Doctors issue warning after teenage girl contracts deadly disease from horses in Limerick
Darragh Mc Donagh
Doctors in Limerick have issued a warning after a teenage girl contracted a rare and potentially deadly disease from horses.
The 17-year-old was hospitalised and required six weeks of intravenous antibiotics after she presented at the emergency department of University Hospital Limerick (UHL) with a range of painful symptoms.
She was eventually diagnosed with Streptococcus equi – a rare bacterial infection that causes strangles in horses and can be lethal in humans, although zoonotic transmission is uncommon.
Human infection can cause bacteremia, which may result in sepsis or septic shock. It can also cause a rare muscle disease called myositis, and swelling of the bones. The bacteria can also infect heart valves, and cause septic arthritis.
It is particularly dangerous for immunocompromised individuals, people with diabetes, and newborns, with mortality rates in these groups ranging from 33 per cent to 66 per cent.
The teenager attended UHL after feeling unwell for around a week, complaining of a sore throat, cough, and fever. These symptoms had improved after two days, so she participated in a horse grooming show.
However, she fell ill again after the show, developing a rash on her left leg, as well as painful swelling that caused her to limp.
She tested positive for influenza B virus and was told to self-isolate and rest. But subsequent blood tests revealed the presence of Streptococcus equi and she was readmitted.
The girl was diagnosed with bacteremia – bacteria in the bloodstream that can cause septic shock – along with left lower limb cellulitis, and myositis. The infection was treated with six weeks of intravenous antibiotics.
An MRI two months later showed significant improvement, but she still had mild residual myofascial edema – swelling of the muscles and surrounding tissues.
In a case report published in the latest issue of the Irish Medical Journal, doctors at UHL warned that comprehensive history-taking was vital to expedite diagnosis and treatment of Streptococcus equi.
They suspected that the original influenza B infection had caused immunosuppression, facilitating the transmission of the bacteria to the girl from the horses that she was grooming.
“This case highlights the impact of transient immunosuppression, potentially induced by the influenza B virus infection, on the severity of S. equi infection,” they wrote.
“Furthermore, it emphasises the importance of a thorough clinical history to prevent diagnostic delays and suboptimal outcomes.”
