Frequency of Canine Parvovirus Type-2 Variants by PCR in Enteric and Healthy Dogs and Genotyping of Variants by Restriction Enzyme (RE) Mapping by DdeI Endonuclease Based on Partial VP-2 Gene Sequence

A comprehensive molecular survey of viral pathogens associated with canine gastroenteritis

Viral pathogens are the primary cause of canine gastroenteritis. However, few structured comprehensive studies on the viral etiology of canine gastroenteritis have been conducted. In this study, 475 rectal swabs collected over three years (2018-2021) from clinical canine gastroenteritis cases were screened for the presence of six major enteric viruses - canine parvovirus 2 (CPV-2), canine distemper virus (CDV), canine adenovirus 2 (CAdV-2), canine coronavirus (CCoV), canine astrovirus (CaAstV), and canine rotavirus (CRV) - by real-time PCR. The most frequently detected virus was CPV-2, which was present in 64.8% of the samples (subtype 2a, 21.1%; 2b, 77.4%; 2c, 1.5%), followed by CDV (8%), CaAstV (7.2%), CCoV (5.9%), and CAdV-2 (4.6%). Two to four of these viruses in different combinations were found in 16.8% of the samples, and CRV was not detected. The complete genome sequences of Indian isolates of CDV, CCoV, and CaAstV were determined for the first time, and phylogenetic analysis was performed. This study highlights the need for routine prophylactic vaccination with the appropriate vaccines. Notably, 70.3% of animals vaccinated with DHPPiL were found to be positive for at least one virus. Hence, regular molecular analysis of the prevalent viruses is crucial for addressing vaccination failures.

Comparison of three methods including temperature, H2O2/ascorbic acid/sonication, and nitrous acid treatments for overcoming the inhibitory effect of heparin on DNA amplification in realtime-PCR

Heparin molecules have an inhibitory effect on DNA amplification by binding to the majority of DNA-interacting proteins. Different physical, chemical, and enzymatic methods have been used to degrade and depolymerize heparins in biomedical investigations. In this study, we aimed to evaluate some heparin degradation methods to eliminate the inhibitory effect of heparin on DNA amplification. Here, we report highly efficient, simple, and convenient methods to eliminate the heparin inhibitory effect on DNA amplification by treatments including temperature, nitrous acid, and H₂O₂/ascorbic acid/sonication. Further, treatment conditions including temperature degree and duration of treatments, the concentration of ascorbic acid, and intensity of sonication were reviewed. Target DNAs were extracted using the phenol-chloroform method. DNA concentrations and purity were analyzed before and after each treatment by Nanodrop spectrophotometry. DNA amplifications were attempted using a commercially available realtime-PCR mastermix. We found that the inhibitory behavior of heparin was well eliminated after the 85 °C/2 h, 65 °C/2 h, nitrous acid (pH = 3), and H₂O₂/ascorbic acid/sonication treatments, respectively. The further analyses indicated that the application of nitrous acid in pH = 1.5 and H₂O₂/ascorbic acid/sonication in higher ascorbic acid concentrations and sonication intensities lead to failure in DNA amplification due to the degradation of target sequences. From our experience, simple heat treatments or at the next level using nitrous acid and H₂O₂/ascorbic acid/sonication have enabled the detection and quantification of virus infection in heparin blood samples. These approaches may enable researchers to utilize blood taken in heparin tubes for genome amplification and diagnostic purposes.