Colorado became a case positive state on July 23, 1998, with the isolation of VSV, Indiana strain, from a horse on a premises located in Boulder County. Nine additional investigations were reported, six of which were positive for VSV. There were two positive premises in Boulder County and four positive premises in Weld County. One of the positive premises in Weld County was also positive for virus isolation. Two investigations are pending, and one is negative. There are a total of seven positive VSV premises in Colorado.

No new VSV investigations were reported in Arizona, where the total number of positive premises remains at fifteen.

Two new VSV investigations were reported in New Mexico, one of which was positive for VSV. The new positive premises is located in Sandoval County. The other investigation is still pending. The new positive premises brings the total in New Mexico to nine.

No new investigations were reported in Texas, where the number of positive premises remains at one