Later, we took up the issue (discussed earlier) of detection by RT-PCR of inactivated virus. Although our work yielded only a partial solution , the study has been taken up by others and progress will surely be made. We were able to characterize some of the changes in the virion that occurred with inactivation, in the hope that this information may point to further modes of attack (Nuanualsuwan and Cliver 2003a, b) .