Correction: Establishment and application of a quadruple real-time RT-PCR for detecting avian metapneumovirus.

[This corrects the article DOI: 10.1371/journal.pone.0270708.].

Reverse transcription recombinase-aided amplification assay for H5 subtype avian influenza virus.

BACKGROUND: The H5 subtype avian influenza virus (AIV) has caused huge economic losses to the poultry industry and is a threat to human health. A rapid and simple test is needed to confirm infection in suspected cases during disease outbreaks. METHODS: In this study, we developed a reverse transcription recombinase-aided amplification (RT-RAA) assay for the detection of H5 subtype AIV. Assays were performed at a single temperature (39 °C), and the results were obtained within 20 min. RESULTS: The assay showed no cross-detection with Newcastle disease virus or infectious bronchitis virus. The analytical sensitivity was 103 RNA copies/µL at a 95% confidence interval according to probit regression analysis, with 100% specificity. Compared with published reverse transcription quantitative real-time polymerase chain reaction assays, the κ value of the RT-RAA assay in 420 avian clinical samples was 0.983 (p < 0.001). The sensitivity for avian clinical sample detection was 97.26% (95% CI, 89.56-99.52%), and the specificity was 100% (95% CI, 98.64-100%). CONCLUSIONS: These results indicated that our RT-RAA assay may be a valuable tool for detecting H5 subtype AIV.

Establishment and application of a quadruple real-time RT-PCR for detecting avian metapneumovirus.

In order to develop an appropriate method for high-throughput detection of avian metapneumovirus, a quadruple real-time reverse-transcription polymerase chain reaction assay was established with four pairs of specific primers and four specific probes based on the G or M gene of aMPV-A, aMPV-B, aMPV-C and aMPV-D. Its specificity and sensitivity were evaluated, and clinical samples were tested by the method. The results showed that all the four subgroups of avian metapneumovirus can be detected in the quadruple real-time RT-PCR assay simultaneously, with a detection limit of 100-1000 cRNA copies/reaction. The other common poultry viruses were negative. In the avian clinical sample detection, 39 out of 1920 clinical samples collected from 8 provinces were positive. Compared with published RT-PCR assays, the κ value of the quadruple real-time RT-PCR assay in 1920 avian clinical samples was 1.000 (P < 0.001). The established method could be used for the rapid detection of the four subgroups of avian metapneumovirus with high specificity and high sensitivity.

Traceable surveillance and genetic diversity analysis of coronaviruses in poultry from China in 2019.

Coronavirus disease 2019 (COVID-19), caused by Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first reported in Wuhan, China, and rapidly spread throughout the world. This newly emerging pathogen is highly transmittable and can cause fatal disease. More than 35 million cases have been confirmed, with a fatality rate of about 2.9% to October 9, 2020. However, the original and intermediate hosts of SARS-CoV-2 remain unknown. Here, 3160 poultry samples collected from 14 provinces of China between September and December 2019 were tested for SARS-CoV-2 infection. All the samples were SARS-CoV-2 negative, but 593 avian coronaviruses were detected, including 485 avian infectious bronchitis viruses, 72 duck coronaviruses, and 36 pigeon coronaviruses, with positivity rates of 15.35%, 2.28%, and 1.14%, respectively. Our surveillance demonstrates the diversity of avian coronaviruses in China, with higher prevalence rates in some regions. Furthermore, the possibility that SARS-CoV-2 originated from a known avian-origin coronavirus can be preliminarily ruled out. More surveillance of and research into avian coronaviruses are required to better understand the diversity, distribution, cross-species transmission, and clinical significance of these viruses.

[Correlations of extrocellular matrix metalloproteinase inducer and microvessel density to invasiveness of ameloblastoma].

BACKGROUND & OBJECTIVE: Matrix metalloproteinases (MMPs) are involved in local invasion of ameloblastomas. This study was to evaluate the role of matrix metalloproteinase inducer (EMMPRIN) in angiogenesis in ameloblastomas by analyzing EMMPRIN expression and microvessel density (MVD) in ameloblastomas and odontogenic cysts. METHODS: EMMPRIN expression and MVD in 41 specimens of ameloblastoma and 40 specimens of odontogenic cyst were examined by SP immuno-histochemistry. RESULTS: EMMPRIN was detected in all specimens of ameloblastomas and odontogenic cysts. The strong positive rate of EMMPRIN was significantly higher in ameloblastomas than in odontogenic cysts (85.4% vs. 62.5%, P<0.05). MDV was positively correlated to EMMPRIN expression to some extent (r=0.677, P<0.01). CONCLUSION: EMMPRIN may play an important role during the progression of ameloblastoma via controlling angiogenesis and degradation of extracellular MMPs.

Cellular toxic effects of combination of low dose of cisplatin and interstitial injection of 32P glass microspheres on mouse solid tumor S180.

BACKGROUND: Although 32P-glass microspheres (32P-GMS) have been used in internal radiotherapy for malignant tumors, it has been one of the key obstacles to improve the effect of radiotherapy. We investigated the cellular and hypersensitive effect of combined use of low dose of cisplatin and interstitial injection of 32P-GMS on mouse solid tumor S180. METHODS: The mice with solid tumor S180 were randomly divided into four groups (controls, cisplatin therapy, 32P-GMS therapy and combination therapy). The specimens of the mice were sectioned two weeks after treatment and weighed. The death rate of tumor cells and the inhibition rate of tumor were calculated respectively. The cell cycle and apoptosis rate were evaluated with flow-cytometry. The ultrastructural changes of the four groups were observed by a transmission electron microscope. The data were analyzed by the chi-square test. RESULTS: The growth of tumor was slower in the combination therapy group than in the simple therapy groups by macrography. The inhibition rate and the death rate of tumor cells of the combination therapy group were significantly higher than those of the control group and the other two simple therapy groups (P < 0.05). More cell damages were displayed in the combination therapy group than in the other groups under the light and electronic microscope. CONCLUSION: Low-dose cisplatin combined with interstitial injection of 32P glass microspheres could be used as an effective hypersensitive regimen for the internal radiotherapy of mouse solid tumor S180.