Particulate matter from wildfire smoke in northern Colorado appears to be associated with conjunctivitis in dogs.

OBJECTIVE: To evaluate ocular surface parameters in dogs with normal eyes when exposed to 3 different air quality index (AQI) categories corresponding to levels of normal air pollutants ("good," 0 to 50; "moderate," 51 to 100) and wildfire smoke ("smoke," 101 to 150). ANIMALS: 15 privately owned dogs. METHODS: A prospective cohort study with dogs living in northern Colorado. Ocular surface parameters (conjunctival chemosis and hyperemia, Schirmer tear test-1, tear film break-up time, fluorescein stain, conjunctival microbiology, etc) were evaluated when the AQI was reported in 1 of the 3 categories (good, moderate, and smoke) for 3 consecutive days. The AQI and air pollutant levels (particulate matter < 2.5 µm in diameter [PM2.5], ozone, etc) were retrieved from the AirNow database. RESULTS: Due to scheduling conflicts, only 7 dogs were examined during the smoke category. Average AQI in the 3 categories were good, 44.1; moderate, 73.7; and smoke, 103.7. The odds for more severe hyperemia and more severe chemosis for smoke were 5.39 and 7,853.02 times the odds, respectively, when compared to good AQI. Additionally, the odds for more severe chemosis were 34,656.62 times the odds for smoke when compared to moderate AQI. A significant relationship was found between chemosis and PM2.5. CONCLUSION: Exposure to increased AQI related to wildfire smoke caused a significant increase in conjunctivitis. The significant relationship between chemosis and PM2.5 could indicate that PM2.5 in wildfire smoke is associated with an inflammatory factor. CLINICAL RELEVANCE: Preventive measures (eg, use of eyewash, artificial tears, or eye protection) for dogs that are exposed to wildfire smoke should be instituted to decrease the risk of ocular irritation.

Increase in infected corneal ulcerations in dogs during the northern Colorado's 2020 wildfire season.

OBJECTIVE: In the fall of 2020, Colorado experienced the two largest wildfires in state history. The smoke blanketed the college town of Fort Collins, Colorado, the location of the Veterinary Teaching Hospital at Colorado State University (CSU-VTH). The objective for this cross-sectional observational study was to evaluate how these wildfires and the corresponding elevated air quality index (AQI)) was associated with infected corneal ulcerations in dogs when compared to the two previous years. ANIMALS: Seventeen dogs were included in this study. PROCEDURES: Medical records from dogs presented to the CSU-VTH ophthalmology service with infected corneal ulcerations in August, September, and October of 2020, 2019, and 2018 were evaluated. Only corneal ulcerations with growth on their microbial cultures were included in this study. RESULTS: The study revealed a significant increase in prevalence of infected corneal ulcerations in dogs presented to the CSU-VTH during the three wildfire months of 2020 that is, 3.5% (9/255) when compared with the two previous years, 2019: 1.0% (4/383, p = 0.04), and 2018: 0.9% (4/457) (p = .01). The AQI (mean ± standard error) was also significantly elevated for dogs that presented with infected corneal ulcerations in 2020 (70.2 ± 5.8) compared with 2019 (19.7 ± 8.7) and 2018 (45.6 ± 8.7) (p < .01). CONCLUSIONS AND CLINICAL RELEVANCE: Elevation of AQI from wildfires seems to be correlated with an increased prevalence of infected corneal ulceration in dogs. As the duration and frequency of wildfires continues to rise globally, the effects of these wildfires on animal health should be investigated further.