Thomas McGee, L.C. 920 Main Street, Suite 1700 Kansas City, MO (816) * Toll Free (800) WEST NILE VIRUS

Transcription

1 Thomas McGee, L.C. 920 Main Street, Suite 1700 Kansas City, MO (816) * Toll Free (800) WEST NILE VIRUS

2 What Is West Nile Virus (WNV)? Potentially serious illness Seasonal epidemic in US Flares up in summer and continues into fall Virus that can infect Humans Birds reservoir hosts for virus, most infected survive Mosquitoes transmit from reservoir hosts to incidental hosts Horses 40% with WNV die Some other mammals no extensive illness with dogs and cats Typically spread to humans from bite of infected mosquitoes

3 What Is West Nile Virus (WNV)? Can also be transmitted by: Organ transplants Blood transfusions Breast milk From mother to fetus (Risk of these transmissions very low) WNV multiplies in person s blood system and crosses blood-brain barrier to reach brain

4 West Nile Virus Transmission Cycle

5 Are There Other Ways to Get WNV? No evidence of transmission: Animal to person Handling live or dead infected birds Caring for infected horse Eating game birds or animals Person to person Touching Kissing

6 Illnesses Caused By WNV Can cause West Nile Fever Fever Headaches Sometimes rash Can cause Neuroinvasive Disease (affects person s nervous system) West Nile encephalitis inflammation of brain West Nile meningitis inflammation of membrane around brain and spinal cord Acute Flaccid Paralysis inflammation of spinal cord causing sudden weakness in limbs and/or breathing muscles

7 Who Is At Risk? Outdoor workers when mosquitoes are biting Mostly July through September Mosquitoes most active from dusk to dawn Laboratory workers when handling WNV infected tissues or fluids Anyone living or working in areas where there are WNV infected mosquitoes Highest risk for severe illnesses from WNV infection: People above age 50 Those who have had organ transplants

8 Geographic Distribution of the West Nile Virus WNV first reported in eastern US in summer of 1999 By 2004, virus spread throughout US Common in Africa, West Asia, Middle East Cases in temperate zones occur mainly in late summer or early fall Can be transmitted year round in climates with mild temperatures

9 Geographic Distribution of the West Nile Virus

10 Geographic Distribution of the West Nile Virus

11 WNV Human Infections Kansas (As of December 28, 2010) Neuroinvasive Disease Cases (Encephalitis, Meningitis, Acute Flaccid Paralysis) Non-Neuroinvasive Disease Cases (West Nile fever) Total Cases Deaths Presumptive Viremic Donors* *People who had no symptoms at time of donating blood but whose blood tested positive In preliminary tests when screened for the presence of WNV.

12 Data On Infected Workers 2002 workers infected at turkey breeder farm 2004 workers infected at alligator farm Possibly through mosquito bites Possibly through contact or cut or scraped skin with infected feces Possibly swallowing or being splashed in eyes or mouth with contaminated material Possibly inhaling airborne virus from infected feces Many cases occur with people working in farming

13 Symptoms of WNV People typically develop symptoms 3-14 days after bitten by infected mosquito 80% of people infected show no symptoms Up to 20% have following symptoms lasting a few days or several weeks: Fever Headache Body aches Nausea Vomiting Swollen lymph glands Skin rash on chest, stomach and back

14 Symptoms of WNV Approximately 1 in 150 will develop severe illness and symptoms lasting several weeks (neurological effects may be permanent): High fever Headache Neck Stiffness Stupor Disorientation Coma Tremors Convulsions Muscle Weakness Vision Loss Numbness Paralysis

15 Where Are Mosquitoes Most Commonly Found? Standing bodies of water persisting for more than 4 days Stagnant bodies of water Pools Ponds Watering troughs Irrigation ditches Rain barrels Manure lagoons Weed, bushy, and wooded environments

16 Treatment of WNV No specific treatment for WNV infection For mild symptoms fever and aches they will pass on their own For severe symptoms hospital treatment with intravenous fluids and help with breathing may be needed Testing for WNV is available Testing of serum or cerebrospinal fluid No vaccine available to prevent WNV infection

17 Preventing WNV Recommendations For Employers Provide training describing how WNV is transmitted Reinforce knowledge about risks of WNV exposure and infection Stress to workers importance of reporting all work related injuries and illnesses Avoid having workers outdoors when mosquitoes most active dusk to dawn Recommend workers wear: Long sleeved shirts Long pants Socks

18 Preventing WNV Recommendations For Employers Eliminate as many sources of standing water from worksite as possible: Change water every 4-5 days in animal drinking troughs, birdbaths, other water containers Scrub sides of water containers to dislodge eggs Add aerator to ponds and water gardens to keep water circulating Add fish to ponds to eat mosquito larvae or adults Remove discarded tires or keep them dry and under cover

19 Preventing WNV Recommendations For Employers Turn over, cover, store or removed equipment such as tarps, buckets, barrels, wheelbarrows, and containers to prevent standing water Place drain holes in containers that collect water and cannot be discarded Clean out rain gutters Remove debris (leaves, twigs, trash) from ditches Fill in ruts and other areas that collect standing water

20 Preventing WNV Recommendations For Employees Use insect repellent on skin and clothing when mosquitoes are biting: DEET (more than 20% for longer protection) Picaridin Oil of Lemon Eucalyptus or PMD IR3535 Use Permethrin on clothing only Follow label directions for repellent use Do not apply pump or aerosol products directly to face Spray on hands and rub on face avoiding eyes and mouth Reapply as needed

21 Preventing WNV Recommendations For Employees Wear long sleeved shirts, long pants and socks Avoid handling dead animals when possible if you must handle: Use tools such as shovels to avoid direct contact Wear medical exam gloves Wear 2 pairs of gloves if one alone might tear If gloves not available, use a plastic bag