Lassa fever is a viral hemorrhagic illness transmitted to humans through contact with the urine or feces of infected Mastomys rats. It is endemic in parts of West Africa, with 100,000-300,000 infections estimated annually. Symptoms can include bleeding, abdominal pain, and fever. Treatment involves supportive care and the antiviral ribavirin if given early. Prevention focuses on proper food storage, hygiene practices, and rodent control to avoid exposure to infected rats.

1. LASSA FEVER
Presented by
Ishola-Gbenla Modupe MD
Case Management, GFMalaria.
03/02/2020

2. OUTLINE
• INTRODUCTION
• MODE OF TRANSMISSION
• EPIDEMIOLOGY
• SYMPTOMS
• PREVENTION
• TREATMENT
• QUESTIONS

3. INTRODUCTION
• Lassa fever is an acute, viral, haemorrhagic illness
• Common in the West African region: Nigeria, Guinea,
Sierra Leone.
• The name is derived from a town in Borno State, Nigeria.
• It was first discovered and Isolated in 1969, first case was
in an American Missionary who died in Nigeria.

4. MODE OF TRANSMISSION
Lassa Fever is a zoonotic infection: transmitted by a rat called Matomys
natalensis. It is a multimmamate rat i.e has 12 breasts on each side instead of
the usual 5 or 6.The tail is usually longer than the body.

5. EPIDEMIOLOGY
• 100,000 to 300,000, infections per year in west Africa, with
approximately 5,000 deaths [CDC & WHO]
• Accounts for 10%-16% of people admitted to hospitals every
year in some places [CDC]
• Approximately 15%-20% of patients hospitalized for Lassa
fever die.
• However, only 1% of all Lassa virus infections result in death.
• Death usually occurs within 14 days of onset symptoms onset
in fatal cases
• Affects all age group and both sexes
• Seasonal clustering: late rainy season and early dry season

6. MODE OF TRANSMISSION
• Aerosolization: Transmission by air, inhalation of urine
polluted dust.
• Virus carried by the Mastomys rat, shed in its urine and
droppings
• The virus is transmitted to humans from direct contact with
infected rats by catching, handling and preparing them for
food, or
• Through contact with food or household items contaminated
with rat faeces or urine.
• The virus can also be transmitted through contact with an
infected person’s body fluids.
• Wound exposure from handling infected rodents.

7. SYMPTOMS

8. SYMPTOMS
• 80% of cases are asymptomatic
• Incubation period is 3-21 days
• Bleeding from orifices; nose, mouth, vagina, anus
• Abdominal pain, chest pain and muscle pain.
• Symptoms can mimic Malaria or Typhoid fever (do not
self medicate)

9. PREVENTION
• Avoid buying/eating exposed food from stores/shops
• Safe food storage [Store in containers with lid/cover/seal]
• Wash all fresh fruits/foods properly before eating
• Cook your foods thoroughly
• Regular & proper hand washing and maintain good hygiene
• Avoid contact with blood and body fluids while caring for sick
persons
• Safe burial practices
• Wet down surfaces before sweeping
• Virus is inactivated by heating >56 *C, UV rays(sun)
detergents.

10. PREVENTION
• Disposing of garbage far from the home
• Keep your home clean and tidy to discourage rats from
entering: Make your homes rat-proof
• Keep a cat, chases the rats away
• Find, trap and sanitarily dispose off rats: Involve your
neighbors
• Avoid rodents as food source: DO NOT EAT RATS
• Suspect every case of fever & seek care in a health facility for
proper diagnosis and treatment. Getting medical treatment
early is your best chance at surviving.
• Avoid contacts with other people when you are ill/feverish

13. TREATMENT & PROPHYLAXIS
• Supportive measures
• The antiviral drug ribavirin seems to be an effective
treatment for Lassa fever if given early on in the course
of clinical illness (first 6days)
• There is no evidence to support the role of ribavirin as
post-exposure prophylactic treatment for Lassa fever
• There is currently no vaccine that protects against Lassa
fever. However, research are on-going to find a vaccine