Detection of antigen content of inactivated oil newcastle disease vaccines by a new laboratory method

الملخص EN

A total of 54 E.

coli isolates, previously isolated from cases of clinical and subclinical mastitis in buffaloes, were tested for their virulence factors.

The majority of isolates were positive the mannose-sensitive haemagglutination (MSHA) type and were able to survive and grow in serum.

Only 2 out of 54 E.

coli strains, belonging to O114 and O86, were enterotoxigenic, while 3 strains belonging to O126 and O86 were able to produce Vero-toxin and one strain belonging to O86 was invasive and caused keratoconjunctivitis in rabbit model used.

LD50 of different LPS extracted from different E.

coli serogroups varied from 190 to 260 µg.

There were no clear differences among the different E.

coli serogroups.