Due to several non-native disease-carrying mosquito species that have established an invasive habitat in urban and suburban areas of the US during the past 20 years, mosquito-borne disease has become a major public health threat in the country. Just three years ago, a number of Americans in Florida and Texas contracted the Zika virus, and the rate of West Nile infections has been steadily increasing in the US since the disease was introduced into the country two decades ago. This year, the mosquito-borne disease known as eastern equine encephalitis (EEE) has infected and killed an unprecedented number of people in the country. While no human EEE cases have occured in Louisiana this year, it should be known that urban-dwelling mosquito species in the state are capable of transmitting the disease to humans and certain animals.

According to the Centers for Disease Control and Prevention, the US sees seven EEE cases per year on average, but 2021 has already seen well over 30 EEE cases, and EEE season has not yet ended. In fact, the latest victim of EEE succumbed to the disease two days ago, which marked the 13th death to result from EEE infection this year in the US. So far, EEE has been reported in the northeast, around the Great Lakes and in Florida, but most states are home to mosquito species that are capable of transmitting the disease to humans. In many states, including Louisiana, mosquitoes frequently transmit EEE to dogs, cats and horses. In Louisiana, 16 horses were recently found to be infected with EEE, which public health officials in the state claim is an unusually high number of EEE infections. 

Mosquitoes acquire the microorganisms that cause EEE by consuming the blood of certain bird species. After feeding on infected birds, mosquitoes can then transmit the disease to humans through their bites. Uninfected mosquitoes can also acquire the disease by feeding on the blood of infected animals. This is why mosquitoes that can carry EEE are often referred to as “bridge vectors,” as they are solely responsible for exposing the bird-virus to healthy humans. Around 30 percent of those who contract EEE will die from the disease, and no vaccines exist for EEE. Also, no medical treatments have been demonstrated to slow the progression of EEE infection, and most people who contact the disease die from consequent brain swelling within a month or two following infection. Since EEE poses a serious public health threat in Louisiana during most of the year, residents should never leave home without first applying DEET repellent. Unfortunately, experts state that EEE cannot be eradicated from an area once local mosquitoes begin carrying the disease.

Do you worry about the possibility of contracting EEE from mosquito bites?