Equine Health Update EHU Vol 20 Issue 03 - Page 35

CPD Article | EQUINE The cranioventral right cranial and middle lung lobes are more severely affected 11 supporting aspiration or inhalation of organisms rather than a hematogenous spread of infectious organisms 11 . The right hemithorax is more often affected, probably due to the direct route of the mainstem bronchus 11 . Polymicrobial infections are common with gram positive and negative organisms and anaerobic and aerobic populations present 9 . Commonly isolated bacteria include: Pasteurella, Streptococcus, Actinobacillus, Staphylococcus, Klebsiella, E. coli, Bacteroides and Clostridium 7 . Many of these bacteria are normally found within the oropharyngeal region 11 with the most commonly isolated bacteria being Streptococcus zooepidemicus 13 . Clinical signs Clinical signs are dependent on the severity and duration of the disease 11 . Clinical signs can take up to 5 days to develop 6 after long distance travel and daily rectal temperature monitoring, post travel, will allow early identification of a sick horse 7 . Common acute clinical signs include 10 11 : move or a recumbent patient can be presented 3 10 . These cases should be carefully differentiated from those with rhabdomyolysis, laminitis and colic 6 . Disease of greater than 2 weeks is regarded as chronic and additional clinical signs noted include 11 : Intermittent pyrexia Rapid weight loss Oedema – sternal and limb As most of these clinical signs could be associated with any infectious respiratory condition induced by travel stress, it would be prudent to isolate affected animals and implement strict biosecurity measures 18 until a definitive diagnosis can be made 14 . Infectious and contagious diseases to consider are: • Equine herpes virus (EHV), • Equine Influenza (EI) and • Strangles (Streptococcus equi subspecies equi) 14 . Based on clinical signs alone, other non- infectious differential diagnoses to consider and additional diagnostic tests are 10 : Pyrexia Soft moist cough Nasal discharge: variable - mild to severe; often mucopurlulent to serosanguineous13 Anorexia Depression and lethargy Respiratory changes: tachypnea, shallow breathing, flared nostrils Tachycardia Toxic mucous membranes • Neoplasia – cytological evaluation of trans tracheal aspirate (TTA) or thoracocentesis sample, chest radiographs and ultrasonography; • Congestive heart failure – jugular distention, cardiac auscultation for evidence of murmurs and arrhythmias, ECG/echocardiography; • Diaphragmatic hernia - history of trauma, chest radiographs and ultrasonography. Diagnostic tests Due to pleural pain, a stiff stilted gait, reluctance to As a nasal discharge and cough are rather non- specific clinical signs, careful chest auscultation is • Volume 20 Issue 3 | October 2018 • 35