Mosquito-Borne Diseases Initially Masquerading as Summer Flu

James Thompson, MD Health Pro
  • Depending on where you are and where you've traveled, a summer fever, headache and body aches may signal more than a case of the flu this year. The United States has not been a hotbed for mosquito-borne illnesses through the years but three viruses carried by these blood-sucking insects are gaining national attention.



    Here’s what you need to know about them:

    West Nile Virus (WNV)

    Many are familiar with this infectious virus from several years of media attention. Sixteen states have reported WNV infections so far this year.  Another eighteen states have identified birds with the virus. WNV is not transmitted from person to person, or animal (such as infected birds or horses) to person with respect to casual contact. Rarely, transmission has occurred from organ transplant, blood transfusion or from mother to child during pregnancy, delivery or breastfeeding.

    Add This Infographic to Your Website or Blog With This Code:



    According to the U.S. Centers for Disease Control (CDC) most people never realize they have the infection because of mild symptoms, no different from the flu or common cold. But twenty percent of the time people will experience fever, headache, body aches, diarrhea, and vomiting. Less than one out of a hundred may suffer severe brain swelling as a result of encephalitis (inflammation of the brain).


    Signs of encephalitis include: severe headache, high fever, stiff neck, confusion, tremor, seizure, paralysis and coma.

    Although overall mortality from West Nile Virus infection is uncommon, ten percent of those who have neurologic ailments associated with it will die. Most people are fine after a couple of weeks but some will continue to have bothersome aches or pains for several months.



    Chikungunya Virus (CV)

    Chikungunya Virus is not as deadly as the other two discussed in this posting but has not, prior to this year, been found, in mosquitoes, in mainland United States. CV has been more of a concern in recent weeks because of two cases in Florida which involved individuals who had not recently traveled outside of the United States. Over 600 cases of CV have been reported this year, mostly from travelers to the Caribbean and Pacific. Thirty states have reported cases of CV (all from people who had been traveling except for Florida)



    Symptoms of CV usually occur within a week of being bitten and include fever and joint pain but may also be accompanied by muscle pain, headache, joint swelling or skin rash. Though death is uncommon and most people recover within a week, the joint and muscle pains can be severe and disabling. Some may continue to have joint pain for several weeks.



    Eastern Equine Encephalitis Virus (EEE)

    EEE infections have been reported from a handful of states for several years but no human cases have been reported so far this year. States along the Gulf and Atlantic coasts, and Great Lakes regions account for the majority EEE cases over the last several years but only a few human infections occur in America each year. So far it’s only been reported in Massachusetts (animal vector). Unfortunately death rates are up to 33% for those who get the infection.

  • Symptoms of EEE usually occur within the first seven to ten days of infection and begin with fever, chills, malaise (overall sick feeling), muscle and joint pains. Encephalitis symptoms are essentially the same as WNV (described above). According to the CDC, death may occur 2-10 days after the onset of symptoms. Those with more severe disease, who survive, may have prolonged neurologic ailments and mental disability and die within a few years.

    Add This Infographic to Your Website or Blog With This Code:

    The only good news here is that EEE infection is rare and doesn’t seem to be on the rise (at the time of this posting).


    There is no cure for these viral mosquito-borne illnesses. Supportive therapy may be required in a hospital setting. This usually means intravenous fluid, pain medications and bed rest. People with underlying chronic illnesses (diabetes, hypertension cancer etc.) are at higher risk of severe or fatal illness.



    What Can You Do to Avoid Infection?


    1) Avoid being outdoors for long periods of time at dusk if you are in a high risk area. But remember CV carrying mosquitos will bite during the day.


    2) Wear long sleeve shirts and pants during high risk times and when in high risk areas.


    3) Apply a recommended formulation of mosquito repellant.


    4) Identify potential havens for mosquito centers such as standing water, bird baths, old tires or blocked gutters and clear them out. Check on these areas weekly.


    5) Monitor mosquito activity in the state where you live. If there is a rising number of human infections beware of high risk circumstances mentioned above.


    6) Familiarize yourself and review the distinguishing features of encephalitis versus flu syndrome (discussed above)


    7) Notify your doctor if you have flu like illness and have been in a high risk situation over the past two weeks. If you have any of the signs of encephalitis call your doctor or local emergency department immediately.









    Map of West Nile Virus Activity (and links to others)


Published On: July 31, 2014