Figure 4.

Cross-fostering from a low- to high-viral-load litter. The mean viral load (copies of Felis catus papillomavirus type 2 DNA per swab), with 95% confidence interval band, is shown for both the high-viral-load litter (darker shading) and low-viral-load litter (lighter shading). During the first week of life, one kitten was cross-fostered from the low-viral-load litter to the high-viral-load litter as indicated by the points. One skin swab was collected from this kitten prior to cross-fostering (white point) and two swabs were collected after the cross-fostering (black points). The cross-fostered kitten died at 2 weeks of age. Note that the viral load of this kitten increased markedly when moved to the high-viral-load litter. At around 6 weeks of age the kittens were weaned and moved to an outdoor run as indicated by the vertical line. This resulted in a loss of the difference in viral load between the two litters