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La Crosse Encephalitis

Disease Details

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Description: La Crosse encephalitis is a viral disease caused by the La Crosse virus, primarily transmitted by the bite of infected Aedes mosquitoes, leading to inflammation of the brain and potentially severe neurological symptoms.
Type: La Crosse encephalitis is a type of viral disease. The virus is primarily transmitted to humans through the bite of an infected mosquito, specifically the Aedes triseriatus species. It is not transmitted genetically from person to person.
Signs And Symptoms: It takes 5 to 15 days after the bite of an infected mosquito to develop symptoms of LACV disease. Most people infected with the virus do not have symptoms. Symptoms may include nausea, headache, vomiting and fever in milder cases.
Severe disease occurs most commonly in children under the age of 16 and is characterized by, and seizures, coma, paralysis and permanent brain damage and a variety of neurological sequelae after recovery. Death from LAC encephalitis occurs in less than 1% of clinical cases. In many clinical settings, pediatric cases presenting with CNS involvement are routinely screened for herpes simplex or enteroviral causes. Since there is no specific treatment for LAC encephalitis, physicians often do not request the tests required to specifically identify LAC virus, and the cases are reported as aseptic meningitis or viral encephalitis of unknown cause.
As with many infections, the very young, the very old and the immunocompromised are at a higher risk of developing severe symptoms.
Prognosis: For La Crosse encephalitis, the prognosis is generally favorable, especially in children. Most people recover fully, although some may experience prolonged fatigue, headaches, or other minor neurological symptoms. Severe cases can lead to long-term neurological damage or, in rare instances, be fatal. Prompt medical attention and supportive care improve the outcome significantly.
Onset: La Crosse encephalitis typically has an onset of symptoms 5 to 15 days after being bitten by an infected mosquito. Initial symptoms often include fever, headache, nausea, vomiting, and fatigue. More severe symptoms can develop, such as inflammation of the brain (encephalitis), seizures, or coma, particularly in children.
Prevalence: La Crosse encephalitis is a rare but potentially serious disease caused by the La Crosse virus, primarily transmitted through the bite of an infected Aedes mosquito. The number of reported cases can vary significantly from year to year. In the United States, where the disease is most commonly found, there are typically about 50 to 150 cases reported annually. Most cases occur in the upper Midwestern, mid-Atlantic, and southeastern states. Children under the age of 16 are most commonly affected.
Epidemiology: La Crosse encephalitis was discovered in 1965, after the virus was isolated from stored brain and spinal tissue of a child who died of an unknown infection in La Crosse, Wisconsin in 1960. It occurs in the Appalachian and Midwestern regions of the United States. Recently there has been an increase of cases in the southeastern United States. An explanation to this may be that the mosquito Aedes albopictus is also an efficient vector of La Crosse virus. Aedes albopictus is a species that has entered the US and spread across the SE of the US and replaced Aedes aegypti in most areas (which is not an efficient vector of LAC).
Historically, most cases of LAC encephalitis occur in the upper Midwestern states (Minnesota, Wisconsin, Iowa, Illinois, Indiana, and Ohio). Recently, more cases are being reported from states in the mid-Atlantic (West Virginia, Virginia and North Carolina) and southeastern (Alabama and Mississippi) regions of the country. It has long been suspected that LAC encephalitis has a broader distribution and a higher incidence in the eastern United States, but is under-reported because the causal agent is often not specifically identified.LAC encephalitis cases occur primarily from late spring through early fall, but in subtropical areas where the mosquito is found (e.g., the Gulf states), rare cases can occur in winter.
According to the CDC, between 2004 and 2013 there were 787 total cases of La Crosse encephalitis and 11 deaths in the U.S.Looking at the distribution of cases across the United States by state, between 2004 and 2013 the most cases of La Crosse encephalitis was in North Carolina. North Carolina had 184 total cases, followed by Ohio with 178 total cases.
Intractability: La Crosse encephalitis is typically not considered intractable. While the disease can be serious and occasionally fatal, particularly in children, most patients recover fully with supportive care. The illness generally includes symptoms such as fever, headache, nausea, vomiting, and fatigue, and in severe cases, encephalitis may occur. Management focuses on supportive treatments as there is no specific antiviral therapy for La Crosse encephalitis.
Disease Severity: La Crosse encephalitis generally has a low mortality rate but can cause severe neurological complications, especially in children. Most cases are mild and involve symptoms such as fever, headache, nausea, and fatigue. Severe cases can lead to seizures, coma, and long-term neurological damage.
Healthcare Professionals: Disease Ontology ID - DOID:0050118
Pathophysiology: Pathophysiology of La Crosse Encephalitis:

La Crosse encephalitis is caused by the La Crosse virus, a member of the Bunyaviridae family, transmitted primarily through the bite of infected Aedes triseriatus mosquitoes. Once the virus enters the bloodstream, it can cross the blood-brain barrier and infect neuronal cells in the central nervous system (CNS). The infection leads to inflammation of brain tissues, causing neuronal damage, apoptosis, and necrosis. The immune response to the virus, including the activation of microglia and release of cytokines and chemokines, further contributes to inflammation and neuronal injury. This process results in the clinical symptoms associated with encephalitis, including headache, fever, cognitive disturbances, and, in severe cases, seizures, paralysis, or coma.
Carrier Status: The primary carrier of La Crosse encephalitis is the mosquito species Aedes triseriatus. Other mosquito species, such as Aedes albopictus and Aedes japonicus, can also be vectors. It is not directly transmitted from person to person.
Mechanism: La Crosse encephalitis is caused by the La Crosse virus, a member of the Bunyaviridae family. The primary mechanism through which the virus causes disease involves infection of host cells, particularly neurons, resulting in inflammation and neuronal damage.

Molecular mechanisms include:
1. **Attachment and Entry**: The La Crosse virus attaches to host cell receptors and enters cells via endocytosis.
2. **Replication**: Once inside, the virus releases its RNA genome, which is transcribed and replicated in the host cell cytoplasm using the viral RNA-dependent RNA polymerase.
3. **Protein Synthesis**: The viral RNA serves as a template for the translation of viral proteins, including structural proteins necessary for new virions.
4. **Assembly and Release**: New viral particles are assembled and released from the host cell through budding, leading to cell lysis or apoptosis.
5. **Immune Response**: The host's immune response to the infection includes the production of cytokines and chemokines, leading to inflammation of brain tissues (encephalitis).

These molecular interactions and the immune response contribute to the symptoms and pathology of La Crosse encephalitis.
Treatment: No specific therapy is available at present for La Crosse encephalitis, and management is limited to alleviating the symptoms and balancing fluids and electrolyte levels. Intravenous ribavirin is effective against La Crosse encephalitis virus in the laboratory, and several studies in patients with severe, brain biopsy confirmed, La Crosse encephalitis are ongoing.
In a trial with 15 children being infected with La Crosse viral encephalitis were treated at certain phases with ribavirin (RBV). RBV appeared to be safe at moderate doses. At escalated doses of RBV, adverse events occurred and then the trial was discontinued. Nonetheless, this was the largest study of antiviral treatment for La Crosse encephalitis.
Compassionate Use Treatment: La Crosse encephalitis is a viral disease transmitted by mosquitoes, primarily affecting children. There are no specific antiviral treatments approved for La Crosse encephalitis. Supportive care, including hospitalization, intravenous fluids, and anticonvulsants for seizure management, is the mainstay of treatment.

For compassionate use or off-label/experimental treatments, some approaches might include the use of antiviral medications that are generally prescribed for other viral infections, although their effectiveness for La Crosse encephalitis is not well-documented. Immunoglobulin therapy or corticosteroids might also be considered in severe cases to modulate the immune response, but such treatments would be experimental and should be considered on a case-by-case basis with careful clinical judgment. Always consult a healthcare provider to explore these options thoroughly.
Lifestyle Recommendations: For La Crosse encephalitis, lifestyle recommendations to reduce the risk of infection include:

1. **Avoid Mosquito Bites:**
- Use insect repellent containing DEET, picaridin, or oil of lemon eucalyptus.
- Wear long sleeves and long pants, especially during peak mosquito activity times (dusk and dawn).
- Use mosquito netting over strollers, cribs, and other areas where infants or young children are present.

2. **Eliminate Mosquito Habitats:**
- Remove standing water around your home where mosquitoes can breed, such as in birdbaths, flowerpot saucers, and rain gutters.
- Change water in pet dishes and replace water in bird baths regularly.

3. **Control Mosquitoes Indoors:**
- Use air conditioning or ensure windows and doors are properly screened.
- Repair any holes in screens to prevent mosquitoes from entering your home.

4. **Community Measures:**
- Participate in community mosquito control programs if available.
- Support local efforts to reduce mosquito populations through public awareness and mosquito control initiatives.

These steps can help minimize exposure to the mosquito vectors that transmit La Crosse encephalitis.
Medication: La Crosse encephalitis does not have a specific antiviral medication. Treatment primarily focuses on supportive care to manage symptoms. This may include hospitalization, intravenous fluids, and medications to reduce fever, control seizures, and alleviate other symptoms. Prompt medical attention is essential for managing severe cases.
Repurposable Drugs: Currently, there are no specific antiviral drugs approved for La Crosse encephalitis. Treatment primarily focuses on supportive care. However, some repurposable drugs that have shown potential in related viral encephalitis cases include ribavirin and intravenous immunoglobulin (IVIG). Always consult with a healthcare provider for the most appropriate treatment options.
Metabolites: La Crosse encephalitis is a viral disease caused by the La Crosse virus, which is primarily transmitted through the bite of infected Aedes mosquitoes. Currently, specific metabolites related to La Crosse encephalitis infection have not been well-documented in scientific literature.
Nutraceuticals: Nutraceuticals have not been established as a specific treatment or preventive measure for La Crosse encephalitis. The disease primarily requires supportive care, and preventive measures focus on mosquito control and reducing exposure to mosquito bites. Always consult healthcare providers for personal medical advice.
Peptides: La Crosse encephalitis is typically caused by infection with the La Crosse virus, transmitted primarily through mosquito bites. Peptides and nanoparticles (abbreviated as nan) are currently being explored in various areas of medical research, but specific applications for La Crosse encephalitis might not be well-established yet. Peptides could be investigated for their potential roles in diagnostics or therapeutics, while nanoparticles might be researched for drug delivery systems or vaccine development. However, these areas are still largely experimental in the context of La Crosse encephalitis.