Rare cases of mosquito- and tick-borne diseases, including Puasan and dengue fever, are appearing across the United States.

As summer draws to a close, cases of rare insect-borne diseases are emerging weekly across the country, including eastern equine encephalitis, dengue fever, West Nile virus – all spread by mosquitoes – and the tick-borne Powassan virus.

Alabama this week Two cases have been reported of eastern equine encephalitis, or EEE, including one death. He has a rare disease 30% fatality rateMany survivors suffer from permanent neurological problems. And in Connecticut, meanwhile, four residents He tested positive for the Powassan virusFirst case in the state this year.

The United States also recorded its first cases locally transmitted malaria In two decades this summer: seven in Florida and one each in Maryland and Texas.

Malaria cases aside, the one-off reports of these rare diseases are not surprising so far compared to years past, according to four experts interviewed. But they also noted that it is difficult to assess the situation until the final number of cases is counted later this year, and warming temperatures linked to climate change are likely to make ticks and mosquitoes a threat this fall and in the years to come.

A new set of Boasan cases

Maria Duke-Wasser, a vector-borne disease specialist and professor at Columbia University, said it’s unusual to see several Poasan cases at once in the same area, as happened recently in Connecticut.

She said the Connecticut cluster “looks like an anomaly with so many cases at once, but in general, all of these pathogens are increasing, including Powassan, although it’s very difficult to say exactly when you have such small numbers.” “

Prior to the Connecticut issues, A.J Residing in Rhode Island Died of the virus last week and Maine reported one death in May. The United States usually see about 30 cases annuallysaid Duke Wasser. As of Tuesday, the United States has recorded 16 cases this year. According to the Centers for Disease Control and Prevention. Powassan virus is commonly found in the Great Lakes region and the Northeast death rate about 10%. Its symptoms include fever, headache, vomiting and fatigue.

Duke Wasser’s lab studies ticks in and around New York City, and she said that this year her team detected higher levels of black-legged ticks, which can spread Powassan virus, as well as Lyme disease.

Health authorities monitor cases of EEE and dengue fever

EEE is among the rarest mosquito-borne diseases in the United States, and last year there was only one case, According to the Centers for Disease Control and Prevention, although the annual average has been hovering around eight for the past decade. The 2019 season was an exception, with 38 cases among them Nine deaths.

But the two Alabama cases are the only confirmed cases so far this year Michigan, Vermont And New York All of them reported in the past week that their mosquitoes tested positive for EEE.

The condition causes inflammation in the brain. Symptoms could be In some people, the disease is nonexistent or mild, but severe cases can lead to fever, headache, vomiting, seizures, and later coma.

John Rayner, associate professor of microbiology and immunology at the University of South Alabama, said that having one or two cases of EEE in one year is not unexpected for his state. But the season for ticks and mosquitoes extends into fall and winter, especially in the south, he said, adding that he was bitten by a tick while hiking in January.

“This is part of the concern about global warming,” he said. “As you can see temperatures stay high in the subtropics for longer periods of time, the transmission season is likewise extended.”

in June, The World Health Organization warned Rising temperatures due to global warming have also led to a global rise in dengue fever. In the United States, an outbreak of dengue fever this summer pushed two counties in Florida – Broward And Miami County – Daddy – To issue alerts on mosquito-borne diseases after the two locally acquired cases have been reported. In all, Florida recorded 147 cases, and New York It has been reported The next highest total is at 28.

About 1 in 4 infected people will develop dengue, with symptoms including fever, vomiting, rash, and muscle aches. According to the Centers for Disease Control and Prevention. Most people recover within a week, but about 1 in 20 people develop severe dengue, which can become life-threatening within a few hours after an individual’s fever begins to subside.

The United States has recorded 642 cases of dengue fever this year. According to the Centers for Disease Control and Prevention. This is much lower than last year’s total of more than 1,200 cases, but experts said the disease usually peaks in late summer, especially in August.

Thousands of West Nile cases arise each year

West Nile virus remains The main threat of mosquito-borne diseases in the United States As of August 22, 247 cases confirmed this year, with arizona and colorado having the most reports, According to the Centers for Disease Control and Prevention. last week,

Last year’s total cases exceeded 1,100, while 2021 saw the highest number of cases since 2012, with more than 3,000, according to a new report. CDC report Released Thursday.

Infections are usually recorded later in the season, experts said, and West Nile usually peaks in late summer and early fall, unlike most other mosquito-borne diseases.

just last week, Connecticut It reported its first human case this year, officials announced at the Montana And Texas He warned of the high number of cases.

Most people infected with West Nile virus do not become ill, but about 1 in 5 develop symptoms including fever, headache, body aches, joint pain, and vomiting. According to the Centers for Disease Control and Prevention. About 1 in 150 develops a serious or fatal illness that includes inflammation of the brain or spinal cord.

“It’s actually the neuroinvasive and neurodegenerative conditions in West Nile, which account for about 1% of all infections, and the real serious human conditions where you see hospitalization or long-term disability or possibly death,” said Graham McCain, assistant director of the Department of Public Health. “. and environmental health at Indiana University. “It usually takes longer over the course of a calendar year for us to catch on.”

He added that increasing monitoring of tick and mosquito populations is essential to combating the spread of these diseases.

“We kind of expect to see these diseases more and more as we continue to change the climate, as disease vectors arrive in new areas, and as funding and vector control decrease,” McCain said.

This article was originally published on NBCNews.com