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Background Muscovy duck parvovirus (MDPV) causes high mortality and morbidity in Muscovy ducks, with the pathogenesis of the virus still unknown in many respects. Specific MDPV detection is often rife with false positive results because of high identity at the genomic nucleotide level and antigenic similarity with goose parvovirus (GPV). The objective of this study was to develop a sensitive, highly specific, and repeatable TaqMan-based real-time PCR (qPCR) assay for facilitating the molecular detection of MDPV. Results The specific primers and probe were designed based on the conserved regions within MDPVs, but there was a variation in GPVs of the nonstructural (NS) genes after genetic comparison. After the optimization of qPCR conditions, the detection limit of this qPCR assay was 29.7 copies/μl. The assay was highly specific for the detection of MDPV, and no cross-reactivity was observed with other non-targeted duck-derived pathogens. Intra- and inter-assay variability was less than 2.21%, means a high degree of repeatability. The diagnostic applicability of the qPCR assay was proven that MDPV-positive can be found in cloacal swabs samples, Muscovy duck embryos and newly hatched Muscovy ducklings. Conclusions Our data provided incidents that MDPV could be possible vertically transmitted from breeder Muscovy ducks to Muscovy ducklings. The developed qPCR assay in the study could be a reliable and specific tool for epidemiological surveillance and pathogenesis studies of MDPV.

Background In China, Newly emerging duck reovirus (NDRV) variants have been causing major disease problems in cherry valley ducks. NDRV has the potential to cause high morbidity and 5–50% mortality rates. Severe hemorrhagic-necrosis in the liver and spleen were commonly seen in NDRV affected ducks. The availability of upgraded methods for rapid diagnosis of newly emerging DRV variants is crucial for successful DRV infection control and prevention. Results In this study, we present a TaqMan-based real-time PCR assay (RT-qPCR) for the detection of NDRV infection. Using the conserved regions within the NDRV genome, we designed the specific primers and probe. The lower limit of detection for NDRV infection was 10 copies/μL (Ct values: 38.3) after the optimization of the RT-qPCR conditions. By cross-checking with other duck viral pathogens, no cross-reactivity was observed confirming the assay was highly specific for the detection of NDRV. Reproducibility of the RT-qPCR was confirmed by intra- and inter-assay variability was less than 2.91%(Intra-assay variability of Ct values: 0.07–1.48%; Interassay variability of Ct values: 0.49–2.91%). This RT-qPCR and conventional PCR (cPCR) detected one hundred and twenty samples of NDRV infection from different regions. The result shows that the positive rates were 94.17 and 84.17% respectively. The detection rate of RT-qPCR rapid detection assay was 10% higher than that of the cPCR method. Conclusion This research developed a highly sensitive, specific, reproducible and versatile of RT-qPCR for quantitatively detecting NDRV. It can be used to study the pathogenesis and epidemiology investigation of NDRV.

Background Morbilliviruses are categorized under the family of Paramyxoviridae and have been associated with severe diseases, such as Peste des petits ruminants, canine distemper and measles with evidence of high morbidity and/or could cause major economic loss in production of livestock animals, such as goats and sheep. Feline morbillivirus (FeMV) is one of the members of Morbilliviruses that has been speculated to cause chronic kidney disease in cats even though a definite relationship is still unclear. To date, FeMV has been detected in several continents, such as Asia (Japan, China, Thailand, Malaysia), Europe (Italy, German, Turkey), Africa (South Africa), and South and North America (Brazil, Unites States). This study aims to develop a TaqMan real-time RT-PCR (qRT-PCR) assay targeting the N gene of FeMV in clinical samples to detect early phase of FeMV infection. Results A specific assay was developed, since no amplification was observed in viral strains from the same family of Paramyxoviridae , such as canine distemper virus (CDV), Newcastle disease virus (NDV), and measles virus (MeV), and other feline viruses, such as feline coronavirus (FCoV) and feline leukemia virus (FeLV). The lower detection limit of the assay was 1.74 × 10 4 copies/μL with Cq value of 34.32 ± 0.5 based on the cRNA copy number. The coefficient of variations (CV) values calculated for both intra- and inter-assay were low, ranging from 0.34–0.53% and 1.38–2.03%, respectively. In addition, the clinical sample evaluation using this assay showed a higher detection rate, with 25 (35.2%) clinical samples being FeMV-positive compared to 11 (15.5%) using conventional RT-PCR, proving a more sensitive assay compared to the conventional RT-PCR. Conclusions The TaqMan-based real-time RT-PCR assay targeting the N gene described in this study is more sensitive, specific, rapid, and reproducible compared to the conventional RT-PCR assay targeting the N gene, which could be used to detect early infection in cats.