Sujana Pokharel
Corona viruses are large, enveloped and positive-stranded RNA viruses possessing the largest genome (ranging from 27 to 32 kb) among all other RNA viruses infecting birds and mammals. These viruses belong to the family Coronaviridae. The virus gains its name "corona" which in Latin means crown. The spike forms large protrusions from the virus surface giving coronaviruses a crown-like appearance. Different studies conducted on corona viruses suggest that they are capable of adapting to new environments through mutation and recombination by altering host range and tissue tropism efficiently.
According to the World Health Organization, the first cluster of Severe Acute Respiratory Syndrome Corona Virus (SARS-CoV) outbreak occurred in China's Guangdong province, in November 2002. SARS-CoV was assumed to be jumped in humans from close contact with civet cats and animals. Similarly, the Middle-East Respiratory Syndrome CoronaVirus (MERS-CoV) outbreak was first reported by the Program for Monitoring Emerging Diseases in Saudi Arabia on September 20, 2012. Like SARS-CoV, MERS-CoV is also a zoonotic virus; the virus is assumed to be jumped from dromedary camels to humans through close contact. CoronaVirus Disease - 19 (COVID-19) is caused by SARS-CoV-2 which stands for Severe Acute Respiratory Syndrome – Corona Virus -2. Initially, this virus was named as 2019-nCoV and further named as SARS-CoV-2 by the International Committee on Taxonomy of Viruses. SARS-CoV-2 was first originated in Wuhan city of China in December 2019 before spreading globally. COVID-19 disease outbreak was declared a pandemic on 11th March 2020 by the World Health Organization (WHO).
According to the Center for Disease Control (CDC), COVID-19 disease is a type of respiratory disease-causing flu-like symptoms with fever, cough and shortness of breath. It is a kind of zoonotic viral disease transmitted originally from bats (Primary host) and pangolins or snakes assumed to be of intermediate host whereas human as a final host. Consumption of meats of those infected animals or through close contact with these animals or their products, this disease is transmitted to a human. Human to human transmission occurs through air droplets and aerosols released by an infected persons during sneezing, speaking, coughing or touching of an infected objects. This disease is looming more than 200 countries in the world. As noted in the WHO website, on 6th May, 2020, there are: 37, 28, 879 corona virus cases, 2, 58,372 deaths and recovered 12, 45,151 cases. According to WHO, on 6th May, 2020, total tests done by PCR were 14,096, RDTs 52,970 out of which 13, 997 were PCR negatives, 99 were PCR positive cases, 19, 734 were in quarantines, 136 were in isolations, total number of recovered patients were 22 whereas no any cases of death till date is reported in Nepal. This disease has being influencing different sectors including health, economic, employment, education, tourism, agriculture, environment and others causing great loss of life and affecting day to day life.
Researchers, scientists, doctors and all the health associated personnel in the world are searching for solutions to get rid of this pandemic. But unfortunately, antiviral drugs and vaccines to treat COVID-19 disease have not been discovered yet which is under investigation. Bio-scientists are focused on breaking the chain of infection for COVID -19. According to WHO, the chain of infection consists of six phases (infectious agent, reservoir, the portal of exit, mode of transmission, the portal of entry and susceptible hosts).
The government is following lockdown, quarantines, social and physical distancing so as to curb the spread of COVID-19. Contact tracing of the COVID-19 suspected person has been done by the government with the help of health personnel however proper mobilization of bio-scientists has not been done yet to achieve good results. Possible biotechnological tools and technique to mitigate COVID-19 pandemic are listed below:
• Rapid diagnostic tests (RDTs)
• Reverse transcriptase real-time PCR (RT-PCR)
• Sero-diagnosis
• Virus culture
• Vaccine trial and antiviral drug discovery
• Inoculation in an animal model
• Cell /tissue culture
• Automated rapid diagnostic technology
• DNA probes and monoclonal antibody
• Gene therapy
• Germ-line therapy
• Recombinant DNA Technology
• Bioinformatics
• ELISA/Radioimmunoassay (RIA)
• Nanotechnology
• Gene sequencing (WGS)
• Use of Artificial Intelligence
• Use of robots and drones
• RNAscope Assay
Among different biotechnological tools, rapid diagnostic tests (RDTs) and reverse transcriptase real-time PCR (RT-PCR) are widely used for diagnosis of COVID-19. Nepal is also using these tests to diagnose COVID-19.
RDT is an indirect identification method for detecting antibodies against COVID-19. RDTs detect both IgM and IgG antibodies among the symptomatic and infected patients. As the name suggests, this testing kit is cheaper, faster, and conducted by health personnel using Personal Protective Equipment (PPE) in fields and normal conditions. Results can be obtained within 15-30 minutes. This single kit can detect only a single sample and specially designed for mass screening tests. Blood is only the choice of specimens for detecting antibodies against COVID-19 using RDTs. RT-PCR is regarded as a gold standard method with high specificity to detect SARS-CoV-2 virus. Unlike RDTs, it detects virus particles (viral RNA) hence called as a direct identification method. Results can be obtained within 60-90 minutes. In this test method, 96 samples can be run on a single batch. Nasal swab, throat swab, oropharyngeal swab, sputum, mid-tubular swab and nasopharyngeal swab, Broncho-alveolar lavage (BAL) fluids additionally stool, urine, blood and serum are the choice of specimens for detecting virus by using this technique. This technique can be used for research purposes rather than for diagnostic one. Since, there is a high chance of misleading results, if there is a lack of proper collection, handling, shipment and processing of viral specimens. According to WHO, RT-PCR must be performed only by trained microbiologists/ biotechnologists under Bio-Safety level -2 (BSL-2) labs or with equivalent facilities. Compared to RDTs, a lab set up to perform RT-PCR is costly and specific manpower is needed. There is a varying and misleading result in both RDTs and RT-PCR tests. Both these methods have their own drawbacks and errors if not properly analyzed and operated. So, one should not rely on a single diagnostic test result (either positive or negative), side by side analysis should be done by evaluating time and duration of performance of test, contact or travel history (present or not) and type of tests performed (RDTs/RT-PCR).
Globally bio-scientists, researchers and different agencies have been continuously investigating communicable diseases like COVID-19. The U.S. National Institute of Allergy and Infectious Diseases (NIAID), studied Remdesivir and they reported it as a proven drug on April 29th, 2020. They presumed that this drug might help COVID-19 patients recover faster by 31%. Remdesivir, developed by Biopharmaceutical Company Gilead Sciences, is the first antiviral drug to show efficacy against coronavirus. This drug is found to block the coronavirus and stops these viruses from making copies of their genetic material. It was originally developed as in Ebola treatment. It is an antiviral drug that mimics a building block of RNA, the corona virus's genetic material, when the virus copies its RNA and incorporates instead of the usual RNA components, stopping the virus's replication.
In a resource-limited country like Nepal, fewer studies and tests have been conducted on COVID-19. Lack of skilled manpower, lack of specificity and sensitivity of testing methods, lack of proper collection, handling, transportation and processing of viral specimens there are misleading results. More than 2,000 microbiologists have graduated from Tribhuvan University. But microbiologists have been facing formidable hurdles due to license to work in the health sectors. In spite of this, Nepal Health Professional Council (NHPC) had issued temporary licenses to the 116 microbiologists in 2011. Afterwards the NHPC does not issue licenses to the microbiology graduates from Tribhuvan University. This is a major weakness of NHPC and Nepal government for the rights that they deserve. Thus, the government should utilize such associated experts like microbiologists and biotechnologists for overcoming this pandemic. On the other hand, collaboration with different fields of bio-science such as bioinformatics, epidemiology, pharmacology, medicines may be very fruitful in conducting research, vaccine development, and antiviral drug discovery in order to mitigate COVID-19 pandemics. Thus, the role of bio-scientists is crucial and inevitable.
(Pokharel is Microbiologists)
