Method for studying particle size and infective potential of infectious bovine rhinotracheitis virus aerosols

A technique is described for estimating the number of potential respiratory infectious loci of aerosolized infectious bovine rhinotracheitis virus.

Some studies of infectious bovine rhinotracheitis (IBR) virus infection in calves

Six dairy calves, six and one-half to nine months old, were exposed to a strain of infectious bovine rhinotracheitis (IBR) virus of bovine fetal origin by one of the various routes - nasal, vaginal, preputial or contact. Neither after initial exposure nor following challenge of their immunity did any of these animals manifest the IBR respiratory syndrome, although two of them (inoculated per vagina/prepuce) developed pustular vulvovaginitis or balanoposthitis. Also, one five-day old dairy calf which had received colostrum and milk of its IBR-immune dam, was inoculated intranasally with the same strain of IBR virus. This animal exhibited severe signs of IBR. The virus was recovered from all but three of the seven calves after initial exposure and from all but one animal following challenge of their immunity. Immune responses of these calves resembled those of adult cattle.

Experimental exposure of pigs to infectious bovine rhinotracheitis (IBR) virus

Thirteen specific-pathogen-free pigs were used in an experiment to determine the pathogenicity of IBR virus for pigs. Three pigs were used as controls, eight were exposed to IBR virus by either the intravenous, subcutaneous, intratracheal, or intranasal route, and two pigs served as contact controls. The clinical response consisted of a temperature rise, depression and variable lymphocytosis. The major tissue alterations were interstitial pneumonitis, and peribronchiolitis with round cell aggregates and giant cell formation. IBR virus was not recovered from any of the pigs. A serologic response was detected in only the pig injected intravenously.