How does the Lassa virus replicate?
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 fever DNA or RNA?
Though first described in the 1950s, the virus causing Lassa disease was not identified until 1969. The virus is a single-stranded RNA virus belonging to the virus family Arenaviridae. About 80% of people who become infected with Lassa virus have no symptoms.
What shape is Lassa virus?
Lassa virus is spherical in shape and is a medium-sized agent that measures between 70 and 150 nm in diameter (Figure 1). It has been classified into the arenaviridae family. A typical mature Lassa virus particle possesses a glycoprotein envelope with T-shaped spikes measuring 7–10 nm on its surface.
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).
Is Lassa virus enveloped?
Lassa virus is an enveloped virus with glycoprotein spikes on its surface. It contains an RNA ambisense genome that encodes the glycoprotein precursor GP-C, the nucleoprotein NP, the polymerase L, and the Z protein.
What is the pathophysiology of Lassa fever?
Gross Pathology 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.
What is the vector of Lassa fever?
Lassa fever is an animal-borne, or zoonotic, acute viral illness spread by the common African rat. It is endemic in parts of West Africa including Sierra Leone, Liberia, Guinea and Nigeria. Neighboring countries are also at risk because the animal vector lives throughout the region.
Is Lassa virus naked or enveloped?
Lassa virus. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range.
Is Lassa fever virus an RNA virus?
Lassa viruses are enveloped, single-stranded, bisegmented, ambisense RNA viruses. Their genome is contained in two RNA segments that code for two proteins each, one in each sense, for a total of four viral proteins.
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 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.
How did Lassa fever start?
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. The virus, a member of the virus family Arenaviridae, is a single-stranded RNA virus and is zoonotic, or animal-borne.
What type of rat carries 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.
What chemicals make up a virus?
The essential components of infectious viral particles are nucleic acid (the genome) and protein. In addition, all enveloped viruses contain lipid in the envelope and carbohydrate in their glycoprotein peplomers (as well as that in the nucleic acid).
What is an envelope of a virus?
A virus that has an outer wrapping or envelope. This envelope comes from the infected cell, or host, in a process called “budding off.” During the budding process, newly formed virus particles become “enveloped” or wrapped in an outer coat that is made from a small piece of the cell’s plasma membrane.
Is Lassa virus A DNA virus?
Is Lassa fever related to Ebola?
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.
Is Lassa fever a zoonotic disease?
What animal causes Lassa fever?
Is there a cure for Lassa?
Lassa fever causes an approximate 5000 to 10,000 deaths annually in West Africa and cases have been imported into Europe and the Americas, challenging public health. Although Lassa virus was first described over 5 decades ago in 1969, no treatments or vaccines have been approved to treat or prevent infection.
The virus replicates in a wide variety cell types (believed to be primarily dendritic cells) after having entered the cell via its receptor alpha-dystroglycan (DAG1). Interestingly, a gene LARGE that modifies DAG1 and is required for Lassa viral entry was discovered by VHFC researchers to be under positive selection in the West African population.
What is the pathophysiology of Lassa virus?
Lassa virus consists of four lineages, which have a strain variation of 27% in relation to their nucleotides and 15% in relation to their amino acids. The large segment encodes a small zinc-bindingprotein (Z) that regulates transcription and replication and the RNA polymerase (L).
What is the genome of Lassa virus?
Genome of Lassa Virus. It contains two species of RNA called the small and large units and each unit has two genes at opposite ends that do not overlap. The small unit has some double stranded areas that form stem-loop structures.
How does the Lassa virus attach to alpha-dystroglycan?
The Lassa virus has been shown to use the NH2-terminus in its attachment to alpha-dystroglycan. The glycoprotein GP-1 which is used to join the virus and host cell together, is created when the glycosylated precursor protein (GP-C) is cleaved into GP-1 and GP-2.