Evaluating the Effects of Limestone Dust on Zoonotic Disease Transmission Between Pets and Humans

Abstract

Transmission of zoonotic diseases is driven by crosstalk among the environment, animal health, and human behavior. Industrial activities, such as limestone processing, produce airborne dust that can settle in homes, be taken up by pets, and potentially mediate pathogen transmission among households. The association between household zoonotic transmission and exposure to limestone dust has been supported by limited evidence. This study assessed the potential role of residential exposure to environmental limestone dust in zoonotic disease transmission between pets and human participants. We conducted a cross-sectional comparison study of 10 households exposed to limestone processing sites (n=5) and non-exposed households (n=5) with pets. Average (mean) ambient dust concentrations (in µg/m³) were obtained at the household level. Pet health measures included fur dust load (mg/cm²), respiratory signs, and zoonotic pathogen detection. Human subjects had respiratory symptoms and were diagnosed with zoonotic infections. The exposed and non-exposed groups were compared using descriptive statistics, independent-samples t-tests, and chi-square analyses. Mean ambient limestone dust levels were significantly elevated in exposed (205.0 ± 26.9 µg/m³) compared with non-exposed areas (52.0 ± 5.6 µg/m³; p < 0.001). Animals from exposed households had higher mean fur dust loads (3.7 vs 0.7 mg/cm²). They showed significant percentages of respiratory signs (80%) and zoonotic pathogen positivity (60%), as well as lower body weight compared with animals from non-exposed houses. Respiratory symptoms were recorded among human subjects: 80% in exposed versus 0% in non-exposed households, and a zoonotic infection was confirmed in up to 60% of those exposed. Although the status of exposure and zoonotic infection could not be linked statistically (Χ² = 1.90, p = 0.168), the trend related to exposure was the same across study periods. Quantitative findings revealed that high exposure of limestone dust was closely associated with a higher pet contamination and poor health status in pets and more respiratory signs and zoonosis-related diseases in humans, indicating the transporting role for these substances within a living environment exposed to dust.