2/26/03 SAS West Nile Virus Information for the Health Care Professional Mississippi State Department of Health 2/24/2003

2/26/03 SAS

West Nile VirusWest Nile VirusInformation for the Health Care ProfessionalInformation for the Health Care Professional

Mississippi State Department of Health 2/24/2003

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What Is West Nile Virus?What Is West Nile Virus?• Arbovirus (arthropod-borne virus) that can cause

infection/inflammation of spinal cord and or brain• Illness can occur in

– Birds – Humans– Horses

• Transmitted by mosquitoes, and rarely by blood transfusion, organ transplant, transplacental, or breast milk

• It has not been shown to be transmitted through contact with an infected bird, human, or horse but is theoretically possible

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History of West Nile Virus:History of West Nile Virus:OriginOrigin

The first case of The first case of West Nile virus West Nile virus was from a was from a woman in the woman in the West Nile West Nile Region of Region of Uganda, Africa Uganda, Africa in 1937in 1937

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Watch it Spread…..Watch it Spread…..

1999 to 20021999 to 2002

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It’s even crossed over into It’s even crossed over into Canada and Mexico…Canada and Mexico…

QuebecQuebecOntarioOntarioManit.Manit.Saskat.Saskat.

OntarioOntario

NovaNova

ScotiaScotia

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Human WNME (1 case), 2001

Equine WNME (<5 cases), 2002

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West Nile Virus:West Nile Virus:Approximate Worldwide Geographic RangeApproximate Worldwide Geographic Range

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TransmissionTransmissionHow is it Spread?How is it Spread?

Primarily maintained in a bird-Primarily maintained in a bird-mosquito cycle…. mosquito cycle….

……but can spill over to other animals but can spill over to other animals including humans and horses including humans and horses

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Arbovirus SurveillanceArbovirus Surveillance Mississippi ActivitiesMississippi Activities

To identify WNV activity, the MSDH To identify WNV activity, the MSDH routinely performs the following routinely performs the following activities:activities:

• Dead Bird Report Surveillance Dead Bird Report Surveillance • Dead Bird TestingDead Bird Testing• Horse TestingHorse Testing• Mosquito Collection and Testing Mosquito Collection and Testing • Human TestingHuman Testing

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““There’s a dead bird in my yard!!”There’s a dead bird in my yard!!”

The Public is encouraged to report all dead The Public is encouraged to report all dead birds to their local health department or the birds to their local health department or the

WNV hot line: WNV hot line:

1-877-WST-NILE1-877-WST-NILE

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Signs & Symptoms:Signs & Symptoms:Incubation PeriodIncubation Period

Signs and Symptoms Signs and Symptoms MAYMAY develop 3-15 develop 3-15 days after being days after being

bitten by an bitten by an infected infected mosquitomosquito

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Signs & Symptoms:Signs & Symptoms:PresentationsPresentations

• Most are asymptomatic (80%)Most are asymptomatic (80%)

• Ill patients may present with a Ill patients may present with a spectrum of mild (20%) to severe spectrum of mild (20%) to severe (<1%) illness(<1%) illness

• Neurologic illness is often present Neurologic illness is often present with severe cases, or may present as with severe cases, or may present as it’s own entityit’s own entity

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Signs & Symptoms:Signs & Symptoms:PresentationsPresentations

• Mild IllnessMild Illness (WN Fever) (WN Fever)– usually does not progress to severe usually does not progress to severe

illnessillness

• Severe IllnessSevere Illness (meningoencephalitis) (meningoencephalitis)– May present with neurologic componentMay present with neurologic component

• Muscle Weakness or ParalysisMuscle Weakness or Paralysis– May present only with muscle weakness May present only with muscle weakness

or paralysis or stroke-like symptomsor paralysis or stroke-like symptoms

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Signs & Symptoms:Signs & Symptoms:Mild IllnessMild Illness

• Self-limitingSelf-limiting• Mild cases may include:Mild cases may include:

– FeverFever– HeadacheHeadache– Body achesBody aches– RashRash– Swollen lymph nodesSwollen lymph nodes– Gastrointestinal (nausea, vomiting)Gastrointestinal (nausea, vomiting)

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Signs & Symptoms:Signs & Symptoms:Severe IllnessSevere Illness

• Encephalitis Encephalitis – Inflammation of – Inflammation of the brain the brain

• Meningitis Meningitis - Inflammation of the - Inflammation of the lining of the brain or spinal lining of the brain or spinal cordcord

• Muscle Weakness / Paralysis or Muscle Weakness / Paralysis or other neurologic problemother neurologic problem - - Acute flaccid paralysis, Acute flaccid paralysis, tremors, myoclonustremors, myoclonus

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Sudden onset of:Sudden onset of:• High feverHigh fever• HeadacheHeadache• ConfusionConfusion• DisorientationDisorientation• TremorsTremors• Occasional seizuresOccasional seizures

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Other symptoms Other symptoms • Muscle weaknessMuscle weakness• ParalysisParalysis• Altered reflexesAltered reflexes• StuporStupor• TremorsTremorsMay result inMay result in• ComaComa• DeathDeathThe Elderly are at greater The Elderly are at greater risk for more severe illnessrisk for more severe illness

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Laboratory FindingsLaboratory Findings

• CBCCBC– WBC normal or elevated WBC normal or elevated – Lymphocytopenia may occurLymphocytopenia may occur– Anemia may occurAnemia may occur

• ChemistryChemistry– Hyponatremia sometimes present, particularly among Hyponatremia sometimes present, particularly among

patients with encephalitispatients with encephalitis

• CSFCSF– PleocytosisPleocytosis– Protein elevatedProtein elevated– Glucose normalGlucose normal

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Diagnostic FindingsDiagnostic Findings

• CT’sCT’s– No evidence of acute disease No evidence of acute disease

• MRI’s MRI’s – Enhancement of leptomeninges and or Enhancement of leptomeninges and or

periventricular areas seen in 1/3 of periventricular areas seen in 1/3 of patients patients

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Laboratory TestingLaboratory Testing• IgM MAC-ELISA IgM MAC-ELISA (antibody capture enzyme-linked (antibody capture enzyme-linked

immunosorbent assay)immunosorbent assay)

– Most efficient diagnostic method Most efficient diagnostic method – Serum or CSF Serum or CSF – IgM antibody does not cross blood-brain barrier thus IgM IgM antibody does not cross blood-brain barrier thus IgM

in CSF suggests CNS infectionin CSF suggests CNS infection• PRNT PRNT (plaque reduction neutralization)(plaque reduction neutralization)

– Confirmation test for positive serum Confirmation test for positive serum • PCR PCR (polymerase chain reaction)(polymerase chain reaction)

– Inefficient due to short duration of viremiaInefficient due to short duration of viremia– Can help diagnose in immunocompromised Can help diagnose in immunocompromised

• CSF or tissue onlyCSF or tissue only

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Laboratory TestingLaboratory Testing• May be difficult to interpretMay be difficult to interpret

– IgM levels may persist for more than one yearIgM levels may persist for more than one year• New infection vs old infection?New infection vs old infection?• Need clinical informationNeed clinical information• May need convalescent sample or IgA titer for serum May need convalescent sample or IgA titer for serum

samplessamples

– Tests of a single acute-phase (serum or CSF) Tests of a single acute-phase (serum or CSF) specimen may be diagnostically inconclusivespecimen may be diagnostically inconclusive

– Cross reactivity between flaviviruses Cross reactivity between flaviviruses • With WNV + test, may see SLE + and vice versaWith WNV + test, may see SLE + and vice versa

• Samples collected too acute (< 7 days) in the Samples collected too acute (< 7 days) in the course of illness may yield false negative resultscourse of illness may yield false negative results

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Laboratory Testing Laboratory Testing CollectionCollection

• Include MSDH submission formInclude MSDH submission form

• Serum specimen of choice because Serum specimen of choice because fewer antibodies in CSF fewer antibodies in CSF

• Ship all samples with cold packsShip all samples with cold packs

• Do NOT use polystyrene tubesDo NOT use polystyrene tubes

• Do NOT freeze specimensDo NOT freeze specimens

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Laboratory Testing Laboratory Testing CollectionCollection

• SeraSera– Collect in tube with gel separator Collect in tube with gel separator – Spin sample for shipping as free Spin sample for shipping as free

hemoglobin may result in false positive hemoglobin may result in false positive resultsresults

– Once separated, serum can be held at Once separated, serum can be held at 2 – 8 C2 – 8 C

• CSFCSF– Can be held at 2 – 8 CCan be held at 2 – 8 C

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Laboratory Testing Laboratory Testing IgM ELISA for WNVIgM ELISA for WNV

Results from the MSDH-PHL for acute WNV infections Results from the MSDH-PHL for acute WNV infections are interpreted as follows:are interpreted as follows:

SerumSerum• Reactive Reactive CASE-PROBABLECASE-PROBABLE

– If also positive by PRNT If also positive by PRNT CASE-CONFIRMEDCASE-CONFIRMED• Gray Zone Gray Zone SUSPECTSUSPECT

– Not a CaseNot a Case– Requires convalescent sample and or PRNTRequires convalescent sample and or PRNT

• Non-Reactive Non-Reactive NEGATIVENEGATIVE– May consider retesting depending on collection dateMay consider retesting depending on collection date

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CSFCSF• Reactive Reactive CASE-CONFIRMEDCASE-CONFIRMED

– Does not require PRNT Does not require PRNT

• Gray Zone Gray Zone SUSPECTSUSPECT– Requires convalescent sample or PRNTRequires convalescent sample or PRNT– Or consider paired seraOr consider paired sera

• Non-Reactive Non-Reactive NEGATIVENEGATIVE– Consider re-testing depending on collection dateConsider re-testing depending on collection date– Or consider paired seraOr consider paired sera

*For immune-compromised consider PCR *For immune-compromised consider PCR testing of CSFtesting of CSF

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CSF or SerumCSF or Serum• InconclusiveInconclusive

INCONCLUSIVEINCONCLUSIVE– Most inconclusive results are due to Most inconclusive results are due to

non-specific binding of patient serum non-specific binding of patient serum or CSF to test componentsor CSF to test components

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Laboratory TestingLaboratory Testing

• Testing free of charge by the MSDH-Testing free of charge by the MSDH-Public Health LabPublic Health Lab– (601)576-7582 or(601)576-7582 or– 1-877-WST-NILE (1-877-978-6453)1-877-WST-NILE (1-877-978-6453)

• Vaccination or infection with related Vaccination or infection with related flaviviruses (e.g., yellow fever, flaviviruses (e.g., yellow fever, Japanese encephalitis, dengue) may Japanese encephalitis, dengue) may result in positive testresult in positive test

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No specific therapy No specific therapy Only supportive care for severe Only supportive care for severe

infectionsinfections• HospitalizationHospitalization• IV fluids,nutritionIV fluids,nutrition• Ventilator supportVentilator support• Prevention of secondary infectionsPrevention of secondary infections• Good nursing careGood nursing care• RibavirinRibavirin in high doses and in high doses and interferon interferon

alpha-2balpha-2b show activity in vitro show activity in vitro• No clinical data yet - nor for other No clinical data yet - nor for other

meds, including steroids, antiseizure meds, including steroids, antiseizure drugs, or osmotic agentsdrugs, or osmotic agents

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Outcome of WNV Patients Outcome of WNV Patients Mississippi 2002Mississippi 2002

Discharged to:Discharged to: PercentPercentDiedDied 6.2% 6.2%Home Home 59.6% 59.6% Nursing home Nursing home 3.4%3.4%NeverNever 28.1% 28.1% hospitalizedhospitalizedRehab Rehab 1.7% 1.7% Unknown Unknown 6.4%6.4%

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WNV PatientsWNV Patients Mississippi 2002Mississippi 2002

• Most patients presented with Most patients presented with meningoencephalitis (ME)meningoencephalitis (ME)

• Asymptomatic persons and most patients Asymptomatic persons and most patients with mild illness do not seek medical carewith mild illness do not seek medical care

PresentationPresentationPercentPercent

WN Fever WN Fever 16% 16%

ME ME 84% 84%

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WNV PatientsWNV Patients Mississippi 2002Mississippi 2002

PercentPercent

Fever Fever 91.5%91.5%

Headache Headache 72.3%72.3%

Muscle Weakness Muscle Weakness 56.9%56.9%

NauseaNausea 50.8%50.8%

Vomiting Vomiting 35.8%35.8%

Muscle painMuscle pain 34.6%34.6%

Altered mental Altered mental 34.6%34.6%

statusstatus

PercentPercent

Stiff neckStiff neck 29.8%29.8%

Rash Rash 25.0%25.0%

Joint pain Joint pain 24.5%24.5%

Lethargy Lethargy 24.6%24.6%

Lymphadenopathy 3.7%Lymphadenopathy 3.7%

Seizures Seizures 2.1% 2.1%

Signs and symptoms among MS patients:Signs and symptoms among MS patients:

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WNV PatientsWNV Patients Physical and Cognitive ImpairmentsPhysical and Cognitive Impairments

Frequency of physical and cognitive Frequency of physical and cognitive complaints before and after WNV illnesscomplaints before and after WNV illness

(n=84) (n=84)

COMPLAINTCOMPLAINT PRE PRE POST POST

Muscle WeaknessMuscle Weakness 4.2%4.2% 56%56%

Difficulty walkingDifficulty walking 14.4%14.4% 50.6%50.6%

FatigueFatigue 28%28% 65.5%65.5%

General malaiseGeneral malaise 21.5%21.5% 48.8%48.8%

ConfusionConfusion 9.6%9.6% 27.4%27.4%

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West Nile VirusWest Nile VirusPreventionPrevention

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PreventionPrevention

Mosquitoes can develop in any

standing water that lasts more than 4

days

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PreventionPrevention• Properly dispose of water-Properly dispose of water- holding containersholding containers• Drill holes in bottom of recyclingDrill holes in bottom of recycling containers kept outdoorscontainers kept outdoors• Cover rain water collectionCover rain water collection containers with window containers with window screening to prevent femalescreening to prevent female mosquitoes from laying eggs in mosquitoes from laying eggs in the waterthe water

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• Make sure roof gutters Make sure roof gutters

drain properly, and clean drain properly, and clean

clogged gutters in the clogged gutters in the

spring and fallspring and fall• Change water in bird bathsChange water in bird baths

twice weeklytwice weekly• Turn over plastic wadingTurn over plastic wading

pools and wheelbarrows when not in usepools and wheelbarrows when not in use

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• Clean and chlorinate Clean and chlorinate swimming pools, outdoor saunas, hot tubsswimming pools, outdoor saunas, hot tubs

• Drain water from pool coversDrain water from pool covers• Clean vegetation and debris from the edge Clean vegetation and debris from the edge

of ornamental pondsof ornamental ponds• Use landscaping to eliminate water from Use landscaping to eliminate water from

your propertyyour property• Fill in potholes in drivewaysFill in potholes in driveways

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• Make sure all windows Make sure all windows and doors have and doors have screensscreens

• Keep all screens Keep all screens repaired (fix holes and repaired (fix holes and rips)rips)

• Repair glass in broken Repair glass in broken windowswindows

• Keep doors closedKeep doors closed

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Prevention:Prevention:Personal protectionPersonal protection

• Minimize outdoor Minimize outdoor activities between activities between dusk and dawn, many dusk and dawn, many mosquitoes are active mosquitoes are active at these timesat these times

• However, other However, other mosquito species can mosquito species can be active during the be active during the late afternoonlate afternoon

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Wear shoes and Wear shoes and socks, long pants socks, long pants and a long-sleeved and a long-sleeved shirt when outdoors shirt when outdoors for a long period of for a long period of time, or when time, or when mosquitoes are mosquitoes are more activemore active

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• Consider use of mosquito repellents. Consider use of mosquito repellents. Carefully read and follow all label Carefully read and follow all label instructionsinstructions

• Repellents containing 10 to 35% DEET for Repellents containing 10 to 35% DEET for adultsadults

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Children and Insect RepellentsChildren and Insect Repellents

• Keep repellents out of reach of childrenKeep repellents out of reach of children• Don’t allow children to apply repellents to Don’t allow children to apply repellents to

themselvesthemselves• Rub repellent on skin of child; do not sprayRub repellent on skin of child; do not spray• Use small amounts of repellent on children Use small amounts of repellent on children

and follow label instructions carefullyand follow label instructions carefully• Do not apply to the hands of young childrenDo not apply to the hands of young children• American Academy of Pediatrics American Academy of Pediatrics

recommends 10% DEET for childrenrecommends 10% DEET for children

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Fight the BiteFight the Bite MSDH ObjectivesMSDH Objectives

• Promote public cooperation to reduce Promote public cooperation to reduce mosquito breeding sitesmosquito breeding sites

• Help individuals reduce their risk of being Help individuals reduce their risk of being bitten by mosquitoesbitten by mosquitoes

• Educate providers about WNVEducate providers about WNV• Enlist media to present accurate Enlist media to present accurate

representations of WNVrepresentations of WNV• Focus on high-risk populationsFocus on high-risk populations

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Call the MSDH if you have any questions at:Call the MSDH if you have any questions at:

• WNV Hot lineWNV Hot line

1 – 877 - WST – NILE 1 – 877 - WST – NILE

• Division of EpidemiologyDivision of Epidemiology

601 – 576 – 7725601 – 576 – 7725

• Public Health LaboratoryPublic Health Laboratory

601-576-7582601-576-7582

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Or visit the web site at:Or visit the web site at:

www.msdh.state.ms.uswww.msdh.state.ms.usor the CDC web site at:or the CDC web site at:

www.cdc.govwww.cdc.gov

Documents

2/26/03 SAS West Nile Virus Information for the Health Care Professional Mississippi State Department of Health 2/24/2003