| SARS-CoV-2 | Description
Virus that causes Coronavirus Disease 2019 (COVID-19) | Structure
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an enveloped, positive-sense, single-stranded RNA virus belonging to the genus Betacoronavirus within the family Coronaviridae. The viral genome is approximately 30 kilobases in length, making it one of the largest known RNA virus genomes. The virus is characterized by prominent spike (S) glycoproteins projecting from the viral envelope, which mediate attachment to host cells through the angiotensin-converting enzyme 2 (ACE2) receptor. SARS-CoV-2 primarily infects epithelial cells of the respiratory tract but can affect multiple organ systems including the cardiovascular, gastrointestinal, neurological, and renal systems. Since its emergence in late 2019, the virus has evolved into numerous variants through genetic mutation and selection, resulting in changes in transmissibility, immune evasion, and disease severity. | Diagnosis
The diagnosis of SARS-CoV-2 infection is performed through the detection of viral RNA, viral antigens, or virus-specific antibodies. Reverse transcription polymerase chain reaction (RT-PCR) remains the gold standard for the detection of viral RNA in respiratory specimens and provides high sensitivity and specificity. Rapid antigen tests are widely used for point-of-care diagnosis and screening, although they are generally less sensitive than molecular methods. Serological assays, including ELISA-based tests, may be used to detect antibodies generated following infection or vaccination and are useful for epidemiological studies and assessment of immune responses. Laboratory findings in severe cases may include elevated inflammatory markers, lymphopenia, and abnormalities in coagulation parameters. | Symptoms
SARS-CoV-2 is primarily transmitted through respiratory droplets, aerosols, and direct contact with contaminated secretions. Following an incubation period of approximately two to fourteen days, infected individuals may develop fever, cough, fatigue, headache, sore throat, nasal congestion, myalgia, and loss of taste or smell. Additional manifestations may include gastrointestinal symptoms such as nausea, vomiting, and diarrhea. Disease severity ranges from asymptomatic infection to severe pneumonia, acute respiratory distress syndrome (ARDS), multi-organ failure, and death. Elderly individuals and patients with underlying medical conditions are at increased risk of severe disease. Persistent symptoms following acute infection, commonly referred to as post-COVID condition or Long COVID, may affect multiple organ systems and persist for weeks or months after the initial illness. |
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