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Use of apparatus for controlled infection of buffalo calves with an aerosol of Pasteurella multocida

1969; Elsevier BV; Volume: 79; Issue: 2 Linguagem: Inglês

10.1016/0021-9975(69)90005-x

1532-3129

Gillian H. Prince,

Indoor Air Quality and Microbial Exposure

an apparatus suitable for infection of both buffalo calves and adults with aerosolised material is described. An enclosed system was used with a continuous aerosol generation of about 48 ft.3/minute with output fans adjusted to create a slight negative internal pressure. Animals wore a mask fitted over the nose and apparently breathed normally. The number of viable P. multocida reaching the mask, as determined by sampling with Porton liquid impingers, was affected by the relative humidity of the atmosphere. Two calves infected with a low dose developed marked symptoms; one died within 69 hours but the other recovered. Increasing the dose 10 fold or more caused death of 4 non-immune calves within 27 to 33 hours. Post-mortem findings were similar to those of natural cases. Three calves vaccinated with saline suspensions of bacteria of different antigenic composition and challenged on the same day survived for 3 to 5 days compared to 29 hours for the control.