GeneHealth - Your precision medicine

Lassa Fever

Disease Details

Family Health Simplified

Buy Membership

Description: Lassa fever is an acute viral hemorrhagic illness caused by the Lassa virus, primarily transmitted to humans through contact with food or household items contaminated with rodent urine or feces.
Type: Lassa fever is an acute viral hemorrhagic illness. The disease is caused by the Lassa virus, which is an RNA virus from the Arenaviridae family. The type of genetic transmission for Lassa fever does not involve human-to-human genetic transmission. Instead, it is primarily zoonotic, transmitted to humans from rodents, specifically the multimammate rat (Mastomys natalensis), through direct contact with the rodent's urine, feces, saliva, or blood. Human-to-human transmission can also occur through direct contact with the blood, tissue, secretions, or excretions of an infected person.
Signs And Symptoms: Onset of symptoms is typically 7 to 21 days after exposure. In 80% of those who are infected few or no symptoms occur. These mild symptoms may include fever, tiredness, weakness, and headache. In 20% of people more severe symptoms such as bleeding gums, breathing problems, vomiting, chest pain, or dangerously low blood pressure may occur. Long term complications may include hearing loss. In those who are pregnant, miscarriage may occur in 95% of child-bearing females . 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.In cases in which death occurs, this typically occurs within 14 days of onset. About 1% of all Lassa virus infections result in death. Approximately 15%-20% of those who have required hospitalization for Lassa fever die. The risk of death is greater in those who are pregnant. A "Swollen baby syndrome" may occur in newborns, infants and toddlers with pitting edema, abdominal distension and bleeding.
Prognosis: About 15–20% of hospitalized people with Lassa fever will die from the illness. The overall case fatality rate is estimated to be 1%, but during epidemics, mortality can climb as high as 50%. The mortality rate is greater than 80% when it occurs in pregnant women during their third trimester; fetal death also occurs in nearly all those cases. Abortion decreases the risk of death to the mother. Some survivors experience lasting effects of the disease, and can include partial or complete deafness.Because of treatment with ribavirin, fatality rates have declined.
Onset: Lassa fever is a viral hemorrhagic illness. The onset typically occurs 1 to 3 weeks after exposure to the virus. Symptoms can include fever, malaise, headache, sore throat, muscle pain, chest pain, nausea, vomiting, diarrhea, cough, and abdominal pain.
Prevalence: Lassa fever is an acute viral hemorrhagic illness prevalent in West Africa. It is caused by the Lassa virus, which is primarily transmitted to humans via contact with food or household items contaminated by rodent urine or feces. The disease is endemic in several West African countries, including Nigeria, Liberia, Sierra Leone, Guinea, and Ghana. Annually, there are an estimated 100,000 to 300,000 infections, with around 5,000 deaths. The prevalence can vary greatly by region and can significantly increase during outbreaks.
Epidemiology: There are about 300,000 to 500,000 cases which result in 5,000 deaths a year. One estimate places the number as high as 3 million cases per year.Estimates of Lassa fever are complicated by the lack of easy-available diagnosis, limited public health surveillance infrastructure, and high clustering of incidence near high intensity sampling.The infection affects females 1.2 times more than males. The age group predominantly infected is 21–30 years.
Intractability: Lassa fever is not considered intractable. Though it can be serious and potentially fatal, it is generally treatable, especially when diagnosed early. Treatment often involves the use of antiviral medication such as ribavirin. Additionally, supportive care to manage symptoms and complications improves outcomes. Early detection and prompt medical intervention are key to managing the disease effectively.
Disease Severity: Lassa fever can range from mild to severe. Some individuals may experience no symptoms or mild symptoms, while others can develop severe symptoms including hemorrhaging, respiratory distress, shock, and multi-organ failure. The case-fatality rate among those who develop severe disease is approximately 1%.
Healthcare Professionals: Disease Ontology ID - DOID:9537
Pathophysiology: **Pathophysiology of Lassa Fever:**

Lassa fever is an acute viral hemorrhagic illness caused by the Lassa virus, a member of the Arenaviridae family. The virus is primarily transmitted to humans through contact with food or household items contaminated by the urine or feces of infected Mastomys rats. Person-to-person transmission can also occur via exposure to the blood, tissues, secretions, or excretions of infected individuals.

Once the Lassa virus enters the body:

1. **Viral Entry and Spread**: The virus initially infects cells at the entry site and then spreads through the bloodstream (viremia) to various organs, including the liver, spleen, and kidneys.

2. **Immune Response**: The body mounts an immune response, but in severe cases, the virus evades the immune system, leading to a systemic infection. The immune response can produce inflammatory cytokines, contributing to the disease's symptoms and complications.

3. **Endothelial Damage**: The virus causes damage to endothelial cells (cells lining blood vessels), leading to increased vascular permeability. This results in plasma leakage, edema, and hemorrhagic manifestations in the later stages of the disease.

4. **Organ Involvement**: The liver, being one of the primary target organs, may suffer viral hepatitis, leading to liver damage and dysfunction. Multi-organ involvement can result in renal impairment, respiratory distress, cardiovascular collapse, and central nervous system effects.

5. **Clinical Manifestations**: The incubation period is typically 1-3 weeks. Early symptoms include fever, malaise, and muscle pain, progressing to sore throat, nausea, vomiting, diarrhea, and abdominal pain. Severe cases may develop bleeding from mucosal surfaces, hypotension, neurological symptoms, shock, and multi-organ failure.

Understanding the pathophysiology is crucial for diagnosing and managing Lassa fever, highlighting the importance of early detection and supportive care to reduce mortality.
Carrier Status: Carrier status for Lassa fever: The primary carriers of the Lassa virus are multimammate rats (Mastomys species), specifically Mastomys natalensis. These rodents can shed the virus in their urine and feces, which can then contaminate food or household items. Humans can contract the virus through contact with these contaminated materials.
Mechanism: Lassa fever is an acute viral hemorrhagic illness caused by the Lassa virus, part of the Arenaviridae family.

**Mechanism:**

The Lassa virus is predominantly transmitted to humans through contact with food or household items contaminated with the urine or feces of infected Mastomys rats. Human-to-human transmission can occur through direct contact with the blood, tissue, secretions, or excretions of infected individuals, or through contaminated medical equipment.

Once the virus enters the body, it targets endothelial cells, macrophages, and dendritic cells. The virus replicates, leading to cell damage, immune system dysregulation, and a pro-inflammatory cytokine response.

**Molecular Mechanisms:**

1. **Entry and Fusion:**
- The Lassa virus attaches to host cells via its glycoprotein (GP) complex interacting with the alpha-dystroglycan (α-DG) receptor on the cell surface.
- Following attachment, the virus is internalized through endocytosis and traffics to acidic endosomes.
- The acidic environment in endosomes triggers conformational changes in the GP complex, facilitating membrane fusion and release of the viral ribonucleoprotein complexes into the cytoplasm.

2. **Replication:**
- The Lassa virus RNA genome is segmented and ambisense, requiring transcription and translation of both negative and positive strands.
- The viral RNA-dependent RNA polymerase (L protein) transcribes the genome into mRNA and replicates it.
- Viral proteins are synthesized in the cytoplasm, and the glycoprotein precursor is processed in the endoplasmic reticulum and Golgi apparatus.

3. **Immune Evasion:**
- Lassa virus employs several strategies to evade the host immune response, including inhibition of interferon (IFN) production and signaling.
- The viral nucleoprotein (NP) has exonuclease activity that degrades double-stranded RNA, reducing the detection of viral RNA by host sensors.
- The Z protein interferes with cellular antiviral responses, further contributing to immune evasion.

4. **Pathogenesis:**
- The destruction of infected cells, alongside the dysregulated immune response, leads to vascular leakage and multi-organ failure, which are characteristic of severe cases of Lassa fever.
- Cytokine storm and endothelial dysfunction are significant contributors to the disease's severity.

Understanding these mechanisms is crucial for developing targeted therapies and improving disease management strategies for Lassa fever.
Treatment: Treatment is directed at addressing dehydration and improving symptoms. All persons suspected of Lassa fever infection should be admitted to isolation facilities and their body fluids and excreta properly disposed of.
Compassionate Use Treatment: For Lassa Fever, compassionate use and experimental treatments may include:

1. **Ribavirin:** An antiviral drug that has shown some effectiveness when administered early in the course of the disease.
2. **Favipiravir:** Another antiviral that has been studied for its potential use in treating Lassa Fever.
3. **Monoclonal Antibodies:** Investigational treatments involving antibodies specifically targeting the Lassa virus are being explored.
4. **Supportive Care:** Intensive supportive care is essential, and this includes maintaining hydration, electrolyte balance, and organ function.
5. **Convalescent Plasma:** Use of plasma from recovered patients to provide antibodies against the virus is being investigated.

These treatments are typically considered experimental and are used under specific protocols and regulatory approvals.
Lifestyle Recommendations: Lifestyle recommendations for Lassa fever include:

1. **Reduce Exposure to Rodents:**
- Keep homes and surroundings clean to deter rodent infestation.
- Store food in rodent-proof containers.
- Dispose of garbage far from living areas.

2. **Improve Hygiene Practices:**
- Wash hands regularly with soap and water.
- Avoid contact with blood and bodily fluids of infected individuals.

3. **Safe Food Practices:**
- Cook food thoroughly to kill potential pathogens.
- Avoid consuming bush meat.

4. **Strengthen Community Awareness:**
- Educate communities about the risks and ways to prevent Lassa fever.
- Promote early medical consultation for fevers, especially in endemic areas.

5. **Travel Precautions:**
- Limit travel to areas experiencing outbreaks.
- Use protective measures, such as mosquito nets, even though Lassa fever is primarily rodent-borne.

Following these lifestyle recommendations can help reduce the risk of contracting and spreading Lassa fever.
Medication: The antiviral medication ribavirin has been recommended, but evidence to support its use is weak. Some evidence has found that it may worsen outcomes in certain cases. Fluid replacement, blood transfusions, and medication for low blood pressure may be required. Intravenous interferon therapy has also been used.
Repurposable Drugs: There are several drugs that have been investigated for repurposing against Lassa fever, a viral hemorrhagic illness caused by the Lassa virus. Ribavirin, an antiviral medication, is the most commonly used treatment and has shown efficacy when administered early in the course of the illness. Other antiviral agents such as Favipiravir and Remdesivir have also been studied for their potential effectiveness against Lassa fever, though their use is still under investigation and not widely adopted for this specific disease.
Metabolites: Lassa fever is an acute viral hemorrhagic illness caused by Lassa virus. The topic of metabolites in the context of Lassa fever may refer to the metabolic changes and biomarkers resulting from the infection. However, there's a lack of specific, detailed information about individual metabolites directly linked to Lassa fever.

In general, viral infections can alter host metabolism, and typical changes might include variations in glucose metabolism, lipid profiles, and amino acid levels. These alterations often reflect the body's response to viral infection and inflammation. For precise details, specific research studies focused on the metabolic profile of Lassa fever patients would be required.

If "nan" refers to nanotechnology or nanoparticles, it suggests the potential use of nanomaterials in diagnostics or treatment. Nanotechnology could be explored for developing advanced diagnostic tools to detect Lassa virus more accurately or for delivering targeted antiviral therapies. However, this is an area of ongoing research and has not yet achieved widespread clinical application for Lassa fever.
Nutraceuticals: There is no specific information on nutraceuticals being effective against Lassa fever. The primary treatment for Lassa fever involves supportive care and the antiviral drug ribavirin. Nutraceuticals, which include vitamins, minerals, and other dietary supplements, have not been established as a treatment for this viral infection. For accurate guidance, consult healthcare professionals.
Peptides: Lassa fever is an acute viral hemorrhagic illness caused by the Lassa virus. Peptides, as antigens, can play a role in the development of diagnostic tools and potential treatments. Nanotechnology can also offer advancements in diagnostics, targeted drug delivery, and vaccine development for Lassa fever by enhancing the sensitivity and specificity of detection methods and increasing the efficacy of therapeutic interventions.