Tenaciously surviving pleuropneumonia

Three-year-old thoroughbred racing filly Miss Tenacious was rushed to the Camden Equine Centre in 2014 with the life-threatening illness pleuropneumonia, commonly known as ‘travel sickness’ or ‘shipping fever’.

A very sick Miss Tenacious at the high of her illness weighing in at only 350kg compared to her normal 440kg

Depressed and not eating after arriving back in Sydney following a race in Melbourne, her owners took her straight to her veterinarian, who found she had a fever of 40.6oC, very injected and dark mucous membranes, and a significantly elevated heart rate. Suspecting pleuropneumonia, the veterinarian immediately referred her to Camden Equine Centre.

Pleuropneumonia is essentially a bacterial infection of the lungs involving the pleural space. This very debilitating disease commonly occurs when horses travel for long distances with their heads tied up.

Due to the elevated position of the horse’s head, bacteria from the oropharynx area have a greater opportunity to contaminate the trachea and lungs. Pleuropneumonia generally manifests when, instead of air, the lungs are filled with inflammatory cells and dead bacteria. The infection causes fever, general malaise, lack of appetite and pain.

Miss Tenacious was attended to by our equine internal medicine specialist Dr Elizabeth Tee and a team of dedicated intern, residents and equine nurses, who undertook a full diagnostic investigation including full blood analysis, thoracic ultrasound and airway video endoscopy.

Blood analysis showed severe inflammation and signs of an infection. Her initial thoracic ultrasound revealed her right lung had an area of infection and a small amount of fluid in her pleural cavity. Video endoscopy also revealed blood tinged pus accumulated in her trachea.

In the last 2-3 months of hospitalisation, the filly spent most of her daylight hours in a large grassy paddock

The results lead the team to immediately start the filly on intravenous fluid therapy, systemic anti-inflammatories to reduce her fever and pain, and systemic antibiotics to combat the infection.

However on the third night of hospitalisation, the filly’s respiratory rate increased further. A second ultrasound showed a sudden deterioration in her chest cavity and lungs and an emergency procedure to drain fluid from her chest was performed that night.

In the first two weeks of hospitalisation, the filly showed a significant lack of appetite and lost a significant amount of body condition, weighing 350kg at the most critical point of therapy.

The team therefore began feeding the filly intravenously with a special hospital formulated liquid diet made up of protein, glucose and fats. The diet in combination with intravenous fluids and antimicrobials improved the filly’s mental activity significantly. Not giving up, Miss Tenacious began to live up to her name, starting to eat and drink on her own.

The challenges faced by the CEC team during her hospitalisation included battling the severe chest infection, nutritional support to improve body condition and prevention of further complications.

In addition to all this, a large amount of fibrin formed in her chest cavity, reducing her body’s and the antimicrobial’s ability to clear her infection. An aggressive intervention program was put in place over several months to treat this additional problem. This included daily drainage of the infected chest fluid, lavaging of the chest cavity with sterile fluid to reduce bacterial load, the administration of a medication called tissue plasminogen activator that helps dissolve fibrin, and daily thoracic ultrasounds to determine progress.

Despite a very severe and persistent infection, the fluid in her chest started to reduce in volume after three months of aggressive intervention. By the fourth month of hospitalisation, the fluid build-up was minimal and the team was finally able to permanently remove her thoracic drains. The infection in her chest slowly resolved over the course of another three months and by the sixth month of hospitalisation, the team was finally able to discontinue her antibiotic therapy.

In the last months of care, the filly would entertaining herself by teasing veterinary interns by galloping around the paddock at top speed while they try to catch her for treatments, then trotting up to them obediently after they were exhausted and out of breath.

The filly also continued to improve in body condition and weight. Six months after hospitalisation she recorded a weight of 490kg, which was 50kg heavier than her initial presenting weight!

Despite a very aggressive and persistent chest infection, it was extremely remarkable that the filly had managed to fend off the infection or not encounter other complications such as severe diarrhoea from an extremely long term use of antibiotics, laminitis or infection of her veins which could have significantly affected her prognosis for life.

After eight months of hospitalisation, the day finally came when Miss Tenacious was ready to be transported back to her home at the magnificent Vinery Stud outside Scone, New South Wales. There she recuperated for a further six months.

Since Miss Tenacious’ ordeal we have received fantastic news that she gave birth to a healthy colt foal in August 2016 to the stallion Dissident, and is set to deliver another with the stallion later in 2017.

The Camden Equine Team would like to thank Mr Greg Perry and the rest of the team at the Vinery Stud who have allowed us to share Miss Tenacious’ story and kindly supplied a six-generation mating profile of Miss Tenacious to the sire Dissident and pictures of the beautiful mare herself.