La Crosse encephalitis, caused by the La Crosse virus (LACV), is a rare central nervous system (CNS) infection that is predominantly seen in the basins of the Mississippi and Ohio rivers, and the name was given after the first case was confirmed in La Crosse, Wisconsin [1] [2]. Humans are infected by this virus after being bitten by Aedes triseriatus, the local forest-dwelling mosquito, and a stable animal reservoir of the virus was identified to be among chipmunks and squirrels in these areas [1] [2]. For this reason, the infection is considered to be of zoonotic nature, and the summer months are when most cases are reported [3] [4] [5]. The majority of individuals who get infected by the LACV develop an asymptomatic form of illness and rough estimates suggest that approximately 1 in 1000 patients suffers from a more severe form of illness [1] [2]. La Crosse encephalitis is predominantly diagnosed in children under 15 years of age, and the incubation period symptoms appear about 3-7 days after being bitten by an infected mosquito [1] [8]. Seizures, altered mental state, cognitive impairment, and coma are main clinical features, whereas fever headaches, vomiting, and other neurological deficits (hemiparesis, dysarthria, chorea, and aphasia) are common manifestations as well [1] [4] [5] [6]. Rapid clinical deterioration, stemming from increased intracranial pressure, cerebral herniation, respiratory insufficiency requiring intubation, and status epilepticus, is encountered in a minority of cases [1] [4] [5] [6]. It must be noted that the majority of deaths by LACV occur due to La Crosse encephalitis, indicating that early recognition is vital for preventing complications [1] [4] [5]. In addition, long-term neurological sequelae are readily observed among survivors [5].

• Fever

  Patients with the disease are given supportive treatment for the symptoms, particularly headaches, fever and seizures. [whsv.com]

  West Nile fever symptoms include: Sudden onset of high fever (usually greater than 102°F) Severe headache Nausea Vomiting Sore throat Backache Joint pain Prominent muscle aches and weakness Prolonged fatigue Rash (more commonly associated with West Nile [parkwayfamilyphysicians.com]

  Mosqutio types and their diseases ( Dengue Fever, West Nile virus,Eastern equine encephalitis, Venezuelan equine encephalitis, yellow fever, filariasis, Japanese encephalitis, Saint Louis encephalitis, Western equine encephalitis, La Crosse encephalitis [play.google.com]

  Time Course of Illness and Fever and Duration of Interventions in Patients with La Crosse Encephalitis. The duration of illness and fever and the timing of interventions are shown in Table 3. [content.nejm.org]

• Disability

  Disability adjusted life years (DALYs) were calculated to measure the productive life years lost to LACE. Approximately 13.00 DALYs were accumulated over 100.59 CLYs of study. [ncbi.nlm.nih.gov]

  In rare cases, long-term disability or death can result from La Crosse encephalitis. There is no specific treatment for LACV infection– care is based on symptoms. [mcevbd.wisc.edu]

  Cases are rarely fatal but may result in learning disabilities in recovered individuals. It has been estimated that for every symptomatic case there are 1,500 asymptomatic cases. [in.gov]

  Symptoms of severe LACV can include seizures, coma, and paralysis and in rare cases long term disability or death. Severe LACV usually occurs in young children under the age of 16. There are no specific treatments, cures or vaccines for LACV. [mosquitosquad.com]

• Asymptomatic

  Most patients are asymptomatic, but a small number progresses to severe and life-threatening encephalitis characterized by a range of neurological symptoms and fever. [symptoma.com]

  Asymptomatic infections are not uncommon, but symptoms including fever, headache, fatigue, lethargy, and nausea and vomiting often manifest five to 15 days post infection. [neha.org]

  It has been estimated that for every symptomatic case there are 1,500 asymptomatic cases. You can learn more about La Crosse encephalitis by visiting the following Web site: http://www.cdc.gov/ncidod/dvbid/arbor/lacfact.htm [in.gov]

  While infections are often asymptomatic and seldom fatal, the long-term neurologic sequelae of La Crosse encephalitis represent a significant burden. ©2016 by the North Carolina Institute of Medicine and The Duke Endowment. All rights reserved. [ncbi.nlm.nih.gov]

  While infections are often asymptomatic and seldom fatal, the long-term neurologic sequelae of La Crosse encephalitis represent a significant burden. [ncmedicaljournal.com]

• Fatigue

  Asymptomatic infections are not uncommon, but symptoms including fever, headache, fatigue, lethargy, and nausea and vomiting often manifest five to 15 days post infection. [neha.org]

  Symptoms of onset illness include fever, headache, vomiting, fatigue, and lethargy. Most commonly, severe cases of LACV occur in children under the age of 16. In cases of children with LACV, the patient usually suffer from seizures as well. [alabamapublichealth.gov]

  Symptoms for La Crosse encephalitis include fever, fatigue, headache and vomiting with nausea initially. Should the disease progress, LACV may cause an inflammation of the brain, which can result in seizures. [mosquitonix.com]

  LACV disease is usually characterized by fever (usually lasting 2-3 days), headache, nausea, vomiting, fatigue (tiredness), and lethargy (reduced activity or alertness). [cdc.gov]

  The CDC reports symptoms La Crosse Encephalitis can include fever, headache, nausea, vomiting, fatigue and lethargy. Severe neuroinvasive illness can occur and does most frequently in children younger than 16 years old. [twin-cities.mosquitosquad.com]

• Hunting

  Hunt;Manuel Caceres;Raheel Khan;Mouna Chebib;Sasidharan Taravath;Linda Minnich;Roxane Carr;Christine Welch;Richard Whitley; Checking for direct PDF access through Ovid Abstract La Crosse viral encephalitis (LACVE) is associated with residual epilepsy [doi.org]

  Keywords Arboviral encephalitis La Crosse virus LACVE Meningoencephalitis Mosquito To read this article in full you will need to make a payment References Hunt W.G. McJunkin J.E. [amjmed.com]

  Clements-Hunt News All news » News releases Statements Notes for media Commentaries Events Feature stories Speeches Spotlight Headlines » Spotlight » WHO/Rada Akbar Ten threats to global health in 2019 Emergencies Focus on » Bangladesh Rohingya Democratic [who.int]

  It is mainly a rural disease associated with the risk factors of farming, hunting, and camping, because these activities bring humans into close contact with the rodent reservoirs. [infectiousdiseaseadvisor.com]

• Dyspnea

  This phase usually progresses rapidly to severe respiratory disease characterized by non-productive cough and dyspnea. This bilateral pulmonary edema is usually visible in chest X-rays. [infectiousdiseaseadvisor.com]

• Nausea

  The virus for La Crosse encephalitis is carried by mosquitos and can cause symptoms of headaches, nausea and eye pain. The doctor said that 90 percent of the time, people who are bitten by an infected mosquito never get sick. [10tv.com]

  These symptoms include fever, headache, nausea and vomiting. There may be neurologic symptoms such as confusion or loss of balance and in more severe cases, convulsions or coma may occur. [smokymountainnews.com]

  Typically flu-like, including headache, fever, muscle ache, and nausea. Severe symptoms include encephalitis and/or meningitis. Severe symptoms also include seizures, paralysis, and coma, with neurological sequelae in survivors. [extension.entm.purdue.edu]

  With flu-like symptoms that can include headache, body aches, nausea, joint pains, vomiting or diarrhea, West Nile Virus can be brutal, but only about 20-30% of those infected will show any symptoms. [twin-cities.mosquitosquad.com]

• Neck Pain

  pain and drowsiness and nausea and fever (`phrenitis' is no longer in scientific use) inflammation, redness, rubor - a response of body tissues to injury or irritation; characterized by pain and swelling and redness and heat West Nile encephalitis - [thefreedictionary.com]

• Suggestibility

  These findings suggest that susceptibility and complications associated with this disease may have an immunogenetic component. [ncbi.nlm.nih.gov]

• Seizure

  All patients presented with fever and disorientation; 6 of the 9 (66%) presented with seizures. PLEDS localized to the temporal lobe in 7 patients (77%). [ncbi.nlm.nih.gov]

  Seizures were the presenting finding in 58 of the patients (46 percent). Of those with seizures, 14 (24 percent) had status epilepticus, and 36 (62 percent) had seizures with a focal component. [content.nejm.org]

  Lethargy, behavioral changes, and/or brief seizures may occur on days 3 and 4, followed by improvement over a 7- to 8-day period. [pediatrics.aappublications.org]

• Headache

  The virus for La Crosse encephalitis is carried by mosquitos and can cause symptoms of headaches, nausea and eye pain. The doctor said that 90 percent of the time, people who are bitten by an infected mosquito never get sick. [10tv.com]

  Estep experienced severe headaches after his bite from an infected mosquito. When his mother took him to the hospital, doctors tested him. [wsaz.com]

  Patients with the disease are given supportive treatment for the symptoms, particularly headaches, fever and seizures. [whsv.com]

  The less common (10% to 20%), more severe presentation includes abrupt fever and headache, disorientation and seizures, occurring within the first 8 to 24 hours of symptomatology, sometimes progressing to deep coma, associated in rare cases with cerebral [pediatrics.aappublications.org]

• Lethargy

  While most people who become infected have no symptoms, those who do become ill may have fever, headache, vomiting and lethargy (tiredness). Severe cases develop encephalitis accompanied by seizures. [rarediseases.info.nih.gov]

  Typically, LAC encephalitis initially presents as a nonspecific illness with fever, headache, nausea, vomiting, and lethargy. [valentbiosciences.com]

  Asymptomatic infections are not uncommon, but symptoms including fever, headache, fatigue, lethargy, and nausea and vomiting often manifest five to 15 days post infection. [neha.org]

  LAC encephalitis initially presents as a nonspecific summertime illness with fever, headache, nausea, vomiting and lethargy. [medicinenet.com]

• Irritability

  Do not apply insect repellent to a child’s hands, eyes, mouth, cuts, or irritated skin. Adults: Spray insect repellent onto your hands and then apply to a child’s face. Tips for Everyone Always follow the product label instructions. [cdc.gov]

  Symptoms of the infection, which causes irritation of the brain, include headaches, fever, nausea, vomiting, drowsiness and disorientation. Severe cases my include seizures, coma or even death. [wvlt.tv]

  The virus, which occurs more frequently in children 16 and younger, irritates the brain; symptoms can include headache, fever, nausea, vomiting, drowsiness and dizziness, and in severe cases, seizures or coma. [eu.knoxnews.com]

  […] encephalitis - inflammation of the brain usually caused by a virus; symptoms include headache and neck pain and drowsiness and nausea and fever (`phrenitis' is no longer in scientific use) inflammation, redness, rubor - a response of body tissues to injury or irritation [thefreedictionary.com]

• Tremor

  In more severe cases, convulsions, tremors and coma can occur. Children under 16 years of age and the elderly are the most susceptible to the disease. There are, on average, 70 cases of La Crosse virus annually in America. [infectioncontroltoday.com]

  The neuro-invasive disease is characterized by neurological symptoms, such as seizures, tremors, and convulsions. Meningitis, encephalitis, flaccid paralysis, and coma can also occur. HCPS: The incubation period for HCPS ranges from 9 to 33 days. [infectiousdiseaseadvisor.com]

  However, some people may develop more severe symptoms including headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, seizures, and/or paralysis. The overall death rate is 5 to 15 percent. Who is most at risk for St. [wvdhhr.org]

  • Aphasia • Ataxia • Weakness: Hemiparesis with hyperactive tendon reflexes • Cranial nerve deficits • Involantary movements- tremors, myoclonic jerks • Seizures >50% patients • SIADH 22. [slideshare.net]

The signs and symptoms of La Crosse encephalitis point to a nonspecific infection of the CNS and the differential diagnosis is often turned toward more common causes of viral encephalitis, such as herpes simplex virus (HSV) and enteroviruses [1] [5]. However, the specific geographical location is of crucial importance for including LACV as a possible cause. Thus, a detailed patient history must cover recent traveling to endemic areas of the United States (or if patients are living in these areas) and note whether mosquito bites occurred. The physical examination, if conducted properly, can immediately point to a CNS infection, in which case both laboratory and microbiological studies should be employed. A lumbar puncture will show mild lymphocytic (or sometimes neutrophilic) pleocytosis, and increased protein levels are observed in up to 30% of patients, while leukocytosis in a complete blood count (CBC) is also seen [1] [2] [5]. A definite diagnosis of La Crosse encephalitis is made after conducting one of the two microbiological procedures - serology or polymerase chain reaction (PCR) [6] [7] [8]. Identification of immunoglobulin (Ig) M or high titer IgG antibodies is a reliable and effective method, whereas detection of viral deoxyribonucleic acid (DNA) in the cerebrospinal fluid (CSF) through molecular methods, such as PCR and reverse transcriptase-PCR has increased the overall efficacy in identifying LACV in human tissue [1] [5] [6] [7] [8].

• Hyponatremia

  Hyponatremia and increasing body temperature may be related to clinical deterioration. [ncbi.nlm.nih.gov]

  Hyponatremia is a common complication and a risk factor for seizures and clinical deterioration. [pediatricneurologybriefs.com]

  Fever, headache, and hyponatremia were seen in the majority, while mental status changes occurred in 5 patients and seizures in 2 patients. [amjmed.com]

There is no specific treatment for LaCrosse encephalitis. Antibiotics are not effective against viruses, and no effective anti-viral drugs have been discovered. Care of patients centers on treatment of symptoms and complications. [web.archive.org]

Nevertheless, valuable pharmacokinetic (PK) and safety data were obtained at moderate dose, with potential treatment implications for other indications. [ncbi.nlm.nih.gov]

Aedes japonicus, and Aedes triseriatus in Tennessee. ( 26375904 ) 2015 5 La Crosse encephalitis surveillance using single versus paired serologic testing. ( 21848528 ) Murphree R....Jones T.F. 2012 6 Safety and pharmacokinetics of ribavirin for the treatment [malacards.org]

Treatment There is no specific treatment for La Crosse encephalitis. No anti-viral drugs are available at this time, and antibiotics are not effective against viruses. [whsv.com]

(Outcomes/Resolutions) The prognosis of La Crosse Encephalitis is dependent upon the severity of the signs and symptoms and associated complications, if any Individuals with mild conditions have better prognosis than those with severe symptoms and complications [dovemed.com]

Less than 1% of cases result in mortality. [5] Complications Common complications of La Crosse encephalitis virus include: Recurring seizures Coma Loss of basic motor skills Loss of coordination Prognosis Prognosis for La Crosse encephalitis virus is [wikidoc.org]

In addition, even experienced physicians often are uncertain about the cause, appropriate therapy, and prognosis. [pedsinreview.aappublications.org]

Prognosis • The mortality rate varies with etiology, and epidemics due to the same virus vary in severity in different years. • Bad: Eastern equine encephalitis virus infection, nearly 80% of survivors have severe neurological sequelae. • Not so Bad: [slideshare.net]

Studies comparing LAC cases with non-LAC (no etiologic diagnosis) central nervous system infections have yielded no statistical significance in signs and symptoms or laboratory values. [ncbi.nlm.nih.gov]

It has long been suspected that LAC has a broader distribution and a higher incidence in the Eastern United States than is reported, but is under-reported because the etiologic agent is often not specifically identified. [nemosquito.org]

LaCrosse Encephalitis Facts & Information: CLINICAL FEATURES: Frank encephalitis progressing to seizures, coma; majority of infections are subclinical or result in mild illness ETIOLOGIC AGENT : La Crosse virus - California serogroup virus in the family [mosquitocontrol.org]

Epidemiology of California encephalitis in Minnesota. [genome.jp]

Epidemiology Epidemiology & Geographic Distribution In the United States, approximately 80-100 La Crosse encephalitis virus (LACV) neuroinvasive disease cases are reported each year. [usaebn.org]

Please visit the Centers for Disease Control and Prevention (CDC) page for details on: Symptoms Diagnosis Treatment Statistics and epidemiology Guidance for health practitioners [mcevbd.wisc.edu]

Epidemiology and Ecology, Vol I. Boca Raton, FL, CRC Press, 1988, pp 1 27 - 152. [journals.sagepub.com]

Useful For Suggests clinical disorders or settings where the test may be helpful Aiding the diagnosis of California (La Crosse) encephalitis Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a [mayocliniclabs.com]

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test California (La Crosse) virus is a member of the Bunyaviridae family and it is one of the arthropod-borne encephalitides. [mayomedicallaboratories.com]

Pathophysiology La Crosse virus is transmitted subcutaneously through penetration of the skin by a feeding mosquito. Two surface glycoproteins subtypes are involved in the transmission of the virus. [ncbi.nlm.nih.gov]

The La Crosse virus is the principal member of the California encephalitis serogroup, which contains genetically similar viruses such as California encephalitis virus. [5] Pathophysiology La Crosse encephalitis virus is usually transmitted via mosquitos [wikidoc.org]

Preventing LACV in the Carolinas Limiting your exposure to mosquitoes and mosquito bites is the best method of preventing LACV. Since people spend a majority of their outdoor living in their own yard, it’s a great place to start. [mosquitosquad.com]

In the context of LACE, disease prevention presently relies on personal protection efforts to prevent mosquito bites. [ncmedicaljournal.com]

While it's not 100 percent preventable, as someone who has experienced the disease herself, she said, "do what you can to try" to prevent your child from going through the same thing. [newsweek.com]

How can LaCrosse encephalitis be prevented? There is no vaccine for LaCrosse encephalitis. Prevention centers on public health action to control mosquitoes and on individual action to avoid mosquito bites. [web.archive.org]

Tips on preventing mosquito bites. Questions about illnesses spread by mosquitoes? Contact us! Phone: 608-267-9003 | Fax: 608-261-4976 Last Revised: June 15, 2022 [dhs.wisconsin.gov]

1. McJunkin JE, de los Reyes EC, Irazuzta JE, et al. La Crosse encephalitis in children. N Engl J Med. 2001;344(11):801-807.
2. Davis LE, Beckham JD, Tyler KL. North American encephalitic arboviruses. Neurol Clin. 2008;26(3):727-ix.
3. Lambert AJ, Fryxell RT, Freyman K, et al. Comparative Sequence Analyses of La Crosse Virus Strain Isolated from Patient with Fatal Encephalitis, Tennessee, USA . Emerg Infect Dis. 2015;21(5):833-836.
4. Haddow AD, Odoi A. The Incidence Risk, Clustering, and Clinical Presentation of La Crosse Virus Infections in the Eastern United States, 2003–2007. Rénia L, ed. PLoS One. 2009;4(7):e6145.
5. Mandell GL, Bennett JE, Dolin R. Mandel, Douglas and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, Pennsylvania: Churchill Livingstone; 2015.
6. Jones TF, Erwin PC, Craig AS, et al. Serological survey and active surveillance for La Crosse virus infections among children in Tennessee. Clin Infect Dis. 2000;31:1284-1287.
7. Lambert AJ, Nasci RS, Cropp BC, et al. Nucleic Acid Amplification Assays for Detection of La Crosse Virus RNA. J Clin Microbiol. 2005;43(4):1885-1889.
8. Murray PR, Rosenthal KS, Pfaller MA. Medical Microbiology. Seventh edition. Philadelphia: Elsevier/Saunders; 2013.