Quantitative assessment of human MRSA risks from swine

Area of Science:

• Public Health
• Infectious Diseases
• Microbiology

Background:

• Concerns exist regarding methicillin-resistant Staphylococcus aureus (MRSA) transmission from pigs to humans.
• Swine-associated MRSA (ST398) has been detected in various points of the transmission chain, from pigs to humans.
• Quantitative risk assessments for human health impacts are often lacking.

Purpose of the Study:

• To estimate the probability of human health harm from ST398-MRSA originating from pigs.
• To provide a conservative (upper bound) risk assessment for MRSA infections and fatalities in humans.
• To integrate available data for a quantitative evaluation of swine-to-human MRSA transmission risks.

Main Methods:

• Integrated available data from multiple sources.
• Constructed a probabilistic model to estimate risk.
• Calculated plausible upper bounds for human infections and fatalities.

Main Results:

• Estimated an upper bound of approximately one excess human infection per year among U.S. pig farm workers.
• Estimated an upper bound of one human infection per 31 years for the general U.S. population.
• Results are based on conservative assumptions and may be reduced with further data.

Conclusions:

• The quantitative risk of human health harm from swine-associated MRSA (ST398) is estimated to be low.
• Further data collection could refine these risk estimates.
• The study provides a framework for assessing risks associated with zoonotic pathogen transmission.