COVID-19: An up-to-date review - from morphology to pathogenesis

The entire world is under a devastating pandemic caused by COVID-19 with a high mortality rate. Knowledge of the viral structure, factors that help in its progression and spread, pathological findings, diagnostic methods and, treatment modalities helps in understanding the viral disease and also in treating the patients in a better way besides preventing the community spread of this deadly infection. The causative agent is a single- stranded RNA virus. The clinical spectrum varies in symptomatic and asymptomatic patients, who later become potential silent carriers, thus unknowingly spreading the virus. The virus constantly undergoes recombination, with reports of cross-species infections. Studies have indicated a strong immunological basis of COVID-19 infection. Not only does it weaken the immune system causing multi-organ involvement but also helps in its progression and spread to others.Multiple organs especially lungs, heart, kidney, gastrointestinal and hepatic system, brain and skin are affected varying in their severity. Similarly, persons with associated co-morbidities are likely to be affected more in terms of the number as well as in the severity. Real- time reverse transcription polymerase chain reaction confirms the presence of COVID-19 infection. Serological diagnosis helps in diagnosing an ongoing outbreak or retrospective infection. Furthermore, it also identifies individuals who have been infected or have recovered from the disease especially the asymptomatic. This helps in the development of an effective vaccine indicating the status of herd immunity in the community. Different treatment modalities are being tried and under trial. This review article thus highlights the global epidemiological status, characteristic of the virus, symptomatology of the patients, role of diagnostic tests available, organs affected including their morphological changes and the latest line of treatment of COVID-19.