West Nile Virus & Eastern Equine Encephalitis By: Anna Ngo HLTH 107 December 11, 2008

What is it? They are arthropod-borne diseases, or “arboviruses” because they are mainly transmitted by arthropods which include mosquitoes and ticks Both lead to encephalitis which is an inflammation of the brain

Transmission Transmitted between birds and mosquitoes (bidirectional), but not human to human Birds = reservoir host Mosquitoes = vectors Incidental Host = humans and horses

Transmission (continued) Reservoir Host (birds) Directly or indirectly transmits a pathogen while being virtually immune to its effects Vectors (mosquitoes) Organism that carries the virus from one animal to another Incidental Host (humans & horses) An organism that is not capable of transmitting the virus to another organism or back to the mosquito (Sfakianos 38-42)

Facts and Figures As of November 18, 2008, there have been a total of 1301 cases of West Nile virus, 34 have which resulted in death.  Of the 1301 cases reported, 602 (46%) were reported as West Nile meningitis or encephalitis while 50% were reported as West Nile fever Between 1964-2007, there have been 254 confirmed or probable cases of EEE in the United States.  There has never a confirmed or probable case of EEE in the state of Vermont. (Center for Disease Control and Prevention 2008)

Treatment There are currently no specific treatments for these infections since antibiotics are ineffective against viruses. In milder cases, the fever and aches tend to pass over on their own. However, in more severe cases when the patient has severe headaches, a high fever, stiff neck, loss of consciousness, or muscle weakness.

Prevention Around the House - Empty any containers that can hold standing water (children’s toys, old tires, gutters etc.) - Change the water in birdbaths and fountains at least once a week - Change outdoor lights to yellow lights (mosquitoes are less attracted to yellow lights than other types) - Make sure the windows around the house are “bug tight” - Avoid going outside during peak mosquito hours (dusk and evening) - Wear dark, long sleeved clothing - Wear insect repellent (DEET provides the longest lasting protection)

Use of Pesticides In order to control the mosquito population during mosquito season (April to October), many public health officials resort to pesticides. Pros: - Decreases mosquito populations - Decreased chance of contracting the West Nile virus and EEE - Convenient Cons: - Pesticide resistance - May do more harm to humans and other animals than other forms of mosquito control - Expensive form of control - Adverse health effects in the workers who apply the pesticides

References Sfakianos, J. N., (2005). Deadly diseases and epidemics: West Nile virus. Philadelphia: Chelsea House Publishers. American Council on Science and Health. (2004). West Nile virus: Pesticide fears bite. Retrieved December 7, 2008 from http://www.acsh.org/factsfears/newsID.327/news_detail.asp. Centers for Disease Control and Prevention. (2006). West Nile virus: What you need to know. Retrieved 7, 2008 from http://www.cdc.gov/ncidod/dvbid/westnile/wnv_factsheet.htm. Centers for Disease Control and Prevention. (2008). Eastern Equine Encephalitis fact sheet. Retrieved December 7, 2008 from http://www.cdc.gov/ncidod/dvbid/arbor/eeefact.htm. Competitive Enterprise Institute. (2004). Pesticides and the West Nile virus: An examination of environmentalist claims. Retrieved December 7, 2008 from http://cei.org/gencon/025,03893.cfm. Directors of Health Promotion and Education. Eastern Equine Encephalitis. Retrieved December 7, 2008 from http://www.dhpe.org/infect/equine.html. Office of Health and Human Services. (2007). Frequently asked questions about Anvil spraying to reduce risk of Eastern Equine Encephalitis. Retrieved December 7, 2008fromhttp://www.mass.gov/?pageID=eohhs2terminal& L=\6&L0=Home&L1=Consumer&L2=Community+Health+and+Safety& L3=Environmental+Health&L4=Environmental+Exposure+Topics&L5 =Pesticide+Spray&sid=Eeohhs2&b=terminalcontent&f=dph_environmenta l_c_mosquito_anvil_application_faqs&csid=Eeohhs2 U.S. Environmental Protection Agency. (2007). About mosquitoes. Retrieved December 7, 2008 from http://www.epa.gov/pesticides/health/mosquitoes/about_mosquitos.htm. U.S. Environmental Protection Agency. (2007). Mosquito control. Retrieved December 7, 2008 from http://www.epa.gov/pesticides/health/mosquitoes/. West Nile Virus Facts. West Nile virus facts. Retrieved December 8, 2008 from http://www.westnilevirusfacts.org/wnvfacts.html.