Mosquitos to be infected with bacteria in fight against Zika virus

Mosquitoes in two large areas of Brazil and Colombia are to be infected with bacteria that deprive them of the ability to transmit viruses, in an attempt to check the spread of Zika, which has been held responsible for brain damage in thousands of babies.

Funding the ambitious plan are two philanthropic foundations – the Wellcome Trust and the Bill and Melinda Gates Foundation – together with the Brazilian, UK and US governments. The scheme will cost $ 18m (£14.7m) and is supported by the World Health Organisation (WHO).

Wolbachia bacteria are carried by around 60% of the world’s insect species, but not by the Aedes aegypti mosquito, which transmits Zika, dengue, yellow fever and chikungunya viruses to humans.

Researchers at Australia’s Monash University have been working for the past decade to infect mosquitoes with Wolbachia in an effort specifically to eliminate dengue, but the Zika crisis in Latin America has focused attention and now major funding on their work.

Following successful trials in Australia, Indonesia and Vietnam, including small-scale projects last year in Latin America, Wolbachia-infected mosquitoes will be released across two large urban areas – in Rio de Janeiro in Brazil and in Antioquia in Colombia, starting next year. The infected mosquitoes breed with local mosquitoes and pass the Wolbachia bacteria on to their offspring, so the project is self-sustaining. In those areas where trials have been done so far, transmission of the viruses has stopped.

“Wolbachia could be a revolutionary form of protection against mosquito-borne disease. It’s affordable, sustainable, and appears to provide protection against Zika, dengue, and a host of other viruses. We’re eager to study its impact and how it can help countries,” said Dr Trevor Mundel, president of the global health division of the Bill and Melinda Gates Foundation.

The World Health Organisation earlier this year called for large-scale pilot studies of the Wolbachia mosquito-control method and the Pan-American Health Organisation offered technical support in countries affected by Zika.

The idea emerged from the Grand Challenges programme backed by the Gates Foundation, which each year calls for scientists to bid for funds with creative new ideas to solve some of the world’s most pressing health problems. Prof Scott O’Neill’s team from Monash University proposed Wolbachia infection of mosquitoes to stop dengue transmission in 2005.

Jeremy Farrar, director of the Wellcome Trust, told the Guardian it was vital for the scientists to ensure they had local support for what will still be a trial. “Community involvement is absolutely fundamental,” he said. A huge amount of work, over years, had gone on to explain the project to people living in areas where earlier trials had taken place. “Get that sort of community intervention wrong and you never recover from that,” he said.

There are great hopes for Wolbachia but it is too soon to suppose this is the answer to the Zika and dengue epidemics. Farrar said he would wait to see whether it worked. “I’m in equipoise. I really hope it will, but I’d like to see the evidence at scale.”

Sue Desmond-Hellman, chief executive of the Bill and Melinda Gates Foundation, in London with Farrar for the latest Grand Challenges meeting where new projects are presented and funding awarded, said she agreed.

“What I feel most confident about is that it is safe,” she said. “We know that Wolbachia is already found in 60% of the world’s insects. Everyone in this room has probably been bitten by something with Wolbachia.”

Aedes aegyti mosquitoes are found across large areas of the world, including the southern part of the United States, parts of Asia and Africa. Methods to control the populations or limit the damage they can do in transmitting viral infections are urgently needed. The director of the US Centers for Disease Control and Prevention said on Tuesday that there was not yet a way to contain the spread of infections.

“Zika and other diseases spread by [the Aedes aegypti mosquito] are really not controllable with current technologies,” said Thomas Frieden. “We will see this become endemic in the hemisphere.”

More than 50 countries have experienced an outbreak of Zika virus infections since 2015, according to WHO data, and there have been nearly 2,200 cases of microcephaly – babies with brain damage – associated with Zika, 28 of which have been reported in the US. The vast majority – 2,033 – were reported in Brazil.

Mosquitos to be infected with bacteria in fight against Zika virus

Miami Beach protests against use of Naled to fight Zika-carrying mosquitos

Aerial spraying to kill Zika-carrying mosquitoes in Miami Beach is set to begin on Friday despite growing protests over the use of the controversial insecticide Naled, which is banned across Europe because of concerns over its safety.

Health officials in Florida ordered the spraying as the number of locally acquired cases of the disease continued to rise, with new figures from the state’s department of health on Wednesday recording 56 non-travel-related infections, mostly in Miami Beach and the nearby Wynwood neighbourhood.

But the decision to use Naled, a potent neurotoxin that kills mosquitoes on contact, which opponents claim can cause birth defects and which was blamed for the deaths of millions of honeybees earlier this month following aerial spraying in South Carolina, has prompted fiery protests in Miami Beach. The federal Centers for Disease Control and Prevention (CDC) says that Naled is safe.

Several hundred demonstrators, some wearing gas masks and carrying placards denouncing the use of Naled as “lunacy”, attended a lively public debate at Miami Beach city hall on Wednesday. At the meeting, county officials agreed to postpone spraying for 24 hours until Friday, but said it would be followed by another early-morning round on Sunday and others in each of the two following weekends.

“I don’t particularly want to do this, we tried everything not to get to this point,” said Carlos Giménez, the mayor of Miami-Dade County, to jeers from many in the audience.

Testing earlier this month showed that adult mosquitoes collected in Miami Beach were found to be carrying the Zika virus. The county, which has jurisdiction over Zika-fighting efforts, has until now sprayed at street level using the organic larvicide bacillus thuringiensis israelensis (BTi), which does not kill adult mosquitoes.

“We need to do this to knock down this population of mosquitoes and knock down the occurrence of Zika in Miami Beach, and stop this problem here right now,” Giménez said.

He repeated earlier assurances from Dr Celeste Philip, the Florida surgeon general, and from officials of the CDC that Naled was safe.

A CDC information sheet about aerial spraying says the insecticide has been used “extensively” in the US since the 1950s, and has already been effective in countering Zika in Miami’s Wynwood district.

But Naled opponents, including elected officials in Miami Beach, are outraged at the use of an organophosphate banned by the European commission in 2012 and sent back to the mainland by Alejandro García Padilla, the governor of Puerto Rico, in July when the CDC sent a shipment to the Caribbean island to combat the escalating Zika outbreak in the US commonwealth.

“It’s a powerful neurotoxin and the risks associated with it are unknown,” Miami Beach commissioner Michael Grieco, who hosted the public forum on Wednesday, told the Guardian.

“I don’t care if it’s been used for one week, one decade or 50 years, it means nothing when there are studies out there and the jury’s still out on whether even a low dose of Naled can be harmful to animals, children or adults. People just don’t want it.

“A lot of people are pulling their kids from school on Friday and going away for the weekend; a lot have left town and don’t plan on coming back until October. It’s a shame that people have to flee from their own homes.”

The meeting also heard from Wynwood residents, who said they had been affected by aerial spraying in Miami’s arts and design district, which is also a designated “Zika zone”.

“I’m not a scientist and I’m not a doctor, but I know that when I go in my backyard and my tongue is shaking for four hours and I am ready to rush myself to the emergency room, something in that chemical is not right,” said Evo Love, an artist with a Wynwood studio.

Further protests took place at city hall on Thursday as demonstrators stepped up their opposition to the spraying.

“If I was the county mayor, I would listen to the residents that are most directly affected,” Grieco said. “If I was using the cover, as Giménez is, that the Florida governor is going to do it anyway, I would call the governor and stand up for my people.

“I’m speaking for a lot of people and they are very unhappy. What happens if these four doses are ineffective and they want to turn this into a long-term project? I can tell you right now that this will be publicly and repeatedly readdressed if there is any inclination to go beyond the four rounds they are claiming they are going to do. The residents and myself are not going to take this lying down.”

Miami Beach protests against use of Naled to fight Zika-carrying mosquitos

Florida mobilizes to control mosquitos causing "unprecedented" Zika outbreak

A 500 square foot area in the Wynwood neighborhood of Miami, Florida is now the epicenter of the US fight against Zika, as federal and state health officials said at least 15 people were infected with the virus by local mosquitoes.

Officials said more diagnoses could be made in the coming days. The cases represent the first Zika infections transmitted by mainland American mosquitoes. The city began aerial spraying against the mosquitoes, a technique whose effectiveness is hotly criticized.

Related: Scientists edge closer to creating effective Zika virus vaccine

“Zika is unprecedented,” said Centers for Disease Control and Prevention director Dr Tom Frieden, at a press conference Thursday with Florida governor Rick Scott and state health officials. “We’ve never before had a mosquito-borne disease that can cause birth defects.”

Frieden said his top priority is to lower mosquito populations in the area. The mosquito that transmits the disease, Aedes aegypti, lives in and around homes, and can breed in containers as tiny as a bottle cap.

“It’s not going to easy, this is a difficult mosquito to control,” said Frieden. “Coffee cup, paint can, bucket for collecting rainwater … trash that can support a little bit of water when it rains” all will need to be emptied, Frieden said, and “a major effort to clean that entire effort” will be undertaken.

“What we want to see is mosquito counts coming down,” he said.

Related: Houston’s mosquito hunters take on Zika: ‘We cannot spray our way out’

Scott also repeatedly emphasized that Florida is still “safe” for the roughly 110 million tourists that travel to the state each year, even as officials warned pregnant women not to visit the Wynwood neighborhood.

Zika is believed to cause microcephaly, or abnormally small heads and severe developmental problems, in babies whose mothers are infected with the disease.

There is no specific treatment for the virus, no vaccine and little is known about how it impacts children not born with apparent birth defects. It is also sexually transmitted and can cause an autoimmune disorder that can lead to paralysis called Guillain-Barré.

Already, Miami has the longest mosquito season of any major city in the country, according to a new analysis by Climate Central. On average, just 28 days per year are inhospitable to mosquitoes in Miami, an increase of 20 days since 1980.

And although the recent infections in Miami are the first to be transmitted by local mosquitoes, cases of Zika have entered the US for months now. The CDC confirmed more than 1,800 infections in people returning to from travel. In Puerto Rico, more than 5,500 people have been infected with the virus.

Despite ample warning from experts that Zika would reach, and likely infect, American mosquitoes, Congress was unable to pass any appropriations to combat the disease.

A bipartisan effort by Florida’s senators, Republican Marco Rubio and Democrat Bill Nelson, to fund President Obama’s request for $ 1.9bn in Zika funding was quickly quashed. A Senate proposal for $ 1.1bn also failed, and a House proposal loaded with “poison pill” abortion politics riders also failed.

Instead, the Health and Human Services Administration raided other budgets to fund Zika vaccines and mosquito control efforts across the country, including monies originally allocated to fight Ebola. Already scarce dollars are expected to run out before the National Institutes of Health is able to begin the second phase of Zika vaccine clinical trials this fall.

“Now that the United States is in the height of mosquito season and with the progress in developing a Zika vaccine, the need for additional resources is critical,” HHS secretary Sylvia Burwell wrote in an 3 August letter requesting additional funding.

Public outcry has also hampered what some experts believe is one of the best answers to a complicated problem – aerial spraying. Local resistance in Puerto Rico has so far stopped fumigation with a CDC recommended chemical called naled.

The mosquito that carries Zika also carries a range of viruses, including Dengue fever and chikungunya. When Aedes mosquitoes spread Dengue fever through Puerto Rico in 1987, the pesticide naled was also used in a mass spraying campaign on the island.

The man who ran a study on that spraying, and the former head of the CDC’s dengue branch, Duane Gubler, told the University of Minnesota Center for Infectious Disease Research and Policy that the mosquito’s habitat in trash cans, closets and indoors makes mass spraying challenging at best.

“Successful spraying against Aedes depends on too many factors. Do people have their windows open? What rate is the wind speed? What is the weather?” Gubler told CIDRAP in July. “Spraying doesn’t kill larvae, and naled isn’t a residual insecticide. You’d have to spray weekly to make an impact.”

Miami-Dade county mayor Carlos Gimenez told the Miami Herald that even he had heard conflicting accounts of using naled.

“Some say it’s effective. Some say it’s not that effective. But it’s been recommended by the state and the federal government and we’re going to do it,” Gimenez told the Miami Herald.

“If it has a success rate of 10%, 20%, 30%, then that’s 30% more than what we had before.”

Even the company that makes naled admitted potential drawbacks.

“Resistance is always a potential in a living ecosystem,” Jeff Alvis, a business manager at Amvac Chemical told Chemical & Engineering News in February, about its effectiveness.

In Florida, state officials have tested 2,400 people for Zika across several counties. Officials also said that at least one other case in south-west Florida is also being investigated, but called it “unrelated”.

“As long as there is Zika spreading anywhere, pregnant women should protect themselves against mosquito bites,” said Frieden.

Florida mobilizes to control mosquitos causing "unprecedented" Zika outbreak