The West Nile Virus (WNV) is a mosquito-borne illness that has been reported in numerous components of the world, together with Africa, Europe, the Center East, North America, and West Asia. This widespread geographical distribution highlights the significance of understanding WNV transmission patterns and implementing efficient prevention methods.
Presence throughout continents
First recognized in Uganda in 1937, WNV has since unfold to a number of continents as a consequence of its means to contaminate completely different species of mosquitoes and birds. The first vectors for transmitting WNV are Culex mosquitoes which could be discovered globally. As contaminated birds migrate between areas or continents, they contribute to the unfold of this virus amongst native mosquito populations.
There are two most important lineages for the West Nile Virus:
- Lineage 1: Central and North Africa, Europe, and Australia
- Lineage 2: Southern Africa and Madagascar
Notable outbreaks
Americas
- In 1999, an outbreak occurred in New York Metropolis, marking the primary look of WNV in North America. Since then, it has change into broadly established from Canada down by way of Venezuela. Migratory birds are presumed to be the supply of this outbreak.
- Between 1999-2006: 23,000 instances (1,000 deadly) have been reported in the USA.
- In 2009: The primary fatality in South America (Mexico) was reported.
Europe
- From 1995-2015: 629 instances (82 deadly) of West Nile Fever have been reported within the Japanese Mediterranean Area (WHO-designated area)
- 2010: 375 instances (34 deadly) of human WNV instances reported by 17 nations within the Mediterranean area
- 2011: 282 instances reported
- 2012: 762 instances reported
- 2013: 395 instances reported
- 2014: 74 instances reported
- 2015: 108 instances reported
- 2017: 203 instances (26 deadly)
- From 2018-2023, a large-scale outbreak happened throughout Europe through the summer time months, with a number of nations reporting elevated instances in comparison with earlier years.
- Outbreaks have additionally been documented all through Africa and West Asia over current many years with various ranges of severity relying on components akin to native vector management measures and inhabitants immunity ranges.
Supply of outbreak information: GIDEON infectious ailments database. To get extra information on outbreaks, outbreak maps, nation notes, and extra, subscribe to the GIDEON app.
Excessive-risk populations for extreme sickness
Whereas anybody could be contaminated with West Nile virus (WNV), sure people are at a better danger of growing extreme sickness upon an infection. Older people and people with weakened immune methods, like organ transplant recipients or folks dwelling with HIV/AIDS, could also be extra in danger.
The chance of growing extreme illness from West Nile virus, together with West Nile neuroinvasive illness, will increase considerably in people aged 50 and above. As we age, our immune system turns into much less efficient in combating infections akin to WNV, thus making older adults extra prone to extreme sickness or issues. Consequently, they could expertise extra critical signs or issues if contaminated.
Immunocompromised people at elevated danger
Along with older adults, folks with weakened immune methods as a consequence of underlying well being situations or medical therapies additionally face an elevated danger of extreme sickness from WNV an infection. For instance, most cancers sufferers present process chemotherapy and people taking drugs that suppress the immune system have a decreased means to fight the virus successfully. Consequently, these populations might develop life-threatening issues akin to encephalitis or meningitis when uncovered to WNV.
