id	keyword
ajpf-639	swine
ajpf-639	h1n1
ajpf-639	viruses
ajpf-639	influenza
ajpf-639	humans
ajpf-639	origin
ajpf-639	gene
ajpf-639	h1n1 viruses
ajpf-639	north
ajpf-639	pandemic
ajpf-639	influenza viruses
ajpf-639	h1n1 influenza
ajpf-639	avian