Although those infected with the virus may be asymptomatic, many develop flu-like symptoms including fever, cough, and shortness of breath. Emergency symptoms including difficulty breathing, persistent chest pain or pressure, confusion, difficulty waking, and bluish face or lips; immediate medical attention is advised if these symptoms are present. Less commonly, upper respiratory symptoms such as sneezing, runny nose, or sore throat may be seen. Symptoms such as nausea, vomiting, and diarrhoea are seen in a minority of cases, and some of the initial cases in China presented with only chest tightness and palpitations. In some, the disease may progress to pneumonia, multi-organ failure, and death.
As is common with infections, there is a delay from when a person is infected with the virus to when they develop symptoms, known as the incubation period. The incubation period for COVID-19 is typically five to six days but may range from two to fourteen days
Cause of COVID 19
The disease is caused by the virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), previously referred to as the 2019 novel coronavirus (2019-nCoV). It is primarily spread between people via respiratory droplets from coughs and sneezes. The virus can remain viable for up to three days on plastic and stainless steel, and for three hours in aerosols . The virus has also been found in faeces, but as of March 2020 it is unknown whether transmission through faeces is possible, and the risk is expected to be low.
The lungs are the organs most affected by COVID-19 because the virus accesses host cells via the enzyme ACE2, which is most abundant in the type II alveolar cells of the lungs. The virus uses a special surface glycoprotein, called "spike", to connect to ACE2 and enter the host cell. The density of ACE2 in each tissue correlates with the severity of the disease in that tissue and some have suggested that decreasing ACE2 activity might be protective, though another view is that increasing ACE2 using Angiotensin II receptor blocker medications could be protective and that these hypotheses need to be tested. As the alveolar disease progresses, respiratory failure might develop and death may follow.
The virus is thought to be natural and have an animal origin, through spillover infection. It was first transmitted to humans in Wuhan, China, in November or December 2019, and the primary source of infection became human-to-human transmission by early January 2020. The earliest known infection occurred on 17 November 2019
Because a vaccine against SARS-CoV-2 is not expected to become available until 2021 at the earliest, a key part of managing the COVID-19 pandemic is trying to decrease the epidemic peak, known as flattening the epidemic curve through various measures seeking to reduce the rate of new infections. Slowing the infection rate helps decrease the risk of health services being overwhelmed, allowing for better treatment of current cases, and provides more time for a vaccine and treatment to be developed.
Preventive measures to reduce the chances of infection in locations with an outbreak of the disease are similar to those published for other coronaviruses: stay home, avoid travel and public activities, wash hands with soap and warm water often and for at least 20 seconds (proper hand hygiene and also the time it takes to sing "Happy Birthday to You" twice.), practice good respiratory hygiene and avoid touching the eyes, nose, or mouth with unwashed hands. The CDC recommends covering up the mouth and nose with a tissue during any cough or sneeze and coughing or sneezing into the inside of the elbow if no tissue is available. They also recommend proper hand hygiene after any cough or sneeze. Social distancing strategies aim to reduce contact of infected persons with large groups by closing schools and workplaces, restricting travel, and canceling mass gatherings. Social distancing also includes that people stay 6 feet apart (about 1.80 meters), roughly the length of a full size bed/mattress
According to the WHO, the use of masks is only recommended if a person is coughing or sneezing or when one is taking care of someone with a suspected infection.
To prevent transmission of the virus, the CDC recommends that infected individuals stay home except to get medical care, call ahead before visiting a healthcare provider, wear a face mask when exposed to an individual or location of a suspected infection, cover coughs and sneezes with a tissue, regularly wash hands with soap and water and avoid sharing personal household items. The CDC also recommends that individuals wash hands often with soap and water for at least 20 seconds, especially after going to the toilet or when hands are visibly dirty, before eating and after blowing one's nose, coughing, or sneezing. It further recommended using an alcohol-based hand sanitizer with at least 60% alcohol, but only when soap and water are not readily available. For remote areas where commercial hand sanitizers are not readily available, WHO suggested two formulations for the local production. In both of these formulations the antimicrobial activity of ethanol or isopropanol is enhanced by low concentration of hydrogen peroxide while glycerol acts as a humectant. The WHO advises individuals to avoid touching the eyes, nose, or mouth with unwashed hands. Spitting in public places also should be avoided
Social Distancing is a non-pharmaceutical infection prevention and control intervention implemented to avoid/decrease contact between those who are infected with a disease causing pathogen and those who are not, so as to stop or slow down the rate and extent of disease transmission in a community. This eventually leads to decrease in spread, morbidity and mortality due to the disease. In addition to the proposed interventions, the State/UT Governments may prescribe such other measures as they consider necessary.