Hurricanes, Industrial Hog Operations, and Acute Gastrointestinal Illness in North Carolina, USA

Abstract

Background and aim: North Carolina (NC) is the third most hurricane-prone state and second leading hog producer. NC’s hogs are housed in industrial hog operations (IHOs) in its eastern, hurricane-prone region. Hurricanes can inundate hog waste lagoons, transporting fecal bacteria that may cause diarrhea, vomiting, and/or nausea, collectively known as acute gastrointestinal illness (AGI). Hurricanes Matthew (2016) and Florence (2018) were NC's most recent deadliest hurricanes. We aim to understand the association between hurricanes and AGI in areas with and without IHOs. Methods: We used NC ZIP code-level surveillance data to calculate rates of AGI emergency department (ED) visits during 2016-2019. Using gridded PRISM precipitation data and swine permit data, we assessed the increase in AGI rate during the three weeks after Hurricanes Matthew and Florence in ZIP codes with heavy rain (>75th percentile of storm precipitation) and ≥10 IHOs and in ZIP codes with heavy rain but no IHOs by comparing AGI rates in these areas to their AGI rates during comparable non-hurricane time periods (2017, 2019). Results: The AGI rate in ZIP codes with heavy rain and ≥10 IHOs increased 13% (RR=1.13, 95% CI: 1.00, 1.29) after Hurricane Florence and 8% (RR=1.08, 95% CI: 0.87, 1.33) after Hurricane Matthew, while the AGI rates in ZIP codes with heavy rain and no IHOs experienced no increase (Florence: RR=0.99, 95% CI: 0.88, 1.12; Matthew: RR=0.98, 95% CI: 0.82, 1.16). ZIP codes with heavy precipitation and IHOs also had a higher proportion of Black, American Indian, and Hispanic residents than the state average. Conclusions: Heavy rain from hurricanes in areas with IHOs may increase AGI rates, disproportionately harming people of color in NC. Keywords: Climate change, extreme weather, hurricane, disaster, flooding, industrial animal operations