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A study of samples collected in Manaus between November 2020 and January 2021, indicated that the Gamma variant is 1.4–2.2 times more transmissible and was shown to be capable of evading 25–61% of inherited immunity from previous coronavirus diseases, leading to the possibility of reinfection after recovery from an earlier COVID-19 ...
Viral pathogenesis is the study of the process and mechanisms by which viruses cause diseases in their target hosts, often at the cellular or molecular level. It is a specialized field of study in virology. [1] Pathogenesis is a qualitative description of the process by which an initial infection causes disease. [2]
The most similar known viruses to SARS-CoV-2 include bat coronaviruses RpYN06 with 94.5% identity, [15] and RmYN02 with 93% identity [18] RaTG13 was not the direct progenitor of SARS-CoV-2. [19] Temmam et al. found no serological evidence for exposure to BANAL-52 among bat handlers and guano collectors in the area of Laos where it was sampled ...
The transmission of COVID-19 is the passing of coronavirus disease 2019 from person to person. COVID-19 is mainly transmitted when people breathe in air contaminated by droplets/aerosols and small airborne particles containing the virus. Infected people exhale those particles as they breathe, talk, cough, sneeze, or sing.
The human coronavirus NL63 shared a common ancestor with a bat coronavirus (ARCoV.2) between 1190 and 1449 CE. [76] The human coronavirus 229E shared a common ancestor with a bat coronavirus (GhanaGrp1 Bt CoV) between 1686 and 1800 CE. [77] More recently, alpaca coronavirus and human coronavirus 229E diverged sometime before 1960. [78]
Transmission electron micrograph of SARS‑CoV‑2 virions (red) isolated from a patient during the COVID-19 pandemic. A distinguishing feature of SARS‑CoV‑2 is its incorporation of a polybasic site cleaved by furin, [102] [112] which appears to be an important element enhancing its virulence. [113]
The relationship between virulence and transmission is complex and has important consequences for the long term evolution of a pathogen. Since it takes many generations for a microbe and a new host species to co-evolve, an emerging pathogen may hit its earliest victims especially hard.
Coronavirus diseases are caused by viruses in the coronavirus subfamily, a group of related RNA viruses that cause diseases in mammals and birds. In humans and birds, the group of viruses cause respiratory tract infections that can range from mild to lethal.