Individuals in pastoral regions are advised to be keen as they interact with stock to avoid contracting diseases, among them the Middle East Respiratory (MERS) syndrome.
MERS is a zoonotic disease caused by MERS-Coronavirus (MERS-CoV), a virus that infects both animals and humans, with close linkage to camels. MERS was first reported in humans in Saudi Arabia in 2012. MERS-CoV is related to both SARS-CoV which emerged in Hong Kong in 2002 and SARS-CoV-2 which is responsible for the Covid-19 pandemic.
According to Brian Maina Ogoti a PhD Fellow at the Center of Epidemiological Modelling and Analysis, University of Nairobi in collaboration with Charité – Universitätsmediz in Berlin, current evidence of the origins shows that bats are likely the original source of MERS-CoV.
“Bats are considered natural hosts for many coronaviruses, and they likely jumped from bats to camels before being transmitted to humans, MERS-CoV likely spilled over from bats to dromedary camels at least 30 years ago and since then has been prevalent in this type of camels,” says Ogoti.
Ogoti notes that human-to-human transmission of MERS-CoV does occur but is less efficient than some other respiratory viruses such as influenza or common cold coronaviruses.
Most human-to-human transmission occurs in healthcare settings and among close family members or caregivers of infected individuals. The largest outbreaks have occurred in healthcare facilities in Saudi Arabia, the United Arab Emirates, and the Republic of Korea.
Approximately 80 per cent of human cases have been reported in Saudi Arabia because of direct or indirect contact with infected dromedary camels or infected individuals in healthcare facilities. Ogoti adds that MERS-CoV can be a serious disease, especially for individuals with underlying health conditions and weakened immune systems.
The symptoms can range from asymptomatic, or mild respiratory symptoms to severe respiratory disease which can result in death. Symptoms can include fever, cough, and shortness of breath.
Though the disease affects all ages, “elderly people with weakened immune systems or have other conditions such as diabetes, cancer, or hypertension among other chronic illnesses appear to be at a higher risk of developing severe disease”. The death rate for MERS is relatively high, with up to about 34 per cent.
“MERS-CoV is primarily spread through close contact with infected camels or their bodily fluids, especially saliva and their nasal secretions
He adds, “There is also evidence of self-limiting human-to-human transmission occurring through respiratory droplets generated when an infected person coughs or sneezes”.
There have been a total of 2,605 human cases with 936 associated deaths reported in 27 countries in Africa this year, cases associated with recent travel to the Middle East, with only a single study in Kenya reporting low-level MERS-CoV PCR.
Despite the high number of camels in Africa, only a few zoonotic MERS-CoV cases have been detected in humans. Efforts to develop an effective and safe human MERS-CoV vaccine have progressed, with a few vaccine candidates having reached human clinical trials/studies.
“The RNA technology recently used to develop SARS-CoV-2 vaccines is also being adopted for the development of MERS-CoV vaccines,” says Dr Ogoti.