To Fight Deadly Dengue Fever in Humans, Create Dengue-Resistant Mosquitoes, Science, Smithsonian Magazine
To Fight Deadly Dengue Fever in Humans, Create Dengue-Resistant Mosquitoes
- 1 To Fight Deadly Dengue Fever in Humans, Create Dengue-Resistant Mosquitoes
- 2 How manipulating the immune systems of mosquitoes can halt the spread of dengue virus
- 3 How to get rid of the whitefly on indoor flowers: features of the fight against pest
- 4 What you need to know about the pest?
- 5 Causes of
- 6 A photo
- 7 How to get rid of the insect on flowers
- 8 Features of methods to combat pest grenade
- 9 Preventive measures
- 10 The U.S. Army Wanted to Conscript Insects to Fight the Viet Cong
- 11 But the six-legged soldiers weren’t terribly reliable
- 12 Buy ‘The Jasons: The Secret History of Science’s Postwar Elite’
- 13 Inside the Forever War Against Parasites Trying To Control Our Brains
How manipulating the immune systems of mosquitoes can halt the spread of dengue virus
There’s a reason this tropical disease is known as “breakbone fever”: To its victims, that’s how it feels. Dengue fever can cause such severe muscle and joint pain that it can be excruciating for an infected person to even move. It can also cause burning fever, delirium, internal bleeding and even death as the body attempts to fight off the disease. There is no effective treatment, and won’t be anytime soon.
Nevertheless, new research identifies a hope for stemming the epidemic—and it lies in genetic engineering.
Dengue virus, which is passed on by the same Aedes Aegypti mosquito that spreads Zika, has been plaguing humans since at least the late 1700s. But in the past few decades, skyrocketing human population and increased urbanization—particularly in warm, moist regions like South America, Southeast Asia and West Africa—have fueled a growing number of cases. Like the Zika virus, dengue has no symptoms for the majority of those who contract it (roughly three-quarters). But nearly 100 million people annually do develop at least some of its dangerous and excruciating symptoms—and roughly 20,000 of those die each year.
Even if you do survive dengue fever, you aren’t out of the woods yet. In fact, overcoming the disease once actually makes you more likely to die if you contract a different strain later. That’s because the various types of the virus appear so similar on the surface, that the immune system will often respond using the same antibodies it developed to fight the last bout. But these are ineffective against the new strain. Moreover, the immune system’s efforts to fight the virus can attack the body instead—causing hemorrhaging, seizures and even death.
So far, preventing the spread of dengue has mostly taken the form of old-fashioned mosquito warfare: nets, insecticide and draining still water, where mosquitoes like to breed. In 2015, researchers finally developed a partially effective dengue virus vaccine, which was green-lighted in three countries. But the vaccine only reduced chances of getting the virus by 60 percent in clinical trials, and because of the risk of developing antibodies, some experts think it may only be safe for people who have already survived an infection.
Today the vaccine is only being used in limited quantities in the Philippines. «There is really an urgent need for developing new methods for control,» says George Dimopoulos, a John Hopkins University entomologist who studies mosquito-borne diseases like malaria and dengue.
Instead of focusing on how people get infected with dengue, Dimopoulos has turned his efforts to how mosquitoes themselves contract the virus. Usually, the virus makes its home in a mosquito after the insect bites an infected human; it rarely passes between mosquitoes. So theoretically, by figuring out how to block that infection from ever occurring, you could effectively eliminate dengue virus, Dimopoulos says.
In a study published today in the journal PLOS Neglected Tropical Diseases, lead author Dimopoulos explained how that would work. Using genetic engineering, he and his team manipulated two genes that help control the immune system of the Aedes aegypti mosquito, which most commonly spreads dengue. The manipulated genes caused the mosquitoes’ immune systems to become more active when the bugs fed on blood, which is when they contract dengue virus. This stimulation made the mosquitos significantly more resistant to the different types of dengue virus.
«This impressive body of work is an important step forward in understanding mosquito-[dengue virus] immunology,» says University of Melbourne dengue researcher Lauren Carrington, who was not involved in the study.
However, Dimopoulos says this breakthrough is just the first step. While the mosquitoes in his study became roughly 85 percent more resistant to some types of dengue virus, other types were much less affected by the genetic engineering. Furthermore, the manipulation didn’t seem to create any significant resistance to the related Zika and Chikungunya viruses that Aedes aegypti also spread.
Dimopoulos hopes to fine-tune the method to make it more effective. While genetic engineering comes laden with controversy, he points out that his technique doesn’t introduce any foreign genes into the mosquitoes; it simply manipulates the ones they already have. Eventually, he hopes to create mosquitoes that will be resistant to multiple tropical diseases. He also wants to take advantage of «gene drive» technology, which enhances the chances of a certain gene to be passed to offspring, to allow the genetically modified mosquitoes to quickly become dominant in any environment they’re released into.
This isn’t the first time researchers have played with mosquitoes’ genes in an attempt to halt the spread of disease. The British biotechnology company Oxitec has worked to modify the genome of the Aedes aegypti mosquitoes to make males that produce dead offspring after mating. Brazil has already partnered with the company to release billions of these mosquitoes into the country, in hopes of suppressing the population of disease-spreading mosquitoes. The company has also worked to get approval to release its mosquitoes in other places, including India, the Cayman Islands and the Florida Keys, where Zika fears drove voters to approve a trial in a ballot measure last year.
Oxitec’s methods are effective in the short term, Dimopoulos says. But eliminating the mosquito population from an area will not make it mosquito-free permanently, because mosquitoes from other areas will eventually fill the empty niche left behind. Authorities will be forced to regularly release more genetically modified mosquitoes to keep their population numbers suppressed, Dimopoulos notes—a costly method that would appeal to biotech companies like Oxitec.
Replacing the wild mosquitoes with live but resistant mosquitoes, however, will act as a lasting barrier to spreading tropical diseases, Dimopoulos says. Before we get there, though, he says he wants to work on upping the resistance of the mosquitoes to dengue, as well as making them resistant to other types of tropical diseases. Then, he’ll need to do trials in greenhouses and on islands to see if the resistance works outside the lab.
He doesn’t expect any widespread releases of mosquitoes for another decade, but points out that 10 years is a small wait overall. «It’s not going to happen quickly,» Dimopoulos says, «but we have to remember that these diseases have been with us for a very long time.»
There’s no humane way to test in the lab whether or not humans will contract dengue less often from these mosquitoes, Dimopoulos says. As a result, we’ll only know for sure how effective the gene manipulation is once the mosquitoes have been released. But even if they don’t work as well outside the lab, Dimopoulos has no regrets about blazing new trails to combat tropical illnesses.
«The fight against these diseases is like a war,» Dimopoulos says. «You can’t win it with one weapon.»
How to get rid of the whitefly on indoor flowers: features of the fight against pest
Whiteflies are miniature flying insects that can cause significant damage to plants.
Large colonies of this pest have enough 5-7 days for the complete destruction of many ornamental or garden plants.
The leaves on the infected culture turn pale and dry, the growth of the stem stops. And not every florist or gardener can easily cope with such a scourge.
What is important to know about such plant damage and how can you get rid of the pest?
What you need to know about the pest?
The pest belongs to the class of Lepidoptera, but according to the structure of the body resembles aphids. The average length of one individual — 2-3 mm. Visually, whiteflies are white little butterflies that sit on the plant or swirl above it. The pest has 4 wings covered with white bloom. Parasites appear in the heat and high humidity (from +30 and above). In total there are more than 20 types of pest.
The most common are:
- tobacco, cotton and citrus (native to South Asia);
- greenhouse (come from South America);
- cabbage and strawberry (habitat — the average latitude of Russia).
A characteristic sign of whitefly infection is a white patina on the top of the leaf that glitters in the light. This plaque is a pest’s vital activity. It contains the causative agents of many viral diseases (jaundice, chlorosis, leaf curl). Late defecation of the whitefly can turn into a sooty fungus.
The whitefly is a heat-loving insect that lives and breeds in a humid environment. greenhouses, nurseries, greenhouses. Planted close to each other plants, poorly ventilated room — a favorable environment for the appearance of the parasite. On how to get rid of the whitefly on the plot and in the greenhouse you will learn in this article.
REFERENCE! At a temperature below 10 degrees, the whitefly dies, but its larvae remain intact (they may hibernate even at lower temperature conditions).
So, the general causes of the pest:
- contaminated soil;
- purchase of infected seeds or plants;
- whitefly penetration through a greenhouse door or window;
- lack of ventilation of the greenhouse, greenhouse (stagnant air);
- high humidity and heat.
Next you can see the pest photo:
How to get rid of the insect on flowers
To get rid of a dangerous insect, you can use several methods. Both chemical preparations, and national recipes, and mechanical adaptations are suitable for fight against the wrecker.
This is the most radical and fast method. The treated plant absorbs the active substances from the drug and becomes poisonous.. The whitefly drinks poisoned juice and dies within a few hours. Treating plants with chemicals is best 2-3 times with an interval of 7-10 days.
During the procedure, be sure to wear gloves and a respirator.
Spray the plant better in the open air.
What drugs to pay attention to? The specified dosage may vary depending on the specific type of plant, be sure to specify the proportions in the instructions or on the package.
- Pegasus. Dosage: 2 ml per 1 liter of water. Spray 2 times. In the first week, 1 time, a week later, repeat the procedure.
- Verticillin J. 25 ml per 1 liter of water. Spray 2 times in 7-10 days.
- Admiral: 3 ml per 10 liters of water.
- Biotlin, Commander, Tanrek (5 ml per 10 liters of water).
All the details about the most popular remedies for whitefly, as well as how to prepare the solution and process the plant, we told here.
How to destroy popular ways?
The effective folk remedies include decoctions of various herbs, infusions based on garlic or onions, soapy water, ash. These recipes will be effective only with a small number of pests. Also means can be used in the preventive purposes.
|Garlic or onion brew||
|Yarrow Herb Infusion||
How to deduce special traps?
Glue traps for whiteflies are made on the principle of traps for flies. They are an adhesive tape with a sticky composition of yellow or white. Getting on such a trap, the whitefly sticks and can no longer fly away, with time it dies. You can buy a trap in specialized stores for a garden. When choosing pay attention to the company Pheromone, Argus.
IMPORTANT! Before installing the adhesive tape on the plant, read the instructions and be sure to use gloves. After setting, rinse hands thoroughly with cleanser.
This is a device that eliminates flies and mosquitoes. And usually used in everyday life in order to protect the home from insects.
But farmers note that adaptation effectively and in the fight against other pests, including the whitefly.
Fumigators come with plates or with liquids. To eliminate whiteflies, it is better to take a device with a liquid, since individuals do not tolerate chemical vapors.
The fumigator should be installed next to the plant, then the room should be isolated.. The device works from the network, for convenience, you can use a network extender.
Features of methods to combat pest grenade
Exact steps and actions depend on the type of grenade. If the whitefly attacked a room grenade, the following algorithm would be appropriate.
- Take the pomegranate to the bathroom and rinse the leaves thoroughly with cold water. Wash the back of each leaf especially well, use a sponge if necessary.
- Replant the plant in another pot with new soil, dispose of the old contaminated soil.
- Put the plant in a cool place. Pomegranate is unpretentious, he likes coolness, so for a while you can even put it in the fridge. In winter — bring to the balcony or loggia. Be sure to keep an eye on the temperature — the permissible rate is not below -7 degrees.
- Pomegranate can be removed from whiteflies with the help of folk recipes (they are non-toxic, they do not pose a danger to humans and animals). When processing chemical preparations, it is necessary to isolate grenades.
If the whitefly attacked the pomegranate in the garden, a cold shower several times a day will help to cope with it. After it, you should additionally spray the tree from the spray gun. You can add a soap solution or onion / garlic infusion. With the whitefly sticky traps do an excellent job. If there is no effect, chemicals come to the rescue.
To prevent infection in the greenhouse or at home, quite regularly and accurately ventilate the room. At high humidity it is forbidden to water and spray the plant.. At home, put the pots at a distance from each other, when growing on the beds — keep a distance when planting seeds.
Prevention in the garden
- Late autumn, be sure to dig the soil. This will allow the larvae that have dug for wintering to rise to the surface.
- After harvesting, remove all plant residues outside the garden and burn.
- There should not be a compost pile on the plot. This habitat and wintering is not only whiteflies, but also other pests.
- Before planting plants in the greenhouse, its frame and cover must be disinfected with bleach. You also need to treat the soil with a solution of copper or iron sulphate.
The whitefly is a dangerous insect that is difficult to fight. But a complex of chemical, folk and mechanical methods will help get rid of the pest as soon as possible. To exclude re-infection, be sure to follow the rules of prevention.
The U.S. Army Wanted to Conscript Insects to Fight the Viet Cong
But the six-legged soldiers weren’t terribly reliable
by JOSEPH TREVITHICK
Mao Tse-Tung famously wrote in On Guerrilla Warfare that guerrillas are proverbial fish who have to swim in the water of the people in order to win their struggle against powerful governments.
“It is only undisciplined troops who make the people their enemies and who, like the fish out of its native element, cannot live,” Mao explained.
But what if a government could turn the actual wildlife in rebel areas into loyal regime soldiers?
In 1963, the U.S. Army tried to do just that. Facing swelling Communist insurgencies across Southeast Asia, the ground combat branch hoped to conscript insects to fight rebels alongside human troops.
“Wasps, bees and ants are abundant in many environments, especially in
tropical regions,” researchers working for the Army’s Limited War Laboratory wrote. “These insects are excited to a high level of aggressive behavior by the presence of minute amounts of alarm substances which provoke the insects to make fierce attacks on any invaders of the area.”
Unfortunately, the six-legged reinforcements just weren’t reliable enough for combat duties.
While humans have relied on animal labor since ancient times, armed groups generally enlisted horses, oxen and even elephants — and only to carry riders or supplies rather than to directly attack the enemy. Actual animal “weapons” — attack dogs or flaming, sap-smeared pigs — have played very limited and specialized roles on the battlefield.
The U.S. Army had grand ideas of deploying the local fauna in places such as South Vietnam to harass or kill militants hiding in the countryside. The animals would ambush the ambushers.
At first, researchers didn’t focus on any specific type of creature for the project. But by December 1963, the Army had decided insects were ideally suited to its plans.
The Army’s idea was to fill small capsules with a chemical that would anger, or at least attract, biting or stinging bugs. The containers would be fragile enough that they would break open if anyone stepped on them.
Troops would spread the vials anywhere they figured guerrillas might hide. And the same soldiers could scatter the bug-pills around bases and camps to protect themselves.
“The triggered agent would be virtually undetectable by an enemy,” the Army scientists wrote.
In addition, the ground combat branch was interested to see if similar substances could attract disease-carrying critters to enemy food stashes. And if the chemicals drew out certain bugs, insurgents — covered in insects — might stand out in villages or cities.
“As one approach, the possibility of employing ‘fly factor’ as a means of promoting contamination … should be studied,” one 1963 status report stated. “A second approach would involve the use of cockroach sex-attractant in various ways, including promoting contamination and for personnel-marking and identification.”
The Army also conducted separate research into using insect-filled machines to spot insurgents deep in the jungle. At the same time, the service cooked up purely chemical-based “people sniffers” that, unlike the bug-bombs, actually did make their way to South Vietnam.
In 1965, the scientists at Cornell University put the basic principles of the insect booby-traps to the test. Their subjects were ants and honey bees. In their laboratories, researchers examined how the insects responded to the chemicals. Outdoor tests looked at how far those substances spread — and how well they stuck to people.
With the ants, “results were inconclusive,” according to one progress report. Undeterred, the researchers continued to try for “significant enhancement of aggressive behavior” among the bugs.
The next year, the Army ironed out a new deal with Cornell. According to the ground combat branch, the university had proved the underlying idea was sound and that the insects acted as one might expect them to.
Buy ‘The Jasons: The Secret History of Science’s Postwar Elite’
Under the new contract, the research team would cook up chemicals to attract apis dorsata, the giant honey bee that’s native to South and Southeast Asia. These stinging insects can grow to nearly an inch long.
In June 1966, Cornell was supposed to have started a test somewhere in Asia to see if the scheme was ready for actual combat-deployment. But three months later, the Army totally canned the project. The military had spent nearly $35,000 on the idea, equal to more than $250,000 in 2016.
We don’t know the exact reason why, but it seems that the insect soldiers simply wouldn’t do what they were told. Apparently, getting them agitated just wasn’t enough.
“Studies tend to confirm results reported in the literature concerning the stimulatory effect of various compounds on bees and ants,” is all the 1974 summary had to say about the final results.
Before cutting loose its bug soldiers, the Army had already quietly stopped work on the other insect-based infiltrators and sentries. However, the studies into using bugs to find hidden guerrillas — or catch them trying to sneak into a camp — continued for some time afterwards.
As with other exotic Pentagon plans, the Army clearly decided that more conventional weapons such as landmines and flares worked as intended when they were needed — unlike an unpredictable force of unwitting, six-legged conscripts.
Inside the Forever War Against Parasites Trying To Control Our Brains
Insidious organisms have spent tens of millions of years trying to hijack their hosts’ bodies – and behavior. But one researcher wants to know just how much have brains changed to fight the threat.
Some of the most insidious and ancient threats to animals on Earth are parasites that hijack the bodies and brains of their hosts for their own nefarious ends. Now researchers are starting to gather clues about how this longstanding battle shaped some of the most basic functions of the animal brain.
Psychologist Marco Del Giudice, of the University of New Mexico, recently published a comprehensive review of the research into the war between parasites and their hosts. “I don’t do empirical research with parasites,” Del Giudice explains to Popular Mechanics . “I was interested in the implications for psychology and neuroscience.”
Called “Invisible Designers: Brain Evolution Through the Lens Of Parasite Manipulation,” Del Giudice’s review argues that relentless parasitic assault has likely shaped their hosts’ nervous and endocrine systems.
“Millions of years of attacks by manipulating organisms must have exerted a powerful selective pressure on brain evolution in animals,” he writes in the Quarterly Review of Biology, a peer-reviewed publication that’s been around since the 1920s.
This is what Del Giudice uncovered about the secret war that’s been unfolding in our brains for millions of years.
Puppet Master Pathogens
It may seem impossible for something as simple as a unicellular organism to take control of a higher-order life form, but you can spot the phenomenon frequently in nature. Rats have an innate, instinctive reaction to the odor of a feline that says, “stay away.” This makes basic evolutionary sense, but a rat infected with the one-cell parasite Toxoplasma gondii doesn’t act that way.
The parasite has a goal—gain access to where it thrives, otherwise called the “definitive host.” In this case, it wants to build a home inside a cat.
Rats infected with Toxoplasma gondii lose their aversion to the scent of cats, greatly improving the odds that they will be killed and the parasite will migrate. Some researchers have seen that the rats even become attracted to the scent and hasten their doom (to the parasite’s advantage).
«Parasites can penetrate inside the brain and attack it from within or secrete neuroactive compounds that will reach the brain through circulation.»
But how are these parasites able to do this? It’s not intelligent thought and it’s not magic— It’s chemistry. The brain’s neurons communicate via chemical signals, so it’s imperative for parasites to insert themselves into that process. That means sneaking compounds into the brain, one way or another.
“Parasites can penetrate inside the brain and attack it from within or secrete neuroactive compounds that will reach the brain through circulation,” says Del Giudice. “In both cases, they need to get past the blood-brain interface and its defenses.”
When a frontal assault fails, a parasite may take an indirect route to send its own self-serving chemical signals into a brain. The body and brain swap information via the chemicals released by endocrine organs like the thyroid and gonads, as well as parts of the immune system. A parasite may lodge itself inside an organ or manipulate it from the outside. “The hormones produced by these organs modulate brain function and can powerfully affect behavior,” Del Giudice says.
That puts the entire central nervous system—not just the brain itself—on the frontline. “Endocrine systems are not just a potential target for hijacking,” Del Giudice says. “Parasites can eavesdrop on the host’s hormonal signals to gain precious information about the state of the organism and respond adaptively.”
There are plenty other dramatic examples of animals being puppeteered by manipulative parasites. Ants infected by a roundworm called Myrmeconema neotropicumturns turn from black to red and strike suicidal berry poses that attract hungry birds, the worm’s definitive host. Some sick fish lose motor coordination and become easier prey, spreading the parasites. Rabid animals resist water, froth at the mouth, and become aggressive, the perfect conditions for a saliva-bourn pathogen to spread.
“Many sexually transmitted microbes regulate their growth in response to sex hormone levels,” he notes.
In other words, the parasites marshal their forces and get ready to strike when the reproductive irons are hot. It’s a level of sophistication that you might not expect from a microorganism.
Battles on the Blood Brain Barrier
Parasites have been trying to hijack animals for a long time—and that’s actually a good thing.
“Fossilized ants show that present-day manipulation strategies by fungi and helminths [worms] were already well established around 30 to 50 million years ago, suggesting that they originated much earlier,” Del Giudice says.
Luckily for animal life, long centuries of exposure to hostile parasites has led to defenses that makes brains harder to hijack. Del Giudice says that there could be many more of these polymorphic matchups locked into our DNA but infused into our programming before humans even evolved, in some cases “possibly in the early stages of brain evolution.”
«Many aspects of neurobiology are destined to remain mysterious or poorly understood until parasites—the brain’s invisible designers—are finally included in the picture.»
The presence of parasites in such deep parts of pre-history, shaping the animal genome at its most basic level, is why Del Giudice feels they could be forgotten drivers of early, fundamental evolution.
“Many aspects of neurobiology are destined to remain mysterious or poorly understood until parasites—the brain’s invisible designers—are finally included in the picture,” he writes.
Recent research indicates that this fight is being waged inside human beings. One of the newest insights into this shadowy fight is Wolfgang Zimmerman’s Evolution: Decoy Receptors as Unique Weapons to Fight Pathogens which published in December 2018. The paper describes a duel between bacteria and the human brain for control of the immune system.
Zimmerman studied molecules called CEACAMs, receptors with the main function of gaining entry to the brain to prompt inhibitory immune system responses. Some bacteria release mimic compounds that appears to be CEACAMs, imposters cross the blood-brain barrier and hack the immune system to thwart a response.
But the human body is not defenseless. Zimmerman’s paper examines the body’s production of decoy CEACAMs that specifically attract the fake, parasitical molecules. These are marked for targeting and destruction.
The discovery of these decoys “points to an evolutionary process that allows the host to catch up with pathogens,” according to Zimmerman. As a sign of how intense this invisible battle has become, the decoy, called CEACAM3, is one of the fastest-evolving genes in the human genome.
A Modern Battlefield
The influence of parasites on evolution — the results of millennia of biochemical conflict — could have modern implications. Knowing how to help the body defend against parasites is only one part of the equation. Just like the parasites, humans are trying to hack the human brain.
Knowing how to shuttle chemicals across the blood-brain barrier is critical in developing drug treatments for mood disorders. “If the human brain contains evolved countermeasures to manipulation,” writes Del Giudice, “The implications for psychopharmacology could be profound…standard pharmacological treatments may unwittingly mimic a parasite attack and trigger specialized defensive responses.»
Another lesson parasites can teach us comes from a ghastly parasitic example where wasps chemically groom cockroaches to be their victims.
The wasp has no lessons to teach when it comes to crossing the blood-brain barrier; it simply injects a chemical cocktail directly into the head of a cockroach, pumping the insect’s ganglia with a mix of dopamine, octopamine, opioid receptors.
Under the influence, the cockroach compulsively cleans itself for a half hour as the wasp prepares a nest. The wasp returns to find an exhausted roach, mutilates its antenna, and leads it back to the nest, where the cockroach then sits still as the wasp lays its born-voracious larva inside its body.
This vivid and disturbing example points to the effectiveness of parasites that don’t rely on just one chemical to gain access to the animal brain. Successful parasites tend to gain access by using several chemical pathways, instead of specializing in just one.
There is also a tendency to stagger the attacks, preparing for the major intrusion with a chemical barrage that sets the field to their advantage. Like artillery battering defenses on a military battlefield, some parasites spur the host’s production of dopamine that interferes with defensive reaction, before releasing the intruding chemicals meant to infiltrate the brain or nervous system organ.