Serum amyloid A concentration in foals – Can it help when making a treatment decision in foals with pneumonia?

Serum amyloid A concentration in foals – Can it help when making a treatment decision in foals with pneumonia?

Serum Amyloid A Konzentration in Fohlen: eine Hilfe für die Therapieentscheidung bei Fohlen mit Pneumonie?

Thomé R, Weber C, Rohn K, Venner M

DOI: 10.21836/PEM20180111
Year: 2018
Volume: 34
Issue: 1
Pages: 61-67

Bronchopneumonia is a frequent and serious pulmonary disorder in foals on equine breeding farms and the most common pathogens responsible for this condition are Streptococcus equi ssp. zooepidemicus (Strep. eq. ssp. zoo.) and Rhodococcus equi (R. equi). As foal pneumonia occurs endemically on many studs worldwide, practitioners are asked to evaluate regularly all foals in order to detect early affected foals and reduce the losses. Some of those will show neither clinical symptoms nor hematological changes but obvious pulmonary lesions at sonography. Consequently the question of treating these foals will rise. The aim of the study was to evaluate the serum amyloid A (SAA) concentration in clinically healthy or mildly sick foals showing either no findings, moderate or severe findings at lung sonography. The investigation was a prospective study. A total of 33 foals were examined once weekly starting at the age of two weeks over a period of four months. Clinical signs, body temperature, ultrasonographical pulmonary findings and haematological findings including WBC count and SAA serum concentrations were monitored. After each sonographical examination of the lung, the diameters of pulmonary consolidations were added to obtain an abscess score that represents the severity of pulmonary disease of these foals. The frozen serum samples of the 33 foals were analysed at different stages of pneumonia. Altogether, 49 samples of healthy state (abscess score=0cm), 31 of moderately sick state (abscess score=1–9cm, no indication for treatment) and 22 of severe pulmonary damage (abscess score >10cm, indication for treatment) were analysed by enzyme-linked immunosorbent assay to determine the SAA concentration. The median SAA was 18µg/ml (25th percentile: 1.5µ/ml; 75th percentile: 52.7µg/ml) in the healthy foals, 5.6µg/ml (25th: 2.4µg/ml; 75th: 82.3µg/ml) in the moderately sick foals and 80.2µg/ml (25th: 79.3µg/ml; 75th: 160µg/ml) in the foals requiring treatment. These results show that the SAA concentration might be considered as an efficient parameter for making a treatment decision in foals in the early course of pneumonia.