This time of year, influenza and several other respiratory viruses responsible for the common cold circulate widely. While influenza is responsible for the most fatalities, the other respiratory viruses are capable of producing severe symptoms (and even death) in otherwise healthy persons.¹ Coronavirus is one of these viruses, and for good reason has been receiving much coverage lately.
First isolated in 1965 from patients with the common cold, it quickly became apparent that the virus caused disease in animals as well.² It has been recovered from multiple animals, including chickens, cattle, pigs and bats. While infection with coronavirus is common across species, the virus is implicated in 15-30% of annual upper respiratory infections among humans.
The symptoms, though bothersome, are usually mild and resolve on their own. Most common are headache, malaise, sore throat and fever. There is no approved therapy and as symptoms are mild and self-limited, there was never an aggressive push for one. That is, until the last twenty years.
The WHO identified Severe Acute Respiratory Distress Syndrome (SARS) in 2003 after an outbreak in China. The virus spread person-to-person through droplets (coughing, sneezing, talking) and killed 10-15% of those infected. For persons older than 65 years, the death rate was nearly 50%. Cases were detected as far away as the Middle East and United States, with 8,000 persons infected world-wide.
The last case of SARS occurred in 2004, and coronaviruses slipped back into relative obscurity until 2012 when a new strain was identified in Saudi Arabia. Now known as the cause of Middle East Respiratory Syndrome (MERS), it produced about 2,500 cases with a mortality rate of 34%. At the time of writing, all cases of MERS were acquired on the Arabian Peninsula. Both MERS and SARS are thought to originate from mutated coronaviruses that originally infected bats.
Earlier this year, WHO and CDC officials were notified of a new coronavirus causing pneumonia in Wuhan City, China.³ Initially, patients had been at a large outdoor seafood and animal market but evidence of person-to-person transmission has arisen as well. In the months since its detection, more than 40,500 cases have developed and over 900 people have died. 12 patients in the U.S. have been diagnosed with novel coronavirus (2019-nCOV), most of whom traveled to Wuhan City in the weeks prior. States with current infections include Arizona, California, Illinois, Massachusetts, Washington and Wisconsin. So far, no person in the U.S. has been diagnosed with severe infection.
Typically, symptoms of coronavirus infection take two to four days to manifest. However, it can be as long as 14 days before symptoms of illness develop. During this time the infection can be transmitted to others through respiratory droplets, resulting in new cases. Currently, the CDC recommends screening the following patients:
1. Fever AND symptoms of lower respiratory illness (e.g. cough, shortness of breath), and in the last 14 days before symptom onset:
- History of travel from Wuhan City, China
OR
- Close contact with a person who is under investigation for 2019-nCOV while that person was ill
2. Fever OR symptoms of lower respiratory illness (e.g. cough, shortness of breath), and in the last 14 days before symptom onset:
- Close contact with an ill laboratory-confirmed 2019-nCoV patient
In the meantime, preventative measures offer the best protection. This means frequent hand-washing or use of alcohol-based hand sanitizers. While masks do not prevent breathing in droplets containing virus particles, they can be helpful to reduce frequent touching of your own face. Touching contaminated surfaces and rubbing one’s eyes or nose can cause virus particles to transfer to the hands, which can lead to infection.
If you have become ill after returning from Wuhan City, China or after close contact (within approximately six feet) of a novel coronavirus case for a prolonged period of time, or after having direct contact with infectious secretions of a novel coronavirus case, present to your healthcare provider and notify them immediately.
Reference List
- Troeger C. et al. Estimates of the global, regional, and national morbidity, mortality, and aetiologies of lower respiratory infections in 195 countries, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016. The Lancet. 2018 November; volume 18 (11).
- Bennett J, Dolin R, Blaser M. Coronaviruses, Including Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS). Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 9th Edition.
- 2019 Novel Coronavirus, Wuhan, China. https://www.cdc.gov/coronavirus/2019-ncov/index.html. Centers for Disease Control and Prevention. January 27, 2020.