Illustration of a world map showing a truck going from the US to Mexico, a plane going from Europe to Mexico, and a pig surrounded by various viruses in Mexico
Infographic: How H1N1 Came to Spark a Pandemic in 2009
The pathogen known as swine flu evolved in pigs in Mexico following imports of the livestock from the US and Europe.
ABOVE: © istock.com, Samuil_Levich; © istock.com, bgblue; © istock.com, ankomando
Infographic: How H1N1 Came to Spark a Pandemic in 2009
Infographic: How H1N1 Came to Spark a Pandemic in 2009

The pathogen known as swine flu evolved in pigs in Mexico following imports of the livestock from the US and Europe.

The pathogen known as swine flu evolved in pigs in Mexico following imports of the livestock from the US and Europe.

ABOVE: © istock.com, Samuil_Levich; © istock.com, bgblue; © istock.com, ankomando

swine flu

A grid of images showing different cross sections of a human brain MRI.
Study Links Flu to Increased Parkinson’s Risk a Decade Later
Dan Robitzski | Nov 19, 2021
Epidemiological research suggests that a flu diagnosis might be one factor in the eventual onset of the neurodegenerative disease, but experts say it doesn’t prove a causal relationship.
a veterinarian in a white hazmat suit holding a small pig
The Long Journey to Resolve the Origins of a Previous Pandemic
Martha Nelson | Sep 2, 2021
Dozens of researchers, including myself, worked for years to uncover that swine flu had leapt to humans from a pig in Mexico in 2009. We learned a lot about influenza evolution, pig farming, and outbreak risk along the way.
Swine Flu Strain Has Pandemic Potential: Study
Jef Akst | Jun 30, 2020
An influenza virus identified in pigs in China has a concerning mix of genes, but experts say there is no way to know if it will evolve to be transmissible between humans.
On the Flu Vax–Narcolepsy Link
Anna Azvolinsky | Jul 1, 2015
Researchers identify a peptide present in the swine-flu vaccine linked to narcolepsy that may be responsible for the sleep disorder.
Not Swine Flu
Abby Olena | Feb 17, 2014
The strain of influenza that caused the 1918 pandemic probably came from birds, a study shows.
Watch the Pigs
Edyta Zielinska | Jun 25, 2012
Sampling for potentially pandemic strains of influenza virus at hog farms is lax compared with poultry farms, worrying some experts.