West Nile VirusMiyuki Horie, MPH student

Walden UniversityPUBH 6165-3

Dr. Howard RubinWinter Qrt., 2012/13

Introduction

First West Nile virus cases in the world … Uganda, 1937

West Nile virus in the US … New York, 1999 Continue to re-emerge every year during the

summer Worst outbreaks in the US record … 2012

o Involved 48 stateso Killed 89 peopleo 1 death in Washington, DC

Objectives Know about West Nile virus (WNV) infection

o Route of Transmissiono Vectorso Clinical Symptomso People at Risko Treatment

Preventiono Around Youo Around Homestead

Where to contacto If contracted WNVo For additional Information

West Nile VirusFacts

Arthropod-borne virus = Arbovirus

Transmitted by mosquitos Can infect people, birds,

horses, and other mammals

Causes mild-flu like symptoms or sever symptoms in some

Seasonal epidemic between Summer –Fall(CDC, 2012c; DOH, 2012b; Winn et al., 2006)

WNVRoute of Transmission

Primary Transmission Cycle = Birds Mosquitos Incidental Transmission = Mosquitos Human, Horses

o Birds = Reservoiro Mosquitos = Vector o Human, Horses = Incidental host/Dead-end

(CDC, 2012a; DOH, n.d.; Huhn et al., 2003; Winn et al., 2006)

WNVBirds / Reservoir

Primary host/reservoir of West Nile virus

200+ species affected Infected birds become ill,

die, or survive with permanent immunity

Develops infectious viremia for 1-4 days

Migrant birds “ferry” WNV(CDC, 2012a; DHMH, 2013; Rappole, Derrickson, &

Hubálek, 2000; Winn et al., 2006)

WNVMosquitos / Vector

Life cycleEggs (in swamp/standing water) Larvae (in water) Pupae Adult

Maleso Live up to 7-10 dayso Feed on plant juice

Femaleso Live 30+ dayso Feed on animal bloodo Become infected with WNV when

feed on infected birdso Transmit WNV when feed on other

animal(CDC, 2012a; DOH, n.d.; EPA, 2012b; EPA, 2012c)

male female

WNVMosquitoes /Vector

Culex mosquito Asian Tiger mosquito

(cdc, 2005; DOH, n.d.)

• “Common house mosquito” in North America

• Yellow body + brown stripes on abdomen

• Feed on birds, other mammals• Active at dusk and down• Attracted by swampy/stagnant

water

• Originally from Asia• Large size• Black & white stripes on legs

and abdomen• Feed on mammals• Active all day• Attracted by CO2, humidity

WNVClinical Significance

No symptoms – 80% Mild symptoms – 20%

o Full-like symptomso Fevero Headacheo Body acheo Nauseao Skin rashes (torso)

Sever symptoms – Approx. 1 in 150 caseso “Neuroinvase WNV”: Encephalitis, Meningitis

• Disorientation, Comma, Convulsion, Tremors, Numbness, Paralysiso High fevero Headache + Neck stiffness o Death (3-15%)

(CDC, 2012c; Huhn et al., 2003; Salinas & Steiner, 2012)

WNVWho’s at Risk?

People who are risk are:o 0ver 50 years oldo Immunocompromisedo Working/spending many

hours outside Pregnant or nursing

women do NOT have increased risk for WNVo Only 1 case of mother-

fetus transmissiono No report/data on WNV

infection through Breastfeeding

(CDC, 2012b; CDC, 2012c; Huhn et al., 2003)

She’s Okay!

WNVTreatment

No specific treatment for WNV Self-limiting – Mild symptoms last only a few days No/Rare chronic case – person infected with WNV most

likely to acquire immunity Sever cases (Neuroinvasive WNV) should seek

medical attentiono Hospitalizationo Supportive care: IV fluids, Respiratory supporto Secondary prevention to reduce morbidityo Notification to Department of Health (DOH)(CDC, 2012b; DOH, 2012b)

WNVPrevention

No WNV Vaccine Primary prevention =

Avoid mosquito bite Use mosquito repellant

(e.g. DEET) when outside

Wear long-sleeve clothes Apply permethrin on to

the clothes Stay inside during the

mosquito-feeding hours (at dusk & dawn)

(CDC, 2012b; DOH, 2012a; EPA, 2012b)

ANTI

M

OSQU

ITO

(F51

06)

WNVMosquito Repellant

2 types of mosquito repellant recommended are… DEET (N, N-dimethyl-m-toluamide)

o Most effective & Widely availableo Directly apply onto the skino Select appropriate % for your need

• <30% DEET for children• 23.8% DEET… 5-hr protection• 6.65% DEET… 2-hr protection• 4% DEET… ~90-min protection

Permethrino Apply onto clothes for additional

protectiono No health concerns at low level(CDC, 2005; DOH, 2012a; DOH, 2012b; EPA, 2012a; FDACS, 2012)

WNVControl

“West Nile virus program”o Reduce mosquito-breeding sites in all 8 Wards in DC

• Dispose of old tires, cans and bottles and other containers• Clean roof gutters• Clear garbage area – Close the lid• Place tarp over grills, firewood piles, tires, boats• Turn over wading pools • Clean & Chlorinate swimming pools

Notify DOH for suspected West Nile virus outbreaks – Clinicians(DOH, 2005; DOH, n.d.)

WNVFor Your Information

For Mosquito control…

If you find a dying bird…o Contact

If you find a dead bird… o Do not touch it by bare hand o Report to

o For pick-up of dead animal… For any questions/concerns about WNV…

Animal Disease Control Program

Phone: (202) 535-2323DC Animal ShelterPhone: (202) 576-

6664West Nile Virus Call

CenterPhone: (202) 535-2323

Call #311

Department of HealthPhone: (877) 672-2174

Office Hours: M - F 8:15 am – 4:45 pm www.doh.dc.gov

WNVReview

Mosquito-borne disease Birds are the primary host of WNV Mosquitos are the vector of WNV

o become infected through infected birds through biteo transmit the infection to humans through bite

Usually mild, flu-like symptoms for a few days Neuroinvasive WNV is rate and sever condition People older than 50 years are at higher risk!! Primary prevention for WNV is use of Mosquito

repellant! Control of WNV is clearing mosquito’s breeding site! Contact DOH @(877) 672-2174 for questions &

Concerns

References Centers for Disease Control and Prevention. (2005). What you need to know about mosquito

repellant. Retrieved January 14, 2013,from CDC website: http://www.cdc.gov/ncidod/dvbid/westnile/mosquitorepellent.htm

Centers for Disease Control and Prevention. (2012a). Fight the bite! Retrieved January 14, 2013, from CDC website: http://www.cdc.gov/ncidod/dvbid/westnile/index.htm

Centers for Disease Control and Prevention. (2012b). West Nile virus: Epidemiologic information for clinicians. Retrieved January 14, 2013,from CDC website: http://www.cdc.gov/ncidod/dvbid/westnile/clinicians/epi.htm

Centers for Disease Control and Prevention. (2012c). West Nile virus: What you need to know. Retrieved from http://www.cdc.gov/ncidod/dvbid/westnile/wnv_factSheet.htm

Department of Health. (2012a). Controlling and repelling mosquitoes. Retrieved January 14, 2013, from DOH website: http://doh.dc.gov/node/164922

Department of Health. (2012b). West Nile virus. Retrieved January 14, 2013, from DOH website: http://doh.dc.gov/service/west-nile-virus

Department of Health. (n.d.). West Nile virus brochure [pdf format]. Retrieved January 14, 2013, from DOH website: http://doh.dc.gov/sites/default/files/dc/sites/doh/publication/attachments/West-Nile-Virus-Brochure.pdf

References Department of Health and Mental Hygiene. (2013). West Nile virus. Retrieved January 19, 2013,

from DHMH website: http://ideha.dhmh.maryland.gov/oideor/czvbd/sitepages/west-nile.aspx#

Florida Department of Agriculture & Consumer Services. (2012). Frequently asked questions about permethrin [pdf format]. Retrieved January 19, 2013, from http://www.flaes.org/pdf/Permethrin%20QA%20final%208-25-11.pdf

Howell, T. Jr. (August, 2012). D.C. resident contracts West Nile virus. Times. Retrieved January 14, 2013 from http://www.washingtontimes.com/news/2012/aug/22/dc-resident-contracts-west-nile-virus/

Huhn, G. D., Sejvar, J., Montgomery, S. P., & Dwokin, M. S. (2003). West Nile virus in the United States: An update on an emerging infectious disease. American Family Physician, 68(4), 653-661. Retrieved from AAFP website: http://www.aafp.org/afp/2003/0815/p653.html

Medical News Today. (2012, September). West Nile virus, Worst year ever says CDC, USA. Retrieved January 19, 2013, from MNT website: http://www.medicalnewstoday.com/articles/249974.php

National Center for Biotechnology Information, U.S. National Library of Medicine. (2012). West Nile virus. Retrieved February 1, 2013 from PubMed Health website: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0004457/

References Rappole, J. H., Derrickson, S. R., & Hubálek, Z. (2000, August). Migratory birds and spread

of West Nile virus in the Western Hemisphere. Emerging Infectious Disease, 6(4). Retrieved from CDC website: http://wwwnc.cdc.gov/eid/article/6/4/00-0401_article.htm

Salinas, J.D., & Steiner, M.L. (2012). West Nile virus. Retrieved January 19, 2013, from Medscape Reference website: http://emedicine.medscape.com/article/312210-overview

Ticinfo.com. (2000). Permethrin repellant. Retrieved January 19, 2013, from http://www.tickinfo.com/permethrin.htm

U.S. Environmental Protection Agency. (2012a). Alphabetical list of pesticide fact sheets. Retrieved January 14, 2013, from EPA website: http://www.epa.gov/pesticides/factsheets/alpha_fs.htm

U.S. Environmental Protection Agency. (2012b). Joint statement on mosquito control in the United States from the U.S. Environmental Protection Agency (EPA) and the U.S. Centers for Disease Control and Prevention (CDC). Retrieved January 19, 2013, from EPA website: http://www.epa.gov/pesticides/health/mosquitoes/mosquitojoint.htm

References U.S. Environmental Protection Agency. (2012d). The insect repellent DEET.

Retrieved January 14, 2013, from EPA website:http://www.epa.gov/pesticides/factsheets/chemicals/deet.htm

Washington Examiner. (2012, September). West Nile virus kills D.C. resident. Retrieved from: http://washingtonexaminer.com/west-nile-virus-kills-d.c.-resident/article/2507261#.UPvmR2_hrZI

Winn, W. C., Jr., Allen, S. D. A., Janda, W. M., Koneman, E. W., Procop, G. W., Schreckenberger, P. C., & Woods, G. L. (2006). Koneman’s color atlas and textbook of diagnostic microbiology (6th ed.). Philadelphia: Lippincott Williams & Wilkins.

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20, 2013, from EIPHD website: http://www.phd7.idaho.gov/Infectious%20Disease/WNV/wvnmain.html

Centers for Disease Control and Prevention. (2007). Number of West Nile virus neuroinvasive disease cases, by week of illness onset -- United States, 2007 [Figure]. Retrieved from Medscape website: http://www.medscape.com/viewarticle/577372

Centers for Disease Control and Prevention. (2012). West Nile virus (WNV) activity reported to ArboNET, by county, United States, 2012 (as of December 11,2012)[Figure]. Retrieved from CDC website: http://www.cdc.gov/ncidod/dvbid/westnile/Mapsactivity/surv&control12MapsAnybyCounty.htm

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