Full Answer
How long does Lassa fever last?
of all cases, Lassa fever is fatal, and around 15 to 20 percent of all hospitalizations for the disease will end in death. Death can occur within 2 weeks after the onset of symptoms due to multiple organ failure. One of the most common complications of Lassa fever is hearing loss, which occurs in around 1 in 3
Is there a treatment for Lassa fever?
Treatment and prophylaxis The antiviral drug ribavirin seems to be an effective treatment for Lassa fever if given early on in the course of clinical illness. There is no evidence to support the role of ribavirin as post-exposure prophylactic treatment for Lassa fever. There is currently no vaccine that protects against Lassa fever.
How often do Lassa fever outbreaks occur in Nigeria?
Lassa fever outbreaks occur every year. The number of people infected peaks between December and June. A large outbreak was reported by the Nigeria Centre for Disease Control that began early in 2018. What is Lassa fever? Lassa fever is an illness caused by Lassa virus, a single-stranded RNA hemorrhagic fever virus from the family Arenaviridae.
What are the symptoms of Lassa virus?
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.
How long does Lassa last?
Lassa fever is an illness caused by Lassa virus, a single-stranded RNA hemorrhagic fever virus from the family Arenaviridae. It is an acute febrile viral illness lasting one to four weeks, and it occurs in West Africa and some areas beyond.
Is Lassa fever treatable?
Ribavirin, an antiviral drug, has been used with success in Lassa fever patients. It has been shown to be most effective when given early in the course of the illness.
How long does Lassa fever virus survive outside the body?
SURVIVAL OUTSIDE HOST: The virus is stable as an aerosol, particularly at low relative humidity (30 % RH ). The biological half-live at both 24°C and 32°C ranges from 10.1 to 54.6 minutes 20.
What is the survival rate of Lassa fever?
Approximately 15%-20% of patients hospitalized for Lassa fever die from the illness. However, only 1% of all Lassa virus infections result in death.
What does Lassa fever do to the body?
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.
How long does it take for Lassa fever to manifest?
Signs and symptoms of Lassa fever typically occur 1-3 weeks after the patient comes into contact with the virus. For the majority of Lassa fever virus infections (approximately 80%), symptoms are mild and are undiagnosed. Mild symptoms include slight fever, general malaise and weakness, and headache.
Does rat bite cause Lassa fever?
Lassa fever is an acute, viral disease carried by a type of rat that is common in West Africa.
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.
Is there vaccine for Lassa fever?
Currently, there is no licensed vaccine for Lassa fever, although numerous candidates are in the development pipeline.
Can Lassa spread person to person?
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.
How do you test for Lassa fever?
Lassa fever is most often diagnosed by using enzyme-linked immunosorbent serologic assays (ELISA), which detect IgM and IgG antibodies as well as Lassa antigen. Reverse transcription-polymerase chain reaction (RT-PCR) can be used in the early stage of disease.
How is Lassa fever mostly spread?
Lassa fever causes around 5,000 deaths per year. It is spread through the feces and urine of the multimammate rat (Mastomys natalensis). It is most common in Sierra Leone, Liberia, Guinea, and Nigeria. Symptoms are varied and include pulmonary, cardiac, and neurological problems.
How long does it take for a Lassa fever to show symptoms?
The incubation period for Lassa fever is variable, from six days to three weeks. Most people have mild or no symptoms. British researchers suggest the incubation period varies from seven to 10 days and in some people, up to about 21 days.
What is Lassa fever?
Lassa fever is one of the hemorrhagic fevers and may appear with signs and symptoms like Ebola or Marburg hemorrhagic fever viruses, and until these viruses are ruled out, suspected cases must be managed with infection control precautions to prevent contact with blood, body fluids, and contaminated surfaces.
How does Lassa fever spread?
It is spread to people through contact with household items, food, water, or air contaminated with the droppings or urine of infected multimammate rats ( Mastomyces natalensis ).
How many people die from Lassa fever in a year?
There are 100,000 to 300,000 cases of Lassa fever each year in the world. Lassa fever heavily impacts Sierra Leone and Liberia in particular, where it causes an estimated 5,000 deaths and about 10%-16% of admissions to hospitals each year. Deaths are especially common in children.
Why do people with Lassa fever have no symptoms?
Because most Lassa fever viral infections cause no symptoms, and because people with acute deafness have been shown to have high antibody levels to Lassa virus, suggesting recent infection, Lassa fever virus is believed to be a common cause of sudden deafness in affected areas.
How to diagnose Lassa fever?
How do physicians diagnose Lassa fever? 1 Laboratory tests include enzyme-linked immunosorbent serologic assays ( ELISA) for Lassa IgM and IgG antibodies and Lassa antigen. For definitive testing, virus can be grown in culture in seven to 10 days; reverse transcriptase polymerase chain reaction (RT- PCR) assay is also available but often limited to research. 2 Immunohistochemistry stains performed on tissue specimens can also be used to make a postmortem diagnosis.
How is Lassa transmitted?
Lassa virus is typically transmitted by the urine or feces of Mastomys rats to humans . Health workers may be infected by direct contact with blood, body fluids, urine, or stool of a patient with Lassa fever. Lassa fever occurs primarily in West Africa in areas where these rodents live.
How long does Lassa fever last?
Lassa fever is an acute viral haemorrhagic illness of 2-21 days duration that occurs in West Africa. The Lassa virus is transmitted to humans via contact with food or household items contaminated with rodent urine or faeces. Person-to-person infections and laboratory transmission can also occur, particularly in hospitals lacking adequate infection ...
What should be done for a patient with a Lassa fever?
Health-care workers caring for patients with suspected or confirmed Lassa fever should apply extra infection control measures to prevent contact with the patient’s blood and body fluids and contaminated surfaces or materials such as clothing and bedding.
How does Lassa virus spread?
Humans usually become infected with Lassa virus from exposure to urine or faeces of infected Mastomys rats. 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. There is no epidemiological evidence supporting airborne spread between ...
What is the host of Lassa virus?
The animal reservoir, or host, of Lassa virus is a rodent of the genus Mastomys, commonly known as the “multimammate rat.”. Mastomys rats infected with Lassa virus do not become ill, but they can shed the virus in their urine and faeces.
Why is Lassa fever so difficult to diagnose?
Lassa fever is difficult to distinguish from other viral haemorrhagic fevers such as Ebola virus disease as well as other diseases that cause fever, including malaria, shigellosis, ...
How to prevent Lassa fever?
Prevention of Lassa fever relies on promoting good “community hygiene” to discourage rodents from entering homes. Effective measures include storing grain and other foodstuffs in rodent-proof containers, disposing of garbage far from the home, maintaining clean households and keeping cats.
Where is the Lassa virus most likely to be transmitted?
Sexual transmission of Lassa virus has been reported. Lassa fever occurs in all age groups and both sexes. Persons at greatest risk are those living in rural areas where Mastomys are usually found, especially in communities with poor sanitation or crowded living conditions.
How long does it take for a lassa to show symptoms?
The clinical presentation of Lassa usually begins with insidious progression of fever and general malaise that can progress to more severe symptoms within 1-2 weeks. Hepatitis (inflammation of the liver) is frequent and moderately severe in Lassa.
What is the hallmark of Lassa virus?
One of the hallmarks of Lassa virus infection is the apparent absence of functional antibodies during acute infection . A fundamental understanding of the mechanisms of antibody-mediated neutralization of Lassa virus may have significant implications for the generation of antibody-based therapeutics or epitope-targeted vaccines.
What is the color of Lassa?
The serum from these patients can turn brownish in color and a significant degree of hemolysis can be observed.
Where is Lassa fever?
Lassa. Lassa fever (Lassa) is an acute viral hemorrhagic fever endemic to West Africa. Since its discovery in 1969 in the village of Lassa in Borno State, Nigeria, there have been countless outbreaks of various magnitude and severity across West Africa. It is estimated that many thousands of people are infected with the virus annually, ...
Where are Lassa viruses found?
However, concerns exist that there may be Lassa (and Lassa-like) viruses in other countries such as Central African Republic, Burkina Faso, Ghana, Benin, and Cameroon – some of which have had sporadic cases.
Is lassa a pregnancy risk?
Lassa in pregnant women is especially severe and is associated with infection of the fetus and loss of the fetus or newborn in 90% of the cases. The risk of death is also significantly higher for pregnant mothers in the third trimester and evacuation of the uterus significantly improves the mother’s odds of survival.
Is Lassa a human transmission?
Despite healthcare workers being at high risk of infection, contact in households with persons ill, or recently ill with Lassa, as well as sexual contact with someone convalescent with Lassa are all also important risk factors for human-to-human transmission.
What is 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. Trusted Source.
How to diagnose Lassa fever?
Lassa fever is generally diagnosed by using enzyme-linked immunosorbent serologic assays (ELISA). These detect IgM and IgG antibodies and Lassa antigens. Reverse transcription-polymerase chain reaction (RT-PCR) can also be used in the early stages of the disease.
How many people die from Lassa fever in West Africa?
The disease is endemic to a number of West African countries. Rough estimates suggest there are between 100,000 and 300,000 cases. of Lassa fever each year in West Africa, and approximately 5,000 deaths due to the disease.
What is the most common complication of Lassa fever?
One of the most common complications of Lassa fever is hearing loss, which occurs in around 1 in 3. Trusted Source. infections. This hearing loss varies in degree and is not necessarily related to the severity of the symptoms. Deafness caused by Lassa fever can be permanent and total.
Where did Lassa fever originate?
Lassa fever is a viral hemorrhagic disease. It can be serious. Lassa fever was first discovered in Nigeria, when two missionary nurses became ill with the virus in 1969. Its name is derived from the village of Lassa, where it was first documented.
Is Lassa fever a hemorrhagic fever?
The symptoms of Lassa fever vary widely, and diagnosis can be difficult. Clinically, the disease can resemble other viral hemorrhagic fevers, including the Ebola virus, malaria, and typ hoid. for Lassa fever are laboratory-based, and the handling of specimens can be hazardous.
Is Lassa fever fatal?
In the remaining 20 percent of cases, Lassa fever becomes serious. of all cases, Lassa fever is fatal, and around 15 to 20 percent of all hospitalizations for the disease will end in death.
What is Lassa fever?
Lassa fever is a viral haemorrhagic fever that spreads to humans through contact with infected rats. “One of the major challenges of treating Lassa fever is the nature of the disease itself because at the onset, it mimics diseases like malaria,” says Dr Umezurike Daniel, the health commissioner of Nigeria’s Ebonyi state.
How many Lassa fever cases are there in Nigeria?
In March 2018, MSF teams joined the response to one of Nigeria’s largest ever Lassa fever outbreaks. Twenty-three states in Nigeria reported 3,498 Lassa fever suspects during 2018, with 45 healthcare workers among the 633 confirmed cases. Video.
Where is Lassa fever found?
“It has been half a century since Lassa fever was discovered in northern Nigeria, but healthcare workers in West Africa still urgently need appropriate equipment and training to safely manage patients ...
How many Lassa cases were there in 2018?
On 25 February 2018, there were 1081 suspected cases and 90 reported deaths; 317 of the cases and 72 deaths were confirmed as Lassa which increased to a total of 431 reported cases in 2018.
What is a Lassa fever?
Lassa fever, also known as Lassa hemorrhagic fever ( LHF ), is a type of viral hemorrhagic fever caused by the Lassa virus. Many of those infected by the virus do not develop symptoms. When symptoms occur they typically include fever, weakness, headaches, vomiting, and muscle pains.
Why is it important to deliver a baby with Lassa fever?
When Lassa fever infects pregnant women late in their third trimester, inducing delivery is necessary for the mother to have a good chance of survival. This is because the virus has an affinity for the placenta and other highly vascular tissues. The fetus has only a one in ten chance of survival no matter what course of action is taken; hence, the focus is always on saving the life of the mother. Following delivery, women should receive the same treatment as other people with Lassa fever.
Where does Lassa spread?
This is probably the most common mouse in equatorial Africa, common in human households and eaten as a delicacy in some areas.
Where is Lassa fever found?
The virus was first described in 1969 from a case in the town of Lassa, in Borno State, Nigeria. Lassa fever is relatively common in West Africa including the countries of Nigeria, Liberia, Sierra Leone, Guinea, and Ghana. There are about 300,000 to 500,000 cases which result in 5,000 deaths a year.
Is Lassa fever a hemorrhagic fever?
Lassa fever can be difficult to distinguish clinically from other viral hemorrhagic fevers, such as Ebola virus disease. A combination of pharyngitis, pain behind the sternum, presence of excess protein in the urine and fever can indicate Lassa fever with higher specificity.
Is there a test for Lassa?
The FDA has yet to approve a widely validated laboratory test for Lassa, but there are tests that have been able to provide definitive proof of the presence of the LASV virus. These tests include cell cultures, PCR, ELISA antigen assays, plaque neutralization assays, and immunofluorescence essays.
Background
Symptoms 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. In severe cases facial swelling, fl...
Transmission
- Humans usually become infected with Lassa virus from exposure to urine or faeces of infected Mastomysrats. 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. There is no epidemiological evidence supporting airborne spread between humans. Person-to-person trans…
Diagnosis
- Because the symptoms of Lassa fever are so varied and non-specific, clinical diagnosis is often difficult, especially early in the course of the disease. Lassa fever is difficult to distinguish from other viral haemorrhagic fevers such as Ebola virus disease as well as other diseases that cause fever, including malaria, shigellosis, typhoid fever and yellow fever. Definitive diagnosis requires …
Treatment and Prophylaxis
- The antiviral drug ribavirin seems to be an effective treatment for Lassa fever if given early on in the course of clinical illness. There is no evidence to support the role of ribavirin as post-exposure prophylactic treatment for Lassa fever. There is currently no vaccine that protects against Lassa fever.
Prevention and Control
- Prevention of Lassa fever relies on promoting good “community hygiene” to discourage rodents from entering homes. Effective measures include storing grain and other foodstuffs in rodent-proof containers, disposing of garbage far from the home, maintaining clean households and keeping cats. Because Mastomysare so abundant in endemic areas, it is not possible to comple…
Who Response
- The Ministries of Health of Guinea, Liberia and Sierra Leone, WHO, the Office of United States Foreign Disaster Assistance, the United Nations, and other partners have worked together to establish the Mano River Union Lassa Fever Network. The programme supports these 3 countries in developing national prevention strategies and enhancing laboratory diagnostics for Lassa fev…
Geographical Distribution
Infections with Lassa Virus
- Humans contract the virus primarily through contact with the contaminated excreta of Mastomys natalensis rodents (commonly known as the Multimammate rat), which is the natural reservoir for the virus. Little is known regarding the transmission of the virus from the rodent reservoir to the human host, although there is compelling evidence that Arenaviruses are stable and infectious b…
Diagnosis and Symptoms of Lassa
- In the early stages, Lassa is often misdiagnosed as influenza, malaria, or other common diseases, and as a result many patients fail to receive appropriate medical treatment. Making a correct diagnosis of Lassa is made difficult by the wide spectrum of clinical effects that manifest, ranging from asymptomatic to multi-organ system failure and death. The clinical presentation of Lassa …
Treatment of Lassa
- No vaccine for Lassa is currently available for use in humans, and the only available drug, ribavirin, is only effective if administered early in infection (within the first 6 days after disease onset). One of the hallmarks of Lassa virus infection is the apparent absence of functional antibodies during acute infection. A fundamental understanding ...
Virology
- Lassa virus is a member of the Arenaviridae family. Members of the virus families Arenaviridae (Lassa, Lujo, Junin, Guanarito and Machupo), Filoviridae (Ebola and Marburg), and Bunyaviridae(Rift Valley Fever and Crimean Congo hemorrhagic fever) are the agents of greatest concern to public health and bioterrorism. The Lassa virus particle is round, oval, or pleomorphic…