Comparison of virulence for guinea pigs and mice of different Coxiella burnetii phase I strains
Kazár, J.; Lesý, M.; Propper, P.; Valková, D.; Brezina, R.
Acta Virologica 37(6): 437-448
1993
ISSN/ISBN: 0001-723X PMID: 8010182 Document Number: 413265
Virulence of 4 C. burnetii phase I strains associated with acute (Nine Mile and Luga strains) and chronic (S and Priscilla strains) forms of Q fever, respectively, for outbred guineapigs and inbred BALB/c mice was compared. In guineapigs exposed to infectious aerosol, virulence of the strains Nine Mile, Luga and S was similar, because they all caused lethal infection and high febrile reaction (FR). By contrast, exposure to similar doses of the strain Priscilla resulted in the non-lethal infection manifested only by low, dispersed and protracted FR during a 20-day-period of observation. Lower virulence of the strain Priscilla than of the strains Nine Mile and S was observed also in guineapigs infected intraperitoneally (ip). In mice, a comparable degree of multiplication in the spleen on day 6 ip infection was observed with the strains Nine Mile, Luga and S, but not with the strain Priscilla, when lower infectious doses were used. Whereas the highest doses (107 EID50) of the strains Nine Mile and S were lethal for mice during the 2nd week post infection (p.i.), the strains Luga and Priscilla did not kill mice with 10-times lower (106 EID50) doses. At the same time, agglutination antibody response detected 4 weeks p.i. was very similar in guineapigs with all strains under study and in mice it did not differ markedly, reflecting the infectious dose used.