|
|
| (84 intermediate revisions by 3 users not shown) |
| Line 1: |
Line 1: |
| __NOTOC__
| | #redirect [[Lassa virus]] |
| {{Lassa fever}}
| |
| {{CMG}}
| |
| | |
| ==Overview==
| |
| Lassa fever is caused by the ''Lassa virus'', a member of the [[Arenaviridae]] family; it is an [[enveloped virus|enveloped]], single-stranded, bisegmented [[RNA]] virus. [[viral replication|Replication]] for Lassa virus is very rapid, while also demonstrating temporal control in replication. There are two [[genome]] segments. The first step involved is making [[messenger RNA|mRNA]] copies of the negative-sense [[genome]]. This ensures that there are adequate [[protein]]s, which are required for [[replication]]. The N and L proteins are made from the mRNA produced. The -ve sense genome then makes vcRNA (viral circular RNA) copies of itself which are positive-sense. The vcRNA is a [[template strand|template]] for producing -ve sense progeny but mRNA is also synthesized from it. The mRNA synthesized from vcRNA [[translation (biology)|translates]] the [[G proteins|G (spike) proteins]] and Z proteins. Thus, with this temporal control, the spike proteins are produced last, making the infection further undetected by the [[host (biology)|host]] [[immune system]].
| |
| ==Vector==
| |
| * 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. Mastomys rodents breed frequently, produce large numbers of offspring, and are numerous in the savannas and forests of west, central, and east Africa. In addition, Mastomys readily colonize human homes and areas where food is stored. All of these factors contribute to the relatively efficient spread of Lassa virus from infected rodents to humans.
| |
| * Transmission of Lassa virus to humans occurs most commonly through [[ingestion]] or [[inhalation]]. Mastomysrodents 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]].
| |
| * Because Mastomys rodents often live in and around homes and scavenge on leftover human food items or poorly stored food, direct contact transmission is common. Mastomys rodents are sometimes consumed as a food source and infection may occur when rodents are caught and prepared. Contact with the [[virus]] may also occur when a person inhales tiny particles in the air contaminated with infected rodent excretions. This aerosol or airborne transmission may occur during cleaning activities, such as sweeping.
| |
| * Direct contact with infected rodents is not the only way in which people are infected; person-to-person transmission may occur after exposure to [[virus]] in the [[blood]], [[tissue]], secretions, or excretions of a Lassa virus-infected individual. Casual contact (including [[skin]]-to-[[skin]] contact without exchange of [[body fluids]]) does not spread Lassa virus. Person-to-person transmission is common in health care settings (called [[nosocomial transmission]]) where proper personal protective equipment (PPE) is not available or not used. Lassa virus may be spread in contaminated medical equipment, such as reused needles.
| |
| ==References==
| |
| {{Reflist|2}}
| |
| | |
| [[Category:Disease]]
| |
| [[Category:Viral diseases]]
| |
| [[Category:Viruses]]
| |
| [[Category:Zoonoses]]
| |
| [[Category:Hemorrhagic fevers]]
| |
| [[Category:Tropical disease]]
| |
| [[Category:Biological weapons]]
| |
| [[Category:Infectious disease]]
| |
| [[Category:Needs content]]
| |
| | |
| {{WikiDoc Help Menu}}
| |
| {{WikiDoc Sources}}
| |