A new study published in the U.S. Centers for Disease Control and Prevention’s Emerging Infectious Diseases links a new strain of methicillin-resistant Staphylococcus aureus(MRSA), once found only in pigs, to more than 20 percent of all human MRSA infections in the Netherlands.

The new strain of MRSA, NT-MRSA, emerged in the Netherlands in 2003 and increased steadily until by 2006 it accounted for more than one out of every five human MRSA infections, many of them in either pig farmers or cattle farmers. The NT-MRSA cases clustered in regions of the country with high densities of pig and cattle farms. The new strain has high rates of hospitalization, suggesting that it causes severe disease.

U.S. still has no system to monitor MRSA in animal production; Congress needs to compel government action.