The Difference Between HPAI and LPAI H5N1

"Low Path Avian Influenza" like LPAI H5N1 can be found in birds all around the world.  It is not a merciless killer of its bird hosts.

"Path" refers to pathogenic and reflects the fact that it is not a killer. H5 is an intestinal virus in birds. In North America many birds have tested LP H5N1 positive. As long as it does not mutate to High Path (HPAI) we need not fear it.

High Path H5N1 (a merciless killer) originated in Southeastern China where peasants live in close proximity to ducks and chickens and pigs and are exposed to fecal contamination of their living and sleeping spaces and  even their food. An intestinal (epithalial tissue) virus in birds can become a nose and throat and lungs (all epithalial tissue) virus in pigs and humans and other animals like cats and dogs. High Path kills all of its human hosts with about 60 percent or greater efficiency. You want to avoid it as much as possible.

Low Path Bird Flu strains can mutate into High Path strains at any time. Just like Low Path H5N1 mutated into High Path H5N1 in China and then spread to the rest Asia, Europe and Africa, we have seen H7N2 mutate from low path into a high path virus in the Eastern United States.  In 2002  in Virginia there was an  H7N2 Outbreak among poultry in the Shenandoah Valley, with 1 person found to have seriologic evidence of infection. Again in New York State in 2003 there was one person hospitalized.

Again in 2003 in the Netherlands there were H7N7 Outbreaks in poultry on several farms, followed by infections among pigs and humans. A total of 89 people were confirmed to have infection; most were poultry workers. One death occurred, a veterinarian who visited one of the affected farms. Most cases resulted from direct contact with infected
poultry; 3 cases possibly were person-to-person transmission.