West nile virus epidemiology and demographics
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Michael Maddaleni, B.S.
Overview
Incidence and Prevalence
West Nile virus is widely distributed across Australia, Middle East, Western Russia, Southwestern Asia, Africa and Southern Europe. Since 1999, a series of outbreaks, with virus likely of African origin, have increased the incidence of the disease across the previous countries.[1]
Across the western hemisphere, the virus was discovered in 1999 in new York City. The WNV was then spread across the continent, to the East cost of the US, in 4 years, and to Argentina in 6 years.[2][3]
Due to the fact that most cases of infection with the WNV are asymptomatic. West Nile fever is underreported, either because infected persons do not seek medical attention, or because they are not tested for the virus.[3] Between 1999 and 2013, 39 557 probable and confirmed cases of West Nile fever were reported to the CDC, from across the US.[4][2]
The outbreak of 2012, in which 2873 cases of neuroinvasive disease were reported, occurred during a period of increased mosquito infection rate. A possible explanation for this was the severe precipitation felt during the previous winter.[5][6]
Age
Age has not been noted to influence the development of West Nile fever following infection with the WNV. However, elderly patients have an higher risk of developing severe forms of the disease.[1][8]
Gender
The female gender is more prone to develop West Nile fever following infection with the WNV.[1][8]
Season
Geographical Distribution
US Disease Cases by State 2014
West Nile Virus by State 2014
Neuroinvasive Disease Incidence by State 2014
Due to the fact that infection with the WNV is often asymptomatic, the best approach to monitor incidence trends of the disease caused by the virus is by assessing the incidence of neuroinvasive disease, since its reporting is often adequate.[1] Despite this, during an outbreak, only 40% of the cases who presented with compatible meningitis or encephalitis were tested for infection with the virus.[9] Between 1999 and 2012, 16 196 cases of neuroinvasive disease by WNV, and 1549 fatalities were reported in the United Stated. The largest outbreaks of neuroinvasive disease were reported in 2002, with 2946 cases, in 2003, with 2866, and 2012, with 2873 cases.[4] Although the number varies every year, some areas of the US are more affected by this form of the disease, particularly Midwest states.[2]
During the outbreak of 2012, the incidence of West Nile virus neuroinvasive disease in Dallas was 7.30 per 100.000 persons.[5]
Neuroinvasive Disease Archives
References
- ↑ 1.0 1.1 1.2 1.3 May, F. J.; Davis, C. T.; Tesh, R. B.; Barrett, A. D. T. (2010). "Phylogeography of West Nile Virus: from the Cradle of Evolution in Africa to Eurasia, Australia, and the Americas". Journal of Virology. 85 (6): 2964–2974. doi:10.1128/JVI.01963-10. ISSN 0022-538X.
- ↑ 2.0 2.1 2.2 Lindsey NP, Staples JE, Lehman JA, Fischer M, Centers for Disease Control and Prevention (CDC) (2010). "Surveillance for human West Nile virus disease - United States, 1999-2008". MMWR Surveill Summ. 59 (2): 1–17. PMID 20360671.
- ↑ 3.0 3.1 Petersen LR, Hayes EB (2008). "West Nile virus in the Americas". Med Clin North Am. 92 (6): 1307–22, ix. PMID 19145778.
- ↑ 4.0 4.1 Petersen LR, Brault AC, Nasci RS (2013). "West Nile virus: review of the literature". JAMA. 310 (3): 308–15. doi:10.1001/jama.2013.8042. PMID 23860989.
- ↑ 5.0 5.1 Chung, Wendy M.; Buseman, Christen M.; Joyner, Sibeso N.; Hughes, Sonya M.; Fomby, Thomas B.; Luby, James P.; Haley, Robert W. (2013). "The 2012 West Nile Encephalitis Epidemic in Dallas, Texas". JAMA. 310 (3): 297. doi:10.1001/jama.2013.8267. ISSN 0098-7484.
- ↑ Goodman, Denise M.; Livingston, Edward H. (2012). "West Nile Virus". JAMA. 308 (10): 1052. doi:10.1001/2012.jama.11678. ISSN 0098-7484.
- ↑ 7.0 7.1 7.2 7.3 7.4 "Center for Disease Control and Prevention (CDC)".
- ↑ 8.0 8.1 Zou S, Foster GA, Dodd RY, Petersen LR, Stramer SL (2010). "West Nile fever characteristics among viremic persons identified through blood donor screening". J Infect Dis. 202 (9): 1354–61. doi:10.1086/656602. PMID 20874087.
- ↑ Weber IB, Lindsey NP, Bunko-Patterson AM, Briggs G, Wadleigh TJ, Sylvester TL; et al. (2012). "Completeness of West Nile virus testing in patients with meningitis and encephalitis during an outbreak in Arizona, USA". Epidemiol Infect. 140 (9): 1632–6. doi:10.1017/S0950268811002494. PMID 22123531.