A replication analysis of foot-and-mouth disease virus in swine lymphoid tissue might indicate a putative carrier stage in pigs

Table 1 Specific infectivity of FMDV RNA of different lymphoid tissues

	Tonsil	Spleen	Thymus	ING	RTF	MED	MES	PRE
1	ND^a (+++)^b	ND (+)	ND (-)	ND (-)	ND (-)	ND (-)	ND (-)	5 × 10^-7
	6 × 10^{-4 c}	ND (+)	ND (+)	ND (-)	ND (+)	ND (-)	ND (-)	7 × 10^-8
2	ND (+)	2 × 10^-4	7 × 10^-5	1 × 10^-4	ND (+)	ND (+)	1 × 10^-5	5 × 10^-6
	2 × 10^-7	2 × 10^-5	4 × 10^-6	1 × 10^-6	ND (+)	ND (+++)	ND (+++)	2 × 10^-6
3	2 × 10^-4	ND (+++)	2 × 10^-5	ND (++)	1 × 10^-7	4 × 10^-4	ND (+++)	ND (+)
	5 × 10^-4	ND (+++)	ND (++)	ND (+)	ND (++)	ND (+++)	ND (+++)	ND (-)
	3 × 10^-7	ND (+++)	ND (++)	ND (++)	ND (+)	ND (+++)	ND (+++)	ND (+)
7	2 × 10^-7	ND (+++)	ND (+++)	ND (+++)	ND (++)	ND (+++)	ND (+++)	ND (+)
	ND (++)	ND (+++)	ND (+++)	ND (+++)	ND (++)	ND (+++)	ND (+++)	ND (+++)
14	7 × 10^-6	ND (+++)	ND (+++)	ND (+++)	ND (+++)	ND (+++)	ND (+++)	ND (+++)
	1 × 10^-5	ND (+++)	ND (++)	ND (++)	ND (+++)	ND (+++)	ND (+++)	ND (+++)
17	ND (+++)	ND (+++)	ND (+++)	ND (+++)	ND (+)	ND (+++)	ND (+++)	ND (+)

It is indicated the specific infectivity of FMDV RNA at different times post-inoculation (right columna) from tonsil, spleen, thymus and several lymph nodes [inguinal (ING), retropharyngeal (RTF), mediastinal (MED), mesenteric (MES), and prescapular (PRES)].
^a ND: not determined.
^b Cythopatic effect: BHK-21 cells were infected with homogenate from tissues and cytophatic effect (cpe) was evaluated at 48 h post-infection. (-), no cpe; (+), 10-20% of cpe; (++) 50% of cpe; (+++) 100% cpe.
^c Specific infectivity is expressed as the number of PFU per viral RNA molecule.

ISSN: 1297-9716