Arizona Mosquitos Now Carry West Nile Virus Year-Round

The mosquito-borne West Nile Virus first appeared in Arizona in 2003. According to new research, it’s clear that the possibly life-threatening virus is here to stay.

Northern Arizona University (NAU) worked with the Translational Genomics Research Institute (TGen) to study the how the West Nile Virus moves throughout the southwestern United States using algorithmic modeling. In order to generate the patterns of the virus’ spread, researchers analyzed the virus on a genetic level, harvesting it directly from Arizona mosquitos. Researchers were able to conclude that there is a high probability that Arizona is now permanently home to mosquitos carrying this virus. 

When the virus first arrived in Arizona just four years after it appeared in the United States, it was probably brought by migrating birds. This new research has shown that the state’s warmer climate allows for birds and mosquitos to carry this disease year-round in Arizona. In most states, this virus that is responsible for about 1,000 deaths often is less active in the colder winter months. However, Arizona’s temperatures stay warm enough that the virus can thrive year-round.

The mosquitos tested for this study originated from more than 700 different locations around the Phoenix metro area. By studying the genetic material of the virus, researchers found that there are two strains of the virus that circulate around Maricopa county.

West Nile Virus is a disease that can be deadly, but most people do not even know that they have contracted the virus. 20 percent of those who are infected by the virus after being bitten by a mosquito will experience symptoms such as fever and nausea. There is a far smaller chance that the disease can spread to the brain, becoming much more serious than the average case of West Nile Virus. There are no known treatments or vaccines available for the disease, but there are ways it can be prevented. Using bug repellant sprays and making sure arms and legs are covered outdoors can help prevent mosquito bites and West Nile Virus infections.