Temperature has a greater effect than salinity on microbial survival in saltwater from a single equine hydrotherapy unit.

OBJECTIVE: To determine the ability of bacteria commonly isolated from equine limb wounds to survive in saltwater obtained from an equine hydrotherapy unit at different salinity concentrations and temperatures. METHODS: Saltwater samples were obtained over a 2-week period (January 22, 2024 to February 2, 2024) from an equine hydrotherapy unit used for clinical patients, kept at either full salinity per manufacturer recommendations or diluted to half salinity to mimic the dilution that likely occurs in the clinical setting between cases when holding tanks are replenished with tap water only. Samples were then autoclaved to eliminate preexisting bacterial contamination before individual inoculation with Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus zooepidemicus. Each inoculated sample was maintained at 2, 22, or 44 °C to represent typical holding tank conditions. The bacterial concentration was determined at each condition every 24 hours up to and including 96 hours. The lower limit of detection was set at 1 CFU/mL. RESULTS: Salinity did not affect bacterial survival. Bacterial concentrations generally decreased with increasing temperature over time. Escherichia coli, S aureus, and S zooepidemicus concentrations decreased to the lower limit of detection at 44 °C by 24 to 48 hours, while P aeruginosa concentrations significantly decreased over 24 hours but remained well above the lower limit of detection. CONCLUSIONS: Common bacterial isolates of equine limb wounds can survive in typical saltwater hydrotherapy conditions. CLINICAL RELEVANCE: Further investigation is warranted to determine the clinical relevance of these findings including protocols for hydrotherapy unit disinfection, wastage of treatment water, and case inclusion/exclusion criteria.

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.