Viral Hemorrhagic Fevers - Lassa Fever

Question 1

What is Lassa Fever also known as?

Answer 1

Lassa Hemorrhagic Fever (LHF)

LHF is an acute viral hemorrhagic fever.

Question 2

Where is Lassa Fever endemic?

Answer 2

Parts of West Africa
The disease is associated with rodent populations in these regions.

Question 3

When was Lassa Fever first described?

Answer 3

1969
The disease was first identified in the town of Lassa, in Borno State, Nigeria.

Question 4

What virus causes Lassa Fever?

Answer 4

Lassa virus
Lassa virus is a member of the Arenavirus family.

Question 5

What is the primary animal host of the Lassa virus?

Answer 5

Mouse (Mastomys natalensis)
This rodent species is indigenous to most of Sub-Saharan Africa.

Question 6

Lassa Fever is classified as what type of disease?

Answer 6

Acute viral hemorrhagic fever
It is characterized by bleeding and can be life-threatening.

Question 7

True or False: Lassa virus is transmitted primarily through human-to-human contact.

Answer 7

False
The primary transmission is from the animal host (mouse) to humans.

Question 8

Fill in the blank: Lassa Fever is endemic in rodent populations in parts of _______.

Answer 8

West Africa
The disease is closely linked to rodent habitats.

Question 9

How is Lassa viral hemorrhagic fever transmitted to humans?

Answer 9

Through contact with food or household items contaminated with rodent excreta

Rodent excreta is a primary source of the virus for humans.

Question 10

What can facilitate person-to-person transmission of Lassa fever?

Answer 10

Airborne route or direct contact with infected human blood, urine, semen, or vaginal fluids

This highlights the importance of infection control in healthcare settings.

Question 11

Can Lassa fever be transmitted through breast milk?

Answer 11

Yes, transmission through breast milk has been observed

This indicates potential risks for breastfeeding infants from infected mothers.

Question 12

For how long can the Lassa virus remain in urine after infection?

Answer 12

Three to nine weeks

This persistence can contribute to ongoing transmission risks.

Question 13

For how long can the Lassa virus remain in semen after infection?

Answer 13

Up to three months

This extended presence in semen raises concerns for sexual transmission.

Question 14

True or False: Lassa fever can be transmitted in a laboratory environment without adequate infection control measures.

Answer 14

True

Question 15

What is a notable aspect of the Lassa virus after recovery?

Answer 15

It remains in body fluids for long periods of time

This can lead to potential transmission risks even after an individual feels recovered.

Question 16

What percentage of people infected with Lassa fever show mild or no observable symptoms?

Answer 16

Up to 80%

Question 17

What percentage of individuals infected with Lassa fever develop a severe multisystem disease?

Answer 17

20%

Question 18

What is the incubation period of Lassa fever?

Answer 18

7 to 21 days

Question 19

What initial symptoms characterize the clinical disease of Lassa fever?

Answer 19

Flu-like illness characterized by fever, general weakness, and malaise

Question 20

Which additional symptoms may accompany the initial flu-like illness of Lassa fever?

Answer 20

Cough, sore throat, and severe headache

Question 21

What gastrointestinal manifestations are common in Lassa fever?

Answer 21

Nausea, vomiting, and diarrhea

Question 22

Are hemorrhagic manifestations an important feature of Lassa fever?

Answer 22

No

Question 23

What is likely central to Lassa fever-associated pathogenesis?

Answer 23

Disturbance of vascular function

Question 24

What do signs of increased vascular permeability indicate for Lassa fever prognosis?

Answer 24

A poor prognosis

Question 25

In severe cases, What conditions can patients experience related to pulmonary edema?

Answer 25

Severe pulmonary edema with acute respiratory distress

Question 26

In severe cases, What clinical signs may indicate encephalopathy in patients?

Answer 26

Coma, seizures, and terminal shock

Question 27

What is a common symptom associated with Lassa fever?

Answer 27

Bleeding from mucosal surfaces

Question 28

Is the bleeding from mucosal surfaces in Lassa fever typically severe enough to produce shock?

Answer 28

No, it is usually not of a magnitude to produce shock by itself

Question 29

What type of deafness is commonly observed in patients during late stages of disease or early convalescence?

Answer 29

SENSORINEURAL DEAFNESS This condition often occurs in survivors of Lassa fever.

Question 30

List the macroscopic pathological changes associated with Lassa fever.

Answer 30

* Pleural Effusions * Pulmonary Edema * ascites * Hemorrhagic manifestation in the Gastrointestinal Mucosa

Question 31

What microscopic findings are associated with Lassa fever?

Answer 31

* Helatcellular Necrosis * Splenic Necrosis * Adrenocortical Necrosis * Interstitial Myocarditis * Alveolar Edema * Mild Interstitial Pneumonitis * Lymph Nodal Sinus Histiocytosis * Gastrointestinal Mucosal Petechiae * Renal Tubular Injury

Question 32

………. is commonly observed in patients during ……….. of disease or ………. in survivors?

Answer 32

Sensoneuronal deafness late stages early convalescence

Question 33

What is the most common method for diagnosing Lassa fever?

Answer 33

Enzyme-linked immunosorbent serologic assays (ELISA) ELISA detects IgM and IgG antibodies as well as Lassa antigen.

Question 34

Which diagnostic method can be used in the early stage of Lassa fever?

Answer 34

Reverse transcription-polymerase chain reaction (RT-PCR)

Question 35

How long does it take to culture the Lassa virus?

Answer 35

7 to 10 days

Question 36

What technique can be used for post-mortem diagnosis of Lassa fever?

Answer 36

Immunohistochemistry

Question 37

What antiviral drug has been used successfully in Lassa fever treatment?

Answer 37

Ribavirin Ribavirin is most effective when administered early in the illness.

Question 38

Ribavirin is most effective when given _______ in the course of Lassa fever.

Answer 38

early

Question 39

What is the primary focus of supportive care in Lassa fever treatment?

Answer 39

Maintenance of appropriate fluid and electrolyte balance

Question 40

What additional aspects are included in the supportive care for Lassa fever?

Answer 40

Oxygenation and blood pressure management, treatment of any other complicating infections