There is more to coronavirus that meets the eye. Apart from scientists, researchers, and doctors, most people didn’t know much about coronavirus, until Covid-19 breakout. A lot of research, studies, and clinical trials have taken place for some time now, in a bid to understand coronavirus better. The studies have revealed several strains of the virus, some of which can be transmitted from non-human hosts to human hosts.
So far, seven strains of coronaviruses have been established to cause disease in humans. On the other hand, there are delta and gamma strains that are not known to cause human disease. Research has established that three stains, namely SARS-CoV, MERS-CoV, and SARS-CoV-2 (COVID-19), can be transmitted from non-humans to humans.
1. Severe acute respiratory syndrome (SARS)
The SARS pathogen is airborne, spread through droplets containing the virus. Coronavirus causing SARS is different from other coronaviruses known to cause human illnesses. One of the ways that SARS is unique is the fact that it is RNA enveloped. The virus is known to cause fatal and severe respiratory illness among humans. The first case was reported in China in 2002. However, there has been no known infection since 2004.
SARS is characterized by symptoms such as coughing, fever, sneezing, muscle ache, and headache. No cure for the virus had been found and was only treated through supportive care. SARS is thought to be an animal virus as data from studies demonstrate the prevalence of the virus among animal traders. The animal hosts are presumed to be muntjac deer, pheasants, hare, and civets. It is known to spread fast among humans through close contact.
2. The Middle East Respiratory Syndrome Coronavirus (MERS-CoV)
Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is a coronavirus strain known to spread among humans, bats, and camels. Just like SARS, it is an RNA-enveloped virus, that binds the DPP4 receptor. The first case of MERS-CoV was reported in 2012, from a sputum sample that was collected from a person who had fallen ill in the same year.
MERS-CoV cases increased with time, and by July 2015, it had spread in most countries in the Middle East (over 21), Austria, and the United Kingdom. The virus also spread in America, and some parts of Asia like Indonesia and the Philippines.
The fatality rate of MERS was declared 30% having caused 600 deaths among 2000 reported positive cases. Studies demonstrated that the virus had a strong tropism for non-ciliated bronchial epithelial cells. The virus has also been found to be very evasive of the innate immunity, something which makes it one of the unique coronaviruses.
Studies revealed that the response across different species of hosts differed. For instance, the immune response of bats to coronaviruses showed a high degree of evolution. As a result, MERS-CoV lineage may have taken a lot of time circulating before being transmitted to humans.
Observations made of the rate of transmission of the virus among healthcare workers led to the conclusion that the virus took place in people in close contact. The studies further revealed that the virus was prevalent among people who were in close contact with camels and ate camel meat. Researchers are yet to establish how exactly MERS spreads among humans, but there is ongoing research geared at understanding the virus better. The treatment for MERS mainly involves supportive care for the function of vital organs: there is no anti-viral treatment that has been established.
3. Covid-19 (SARS-2-CoV)
Covid-19 was first described in Wuhan, Chine, in 2019. The origin of the virus is yet to be established, but it is believed to have originated from bats and pangolins. The mode of spread is similar to the other reported coronaviruses, which are SARS and MERS. That is being in contact with infected persons, touching contaminated surfaces, and air transmission.
SARS-CoV-2 spreads faster and quickly compared to MERS and SERS. This has been demonstrated by the number of positive cases that have been so far recorded across the globe. The other difference that exists is the severity of this strain of coronavirus. It appears to be severe compared to MERS, which recorded a fatality rate of 30%. Covid-19 has so far demonstrated a severity rate of about 0.5%-1%.
Covid-19 is also an RNA-enveloped virus. There have been many reported cases across the globe, except for Antarctica. People aged 65 years and above, and especially those with comorbidities, have demonstrated a faster rate of infections and severity of the symptoms. Investigational data has shown that the male population has been the most affected compared to the female population. Studies are still underway to find a vaccine and cure for Covid-19.
The treatment available do far is supportive care, just like for the case of preceding coronaviruses. Scientists are yet to establish whether the spread and prevalence of the virus are seasonal like other coronaviruses.
Paul Singh, MHA, BA
Covid Antibody Diagnostics™
A Natures Body Wellness Corporation, Lake Mary FL 32746
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