Mosquito-Borne Diseases and the Elderly

As the summer season rolls around once again, officials in southern New England are beginning to test for Eastern Equine Encephalitis (EEE) and West Nile Virus (WNV). Thus far, testing has turned up no mosquitos carrying EEE or WNV in Rhode Island, Massachusetts, or Connecticut. But it is early in the season and officials report that most cases occur from late July through October.

"Mosquitos, small as they are, are responsible for between 800,000 and a million deaths annually worldwide, according to the World Health Organization," said certified elder law Attorney RJ Connelly III. "Mosquitos cause more death and suffering than any other organism on earth."

"Here in New England, the most recent outbreak of EEE occurred in 2019, according to the CDC," stated Attorney Connelly. "There were thirty-two known cases that killed twelve of those infected. This disease has a 30 percent fatality rate, similar to Ebola or smallpox. Of those who do survive, nearly half will have long-term neurological complications."

"So, we wanted to provide some information on the diseases mosquitoes are responsible for including those that affect us right here in southern New England," said Attorney Connelly. "We also wanted to provide links to the CDC site that continually monitors mosquito activity in your area so you can make a safe decision about travel and vacationing. Save this link and use it during mosquito season."

Diseases Spread by Mosquitoes

Eastern Equine Encephalitis

Massachusetts is ground zero for this infection. EEE was first found in horses in Massachusetts in 1831 and in 1938, the first confirmed human cases were found here in New England. Today, EEE is present in North, Central, and South America where it is known as “sleeping sickness”.

Massachusetts is ground zero for EEE

The mosquito that carries EEE prefers to bite animals but will also dine on humans. However other mosquitoes, who do feed on both humans and animals, can carry the disease between the species. These mosquitoes include the Aedes, whom we are most familiar with.

The risk of contracting the EEE virus is highest during the summer months and those who live and work near wetland and swamp areas are at higher risk of infection. And as we stated earlier, EEE is only spread to humans via mosquito bites and not through infected animals.

"...the elderly (ages fifty and over) and the young (ages fifteen and under) are at greatest risk of developing encephalitis from EEE."

Of those who contract the EEE virus, the elderly (ages fifty and older) and the young (ages fifteen and younger) are at the greatest risk of developing encephalitis. EEE can lead to a fever, headaches, vomiting, diarrhea, irritability, drowsiness, lack of appetite, seizures, falling into a coma, and potentially death. So dangerous is this disease that one in three people who contract it do not survive. According to the CDC, death can be rapid, just 2 to 10 days after symptoms appear. Of those who do survive, nearly half are left with lingering mental and physical impairments, such as difficulty thinking, personality disorders, seizures, paralysis, and several types of nervous system dysfunction.

West Nile Virus

This year marks the twenty-second anniversary of the detection of the West Nile virus in this country. Last year, there were over 2690 cases of West Nile virus in the United States, a slight uptick from the case counts reported in the previous five summers. The last time the US saw more cases was in 2012 when there were 5674 cases reported. According to the CDC, the West Nile virus is now the leading cause of mosquito-borne disease in the continental United States. As of June 28, 2022, a total of 10 cases of West Nile virus disease in people have been reported to CDC. Of these, 7 (70%) were classified as neuroinvasive diseases (such as meningitis or encephalitis) and 3 (30%) were classified as non-neuroinvasive diseases.

Twenty two years since West Nile appeared here

This virus was first isolated in Africa in 1937 and quickly spread throughout the region. Then in 1999, a strain of the virus that was active in Israel and Tunisia was imported into New York and resulted in a huge outbreak that spread throughout the continental United States. Today, the virus has firmly established itself in this country.

The virus is transmitted by the Culex mosquito, which acquires the virus by feeding on infected birds. The strain that is active in the United States is extremely deadly for crows, so the sight of dead birds may indicate the presence of this virus in the area.

"...people older than fifty and especially those over sixty-five have the highest risk of developing encephalitis from the West Nile Virus."

About 80 percent of those who are bitten by infected mosquitoes do not develop any symptoms, but in the 20 percent who do, they develop fevers, aches, and nausea -- and about 1 in 150 of this group will develop encephalitis, a much more serious disease, which could result in death.

Unfortunately, people older than fifty and especially those over sixty-five, have the highest risk of developing encephalitis. There is no vaccine for West Nile and treatment consists of addressing the symptoms such as fever and dehydration. In severe cases, hospitalization may become necessary.

We Live in a Smaller World

"We discussed the two viruses we are most concerned with here in Southern New England, but the reality is that today’s seniors are much more mobile and are on the move around our country and the world, putting them at risk for other infections carried by these insects," Attorney Connelly points out. "Still others, who may have immigrated to this country, return home to visit family members and encounter various diseases and viruses not seen here. This includes those traveling to the Caribbean, Asia, and parts of Africa."

People are traveling again after the pandemic

“It’s great that our seniors are traveling and visiting other countries," said Attorney Connelly. “But with this travel come concerns that seniors must be aware of. This includes the infections carried by mosquitoes in parts of the world that don’t have the same standards of hygiene as we do here or have the immunity that those living there may have. Traveling does come with risks. And knowing these risks and the precautions to take may keep them safe.”

Among these risks include some of the major infections carried by mosquitoes not commonly seen in Southern New England like Zika, Chikungunya, Yellow Fever, Rift Valley Fever, Malaria, and Dengue. Let's briefly look at them.


Just a few years ago, the Zika virus made headlines about its rapid spread across the globe. Although the Zika hysteria has subsided, it doesn’t mean it has disappeared. in fact, one could argue that Zika may pose more of a risk to people than EEE and WNV because of how it can be transmitted.

Babies born with microcephaly due to Zika

Those who contract this virus usually experience no symptoms or only a mild disease that may involve fever, rash, and joint pain in most people who become infected. However, the disease can cause severe neurological defects in the developing fetuses of pregnant women who are infected with the Zika virus. A substantial number of the babies of these women are born with microcephaly, a rare disorder in which a baby’s head is much smaller than normal. This defect can lead to developmental problems ranging from mild to severe and is sometimes fatal.

Zika was an obscure virus that was not associated with any serious disease until it emerged explosively in Brazil in 2015 and spread rapidly throughout Latin America. With the Olympic games being held there in 2016, visitors and athletes were cautioned about the bites of the mosquitoes. Because the Zika virus had not been found in the Americas previously, there was no immunity to the virus in the population meaning that almost everyone was susceptible.

"...the one thing that makes Zika much different than EEE and WNV is that it can be spread from human to human through sexual intercourse..."

But the one thing that makes Zika much different than EEE and WNV is that it can be spread from human to human through sexual intercourse, a sexually transmitted infection of sorts. The type of sex that can spread Zika includes vaginal, anal, and oral sex and even the sharing of sex toys. Zika can even be passed through sex even in committed relationships. The time frames that men and women can pass Zika through sex are different because the Zika virus can stay in semen longer than in other body fluids. Zika can also be spread through blood transfusions.

In a recent study, Zika has been shown to live outside the body, on non-biological surfaces, for up to eight hours. And according to researchers, in environments where blood or blood spatters are present, it can survive much longer.

Although Zika has been primarily discussed around the dangers for pregnant women, there are some specific risks for senior citizens which include the following:

Guillain-Barre Syndrome is associated with Zika
  • Guillain-Barré syndrome (GBS) is associated both with older age and the Zika virus. GBS is a rare disorder that causes a person’s immune system—how the body fights off disease—to damage its own nerve cells. It can cause muscle weakness and paralysis, sometimes affecting the muscles that control a person’s breathing. In severe cases, GBS can result in death. The risk for GBS increases with age, and people aged fifty and older are most affected.

  • And remember, age does not protect you from sexually transmitted diseases. Zika can be passed from a person who has the virus to his or her sex partners. No matter how old you are, you should practice safe sex and use condoms if you or your partner show symptoms or have recently traveled to an area where Zika is found.

As with the previous viruses we discussed, there is no vaccine and treatments consist of addressing the symptoms.

Current Zika information for 2022


Although rarely fatal, chikungunya is a virus that causes debilitating joint pain accompanied by fever and rash. First found in the tropics of Africa, it rapidly spread east into Europe and then into the America’s. By 2017, there were more than 1.7 million infections in North and South America.

Chikungunya infection as it manifests on the skin

In countries where chikungunya is most active, health experts say there are more chances of elderly patients succumbing to the disease due to their low immunity levels, combined with chronic health problems like heart or kidney ailments.

"The problem can be severe among those who already have kidney problems, chest infections, and heart diseases. The virus can stop the functioning of the organs. This is most common among elderly patients with low immunity power. The whole story is about immunity," said Dr. Sumit Ray, who heads the critical care unit at Sir Ganga Ram Hospital in India, where this virus has a stronghold.

There is no vaccine for chikungunya and the symptoms are treated. However, during the first week of the virus, a mosquito can spread it from one infected person to another.

Yellow Fever

Yellow fever, you might ask? Why is this being discussed in the United States? Well, the United States has quite a history of Yellow Fever outbreaks.

The Yellow Fever outbreak in Philadelphia

One of the first Yellow Fever outbreaks here occurred during the late 1600s followed by another during the summer of 1793 when refugees from a yellow fever epidemic fled the Caribbean and ended up in Philadelphia. Within weeks, the city was loaded with citizens reporting symptoms. By early fall, over one hundred people were dying daily. By the time it was over, over five thousand people died in Philadelphia alone.

During the Civil War, more soldiers died from disease than from actual battle-related injuries. Yellow Fever, called "Yellow Jack" by the soldiers, could wipe out a platoon in a matter of weeks. But with better sanitation, knowledge of mosquito control methods, and education on protection against the bites of this insect, diseases like Yellow Fever have all but disappeared from the United States. But it is still widespread in areas where Americans travel and visit relatives.

This does not mean that we will never experience another Yellow Fever outbreak here. In April of 2018, the World Health Organization identified Miami, Florida as one of the global cities that is susceptible to the spread of this disease because travel here does not require an immunization. Infected travelers arriving in South Florida could be bitten by mosquitoes here, which could then spread the disease through bites to other people.

"Yellow fever vaccine should be given cautiously to people older than sixty years and it should not be given at all to people with certain immune-suppressing conditions [because it contains the live virus]."

In mild cases, yellow fever causes fever, headache, nausea, and vomiting. But yellow fever can become more serious, causing heart, liver, and kidney problems along with bleeding (hemorrhaging). Up to 50 percent of people with the more severe form of yellow fever die of the disease.

Thankfully, there is a vaccine for Yellow Fever. But it comes with caution – it does contain the live virus. Yellow fever vaccine should be given cautiously to people older than 60 years, and it should not be given at all to people with certain immune-suppressing conditions. Seniors should discuss their detailed travel plans with their doctors and, if necessary, alternatives to vaccination.

Once yellow fever is contracted, the symptoms are treated and not the disease. Because Yellow Fever can cause bleeding, certain medications that interfere with clotting need to be avoided.

Traveling to these areas? The CDC recommends the Yellow Fever vaccine but it can be harmful to some seniors.


Dengue has emerged as a worldwide problem only since the 1950s. Although dengue rarely occurs in the continental United States, it is endemic in Puerto Rico and in many popular tourist destinations in Latin America, Southeast Asia, and the Pacific islands.

Philippine dengue outbreak in 2019

The principal symptoms of dengue fever are high fever, severe headache, severe pain behind the eyes, joint pain, muscle and bone pain, rash, and mild bleeding (e.g., nose or gums bleed, easy bruising). Generally, younger children and those with their first dengue infection have a milder illness than older children and adults.

Dengue is a neglected tropical disease that is increasingly affecting elderly patients. However, with the aging population, there has been an increase in dengue incidence rates in older adults. In Taiwan, older adults have the highest reported dengue incidence rate and risk of fatality. Likewise in Singapore elderly patients accounted disproportionately for most dengue deaths highlighting the urgent need for enhanced understanding of dengue in the elderly to improve clinical management and outcome.

Once dengue is contracted, it is only the symptoms that can be treated. The Dengue fever risk is very close to the continental United States and very active in vacation spots frequented by seniors, including Caribbean, Mexico, and South American "hot spots".

Rift Valley Fever

Rift Valley fever (RVF) is an acute, fever-causing viral disease most observed in domesticated animals (such as cattle, buffalo, sheep, goats, and camels), with the ability to infect and cause illness in humans. It was first reported in livestock by veterinary officers in Kenya’s Rift Valley in the early 1910s. RVF is found in regions of eastern and southern Africa where sheep and cattle are raised, but the virus exists in most of sub-Saharan Africa, including West Africa and Madagascar.

Government officials try to educate citizens

In September 2000, an RVF outbreak was reported in Saudi Arabia and subsequently, Yemen. This outbreak represents the first cases of Rift Valley fever identified outside Africa. People are infected with the RVF virus (RVFV) through contact with blood, body fluids, or tissues of RVFV-infected animals, mainly livestock.

Less commonly, people can be infected with RVFV from bites of infected mosquitoes and, rarely, from other biting insects that have the virus on their mouthparts. Spread from person to person has not been documented. RVF virus has an incubation period of 2-6 days following infection and can cause several different disease syndromes. Most commonly, people with RVF have either no symptoms or a mild illness associated with fever and liver abnormalities.

Patients who become ill usually experienced fever, generalized weakness, back pain, and dizziness at the onset of the illness. Typically, patients recover within two days to one week after the onset of illness. However, a small percentage (8-10%) of people infected with RVFV develop much more severe symptoms, especially among the elderly.


Malaria is a mosquito-borne disease caused by a parasite. People with malaria often experience fever, chills, and flu-like illness. Left untreated, they may develop severe complications and die. According to the latest World Malaria Report, released in 2021, there were 241 million malaria cases and 627,000 malaria deaths worldwide in 2020. This represented about fourteen million more cases in 2020 compared to 2019, and 69,000 more deaths. Approximately two-thirds of these additional deaths (47,000) were linked to disruptions in the provision of malaria prevention, diagnosis, and treatment during the pandemic.

About 1,700 cases of malaria are diagnosed in the United States each year. The vast majority of cases in the United States are in travelers and immigrants returning from countries where malaria transmission occurs, many from sub-Saharan Africa and South Asia.

"Researchers found...that the risk of dying from the disease [malaria] for tourists increases steadily with age. Those over sixty-five are ten times more likely to die from the disease than those aged 18-25..."

Researchers from the London School of Hygiene and Tropical Medicine and the University of Oxford found that the risk of dying from the disease for tourists who have visited a malaria-infected country increases steadily with age. Those over the age of sixty-five are almost ten times more likely to die from the disease than those who are aged 18-35, they revealed in a study published online by the British Medical Journal

There are currently several vaccines that can provide some protection and recent research is suggesting combining them for better outcomes. If malaria is contracted, there are multiple medications used to treat it.

It's About Protection

If you are in your backyard around dusk or relaxing on a beach in the Virgin Islands, protecting yourself is the best way to avoid getting sick. The CDC says that modern mosquito control methods are great at keeping these insects at bay, but all bets are off outside this country.

It's all about protection

According to the CDC, there are some things that you can do to limit your risks:

  • Reduce the number of bites you get by using EPA-approved insect repellent products. EPA-approved bug spray includes those with the following active ingredients: DEET (20-30% strength); picaridin, IR3535; and oil of lemon eucalyptus or paramenthane.

  • Mosquitoes are most active from dusk to dawn. Avoid being outside during these hours or wear repellent and protective clothing during these hours.

  • Reduce the number of mosquitoes by emptying standing water, changing bird bath water, and maintaining clean gutters.

  • Help seniors by repairing window screens or screen doors.

  • If you plan to travel, check with your doctor about vaccines or boosters that may be helpful.

  • Know where you are going and know what diseases or viruses are most active there.

  • Those with a chronic health condition should factor this in when planning travel destinations.

“When we do blogs like this, we are not crying wolf or trying to scare seniors as contracting these diseases are relatively uncommon," states Attorney Connelly. “But what we are doing is acknowledging that we live in a different time where travel and outdoor activities are now the norm for people of all ages. We look to educate and hopefully help our seniors make better decisions around personal safety given the increased susceptibility that occurs with age and the environmental dangers that are present."