RESUMO
Newcastle disease (ND) causes severe economic losses in poultry production. Despite the intensive vaccination regimes of NDV in Egypt, many outbreaks are being reported. The present study focused on the preparation and evaluation of inactivated velogenic Newcastle disease virus vaccine (genotype VII) isolated from Egyptian broiler chicken during 2015-2016. Fifty-five tissue samples including trachea, lung, liver, proventriculus, intestine, and kidney collected from commercial broiler chickens were used for virus isolation in specific pathogen-free embryonated chicken eggs (ECE) and identified using RT-PCR and sequencing. The isolates were classified by sequencing as velogenic NDV genotype VIId containing F0 protein cleavage site motifs (112RRQKRF117). A selected isolate was served as a master seed for the preparation of inactivated NDV vaccine with or without Montanide ISA70 adjuvant and evaluated in SPF chicks. Nine NDV isolates were isolated on ECE and the highest infectivity titer of the virus was 7.50 log10 EID50 mL-1 by the 5th passage. Vaccinated chicks with NDV-Montanide ISA70 adjuvanted vaccine exhibited antibody titer of 5.20 log2 at the 3rd-week-post-vaccination (WPV) with the highest titer (8.90 log2 mL-1) at the 6th-WPV. Protective antibodies values were persisted to 12th WPV followed by a gradual decrease to the end of the experiment (16th weeks). Vaccination of chicks with inactivated NDV isolate without adjuvant failed to induce protective HI antibodies all over the experiment. Chickens vaccinated with the ISA70 adjuvant vaccine were passed homologous challenge tests with 100% protective efficiency, while the unadjuvanted vaccine could not provide any protective efficiency. In conclusion, the preparation of inactivated oil adjuvant vaccine from NDV field circulating strains was efficient in controlling the disease in Egypt.
RESUMO
Fish represent a worldwide significant source of animal protein. In order to investigate the prevalence of MRSA in catfish as well as the inhibitory effect of Sidr honey on virulence genes of MRSA, fish were collected from Bahr Elbaker canal at Sharkia Governorate, Egypt. Swab samples were collected under complete aseptic conditions from internal organs (pancreas, liver, kidney and intestine), gills and skin then subjected to bacteriological examination. A total of 70 S. aureus strains were isolated from catfish, out of them 15 (21.42%) strains were identified as MRSA as a first record in Egypt. PCR was used for detection of meca, coa and spa genes in the isolated MRSA strains before and after the exposure to sidr honey. Before exposure to sider honey, all the selected MRSA strains showed positive results for meca, coa and spa genes with specific amplicon size of 310 bp, 430 bp and 226 bp, respectively. After exposure to sidr honey, MRSA strains showed inhibition of coa and spa genes, but has no effect on meca gene. In addition, scanning electron microscopy was used for detection of the morphological characters of MRSA strains before and after treatment with sidr honey. After exposure of MRSA strains to 30% (w/v) Sidr honey for 48 hours, cells surfaces were observable irregular with the appearance of cell debris. In conclusion, MRSA strains could be isolated from fresh water catfish in Egypt which may be attributed to the contamination of water and fish food. Sider honey showed a significant inhibitory effect on the growth of isolated MRSA strains. Moreover, it could inhibit spa and coa genes. SEM is a valuable tool revealing the abnormal morphological changes that take place in MRSA strains after exposure to Sidr honey.
