TABLE 1:

Experimental set-up (vaccination – challenge)

Study (dogs per group)	Treatment group	Antiserum admin. (48 hrs before 1st vacc.)	Vaccines and route	First vaccination		Second vaccination		Serogroup used for Leptospira challenge‡
				Age (weeks)	Volume (ml)	Age (weeks)	Volume (ml)
1 (8)	L4	–	L4*+DHPPi* sc KC† intranasal	6	1 0.4	10	1 –	Canicola
	Control	–	DHPPi sc KC intranasal	6	1 0.4	10	1 –
2 (8)	L4	–	L4+DHPPi sc KC intranasal	6	1 0.4	10	1 –	Icteroh.
	Control	–	DHPPi sc KC intranasal	6	1 0.4	10	1 –
3 (8)	L4	–	L4+DHPPi sc KC intranasal	6	1 0.4	10	1 –	Gripp.
	Control	–	DHPPi sc KC intranasal	6	1 0.4	10	1 –
4 (8)	L4	–	L4+DHPPi sc KC intranasal	6	1 0.4	10	1 –	Australis
	Control	–	DHPPi sc KC intranasal	6	1 0.4	10	1 –
5 (8)	L4	YES	L4 sc	6	1	10	1	Canicola
	Control	YES	–	–	–	–	–
6 (8)	L4	YES	L4 sc	6	1	10	1	Icteroh.
	Control	YES	–	–	–	–	–
7 (8)	L4	YES	L4 sc	6	1	10	1	Gripp.
	Control	YES	–	–	–	–	–
8 (8)	L4	YES	L4 sc	6	1	10	1	Australis
	Control	YES	–	–	–	–	–

*In studies 1–4, in the groups designated ‘L4’ tetravalent leptospirosis vaccine mixed with DHPPi (live attenuated canine distemper virus, canine adenovirus type 2, canine parvovirus and canine parainfluenza virus) vaccine was used

†KC vaccine (live attenuated canine parainfluenza virus and Bordetella bronchiseptica) was only administered at six weeks of age

‡Bacterial cell concentrations (cells/ml) were (per study no.): no. 1, 1.0×10⁹; no. 2, 1.0×10⁹; no. 3, 1.0×10⁹; no. 4, 9.5×10⁹; no. 5, 5.0×10⁸; no. 6, 1.0×10⁹; no. 7, 2.0×10⁹; no. 8, 1.0×10¹⁰. Challenge was done three weeks after the second vaccination