SARS-COV-1, SARS-COV-2, AND MERS-COV

SARS-COV-1, SARS-COV-2, AND MERS-COV

Similarities

SARS-CoV-1 means Severe Acute Respiratory Syndrome Coronavirus-1 and discovered in 2002, and it is commonly known as SARS. MERS-CoV means Middle East Respiratory Syndrome Coronavirus and discovered in 2012. SARS-CoV-2 means Severe Acute Respiratory Syndrome Coronavirus-2 and discovered in 2019, and it is commonly known as COVID19 (Rockx et al., 2020). SARS was first discovered in Guangdong province, China, and the scientists are using its pathogenesis to develop the test diagnosis of SARS-COV-2, which was first discovered in Wuhan, China. MERS is caused by coronaviruses, and it was first discovered in Saudi Arabia. The common symptoms for the infection of these three coronaviruses are dry cough, fever, and shortness of breath (Peeri et al., 2020).

These three coronaviruses are airborne and cause a significant number of deaths with a high infection rate among people with concomitant diseases. Although the viruses are causing death, the healthcare givers are also recording a high number of recoveries (Rockx et al., 2020). Studies reveal that the three coronaviruses originate from bats and then transmitted from human to human. All three major coronaviruses are undergoing clinical assessment to develop a vaccine to prevent future infections and pandemic. Moreover, risk assessment studies are ongoing, although most are majoring on SARS-CoV-2, to prevent another outbreak (Peeri et al., 2020).

The testing involves the use of whole-genome sequencing, cell culture, and polymerase chain reaction (PCR). The samples are from the nasopharyngeal epithelial layer and bronchoalveolar fluid. The viruses are transmitted by close human-to-human contact (Rockx et al., 2020). The remedy to prevent further spread involves keeping social distance, wearing of protective face masks, and regular cleaning. The remedy for prevention is similar in all three coronaviruses. The first reported cases for the viruses are receiving criticism from the international world for lack of transparency in reporting the number of cases of the disease, the number of deaths, and the case-fatality rate. For instance, World Health Organization accused China of a lack of transparency in giving credible results of the SARS-CoV-1 in 2002, leading to a high number of deaths and cases of the disease (Peeri et al., 2020).

Differences

SARS-COV-2 as of 7^th April 2020. The worldwide number of people infected with the virus was 1.29 million, and the number of deaths surpasses 76,000. Additional symptoms of a person with SARS-CoV-2 are diarrhea, running nose, and sore throat. SARS-CoV-1 spread only in 29 nations and was contained in July 2003. The SARS infected approximately 8,000 and killed almost 700 people before it was contained in 2003. Additional symptoms of SARS include shivering, myalgia, malaise, and headache. MERS-CoV caused approximately 2,500 infections and 866 deaths before it was contained the following year after discovery (Huang et al., 2020).

The following table compares the epidemiology of the three respiratory viral infections

The COVID19 strain of the virus is still undergoing extensive study, which establishes that the viral pathogens are found on the upper and lower respiratory tract. These reports are from cell culture laboratory results and deep sequencing analysis. PCR analysis has helped in differentiating between COVID19 and SARS strains of the virus. The PCR process targets the pan β-CoV region of the RNA chain, which slightly varies between the two viruses. Diagnostic test kits are also developed from the region that forms the difference in structure (Zhang et al., 2020).

Moreover, the variation of the transcription of the RNA leads to a difference in viral infection, treatment, and development of secondary infections. Up to date, no antiviral vaccine has been developed for the three strains of coronaviruses. The reasons behind this due to the high mutation rate of the viral RNA leading to a lack of the same target region on the virus (Zhang et al., 2020). The virus isolation, especially on MERS, was difficult, leading to delaying in identifying the prophylactic treatment. Most of the patients suffering from MERS and SARS are taking antibiotics to prevent secondary infections. For instance, they are administered with oseltamivir 75mg twice per day with combinations of other corticosteroids to avoid inflammation lung (Zhang et al., 2020). Cases of COVID-19 involve the use of lopinavir and ritonavir to prevent opportunistic infections of hospitalized patients (Callaway, 2020). Cases of MERS involved treatment of lower respiratory infections, whereas cases of SARS and COVID-19 requires treatment of the upper respiratory infections (Huang et al., 2020).

Technological advancement has led to the emergence of sophisticated machines such as RT-PCR, which gives results of RNA isolation within 12 hours. Additional machines that test serum for antibodies have also been developed, which have made it easy for curbing the spreading of COVID-19 (Zhang et al., 2020).  In Saudi Arabia, where MERS was the epicenter used broad-spectrum antiviral nucleotide drug to reduce its efficacy. The treatment of MERS and SARS almost receive similar therapy due to a lack of pre-clinical trials. The laboratories in China and Saudi Arabia confirmed that patients were responding differently after administering a similar drug. For instance, MERS serological tests for IgG antibodies varied among patients in different hospitals in Saudi Arabia. The information is in line with the laboratory tests of SARS in China, whereby the serum antibodies were non-specific to the combination therapy of lopinavir and ritonavir. Even though all the three coronaviruses strains are undergoing similar laboratory tests, the outcome of the results and the potent efficacy for the treatment varies greatly, especially in pre-clinical trials (Huang et al., 2020).

References

Callaway, E. (2020). Coronavirus vaccines: five key questions as trials begin. Nature, 579(7800),

481.

Huang, A. T., Garcia-Carreras, B., Hitchings, M. D., Yang, B., Katzelnick, L., Rattigan, S. M., …

& Lessler, J. (2020). A systematic review of antibody mediated immunity to coronaviruses: antibody kinetics, correlates of protection, and association of antibody responses with severity of disease. medRxiv. 1-47.

Peeri, N. C., Shrestha, N., Rahman, M. S., Zaki, R., Tan, Z., Bibi, S., … & Haque, U. (2020). The

SARS, MERS and novel coronavirus (COVID-19) epidemics, the newest and biggest global health threats: what lessons have we learned?. International journal of epidemiology. 1-11.

Rockx, B., Kuiken, T., Herfst, S., Bestebroer, T., Lamers, M. M., Munnink, B. B. O., … &

Schipper, D. (2020). Comparative pathogenesis of COVID-19, MERS, and SARS in a nonhuman primate model. Science. 1-10.

Zhang, L., Lin, D., Kusov, Y., Nian, Y., Ma, Q., Wang, J., … & De Wilde, A. (2020). α-

Ketoamides as broad-spectrum inhibitors of coronavirus and enterovirus replication: Structure-based design, synthesis, and activity assessment. Journal of medicinal chemistry. 1-17.