23 Nov 2009 Fatal H1N1 Cluster in Texas Raises Pandemic Concerns

[Watchman]

Fatal H1N1 Cluster in Texas Raises Pandemic Concerns
Recombinomics Commentary 22:55
November 23, 2009

A hospital spokesman has confirmed the second recorded H1N1 related death in Nacogdoches County. The 53-year-old oil rig worker from Enid, Oklahoma died Friday at 3:50 p.m.

The victim checked into Nacogdoches Memorial Hospital last week when he began experiencing severe symptoms.

This update follows the death of his roommate, a 55-year-old oil rig worker from Mississippi, who passed away Thursday morning as a result of H1N1.

The above comments describe the deaths of roommates infected with H1N1. Since the vast majority of H1N1 infections are mild, the death of two roommates within 24 hours of each others raises concerns that they were infected with a lethal contagious form of the virus. Recent reports out of Ukraine has raised concerns that H1N1 with the receptor binding domain change D225G, is such a virus.

Ukraine has reported 388 pneumonia deaths in the past several weeks and agency reports described 90 cases which involved total destruction of both lungs. Recently released sequences from Mill Hill in London included 4 fatal cases and all four cases had D225G, which was not present in the other six sequences which appear to be from milder cases.

D225G was identified during the 1918 pandemic in lung samples from victims in New York in 1918 and London in 1919. This change was also detected during 2009 pandemic target reassortants, indicating D225G is present as mixtures in various individuals. These mixtures can segregate during passage through hosts since D225G is a receptor binding domain that influences tissue tropism and allows the virus to target alpha 2,3 receptors, such as those seen in type II lung alveolar cells. Many of the fatal cases in the United States have also involved ARDS and hemorrhagic lungs, raising concerns that isolates with high levels of D225G can produce the increasing levels of such fatalities being reported throughout the northern hemisphere, including cases in Norway.

Since the D225G can circulate as a mixture, transmission and lung targeting can be facilitated by pseudo-typing. Moreover, D225G was identified in the vaccine target, A/California/7/2009, indicating claims of "spontaneous mutations" in patients in Norway or Ukraine are false.

The increasing number of deaths, including the cluster described in Texas raises concerns that D225G is gaining traction. More sequencing of samples near lung tissues in severe and fatal cases would be useful.