Differentials

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Residence in/travel to a country/area or territory with local transmission, or close contact with a confirmed or probable case of COVID-19, in the 14 days prior to symptom onset. 

Signs and symptoms are similar so it may be difficult to differentiate between the conditions clinically.

The situation is evolving rapidly; see our COVID-19 topic for further information.

INVESTIGATIONS

Real-time reverse transcription polymerase chain reaction (RT-PCR): positive for SARS-CoV-2 RNA.

It is not possible to differentiate COVID-19 from other causes of pneumonia on chest imaging.

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Lack of travel history to or from the Middle East (or country where there is an ongoing outbreak) in the preceding 14 days.

No close contact with a symptomatic traveller from the Middle East or a suspected or confirmed case of MERS in the preceding 14 days.

Patients have lower incidence of comorbidities compared with MERS.

Clinical features are similar; however, patients are less likely to present with haemoptysis (1% of patients with SARS) or dyspnoea (42% of patients with SARS).[8]

Usually less aggressive than MERS as reflected by the lower mortality rate.[113]

INVESTIGATIONS

RT-PCR: positive for SARS-CoV RNA.[96][114]

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Lack of travel history to or from the Middle East (or country where there is an ongoing outbreak) in the preceding 14 days.

No close contact with a symptomatic traveller from the Middle East or a suspected or confirmed case of MERS in the preceding 14 days.

Seasonal outbreak during winter.

Differentiating MERS from community-acquired respiratory tract infections is not possible from signs and symptoms.

INVESTIGATIONS

RT-PCR: negative for MERS coronavirus (MERS-CoV) RNA.

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Lack of travel history to or from the Middle East (or country where there is an ongoing outbreak) in the preceding 14 days.

No close contact with a symptomatic traveller from the Middle East or a suspected or confirmed case of MERS in the preceding 14 days.

Seasonal outbreak during winter.

Differentiating MERS from community-acquired respiratory tract infections is not possible from signs and symptoms.

INVESTIGATIONS

RT-PCR: positive for influenza A or B viral RNA.

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Lack of travel history to or from the Middle East (or country where there is an ongoing outbreak) in the preceding 14 days.

No close contact with a symptomatic traveller from the Middle East or a suspected or confirmed case of MERS in the preceding 14 days.

Close contact with infected birds (e.g., farmer or visitor to a live market in endemic areas) or living in an area where avian influenza is endemic.

Differentiating MERS from community-acquired respiratory tract infections is not possible from signs and symptoms.

INVESTIGATIONS

RT-PCR: positive for H5N1 viral RNA.

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Lack of travel history to or from the Middle East (or country where there is an ongoing outbreak) in the preceding 14 days.

No close contact with a symptomatic traveller from the Middle East or a suspected or confirmed case of MERS in the preceding 14 days.

Close contact with infected birds (e.g., farmer or visitor to a live market in endemic areas) or living in an area where avian influenza is endemic. Up until now, the epidemic has been geographically focused in China.

Differentiating MERS from community-acquired respiratory tract infections is not possible from signs and symptoms.

INVESTIGATIONS

RT-PCR: positive for H7-specific viral RNA.

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Lack of travel history to or from the Middle East (or country where there is an ongoing outbreak) in the preceding 14 days.

No close contact with a symptomatic traveller from the Middle East or a suspected or confirmed case of MERS in the preceding 14 days.

Common cause of lower respiratory tract infection in children <1 year of age.

Seasonal outbreak during winter.

Differentiating MERS from community-acquired respiratory tract infections is not possible from signs and symptoms.

INVESTIGATIONS

RT-PCR: positive for RSV RNA.

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Lack of travel history to or from the Middle East (or country where there is an ongoing outbreak) in the preceding 14 days.

No close contact with a symptomatic traveller from the Middle East or a suspected or confirmed case of MERS in the preceding 14 days.

Differentiating MERS from community-acquired respiratory tract infections is not possible from signs and symptoms.

INVESTIGATIONS

Blood or sputum culture, or multiplex RT-PCR testing: positive for causative organism (e.g., Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, Chlamydophila pneumoniae, Moraxella catarrhalis).

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Lack of travel history to or from the Middle East (or country where there is an ongoing outbreak) in the preceding 14 days.

No close contact with a symptomatic traveller from the Middle East or a suspected or confirmed case of MERS in the preceding 14 days.

Differentiating MERS from community-acquired respiratory tract infections is not possible from signs and symptoms.

Unlikely to cause serious illness in young, healthy patients.

INVESTIGATIONS

Nasopharyngeal virus culture or RT-PCR: positive for causative organism (e.g., parainfluenza viruses, adenoviruses, rhinoviruses, enteroviruses, human metapneumovirus) or viral RNA.

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