Jan 01, 2019 travellers from areas where lassa fever is endemic can export the disease to other countries, although this rarely occurs. Laboratory diagnosis of lassa fever journal of clinical. The illness was discovered in 1969 when two missionary nurses died in nigeria, west africa. Abstract lassa fever is a viral hemorrhagic fever caused by lassa virus lassa mammarenavirus, a negativesense singlestranded rna virus of the arenaviridae family. Lassa fever is a viral infection that causes signs and symptoms that include fever, malaise, headache, and weakness. However, at the time her laboratory confirmatory test for lassa fever returned, her symptoms had markedly resolved. In this article, we report an analysis of the epidemiologic and clinical aspects of the lf outbreak that occurred in nigeria during january 1may 6, 2018. Lassa fever virus infections approximately 80%, symptoms are mild and are undiagnosed. But in its early presentation, it is very similar to influenza, malaria, shigellosis, typhoid fever, and yellow fever. The cause of the illness was found to be lassa virus, named after the town in nigeria where the first cases originated. Constraints in the diagnosis and treatment of lassa fever and the. Feb 07, 2020 lassa fever is a viral infection that causes signs and symptoms that include fever, malaise, headache, and weakness.
There is usually an incubation period of about 221 days. Lassa fever is an animalborne, or zoonotic, acute viral illness. 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. Symptoms include fever and damage to multiple organs and the circulatory system. Lassa fever is a fatal virus also known as lassa hemorrhagic fever lhf. Apr 20, 2016 lassa fever, an acute viral haemorrhagic fever, extremely virulent and often infectious, occurs very frequently in different parts of nigeria 14 and affects approximately 100,000500,000 persons per year in west africa 5, 6.
Lassa fever, on the other hand is caused by the lassa virus. Lassa fever, an endemic zoonotic viral infection in west africa, presents with varied symptoms including fever, vomiting, retrosternal pain, abdominal pain. Aug 23, 2018 lassa fever is a viral hemorrhagic fever caused by an rna virus of the arenavirus family. The lassa virus is transmitted to humans mainly through handling rats, food or house. Causes lassa fever the main cause of lassa virus is a rodent known as the multimammate rat of the genus mastomys but it is not sure that which species of mastomys are associated with lassa fever. Knowledge, attitude and infection prevention and control practices regarding lassa fever among healthcare workers in edo state, nigeria article pdf available. Infection with lassa virus in humans may take many forms. Lassa fever is also associated with occasional epidemics, during which the casefatality rate can reach 50% in hospitalized patients. In some people, the disease may cause more serious symptoms like bleeding. Symptoms of lassa fever typically occur 221 days after coming into contact with the virus. Two instances ofrelapse of fever and symptoms have beenreported 2, 3. Lassa fever is also associated with occasional epidemics, during which the casefatality rate can reach 50%.
Of the cases reported so far in the nigerian outbreak, the mortality rate is 43. Mar 25, 2014 signs and symptoms of lassa fever typically occur weeks after the patient comes into contact with the virus. Lassa virus lasv, the causative agent of lassa fever, is estimated to be responsible for up to 300,000 new infections and 5000 deaths each year across western africa. Only an estimated 1% of all lassa fever cases result in death. Pdf knowledge, attitude and infection prevention and. Clinically, the disease can resemble other viral hemorrhagic fevers, including the ebola virus, malaria, and typhoid. The world report by talha burki feb 24, p 7281 described an unprecedented astronomical rise in lassa fever cases in nigeria, for which the first case was reported in 1969 and the epidemiology and endemicity are well understood. The incubation period of lassa fever ranges from 621 days. For many lassa fever virus attacks approximately 80%, symptoms are mild and are also undiagnosed. Signs and symptoms of lassa fever typically occur weeks after the patient comes into contact with the virus. Avoid direct contact with rats if rat eat your grain or other food the virus could transfer to the food. In other words, the signs and symptoms of the disease start about one to three weeks after infection with the lassa virus. Ebola and lassa fever are both types of viral hemorrhagic fever caused by different viruses.
The onset of the disease, when it is symptomatic, is usually gradual, starting with fever, general weakness, and malaise. Lassa fever symptoms, diagnosis, treatments and causes. Dozens of symptoms are associated with lassa fever, ranging from malaise to bleeding from the mouth. Neighboring countries are also at risk, as the animal vector for lassa virus, the multimammate rat mastomys natalensis is distributed throughout the region.
A small percentage of people infected with lassa fever will develop complications like hemorrhaging, respiratory distress, tremors, encephalitis, and multiorgan failure. The symptoms of lassa fever can be nonspecific and mimic those of other endemic infections, especially early in illness, making a clinical diagnosis difficult. Measuring temperature within 24 hours without the use of anti pyretics for patients who present with apparently normal temperature. The ebola virus is mainly carried by fruit bats or transmitted through humantohuman contact. Lassa fever is one of the hemorrhagic fever viruses like ebola virus, marburg virus, and others. Lassa fever is difficult to diagnose because its symptoms are nonspecific and varies from individual to individual especially in the early course of the disease. The illness was discovered in lassa, borno state where it was first reported. Lassa fever in the netherlands ex sierra leone ecdc. The signs and symptoms of lassa fever may not start immediately the person is exposed to the virus. Benin was last affected by lassa fever over a 4 monthperiod in 20142015 when 16 cases were reported and 9 people died. Brief history, diagnosing, and symptoms of lassa fever. Lassa fever lf is an acute viral haemorrhagic infection, endemic in west africa.
In 35 50% of hospitalized cases the disease may progress to its severe form, with. Lassa fever causes, symptoms, treatment, diagnosis and. Difference between ebola and lassa fever ebola vs lassa fever. After a few days, headache, sore throat, muscle pain, chest pain, nausea, vomiting, diarrhoea, cough, and abdominal pain may follow. Prevalence of symptoms and outcomes among patients with laboratoryconfirmed lassa fever, nigeria, january 1may 6, 2018 aors and 95% cis calculated by using a binomial logistic regression model for fatal outcomes adjusted for age and sex. The areas where lassa is found are the areas where this rat is found. According to reports, lassa virus was first discovered in 1969 in the town of lassa, in borno state, nigeria. Lassa fever outbreak hits nigeria infectioncontrol. Jul 31, 2017 lassa fever is known to be endemic in benin where it was diagnosed for the first time in november 2014, ghana diagnosed for the first time in october 2011, guinea, liberia, mali diagnosed for the first time in february 2009, sierra leone, and nigeria, but probably exists in other west african countries as well.
Introduction to lassa fever world health organization. Lesson learned from the investigation and response of lassa fever. Failure of the nigerian health system to prioritise preparedness activities has been detrimental for prompt control of lassa fever, which requires robust laboratory. Ribavirin, an antiviral drug, has been used to successfully treat patients with lassa fever. Lassa fever is one of a group of viral hemorrhagic fevers vhfs. Lassa fever is spread through direct contact with the. It is most common in a large region of west africa, and is named after the nigerian town where it was. In its severest form, if it is not treated, the disease can lead to death. Deadly lassafever outbreak tests nigerias revamped health. It is an acute viral hemorrhagic fever caused by the lassa virus. Jun 27, 2018 the symptoms of lassa fever vary widely, and diagnosis can be difficult.
Nov 23, 2012 lassa fever in children and infants significant cause of pediatric hospitalizations in some areas of west africa signs and symptoms most often similar to adults swollen baby syndrome edemaanasarca abdominal distension bleeding poor prognosis 17. Lassa fever is endemic in most parts of sierra leone. Lassa virus is known to be responsible for a severe hemorrhagic fever characterized by fever, muscle aches, sore throat, nausea, vomiting, and chest and abdominal pain centers for. So far, 78 people are confirmed to have died from lassa fever. The lassa virus is transmitted to humans mainly through handling rats, food or house hold items contaminated by rats urine and faeces. Unlike ebola virus, lassa fever is not as contagious person to person, nor as deadly. It is an acute febrile viral illness lasting one to four weeks, and it occurs in west africa and some areas beyond. The exposure is usually to a multimammate rat mastomys natalensis. Lassa fever, on the other hand, is carried and transmitted by the natal multimammate mouse.
Currently, 3126 contactshave beenidentified, and 1586 are being. Early signs and symptoms of lassa fever healthfactsng. Lassa fever full recovery without ribavarin treatment. Diagnosis of lassa fever and the isolation and management.
The purpose of this project is to develop an antiviral drug to treat and prevent lassa fever. Lassa fever is an acute viral illness that occurs in west africa. Confirmatory diag nosis and treatment ribavirin is difficult. A free powerpoint ppt presentation displayed as a flash slide show on id. Mild symptoms include slight fever, feeling tired and weak, and headache. Lassa fever is an illness caused by lassa virus, a singlestranded rna hemorrhagic fever virus from the family arenaviridae.
While lassa fever is mild or has no observable symptoms in about 80% of people infected with the virus, the remaining 20% have a severe multisystem disease. Among those infected are 16 health workers in six states, four of whom have died. Gradual onset of fever, malaise and general weakness after a few days. Lassa fever is a viral disease spread by the the multimammate rat.
In the remaining 20 percent of cases, lassa fever becomes serious. The most common complication of lassa fever is hearing loss. Causes, symptoms, and diagnosis medical news today. Such infections are often asymptomatic, but in those who become ill, the disease can range from an uncomplicated fever of unknown origin to a fulminating hemorrhagic disease.
Lassa fever is a viral illness that typically occurs in west africa. It is endemic in parts of west africa including sierra leone, liberia, guinea and nigeria. Pathophysiology and treatment of lassa fever springerlink. The diagnosis of lassa fever should be considered in febrile patients returning from west africa, especially if they have been in rural areas or hospitals in countries where lassa fever is endemic. Lassa fever presents with symptoms and signs indistinguishable from those of febrile. When symptoms occur they typically include fever, weakness, headaches, vomiting, and muscle pains. Mild symptoms include things like slight fever, general malaise as well as weakness, and headache.
Because the symptoms of lassa fever are so varied and nonspecific, clinical diagnosis is often difficult. Lassa fever, also known as lassa hemorrhagic fever lhf, is a type of viral hemorrhagic fever caused by the lassa virus. Find out more about the symptoms, diagnosis, and treatment of lassa fever, steps to prevent it, and a vaccine that researchers hope is in the pipeline. Treatment of lassa fever cases requires supportive care. Symptoms of lassa fever can include fever, chest pain, sore throat, abdominal and back pain, cough, vomiting, diarrhea, conjunctivitis red eyes, and facial swelling. Mild symptoms include slight fever, general malaise and weakness, and headache. For the majority of lassa fever virus infections approximately 80%, symptoms are mild and are undiagnosed. Lassa fever lf is a viral hemorrhagic disease caused by the lassa virus lasv and. Lassa virus is typically transmitted by the urine or feces of mastomys rats to humans. Development of a therapeutic for lassa fever national. Three states are reporting 85% of all confirmed cases. Current treatment options are inadequate, relying primarily on supportive care.
It is widespread in many african countries, such as liberia and sierra leone, and it can be. Ppt lassa fever powerpoint presentation free to view id. Since november 2015, at least 10 states in nigeria have been affected by an outbreak of lassa fever, an acute viral disease that causes fever, muscle pain, hemorrhage and sometimes death. Signs or symptoms of lassa fever generally occur weeks as soon as the patient comes into exposure to the virus. 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 outbreak, nigeria, januarymay 2018 lassa fever lf is endemic to nigeria, where the disease causes substantial rates of illness and death. Researchers in nigeria are racing to identify cases of lassa fever and to understand why the ongoing outbreak is the worst on record. Many of those infected by the virus do not develop symptoms.
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