Differentials

Malaria infection

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Most common cause of non-specific febrile illness in returning travellers. [97]

Inadequate or no malaria chemoprophylaxis.

There are no differentiating signs and symptoms.

Co-infection with malaria was seen in up to 5% of patients in West Africa during the 2014 outbreak, so the possibility of dual infection should be considered in all patients. [79]

INVESTIGATIONS

Giemsa-stained thick and thin blood smears: positive for Plasmodium species.

Rapid diagnostic tests: positive for Plasmodium species (note: P ovale is not always detected by some rapid diagnostic tests).

It is recommended that appropriate confirmatory tests for Ebola virus infection are performed before, or in tandem with, differentiating tests if Ebola virus infection is suspected.

Marburg virus infection

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

There are no differentiating signs and symptoms.

Epidemiological features can help differentiate between the viral haemorrhagic fevers (i.e., exposure to bats, caves, or mining). [111]

INVESTIGATIONS

Reverse transcriptase-polymerase chain reaction (RT-PCR): positive for Marburg virus RNA.

It is recommended that appropriate confirmatory tests for Ebola virus infection are performed before, or in tandem with, differentiating tests if Ebola virus infection is suspected.

Crimean-Congo haemorrhagic fever (CCHF)

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

There are no differentiating signs and symptoms.

Epidemiological features can help differentiate between the viral haemorrhagic fevers (i.e., animal butchering, tick bite, or exposure to animals). [112]

INVESTIGATIONS

RT-PCR: positive for CCHF virus RNA.

It is recommended that appropriate confirmatory tests for Ebola virus infection are performed before, or in tandem with, differentiating tests if Ebola virus infection is suspected.

Lassa fever

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

There are no differentiating signs and symptoms.

Epidemiological features can help differentiate between the viral haemorrhagic fevers (i.e., exposure to rats in endemic areas). [113]

INVESTIGATIONS

RT-PCR: positive for Lassa virus RNA.

It is recommended that appropriate confirmatory tests for Ebola virus infection are performed before, or in tandem with, differentiating tests if Ebola virus infection is suspected.

Rift Valley fever

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

There are no differentiating signs and symptoms.

Epidemiological features can help differentiate between the viral haemorrhagic fevers (i.e., mosquito exposure, livestock handling, consuming raw animal fluids/tissues).

INVESTIGATIONS

RT-PCR: positive for Rift Valley fever virus RNA.

It is recommended that appropriate confirmatory tests for Ebola virus infection are performed before, or in tandem with, differentiating tests if Ebola virus infection is suspected.

Yellow fever

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

There are no differentiating signs and symptoms.

Epidemiological features can help differentiate between the viral haemorrhagic fevers (i.e., mosquito exposure, lack of immunisation).

INVESTIGATIONS

RT-PCR: positive for yellow fever virus RNA.

It is recommended that appropriate confirmatory tests for Ebola virus infection are performed before, or in tandem with, differentiating tests if Ebola virus infection is suspected.

Typhoid infection

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

There are no differentiating signs and symptoms.

INVESTIGATIONS

Blood or stool culture: positive for Salmonella enterica .

It is recommended that appropriate confirmatory tests for Ebola virus infection are performed before, or in tandem with, differentiating tests if Ebola virus infection is suspected.

Rickettsial infections

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Includes murine typhus, African tick-bite fever, and epidemic typhus. [114]

Eschar is typical.

Lymphadenopathy may be present.

Discrete rash.

INVESTIGATIONS

Serology: positive for Rickettsia species.

Eschar PCR: positive for Rickettsia species.

It is recommended that appropriate confirmatory tests for Ebola virus infection are performed before, or in tandem with, differentiating tests if Ebola virus infection is suspected.

Dengue fever

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

There are no differentiating signs and symptoms.

INVESTIGATIONS

Serology: positive IgM or IgG.

Non-structural protein (NS1) detection: positive.

Reverse transcriptase-polymerase chain reaction (RT-PCR): positive.

It is recommended that appropriate confirmatory tests for Ebola virus infection are performed before, or in tandem with, differentiating tests if Ebola virus infection is suspected.

Measles infection

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Unvaccinated.

There are no differentiating signs and symptoms in prodromal phase.

Koplik's spots (red spots with bluish-white central dot) on buccal mucosa.

Rash typically starts on face and spreads craniocaudally.

INVESTIGATIONS

Serology: positive for measles virus.

It is recommended that appropriate confirmatory tests for Ebola virus infection are performed before, or in tandem with, differentiating tests if Ebola virus infection is suspected.

Leptospirosis

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

There are no differentiating signs and symptoms; however, a history of exposure may be helpful.

Exposure to contaminated water or soil contaminated by infected rodents. [115]

More common in tropical climates.

INVESTIGATIONS

PCR: positive.

Serology: positive.

It is recommended that appropriate confirmatory tests for Ebola virus infection are performed before, or in tandem with, differentiating tests if Ebola virus infection is suspected.

Seasonal influenza infection

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Respiratory signs and symptoms (e.g., cough, nasal congestion) are more common.

INVESTIGATIONS

Viral culture or PCR: detection of seasonal influenza virus or viral RNA.

FBC: normal.

It is recommended that appropriate confirmatory tests for Ebola virus infection are performed before, or in tandem with, differentiating tests if Ebola virus infection is suspected.

Gastroenteritis

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

In the correct epidemiological context, this can present in a similar way to Ebola virus infection. However, features such as rash, conjunctival injection, and prostration are very rare in gastroenteritis.

INVESTIGATIONS

Stool culture, PCR, or rapid antigen testing: positive.

It is recommended that appropriate confirmatory tests for Ebola virus infection are performed before, or in tandem with, differentiating tests if Ebola virus infection is suspected.

Sepsis

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Bacterial sepsis with an unclear origin is a common presentation in developing countries. Often turns out to be deep abdominal infection, upper urinary tract infection, endocarditis, or discitis.

Diarrhoea is often absent.

INVESTIGATIONS

Blood cultures: positive.

It is recommended that appropriate confirmatory tests for Ebola virus infection are performed before, or in tandem with, differentiating tests if Ebola virus infection is suspected.

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