chipmunks < 90 days of age was significantly higher than that in older chipmunks; however, differences among different sources and between genders were not significant. Eight genotypes of E. bieneusi were identified, including four known genotypes (D, Nig7, CHG9, and CHY1) and four novel genotypes (SCC-1 to 4). Phylogenetic analysis classified these genotypes into four distinct groups as follows: genotypes D and CHG9 clustered into group 1 of zoonotic potential; genotypes Nig7 and CHY1 clustered into group 6 and a new group, respectively; the four novel genotypes (SCC-1 to 4) formed a separate group named group 10., Conclusions: To the best of our knowledge, this is the first study reporting the prevalence and genotypes of E. bieneusi in pet chipmunks in China. Genotypes D and Nig7, found in chipmunks in this study, have also been previously identified in humans, which suggests that chipmunks might play a role in the transmission of this pathogen to humans.