Prevalence, Diagnosis, and Vaccination Situation of Animal Chlamydiosis in China

Since the first case of Chlamydia infection in duck had been reported in 1956 and the first case from domestic animal had been reported in 1979 in China, the chlamydia prevalence in China was heavily according to the published data. The Chlamydia in avian prevalence has been reported at least 11 provinces, Chlamydia in sheep and goats at least 11 provinces, in swine at least 15 provinces, in cows at least 13 provinces and in yaks at least 5 provinces with result of IHA detection. Different diagnostic method such as CFT, ELISA and ABC-ELISA (avidin-biotin-complex ELISA) had been established besides IHA. The inactivated vaccines have been developed with isolated strains from sheep, goats, swine and cows. These inactivated vaccines have been used since 1980s and Chlamydia prevalence in China has been successfully controlled in domestic animal. However, the inactivated vaccines of Chlamydia isolated from avian species have not been successful, although a series of experimental vaccine have been done. Due to the unsustainable eradication plan of Chlamydia in China, sporadic outbreak in animal would happen if the vaccinations were suspended and economy lose in some farmers. Although Chlamydia prevalence in China has a long history, however, almost all published studies are in Chinese, which, in some degree, blocked scientists in other countries to understand the prevalence situation and control measures of Chlamydia in China

Differential diagnosis of Moniezia benedeni and M. expansa (Anoplocephalidae) by PCR using markers in small ribosomal DNA (18S rDNA)

Moniezia benedeni and M. expansa are common ruminant tapeworms of worldwide distribution, causing gastrointestinal disorders and even death in sheep and goats. In this study, a polymerase chain reaction- (PCR-) based approach for precise species identification was developed and also applied to faecal DNA diagnosis of the tapeworm infection. Since nuclear ribosomal DNA (rDNA) appears to be a useful target for species and/or strain markers, the 18S regions of the rDNA of M. benedeni and M. expansa were amplified and sequenced. The lengths and GC contents of the regions sequenced were 2476–2487 bp and 51.9–52.1% for M. benedeni and 2473 bp and 51.9–52.0% for M. expansa, respectively. Alignment and comparison of the 18S sequences of the two species showed 92.5–93.3% homology. No matches for the 18S regions of M. benedeni and M. expansa were found with other species by BLAST search, which made the 18S sequences appropriate markers for the design of distinctive primers for the two Moniezia species. Our 18S-based PCR could detect as low levels as 0.5 pg genomic DNA or the DNA extracted from 0.2 g faecal sample collected from the rectum of an M. expansa-infected goat. The results indicate that this PCR approach is a reliable alternative for the differential diagnosis of Moniezia species in faecal samples

First Report of Chlamydia abortus in Farmed Fur Animals

Chlamydia (C.) abortus, a globally distributed obligate intracellular bacterium, has attracted increasing interest according to its veterinary importance and zoonotic nature. C. abortus can infect a variety of animals and cause foetal loss in livestock resulting in economic loss. In this study, the samples collected from two farms of foxes (n=20), raccoon dogs (n=15) and minks (n=20), were investigated by Chlamydiaceae- and Chlamydia species-specific real-time PCR. The results showed that all the tested foxes (20/20) and raccoon dogs (15/15) harbored Chlamydia spp., while 5% of minks (1/20) were positive for Chlamydia spp. C. abortus was identified in all positive samples as the dominant Chlamydia species, with C. pecorum DNA coexistence in some of the rectal samples (7/20) taken from foxes. Phylogenetic analysis based on specific gene fragments of 16S rRNA, IGS-23S rRNA, and ompA revealed that all sequences obtained in this study were assigned to the Chlamydiaceae family with high similarity to C. abortus S26/3 and B577 previously identified in ruminants. This is the first report confirming that farmed foxes, raccoon dogs, and minks carry C. abortus. Further studies are needed to fully elucidate the epidemiology and pathogenicity of this pathogen in farmed fur animals as well as the potential risks to public health

Three-dimensional hepatocyte culture system for the study of <i>Echinococcus multilocularis</i> larval development

<div><p>Background</p><p>Hepatocyte-based metacestode culture is an attractive method to study alveolar echinococcosis (AE), but it is limited by the relatively short lifespan of cultured hepatocytes in maintaining their normal function.</p><p>Methodology/principal findings</p><p>We describe a three-dimensional (3D) hepatic culture system developed from co-cultured hepatocytes and mesenchymal stem cells using a collagen scaffold to study the development of <i>Echinococcus multilocularis</i> larvae. This 3D culture system preserved the function of hepatocytes for a longer period of time than their monolayer counterparts, with albumin secretion, 7-ethoxyresorufin O-deethylation activity, urea synthesis, CYP3A4 and CYP2D6 activity being highly preserved for 21–28 days. The expression levels of hepatocyte-specific genes including CLDN-3, Bsep, AFP, G6P, A1AT, CYP3A4 and NR1I3 were significantly higher in the 3D cultured system compared with their monolayer counterparts after 14-days in culture. Additionally, in the presence of 3D cultured hepatocytes, 81.2% of <i>E</i>. <i>multilocularis</i> protoscoleces rapidly de-differentiated into infective vesicles within eight weeks. Transcriptomic analyses revealed 807 differentially expressed genes between cultured vesicles and protoscoleces, including 119 genes uniquely expressed in protoscoleces, and 242 genes uniquely expressed in vesicles. These differentially expressed genes were mainly involved in parasite growth relating to the G-protein coupled receptor activity pathway, substrate-specific transmembrane transporter activity, cell-cell adhesion process, and potentially with neuroactive ligand-receptor interaction.</p><p>Conclusions/significance</p><p>This culture system provides a valuable advance in prolonging hepatocyte functionality, a foundation for future in-depth analysis of the host-parasite interaction in AE, and a useful model to evaluate potential therapeutic strategies to treat AE.</p></div

Viability assay of 3D cultured cells.

<p>(A-D) A set of FDA-PI double-staining fluorescent images of cells in Hepatocytes (3D) groups after culture for 7, 14, 21, and 28 days. (E-H) A set of FDA-PI double-staining fluorescent images of cells in Hepatocytes-MSCs (3D) groups after culture for 7, 14, 21, and 28 days. Live cells are stained green, and dead cells are stained red.</p

Three-dimensional hepatocyte culture system for the study of <i>Echinococcus multilocularis</i> larval development - Fig 6

<p>Mouse anatomy after the intraperitoneal injection of protoscoleces (A-C, control group) or vesicles (D-F, co-culture group) after one, two, and three months, scale bar: 5 mm. Microscopic analysis of hematoxylin and eosin staining pictures of metacestode tissue corresponding to A-F, respectively (A’-F’), scale bar: 100 μm. During the proliferative phase, the <i>E</i>. <i>multilocularis</i> metacestodes (white arrow) emerge from tissue blocks. Hematoxylin and eosin staining shows tissue infiltrates of <i>E</i>. <i>multilocularis</i> metacestodes, which are composed of fluid-filled microvesicles. The red arrows indicate the laminated layer (LL) of the larvae. The differentiation into protoscoleces (p) commences with the formation of brood capsules (BC) (C’, F’). Compared with the co-culture group, the AE metacestode lesion of the control group is composed of smaller numbers of microvesicles that contain fewer protoscoleces.</p

Volcano plot of 807 differentially expressed genes between the cultured vesicles and protoscoleces.

<p>Among these, 165 genes were up regulated and 642 were down regulated. The y-axis corresponds to the mean expression value of the log10 (p-value), and the x-axis displays the log two-fold change value. The red dots represent the significantly differentially expressed transcripts (p< 0.05); the blue dots represent the transcripts whose expression levels did not reach statistical significance (p> 0.05) between the vesicles and protoscoleces.</p