Understanding Eastern Equine Encephalitis (EEE) and its Deadly Consequences in New Hampshire
Mosquitoes are known carriers of various diseases, including the potentially deadly eastern equine encephalitis (EEE) virus. Recently, a man in New Hampshire fell victim to this virus, while several others in neighboring states have also been affected. The town of Plymouth in Massachusetts has taken proactive measures by closing its public parks between dusk and dawn to reduce the risk of people contracting the infection. So, what exactly is EEE, and how prevalent is it in the northeastern United States?
The Origins of EEE
Eastern equine encephalitis, or EEE for short, is a viral illness that can be transmitted to humans through mosquito bites. The virus responsible for EEE is known as the EEE virus, or EEEV. The name “equine” in EEE comes from the fact that horses can also be infected by this virus. In fact, EEE was first identified among horses in Massachusetts in 1831. Human cases of the disease were not documented until about a century later. Since then, sporadic cases and clusters of infections have occurred, primarily along the Atlantic and Gulf coasts during the summer months. While EEE is considered rare, it is endemic to the United States.
In recent years, the number of EEE cases reported annually has ranged from one to 15. However, 2019 saw a significant spike with 38 cases reported nationwide. The reasons behind this sudden increase remain unclear. This year, several states, including New Hampshire, Vermont, Massachusetts, and New Jersey, reported their first cases of EEE in several years. Additionally, a person was hospitalized in Wisconsin after contracting the virus in a New England state. To date, six cases have been reported in 2024, with one resulting in a fatality. It is important to note that there may be a delay in reporting cases to the Centers for Disease Control and Prevention (CDC) as each case must be confirmed.
Transmission and Symptoms of EEE
The EEE virus is primarily spread by the mosquito species Culiseta melanura, which first infects birds before transmitting the virus to other mosquito species, including those that feed on mammals such as horses and humans. It is crucial to understand that EEE cannot be transmitted from person to person, or from horses or birds to humans. Most people who are exposed to the virus through a mosquito bite do not exhibit any symptoms. However, those who do become ill may experience fever, chills, body aches, joint pain, or in more severe cases, the virus may invade the central nervous system, affecting the brain and spinal cord.
Individuals with the febrile form of EEE typically recover within one to two weeks without any long-term complications. However, when the virus progresses to the neuroinvasive form, which affects the tissues surrounding the brain and spinal cord, it can be fatal in approximately one-third of cases. Less than 5% of febrile cases advance to the neuroinvasive stage, making severe cases rare. Symptoms of neuroinvasive EEE can include fever, headache, vomiting, diarrhea, seizures, behavioral changes, drowsiness, and even coma. Survivors of neuroinvasive EEE may experience long-term physical or mental disabilities, with many ultimately succumbing to complications within a few years.
Prevention and Treatment of EEE
Currently, there is no specific treatment or vaccine available for EEE. Individuals with the neuroinvasive form of the disease may require hospitalization for supportive care, such as intravenous fluids and pain management. Prevention remains the best course of action against EEE, with the CDC recommending the use of insect repellent, wearing protective clothing, and eliminating standing water sources around the home to reduce mosquito breeding grounds. Installing screens on windows and doors, as well as using air conditioning, can help keep mosquitoes out of living spaces.
Some states have implemented insecticide spraying in areas where the EEE virus is likely to spread to humans. These measures target locations where the virus has been detected in mosquitoes that bite mammals, including horses, as well as areas frequented by humans. While the number of reported EEE cases in 2024 has not been unusually high, health authorities emphasize the importance of mosquito-bite prevention and urge healthcare providers to remain vigilant in recognizing and treating the disease.
In conclusion, understanding the risks associated with EEE and taking proactive measures to prevent mosquito bites are crucial in protecting oneself from this potentially deadly virus. Stay informed, stay vigilant, and prioritize your health and well-being in mosquito-prone areas. Remember, prevention is key in combating EEE and safeguarding your community from its devastating consequences.
