West Nile encephalitis (WNE) is one of the illnesses caused by West Nile virus (WNV) infection. Most individuals infected with WNV are asymptomatic, some develop West Nile fever, and a small percentage develop neuroinvasive disease. WNV is transmitted to humans mainly via mosquito bites. The incubation period ranges from 2 days to 2 weeks [1]. WNE can present in a number of ways, albeit similar to other types of viral encephalitis. Patients usually have a fever, headache, and altered mental status.

Initial symptoms and signs of illness may include myalgia, arthralgia, or pharyngitis and are often nonspecific. Those at the extremes of age have more pronounced symptoms. Aseptic meningitis may occur simultaneously with encephalitis, resulting in signs of meningism. The severity of illness is proportional to the extent of viral invasion. Changes in the mental status range from acute confusion to coma.

Gastrointestinal upset (nausea and vomiting) is common. Gait instability, coarse tremor, and bulbar palsy have been described [2]. Less frequently reported are seizures and cerebral edema [3]. Parkinsonism, extrapyramidal manifestations, myoclonus, and muscle weakness mimicking lower motor neuron lesions, also form part of the clinical picture [4].

WNE could present with acute flaccid paralysis, which is also directly caused by WNV infection. The presence of muscle weakness distinguishes WNE from other encephalitides. Facial nerve palsies present acutely or over the course of a few weeks [5]. Elderly individuals are at an increased risk [6].

Further presenting features of WNE are ophthalmologic manifestations, lymphadenopathy (especially of the submental nodes), and a maculopapular rash on the trunk [5].

• Fever

  fever, WN - West Nile fever, West Nile fever (diagnosis), West Nile virus infection, West Nile fever NOS, West Nile Fever [Disease/Finding], west nile fever, West Nile fever (disorder), West nile virus infection, West Nile; fever, fever; West Nile, West [fpnotebook.com]

  We report the case of a 46-year-old woman who presented with fever, altered mental status, and maculopapular rash, who was diagnosed with locally acquired WNV encephalitis. [ncbi.nlm.nih.gov]

  (inanition) (of unknown origin) (persistent) (with chills) (with rigor) R50.9 ICD-10-CM Diagnosis Code R50.9 Fever, unspecified 2016 2017 2018 2019 Billable/Specific Code Applicable To Fever NOS Fever of unknown origin [FUO] Fever with chills Fever with [icd10data.com]

• Fatigue

  Localized Stage (early) Early symptoms of Lyme disease include fever, fatigue, and muscle and joint aches, which can also be associated with a variety of other illnesses. [navicenthealth.org]

  The most common symptom observed in these patients was fatigue (25.93%). Other symptoms included dizziness (7.4%), decreased sense of hearing (7.4%) and decreased sense of smell (7.4%). Reduced power in limbs was found in 33.33% of the cases. [ncbi.nlm.nih.gov]

  Supportive therapy Respiratory support; airway management Increased fluid intake As tolerated Rest periods when fatigued Antipyretics such as acetaminophen Interferon alfa-2b Nursing Considerations-Nursing Diagnoses Acute pain Decreased cardiac output [quizlet.com]

  Although fatigue may occur after resolution of other viral illnesses, the frequency and severity with which WNV-associated fatigue is reported is impressive. [academic.oup.com]

• High Fever

  See a doctor if you develop symptoms such as high fever, confusion, muscle weakness, severe headache, or stiff neck. Spread West Nile virus is spread to people and animals through the bite of infected mosquitoes. [bchu.org]

  This illness can cause confusion, a high fever, and a severe headache. Other symptoms include nausea, vomiting, and a stiff neck and back. West Nile virus is not spread by touching a person who has the virus. [myhealth.alberta.ca]

  More severe symptoms may include: headache high fever neck stiffness disorientation coma tremors convulsions muscle weakness paralysis In very rare cases, severe illness may cause death. [yavapai.us]

  Symptoms of severe illness include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. [cdc.gov]

• Chills

  (with rigor) R50.9 ICD-10-CM Diagnosis Code R50.9 Fever, unspecified 2016 2017 2018 2019 Billable/Specific Code Applicable To Fever NOS Fever of unknown origin [FUO] Fever with chills Fever with rigors Hyperpyrexia NOS Persistent fever Pyrexia NOS West [icd10data.com]

  Early symptoms are nonspecific and include fever, chills, malaise, headache, ocular pain or photophobia, myalgia, and occasionally a maculopapular rash (more common in children) and gastrointestinal upset. [medical-dictionary.thefreedictionary.com]

  Photo Credit Dolly Faibyshev for The New York Times Work Out and Chill? Cool temperature workouts may be the answer for those who want to exercise without becoming a hot mess. [nytimes.com]

  When symptoms develop, West Nile virus infection typically begins with the abrupt onset of fever, chills, muscle aches, headache, and flu-like symptoms. Headache is particularly common and may be severe. [emedicinehealth.com]

• Rigor

  R50.9 ICD-10-CM Diagnosis Code R50.9 Fever, unspecified 2016 2017 2018 2019 Billable/Specific Code Applicable To Fever NOS Fever of unknown origin [FUO] Fever with chills Fever with rigors Hyperpyrexia NOS Persistent fever Pyrexia NOS West Nile (viral [icd10data.com]

  However, even with rigorous surveillance, spraying, and larvaciding, the virus may still infect people. What About “Larvicides” and “Adulticides”? Larvicides are products used to kill immature mosquitoes. [onhealth.com]

• Vomiting

  A 57-year-old Caucasian woman presented with fever, dizziness, balance difficulties, vomiting, dancing eye, altered speech, tremor, generalized myoclonus and failure to rise or stand. [ncbi.nlm.nih.gov]

  Other symptoms include nausea, vomiting, and a stiff neck and back. West Nile virus is not spread by touching a person who has the virus. Almost all cases are from mosquito bites. Most people with this illness get better after treatment. [myhealth.alberta.ca]

  Gastrointestinal upset (nausea and vomiting) is common. Gait instability, coarse tremor, and bulbar palsy have been described. Less frequently reported are seizures and cerebral edema. [symptoma.com]

  Early signs of west nile include fever, weakness, nausea and vomiting. Doctors recommend getting help if symptoms last more than 3-4 days. Only about one in 150 people infected with west nile ever develop severe symptoms. [wkyt.com]

  About 1 in 5 people who are infected develop a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea, or rash. [cdc.gov]

• Nausea

  Gastrointestinal upset (nausea and vomiting) is common. Gait instability, coarse tremor, and bulbar palsy have been described. Less frequently reported are seizures and cerebral edema. [symptoma.com]

  Early signs of west nile include fever, weakness, nausea and vomiting. Doctors recommend getting help if symptoms last more than 3-4 days. Only about one in 150 people infected with west nile ever develop severe symptoms. [wkyt.com]

  Signs and symptoms include the sudden onset of drowsiness, headache and nausea due to encephalitis, pain in the abdomen, a rash, and swollen glands (lymphadenopathy). These features are usually but not always mild. [medicinenet.com]

  Other symptoms include nausea, vomiting, and a stiff neck and back. West Nile virus is not spread by touching a person who has the virus. Almost all cases are from mosquito bites. Most people with this illness get better after treatment. [myhealth.alberta.ca]

  In adults and older children, symptoms include: fever drowsiness bad headache and stiff neck nausea muscle tremors dizziness. In young children the symptoms include: fever floppiness irritability drowsiness fits. [ww2.health.wa.gov.au]

• Hypertension

  People with certain medical conditions, such as cancer, diabetes, hypertension, kidney disease, and people who have received organ transplants, are also at greater risk. Recovery from severe illness might take several weeks or months. [cdc.gov]

  Other chronic medical problems included a history of prostate cancer in remission, dyslipidemia, and hypertension. He also had a history of “visual seizures” for which he was taking daily antiepileptic medication. [hindawi.com]

  Certain diseases, such as cancer, diabetes, hypertension and kidney disease, increase your risk. So does receiving an organ transplant. [mayoclinic.org]

• Myalgia

  Initial symptoms and signs of illness may include myalgia, arthralgia, or pharyngitis and are often nonspecific. Those at the extremes of age have more pronounced symptoms. [symptoma.com]

  […] arboviral infection caused by a virus of the Flaviviridae family transmitted by an infected mosquito, that is asymptomatic in the majority of cases but that can present in rare occasions with mild flulike symptoms such as low-grade fever, arthralgia, myalgia [orpha.net]

  Design/Methods: Case report Results: A 49-year-old woman with a history of Rheumatoid Arthritis, treated with methotrexate and biannual rituximab infusions, presented with fever, myalgia, weakness, and increasing confusion over 5 days. [n.neurology.org]

  Early symptoms are nonspecific and include fever, chills, malaise, headache, ocular pain or photophobia, myalgia, and occasionally a maculopapular rash (more common in children) and gastrointestinal upset. [medical-dictionary.thefreedictionary.com]

  It is estimated that about 20% of those who become infected will develop West Nile fever with mild symptoms including headache, myalgia, and occasionally a skin rash on the trunk of the body. [mayomedicallaboratories.com]

• Photophobia

  Early symptoms are nonspecific and include fever, chills, malaise, headache, ocular pain or photophobia, myalgia, and occasionally a maculopapular rash (more common in children) and gastrointestinal upset. [medical-dictionary.thefreedictionary.com]

  There was no evidence of tongue biting, urinary incontinence, photophobia, or nuchal rigidity. Muscle strength, tone, and deep tendon reflexes were normal and symmetric. Babinski signs were absent. Sensory examination was normal. [hindawi.com]

  The signs and symptoms of WNE may include: Fever, headache Nausea and vomiting Mental changes such as confusion, hallucination, or decreased consciousness Sensitivity to light (photophobia) Stiff neck (nuchal rigidity) Lesser known symptoms also include [dovemed.com]

  A meningeal-type infection may manifest as typical meningeal symptoms (eg, neck stiffness, photophobia, headache). [13, 20] Encephalitis may be more varied, possibly featuring mental status changes, confusion, lethargy, seizures, local paresthesia, and [emedicine.medscape.com]

• Eye Pain

  […] impairment Seizures Bronchial pneumonia Myocarditis Pancreatitis Hepatitis Death Headache Myalgia Fever Fatigue Neck stiffness Possible recent exposure to bodies of water or to dead birds Recent mosquito bites Decreased appetite Nausea Vomiting Diarrhea Eye [quizlet.com]

  The symptoms of West Nile fever include: Fever Headache Fatigue Skin rash on the trunk of the body (in some cases but not in others) Swollen lymph glands (in some cases but not in others) Eye pain (in some cases but not in others) In one in every 150 [webmd.com]

• Diplopia

  […] patients 23 64 59 16 162 General Headache 48% 27% 47% 94% 44% Altered mental status 74% 75% 46% 56% 62% Weakness 48% 41% 56% 47% 48% Central Nervous System Dysfunction Facial palsy 17% 11% — — 13% Dysphagia — 34% — 25% 33% Dysarthria — 17% 8% — 13% Diplopia [clevelandclinicmeded.com]

• Skin Rash

  Symptoms are flu-like and may include fever, headache, body aches, and/or a skin rash. The elderly and people with weak immune systems are more likely to have severe cases. [bchu.org]

  Human infection causes an illness marked by fever, headache, muscle ache, skin rash, and sometimes encephalitis or meningitis. Definition (CSP) transmitted by Culex spp mosquitos; agent of emerging disease in North America. [fpnotebook.com]

  Mild symptoms may include: fever head and body aches skin rash swollen lymph glands Less than 1 percent of the population bit by an infected mosquito is likely to become severely ill. [yavapai.us]

• Headache

  A 58-yr-old Korean man was admitted with headache and cognitive dysfunction. The patient had been on a business trip in Guinea. Cerebrospinal fluid (CSF) showed pleocytosis. [ncbi.nlm.nih.gov]

  Symptoms are flu-like and may include fever, headache, body aches, and/or a skin rash. The elderly and people with weak immune systems are more likely to have severe cases. [bchu.org]

  Common clinical features include HEADACHE; FEVER; maculopapular rash; gastrointestinal symptoms; and lymphadenopathy. MENINGITIS; ENCEPHALITIS; and MYELITIS may also occur. [fpnotebook.com]

  Your child has a severe headache. Your child has a stiff neck. Your child is nauseated or is vomiting. Your child is confused or cannot think clearly. [myhealth.alberta.ca]

  In adults and older children, symptoms include: fever drowsiness bad headache and stiff neck nausea muscle tremors dizziness. In young children the symptoms include: fever floppiness irritability drowsiness fits. [ww2.health.wa.gov.au]

• Tremor

  A 57-year-old Caucasian woman presented with fever, dizziness, balance difficulties, vomiting, dancing eye, altered speech, tremor, generalized myoclonus and failure to rise or stand. [ncbi.nlm.nih.gov]

  Gait instability, coarse tremor, and bulbar palsy have been described. Less frequently reported are seizures and cerebral edema. [symptoma.com]

  Over a period of several days, his mental status improved completely to baseline and his fever and tremors subsided. [hindawi.com]

  […] majority of cases but that can present in rare occasions with mild flulike symptoms such as low-grade fever, arthralgia, myalgia, and/or rash, or with neurologic manifestations including meningitis, encephalitis with mental confusion or disorientation, tremors [orpha.net]

• Confusion

  This illness can cause confusion, a high fever, and a severe headache. Other symptoms include nausea, vomiting, and a stiff neck and back. West Nile virus is not spread by touching a person who has the virus. [myhealth.alberta.ca]

  Changes in the mental status range from acute confusion to coma. Gastrointestinal upset (nausea and vomiting) is common. Gait instability, coarse tremor, and bulbar palsy have been described. Less frequently reported are seizures and cerebral edema. [symptoma.com]

  More than one third of adult survivors of WNV infection continue to experience muscular weakness, cognitive impairment (for example, confusion, difficulty concentrating), or both after 12 months. [medical-dictionary.thefreedictionary.com]

  An 89-year-old man presented to a community hospital in October 2001 with fever and confusion. Except for recurrent hematuria, he had been in good health until the day before admission. [nejm.org]

  […] that is asymptomatic in the majority of cases but that can present in rare occasions with mild flulike symptoms such as low-grade fever, arthralgia, myalgia, and/or rash, or with neurologic manifestations including meningitis, encephalitis with mental confusion [orpha.net]

• Neck Stiffness

  More severe symptoms may include: headache high fever neck stiffness disorientation coma tremors convulsions muscle weakness paralysis In very rare cases, severe illness may cause death. [yavapai.us]

  Symptoms of severe illness include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. [cdc.gov]

  Symptoms of West Nile encephalitis include headache, fever, neck stiffness, disorientation, and muscle weakness. Death may result. [britannica.com]

• Seizure

  Occipital lobe seizures, often mimicking other primary seizure types due to extra-occipital spread, is uncommon in adults and especially so from an infectious origin. [ncbi.nlm.nih.gov]

  Institute safety and seizure precautions as indicated by the patient's neurologic status. Reorient the patient as necessary. Observe for signs and symptoms of increased intracranial pressure (ICP). [quizlet.com]

  The transient nature of his encephalopathy raised suspicion of a generalized seizure as the inciting event with resultant temporary postictal state. [hindawi.com]

  Less frequently reported are seizures and cerebral edema. Parkinsonism, extrapyramidal manifestations, myoclonus, and muscle weakness mimicking lower motor neuron lesions, also form part of the clinical picture. [symptoma.com]

  Monitor for seizures. B. Anticipated Length of Stay. Variable depending on severity of infection: from days to weeks. C. When is the Patient Ready for Discharge. [clinicaladvisor.com]

The main diagnostic test for WNV infection is the IgM antibody-capture enzyme-linked immunosorbent assay (MAC-ELISA) [7]. IgM antibodies may be detected in serum, however, when they are present in cerebrospinal fluid (CSF) this indicates central nervous system (CNS) invasion by the virus (as IgM does not cross the blood-brain barrier). Eventually, this confirms the diagnosis of West Nile encephalitis. The majority of patients will test positive at the time of presentation [8]. Moreover, nearly all patients are MAC-ELISA positive after a week of symptomatic illness.

Immunological assays may be supplemented by the use of nucleic acid amplification test (NAAT), thus improving the detection rate to over 90%. One advantage that NAAT has over immunology is that it can detect viral infection even in immunosuppressed patients who may produce a scarce amount of antibodies.

Raised white blood cell count may be a feature of WNE, although it is not always present. Increased leukocytes, either neutrophils or lymphocytes, and elevated protein level are some of the CSF findings [9]. T2-weighted magnetic resonance imaging (MRI) may sometimes reveal brainstem and periventricular lesions [10] [11].

• Hyponatremia

  Blood work to follow up on any remaining abnormalities noted while under acute care (e. g. sodium level in cases associated with hyponatremia). E. Placement Considerations. [clinicaladvisor.com]

  Laboratory evaluation was significant only for mild hyponatremia (132 mmol/L) and elevated creatinine kinase (236 mmol/L). Tests for liver function, complete blood count, and urinalysis were unremarkable. [hindawi.com]

  […] been described. 10–13 Back to Top Diagnosis Laboratory Findings Complete blood counts on admission usually show no major abnormalities, although there may be absolute or relative lymphopenia. 10,21 Up to one third of the patients develop significant hyponatremia [clevelandclinicmeded.com]

  Elevated creatinine kinase and hyponatremia, and elevated serum ferritin late in the course of illness, have also been reported. [ncbi.nlm.nih.gov]

Topical treatments may be prescribed for infections that affect the skin and nails while fluconazole pills are the treatment of choice for thrush. [navicenthealth.org]

After a treatment with interferon-α 3mu, follow up CSF findings recovered completely after 3 months later. The first case of West Nile encephalitis in Korea was imported from Guinea, and was cured successfully. [ncbi.nlm.nih.gov]

Patients and investigators will be blinded to treatment assignments. Patients will receive a single intravenous dose of study medication or one of two placebos. [clinicaltrials.gov]

Prognosis may be related to the degree of relative lymphopenia on presentation, the degree of elevation of serum ferritin levels and advanced age. [ncbi.nlm.nih.gov]

Prognosis and Patient Counseling. WNV encephalitis is associated with a poor prognosis in severely affected patients and in the elderly. A case fatality rate of approximately 14 percent in encephalitis cases has been reported. [clinicaladvisor.com]

What is the prognosis of West Nile virus infection? Since 80% of people who get infected never have any symptoms or signs, the overall prognosis (or likelihood of full recovery) is excellent. [medicinenet.com]

CONCLUSION: West Nile virus (WNV) etiology was confirmed by virus isolation and detection of virus specific antibody from clinical specimen. Phylogenetic analysis grouped the current strain in lineage I West Nile virus. [ncbi.nlm.nih.gov]

STUDY DESIGN: Investigation of outbreak was undertaken by collection of brief clinical history and epidemiological details along with the specimens for viral diagnosis. [ncbi.nlm.nih.gov]

( JAMA ). [ Reference ] The report of the extensive epidemiologic investigation of the 2012 WNV epidemic and the prior 10 years of WNV experience in Dallas County appeared in the July 2013 issue of JAMA. [ Reference ] [utsouthwestern.edu]

If you have any questions please contact the Bureau of Epidemiology at 832-393-5080. [houstontx.gov]

Pathophysiology, vector transmission, clinical manifestations and laboratory findings are discussed in this article. [ncbi.nlm.nih.gov]

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test West Nile virus (WNV) is a mosquito-borne flavivirus (single stranded RNA virus) that primarily infects birds, but occasionally [mayomedicallaboratories.com]

The pathophysiology underlying this phenomenon may be substantial yet reversible damage to some motor neurons that can eventually recover, and this recovery may result in strength improvement. [academic.oup.com]

Pathophysiology The WNV vector is the Culex mosquito, which typically feeds around dusk and dawn. Virus-laden saliva from the carrier mosquito infects the host. [emedicine.medscape.com]

Prevention effort should be focused on the elderly (≥60 years old) people who have a higher risk of severe sequelae. The state health authorities should create awareness among people in order to prevent the transmission of disease. J. Med. [ncbi.nlm.nih.gov]

Clark Dutterer, a preventive medicine specialist at the U.S. Army Center for Health Promotion and Preventive Medicine at Aberdeen Proving Ground, Maryland, sets a light trap to catch adult mosquitoes in the Maryland woods. [infoplease.com]

Centers for Disease Control and Prevention. "West Nile, a Pregnancy Danger?" Feb. 28, 2004.. United States. Centers for Disease Control and Prevention. "West Nile Virus." Aug. 8, 2011.. United States. Centers for Disease Control and Prevention. [medicinenet.com]

1. Mostashari F,Bunning ML, Kitsutani PT, et al. Epidemic West Nile encephalitis, New York, 1999: results of a household-based seroepidemiological survey. Lancet. 2001;358(9278):261–264.
2. Bode AV, Sejvar JJ, Pape WJ, Campbell GL, Marfin AA. West Nile virus disease: a descriptive study of 228 patients hospitalized in a 4-county region of Colorado in 2003. Clin Infect Dis. 2006;42(9):1234–1240.
3. Sayao AL, Suchowersky O, Al-Khathaami A, et al. Calgary experience with West Nile virus neurological syndrome during the late summer of 2003. Can J Neurol Sci. 2004;31(2):194–203.
4. Pepperell C, Rau N, Krajden S, et al. West Nile virus infection in 2002. CMAJ. 2003;168(11):1399–1405.
5. Hayes EB, Sejvar JJ, Zaki SR, Lanciotti RS, Bode AV, Campbell GL. Virology, pathology, and clinical manifestations of West Nile virus disease. Emerg Infect Dis. 2005;11(8):1174–1179.
6. Hayes EB, Komar N, Nasci RS, Montgomery SP, O’Leary DR, Campbell GL. Epidemiology and transmission dynamics of West Nile virus disease. Emerg Infect Dis. 2005;11(8):1167–1173.
7. Roehrig JT, Nash D, Maldin B, et al. Persistence of virus-reactive serum immunoglobulin M antibody in confirmed West Nile virus encephalitis cases. Emerg Infect Dis. 2003;9(3):376–379.
8. Tilley PA, Fox JD, Jayaraman GC, Preiksaitis JK. Nucleic acid testing for West Nile virus RNA in plasma enhances rapid diagnosis of acute infection in symptomatic patients. J Infect Dis. 2006;193(10):1361–1364.
9. Tyler KL, Pape J, Goody RJ, Corkill M, Kleinschmidt-DeMasters BK. CSF findings in 250 patients with serologically confirmed West Nile virus meningitis and encephalitis. Neurology. 2006;66(3):361–365.
10. Gyure KA. West Nile virus infections. J Neuropathol Exp Neurol. 2009;68(10):1053–1060.
11. Ali M, Safriel Y, Sohi J, et al. West Nile virus infection: MR imaging findings in the nervous system. AJNR Am J Neuroradiol. 2005;26(2):289–297.