Sampling was carried out at 5 different stages, 20, 28, 33, 42 and 1-2 weeks post tail resorption, according to the schedule in Table 1 . Tadpoles were sampled at each of the 5 stages for the detection of virus by real time PCR, and at all stages except stage 20, where tadpoles are very small, for the analysis of native adult globin profiles. However, tadpoles were only sampled up to and including stage 33 (just before the onset of native adult globin production) for the detection of viral adult globin. Five tadpoles per group were sampled at all stages except post tail resorption, where, for statistical purposes, 30 animals per group were sampled.