SINGAPORE: It was a routine day at work for Senior Consultant and Associate Professor Lim Poh Lian at the National Centre for Infectious Diseases (NCID) when events started unfolding which would lead to her suggesting that Singapore could be dealing with its first monkeypox case.

She was on duty on May 7 when a man was brought to the adjacent Tan Tock Seng Hospital (TTSH) with suspected Lassa fever.



Prof Lim said she received a call from the emergency department at TTSH and was told the patient was a 38-year-old man who had arrived from Nigeria on Apr 28.

“I was sitting in clinic seeing HIV patients (when I) got a call from the emergency department saying: ‘I’ve actually got a question about Lassa fever’,” she added.

“The concern that we have has really been around viral hemorrhagic fevers. And there are actually a lot of different exotic infections that come in from all over. And so you can't really be screening for every single thing. But you have to know the travel history (of the patient).”



Image of monkeypox virus magnified (Photo: National Centre for Infectious Diseases)

However, when Prof Lim was told that the patient had rashes on his face and body, she ruled out Lassa fever as the virus does not produce such symptoms. Instead, she started thinking if this could be a case of monkeypox.

NCID was already on the lookout for possible cases, following a major outbreak of the disease in Nigeria in 2017. Tracking of such outbreaks is carried out by the Ministry of Health (MOH) and the NCID, which gather information about emerging infection diseases from around the world. Details are then passed on to frontline doctors about such developments.

Once it was flagged that the man could be suffering from monkeypox, staff at NCID swung into action to confirm it.

"From that point on, the emergency department was on the alert and they admitted him to NCID ... to the negative pressure room as a potential monkeypox case. And then the testing was done, which subsequently confirmed it," said Prof Lim.

“It's one of those challenges when you're seeing cases because we do get a lot of travelers and you can't cry wolf too often.

“So it's a bit of a judgment call. You have to balance it between trying to not under call it but not over call it either. And it's constantly a struggle that we as frontline doctors face,” she added.

PATIENT “RECOVERING WELL”

In a statement issued on Tuesday (May 21), MOH said that the 38-year-old Nigerian man is still receiving treatment in an isolation ward at NCID.

“He is recovering well and is in a stable condition. He will be ready for discharge when he has recovered and is assessed to be non-infectious,” added the ministry.

MOH previously said that the patient had attended a wedding in Nigeria, where he may have consumed bush meat, which could be a source of transmission of monkeypox virus.

Speaking to media at a press briefing last week, executive director of NCID Professor Leo Yee Sin shared that the patient has been warded in a negative pressure room, which is designed to contain dangerous viruses. It features a ventilation system that generates negative pressure to allow air to flow into the isolation room but not escape out.

A negative pressure room at the National Centre for Infectious Diseases, which has a ventilation system that generates negative pressure to allow air to flow in but not escape out. (Photo: Aaron Chong)

Prof Leo also explained that as part of the healing process, scabs will separate from the skin with a new layer grown over the affected areas.

NCID said that the rash usually evolves over a period of 14 days, starting with skin lesions initially on the face as an early symptom, before spreading in a “centrifugal distribution” towards other parts of the body including palms and soles. The rash will then be lump-like, before pus will start to emerge and scabs formed.

NCID added that while there are no vaccines against monkeypox, the body will heal itself “within 14 to 21 days”. However, the disease can be fatal among young children, with a mortality rate of up to 10 per cent.

“He’s (the patient) continued to do very well, he’s very stable. Most of his rash was already dry, except for certain areas, where it’s still a bit blistery-looking, still a little bit moist,” said Prof Leo.

“We will continue to monitor him. This is a very first case, first experience (in Singapore). (What) we can do is from the literature learning in terms of the infectivity periods, to be very safe then we have to wait for all the scabs to dry up and also separate from the skin with a new layer of skin.”

TESTING FOR THE MONKEYPOX VIRUS

Prior to confirming the diagnosis, samples were taken from the affected areas of the patient’s body and sent to the National Public Health Laboratory, also located at NCID.

Associate Professor Raymond Lin, director of the National Public Health Laboratory explained that two kinds of tests were conducted.

The first test called the “polymerase chain reaction” (PCR) test to look for the monkeypox virus gene. The other was to put a sample under an electron microscope to “see the shape and the size of the virus”.

He added that it took around a day before the results were in.

“I think it's fast and it's good enough for action, not to lose the patient as well as will take any other precautions,” said Prof Lin.

He explained that the electron microscope can be used on other kinds of clinical specimens to detect viruses and bacteria, as well as for research to study their structure in greater detail.

