Malaria, dengue, and Eastern equine encephalitis are just a few of the mosquito-borne diseases that have prompted a flurry of alerts this summer.
According to a report published by the US Centers for Disease Control and Prevention on Thursday, West Nile virus, which is transmitted primarily through the bite of an infected mosquito, remains the leading cause of arboviral disease (viral disease spread by insects) in the continental United States.
The report provides an overview of the incidence of West Nile virus and other arboviral diseases in the United States in 2021.
Forty-nine states and the District of Columbia reported more than 3,000 domestic cases of arboviral disease, of which 2,911 were caused by West Nile virus. There were 2,099 hospitalizations of West Nile Virus patients, and 227 fatalities.
The national incidence rate of neuroinvasive West Nile virus disease, meaning the infection affected the nervous system, reached its greatest level since 2012, at 0.6 cases per 100,000 people, primarily due to an outbreak in Arizona.
Arizona Counties Lead in Neuroinvasive West Nile Cases, Highlighting the Mosquito Menac
In 2021, Maricopa, Pima, and Pinal counties in Arizona reported more than half of the nation’s identified neuroinvasive cases. Texas, with 130 West Nile Virus cases, was followed by Colorado, with 101 cases, California, with 96 cases, and Nebraska, with 69 cases.
West Nile spreads when mosquitoes bite infected birds and then humans, making avian and mosquito populations crucial components of West Nile surveillance for public health. Mosquitoes are the most lethal animal in the world because they transmit deadly diseases such as malaria, dengue, and West Nile, killing more humans than any other animal.
Although West Nile Virus was the leading cause of neuroinvasive arboviral disease in the United States in 2021, as in previous years, the La Crosse virus remained the leading cause of neuroinvasive arboviral disease in children, according to a new report from the CDC.
In Illinois, Indiana, Michigan, North Carolina, Ohio, Tennessee, West Virginia, and Wisconsin, 40 cases of La Crosse virus disease were reported in 2021, with 35 of those cases occurring in minors. All forty patients were hospitalized, but no one succumbed to the disease.
“Arboviruses continue to cause substantial morbidity in the United States, despite the fact that case numbers vary by year, virus, and region. Weather, the abundance of zoonotic hosts and vectors, and human behavior are all factors that can influence when and where epidemics occur, according to a new report by the CDC. This complexity makes it difficult to forecast the future locations and timing of cases and highlights the significance of surveillance to rapidly identify outbreaks and direct public health prevention efforts.
A handful of West Nile virus-related fatalities have been reported across the United States as of Thursday, including in Illinois, Nebraska, and Colorado. This year, a total of 247 cases of West Nile have been reported to the CDC, and that figure is rising.
According to public health and mosquito control experts, a historically wet winter and now a hotter summer are “pretty big” warning signs for West Nile virus in the Western United States, suggesting that residents should take precautions to prevent infections.
People can reduce their risk of contracting West Nile virus and other mosquito-borne illnesses by using insect repellent and donning long-sleeved shirts and trousers.
Earlier this month, Daniel Markowski, a technical counsel for the American Mosquito Control Association, stated that the number of mosquitoes that have emerged after the spring snowmelt is astronomical in many states, including Colorado, Utah, and California.
According to him, the presence of West Nile virus in mosquitoes in a number of districts indicates that “you’re at the right temperature, the right mosquito population, and the right time of year for localized outbreaks to occur.”
About 1 in 5 individuals infected with West Nile virus may develop a fever and other symptoms, but the vast majority do not. About 1 in 150 infected individuals develop a severe or sometimes fatal disorder affecting the central nervous system, such as encephalitis, which causes brain inflammation, or meningitis, which causes inflammation of the membranes that encircle the brain and spinal cord.
Source: CBS News