Transmission of A(H1N1)2009 Virus from Human to Birds Confirmed

August 31, 2009 — 

On August 23, the Institute of Public Health (Chile) communicated to ProMED-mail the 1st isolation of an [influenza] A(H1N1) swine virus in turkeys.

The finding was reported by the Chilean farming agency SAG and the confirmation and genetic studies are being conducted at the Instituto de Salud FAblica de Chile (national reference laboratory).

The genetic and antigenic characteristics of the hemmaglutinin (HA) gene of the turkey's virus in this outbreak showed 99.5 to 98.9 percent similarity to the [Influenza]A/California/4/2009 reference strain and 100 percent similarity with the strains circulating in Chile.

The lab is now reporting results of the neuraminidase genetic sequencing studies. In this gene the turkey strain was shown to be 99.7 percent similar to the pandemic strains circulating in Chile in human cases, and to have 99.5 percent similarity to the reference strain A/California/4/2009, 80.5 percent to 86.5 percent similarity to avian influenza A virus strains (H1N1, H5N1, H6N1, H7N1) and 83.6 to 92 percent similarity to swine influenza virus strains (H1N1) isolated in different countries during years 2000 to 2009.

The conclusion of the genetic sequencing studies is that the influenza virus (H1N1) isolated from turkey corresponds to a variant of the influenza A(H1N1)2009 virus that has been circulating in Chilean people. -- Source: ProMED-mail, August 29, 2009 By: Julio Garcia Moreno MD, MSc Head, Biomedical Department Instituto de Salud FAblica de Chile