MERS crisis: first comprehensive study in Africa
MERS coronavirus, a virus related to but not identical to SARS coronavirus, causes severe pneumonia with high fatality and is a global public health concern. Since its discovery in 2012, over 2,100 laboratory-confirmed cases have been reported with more than one-third of these being fatal.
An outbreak in South Korea in 2015 resulted in 186 cases and had a significant impact on the South Korean economy. The animal source of human infection is the dromedary camel. The virus is also found in camels across East, North and West Africa but humans have not known to acquire MERS from camels in Africa. The reason for this has remained unclear.
To investigate further a team of researchers from the University of Hong Kong led by Professor Malik Peiris (Croucher Senior Medical Research Fellowship 2005) and including Professor Leo Lit Man Poon (Croucher Senior Research Fellowship 2017, Scholarship 1996) , and Dr Kenrie Pui Yan Hui (Croucher Studentship 2006) designed a groundbreaking study.
The team coordinated and led a multi-national research consortium of scientists from multiple countries in Africa, Saudi Arabia, China, Europe and the USA to study MERS-coronaviruses in camels in West (Nigeria, Burkina Faso), North (Morocco) and East (Ethiopia) Africa. They coordinated the collection and analysis of 2,609 samples from camels in multiple African countries. They confirmed that MERS coronavirus infection was as common in camels in Africa as it was in Saudi Arabia. They found that the MERS coronaviruses from Africa were genetically very similar to, but distinct from, those in the Arabian Peninsula. Detailed investigation of viruses from West Africa showed that they had reduced ability to infect the human respiratory tract and to replicate in the lungs of mice made susceptible to MERS coronavirus infection. The researchers conclude that the MERS-coronaviruses from West Africa may pose a lower risk to humans.
It is important to understand whether MERS coronaviruses in Africa pose a significant threat to human health. Over 70% of the global dromedary camel population is found in Africa. The study shows that these camels are as commonly infected by MERS-coronavirus as are camels in the Arabian Peninsula. If MERS coronaviruses from Africa are similar to those in the Arabian Peninsula in their risk to humans, current public health measures would have to be reassessed; advice to travellers to multiple African countries would need to be modified and doctors would need to be warned to be alert for MERS in travellers returning from Africa, as well as the Arabian Peninsula.
Prof Peiris who led the study says, “Although we found that MERS coronaviruses are as common in camels in Africa as in those in the Arabian Peninsula, the African viruses are genetically different; and in particular, the viruses from West Africa which we have studied in detail appear to be less able to infect the human respiratory tract.”
Prof Leo Poon says, “Our research suggests that West African MERS coronaviruses may pose lower threat to humans but more research is urgently needed on MERS coronaviruses in Africa, especially those from East Africa”.
The findings are published in Proceedings of the National Academy of Sciences.