Tissue distribution of ENTV-1 provirus in sheep experimentally infected with ENA inoculum. PCR (A) and hemi-nested PCR (B and C) amplification of exogenous ENTV-1 proviral DNA from genomic DNA extracted from various tissues of sheep experimentally infected with ENA inoculum. Distribution of ENTV-1 provirus in an experimentally infected sheep that developed a nasal tumor (A and B) and in a sheep that did not (C). Genomic DNA isolated from healthy sheep lung (−) and naturally acquired ENA (+) were used as a negative and positive controls, respectively. M indicates molecular weight marker.