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West Nile Virus on the Rise Again, Leading to One Death in Illinois
Cases of West Nile Virus are beginning to increase as the summer ends, leading to illness and death across the United States that is exacerbated by environmental factors.
Last week, the Illinois Department of Public Health (IDPH) reported its first human case and West Nile virus (WNV) death since the beginning of 2022. The individual in their late seventies became ill at the beginning of August and was diagnosed with WNV at a CDC lab, passing away less than a month later.
Nationwide, a seasonal uptick in disease and death is now occurring as the summer comes to a close.
“This unfortunate first reported death of the year from West Nile virus in Illinois is a reminder that this disease poses a risk, especially to those who have weakened immune systems,” warned IDPH Director Sameer Vohra MD.
In the summer and fall of 2021, Arizona was inundated with its worst ever WNV outbreak, leading to 1,600 infections and 121 deaths. Research conducted by the National Oceanic Atmospheric Administration linked the magnitude of the outbreak to unusual monsoon-like weather conditions that supported mosquito breeding from June to September.
Zoonotic diseases like WNV are permanent public health concerns in the US, and their prevalence is likely to increase as climate change and warming temperatures make it more difficult for health authorities to control and predict the spread of disease. In the EPA’s most recent climate change indicator report, researchers estimate that the mild winters, droughts, and short periods of intense rainfall associated with climate change may lead to increased WNV in the future.
Public health efforts to address environmental health concerns and manage mosquito populations are successful at temporarily protecting from mosquito-borne diseases. However, despite a flattening of annual WNV cases since the early 2000s, some US states have still not been able to manage seasonal zoonotic disease outbreaks.
The African-derived zoonotic disease was first discovered in the United States in 1999, likely arriving in the country via an infected bird or mosquito. After the initial introduction, WNV spread around the New York City area, quickly establishing itself across the contiguous US and Canada. Just three years later, in the summer of 2002, the US saw the largest outbreak of WNV ever recorded anywhere, with 4,156 infections and 284 deaths. The infectious disease is now the most common cause of mosquito-borne disease in the US.
Currently, the Environmental Protection Agency (EPA) and CDC are working to monitor and quell the spread of mosquito-borne diseases, including WNV, by tracking diseases and providing localities with the resources to deal with environmental concerns that could lead to an outbreak.
