West Nile Virus Update

1. West Nile Virus Update John D. Hopkins, Ph.D. Extension Urban Entomologist

2. What is West Nile Virus? “arbovirus” - derived from phrase “arthropod-borne.” Flavivirus Infects birds, humans, other vertebrates (Africa, E. Europe, W. Asia, Middle East.) Closely related to St. Louis encephalitis virus found in US.

4. West Nile Virus Wild and domestic birds - primary host. Spreads from birds to man and other animals via mosquitoes feeding on an infected bird and then biting another host. Mosquitoes that transmit WNV and SLE usually prefer to bite birds. Human infections with these mosquito-borne viruses are very rare and can be prevented by taking simple measures to avoid mosquito bites.

6. Symptoms: WN fever / encephalitis Usually 3-15 days after bite of infected mosquito. Most people infected with WNV have no symptoms Or - may have mild flu-like illness (West Nile Fever) fever, headache, and body aches completely recover (few days). Or - serious illness with inflammation of brain (WN Encephalitis) particularly at risk are the elderly (> 50 yrs old) high fever, severe headache, nausea, stiff neck, confusion, muscle weakness, paralysis, disorientation, convulsions, coma, and rarely, death. < 1% of humans infected with WNV will develop serious illness.

7. WNV Transmission Risk

8. Treatment: WN fever / encephalitis No specific treatment, medication, or cure for illnesses caused by West Nile virus Symptoms and complications of the disease can be treated No vaccine currently available for humans Vaccine available for horses (conditionally licensed by the USDA in August 2001). Symptoms in horses are similar to symptoms found in horses infected with EEE.

9. History of West Nile Virus 1st discovered West Nile District of Uganda 1937 Israel - 1951-1954, 1957 large outbreak, 2000 France – 1962, 2000 South Africa - 1974 Romania - 1996 Italy - 1998 Russia - 1999

10. History of West Nile Virus WNV 1st recognized in Western Hemisphere summer 1999 outbreak occurred in New York City area 62 people diagnosed with WNV 7 deaths.

11. How was WNV introduced into US? Origin of WNV in US unknown, but most closely related genetically to strains found in Middle East. Possible Pathways of Introduction: Infected human host Human-transported vertebrate host Legal or Illegal Human-transported vector(s) Storm-transported vertebrate host (bird) Intentional introduction (terrorist event)

12. History of West Nile Virus (continued) WNV spread in 2000: District of Columbia and 12 states (CT, DE, MD, MA, NH, NJ, NY, NC, PA, RI, VT, and VA) 21 human cases WN encephalitis (NY, NJ, and CT) with 2 deaths

13. History of West Nile Virus (continued) Sept. 2001: 4 blue jays with WNV (Union, Saline, and Sebastian Co’s in AR) No human WNV cases yet diagnosed in AR

14. History of West Nile Virus (continued) October 2001: WNV present in 27 states and Canada

15. WNV-Positive Dead Birds, 2001* In 2001, more than 7300 WNV-positive birds were reported from 27 states and DC which are shown here in red. Infected birds were reported from 328 of the 358 counties that reported any activity in 2001. Most of the birds were reported from the two regions that reported activity in 1999 and 2000 – the New England and Mid-Atlantic regions. But, for the first time ever, infected birds were reported from the South Atlantic, the East South Central, the West South Central, the East North Central and the West North Central regions. …. With more than 2500 birds reported from the South Atlantic region.In 2001, more than 7300 WNV-positive birds were reported from 27 states and DC which are shown here in red. Infected birds were reported from 328 of the 358 counties that reported any activity in 2001. Most of the birds were reported from the two regions that reported activity in 1999 and 2000 – the New England and Mid-Atlantic regions. But, for the first time ever, infected birds were reported from the South Atlantic, the East South Central, the West South Central, the East North Central and the West North Central regions. …. With more than 2500 birds reported from the South Atlantic region.

16. History of West Nile Virus (continued) 2001 - human infection with WNV: 10 states 66 cases 9 deaths.

17. Human WNV Disease Cases, 2001* In 2001, 66 human illnesses attributed to WNV were reported to ArboNET. Of these, 64 were severe neurologic illnesses in which people were hospitalized while 2 appeared to have West Nile fever. And, just to let you know, we are still working with cooperators to sort out a few more possible cases. So, this number may change in the coming weeks. Most human cases were reported from the Mid Atlantic region which included NY, NJ, and PA where 30 human illnesses were reported. The south Atlantic region reported 24 human cases of illness and the New England region reported 9 human cases. These 66 cases were reported from 39 counties in 10 states … shown here in red.In 2001, 66 human illnesses attributed to WNV were reported to ArboNET. Of these, 64 were severe neurologic illnesses in which people were hospitalized while 2 appeared to have West Nile fever. And, just to let you know, we are still working with cooperators to sort out a few more possible cases. So, this number may change in the coming weeks. Most human cases were reported from the Mid Atlantic region which included NY, NJ, and PA where 30 human illnesses were reported. The south Atlantic region reported 24 human cases of illness and the New England region reported 9 human cases. These 66 cases were reported from 39 counties in 10 states … shown here in red.

18. History of West Nile Virus (continued) 2002: WNV activity spread to most states

19. History of West Nile Virus (continued) 2002: 3242 human cases 176 deaths

20. What’s being done about WNV in AR? CDC provided grant to Arkansas Dept. of Health to enhance WNV and other arbovirus surveillance Human arbovirus testing at the ADH Laboratory Equine testing - Arkansas Livestock and Poultry Commission Lab. Mosquito pool testing – collected by ADH Environmental Specialists & tested at Arkansas Livestock and Poultry Commission Lab. Dead bird surveillance - tested at Arkansas Livestock and Poultry Commission Lab.

21. AR Mosquito Surveillance, 2002

22. WNV Positive Mosquitoes, 2002

23. AR Bird Surveillance, 2002 426 positives / 2116 samples from 58 Counties

24. 2002 Positive Horses108 WNV, 27 EEE

26. What’s being done about WNV in AR? AR Governor authorized release of $1,000,000 to County Judges to assist counties with mosquito abatement to control WNV. Required partnership with Cooperative Extension Service and Department of Health Environmental Specialists for technical assistance and advice Funds restricted for purchase of: Mosquito larvicides Hand/backpack equipment for larvicide application WNV education materials

27. What’s being done about WNV in AR? Univ. of AR, Cooperative Extension Service prepared Fact Sheets: FSA7059 – Mosquito Control Around the Home and in Communities FSA7060 – Developing a Community Mosquito Abatement Program

28. How Do You Protect Yourself From WNV?

29. Practical Risk Reduction Practices: Minimize time spent outdoors when mosquitoes are most active (usually dusk and dawn) If you go out when mosquitoes are active, cover up by wearing shoes, socks, long-sleeved shirts, and long pants Consider using a mosquito repellant containing DEET (N,N-diethylmethyl-meta-toluamide) on exposed skin. Carefully read and follow label directions Make sure your home has tight-fitting screens that keep mosquitoes out All mosquitoes need standing water for the first stages of development. Eliminate stagnant and standing water around your home by disposing of any discarded containers, tires, plant pots, etc. that can hold water. In the spring, inspect rain gutters and downspouts and remove any leaves and other debris. Stack wheelbarrows, tubs, buckets, barrels, boats or canoes, etc. upside down so that water does not accumulate in them. Empty bird baths, lily ponds, small wading pools, etc. at least once a week. Properly maintain backyard swimming pools. Cover any pool not in use so rainwater and leaves do not accumulate. Be sure the cover does not hold pockets of water.

30. Future of West Nile Virus? The continued expansion of West Nile virus in the United States indicates that it is permanently established in the Western Hemisphere.

34. Other Encephalitis Diseases in AR Eastern Equine Encephalitis (EEE) humans, horses, pheasants, and emus very susceptible. only a few human cases of EEE ever reported in AR infected children most likely to have severe illness or die EEE considered the most severe arboviral encephalitis human fatality rate approaches 70% individuals who recover frequently have permanent, disabling side effects recent sporadic outbreaks in horses and emus in AR EEE symptoms in horses: walk in circles, unbalanced, head droops and convulsion Emus infected with EEE will have bloody diarrhea no vaccine for routine use in humans but one is available for horses and emus and can prevent EEE if vaccinated regularly.

35. Other Encephalitis Diseases in AR St. Louis Encephalitis (SLE) SLE does not cause disease in animals strictly a human disease Large outbreaks of SLE have sporadically occurred throughout the US symptoms typically milder, with most people experiencing flu like symptoms Elderly are ones that are primarily affected AR experiences sporadic cases of SLE, most going unreported 1991 - largest recent outbreak in AR Pine Bluff - 28 hospitalized with five deaths all over the age of 60 2 cases of SLE were reported from Pine Bluff in 2001 with one being fatal.

43. Mosquito Control Suggestions for Around the Home Dispose of tin cans, plastic containers, ceramic pots or similar water-holding containers. Remove all discarded tires on your property. Drill holes in bottoms of recycling containers kept outdoors. Insure roof gutters drain properly and clean clogged gutters in the spring and fall. Turn over plastic wading pools and wheelbarrows when not in use. Change the water in bird baths. Clean vegetation and debris from the edges of ponds. Clean and chlorinate swimming pools, outdoor saunas and hot tubs. Drain water from pool covers. Use landscaping to eliminate stagnant water that collects on your property. Mosquito Control Suggestions for Around the Home Dispose of tin cans, plastic containers, ceramic pots or similar water-holding containers. Remove all discarded tires on your property. Drill holes in bottoms of recycling containers kept outdoors. Insure roof gutters drain properly and clean clogged gutters in the spring and fall. Turn over plastic wading pools and wheelbarrows when not in use. Change the water in bird baths. Clean vegetation and debris from the edges of ponds. Clean and chlorinate swimming pools, outdoor saunas and hot tubs. Drain water from pool covers. Use landscaping to eliminate stagnant water that collects on your property.Mosquito Control Suggestions for Around the Home Dispose of tin cans, plastic containers, ceramic pots or similar water-holding containers. Remove all discarded tires on your property. Drill holes in bottoms of recycling containers kept outdoors. Insure roof gutters drain properly and clean clogged gutters in the spring and fall. Turn over plastic wading pools and wheelbarrows when not in use. Change the water in bird baths. Clean vegetation and debris from the edges of ponds. Clean and chlorinate swimming pools, outdoor saunas and hot tubs. Drain water from pool covers. Use landscaping to eliminate stagnant water that collects on your property.