Molecular typing of canine parvovirus type 2 by VP2 gene sequencing and restriction fragment length polymorphism in affected dogs from Egypt.

Introduction: Canine parvovirus-2 (CPV-2) is one of the most common infectious diseases in dogs characterized by severe gastroenteritis, vomiting, and bloody diarrhea. Little information is available about this topic in Egypt, particularly in the Delta region. This study reports the prevalence and molecular analysis of CPV-2 variants collected from El-Gharbia and Kafrelsheikh governorates in the Delta of Egypt. Methods: In this study, 320 rectal swabs were collected from infected domestic dogs from two districts in delta Egypt. The samples were investigated by rapid immunochromatographic test and polymerase chain reaction for detection the prevalence of CPV-2 variants. The genetic characterization was performed using restriction fragment length polymorphism (RFLP) analysis and partial VP2 gene sequence. Results and discussion: The viral antigen was detected in (264/320, 82.5%) of samples by IC test, while PCR was found more sensitive by detecting (272/320, 85%) positive samples. The RFLP technique using MboII restriction enzyme was successfully used for the differentiation of CPV-2c antigenic variants from CPV-2a/2b strains. Interestingly, the molecular and phylogenetic analysis revealed that both CPV-2a and CPV-2c are circulating in the study area. Deduced amino acid sequence analysis showed changes at residue (N426E) and residue (T440A).: Our results indicated that CPV-2 is prevalent among dogs in Egypt, and therefore further molecular and epidemiological studies of CPV-2 are warranted.

In vitro investigation of the antiviral activity of propolis and chitosan nanoparticles against the genotype VII Newcastle disease virus.

The Newcastle disease virus (NDV) is considered a serious threat to global poultry production. Despite the availability of vaccines, it remains a major devastating epidemic responsible for great economic losses. The development of novel virus-controlling strategies is therefore an urgent need. The present study investigated for the first time the antiviral efficacy of propolis and chitosan nanoparticles against two NDV isolates, MW881875 and MW881876, recovered from vaccinated commercial broiler farms in KafrEl Sheikh Governorate, Egypt. The polygenetic analysis focused on the F and M genes, with one isolate having a 97% identity with the genotype VII NDV Israeli strain. On the other hand, the identified isolates showed high genetic variation and only 76% identity with the LaSota vaccine (genotype II). More interestingly, the cell cytotoxic concentrations of chitosan, propolis, and a propolis-chitosan mixture against Vero cells were 327.41 ± 12.63, 109.48 ± 8.36, and 231.78 ± 11.46 µg/ml, respectively. The median tissue culture infectious dose (TCID50) assay demonstrated that the nanoparticles have antiviral effects after NDV exposure resulting in significant decrease in viral titer (TCID50) by 2, 2.66, and 2.5 log10 at 62 µg/ml of chitosan, 13 µg/ml of propolis, and 30 µg/ml of the propolis-chitosan mixture, respectively, compared with the control TCID50 value of 4 log10. Taken together, the results provide novel insights into the potentially promising roles of propolis and chitosan as novel, safe, and effective antiviral agents against NDV.