Warming helps mosquitoes, which spread crippling diseases

By Bill Barlow (The Press of Atlantic City) and Priyanka Runwal (Climate Central)

This story was produced through a collaboration between Climate Central and the Press of Atlantic City.

In 2019, a mosquito bite helped derail Timothy Ade’s life.

In August of that year, he began to complain of severe, debilitating headaches. Over-the-counter medicines did nothing to ease the pain, and a trip to the hospital resulted in a diagnosis of migraines.

His wife, Jennifer Ade, was not convinced. She pushed for more tests, she said, especially after Timothy developed a serious fever and had a seizure.

Eventually, she got an answer.

Timothy had eastern equine encephalitis, a viral illness caused by the bite of an infected mosquito. The disease is rare, extremely serious, and impacts humans and horses. According to the Centers for Disease Control and Prevention, about 30% of people with EEE die from it, and many more have ongoing neurological problems.

In a recent interview, Jennifer Ade said it was an extraordinary one-two punch that led to Timothy’s symptoms, with a bite from a tick that caused Rocky Mountain spotted fever, combined with the mosquito-borne encephalitis, which led to swelling in Timothy’s brain.

“We don’t know where he got the mosquito-borne illness,” Jennifer Ade said. “We don’t know where he got it or how long he had it.”

Mosquitoes are now emerging earlier in the spring and surviving longer into the fall, with close to an additional month of mosquito activity in the Atlantic City region. Data from the science and news group Climate Central found the mosquito season near Atlantic City is now 23 days longer on average than it was in 1979. A warming world may bring additional problems with mosquitoes.

A mosquito sample collected from Linwood has tested positive for West Nile virus, Atlantic County officials said Thursday.

Scientists and health experts are concerned that a changing climate may allow more mosquitoes of disease-causing species to move north, potentially bringing with them maladies formerly seen only in tropical climates.

Higher temperatures and favorable humidity in previously cold and inhospitable regions could mean mosquitoes grow faster and live longer. Warmer temperatures might also speed up virus reproduction in infected mosquitoes, allowing them to spread diseases more quickly.

A 2019 study estimates that within the next century, about a billion more people in the world may be exposed to mosquito-borne diseases. Scientists expect to see an uptick in EEE cases, which are often recorded in Eastern states and along the Gulf Coast.

According to the CDC, there were eight cases reported in New Jersey between 2003 and 2022. A map outlining reported cases shows 22 in Florida and 22 in Michigan during the same period.

Michael "Gus" Gustray, an Atlantic County biologist, checks results from a test. His job is to keep track of what mosquitoes are present in the county, from the harmless to the annoying to the few that are dangerous. | Credit: Bill Barlow, Press of Atlantic City

Keeping track

In a basement office, Patrick McGrath peers into a microscope, looking for the tiny telltale signs that will allow a positive identification of the mosquito remains on a glass slide.

McGrath is an identification specialist with the Atlantic County Office of Mosquito Control. Along with biologist Michael “Gus” Gustray, his job is to keep track of what mosquitoes are present in the county, from the harmless to the annoying to the few that are dangerous.

A mosquito bite has long been a metaphor for a harmless inconvenience. No one will miss the fraction of a milliliter of blood drawn in an average mosquito bite, and it might take more than a million bites to lose enough blood to die.

Preventing dengue fever has long meant teaching people to fear mosquitoes. Now scientists are promoting a potentially more effective way to control the disease — with the help of mosquitoes themselves.

But the tiny flying pests do kill, spreading a variety of diseases. Worldwide, mosquito-transmitted diseases account for more than 700,000 deaths a year, earning them the CDC’s title of the world’s deadliest animal.

Diseases like yellow fever and dengue infect millions of people around the globe, presenting serious problems in tropical areas.

In Atlantic and Cape May counties, the primary concerns are West Nile virus and EEE, each transmitted by infected mosquitoes and causing potentially deadly diseases in this region.

In September, Cape May County announced that testing found West Nile in two mosquito collections, including one close to the county zoo in Cape May Court House. At a third location, the county found EEE.

“Knowing that West Nile virus and eastern equine encephalitis are here in the county is a good reminder for people to protect themselves against mosquito bites,” said Kevin Thomas, the county health officer.

Mosquitoes can bite at any time of day and are particularly active during the early morning and early evening.

“To protect yourselves, you can wear long-sleeved shirts, long pants and use mosquito repellent when outdoors during these times,” Thomas said. “It is also important to eliminate standing water on your property that may serve as a habitat for mosquitoes and keep window screens in good repair.”

Doug Abdill, the superintendent of Atlantic County’s anti-mosquito efforts, said his county has seen indications of La Crosse encephalitis this year, another mosquito-borne viral illness.

Working on the front lines of mosquito control can be a prickly job for volunteers who give scores of the insects a chance to feed on their blood.

Encephalitis is an inflammation of the brain. There are many types, including those spread by mosquito bites. It can cause headaches, fatigue, stiff neck and other symptoms. In some cases, encephalitis may cause confusion, seizures and even death.

There have also been instances of Zika in the region, a mosquito-spread virus that can cause birth defects if spread from mother to fetus. And while there have been reports of other diseases more prevalent in tropical areas, officials say those were travel-related, meaning the bite occurred away from the region before a traveler returned and showed symptoms.

Patrick McGrath, an identification specialist with the Atlantic County Office of Mosquito Control, looks at characteristics to identify species of mosquitoes. There are 63 different mosquito species in New Jersey, and more than 40 of them live in Atlantic City. | Credit: Bill Barlow, Press of Atlantic City

Species spreading

McGrath and Gustray say there are 63 different species of mosquitos in New Jersey, and 40 of those have been found in Atlantic County. The two keep a lookout for new species, as changes in climatic conditions and habitat will affect where and how the different species can survive and thrive. In some instances, an increase in the range of a particular mosquito species may also increase the range of a disease.

As temperatures warm and rainfall patterns change, some species may find new areas. Those could include species of mosquitoes that serve as vectors for diseases, potentially bringing dangerous viruses.

“Things are working their way north,” said Matthew Diem, assistant superintendent of the Cape May County Mosquito Control Commission.

The Asian tiger mosquito, first detected in Texas in 1985, has continued to expand its range north due to milder winters. This invasive, striped mosquito feeds aggressively during the day and carries equine encephalitis, West Nile and other viruses. It can reproduce in a tiny amount of water — a puddle in an old tire or at the bottom of a potted plant can be enough.

“They got here, and they’re not going to leave,” Diem said.

A mosquito sample collected from Birch Grove Park in Northfield tested positive for West Nile virus, Atlantic County officials said Friday.

A sample of a mosquito as seen through a microscope at the Atlantic County Office of Mosquito Control. | Credit: Bill Barlow, Press of Atlantic City

Malaria worries

At one time, malaria was a leading cause of death in the United States. Fever from malaria killed about 10,000 Union Army recruits during the Civil War. By the 1950s, malaria was said to have been eliminated in the United States, even as it remained a serious concern worldwide. But like Zika and dengue, malaria infections continue to arise in New Jersey, at about 60 cases a year.

In most instances, they are determined to have been contracted by travelers outside the state, but that is not always certain. In September 1991, a 29-year-old woman arrived at her doctor’s office with chills, a fever, headache and a rash.

The Sicklerville, Camden County, resident was not identified by name in an article published soon after in the New England Journal of Medicine. She had not traveled, and reported frequently being bitten on her patio. Another patient, a 9-year-old from Monmouth County, also got sick from malaria that year.

The report found it was likely that both contracted the disease from mosquito bites in New Jersey, even though there had been no documented cases of transmission in the state for 30 years.

The authors recommended that surveillance of mosquito populations continue.

This year, in late June, the CDC warned of new instances of malaria transmission in the United States, in Florida and Texas. While there are hundreds of millions of cases of malaria each year, primarily in Africa, about 2,000 cases were diagnosed in the United States each year, mostly among travelers. Of those, maybe 300 experience severe symptoms, and five to 10 died each year.

The CDC called on doctors to consider malaria in diagnoses when someone has a fever, and to treat malaria as a medical emergency when it is found.

The Atlantic County Mosquito Control has scheduled multiple ground sprays for portions of Absecon, Pleasantville, Linwood and Somers Point.

Real world impacts

Jennifer Ade recalled how she and her husband enjoyed their backyard in Atlantic County on warm evenings. Jennifer was usually the one to decide to head inside as mosquitoes began to take their bloody toll.

“I always say I’m the sweetest because I’m the one getting bit,” she said.

The bites just didn’t seem to bother her husband as much. He worked with the Weymouth Township Public Works Department and enjoyed the outdoors in his free time.

Now 46, Timothy has difficulty walking and suffers from short-term memory loss. Jennifer said it would be impossible for him to perform the physical labor of his old job, and the couple rely on a home health aide.

Jennifer said she tries to remain positive, but her husband has found it extremely difficult to adjust to his new limitations.

“It has destroyed our lives,” she said.