The nation's first cases of H1N1 resistant to Tamiflu came from a Henderson County camp, health officials said Friday.
Two campers from Camp Blue Star in Henderson County are resistant to Tamiflu, an antiviral drug used to treat the swine flu.
One camper resides in Buncombe County, and the other lives in Florida.
The campers became ill with H1N1 in July while receiving Tamiflu for exposure to other ill campers. Both had mild illness and have since recovered.
"Both are fine," said Tom Bridges, health director for the Henderson County Health Department.
The two cases were discovered by the federal Centers for Disease Control through testing of samples submitted by the Henderson County Health Department through the N.C. State Laboratory of Public Health. Camp Blue Star has completed all summer camp sessions and now is closed for the season.
The above comments describe two more Tamiflu resistant cases in the United States. Like the first two reported cases, these two cases represent a cluster, strong suggesting the presence of resistant H1N1 as a minor population, which is discovered during or after Tamiflu treatment. Like most of the prior cases these two campers developed resistance while on prophylactic Tamiflu. Although the day of treatment isn't given, the development of resistance in two campers (see map) suggests both were infected with H1N1 that contained H274Y
Thus, in one sense these campers are similar to other prophylactic patients, but the clustering is like the immune-suppressed patients inSeattle, who developed resistance while being treated. The resistance in two patients from the same area raised concerns that the H1N1 was a mixture and resistance was in genetically similar viruses. Thosesequences were released yesterday by the CDC and both sequences gave mixed signals and shared a polymorphism in addition to H274Y.
The results in North Carolina on samples collected in July raise concerns that these campers seeded additional regions when they left camp. There have been outbreaks in schools in the south, in North Carolina and adjacent states (see map), and at least one school has recommended prophylactic Relenza for roommates of confirmed college cases, further suggesting that Tamiflu resistance is being detected, but not reported.
Since the campers were infected in July, it is unclear if these cases were among those mentioned by the WHO. Additional cases were acknowledged, but the number and locations were withheld.
These two cases strongly suggest that Tamiflu resistance is widespread and linked to the recent explosion of clusters in schools in the area.
Release of these sequences, as well as more aggressive sequencing of isolates from cases in the area would be useful.