dengue stopped with bacteria and GMO

Highlights
An idea now aims to produce a vaccine for all these diseases in a single go. For this, a novel ingredient is being looked at - mosquito spit
The results of the trial were found to be safe for use in humans, with an ability to trigger antibody and cellular responses in the human body
Instead of targeting the pathogen that causes the disease (like malaria), the vaccine is based on the vector that transmits the disease (like mosquito)
Spread through mosquitoes, malaria was responsible for 435,000 deaths in 2017 as per WHO. Almost 80 percent of these deaths occurred in the WHO African Region and India.

Apart from malaria, such mosquitoes have been responsible for spread of diseases like dengue, chikungunya, Zika, yellow fever, West Nile, Mayaro viruses and any possible new ones.


An idea now aims to produce a vaccine for all these diseases in a single go. For this, a novel ingredient is being looked at - mosquito spit.

Birth child of Jessica Manning, a clinical researcher for the U.S. National Institute of Allergy and Infectious Diseases, the idea aims to use the protein in mosquito saliva to build a universal vaccine for diseases spread through the insects.

Mosquito Spit, Mosquito Saliva Vaccine, Vector Based Vaccine, Malaria Vaccine, Zika Vaccine, Covid-19 News, Technology News
A giant sculpture of a mosquito is pictured in the courtyard of scientist Jessica Manning’s lab space, near Phnom Penh, Cambodia (Image: Reuters)


Working on the vaccine with her colleagues, Manning has now been able to conduct the first ever clinical trial of a mosquito spit vaccine in humans. As per the results published by The Lancet, the trial has had a positive response.

Authorities have confirmed a dozen cases of Zika virus in the United States. Here's what you need to know. (Gillian Brockell/The Washington Post)
Brazil is latching onto a novel, if controversial, approach to fight the spread Zika virus: genetically modified mosquitoes.

Zika virus is transmitted to humans primarily through the bite of an infected Aedes species, such as Aedes aegypti, the yellow fever mosquito.

No vaccine or treatment exists to combat the infection, which public health officials are worried may be linked to a brain defect in infants and a rare neurological syndrome that could cause paralysis in adults. The World Health Organization has expressed alarm at the explosive spread of the virus in the Americas in recent months and says as many as 3 to 4 million people could become infected.

[Zika scare: Airlines and cruise companies offer refunds to pregnant women]

Releasing even more of these insects into the wild seems like the last thing a Zika-stricken country needs, but Brazil’s National Biosafety Committee recently approved multiple releases of genetically modified Aedes aegypti throughout the country. Essentially, the plan is to turn their own species against them.


A researcher looks at Aedes aegypti mosquitoes kept in a container at a lab of the Institute of Biomedical Sciences of the Sao Paulo University, on Jan. 8, in Sao Paulo, Brazil. (Nelson Almeida/AFP/Getty Images)
Created by Britain-based Oxitec, a spin-off company from Oxford University that is a subsidiary of Intrexon Corp., these mosquitoes contain a self-destruct mechanism within their DNA in the form of an inserted gene. This gene produces a protein called tetracycline repressible activator variant (tTAV), which ties up the cell's machinery and prevents the expression of other genes key to survival. As a result, the insect dies before it reaches adulthood.

But if reared on a diet with a special antidote — the antibiotic tetracycline, which binds and inactivates tTAV — the self-destruct mechanism will never switch on.

[WHO: Zika virus could explosively spread, level of alarm extremely high]

Oxitec feeds its genetically modified mosquitoes tetracycline so they can survive and reproduce in the lab. For pest control purposes, mature males carrying the self-destruct gene are gathered up and released into the wild to mate with females. Offspring who inherit the gene will die without the tetracycline antidote, causing the mosquito population to drop drastically — and hopefully with it, the threat of disease.


“We've trialed this technology in the Cayman Islands, in Brazil and in Panama through four different trials, and we have shown up to 99 percent control of the mosquito population,” said Derric Nimmo, Product Development Manager at Oxitec, in a company video. In April, Oxitec started releasing its so-called “self-limiting” mosquitoes in Piracicaba, a city in the Campinas region of São Paulo state, and reported an 82 percent reduction in wild larvae by the end of the calendar year.

Why the U.S. is unlikely to get these mosquitoes

Because Aedes aegypti is considered the primary vector for dengue, Chikungunya and Zika viruses, the company has focused extensively on this species for public health applications. For surveillance purposes, its mosquito products also contain a heritable, fluorescent marker to differentiate between altered insects and wild ones. Monitoring the ratio of genetically modified vs. wild mosquitoes in traps after a release can help gauge whether more product is needed to further suppress the pest population.

This genetic approach and others — for instance, those that render insects infertile or disease-resistant — represent a new spin on the classical Sterile Insect Technique (SIT). During the 1930s and 1940s, the idea of SIT was conceived as a method of “birth control” for unwanted insect species. Males would be rendered sterile by exposing them to massive amounts of radiation, then released to mate with females. SIT was used to eradicate the screwworm, a deadly parasite of livestock, from the United States in the 1950s, and to tame pink bollworm moth populations in California's cotton fields since 1967.

[Zika virus FAQ: What is it, and what are the risks as it spreads?]

Oxitec's scientists have also created self-limiting versions of common agricultural pests in the hopes of minimizing crop losses. One example is the diamondback moth, an insecticide-resistant nuisance that feeds exclusively on brassicas, such as broccoli and cabbage. Oxitec and Cornell University are planning field tests to be conducted in the summer in upstate New York, which have been granted approval by the U.S. Department of Agriculture.


One big question is whether manipulating the ecosystem in this way will have unintended, negative consequences.

Oxitec has come under criticism from various environmental groups that remain concerned about the possible effects of releasing a new strain of organism into the wild. For instance, a drastic drop in mosquito population could lead to harmful insects or other animals multiplying uncontrollably.

Supporters of genetically modified insects say self-limiting species target only one species, can still be eaten safely by predators, and are more effective/safe than insecticides. Also, the altered males and their offspring die off quickly due to the tTAV gene.

“In that sense, we're only removing Aedes aegypti and nothing else from the environment,” Nimmo said. “It's pinpoint accuracy. It's going in with a scalpel and taking away Aedes aegypti, leaving everything untouched.”

Miami (AFP) - A British company's plan to unleash hordes of genetically modified mosquitoes in Florida to reduce the threat of dengue fever and other diseases has sparked an outcry from fearful residents.

As of Friday, more than 145,000 people had signed a petition at change.org urging regulators to "say no" to allowing the tourist-friendly fishing and diving haven to become "a testing ground for these mutant bugs."

The company, Oxitec, said it wants to try the technique there in order to reduce the non-native Aedes aegypti mosquitoes in south Florida and beyond.

"They are more than just a nuisance as they can spread serious diseases such as dengue fever and chikungunya," Oxitec said on its website.

The process involves inserting a gene into lab-grown, male Aedes aegypti mosquitoes. The added DNA makes it impossible for their offspring to survive.

Since the males do not bite -- only the females do -- the lab-grown males would be released to mate with wild females. These releases would take place a few times per week.

"Both the released mosquitoes and their offspring will die -- they do not stay in the environment," Oxitec said, describing the approach as "a new tool in the fight against mosquitoes."

Trials conducted in the Cayman Islands and Brazil showed a more than 90 percent drop in mosquito populations, according to the company.

Based on those results, the Florida Keys Mosquito Control District agreed to work with Oxitec, which has built a breeding lab in the Florida Keys.

But the project still needs approval from the Food and Drug Administration to move forward.

If it does get the green light, the mosquito releases could begin in a few months.

- Opposition -

Opponents cite concern for the environment, and worry whether other creatures -- including bats and people -- might be affected by the introduction of the mosquitoes.

"Where is the third-party, peer-reviewed research on effectiveness and safety of GM mosquitoes other than Oxitec's own claims of success?" asks the petition.

"Dengue fever has been absent from the Florida Keys for years, which indicates the current methods of control and public education are working. What's the rush for this radical approach?"

However, health experts say that dengue is still a concern, as is chikungunya virus, which causes debilitating pain, fever and joint aches.

In July 2014, a Florida man who had not recently traveled outside the country became the first person in the United States to get the mosquito-borne chikungunya virus locally, and authorities say such cases are likely to become more common.

- Pest control -

As a means of pest control, the concept of releasing sterile males into the environment is not new, according to Joe Conlon, a technical advisor for the American Mosquito Control Association, which has not taken an official position on whether or not to support the Oxitec project.

In the 1950s, flesh-eating parasites known as screw worm flies were sexually sterilized via radiation, and the male flies were released in Florida to cut down the population.

"It worked. It worked wonders," Conlon told AFP.

Irradiation doesn't work as well in fragile mosquitoes, but genetic modification can help curb breeding of a mosquito that reproduces mainly near people -- in standing water and even inside houses.

It is not a means for total eradication of mosquitoes, nor is it meant to substitute for pesticides, though some hope it could lead to less use of chemicals in the environment.

Conlon attributed the opposition to the Oxitec plan to a lack of understanding on the part of the US public.

"It's going to be a hard sell to the American public, who get their ideas about genetic issues by watching 'Jurassic Park,'" he said.

"When they are presented with something they don't understand, they immediately fear it."