Lassa Fever

Question 1

Lassa mammarenavirus is a single stranded RNA virus. Do all patients with Lassa infection present with symptoms?

Answer 1

• no

Aprox 80% are asymptomatic

Question 2

What is the incubation period of Lassa fever once infected?

1 - <7 days
2 - 6-21 days
3 - <11 days
4 - <21 days

Answer 2

2 - 6-21 days

Question 3

How is Lassa fever transmitted? (select 2)

1 - exposure to urine or faeces of infected Mastomys rats
2 - consumption of contaminated water
3 - tick bite in south America
4 - direct contact with tbodily fluids (blood, urine, faeces, etc.)

Answer 3

2 - consumption of contaminated water

4 - direct contact with tbodily fluids (blood, urine, faeces, etc.)

Question 4

Lassa fever is common in all of the following, but which of the following is often described as the capital of Lassa fever?

1 - Benin
2 - Ghana
3 - Nigeria
4 - Guinea

Answer 4

3 - Nigeria

Likely to be prevalent throughout West Africa

Question 5

When is the most likely period where an individual may contract lassa fever in Nigeria?

1 - dry season - Jan-Feb
2 - dry season - Jul-Aug
3 - wet season - Jan-Feb
4 - wet season - Jul-Aug

Answer 5

1 - dry season - Jan-Feb

In wet season, the infected urine would most likely be washed away

Question 6

Does Lassa fever affect men or women more?

Answer 6

• affects both equally

All age groups can be affected

Question 7

Which 2 of the following can be used to diagnose Lassa fever?

1 - viral RNA PCR
2 - blood cultures
3 - serologic assays forvirus-specific antibodies (ELISA)
4 - thick and thin blood films

Lassa fever is difficult to distinguish from other viral haemorrhagic fevers such as Ebola virus disease as well as other diseases that cause fever, including malaria, shigellosis, typhoid fever and yellow fever.

Answer 7

1 - viral RNA PCR
3 - serologic assays forvirus-specific antibodies (ELISA)

Ultimately, identifying the specific cause of Lassa fever can be identified in a specialist laboratory

Question 8

Which of the following is NOT an initial presenting symptom of Lassa fever?

1 - fever
2 - malaise and myalgias
3 - bloody diarrhoea
4 - headaches
5 - GIT symptoms (diarrhoea)

Answer 8

3 - bloody diarrhoea

Blood diarrhoea can be caused by Shigella, Salmonella, Campylobacter, Yersinia, and Clostridium spp.

Really hard to distinguish Lassa fever from other causes of fever, such as malaria, shigellosis, typhoid fever and yellow fever

Question 9

As Lassa disease progresses, which of the following can it present with?

1 - low BP
2 - face swelling
3 - nose bleeds/mucosal bleeds
4 - petechia
5 - all of the above

Answer 9

4 - all of the above

Lassa fever is a viral haemorrhagic fever (VHF) which is essentially a fever with internal/external bleeding

Can lead to death

Question 10

Which of the following patients is Lassa disease especially severe in?

1 - <12y/o
2 - 3rd trimester pregnancy
3 - 1st trimester pregnancy
4 - older adults >65

Answer 10

2 - 3rd trimester pregnancy

The disease is especially severe late in pregnancy, with maternal death and/or fetal loss occurring in more than 80% of cases during the third trimester.

Question 11

What is typically the 1st line treatment for Lassa fever?

1 - antibiotics
2 - antivirals
3 - post-exposure
4 - supportive treatment

Answer 11

4 - supportive treatment

Treatment includes:
- fluids
- electrolytes
- blood transfusion
- treatment for shock

Question 12

Although antivirals are rarely used, which of the following is the drug of chose if an antiviral is to be used?

1 - ribavirin
2 - enofovir
3 - raltegravir
4 - any of the above

Answer 12

1 - ribavirin

Given early following infection is best