According to the Center for Disease and Control:
Coronavirus Disease 2019:
Emergence
COVID-19 was identified in Wuhan, China in December 2019. COVID-19 is caused by the virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a new virus in humans causing respiratory illness which can be spread from person-to-person. Early in the outbreak, many patients were reported to have a link to a large seafood and live animal market, however, later cases with no link to the market confirmed person-to-person transmission of the disease. Additionally, travel-related exportation of cases has occurred.
Transmission
COVID-19 is primarily transmitted from person-to-person through respiratory droplets. These droplets are released when someone with COVID-19 sneezes, coughs, or talks. Infectious droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs. A physical distance of at least 1 meter (3 ft) between persons is suggested by the World Health Organization (WHO) to avoid infection, although some WHO member states have recommended maintaining greater distances whenever possible1. Respiratory droplets can land on hands, objects or surfaces around the person when they cough or talk, and people can then become infected with COVID-19 from touching hands, objects or surfaces with droplets and then touching their eyes, nose, or mouth. Recent data suggest that there can be transmission of COVID-19 through droplets of those with mild symptoms or those who do not feel ill2. Current data do not support long range aerosol transmission of SARS-CoV-2, such as seen with measles or tuberculosis. Short-range inhalation of aerosols is a possibility for COVID-19, as with many respiratory pathogens. However, this cannot easily be distinguished from “droplet” transmission based on epidemiologic patterns. Short-range transmission is a possibility particularly in crowded medical wards and inadequately ventilated spaces3. Certain procedures in health facilities can generate fine aerosols and should be avoided whenever possible.
Symptoms
A wide range of symptoms for COVID-19 have been reported4. These include:
- Fever or chills
- Cough
- Shortness of breath or difficulty breathing
- Fatigue
- Headache
- Nasal congestion or runny nose
- Muscle or body aches
- Sore throat
- New loss of smell or taste
- Nausea or vomiting
- Diarrhea
The estimated incubation period is between 2 and 14 days with a median of 5 days. It is important to note that some people become infected and do not develop any symptoms or feel unwell.