1. Describe the coronavirus structure and clinical features that presents in most cases.
Structure: Coronavirus (Family: Coronaviridae) is the group of viruses that cause disease in humans and other mammals. Morphologically, they look like pleomorphic spherical particles that has bulbous surface projections. Specifically, it has an envelop covering nucleocapsid, and the envelop has spikes. Their average size is 120 nm. The envelope consists of a lipid bilayer, spikes are made of structural proteins (membrane proteins), and nucleopcapsid is composed of positive-sense single-stranded RNA genome. The size of RNA ranges from 26.4 to 31.7 kilobases. An electron microscope image of coronavirus is attached.
Clinical features: According to the recent article by Cascella et al. (2020), the patients with uncomplicated (mild) illness develop symptoms of an upper respiratory tract viral infection which includes mild fever, sore throat, coughing with no mucous discharge, nasal congestion, headache, malaise, and muscle pain. It is important to consider that for mild illness, symptoms of a serious disease such as dyspnea are not present. However, if the situation worsen further, symptoms of moderate pneumonia starts appearing. This includes heavy coughing, shortness of breath (or tachypnea in children). More serious condition develop dyspnea, high fever, respiratory distress, tachypnea (> 30 breaths/min), and hypoxia. Cyanosis can also occur in children. In the rare but extreme cases which leads to death, sepsis may occur which represents a life-threatening organ dysfunction.
2. Identify the specific type of cells that the virus infects inside of the host.
The coronaviruses generally infect mammals and birds. Principally, they need a receptor for the entry purposes. This means that those cells which have these receptors would get infected. These receptors are highly abundant in the respiratory tract cells, which are lined with hair-like projections called cilia whose main purpose is to sweep mucus and bacteria out of the lungs.
3. Describe the mode of transmission and what it means to have an incubation period.
The virus is primarly transmitted via droplets and/or direct contact. This means it can be transmitted via sneezing, couhing, handshaking. Recently, it is stated that it can also spread through breathing and talking. This is the reason that social distancing of 2 meters is encouraged. However, as of today, it is a strong belief that the virus is not airborne unless it is aerosolized. But it is important to consider that it can stay on the surfaces up to 72 hours. Therefore, any contact with contaminated surface would lead to the spread as well. Likewise, if the air is humid and contains droplets, the viral spread is also possible. Numerous other coronaviruses are found to circulate among animals, including camels, cats, and bats as well.
The incubation period is the period between the time of exposure to the time when first symptoms appear. The normal incubation period for coronaviruses is 2 days, however, novel coronaviruses have longer incubation times (up to 2 weeks).
4. Go to the World Health Organization website and find the reported confirmed cases and deaths worldwide as well as in the United States. Provide percent death rate of infection for both, worldwide report and United States report of todays’ date. (Include your date of submission).
As of today (April 8, GMT 2:00 am), I can retrieve the following statistics:
The number of confirmed cases worldwide: 1,514,866
The number of confirmed cases in the United States: 431,838
The number of deaths worldwide: 88,444
The number of deaths in the United States: 14,768.
Death rate worldwide: 5.83%
Death rate in the United States: 3.42%
