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What do we know about monkeypox and other zoonotic infections?


Monkeypox is a viral infection caused by the monkeypox virus, an enveloped double-stranded DNA virus. It has an incubation period of 7 to 14 days, and symptoms may last from 14 to 16 weeks. It is endemic in several countries and occasionally causes smaller outbreaks.

Monkeypox infection usually starts with fever, malaise, weakness, headache, swollen lymph nodes and chills. It then progresses with a rash that may appear on the face, palms, soles, eyes, mouth, throat, groin or anal regions. The rash begins as a flat lesion or scratch-like wound, grows into fluid-filled vesicles, or blisters, before crusting and drying up. Most cases are mild and self-limiting but the virus can lead to severe illness or death in children, the elderly, or immunocompromised people. A live, attenuated virus vaccine has been developed for smallpox has been shown to be effective against Monkeypox and is offered to those who have been exposed to the virus.

Monkeypox is a type of zoonotic disease, which happens when infections occur between vertebrate animals and humans. Zoonoses can be viral, bacterial, parasitic, fungal in origin or transmitted by proteins known as prions, which can be further classified based on the transmission pattern. For example, rabies is a direct zoonosis between vertebrate animals to humans, while tapeworm is a cyclozoonosis between more than one vertebrate animal to humans. We also have infections like Lyme disease, which is a metazoonosis between both vertebrates and invertebrates to humans; and histoplasmosis, which is a saprozoonosis between vertebrate animals and an inanimate developmental site such as food or soil to humans.

Zoonoses are important to pay attention to because they are closely tied to emerging infectious diseases. Factors such as urbanisation, deforestation, climate change, travel and trade activities are the main drivers of emerging zoonotic infections. As the risk of spillover infections from natural animal reservoirs to humans is high, it is important to have proper preventive measures in place to prevent these spillover events.

Dr Khoo Yoong Khean
Scientific Officer, Duke-NUS Centre for Outbreak Preparedness

Monkeypox is a zoonotic infectious disease caused by the monkeypox virus (MPXV), which belongs to the same cluster of viruses as smallpox. It was discovered in laboratory monkeys in 1958, and the first case of monkeypox in humans was reported in Central Africa in 1970. Since then, the virus has been circulating in Central and West Africa for decades. Monkeypox is spread through close contact with infected persons or animals, or exposure of cuts and mucous membranes to infected saliva, respiratory droplets, or bodily fluids.

Following the eradication of smallpox in 1980, human MPXV outbreaks have occurred in the United States in 2003 and Nigeria in 2017. Sporadic human cases have also been detected in countries including Singapore (in 2019) and the United Kingdom (in 2018). However, the emergence of a novel human MPXV lineage in 2022 has initiated an unprecedented outbreak of monkeypox, which has spread rapidly to at least 85 countries with more than 31,800 confirmed cases globally (as of 09 August 2022).

Unlike SAR-CoV-2, monkeypox is a double-stranded DNA virus which typically mutates much slower than RNA viruses. The MPXV consists of a large genome, about 197 kilobases in length, which is more than six times the size of the SARS-CoV-2 genome. Although the natural reservoir of MPXV is unknown, it is believed to be of animal origin. As with most zoonotic viruses that jump from one species to another, genetic changes are likely to have occurred for the virus to adapt to a new species.

To date, three genetic lineages of MPXV have been identified, and recent genetic analyses indicate that the novel 2022 outbreak lineage is derived from a clade comprising the earlier strains detected in Nigeria, Singapore and the UK from 2017 to 2019. The novel 2022 strain contains 47 nucleotide changes compared to other related viruses, but more research is needed to understand if these mutations are associated with virus-host adaptation.

Associate Professor Yvonne Su
Duke-NUS Emerging Infectious Diseases Programme

Cancer immunotherapy

Is immunotherapy for cancer still an active field of research? Have we found all possible targets?


To answer very simply, immunotherapy is most definitely still an active field of research.

For over 60 years, cancer patients have been treated with chemotherapy to break the DNA of cancer cells to prevent them from splitting and multiplying.

Immunotherapy for cancer, on the other hand, makes use of the patient’s immune system to attack the cancer cells. Like a wolf in sheep’s clothing, cancer cells try to trick immune cells into thinking that nothing is amiss by producing “don’t eat me” signals. By treating patients with drugs such as antibodies to disrupt these signals, we can release the brakes on the immune cells, enabling them to see through the disguise and kill the cancer cells. Another cell-based technique involves altering the genes in immune cells known as T cells to help them attack the cancer cells.

We must remember that it was only in 2018 that the Nobel Prize in Physiology or Medicine was awarded to scientists, James Allison and Tasuku Honjo for their pioneering work on immune checkpoints that involved finding these targets on immune cells that can unleash their ability to kill the cancer. We are just at the end of the initial phase of our work in immunotherapy research and there are still many more targets to find in this field to add to our arsenal of weapons against cancer.

Associate Professor Toh Han Chong
Deputy Chief Executive Officer (Strategic Partnerships) and Senior Consultant, Division of Medical Oncology, National Cancer Centre Singapore
Academic Vice-Chair, Academic Partnerships,
SingHealth Duke-NUS Oncology Academic Clinical Programme

How long does it take to become a clinician-scientist?

How long does it take to become a clinician-scientist?


The short answer is that, at Duke-NUS, we have an MD-PhD Programme that provides formal training for a future career as a clinician-scientist. This course takes seven to eight years to complete, and is designed for students who already have an undergraduate degree. Alternatively, for those who are already clinicians, Duke-NUS also offers a Clinical and Translational Sciences PhD progamme, which can be pursued after obtaining your medical degree. This programme prepares medical specialists for clinical and translational research, and takes about three to four years to complete.

What do you gain from the additional years of training?

Here’s the long answer. Let’s first define a clinician-scientist: a clinician-scientist is a clinician who devotes a significant portion of his/her professional time toward scientific pursuits. Such individuals have received additional training to conduct formal scientific studies that improve and advance healthcare. What makes clinician-scientists unique is their knowledge of clinical medicine, which when combined with their scientific skills, enables them to ask important medically related questions—and to pursue scientifically sound approaches to efficiently address those knowledge gaps. 

In broad terms, formal scientific training will include but is not limited to the following: the development of a deep knowledge within the area of study, the ability to read and evaluate scientific literature, and the ability to formulate insightful scientific hypotheses, design experiments that rigorously test those hypotheses, and properly interpret the results of those experiments.

Understandably, only those who are very interested in both science and medicine will take the additional time to pursue combined medical and scientific training. However, if you are someone who is scientifically curious, loves looking after people, doesn’t mind working hard, is driven to make impactful discoveries that ‘transform medicine and improve lives’, and can persevere through delayed gratification in pursuit of a worthy and important goal, this might just be the career for you!

Associate Professor Ong Sin Tiong
Duke-NUS MD-PhD programme director
Duke-NUS Cancer and Stem Cell Biology Programme 

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