Equine Health Update EHU Vol 20 Issue 02 - Page 50

EQUINE | African Horse Sickness once they reached the clinical end-point and a post- mortem was performed. Virus in myocardial tissue was confirmed as African horse sickness virus types 3,5,9 by type specific real time qPCR. Results All horses developed clinical signs of AHS, and signs included hypothermia; tachycardia; tachypnoea; supraorbital fossa oedema; and petechial haemorrhages. Infected horses showed severely impaired left ventricular systolic function characterised by myocardial dyskinesis; decreased ejection fraction and fractional shortening. cTnI was elevated in all cases, suggesting myocardial injury. Post mortem changes were consistent with the mixed form of AHS in all cases, and included pulmonary oedema, subcutaneous and intramuscular oedema, hydrothorax, hydropericardium, myocardial haemorrhages and ascites. Conclusions and significance We concluded that AHS is associated with severely impaired left ventricular function secondary to myocardial injury. This implies an alternative (or additional) cardiogenic mechanism for the pulmonary (and interstitial) oedema seen in clinical cases and provides a framework for therapeutic intervention using cardiac specific drugs. Diuretics, angiotensin- converting enzyme (ACE) inhibitors and positive ionotropic drugs are the mainstay of treatment for cardiac diseases resulting in heart failure, and are the logical choice for horses with AHS demonstrating myocardial dysfunction and clinical evidence of heart failure. Diuretics are used to reduce water and sodium retention by the kidneys, thereby reducing intravascular volume, ventricular filling pressures (preload) and wall stress. Furosemide is a loop diuretic that prevents reabsorption of sodium and chloride from the thick ascending loop of Henle, and is considered to the most widely used diuretic in the treatment of heart failure. 50 The pharmacokinetics and dosing of furosemide has been extensively studied in the horse, and it has been demons ]Y][[][\Hو x$ [Yš\YXY[[XH]\\\ NH \[ZX]Z[X[]Hق\[ZYH[YZ[\\Yܘ[H\܈]\[[\]Z][[Hو HY\[XB]\\\[ܜ\  \[ZYH\Y[\Y܈X[HYX\B]\[\X[[]\YXHX][[ۘ\BY[XH[ܜ\]R]\XXH[X[X\ˈ]\ۙY\Hو\[ZYH[\H\\]]ۘZ][\HوPH[X]ܜš\[\X]K\[YHXܙX\\™[HHو\[ZYKH[[$[[[[$[\ۙH\[H PTH\X]]Y[[\XH][\Hو\[ZYHH[ܙX\[[YH[[H^Hو\[ZYH\][PH[X]ܜܚH][[H۝\[ۈق[[[[H[[[[RK\XHYX[BX]]HوHPTˈ[Y][ۋPH[X]ܜ\\\[\\\[H[[ܙX\H[\\X]BH][X][H[\ۜX܈YXق[[[[RK\YX\Y\YHXܙX\[œ\[ZX\[\\\[K\[ܙX\[ܝ\H[YKPH[XZۈYZ[[B\[]܈X[K\YܙKPH[X]ܜH[HXZۂوYZ[[[ܙX\HYZ[[][X[۝X]HH\[]܈X[ۈوPH[X]ܜ˂H[Y]وPH[X]ܜ܈HX]Y[وX\Z[\H]HY[[\X\Y[[X[[ŒK ]\\H\]H[ܛX][ۈ[ܜ\ˈB\XX[]XوPH[X]ܜ]H[\ۙB[[Z[\H[\Y][ۋ[]\Y[[]\[ZX[]Z[X[]HY\ܘ[YZ[\][ۈ\œ܋[H\\]]H\XX[[ZXYK\š\Y[\X\Y][^\[\[YX]B][X][\[HPH[X][ۈ []HHق(\]Z[HX[\]H8(