Muhammad Torequl Islam :
The most commonly reported symptoms of the novel coronavirus disease 2019 (COVID-19) pateints are fever, cough, myalgia or fatigue, pneumonia, and complicated dyspnea, whereas less common reported symptoms include headache, diarrhea, hemoptysis, runny nose, and phlegm-producing cough. Patients with mild symptoms may recover after one week, while severe cases may experience progressive respiratory failure due to alveolar damage from the virus, which may lead to death. Cases resulting in death are primarily middle-aged and elderly patients with pre-existing diseases (e.g., tumor surgery, cirrhosis, hypertension, coronary heart disease, diabetes, and Parkinson’s disease). Case definition guidelines mention the following symptoms: fever, decrease in lymphocytes and white blood cells, new pulmonary infiltrates on chest radiography, and no improvement in symptoms after three days of antibiotics treatment. Physically in severe condition a patient may experience shortness of breath, moist rales in lungs, weakened breath sounds, dullness on percussion, and increased or decreased tactile speech tremor, etc.
The differential diagnosis for SARS-CoV-2 should be distinguished from other known viruses, such as influenza viruses, parainfluenza virus, adenovirus, respiratory syncytial virus, rhinovirus, human metapneumovirus, SARSr-CoV, etc. and also from mycoplasma pneumonia, chlamydia pneumonia, and bacterial pneumonia. In addition, it should be distinguished from non-infectious diseases, such as vasculitis, dermatomyositis, and organizing pneumonia. The diagnosis of a COVID-19 infection is based on the presence of the virus in oro-pharyngeal swabs taken at the right time, as well as on the presence of IgM (and eventually IgG) antibodies against the virus. In severe cases, the diagnosis may be supported by the clinical manifestations of severe respiratory failure syndrome, as well as by blood tests indicating leukopenia, increased liver function tests and high levels of ferritin. Additionally, test for soluble CD-163 (sCD-163) can be done as it represents the activation of macrophages, the level of which increases in meconium aspiration syndrome (MAS) and to parallel the ferritin level. However, the most recommended and popularly used method is performing real-time fluorescence (RT-PCR) to detect the positive nucleic acid of SARS-CoV-2 in sputum, throat swabs, and secretions of the lower respiratory tract samples of the COVID-19 patients.
According to the World Health Organization (WHO) the specimens for virus detection should reach the laboratory as soon as possible after collection. Correct handling of specimens during transportation is essential. Specimens that can be delivered promptly to the laboratory can be stored and shipped at 2-8 °C. The use of viral transport medium is strongly recommended when there is likely to be a delay in specimens reaching the laboratory. Specimens may be frozen to -20 °C or ideally -70 °C and shipped on dry ice if further delays (more than five days) are expected. It is important to avoid repeated freezing and thawing of specimens. However, extracted RNA stored in aqueous solutions, even at -70 °C, is highly prone to degradation. Storage at this temperature is also unreliable as it results power failures, the evaporation of liquid nitrogen or dry ice. Some viruses, such as classical swine fever virus or foot and mouth disease virus can be transmitted directly from animal contact, and indirectly via contaminated equipment, foodstuffs or aerosols. Therefore, shipment on dry ice represents both a biosafety hazard and a general health risk. Furthermore, the requirement to ship on dry ice could be hampered, particularly in underdeveloped countries or regions located far from each other, due to its prohibitive costs.
In the current situation the exchange of viral isolates or field samples remains the critical point in the collaboration among the different diagnostic laboratories. To avoid the problems regarding the conventional system we can use dry pellet matrix. This storage condition is able to protect the RNA-transcript even under more extreme conditions of storage, including higher temperatures and longer periods of time (37 °C for two weeks). It can be proposed as the method of choice for nucleic acid material exchange between different laboratories. In fact, this method is safe and cost-effective and ensures RNA quality for reliable molecular diagnostics.
The most commonly reported symptoms of the novel coronavirus disease 2019 (COVID-19) pateints are fever, cough, myalgia or fatigue, pneumonia, and complicated dyspnea, whereas less common reported symptoms include headache, diarrhea, hemoptysis, runny nose, and phlegm-producing cough. Patients with mild symptoms may recover after one week, while severe cases may experience progressive respiratory failure due to alveolar damage from the virus, which may lead to death. Cases resulting in death are primarily middle-aged and elderly patients with pre-existing diseases (e.g., tumor surgery, cirrhosis, hypertension, coronary heart disease, diabetes, and Parkinson’s disease). Case definition guidelines mention the following symptoms: fever, decrease in lymphocytes and white blood cells, new pulmonary infiltrates on chest radiography, and no improvement in symptoms after three days of antibiotics treatment. Physically in severe condition a patient may experience shortness of breath, moist rales in lungs, weakened breath sounds, dullness on percussion, and increased or decreased tactile speech tremor, etc.
The differential diagnosis for SARS-CoV-2 should be distinguished from other known viruses, such as influenza viruses, parainfluenza virus, adenovirus, respiratory syncytial virus, rhinovirus, human metapneumovirus, SARSr-CoV, etc. and also from mycoplasma pneumonia, chlamydia pneumonia, and bacterial pneumonia. In addition, it should be distinguished from non-infectious diseases, such as vasculitis, dermatomyositis, and organizing pneumonia. The diagnosis of a COVID-19 infection is based on the presence of the virus in oro-pharyngeal swabs taken at the right time, as well as on the presence of IgM (and eventually IgG) antibodies against the virus. In severe cases, the diagnosis may be supported by the clinical manifestations of severe respiratory failure syndrome, as well as by blood tests indicating leukopenia, increased liver function tests and high levels of ferritin. Additionally, test for soluble CD-163 (sCD-163) can be done as it represents the activation of macrophages, the level of which increases in meconium aspiration syndrome (MAS) and to parallel the ferritin level. However, the most recommended and popularly used method is performing real-time fluorescence (RT-PCR) to detect the positive nucleic acid of SARS-CoV-2 in sputum, throat swabs, and secretions of the lower respiratory tract samples of the COVID-19 patients.
According to the World Health Organization (WHO) the specimens for virus detection should reach the laboratory as soon as possible after collection. Correct handling of specimens during transportation is essential. Specimens that can be delivered promptly to the laboratory can be stored and shipped at 2-8 °C. The use of viral transport medium is strongly recommended when there is likely to be a delay in specimens reaching the laboratory. Specimens may be frozen to -20 °C or ideally -70 °C and shipped on dry ice if further delays (more than five days) are expected. It is important to avoid repeated freezing and thawing of specimens. However, extracted RNA stored in aqueous solutions, even at -70 °C, is highly prone to degradation. Storage at this temperature is also unreliable as it results power failures, the evaporation of liquid nitrogen or dry ice. Some viruses, such as classical swine fever virus or foot and mouth disease virus can be transmitted directly from animal contact, and indirectly via contaminated equipment, foodstuffs or aerosols. Therefore, shipment on dry ice represents both a biosafety hazard and a general health risk. Furthermore, the requirement to ship on dry ice could be hampered, particularly in underdeveloped countries or regions located far from each other, due to its prohibitive costs.
In the current situation the exchange of viral isolates or field samples remains the critical point in the collaboration among the different diagnostic laboratories. To avoid the problems regarding the conventional system we can use dry pellet matrix. This storage condition is able to protect the RNA-transcript even under more extreme conditions of storage, including higher temperatures and longer periods of time (37 °C for two weeks). It can be proposed as the method of choice for nucleic acid material exchange between different laboratories. In fact, this method is safe and cost-effective and ensures RNA quality for reliable molecular diagnostics.
(Muhammad Torequl Islam is Assistant Professor, Department of Pharmacy, Life Science Faculty, Bangabandhu Sheikh Mujibur Rahman Science and Technology University. E-mail: [email protected])
