Coronavirus infections are commonly associated with the common cold but can also cause pneumonia and other lung diseases. There are an estimated 180 million cases/year in the United States. In 2019, a coronavirus, SARS-CoV-2, caused a pandemic of respiratory illness, called COVID-19.
CASES/YEAR
180,000,000 (US); 3,600,000,000 (Global)
OTHER NAMES
Severe acute respiratory syndrome (SARS); Middle East respiratory syndrome (MERS); COVID-19 (SARS-CoV-2);
INCUBATION
2-7 days (range of 1-14 days); [Harrison ID, p. 777]
INITIAL SYMPTOMS
See "Upper respiratory tract infections." SARS: myalgia, fever, cough, dyspnea, lung infiltrates, and ARDS; [CCDM] For symptoms of Covid-19, see https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/symptoms.html
PRECAUTIONS
SARS: Contact + Droplet + Airborne for duration of illness plus 10 days after resolution of fever, provided respiratory symptoms are absent or improving. "Airborne Precautions preferred; D if AIIR unavailable. N95 or higher respiratory protection; surgical mask if N95 unavailable; eye protection (goggles, face shield); aerosol-generating procedures and 'supershedders' highest risk for transmission via small droplet nuclei and large droplets. Vigilant environmental disinfection (see www.cdc.gov/ncidod/sars)." [CDC 2007 Guideline for Isolation Precautions] "Health workers are at greatest risk of transmission, especially before the diagnosis of SARS is made and when involved in aerosol-generating procedures such as intubation or nebulization." [CCDM, p. 542]
COMMENTS
"[Non-SARS] coronavirus infections are commonly associated with acute respiratory illnesses that are usually mild and consistent with the common cold but can also result in the full range of acute respiratory illnesses including pneumonia, croup, bronchiolitis, and bronchitis." [Cecil, p. 2165]
SARS:
This new disease was first reported by the Chinese Ministry of Health to the World Health Organization on February 11, 2003. By July of 2003, 8098 cases in 29 countries with 774 deaths had been reported. This previously unrecognized coronavirus infection (SARS-CoV) is transmitted to healthcare workers and household contacts. Approximately 10-20% of patients develop respiratory failure requiring intubation and mechanical ventilation. The case fatality proportion is 9.2%. Patients develop either: 1) none to a few mild symptoms; 2) moderate illness; or 3) severe disease. In severe cases, the chest x-ray may show atypical pneumonia, and blood analysis may show decreased lymphocytes and platelets. "By late July 2003, no new cases were being reported, and WHO declared the global outbreak to be over." [CDC website] Civets and other wildlife were thought to be reservoirs of SARS. [CCDM, p. 541] The initial symptoms in SARS were fever, usually with headache and myalgia. Nonproductive cough followed several days later. Diarrhea occurred in 25% of patients, and rhinorrhea and sore throat usually did not occur. [PPID, p. 2078] Less common symptoms are sputum production, pharyngitis, rhinitis, vomiting, and diarrhea. Petechiae, orchitis, and seizures may occur. Typically, the fever pattern is biphasic. Usually absent on the chest x-ray are cavitations, hilar lymphadenopathy, and pleural effusions. [Guerrant, p. 394-5] The horseshoe bat appears to be the reservoir, and the outbreak may have been started by contact with palm civets (semi-domesticated animals). [Harrison ID, p. 776] "To reduce the risk of introducing severe acute respiratory syndrome (SARS) coronavirus, civets and related animals (family Viverridae) may not be imported into the United States." [CDC Travel, p. 671] See "How should a positive PCR test result for COVID-19 in an asymptomatic individual be interpreted and managed?" [PMID 33022291]
MERS:
MERS-CoV (Middle East Respiratory Syndrome coronavirus virus) is a new strain of coronavirus. Information is still incomplete on how it is spread, the range of illness, and the source. As of June 2013 there have been over than 60 cases detected--the majority of these in Saudi Arabia. Most cases present with fever and cough that progress to a severe pneumonia with a 50% mortality rate. Renal disease and diarrhea have been a feature of some cases. "Severe acute respiratory syndrome (SARS) was caused by virus from the same family of coronaviruses as MERS-CoV but a different unconnected subtype." [Public Health England website] "By June 11, 2014, 699 laboratory confirmed cases, including at least 209 deaths had been officially reported to WHO." [CCDM, p. 546] ". . . Health care providers should evaluate patients for MERS if they develop fever and pneumonia or acute respiratory distress syndrome within 14 days after traveling from countries in or near the Arabian Peninsula or have had close contact with a recent traveler from this area who has fever and acute respiratory illness." [CDC Travel, p. 299]
DIAGNOSTIC
Nose and throat swabs: Culture; PCR assays commercially available; Blood: Paired sera; [CDC website: Coronavirus]
SIGNS & SYMPTOMS
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>fever
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>fever, biphasic or relapsing
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>myalgia
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E pharyngitis
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E rhinitis
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G diarrhea
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G liver function test, abnormal
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G nausea, vomiting
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H leukopenia
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H thrombocytopenia
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N headache
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N seizure
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R cough
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R dyspnea
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R sputum production
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R wheezing
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S petechiae and ecchymoses
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X lung infiltrates
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*ARDS
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*epididymo-orchitis
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*pneumonia
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*rhabdomyolysis
ENTRY
Inhalation, Skin or Mucous Membranes (Includes Conjunctiva)
RESERVOIR
Human, Wild Animals
RISK FACTORS
- Care for patients (droplet/airborne)
- Travel to endemic area
TREATMENT
Treatment is supportive. [Merck Manual, p. 1690] Pfizer announced on 11/5/2021 that an antiviral pill was 89% effective in high-risk cases of COVID-19. [https://www.bbc.com/news/health-59178291] Also, see "Coronavirus (COVID-19) Update: FDA Authorizes Monoclonal Antibodies for Treatment of COVID-19." [https://www.fda.gov/news-events/press-announcements/coronavirus-covid-19-update-fda-authorizes-monoclonal-antibodies-treatment-covid-19]
REFERENCES FOR CASES/YEAR
1. (US) Coronaviruses are associated with about 15% of common cold cases and 10% of acute respiratory infections. [Cecil, p. 2165] Guesstimate: use cases/yr for "Upper respiratory infections" X 15% = 1.2 billion X 15% = 180 million cases/year;
2. (Global) Outbreak of SARS occurred in 2002-2003 with 8096 cases in 28 countries, (about 90% of cases in China and Hong Kong); [Harrison ID, p. 776] Outbreak of MERS-CoV in 2012 in Saudi Arabia with hundreds of cases; [CDC website] Guesstimate: 20 X US cases/yr = 3.6 billion cases/year;