Posts Tagged ‘disease’

by Jennifer Kay

Mosquitoes are a year-round downside to living in subtropical Miami, but millions of bacteria-infected mosquitoes flying in a suburban neighborhood are being hailed as an innovation that may kill off more bugs that spread Zika and other viruses.

Miami-Dade County Mosquito Control and Habitat Management Division is releasing non-biting male mosquitoes infected with teh naturally occurring Wolbachia bacteria to mate with wild female mosquitoes.

The bacteria are not harmful to humans but will prevent any offspring produced when the lab-bred mosquitoes mate with wild female mosquitoes from surviving to adulthood. This drives down the population of Aedes aegypti mosquitoes that thrive in suburban and urban environments and can spread Zika, dengue fever and chikungunya.

During a six-month field trial approved by the U.S. Environmental Protection Agency, over half a billion of the mosquitoes bred by Kentucky-based MosquitoMate will be released in a suburban neighborhood split by long, narrow canals near the University of Miami, said South Miami Mayor Philip Stoddard.

Miami-Dade County is testing MosquitoMate’s insects as a potential mosquito-control method about 10 miles southwest of Miami’s hip Wynwood neighborhood, where health officials confirmed the first local Zika infections spread by mosquitoes on the U.S. mainland in July 2016.

Stoddard, a zoology professor at Florida International University, said he volunteered his city for the trial, wanting to keep the outdoor cafes in his city from becoming another ground zero for a mosquito-borne virus outbreak.

“All those diseases are still a concern,” he said. “They’re still in the Caribbean and could move to the mainland to cause problems.”

By the end of 2016, Florida health officials had confirmed 1,456 Zika infections in the state, including 285 cases spread by mosquitoes in Miami-Dade County. Just two local Zika infections were reported in Florida last year, including one Miami-Dade case.

If MosquitoMate’s bugs perform well in South Miami, Wolbachia could be added to regular mosquito control operations as a long-term preventative strategy, said Bill Petrie, Miami-Dade County’s mosquito control chief.

“It’s not a silver bullet,” he said. “You’d want to integrate it into your existing methods.”

It would not replace naled, the pesticide sprayed from airplanes during the 2016 outbreak, angering Miami residents concerned the chemicals were more dangerous than Zika. Health officials credited naled among other aggressive response efforts with stopping the outbreak.

MosquitoMate’s technology appears low-tech in the field. Infected mosquitoes are shipped weekly in cardboard tubes — similar to the ones used in paper towel rolls — from Lexington, Ky.

Each tube contains a thousand mosquitoes. In a demonstration Thursday in a city park, a cloud of mosquitoes burst from one end when a black netting cover was removed; a firm shake sent any stragglers flying out.

The trial will study how far the mosquitoes fly, how long they live in the area, and how many Aedes aegypti eggs hatch compared to untreated areas, MosquitoMate founder Stephen Dobson said.

Results from a similar trial near Key West last year are awaiting publication, he said.

Last year, the EPA approved permits for MosquitoMate to sell a related mosquito species, known as the “Asian tiger mosquito,” infected with Wolbachia as a pest control service in 20 states and Washington, D.C. Those mosquitoes also can carry viruses, but experts consider them less of a threat for triggering outbreaks than Aedes aegypti.

http://www.orlandosentinel.com/news/os-modified-mosquitoes-20180208-story.html

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By SAM ROBERTS

Julius Youngner, an inventive virologist whose nearly fatal childhood illness destined him to become a medical researcher and a core member of the team that developed the Salk polio vaccine in 1955, died on April 27 at his home in Pittsburgh. He was 96.

His death was confirmed by his son, Dr. Stuart Youngner.

Dr. Youngner was the last surviving member of the original three-man research team assembled by Dr. Jonas Salk at the University of Pittsburgh to address the polio scourge, which peaked in the United States in the early 1950s when more than 50,000 children were struck by it in one year. Three other assistants later joined the group.

Dr. Salk credited his six aides with major roles in developing the polio vaccine, a landmark advance in modern medicine, which he announced on April 12, 1955.

The announcement — that the vaccine had proved up to 90 percent effective in tests on 440,000 youngsters in 44 states — was greeted with ringing churchbells and openings of public swimming pools, which had been drained for fear of contagion. Within six years, annual cases of the paralyzing disease had declined from 14,000 to fewer than 1,000.

By 1979, polio had been virtually eliminated in developed nations.

“I think it’s absolutely fair to say that had it not been for Dr. Youngner, the polio vaccine would not have come into existence,” Dr. Salk’s son, Peter L. Salk, president of the Jonas Salk Legacy Foundation and a visiting professor at the University of Pittsburgh Graduate School of Public Health, said in an email.

While Dr. Youngner, who was 34 at the time, remained at the university and made further advances in virology, he and other members of the team remained embittered that Dr. Salk had not singled them out for credit in his announcement speech.

The printed version was prefaced with the phrase “From the Staff of the Virus Research Laboratory by Jonas E. Salk, M.D.,” and a United Press account quoted him as crediting his original three assistants, who had joined him as early as 1949 — Dr. Youngner, Army Maj. Byron L. Bennett and Dr. L. James Lewis — as well as three others.

“The really important thing to recognize is that the development of the polio vaccine at the University of Pittsburgh was a team effort,” Dr. Peter Salk wrote.

He added, “There is no question that my father recognized the importance of the team, and if there were circumstances in which that wasn’t adequately expressed, I would feel that it needs to be expressed now and very clearly so.”

In 1993, Dr. Youngner crossed paths with Dr. Salk for the first time since Dr. Salk left for California in 1961. According to “Polio: An American Story” (2005), by David M. Oshinsky, Dr. Youngner raised the 1955 announcement speech in confronting Dr. Salk.

“Do you remember whom you mentioned and whom you left out?” the book quoted him as saying to Dr. Salk. “Do you realize how devastated we were at that moment and ever afterward when you persisted in making your co-workers invisible?”

Asked later, though, whether he regretted having worked for Dr. Salk, Dr. Youngner replied: “Absolutely not. You can’t imagine what a thrill that gave me. My only regret is that he disappointed me.”

Dr. Youngner’s contribution to the team was threefold.

He developed a method called trypsinization, using monkey kidney cells to generate sufficient quantities of the virus for experiments and production of the vaccine. He also found a way to deactivate the virus without disrupting its ability to produce antibodies. And he created a color test to measure polio antibodies in the blood to determine whether the vaccine was working.

He later contributed research to understanding interferon as an antiviral agent in the treatment of cancer and hepatitis; to the development (with Dr. Samuel Salvin) of gamma interferon, which is used against certain infections; and to advances that resulted in vaccines for Type A influenza and (with Dr. Patricia Dowling) equine influenza.

“As a direct result of his efforts, there are countless numbers of people living longer and healthier lives,” Dr. Arthur S. Levine, the University of Pittsburgh’s senior vice chancellor for the health sciences and dean of its medical school, said in a statement.

Julius Stuart Youngner was born on Oct. 24, 1920, in Manhattan and raised in the Bronx, where he survived lobar pneumonia, a severe infection of the lungs. His father, Sidney Donheiser, was a businessman. His mother was Bertha Youngner. He took her surname when his parents divorced.

After graduating from Evander Childs High School in the Bronx at 15, he earned a bachelor’s degree in English with a minor in biology from New York University in 1939 and a master’s and doctorate of science in microbiology from the University of Michigan.

Drafted into the Army in World War II, he worked on the Manhattan Project at Oak Ridge, Tenn., and at the University of Rochester, testing the toxicity of uranium salts. He said he learned of the project’s goal of building an atomic bomb only when it was dropped on Japan.

He was working at the National Cancer Institute, part of the National Institutes of Health, when the University of Pittsburgh hired him as an assistant professor in 1949 to assist Dr. Salk. He was a professor of microbiology and medical genetics at the university School of Medicine and chairman of the department of microbiology (biochemistry and microbiology were added later) from 1966 until his retirement in 1989.

His first wife, the former Tula Liakakis, died in 1963. Besides their son, Stuart, a psychiatry and bioethics professor at Case Western Reserve University in Cleveland, Dr. Youngner is survived by his wife, the former Rina Balter; a daughter, Lisa, an artist, also from his first marriage; three grandchildren; and a half brother, Alan Donheiser.

Dr. Youngner’s infectious curiosity, as a colleague characterized it, generated hundreds of scholarly papers and more than 15 patents. He was president of the American Society for Virology from 1986 to 1987.

When he was 7, Dr. Youngner nearly died from the pneumonia he had contracted when bacteria ate through his chest and infected a rib. An effective vaccine for pneumonia and antibiotics would not be invented for nearly two decades.

“So they strapped my legs to a table, and two nuns held my arms and another held my head and they prayed while they operated on me,” he recalled in an oral history interview in the early 1990s with the National Council of Jewish Women. “To this day I can remember the feeling of the saw on that rib.

“Later in life, when I had to have some minor surgery,” he said, “I put it off for years because I was so affected by this episode.”

https://mobile.nytimes.com/2017/05/04/science/julius-youngner-dead-salk-polio-vaccine-researcher.html?_r=0&referer=https://www.google.com/


The birds seem to buffer humans from West Nile virus, according to a new study, especially in cities with more patches of old-growth forest.

by Rusell McLendon

The northern cardinal is one of North America’s most familiar songbirds. From the scarlet feathers and pointed crest of males to the rich, rhythmic songs of both sexes, it’s an unmistakable icon of countless American forests, parks and backyards.

And as a new study demonstrates, northern cardinals are much more than just scenery and a soundtrack. As part of eastern North America’s native biodiversity, they can also play a key role in keeping ecosystems — including humans — healthy.

That’s according to new research from Atlanta, where a team of scientists wanted to figure out why more people don’t get sick with West Nile virus (WNV). The mosquito-borne virus is zoonotic, meaning it can be spread between humans and other animals by a “bridge vector,” a role played by Culex mosquitoes for WNV.

Since WNV was introduced to the U.S. in 1999, it has become the country’s most common zoonotic disease carried by mosquitoes, causing more than 780,000 infections and 1,700 deaths. But for some reason, the virus sickens people in some areas more than others. It’s abundant in both Georgia and Illinois, for example, showing up in nearly 30 percent of birds tested in Atlanta, compared with 18.5 percent in Chicago. Yet only 330 human cases have been reported throughout Georgia since 2001, while Illinois has seen 2,088 human cases since 2002.

“When West Nile virus first arrived in the United States, we expected more transmission to humans in the South, because the South has a longer transmission season and the Culex mosquitos are common,” says senior author Uriel Kitron, chair of environmental sciences at Emory University, in a statement. “But even though evidence shows high rates of the virus circulating in local bird populations, there is little West Nile virus in humans in Atlanta and the Southeast in general.”

The reason for that difference has remained a mystery for years, prompting a three-year study by a team of scientists from Emory, the University of Georgia, the Georgia Department of Transportation and Texas A & M University. They collected mosquitoes and birds from various sites across Atlanta, tested them for WNV, and analyzed DNA from their blood meals to learn which birds they’d been biting.

“We found that the mosquitoes feed on American robins a lot from May to mid-July,” says lead author Rebecca Levine, a former Emory Ph.D. student now working at the U.S. Centers for Disease Control and Prevention (CDC). “But for some unknown reason, in mid-July, during the critical time when the West Nile virus infection rate in mosquitos starts going up, they switch to feeding primarily on cardinals.”

Previous research has shown American robins act as “super spreaders” of WNV in some cities like Chicago, Levine adds. Something about their blood creates a favorable environment for WNV, so the virus amplifies wildly once a robin is infected, meaning the birds can more efficiently pass it to new mosquitoes when bitten.

But cardinals have the opposite effect. Their blood is like an abyss for WNV, leading the researchers to describe the birds as “super suppressors” of the virus.

“You can think of the cardinals like a ‘sink,’ and West Nile virus like water draining out of that sink,” Levine says. “The cardinals are absorbing the transmission of the virus and not usually passing it on.” Cardinals seem to be the top suppressors of WNV, the study found, but similar effects are seen in birds from the mimid family — namely mockingbirds, brown thrashers and gray catbirds, all of which are common in Atlanta.

http://www.mnn.com/health/healthy-spaces/blogs/why-cardinals-can-be-good-human-health