Declan Butler is reporting in tomorrow's Nature that the H5N1 strains currently circulating in Turkey carry mutations, "likely to make the virus better adapted to humans." According to Dr. Butler:
The Turkey outbreak is unusual, because of the large family clusters ofcases; the fact that many of those infected have only mild symptoms; and the speed with which infections have arisen — twenty cases, including four deaths, in less than two weeks. So scientists are urgently trying to establish whether the virus is behaving differently in this outbreak from previous ones in Asia. In particular, international teams are investigating the possibility that the virus is moving between people.
I speculated briefly last week about the odd behavior of the Turkey strain, and with 20 cases and 4 fatalities in two weeks, there may be reason for concern that the virus has changed its tropism to favor humans. One of the mutations, in the polymerase gene, is said to be among the ten that caused the 1918 pandemic strain to be so problematic. The other mutation is in the HA gene, which enables the virus to better target epithelial receptors in the nose and throat.
Dr. Butler reports that together these mutations may make it easier for the virus to be transmitted between humans. If this were a pandemic strain we would probably know it already. Unfortunately, human morbidity and mortality are likely the only clues we are going to have; as I've described previously, there is presently no scientific basis to predict the course of the flu. Alas, human institutions are complicating the process of gathering better data. Dr. Butler writes that:
Researchers are sequencing more strains from the Turkey cases, to see whether they share the mutations and to check for further changes. Samples were expected to arrive in London on 18 January, after being held up for more than a week in Turkey because of the Eid ul-Adha holiday period.
Given the threat, and the potential for rapid transmission beyond Turkey's borders, why didn't the WHO have a guy (or better yet, a dozen) on the ground chasing samples, with a private jet waiting to fly them to fully outfitted labs in western Europe? Or perhaps celebration of Eid prevented even the Turks from grasping how the situation was changing? In any event, I suspect we can ill afford to be without better intelligence from the field. The AP is just now reporting that Iraq is investigating a potential human death from H5N1, which occurred in a migratory flyway out of Turkey. One can only hope some of the $1.9B pledged today to fight the bird flu is spent on better surveillance.