Porcine epidemic diarrhea (PED) virus was introduced into the United States in 2013. Which factor most likely contributed to its introduction?

• A. Globalization (travel and trade of humans and animals)
• B. Climate change
• C. Biosecurity lapses in farms
• D. Local wildlife reservoirs

Answer: (A)

Global movement of animals and animal products often brings pathogens into new regions. PEDV’s entry into the United States around 2013 is best explained by globalization—international trade and travel involving pigs and pig-derived inputs (like feed ingredients) that can carry infectious material across borders. Once such a pathogen crosses into a new country, close contact between animals and lapses in farm biosecurity can amplify spread, but the initial introduction is most directly tied to cross-border trade and movement. Climate change and local wildlife reservoirs can influence later dynamics, but they don’t directly explain how the virus first arrived.