West Nile VirusMichigan - 2002

Mary Grace Stobierski, DVM,MPH,DACVPMMary Grace Stobierski, DVM,MPH,DACVPM

Michigan Dept. Community HealthMichigan Dept. Community Health

West Nile Virus 2002, A Season of Surprises Largest arbovirus meningoencephalitis Largest arbovirus meningoencephalitis

outbreak epidemic ever documented in outbreak epidemic ever documented in western hemispherewestern hemisphere

Largest WNME epidemic ever documentedLargest WNME epidemic ever documented Geographic spread to the Pacific CoastGeographic spread to the Pacific Coast Clinical syndromes (Acute Flaccid Clinical syndromes (Acute Flaccid

Paralysis, was not Guillian-Barre syndrome)Paralysis, was not Guillian-Barre syndrome) New modes of transmissionNew modes of transmission

Novel Modes of West Nile Virus Transmission, 2002 Transplanted organsTransplanted organs Transfused bloodTransfused blood Breast milkBreast milk Percutaneous, occupational exposurePercutaneous, occupational exposure Prenatal transmissionPrenatal transmission

                                                                           

       

Any WNV Activity Reported - 2002

                                                                           

       

Human Cases

WNV Hotline Calls* 2002 (operated by MDCH staff)

0

5000

10000

15000

20000

25000

July August September

# calls

1/888/668-0869

* >35,000 calls in Aug & Sept

Michigan Department of Community Health Announces Probable Human Cases of West Nile Virus August 16, 2002 Michigan Department of Community Health Chief Medical Executive, David R. Johnson M.D., todayannounced two probable human cases of West Nile virus.  Laboratory samples have been sent to the Centers for Disease Control and Prevention for confirmatory testing.  The first case involves an 82 year-old male from Southeast Michigan who was hospitalized and hasbeen released in good condition.  The second involves a 63 year-old male from Southeast Michiganwho is currently hospitalized and appears to be improving. 

“We are encouraged that both of these gentlemen appear to be recovering and we will continue to workwith health care providers throughout Michigan to quickly identify any other potential human cases,” said Dr. Johnson.  “The most important thing a person can do to protect themselves from West Nile virus is to follow the common-sense precautions to minimize exposure to mosquitoes.” 

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100

150

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250

300

350

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5

10

15

20

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30

35

Phone Calls Human Cases

Phone Reports of Dead Birds versus Human Cases in Michigan for 2002

Data from 614 out of 644 human cases

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10

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25

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35

Onset Date

Nu

mb

er o

f C

ases

Confirmed Probable

Onset Date of Symptoms Among Human West Nile Virus Cases in Michigan for 2002

Data from 614 of the 644Total Cases

WNVHuman cases Michigan 2002*

644 cases51 deaths *(Total Cases/Deaths)

(Includes probable andconfirmed cases, all clinicalsyndromes)

Michigan WNV Case Statistics:

All CasesAll Cases

Age range: 9mo-95yrsAge range: 9mo-95yrs

Ave Age: 57.6Ave Age: 57.6

% Female: 45% Female: 45

% Male: 55% Male: 55

DeathsDeaths

Age range: 24-95 yrsAge range: 24-95 yrs

Ave Age: 74.5Ave Age: 74.5

% Female: 41% Female: 41

% Male: 59% Male: 59

West Nile Virus Case Summary 

Total Laboratory Positive Cases: 644 West Nile Meningo-encephalitis cases: 559 (87%) Age range: .75-95 yrs Average age: 57.8 yrs West Nile Fever cases: 57 (9%) Age range: 3-80 yrs Average Age: 47.7 yrs Unknown cases: 28 (4%) Deaths: 51 (9%) Age range: 24-95 yrs Average age: 74.5 yrs

2002 Cases by Agegroup - 2002

0

20

40

60

80

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120

140

< 10yrs

11-20yrs

21-30yrs

31-40yrs

41-50

yrs

51-60yrs

61-70yrs

71-80yrs

81-90yrs

> 90yrs

# CASES

N=639 cases

Additional Arboviruses in 2002

St. Louis Encephalitis: 3 casesSt. Louis Encephalitis: 3 cases Eastern Equine Encephalitis: 6 casesEastern Equine Encephalitis: 6 cases LaCrosse Encephalitis: 11 casesLaCrosse Encephalitis: 11 cases Powassan virus: 1 case (Emmet Co.) Powassan virus: 1 case (Emmet Co.)

(tick borne encephalitis)(tick borne encephalitis)

First time ever documented case inFirst time ever documented case in

Michigan! Michigan!

Additional Arbovirus CasesMichigan, 2002

CountyCounty SLESLE EEEEEE LACLAC POWPOW

ClareClare 11

EatonEaton 11

EmmetEmmet 11

GeneseeGenesee 33

HuronHuron 11

KentKent 11

MacombMacomb 22 11

ManisteeManistee 11

OaklandOakland 11 22

OttawaOttawa 11

PresquePresque

IsleIsle

11

WayneWayne 22 22

Emphasis on Comprehensive Website

www.michigan.gov/westnilevirus

Decrease use of Hotline

The Transfusion Saga Begins in Michigan

August 2002

West Nile Virus Infection in an Organ Donor West Nile Virus Infection in an Organ Donor and Four Transplant Recipientsand Four Transplant Recipients

(GA & FL) August 2002(GA & FL) August 2002

Organ Donor

WNV PCR –IgM –

Organ Donor

WNV PCR +

Culture +IgM –

Kidney recipientWNME (fatal)

Kidney recipientWNME

Liver recipientWNF

Heart recipientWNME

Blood Blood components components

from 63 from 63 donorsdonors

Transfusion-associated West Nile virus infectionTransfusion-associated West Nile virus infection

BackgroundBackground

• Potential transmissionPotential transmission- Transient viremia- Transient viremia- Most infections asymptomatic- Most infections asymptomatic

• ““Small but not zero” riskSmall but not zero” risk- No chronic carriers- No chronic carriers- No cases reported in prior years or - No cases reported in prior years or

fromfrom endemic countries endemic countries

• Estimated risk: Estimated risk: 1.8-2.7/10,000 donations in 1.8-2.7/10,000 donations in 1999 Queens (NYC) epidemic1999 Queens (NYC) epidemic

Transfusion investigations in MI

Case #Case # AgeAge # Donors# Donors Underlying Underlying ConditionCondition

OutcomeOutcome

11 4747 3939 Liver Liver transplanttransplant

AliveAlive

22 4040 22 ObstetricObstetric AliveAlive

33 4444 44 Organ donorOrgan donor FatalFatal

44 1212 8383 LeukemiaLeukemia AliveAlive

55 7272 1010 CABGCABG FatalFatal

66 4343 Stem Cell Stem Cell TransplantTransplant

Not WNVNot WNV

77 5151 7979 LeukemiaLeukemia FatalFatal

88 7878 1010 MIMI FatalFatal

Transfusion investigations in MI, cont’dCase #Case # AgeAge # Donors# Donors Underlying Underlying

ConditionConditionOutcomeOutcome

99 7676 88 CancerCancer FatalFatal

1010 8080 88 DementiaDementia Not WNVNot WNV

1111 2626 1717 LeukemiaLeukemia AliveAlive

1212 6969 -- Blood DonorBlood Donor AliveAlive

1313 7575 44 CABGCABG AliveAlive

1414 77 1313 CancerCancer AliveAlive

1515 7373 2121 Co-recipientCo-recipient AliveAlive

CDC Protocol: Investigation of transfusion-CDC Protocol: Investigation of transfusion-associated West Nile virus infectionassociated West Nile virus infection

• Comprehensive chart review of caseComprehensive chart review of case

• Determine number & type of components transfused Determine number & type of components transfused to recipient in 4 weeks before WNV illness onsetto recipient in 4 weeks before WNV illness onset

Retrieve “initial donation samples” (retention Retrieve “initial donation samples” (retention segments, untransfused product, NAAT tubes)segments, untransfused product, NAAT tubes)

Test for WNV RNA (TaqMan rtPCR) and IgM Test for WNV RNA (TaqMan rtPCR) and IgM antibody (ELISA)antibody (ELISA)

• Donor F/U serum questionnaire & serum sample for Donor F/U serum questionnaire & serum sample for WNV IgM antibody testWNV IgM antibody test

• F/U questionnaire & WNV IgM antibody testing of F/U questionnaire & WNV IgM antibody testing of “other recipients” who received “suspect” blood “other recipients” who received “suspect” blood product (if indicated)product (if indicated)

Case definition: Confirmed transfusion-Case definition: Confirmed transfusion-associated West Nile virus infectionassociated West Nile virus infection

• Probable/confirmed WNV illness* in blood product Probable/confirmed WNV illness* in blood product recipientrecipient

• Transfusion within 4 weeks of illness onsetTransfusion within 4 weeks of illness onset

• Evidence of viremia in donor:Evidence of viremia in donor:TaqMan-positiveTaqMan-positive index donation sample(s) index donation sample(s)

ANDAND virus isolation virus isolationOROR

TaqMan-positiveTaqMan-positive index donation sample(s) index donation sample(s)ANDAND seroconversion in donor seroconversion in donor

* CDC. Epidemic/Epizootic West Nile Virus in the United States: * CDC. Epidemic/Epizootic West Nile Virus in the United States: Revised Guidelines for Surveillance, Prevention, and Control, April Revised Guidelines for Surveillance, Prevention, and Control, April 2001.2001.

First 3 MI cases are relatedMI 001MI 001 MI 002MI 002 MI 003MI 003

47yr,Wayne47yr,Wayne 40yr, Macomb40yr, Macomb 44yr, 44yr, Wayne/OaklandWayne/Oakland

Liver transplant; Liver transplant; recoveredrecovered

Obstetric; Obstetric; healthy infanthealthy infant

Liver donor; Liver donor; deceaseddeceased

CSF WNV +CSF WNV + CSF WNV +CSF WNV + All tissues All tissues WNV -WNV -

One blood One blood component component w/MI 002w/MI 002

One blood One blood component component w/MI 001w/MI 001

Donor to MI Donor to MI 001; but,not the 001; but,not the source of WNVsource of WNV

MI 0001 & MI 0002 Found to have one blood component in commonFound to have one blood component in common

Blood component in common found to be Taqman Blood component in common found to be Taqman PCR positive @ CDCPCR positive @ CDC

Donor of blood traced; Wayne county resident; Donor of blood traced; Wayne county resident; reported symptoms 3 days post-donationreported symptoms 3 days post-donation Fever, rash, myalgia, minor weakness. Fever, rash, myalgia, minor weakness.

Recovered 6-7 days later. Blood sample Recovered 6-7 days later. Blood sample 10/7/02 IgM + at CDC10/7/02 IgM + at CDC..

MI 0002 cont’d

Breast milkBreast milk Sample collected 9/19: Taqman +, IgM +, Sample collected 9/19: Taqman +, IgM +,

IgG +; Viral culture - at CDCIgG +; Viral culture - at CDC Sample collected 9/27: Taqman -, IgM +Sample collected 9/27: Taqman -, IgM +

Infant test resultsInfant test results Serum collected 9/27: IgM + Serum collected 9/27: IgM + (MDCH & CDC)(MDCH & CDC)

PKU card: Taqman - (MDCH)PKU card: Taqman - (MDCH)

MI 0002 cont’d

Mother reported infant had little outdoor or other Mother reported infant had little outdoor or other exposure to mosquitoesexposure to mosquitoes

Presence of measurable WNV-specific IgM Presence of measurable WNV-specific IgM suggests independent IgM production by infant as suggests independent IgM production by infant as result of WNV infection via breast milkresult of WNV infection via breast milk

No change in breastfeeding recommendationsNo change in breastfeeding recommendations

MMWR10/4/2002

TransmissionVia Breast Feeding

MI0004 Case Detail

12 year old, AML12 year old, AML

Had been in isolation at hospital for 65 continuous Had been in isolation at hospital for 65 continuous daysdays

Received 83 blood componentsReceived 83 blood components

No mosquito exposure, thus only means of No mosquito exposure, thus only means of transmission was via blood transfusiontransmission was via blood transfusion

Transfusion Investigations:Michigan Summary

15 Investigations15 Investigations

Patients: 7 yr – 80 yrPatients: 7 yr – 80 yr Includes 2 donors (1 organ and 1 blood)Includes 2 donors (1 organ and 1 blood)

# Blood Components: 2 – 83# Blood Components: 2 – 83

5 Fatal5 Fatal

2 Subsequently ruled out as WNV2 Subsequently ruled out as WNV

West Nile virus infections in blood transfusion West Nile virus infections in blood transfusion recipients, US Summaryrecipients, US Summary

61 possible cases reported to CDC since Aug 28, 200261 possible cases reported to CDC since Aug 28, 2002

19 19 notnot transfusion-associated WNV transfusion-associated WNV

21 had inconclusive investigations21 had inconclusive investigations

23 confirmed cases of transfusion-associated transmission23 confirmed cases of transfusion-associated transmission

Aged 7-90 yearsAged 7-90 years

12 Female; 11 Male12 Female; 11 Male

10 were immunocompromised10 were immunocompromised

Prevention of Transfusion-Related Infection Current: donor screeningCurrent: donor screening FDA encouraging development of nucleic acid-FDA encouraging development of nucleic acid-

based screening testsbased screening tests Will pooled nucleic acid testing have Will pooled nucleic acid testing have

high enough sensitivity?high enough sensitivity?Can these tests, if developed, be Can these tests, if developed, be

implemented in time for the 2003 season?implemented in time for the 2003 season? Retrieval & quarantine of blood products Retrieval & quarantine of blood products

collected during 2002 epidemic periodcollected during 2002 epidemic period

Intrauterine WNV InfectionNew York, August 2002 20 yr old in 2720 yr old in 27thth week of pregnancy week of pregnancy

Fever, H/A, blurred vision, vomiting, Fever, H/A, blurred vision, vomiting, abdominal & back pain, severe weakness.abdominal & back pain, severe weakness.

5 weeks later, delivered a live infant; has a 5 weeks later, delivered a live infant; has a number of congenital abnormalities.number of congenital abnormalities.

Mother: serum & CSF IgM +Mother: serum & CSF IgM + Infant: serum & CSF IgM +Infant: serum & CSF IgM +

MMWR Vol.51/No.50MMWR Vol.51/No.50

Laboratory-Acquired WNV

2 laboratory workers2 laboratory workers Percutaneous inoculationPercutaneous inoculation Illnesses in both: mild & self-limitingIllnesses in both: mild & self-limiting

Serum IgM (+) in both casesSerum IgM (+) in both cases

MMWR Vol 51/ No 50MMWR Vol 51/ No 50

West Nile virus, 2002:Emerging issues

Emergence in western U.S.Emergence in western U.S. New modes of transmissionNew modes of transmission

Breast milkBreast milk TransplacentalTransplacental Transfusion / transplantation Transfusion / transplantation Laboratory/occupationalLaboratory/occupational

Emerging clinical syndromesEmerging clinical syndromes WN feverWN fever WNME / acute flaccid paralysis WNME / acute flaccid paralysis WNME / rhabdomyolysisWNME / rhabdomyolysis

Long-term outcome studiesLong-term outcome studies

2002 SEASON CHALLENGES

Coordination between multiple agenciesCoordination between multiple agencies

Deluge of human case appearancesDeluge of human case appearances

Rapid communication of results to multiple partiesRapid communication of results to multiple parties

New modes of transmission discoveredNew modes of transmission discovered