Coronavirus has been declared a pandemic due to COVID-19 confirmed cases around the world. The zoonotic virus causes serious human diseases which include severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome (MERS). The family of coronavirus comprises several viruses. Coronavirus outbreak in the fall of 2019 in Wuhan, China due to severe acute respiratory syndrome (COVID-19).
Coronavirus and its effects
Since its outbreak in December, the virus has spread at a very fast rate causing infection and death all around the world. The mode of transmission of the virus is thought to be by respiratory droplets inhalation although acquisition via the skin surface is another possibility. The symptoms of COVID-19 are fever, later developed respiratory symptoms.
COVID-19 was first identified in Wuhan, China in December 2019. The virus “Coronavirus” belongs to the family of viruses known to cause disease ranging from the common cold to more serious diseases such as the Middle East respiratory syndrome (MERS) & Severe acute respiratory syndrome (SARS).
The most common symptoms of coronavirus are fever, fatigue, dry cough. Other symptoms of coronavirus are soreness, muscle pain, nasal congestion, runny nose, sore throat, and diarrhea. The symptoms are generally mild and start gradually. It caused pneumonia, Severe acute respiratory syndrome (SARS), kidney failure, and even death in most severe cases.
Estimated incubation period range between 2 and 11 days up to a maximum of 14 days. 20% of patients developed severe disease with a high mortality rate and is associated with older age, children, and immunosuppression.
For the collection of useful information about the history of the virus, its transmission diagnosis, clinical features, and radiological findings, research, and development of patients therapeutics and vaccine, the scientist community is working hard. The scientific community is called on to supply fast and coordinate responses to contain the outbreak obtaining reliable diagnostics and optimizing clinical management.
It is crucial that the vaccine is produced sooner before the virus spreads and weakens the health system and the world economy. The most critical issue is to identify COVID 19 infected person, both to promptly assist them and to contain the infection, isolating potential positive subjects. Indeed timely diagnosis, effective treatment, and future preventions are the key to the management of COVID-19.
For the identification of COVID 19 infection RT-PCR is the gold standard to date. Diagnostic kits include serological and immunological essays that largely rely on detecting antibodies produced by individuals as a result of exposure to the virus or on the detection of antigenic proteins in infected individuals.
Structure of COVID-19
The structure of COVID-19 is spherical and spikes (proteins) protruding from their surface. These protein spikes clasp onto human cells, then undergo a structural change that allows the viral membrane to fuse with the cell membrane. Then viral gene entered into the hotel to be copied, replicate more daughter cells of viruses. COVID-19 protein spikes bind to the receptors on the human cell surface and this is called angiotensin-converting enzyme 2 (ACE2).
Molecular testing of COVID-19
For the detection of coronavirus different samples can be tested such as sputum, nasal or throat swabs, endotracheal aspirate, bronchoalveolar lavage, feces, ventricular lavage, and blood.
Detection of a molecular region of the COVID-19 virus
Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) is the gold standard for the detection of the nucleic acid of the COVID-19 virus to date. In the early phase of the infection, the identification is done by the RT-PCR When subject is tested negative in the early phase of infection this is called the “window” period.
The window period is shorter for molecular testing and longer for immunological technologies. Nasopharyngeal swabs and lower respiratory specimens can be used in the molecular technique. All the collected samples should be stored at 2-8° C within five days and if testing takes more time so that after 5 days store the sample under – 70° C.
Antigen detection using Rapid Diagnostic tests
The main aim of the rapid tests is to detect the presence of specific immune proteins in the tested biological fluids. Serum and blood are the common samples used in rapid tests and it provides results within 30 minutes.
In the rapid test, the presence of Immunoglobulin M (IgM) and Immunoglobulin G (IgG) antibodies are detected. On the basis of the presence of antibodies hypothesizing the phase of infection can be determined and it is possible to determine whether the subject is in early, acute or late fees of infection or the subject is healthy.
Clinical findings of COVID-19 infected Patient’s
The first step is the serological test, if the subject tests positive the person should be performed. In the case of false positivity, it is mandatory to examine the lungs both macroscopically and microscopically. Detection of the typical lesson of the COVID-19 infection, so that immunohistochemical investigation and anti-COVID nucleocapsid antibody should be performed with lung samples to determine the molecular data.
If the subject tests negative in the serological tests, the nasal and throat swabs should be taken and if the result is positive, it is mandatory to analyze gross examination, histological investigation, and immunohistochemical analysis of the lung sample. In the presence of clinical symptoms of COVID-19 diseases, if the swab sample is negative, an autopsy should be performed for the confirmation of the molecular results.
Pay attention to the above-mentioned cases because there is a possibility of false-negative in these cases. According to the international recommendations following autopsy should be conducted for COVID-19 positive corpses. Gross and histological examination suspected COVID-19 infection, it is compulsory to perform the immunohistochemical evaluation with anti-COVID 19 and molecular investigations.
On average the symptoms in an infected person take up to 5 to 6 days to be visible, however, it may also take up to 14 days. Common symptoms in infection of coronavirus are fever, dry cough, tiredness. The serious symptoms are difficulty breathing or shortness of breath, chest pain or pressure, loss of speech, or movement.
Other symptoms are aches and pains, sore throat, diarrhea, conjunctivitis, headache, loss of taste or smell, a rash on the skin or discoloration of fingers or toes.
Autopsy findings on different COVID-19 patients
Autopsy findings of a 50-year-old man who was tested positive by real-time reverse transcriptase-polymerase chain reaction (RT-PCR). His lung tissues were examined. Desquamation of pneumocytes, hyaline membrane formation, and Edma indicate acute respiratory distress syndrome (ARDS). Interstitial mononuclear infiltrate and multinucleated syncytial cells are other findings.
Lung biopsies were conducted on two patients infected with COVID-19 infection. Autopsy findings were Proteinaceous exudates in alveolar space, scattered large protein globules, interalveolar fibrin with the presence of inflammatory cells, diffuse expansion of alveolar walls, septa owing to fibroblastic proliferation, type II pneumocytes hyperplasia.
Partial adoption of lung tissues was performed on a pregnant patient infected with COVID 19 infection. The clinical findings are alveolar spaces with a focal hyaline membrane, pneumocyte proliferation, metaplastic changes in the presence of inflammatory cells.
Autopsy of 10 patients infected with COVID-19 infection and tested positive with a nasopharyngeal swab. The histopathological findings are the non-uniform distribution of diffuse alveolar damage (mostly in the inferior and middle lung), hyaline membrane formation, intra-alveolar edema, thickened alveolar septa, perivascular infiltration of plasma cells organized phase with fibroblastic proliferation, parenchymal fibrosis, type II pneumocyte hyperplasia, myocardial T-lymphocytic inflammation associated with interstitial edema and limited focal necrosis.
The histological and immunohistochemical findings of a positive COVID-19 infected patient are the presence of systemic microvascular thrombosis, fibrin deposition within the intra-alveolar septa, and alveolar spaces, hemorrhage, and hemosiderin deposition.
The autopsy findings of patients infected with COVID-19 are infiltration of lymphocyte and small pulmonary arteries, the devoid pattern of vasculitis with a plasma cell, type II pneumocyte (immunohistochemical staining with antibody anti-inflammatory TIFI), pericardial inflammation. The changes in renal are intact glomeruli and acute renal tubular damage. The changes in the spleen and lymph node are cell apoptosis, proinflammatory cytokine expression, the spleen corpuscle are atrophic hyperplasia of interstitial vessels.
The complete autopsies of two patients infected with COVID-19 were performed. The gross examination findings are the presence of massive pulmonary and embolism, the thrombi derived from the deep veins of the lower extremities, fresh deep venous thrombosis without pulmonary embolism, diffuse alveolar damage, presence of hyaline membranes with microvascular thromboembolic, capillary congestion and protein-enriched interstitial edema. On the basis of these findings, they reported cause of death was found within the lungs or the pulmonary vascular system.
Gamaleya Research Institute in Moscow developed Coronavirus vaccine Sputnik V formally known as Gam-COVID-Vac. This vaccine was approved by the Ministry of Health of the Russian Federation on 11th August. This vaccine did not complete its phase 3 clinical trial due to this reason exports raised considerable concern about the vaccine’s safety and efficiency. This vaccine is under phase 3 trials in different countries like Brazil, Abu Dhabi, etc. Are there countries United States of America, India, Abu Dhabi, etc. are in phase 3 trials of their vaccines?
‘By Puru Siddhu’
Puru Siddhu has completed his Bachelor’s in Forensic science from Galgotias Univesity and is currently pursuing his Masters in Forensic Science from IRTE, Faridabad. completed the 5 weeks of Information security course from the University of London. He has completed 45 days of research internship with legal desire media & insights.