Signs and symptoms, epidemiology, treatment, prevention of WNV

1. West Nile Virus (WNV) Microbiology – Alison Lederer – Aurora University (Fall 2008)

2. CDC Cause Infection of West Nile virus during blood-feeding of Culex or Aedes mosquitoes West Niles virus under electronmicroscope Culex mosquito

3. 3 Possible Degrees Sub-Clinical: Fever Headache Fatigue Fatal: High fever Severe headache Nausea and vomiting Stiff neckSeizuresProfound muscle weakness Asymptomatic Signs and Symptoms Encephalitis: inflammation of the brain ViremicPeriod – 7 days

4. Treatment There is no cure for WNV Most treatments are aimed at retaining bodily function of fatally infected individuals Maintaining fluid levels (IV) Ventilator treatments Antibiotic injections to eliminate secondary and opportunistic diseases Vaccination for WNV is in research and development stages (Sfakianos 2005)

5. Transmission Mosquitoes Vector blood-feeding Instantaneous infection from simultaneous feeding Mosquito vertical transmission Culex mosquito Turdus migratorius (Kilpatrick 2007)

6. Transmission Birds Birds living past 8 days develop both specific and general defense to flaviviruses Horizontal transmission Culex mosquito Turdus migratorius (Kilpatrick 2007)

7. Transmission Culex mosquito Epizootic - nearly all birds and mammals become infected Culex pipiens has preferential feeding for Turdus migratorius Turdus migratorius (Kilpatrick 2007)

8. Transmission Turdusmigratorius found responsible for ∼60% of WNV-infectious mosquitoes in several regions The migration of Turdusmigratorius in the fall may cause greater mammalian and human infection Culex mosquito Turdus migratorius (Kilpatrick 2007)

9. Transmission Many possibilities exist to explain transmission of West Nile virus across continents including: Alien species introduction Culex incubation inside ships Transportation of incidentally infected organism Mutation allowing longer dormant viability

10. Host competence is not limited to birds (Kilpatrick 2007) Demographics The New York outbreak of killed great numbers of crows just before human infection (Sfakianos 2005)

11. Demographics 2008 1999 Multiple vectors, reservoirs, and hosts allowed West Nile to march all the way across the continental United States in less than a decade

12. Factors associated with WNV Infection Immune response Age (young and elderly) Genetic factors Unhealthy lifestyles Viral replication Rate of mutation Initial viral infection count Demographics Tomas Aragon, MD, DrPHCenter for Infectious Disease PreparednessUC Berkeley School of Public Health

13. Prevention www.health.alberta.ca The new way to BBQ?

14. Avoid high mosquito prevalent areas and times Prevention

15. Avoid high mosquito prevalent areas and times Remove or properly treat standing water sources that encourage mosquito breeding Prevention

16. Avoid high mosquito prevalent areas and times Remove or properly treat standing water sources that encourage mosquito breeding Prevention

17. Prevention

18. Avoid high mosquito prevalent areas and times Remove or properly treat standing water sources that encourage mosquito breeding Wear proper insect repellent and clothing when participating in outdoor activities Prevention

19. Prevention

20. Avoid high mosquito prevalent areas and times Remove or properly treat standing water sources that encourage mosquito breeding Wear proper insect repellent and clothing when participating in outdoor activities Become vaccinated when available Prevention

21. Prevention 1 2 3 4

22. Prevention 3 4 5 6

23. “Fun Facts” Some people may be genetically predisposed to getting milder versions of the disease . (Sfakianos 2005) WNV causes activation of both extrinsic and intrinsic apoptosis and it is currently theorized that inhibition of apoptosis may stop WNV from killing brain cells . (Kleinschmidt et. al. 2007) Infection can happen a decade before disease is present. (Sfakianos 2005)