What's your hobby? How many pets do you have? What did you do on your holiday?
In most conversations, they would pass for harmless small talk. For infectious diseases specialist Assistant Professor Shirin Kalimuddin, they can be the first clues in a case that refuses to give itself away.
A patient’s travel history. An offhand remark. A seemingly forgettable detail that turns out to matter. Over the years, Kalimuddin has built her career on listening closely, noticing what others miss, and following seemingly minor details until they reveal something far more consequential. This is crucial to her work at the Department of Infectious Diseases at the Singapore General Hospital (SGH) and the Duke-NUS Emerging Infectious Diseases Programme.
It is a kind of detective work, though not the dramatic sort popularised by Dr Gregory House in House, M.D. Kalimuddin is not swabbing kitchen sinks or rummaging through medicine cabinets. Her method is quieter, but no less exacting: ask carefully, listen deeply, and piece together what is hiding in plain sight.
That same relentless instinct has carried her to venture beyond the hospital ward and into the research lab, where she now applies the same rigour and ingenuity to understanding the host immune response to viral infections, a transition that was fully supported by one of her earliest mentors, Professor Jenny Low.
"She’s very good at making sure that the ‘diamond’ in every project shines"
Clin Assoc Prof Oh Choon Chiat
“Shirin made the right decision to go down research because I think she has the right temperament and intellectual rigour for it. I think she would have been equally successful even if she had chosen another path,” added Low.
Kalimuddin’s long-time colleague and head of the SGH Department of Infectious Department, Clinical Associate Professor Limin Wijaya agrees: “She is curious and creative and is proactive in translating ideas to outcomes. This is very important in academia.”
A dream since childhood
From a young age, Kalimuddin wanted to become a doctor.
While other kids were playing house, she was busy running a make-believe clinic, with her younger sister as her patient. “I would hook her up to all these like...fake drips, tubes and all,” said Kalimuddin, with a grin.
She hit a temporary roadblock, however, when she didn’t get into medical school in Singapore.
Undeterred, Kalimuddin applied to study overseas—and with her parents’ support, pursued medicine at King's College London.
“I think that was a blessing in disguise because the opportunity to go overseas and see a different system enabled me to become more independent and open to alternative ways of doing things,” said Kalimuddin, reflecting on her stint as a medical student and then house officer in the United Kingdom.
When it came time to apply for residency training, Kalimuddin and her then-partner, now-husband found themselves at the crossroads.
Realising that staying meant being posted to opposite ends of the country, the pair made the pivotal decision to return home to complete their training.
Going the diagnostic route
So, in 2007, Kalimuddin touched down on home soil on National Day, a date that marked the start of her new adventure.
Her first posting upon returning was to the Department of Rheumatology at the Singapore General Hospital.
But it was a subsequent posting to the Internal Medicine department that led Kalimuddin to discover her calling in infectious diseases.
While infectious diseases existed as a niche service within the department back then, the experience treating patients with unexplained symptoms drew Kalimuddin to the field.
“I like the diagnostic aspect of it,” she explained. “The fact that we often don’t know what’s wrong with the patient and it’s ID (infectious diseases) that comes in and puts all the pieces together—I find it really fascinating. It’s like you’re in a detective story happening in real time.”
Cracking cases in the ID realm
Most of the patients Kalimuddin sees are “blue letters”, or referral cases who present with prolonged fevers among other symptoms.
“There’s always this joke that the ID physician will come and summarise it all. Like if the team doesn’t know what’s going on, they will call ID,” chuckled Kalimuddin.
Because of that, her patients come from a range of specialties, from medicine to surgery.
“We need to understand a little bit about what kind of surgery they’ve had, what drug they’re on and so on,” said Kalimuddin, stressing the importance of understanding these details, which help her team in diagnosing the patient and mapping out treatment options.
In most instances, the diagnosis does not point to an underlying sinister infection but other conditions such as cancer that cause prolonged fevers.
But there are still exceptions, like one of Kalimuddin’s earliest cases as a young medical officer: a patient who returned from the Hajj pilgrimage with a fever that had been running for several weeks.
“That’s when we found out that she’d gone on this tour and then visited a farm where they drank raw camel milk,” added Kalimuddin excitedly, emphasising the importance of taking the patients’ history. “So it’s not just where did you go, but also what did you do.
The crucial missing piece of the puzzle: camel’s milk //Credit: iStock.com / Nataliia Milko