How does Lassa virus reproduce?
The virus replicates through a strategy known as the Ambisense, where two RNA strands code for genes in both the sense and antisense direction that is rapid and demonstrate temporal control in replication.
Is Lassa virus DNA or RNA?
Lassa virus is a segmented negative-strand RNA virus of the family Arenaviridae causing hemorrhagic fever in humans. The genome consists of two single-stranded RNA segments, each containing two genes in opposite directions (1). The S RNA segment encodes the nucleoprotein (NP) and the glycoprotein precursor.
What is the morphology of Lassa fever?
The Lassa virus particle is round, oval, or pleomorphic, 110 to 130 nm in diameter, and enveloped. Its genome consists of two single-stranded RNA segment – the large L segment and the small S segment.
How does Lassa virus enter cells?
Upon receptor binding, LASV enters the host cell via receptor-mediated endocytosis, with subsequent transport to late endosomal compartments, where fusion occurs at low pH (3, 4).
What is the pathogenesis of Lassa fever?
Cellular Pathogenesis
Following transmission, Lassa virus primarily infects the endothelial cells. The Lassa virus gains entry into the host cell by means of the cell-surface receptor the alpha-dystroglycan (alpha-DG), a versatile receptor for proteins of the extracellular matrix.
What is the vector of Lassa fever?
Lassa fever is endemic in parts of west Africa including Sierra Leone, Liberia, Guinea and Nigeria; however, other neighboring countries are also at risk, as the animal vector for Lassa virus, the “multimammate rat” (Mastomys natalensis) is distributed throughout the region.
What cells does Lassa virus infect?
Antigen-presenting cells (APC)—dendritic cells (DC) and macrophages (MP)—are probably the first cells targeted by LASV [20,21]. The widespread distribution of these cells in the mucosal tissues and skin, results in their early infection, allowing the first replicative cycles to occur.
What is the vector for Lassa fever virus?
Lassa fever is an animal-borne, or zoonotic, acute viral illness spread by the common African rat.
What is the pathophysiology of Lassa fever?
Lassa virus commonly involves the liver and results in hepatocellular necrosis and apoptosis. Other organs may be involved, and Lassa fever infection may manifest with the following: Splenic necrosis. Adrenocortical necrosis.
Where is Lassa fever endemic?
Epidemiology. Lassa fever is endemic in parts of West Africa, particularly Guinea, Liberia, Nigeria and Sierra Leone, where the animal reservoir, the multimammate rat is prevalent.
What is the incubation period of Lassa fever?
The incubation period of Lassa fever ranges from 6–21 days. The onset of the disease, when it is symptomatic, is usually gradual, starting with fever, general weakness, and malaise. After a few days, headache, sore throat, muscle pain, chest pain, nausea, vomiting, diarrhoea, cough, and abdominal pain may follow.
Where does Lassa fever originated from?
Lassa fever is an acute viral illness that occurs in west Africa. The illness was discovered in 1969 when two missionary nurses died in Nigeria. The virus is named after the town in Nigeria where the first cases occurred.
What organs does Lassa fever affect?
About 80% of people who become infected with Lassa virus have no symptoms. 1 in 5 infections result in severe disease, where the virus affects several organs such as the liver, spleen and kidneys. Lassa fever is a zoonotic disease, meaning that humans become infected from contact with infected animals.
What is the difference between Ebola and Lassa fever?
Lassa fever is different from Ebola, the disease that is responsible for the current outbreak in West Africa. Although Lassa fever and Ebola can result in similar symptoms, Lassa fever is less likely than Ebola to spread from person to person and is far less deadly.
What causes bleeding in Lassa fever?
Lassa fever is an acute, viral disease carried by a type of rat that is common in West Africa. It can be life-threatening. It is a hemorrhagic virus, which means it can cause bleeding, although 8 out of every 10 people with the virus have no symptoms. If it affects the liver, kidneys, or spleen, it can be fatal.
What is the scientific name for Lassa fever?
Lassa mammarenavirus (Lassavirus) is a vector-borne virus consisting of bipartite single-stranded, ambisense RNA genomes. It is a member of the Arenaviridae family (genus= Mammarenavirus) and infects rodents and humans. Lassavirus is named for Lassa village in Nigeria where two nurses became infected in 1969.
Who is most affected by Lassa fever?
Lassa fever is known to be endemic in Benin, Ghana, Guinea, Liberia, Mali, Sierra Leone, and Nigeria, but probably exists in other West African countries as well. The overall case-fatality rate is 1%. Observed case-fatality rate among patients hospitalized with severe cases of Lassa fever is 15%.
Who is most at risk for Lassa fever?
Individuals at greatest risk of Lassa virus infection are those who live in or visit endemic regions, including Sierra Leone, Liberia, Guinea, and Nigeria and have exposure to the multimammate rat. Risk of exposure may also exist in other west African countries where Mastomys rodents exist.
What is the first symptom of Lassa fever?
The signs and symptoms of Lassa Fever is usually gradual. It starts with fever general weakness, and malaise. After a few days, headache, sore throat, muscle pain, chest pain, nausea, vomiting, diarrhoea, cough, and abdominal pain may follow.
What are the complications of Lassa fever?
The most common complication of Lassa fever is deafness. Various degrees of deafness occur in approximately one-third of infections, and in many cases hearing loss is permanent. As far as is known, severity of the disease does not affect this complication: deafness may develop in mild as well as in severe cases.
What is the name of the rat that causes Lassa fever?
The reservoir, or host, of Lassa virus is a rodent known as the “multimammate rat” (Mastomys natalensis). Once infected, this rodent is able to excrete virus in urine for an extended time period, maybe for the rest of its life.
How does Lassa fever affect the liver?
Patients with severe Lassa fever have high serum levels of liver enzymes. Studies of the histology of the liver have shown only minor alterations, seemingly insufficient to account for death.
What does Lassa fever do to the body?
What are the early signs of Lassa fever?
Symptoms of Lassa fever
The onset of the disease, when it is symptomatic, is usually gradual, starting with fever, general weakness, and malaise. After a few days, headache, sore throat, muscle pain, chest pain, nausea, vomiting, diarrhoea, cough, and abdominal pain may follow.
How is Lassa fever transmitted from person to person?
Transmission of Lassa virus to humans occurs most commonly through ingestion or inhalation. Mastomys rodents shed the virus in urine and droppings and direct contact with these materials, through touching soiled objects, eating contaminated food, or exposure to open cuts or sores, can lead to infection.