The unnamed patient visited an urgent care clinic at North Central Florida in 2016, during the height of the international Zika virus outbreak. Doctors tested for Zika and could not identify what was causing the teenager to suffer a severe rash and fever until nearly a year and a half later. The mosquito-transmitted infection was first discovered in the United States in 1964 and is known to cause encephalitis, or inflammation of the brain, in mice and other animals. The virus can also cause a mild fever and rash in those affected. Researchers at the University of Florida reported on the findings in the journal Clinical infectious Diseases, adding that other humans could possibly already be infected. “Although the virus has never previously been found in humans, the infection may actually be fairly common in North Florida,” J Glenn Morris, director of the university's Emerging Pathogens Institute, said in a statement. The University of Florida says the Keystone virus “has been found in animal populations along coastal regions stretching from Texas to the Chesapeake Bay,” and is carried by the Aedes atlanticus mosquito. World news in pictures Show all 50 1 /50 World news in pictures World news in pictures 30 September 2020 Pope Francis prays with priests at the end of a limited public audience at the San Damaso courtyard in The Vatican AFP via Getty World news in pictures 29 September 2020 A girl's silhouette is seen from behind a fabric in a tent along a beach by Beit Lahia in the northern Gaza Strip AFP via Getty World news in pictures 28 September 2020 A Chinese woman takes a photo of herself in front of a flower display dedicated to frontline health care workers during the COVID-19 pandemic in Beijing, China. 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The fast moving Glass fire has burned over 1,000 acres and has destroyed homes Getty World news in pictures 26 September 2020 A villager along with a child offers prayers next to a carcass of a wild elephant that officials say was electrocuted in Rani Reserve Forest on the outskirts of Guwahati, India AFP via Getty World news in pictures 25 September 2020 The casket of late Supreme Court Justice Ruth Bader Ginsburg is seen in Statuary Hall in the US Capitol to lie in state in Washington, DC AFP via Getty World news in pictures 24 September 2020 An anti-government protester holds up an image of a pro-democracy commemorative plaque at a rally outside Thailand's parliament in Bangkok, as activists gathered to demand a new constitution AFP via Getty World news in pictures 23 September 2020 A whale stranded on a beach in Macquarie Harbour on the rugged west coast of Tasmania, as hundreds of pilot whales have died in a mass stranding in southern Australia despite efforts to save them, with rescuers racing to free a few dozen survivors The Mercury/AFP via Getty World news in pictures 22 September 2020 State civil employee candidates wearing face masks and shields take a test in Surabaya AFP via Getty World news in pictures 21 September 2020 A man sweeps at the Taj Mahal monument on the day of its reopening after being closed for more than six months due to the coronavirus pandemic AP World news in pictures 20 September 2020 A deer looks for food in a burnt area, caused by the Bobcat fire, in Pearblossom, California EPA World news in pictures 19 September 2020 Anti-government protesters hold their mobile phones aloft as they take part in a pro-democracy rally in Bangkok. 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Abe announced he will resign over health problems, in a bombshell development that kicks off a leadership contest in the world's third-largest economy AFP via Getty World news in pictures 27 August 2020 Residents take cover behind a tree trunk from rubber bullets fired by South African Police Service (SAPS) in Eldorado Park, near Johannesburg, during a protest by community members after a 16-year old boy was reported dead AFP via Getty World news in pictures 26 August 2020 People scatter rose petals on a statue of Mother Teresa marking her 110th birth anniversary in Ahmedabad AFP via Getty World news in pictures 25 August 2020 An aerial view shows beach-goers standing on salt formations in the Dead Sea near Ein Bokeq, Israel Reuters World news in pictures 24 August 2020 Health workers use a fingertip pulse oximeter and check the body temperature of a fisherwoman inside the Dharavi slum during a door-to-door Covid-19 coronavirus screening in Mumbai AFP via Getty World news in pictures 23 August 2020 People carry an idol of the Hindu god Ganesh, the deity of prosperity, to immerse it off the coast of the Arabian sea during the Ganesh Chaturthi festival in Mumbai, India Reuters World news in pictures 22 August 2020 Firefighters watch as flames from the LNU Lightning Complex fires approach a home in Napa County, California AP World news in pictures 21 August 2020 Members of the Israeli security forces arrest a Palestinian demonstrator during a rally to protest against Israel's plan to annex parts of the occupied West Bank AFP via Getty World news in pictures 20 August 2020 A man pushes his bicycle through a deserted road after prohibitory orders were imposed by district officials for a week to contain the spread of the Covid-19 in Kathmandu AFP via Getty World news in pictures 19 August 2020 A car burns while parked at a residence in Vacaville, California. Dozens of fires are burning out of control throughout Northern California as fire resources are spread thin AFP via Getty World news in pictures 18 August 2020 Students use their mobile phones as flashlights at an anti-government rally at Mahidol University in Nakhon Pathom. Thailand has seen near-daily protests in recent weeks by students demanding the resignation of Prime Minister Prayut Chan-O-Cha AFP via Getty World news in pictures 17 August 2020 Members of the Kayapo tribe block the BR163 highway during a protest outside Novo Progresso in Para state, Brazil.<doc-sep>There's a new mosquito-borne virus to be wary of — or at least new to those of us who don't study such viruses. A teenager in Florida is the first person known to be infected with a virus called Keystone virus, which is spread by mosquitoes. The teen visited an urgent care clinic in North Central Florida in August 2016, after he developed a fever and rash, according to a new report of his case, published June 9 in the journal Clinical Infectious Diseases. Doctors initially thought the teen might have an infection caused by the Zika virus — after all, his visit occurred in the midst of the Zika epidemic in Florida — but tests for that virus came back negative. But unexpectedly, researchers from the University of Florida (UF) found the Keystone virus in samples from the patient. The Keystone virus was first discovered in 1964 in the Tampa Bay area, and has been previously found in animals, according to a statement from the University of Florida. Doctors had suspected the virus might infect people, but they hadn't found the virus in humans, until now. [5 Weird Effects of Bug Bites] The researchers say there could be other, undiagnosed cases of this virus. "Although the virus has never previously been found in humans, the infection may actually be fairly common in North Florida," Dr. J. Glenn Morris, director of the UF Emerging Pathogens Institute, said in the statement. "It's one of these instances where if you don't know to look for something, you don't find it." Although the teen's symptoms were mild, it's possible that the Keystone virus may cause more severe symptoms in people, including brain infections. Two relatives of the Keystone virus, the Jamestown Canyon virus and La Crosse encephalitis virus, can cause inflammation of the brain, called encephalitis. The researchers say the discovery of the Keystone virus in a person highlights the need for more research into the prevalence of mosquito-borne diseases in the U.S. "All sorts of viruses are being transmitted by mosquitoes, yet we don't fully understand the rate of disease transmission," Morris said. Originally published on Live Science.<doc-sep>
A teenager in Florida has become the first person known to be infected with mosquito-borne Keystone virus but is unlikely to be the only case, according to researchers. Scientists from the University of Florida documented the Keystone virus, which had been confirmed in an unnamed teenager after he experienced a rash and a fever, in research published in the journal Clinical Infectious Diseases. The Keystone virus was first identified in the U.S. in 1964 and named after the area in Tampa Bay where it was found. It was known to affect animals on the coast from Texas to Chesapeake Bay. "By finding the virus in a person, this tells us that the virus can infect humans, and that perhaps the former studies that indicated up to 20 percent of Florida residents of the Tampa area have been exposed to this virus (and not another closely-related one) are correct," John Lednicky, a research professor in the University of Florida's College of Public Health and Health Professions and lead author of the study, told Newsweek. "It is likely that those who live in Florida get exposed sometime when they are young, and now have immunity to the virus," said Lednicky. Symptoms in humans include a rash and a mild fever. Researchers stressed the importance of protecting oneself from mosquito bites by using repellent at all times in areas where mosquitoes are common. In August 2016, a teenage boy presented at a clinic in Florida with these symptoms during the Zika epidemic, prompting clinicians to collect viral samples from him. The teenager did not show signs of encephalitis, a condition in which the brain becomes inflamed. However, when the Keystone virus was tested in mouse brain cells it developed in a way which suggests the virus has the potential to infect this tissue, and could pose a risk for infections, according to researchers. Lednicky explained the virus is part of a group known as the California serogroup of viruses. The most common are Jamestown Canyon and La Crosse encephalitis virus. "These viruses are known to cause encephalitis in several species, including humans," he said. Although the virus had never been found in humans until now, experts have long believed it could or had infected humans. In 1972, an article in the American Journal of Tropical Medicine and Hygiene showed around a fifth of the population of Tampa Bay carried Keystone virus antibodies. The new case is part of a wider pattern of a rise in vector-borne diseases in the U.S. Since the early 2000s, cases have doubled, according to a recent study by the Centers for Disease Control and Prevention. Dr. J. Glenn Morris, director of the University of Florida's Emerging Pathogens Institute and co-author of the report, stressed in a statement: "Additional research into the spread of vector-borne diseases will help us shine a light on the pathogens that are of greatest concern to both human and animal health.'' This piece has been updated with comment from John Lednicky.