Skip to content
How It Works
Explore
Resources Ask a Question
Who It's For
Patients
Decode results, prep for appointments, weigh options.
Caregivers & advocates
Carry the research load for someone you love.
Providers & clinicians
Resources for patients in your practice.
Log In Ask a Question
PubMed This is a summary of 49 peer-reviewed journal articles Updated
Pediatrics

Understanding La Crosse Encephalitis: An Overview for Parents

At a Glance

La Crosse encephalitis is a serious but highly survivable mosquito-borne viral infection that causes brain inflammation in children. While there is no specific cure, hospitals provide supportive care to manage symptoms like fever and seizures while the child's brain naturally heals.

Finding out your child has La Crosse encephalitis, caused by the La Crosse virus (LACV), can be an overwhelming experience. It often appears suddenly, turning a typical childhood illness into a serious neurological event that requires hospitalization [1][2]. While the symptoms are frightening, understanding the nature of this virus and the recovery process can help you navigate the days ahead.

What is La Crosse Encephalitis?

La Crosse encephalitis is a viral infection that causes inflammation of the brain (encephalitis). In the United States, it is the most common cause of pediatric neuroinvasive arboviral disease—a term for viruses spread by insects that attack the central nervous system [3][4].

The virus is primarily found in two regions:

  • Appalachia: Including West Virginia, East Tennessee, Western North Carolina, and Ohio [5][6].
  • Upper Midwest: Including states like Wisconsin and Minnesota [6].

How Children Get the Virus

The virus is transmitted through the bite of an infected mosquito, specifically the Aedes triseriatus (often called the Eastern Tree-hole Mosquito) [7][8]. These mosquitoes typically breed in stagnant water found in tree holes, discarded tires, or containers in shaded, wooded areas [9]. You can learn more about how to protect your family in our section on Prevention, Mosquito Control, and Source Reduction.

Once the virus enters the body, it must cross the blood-brain barrier (the protective layer that prevents toxins and pathogens from entering the brain) to cause encephalitis [10][11]. Children are more susceptible to this “neuroinvasion” than adults, which is why the disease is seen almost exclusively in pediatric patients [12][1].

Stabilizing Facts for Parents

When a child is diagnosed with a brain infection, panic is a natural response. However, there are several key facts that can provide perspective:

  • High Survival Rate: The vast majority of children survive LACV. The mortality (death) rate is very low, estimated at approximately 1% to 1.4% [4][1]. However, while survival is highly likely, a significant portion of pediatric LACV survivors experience long-term neurological sequelae, such as recurrent seizures, cognitive deficits, or behavioral changes that require long-term follow-up care.
  • Primary Treatment: While there is no specific “cure” or antiviral drug for LACV, hospitals provide supportive care [13]. This involves proactive medical management: using IV fluids to keep the child hydrated, medications to control or prevent seizures, and therapies to monitor and reduce brain swelling [14][15]. Read more in Hospital Treatment and Supportive Care.
  • Natural Recovery: Most children recover from the acute phase of the illness within a few weeks, though the brain requires significant time to heal completely [2].

What to Expect During Recovery

The acute stage of LACV often involves fever, headache, vomiting, and seizures [1][2]. For more details on the emergency phase, see Symptoms, Progression, and Warning Signs. As the inflammation subsides, the focus shifts to long-term monitoring.

  1. Seizure Management: Because LACV causes inflammation in the brain’s gray matter, some children may experience an increased risk of epilepsy (recurrent seizures) after the initial infection [16].
  2. Cognitive and Behavioral Changes: Some survivors may experience “sequelae”—long-term effects such as trouble concentrating, irritability, or changes in school performance [12][17].
  3. Follow-up Care: It is standard practice for children who have had LACV to have scheduled visits with a pediatric neurologist to monitor brain health and development [12]. We detail this further in Life After the Hospital.

Understanding that these challenges are known and manageable parts of the recovery process can help your family move forward with a plan for support and healing.

In this guide

5 chapters

01

Symptoms, Progression, and Warning Signs of La Crosse Encephalitis

Learn the symptoms and warning signs of La Crosse encephalitis in children. Understand the rapid progression from fever to emergencies like seizures.

02

Diagnosis, Testing, and Recognizing Look-Alikes

Learn how doctors diagnose La Crosse encephalitis (LACV). Understand antibody tests, MRI brain imaging, EEG results, and how it is distinguished from HSV.

03

Hospital Treatment and Supportive Care for La Crosse Encephalitis

Discover hospital treatments for La Crosse encephalitis in children. Learn how ICU doctors manage brain swelling, control seizures, and provide supportive care.

04

Life After the Hospital: Survivorship, Cognitive Monitoring, and Epilepsy Risk

Learn about La Crosse encephalitis (LACV) recovery. Understand the long-term risk for epilepsy, cognitive changes, and how to advocate for school support.

05

Prevention, Mosquito Control, and Source Reduction

Learn how to prevent La Crosse encephalitis (LACV) by managing the Eastern Tree-hole mosquito. Discover effective source reduction and repellent strategies.

Common questions in this guide

How do children get La Crosse encephalitis?
Children typically contract the virus from the bite of an infected Aedes triseriatus mosquito, commonly known as the tree-hole mosquito. These mosquitoes usually breed in stagnant water found in shaded, wooded areas, such as tree holes or discarded tires.
What is the survival rate for La Crosse encephalitis in children?
The survival rate for pediatric La Crosse encephalitis is very high, with a mortality rate estimated at just 1% to 1.4%. Most children survive the acute infection, though some may require long-term care for lingering neurological effects.
Is there a cure or specific medication for La Crosse virus?
There is no specific antiviral cure for La Crosse encephalitis. Treatment involves supportive care in a hospital setting, which includes administering IV fluids, managing brain swelling, and using medications to control or prevent seizures.
Will my child have long-term side effects from La Crosse encephalitis?
While most children recover, some survivors experience long-term neurological effects known as sequelae. These can include recurrent seizures (epilepsy), difficulty concentrating, or behavioral changes that require ongoing monitoring by a pediatric neurologist.
What are the early signs of La Crosse encephalitis?
The acute stage of the illness often begins suddenly with a fever, severe headache, vomiting, and sometimes seizures. Because the virus causes brain inflammation, these symptoms require prompt medical evaluation and hospitalization.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.What specific neurological signs (like seizure activity or cerebral edema) were observed during my child's acute phase?
  2. 2.How do we distinguish between normal recovery and the potential development of post-infection epilepsy?
  3. 3.Does our hospital have a protocol for long-term neurobehavioral or cognitive follow-up for children who have had LACV?
  4. 4.Are there specific physical or cognitive activities my child should avoid during their recovery period?
  5. 5.What are the signs of a 'breakthrough' seizure I should look for at home?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (17)
  1. 1

    Endemic La Crosse Virus Neuroinvasive Disease in North Carolina Residents: 2000-2020.

    Davis J, Atkins C, Doyle M, et al.

    North Carolina medical journal 2024; (85(4)):289-295 doi:10.18043/001c.118585.

    PMID: 39466102
  2. 2

    Double Crossed: A Case of La Crosse Encephalitis.

    Ding A, Shen B, Elliott S, et al.

    Rhode Island medical journal (2013) 2020; (103(3)):59-62.

    PMID: 32236166
  3. 3

    West Nile Virus and Other Nationally Notifiable Arboviral Diseases - United States, 2023.

    Padda H, Jacobs D, Gould CV, et al.

    MMWR. Morbidity and mortality weekly report 2025; (74(21)):358-364 doi:10.15585/mmwr.mm7421a1.

    PMID: 40504766
  4. 4

    La Crosse Virus Disease in the United States, 2003-2019.

    Vahey GM, Lindsey NP, Staples JE, Hills SL

    The American journal of tropical medicine and hygiene 2021; (105(3)):807-812.

    PMID: 34280142
  5. 5

    Geographically persistent clusters of La Crosse virus disease in the Appalachian region of the United States from 2003 to 2021.

    Day CA, Odoi A, Trout Fryxell R

    PLoS neglected tropical diseases 2023; (17(1)):e0011065 doi:10.1371/journal.pntd.0011065.

    PMID: 36656896
  6. 6

    Persistent spatial clustering and predictors of pediatric La Crosse virus neuroinvasive disease risk in eastern Tennessee and western North Carolina, 2003-2020.

    Day CA, Odoi AO, Moncayo A, et al.

    PLoS neglected tropical diseases 2024; (18(6)):e0012186 doi:10.1371/journal.pntd.0012186.

    PMID: 38843214
  7. 7

    Characterizing oogenesis and programmed cell death in the eastern tree hole mosquito Aedes (Protomacleaya) triseriatus.

    Airs PM, Nazarchyk MJ, Tucker BJ, Bartholomay LC

    Frontiers in insect science 2022; (2()):1073308 doi:10.3389/finsc.2022.1073308.

    PMID: 38468807
  8. 8

    La Crosse Virus: A Comprehensive Review of Its Emerging Public Health Importance.

    Feng S, Feng X, Zhu W, et al.

    Viral immunology 2025; (38(4)):137-147 doi:10.1089/vim.2024.0088.

    PMID: 40274395
  9. 9

    Ohio Amish may be disproportionately at risk for La Crosse virus infection.

    Chaney ME, Bergey CM

    medRxiv : the preprint server for health sciences 2026; doi:10.64898/2026.01.14.26344083.

    PMID: 41646763
  10. 10

    Age influences susceptibility of brain capillary endothelial cells to La Crosse virus infection and cell death.

    Basu R, Nair V, Winkler CW, et al.

    Journal of neuroinflammation 2021; (18(1)):125 doi:10.1186/s12974-021-02173-4.

    PMID: 34082753
  11. 11

    Identification of age-specific gene regulators of La Crosse virus neuroinvasion and pathogenesis.

    Basu R, Ganesan S, Winkler CW, et al.

    Nature communications 2023; (14(1)):2836 doi:10.1038/s41467-023-37833-x.

    PMID: 37202395
  12. 12

    La Crosse virus encephalitis in children.

    Ouellette CP

    Current opinion in infectious diseases 2024; (37(5)):419-424 doi:10.1097/QCO.0000000000001042.

    PMID: 39079177
  13. 13

    A cap-dependent endonuclease inhibitor acts as a potent antiviral agent against La Crosse virus infection.

    Konishi K, Taoda Y, Igarashi M, et al.

    Antimicrobial agents and chemotherapy 2025; (69(9)):e0018625 doi:10.1128/aac.00186-25.

    PMID: 40698821
  14. 14

    The La Crosse virus class II fusion glycoprotein ij loop contributes to infectivity and replication in vitro and in vivo.

    Thannickal SA, Spector SN, Stapleford KA

    Journal of virology 2023; (97(8)):e0081923 doi:10.1128/jvi.00819-23.

    PMID: 37578236
  15. 15

    Structure, function, and evolution of the Orthobunyavirus membrane fusion glycoprotein.

    Hellert J, Aebischer A, Haouz A, et al.

    Cell reports 2023; (42(3)):112142 doi:10.1016/j.celrep.2023.112142.

    PMID: 36827185
  16. 16

    La Crosse Virus Neuroinvasive Disease in Children: A Contemporary Analysis of Clinical/Neurobehavioral Outcomes and Predictors of Disease Severity.

    Boutzoukas AE, Freedman DA, Koterba C, et al.

    Clinical infectious diseases : an official publication of the Infectious Diseases Society of America 2023; (76(3)):e1114-e1122 doi:10.1093/cid/ciac403.

    PMID: 35607778
  17. 17

    Retinoic acid-induced differentiation and oxidative stress inhibitors increase resistance of human neuroblastoma cells to La Crosse virus-induced cell death.

    Policastro PF, Schneider CA, Winkler CW, et al.

    Journal of virology 2024; (98(11)):e0030024 doi:10.1128/jvi.00300-24.

    PMID: 39382324

This page provides an overview of La Crosse encephalitis for educational purposes. Always consult a pediatric neurologist or healthcare provider for specific medical advice regarding your child's symptoms and long-term recovery.

Get notified when new evidence is published on La Crosse encephalitis.

We monitor PubMed for new peer-reviewed studies on this topic and email a short summary when something meaningful changes.