TABLE 2.

Viremia in inoculated ducklings^a

Virus	No. of ducklings developing high-titer viremia/total no. of ducklings	No. of ducklings with transient viremia/total no. of ducklings	No. of ducklings with persistent viremia/total no. of ducklings
DHBV (6 × 107)	6/6	NTb	4/4
DHBV (1.5 × 107)c	5/6	NT	NT
MDHBVa	5/5	2/5	3/5
MDHBVbd	3/6	NT	NT
CWHBV	5/5	NT	4/4
PTHBV	4/6	1/6	3/6
OSHBV	2/4	0/4	2/4
ASHBV	0/6

^aThree-day-old ducklings were inoculated intraperitoneally with 100 μl of virus stock containing 6 × 10⁷ (for DHBV, MDHBVa, MDHBVb, CWHBV, and PTHBV) or 1.5 × 10⁷ (for DHBV, OSHBV; and ASHBV) genome equivalents of virus particles, as described in Materials and Methods, and bled weekly, beginning at 6 days postinfection. Viremia was detected by a hybridization spot test (42). High-titer viremia represents >2 × 10⁷ virus particles per ml of duck serum. Ducks that remained viremic at the end of the experiment, at 6 to 10 weeks postinfection, were scored as persistently infected. Viremia was not detected in ducks inoculated with ASHBV during this same interval.

^bNT, not tested.

^cDucklings in this group were euthanized 1 week postinfection.

^dDucklings in this group were euthanized at 5 week postinfection.