The nigeria centre for disease control ncdc has said that these statistics should not mask the progress made in the control of lassa fever in the worlds worst hit country. The animal reservoir, or host, of lassa virus is a rodent of the genus mastomys, commonly known as the multimammate rat. The incubation period for lassa fever varies from 6 21 days. The virus is spread by a rat that lives in large numbers in west, central, and east africa.
Lassa virus infection occurs through contact with the vector mastomys natalensis or infected humans and can lead to wide symptoms from a mild. According to authority, the deadly virus has reached more than 10 out of the 18 local government areas of the state. A historical look at the first reported cases of lassa fever. Lassa virus entry requires a triggerinduced receptor switch. Lassa fever is an acute viral illness that occurs in west africa.
Lassa fever lf is a zoonotic disease associated with acute and potentially fatal hemorrhagic illness caused by lassa virus lasv, a member of. The virus is endemic in west african countries, which may be due to its zoonotic nature. Lassa antibody and antigen were found in 96 11% and 46 5%, respectively, of 884 tested mastomys demby et al. Secondary human to human spread within a community may occur through inhalation or ingestion. People can get lassa fever through people with lassa fever are not believed to be contagious. The disease was first described in nigeria in 1969. It is most common in a large region of west africa, and is named after the nigerian town where it was.
Lassa fever, on the other hand is caused by the lassa virus. That still counts for some five thousand deaths per year, and lassa fever should by no means be underestimated. In succeeding years, lassa fever was shown to be a prevalent zoonotic disease in west africa, with an estimated 100,000300,000 cases. Lassa fever lf is a febrile infectious disease caused by lassa virus. It is transmitted to humans from contacts with food or household items contaminated with rodent excreta. Another ways the virus spreads is when healthy humans come in contact with the bodily secretions or fluids of someone infected with lassa fever. Laboratory diagnosis of lassa fever journal of clinical. Lassa virus is a linear, bisegmented, singlestranded rna virus, which belong to the arenaviridae family that causes viral hemorrhagic fever transmitted by rats. Health workers may be infected by direct contact with blood, body fluids, urine, or stool of a patient with lassa fever. Jun 27, 2018 lassa fever is a viral hemorrhagic disease. Lassa virus may also be spread between humans through direct contact with the blood, urine, faeces, or other bodily secretions of a person infected with lassa fever.
The lassa fever virus lfv was named after the town where the first cases occurred. Due to the high incidence rate of lassa fever, it has become a major problem in africa. Due to a high fatality rate, lack of treatment options and difficulties with prevention and control, lasv is one of the. The virus is a singlestranded rna virus belonging to the virus family arenaviridae about 80% of people who become infected with lassa virus have no symptoms. Lassa fever is an animalborne, or zoonotic, acute viral illness. The virus can spread between people through direct contact with the body fluids of a person infected with lassa fever or contaminated bedding and clothing. However, health workers are usually infected by direct contact with the blood, body fluids, urine, or stool of a patient who has lassa fever. Feb 06, 20 lassa fever lf is an acute and sometimes severe viral hemorrhagic illness endemic in west africa. Jan 05, 2020 lassa virus is a singlestranded rna virus that is enveloped in lipid with glycoprotein spikes protruding from the outside surface. General facts viral hemorrhagic fever caused by the arenavirus lassa transmitted from rodents to humans discovered in nigeria, 1969 endemic in portions of west africa seasonal clustering. Symptoms can be mild or severe, including hemorrhaging in. Lassa virus remains an important cause of illness in west africa and among the travelers returning from this region with an acute febrile illness.
Lassa fever belongs to a group of viral hemorrhagic fevers and is also termed as lassa hemorrhagic fever lhf. Though a rodentborne infection, it can also be transmitted from person to person during the care of sick relations or more commonly in health care settings as a nosocomial infection. Lassa fever, also known as lassa hemorrhagic fever lhf, is a type of viral hemorrhagic fever caused by the lassa virus. The animal reservoir is the rodent multimammate rat mastomys natalensis. How to diagnose lassa fever lassa virus can be diagnosed in three ways. Lassa fever was first discovered in nigeria, when two missionary nurses became ill with the. The disease is mainly spread to humans through contamination with the urine or feces of infected rats 3,4.
Lassa fever, an acute viral hemorrhagic illness, is endemic in most of west africa, especially nigeria, where it was discovered in 1969. Mar 20, 2018 lassa fever lf is a zoonotic disease associated with acute and potentially fatal hemorrhagic illness caused by lassa virus lasv, a member of the arenaviridae family. Lassa virus infection in experimentally infected marmosets. Lassa fever is endemic in regions of west africa, including guinea, liberia, nigeria, and sierra leone, but cases have been exported to other countries by infected travelers. Symptoms of lassa fever typically occur 221 days after coming into contact with the virus. Lassa fever is a viral infection found in east africa, including sierra leone, liberia, guinea, and nigeria. Lassa fever is an acute viral haemorrhagic illness caused by lassa virus, a member of the arenavirus family of viruses. Lassa fever lf is an acute and sometimes severe viral hemorrhagic illness endemic in west africa. Lassa fever was first discovered in nigeria, when two missionary nurses became ill with the virus in 1969.
It is symptomatic and usually characterized by fever, myalgia, nausea, vomiting, sore throat, abdominal and chest pains. Demonstrating the presence of immunoglobuline m igm antibody to lassa virus. Isolating the virus from blood, urine, or throat washings. There is no epidemiological evidence supporting airborne spread between humans. The disease is endemic in the rodent population in parts of west africa. For example, emmerich and colleagues evaluated the antilassa virus antibody response in a human sample set from west africa by immuno. Lassa fever was first recognized in lassa, nigeria, in 1969 and is endemic to west africa. Lassa mammarenavirus is an emerging virus and a select agent, requiring biosafety level 4equivalent containment. It is spread by contact with infected rodents feces or urine. A historical look at the first reported cases of lassa. Lassa fever is a viral haemorrhagic fever caused by lassa virus belonging to arenaviridae family and is endemic in west african countries of sierra leone, liberia, guinea and nigeria.
Viral hemorrhagic fevers lassa, marburg, ebola, crimean. Lassa virus causes thousands of deaths annually in western africa and is considered a potential biological weapon. In an attempt to develop a small nonhuman primate model of lassa fever, common marmosets were subcutaneously inoculated with lassa virus strain josiah. Persontoperson infections and laboratory transmission can also occur, particularly in the. They carry the virus in their urine and droppings and live in homes and areas where food is stored. Lassa virus, an arenavirus first isolated in 1969 in jos, nigeria, is the cause of lassa fever, an acute viral illness that affects 100,000 to 300,000 persons per year based on 1970s estimates. Current research for a vaccine against lassa hemorrhagic. Infection can also occur after exposure to virus in the blood, tissue, secretions and excretions of a lassa virus infected individuals. Lasv infection of humans can cause lassa fever lf, a disease associated with high.
Jun 27, 2014 lassa virus, which spreads from rodents to humans, infecting about half a million people every year, can lead to deadly hemorrhagic fever. Like many viruses, lassa virus binds to cell surface receptors. Lassa and crimeancongo hemorrhagic fever viruses, mali. Lassa fever outbreak hits nigeria infectioncontrol. Record shows that lassa fever virus is transmitted by rodents, which can be found in the environment meanwhile, the kaduna state government has confirmed a case of lassa fever at chikun local government area of the state. These emerging viral hemorrhagic fevers are presumed to be animal borne zoonotic and can be transmitted to humans through contact. Lassa virus, which spreads from rodents to humans, infecting about half a million people every year, can lead to deadly hemorrhagic fever. Lassa fever was first described in the 1950s, and the viral particle was identified in 1969 from three missionary nurses who died in lassa, nigeria, after caring for an infected obstetrical patient. Vertical transmission from mother to child has been. Lassa virus is zoonotic and infected rodents in the mastomysnatalensis species complex are reservoirs capable of excreting the virus through urine, saliva, excreta and other body fluids to man 7, 11. Less commonly there may be bleeding from the mouth or gastrointestinal tract.
As of march 3, nigeria has confirmed 420 cases of lassa fever and 93 deaths in 2019, suggesting the 2018 record of the most cases reported in a single year will be surpassed. The illness was discovered in 1969 when two missionary nurses died of it in nigeria. Lasv is endemic to west africa and is transmitted through contact with excretions of infected mastomys natalensis rodents and other rodent species. Feb 07, 2020 lassa fever is a viral infection that causes signs and symptoms that include fever, malaise, headache, and weakness. A small percentage of people infected with lassa fever will develop complications like hemorrhaging, respiratory distress, tremors, encephalitis, and multiorgan failure. The lassa fever virus spreads by an animal reservoir, or host, known as the multimammate rat mastomys natalensis. The symptoms of lassa fever can be nonspecific and mimic those of other endemic infections, especially early in illness, making a clinical diagnosis difficult. Lassa mammarenavirus lasv is an arenavirus that causes lassa hemorrhagic fever, a type of viral hemorrhagic fever vhf, in humans and other primates. Lassa fever was first identified in 1969, amongst nurses at a missionary hospital in lassa, nigeria, and the causative virus, lassa virus, was isolated from the blood of affected individuals. Aug 23, 2018 lassa fever is a viral hemorrhagic fever caused by an rna virus of the arenavirus family. Apr 20, 2016 it is caused by the lassa fever virus, a single stranded rna virus belonging to the arenaviridae family 7, 8. Lassa virus entry requires a triggerinduced receptor.
The multimammate mouse mastomys natalensis is the only known nonhuman host for lassa virus monath et al. The illness was discovered in lassa, borno state where it was first reported. An infected person can spread lassa to others via their blood, urine and other bodily fluids. Neighboring countries are also at risk, as the animal vector for lassa virus, the multimammate rat mastomys natalensis is distributed throughout the region. Less commonly there may be bleeding from the mouth or. Difference between ebola and lassa fever ebola vs lassa. Jul 31, 2017 lassa fever is a zoonotic disease, meaning that humans become infected from contact with infected animals. Late rainy and early dry season affects all age groups and both sexes 3. Lassa fever spreads to humans most often through ingestion or inhalation of virus particles in rat urine. Most of the victims of the disease were said to have been quarantined at the federal medical centre, fmc owo. Lassa virus is a singlestranded rna virus that is enveloped in lipid with glycoprotein spikes protruding from the outside surface. Lassa virus is one of more than 25 causative viruses of viral hemorrhagic fever table 4.
Epidemiologic and clinical features of lassa fever. Lassa virus is diagnosed by doing a laboratory test in a test centre. Lassa virus, the causative agent of lassa fever, is a member of the family arenaviridae. Lassa virus diversity and feasibility for universal. National guidelines for lassa fever case management nigeria centre for disease control fever. Many patients usually do not experience any symptoms and if they do develop them, they include weakness, fever, headaches, muscle pains and vomiting. When symptoms occur they typically include fever, weakness, headaches, vomiting, and muscle pains. Lassa fever is a viral illness that typically occurs in west africa. Rodents, particularly mastomys natalensis, are considered the natural hosts of the virus. Baseline mapping of lassa fever virology, epidemiology and. Mar 28, 2019 while often compared to the ebola virus because of overlaps in outbreak zones, lassa fever is less readily communicable and has a far smaller fatality rate about one percent of infected persons, compared to 70% for ebola. The disease is mainly spread to humans through contamination with the urine or feces of infected. Additionally, contact with infected bodily fluids, including blood, urine, and vomit, has been known to spread the virus.
Epidemiologic and clinical features of lassa fever outbreak. Mar 15, 2018 an infected person can spread lassa to others via their blood, urine and other bodily fluids. The first case of lassa fever globally was identified in lassa, a settlement in borno state, north east nigeria in 1969 6, 7. You cannot get lassa fever through hugging, shaking hands or sitting near someone. Lassa fever spread to 11 states, 195 infected, 29 dead ncdc. Sexual partner of a known or suspected case virus can be present in semen for up to 3 months after clinical recovery.
Ribavirin, an antiviral drug, has been used to successfully treat patients with lassa fever. This guideline provides details on how to identify a suspected case of lassa fever, clinical and laboratory diagnosis, clinical management of lassa fever cases including in special. The risk of getting lassa fever in the united states is extremely low signs and symptoms of lassa fever are usually mild lassa fever can be treated if a healthcare worker suspects lassa fever in a patient, a laboratory test can diagnose the disease. It contains two species of rna called the small and large units and each unit has two. Infected humans can spread the virus to each other through contact with contaminated objects or blood. While often compared to the ebola virus because of overlaps in outbreak zones, lassa fever is less readily communicable and has a far smaller fatality rate about one percent of infected persons, compared to 70% for ebola. Deadly lassafever outbreak tests nigerias revamped. This requirement sheds light on the enigmatic resistance of bird cells. The virus is spread by contact with excretions or materials contaminated with the excretions of an infected rodent or inhalation of contaminated dust and bite wounds. Mastomys rats infected with lassa virus do not become ill, but they can shed the virus in their urine and faeces. Current research for a vaccine against lassa hemorrhagic fever virus bryce m warner,1 david safronetz,2 derek r stein2 1department of medical microbiology, university of manitoba, winnipeg, mb, canada.
What is lassa fever, know its causes, symptoms, treatment. Lassa fever is transmitted to humans through contact with the urine or faeces of mastomys rats. Progress and challenges of lassa fever control in nigeria. Lassa fever causes, symptoms, treatment, diagnosis and. Lassa fever is an acute viral haemorrhagic illness that typically occurs in west africa. It is caused by the lassa fever virus, a single stranded rna virus belonging to the arenaviridae family 7, 8. Lassa fever is one of the hemorrhagic fever viruses, occurring in west africa subregions in similar areas as ebola virus. Lassa virus is typically spread through aerosolized virus particles, via either infected rodents mastomys natalensis or close contact with infected individuals.
Lassa fever is a hemorrhagic illness caused by lassa virus. Other ways the virus can spread are through the use of contaminated. It is usually transmitted by the mastomys natalensis multimammate rat. Many of those infected by the virus do not develop symptoms. It can be said that ebola is more dangerous as it has a higher risk of fatality, however it is more rare than lassa fever, which affects up to 500,000 people annually, with a death toll of about 5000. Lassa fever is spread through direct contact with the urine and droppings of the mastomys natalensis, or multimammate rat, as well as through contact with the blood, tissue or secretions of a person infected with the lassa fever virus. It is endemic in west african countries, especially sierra leone, the republic of guinea, nigeria, and liberia, where the annual. The lassa virus is transmitted to humans mainly through handling rats, food or household items. Lassa virus lasv is a highly prevalent mammarenavirus in west africa and is maintained in nature in a persistently infected rodent host, mastomys natalensis, which is widely spread in subsaharan africa. Lassa fever virus is one of the haemorrhagic viruses like ebola virus, marburg virus, and others.
Lassa fever outbreak leaves 43 dead in nigeria cnn. Symptoms of the disease include fever and in some cases, internal bleeding that can lead to death. Glycoproteins on the surface of the virion form tshaped spikes extending 710 nm from the envelope. The commissioner for health, dr amina mohammedbaloni, on saturday said a 36yearold male patient was receiving treatment at a designated infectious disease control. Poor infection prevention and control measures in healthcare settings have also been identified as risk.
Deadly lassafever outbreak tests nigerias revamped health. Though first described in the 1950s, the virus causing lassa disease was not identified until 1969. Lassa fever is caused by infection with the lassa virus. The occurrence of persontoperson transmission via close contact with infected blood, body. Lassa fever is one of the hemorrhagic fever viruses like ebola virus, marburg virus, and others unlike ebola virus, lassa fever is not as contagious person to person, nor as deadly lassa virus is typically transmitted by the urine or feces of mastomys rats to humans. Lassa fever virus lasv causes acute viral haemorrhagic fever with symptoms similar to those seen with ebola virus infections. It is endemic in parts of west africa including sierra leone, liberia, guinea and nigeria.
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