ENVIRONMENTAL HEALTH PRESENTATION
WEST NILE VIRUS AND YOU
PRESENTED BYDARLINGTON ETUMNI, MPH
WALDEN UNIVERSITYPUBH-6165 : ASPECT OF
ENVIRONMENTAL HEALTH: LOCAL TO GLOBAL
INSTRUCTOR: DR. REBECCA HEICKWINTER QUARTER, 2010
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Objectives
At the end of the presentation, I will have refreshed your minds on
- What West Nile virus is- The signs and symptoms and how to
detect it- How it is contracted and transmitted- Who is at risk- How it can be treated, prevented and
controlled and- What the governments are doing about it
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West Nile Virus
What is it?West Nile virus (WNV) is a viral disease - It is transmitted through the bite of a mosquito
- It is a flavivirus and belongs to the Flaviviridae family- The most widely distributed Flavivirus worldwide (WHO, 2010)
ReferenceWorld Health Organization (2010). Vector-Borne Viral Infections: West Nile Virus. Retrieved on January 08, 2010 from http://www.who.int/vaccine_research/diseases/vector/en/index3.html
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Definition continued
- First discovered in 1937 in Uganda (PHAC, 2004)
- It is now a global disease found in many countries- First appeared in U.S and Canada in 1999 and 2002 respectively (PHAC, 2004; Medline Plus, 2008)References.
MedlinePlus (2008). West Nile Virus. Retrieved on December 22, 2009 from http://www.nlm.nih.gov/medlineplus/ency/article/007186.htm
Public Health Agency of Canada (2009). Infectious Diseases: West Nile Virus. Retrieved on December 22, 2009 from http://www.phac-aspc.gc.ca/wn-no/gen-eng.php?option=print
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How is it transmitted?
- Mosquitoes that feed on the blood of infected birds bite humans, horses and other mammals.
- Closely related to Yellow fever, Dengue fever and St. Louis encephalitis (PHAC, 2009)
- Other animals like dogs, cats, horses, birds, etc can also be infected by the virus
Reference
Public Health Agency of Canada (2009). Infectious Diseases: West Nile Virus. Retrieved on December 22, 2009 from http://www.phac-aspc.gc.ca/wn-no/gen-eng.php?option=print .
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Transmission continued
- About 140 different species of birds have been found to carry the virus (WHO, 2010).
- Through blood transfusion and organ/tissue transplants though, the chances are very low - It can also be passed to unborn babies through pregnancy as well as breast milk.
Reference
World Health Organization (2010). Vector-Borne Viral Infections: West Nile Virus. Retrieved on January 08, 2010 from http://www.who.int/vaccine_research/diseases/vector/en/index3.html
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Transmission continued
- Through infected needles or cuts.
- No evidence of transmission from animals to humans
- Also no evidence that infection can be contracted by touching or kissing an infected person or being around a health care worker (CDC, 2009; PHAC 2009).
References.Public Health Agency of Canada (2009). Infectious Diseases: West Nile Virus. Retrieved on December 22, 2009 from http://www.phac-aspc.gc.ca/wn-no/gen-eng.php?option=print
Center for Disease and Prevention (2004). West Nile Virus. Retrieved on December 22, 2009 from www.cdc.gov/westnile
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Incidence and Prevalence.
- As at the end of 2009, there were 663 cases reported in the U.S (CDC, 2009).
-Of this number, 335 cases (51%) reported symptoms of meningitis and encephalitis (CDC, 2009).
- 302 cases or 46% reported fever and 26 cases or 4% had unspecified symptoms (CDC, 2009).Reference.
Center for Disease and Prevention (2009). West Nile Virus: Statistics, Surveillance, and Control. Retrieved on December 22, 2009 from http://www.cdc.gov/ncidod/dvbid/westnile/surv&controlCaseCount09_detailed.htm
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Incidence and Prevalence continued
-In Canada there were 8 cases reported in 2009. 25% of the cases had neurological symptoms while the other 75% had non-neurological symptoms (PHAC, 2009).
- No deaths were reported.
Reference.
Public Health Agency of Canada (2009). West Nile Virus National Surveillance Report. Retrieved on December 22, 2009 from http://www.phac-aspc.gc.ca/wn-no/gen-eng.php?option=print.
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Epidemiology- How it all started
- WNV is of African, Asian, European and Australian origin
- First outbreak in humans recorded in 1990 in Europe and Mediterranean with largest outbreak in Russia, Romania and Israel.
- First recorded in the U.S in 199910
Epidemiology continued
- Largest outbreak in Western Hemisphere recorded in 2002 (CDC, 2004).
- The virus has now been reported in 44 states including the District of Columbia.
References.Center for Disease and Prevention (2004). West Nile Virus. Retrieved on December 22, 2009 from www.cdc.gov/westnile
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When is exposure greatest?
- Infection is highest from April to October.
- Visiting areas or living in countries where the virus has been found increases your risk of being infected.
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Who is at risk?
You may be at risk of contracting the virus if you are:
- elderly which includes those 50 years and above
- have a chronic disease like cancer, diabetes, heart disease (PHAC, 2009).
Reference
Public Health Agency of Canada (2009). Infectious Diseases: West Nile Virus. Retrieved on December 22, 2009 from http://www.phac-aspc.gc.ca/wn-no/gen-eng.php?option=print
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Risk continued
- pregnant
- nursing
-spending a great deal of time outside
- immunocompromised like in HIV and transplant patients, those on chemotherapy
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How do you know you are sick?- Most people (about 80%) do not develop any symptoms when infected and do not get sick. - Infection takes about 2 to 14 days to develop.- Mild symptoms occur in 20% of cases and include - fever
- headache and body aches - nausea and vomiting - mild skin rash
- swollen lymph glands
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Signs and symptoms continued
- Severe symptoms which occur in very few people include
- high fever - severe headache - stiff neck - difficulty swallowing - confusion
- muscle weakness and paralysis - lack of coordination and loss of consciousness - loss of vision, numbness. - in rare cases, it can lead to death
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What tests and exams can be done?Apart from the signs and symptoms, the following tests can done to
confirm if you have the virus or not;
- Complete blood count (CBC) (Medline Plus, 2008).
- Complete scan or MRI of the head (Medline Plus, 2008).
- Lumber puncture and cerebrospinal fluid (CSF) testing (Medline Plus, 2008).
- Polymerase chain reaction (PCR) (Medline Plus, 2008).
- Serology test which checks for antibodies in blood or CSF (most accurate test so far) (Medline Plus, 2008)
References.
MedlinePlus (2008). West Nile Virus. Retrieved on December 22, 2009 from http://www.nlm.nih.gov/medlineplus/ency/article/007186.htm
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How is West Nile virus treated?- No treatment is available for the
disease.
- Milder symptoms like fever and pain resolve on their own.
- In healthy persons, illness may last for weeks to months (CDC, 2004).
References.Center for Disease and Prevention (2004). West Nile Virus. Retrieved on December 22, 2009 from www.cdc.gov/westnile
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Treatment continued
- In severe infections, affected persons may end up in the hospital where they receive - supportive treatments like IV fluids (CDC, 2004). - nursing care and (CDC, 2004).
- help with breathing (CDC, 2004).
References.Center for Disease and Prevention (2004). West Nile Virus. Retrieved on December 22, 2009 from www.cdc.gov/westnile
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If in doubt?
If you think you have the West Nile virus
- seek immediate medical attention
- if you are breastfeeding or pregnant, talk to your doctor.
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Any vaccine available?
- No! there is no vaccine presently available for the virus.
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What can I do to protect myself and my family?
There are several things that you can do to protect yourself and your family from being infected with the virus and they are;
- avoid mosquito bites to prevent infections(CDC, 2004)
- ensure stagnant water is gotten rid of around your homes.References.Center for Disease and Prevention (2004). West Nile Virus. Retrieved on December 22, 2009 from www.cdc.gov/westnile
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Control and prevention continued
- ensure there are no clogs that could trap water
- use insect repellent that contains DEET or approved ingredients
- wear light colored clothes, protective clothings like long-sleeved shirts, pants and hats (PHAC, 2004)
Reference.
Public Health Agency of Canada (2004). Protect yourself from mosquito bites. Retrieved on December 22, 2009 from www.westnilevirus.gc.ca.
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Control and prevention continued
- ensure that door and window screens are in good order
- clear mosquito breeding sites around your surroundings
- take extra caution from dusk to dawn which are peak mosquito hours.
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What actions are being taken?
In Canada, Public Health Agency of Canada in collaboration with her partners are
- involved in West Nile virus surveillance across the country - ensuring that blood donated is free from West Nile virus - continuously testing for the virus
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Actions continued
- ensuring that the pesticides and insect repellents used are safe and effective - coordinating a national approach to the virus in collaboration with First Nations communities on reserves.
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Actions continued
In the United States, CDC is working states and local health department as well other partners to - develop a nation-wide database for easy information sharing - assist states in developing prevention and control programs
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Actions continued
- developing better test methods to enhance diagnosis - more test laboratories are been opened for virus - contentiously working with partners to develop vaccines (CDC, 2005)Reference
Center for Disease and Prevention (2005). West Nile Virus: Fact Sheet. Retrieved on December 22, 2009 from www.cdc.gov/westnile
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Where can I get more information?
- Health Canada: West Nile Virus Information website- http://www.westnilevirus.gc.ca- Division of Vector-Borne Infectious Diseases, U.S. Centers for Disease Control and Prevention (CDC) - www.cdc.gov/ncidod/dvbid/westnile
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Sources of information continued
- National Institute of Allergy and Infectious Diseases (NIAID),National Institutes of Health website – http//www3.niaid.nih.gov
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THE END
QUESTION ????
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References.
-Center for Disease and Prevention (2004). West Nile Virus. Retrieved on December 22, 2009 from www.cdc.gov/westnile
-Center for Disease and Prevention (2005). West Nile Virus: Fact Sheet. Retrieved on December 22, 2009 from www.cdc.gov/westnile
-Huhn, G. D et al (2003). West Nile Virus in the United States: An Update on an Emerging Infectious Disease. American Family Physician, 68(4), 653-659
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Reference continued
-MayoClinic.com (2008). West Nile Virus. Retrieved on January 10, 2010 from http://www.mayoclinic.com/health/west-nile-virus/DS00438/METHOD=print- MedlinePlus (2008). West Nile Virus. Retrieved on December 22, 2009 from http://www.nlm.nih.gov/medlineplus/ency/article/007186.htm
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Reference continued
- Public Health Agency of Canada (2009). Infectious Diseases: West Nile Virus. Retrieved on December 22, 2009 from http://www.phac-aspc.gc.ca/wn-no/gen-eng.php?option=print
- Public Health Agency of Canada (2009). West Nile Virus National Surveillance Report. Retrieved on December 22, 2009 from http://www.phac-aspc.gc.ca/wn-no/gen-eng.php?option=print.
- Public Health Agency of Canada (2004). Protect yourself from mosquito bites. Retrieved on December 22, 2009 from www.westnilevirus.gc.ca
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Reference continued
- WebMD (2008). West Nile Virus. Retrieved on January 08, 2010 from http://www.webmd.com/a-to-z-guides/west-nile-virus-topic-overview
- World Health Organization (2010). Vector-Borne Viral Infections: West Nile Virus. Retrieved on January 08, 2010 from http://www.who.int/vaccine_research/diseases/vector/en/index3.html
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