Investigation of the Use of Serum Amyloid A to Monitor the Health of Recently Imported Horses to the USA

The objective of this study was to investigate the use of serum amyloid A (SAA) as an early indicator of subclinical inflammation in recently imported horses. Archived serum samples from 143 adult horses imported from Europe over 12 months were available for SAA testing. Based on clinical and hematological assessment performed shortly after arrival to a quarantine facility, the horses were characterized as healthy horses, horses with subclinical inflammation, and sick horses with and without hematological abnormalities. The majority of the horses (n = 109) were deemed healthy, 30 horses had evidence of subclinical inflammation based on hematological abnormalities, and 4 horses were sick. SAA values ranged from 0 to 3,000 µg/mL (median 9 µg/mL) in healthy horses and from 0 to 1,522 µg/mL (median 9 µg/mL) in horses with subclinical inflammation, while 3 out of 4 sick horses had elevated SAA values (range 15–1,923 µg/mL, median 590 µg/mL). The cause for the elevated SAA values in the majority of the healthy horses and horses with subclinical inflammation could not be determined. Overall, a single point in time SAA test did not add additional value to routine clinical and hematological monitoring in recently imported horses.