TABLE 3.

Aerosol inoculation of Legionella strains

Strain	Dose (total CFU)	No. of guinea pigs killed/no. tested	Comments	Retained dose
L. pneumophila serogroup 1 (Philadelphia)	1 × 109	2/3	Death within 5 days	∼2 × 105
L. longbeachae serogroup 1 ATCC 33462	1 × 109	0/3	No symptoms	2 × 105
L. longbeachae serogroup 2 ATCC 33484	1 × 109	0/3	No symptoms	∼2 × 105
L. longbeachae serogroup 1 A5H5	1 × 109	3/5	Death within 5 days (days 2 and 4)	3.5 × 105
B8	1 × 109	0/5	No symptoms	1 × 105
B8	1 × 1010	0/5	Slight symptoms in most animals	1.6 × 106