pest-control

See Fire Ants Create Towers From Their Own Bodies

To gain insights on how to program swarms of tiny robots, scientists are studying one of nature’s most cohesive species—fire ants.

When the insects work together, they’re a force to be reckoned with. The small creatures are capable of using their bodies to create towering structures of more than 30 stacked ants and buoying themselves into a raft so buoyant it stays afloat even when a human hand forces it under water.

Researchers at the Georgia Institute of Technology have been working for years to analyze how ants socially and physically form such elaborate globs without a leader or a discernable overall plan.

In a study recently published in the journal Royal Society Open Science, high-speed cameras show ants banding together to form a tower around a slippery rod. The coordination results in a bell-shaped structure, similar to that of the Eiffel tower.

Scientists had previously observed ants creating these towering structures from their own bodies, and the video offers a fresh look at the phenomenon.

The process to create these towers is less of a delicate dance and more trial and error. According to the study, an individual ant is capable of supporting as many as three other ants, which it connects to using sticky pads on its feet.

If an ant takes on more weight than it can bear, the ants fall away from the tower like a cascading avalanche. By continuously scrambling over each other, the ants are able to eventually build a solid base, building on each other from the bottom up.

Scientists believe this behavior is used as a temporary structure after events like floods. Scaling tall structures allows them to hunt for empty spaces in which they can create new homes.

Because the ants are continuously sinking, they must repeatedly climb over each other until they reach shelter, making their towers dynamic rather than static.

“The ants are circulating like a water fountain, in reverse,” one of the study’s authors told Nature.

Unsinkable Ants
The dynamics of their static structures was discovered by the same research group in 2014 when they studied how ants formed such robust raft structures.

By swirling a bunch of ants into a cup, the ants naturally formed a dough-like ball by grabbing onto each other with their sticky legs. Forming perpendicular to one another, the ants were able to evenly distribute their weight, creating a raft that floated even when one of the researchers fully submerged it in water.

While not known to be particularly intelligent as individuals, ants are adept at collectively working and communicating through a complex system of pheromones and sounds inaudible to the human ear.

Researchers hope that small robots can be programmed to form rafts and bridges of their own.

“Imagine robots that need to construct a barrier or patch a hole during a disaster response,” one of the 2014 study’s authors told Nature.

Source: NATIONAL GEOGRAPHIC

H1N1 bigger killer than dengue and malaria in Maharashtra

Mumbai: The H1N1 influenza virus which entered the list of infectious diseases with a global pandemic in 2009, has overtaken dengue and malaria to become the biggest killer among seasonal ailments in Maharashtra.

Since its appearance, the viral infection has claimed nearly 2,500 lives in the state, about five times the fatalities caused by dengue and three times that of malaria in the same period. The viral infection is now next only to tuberculosis and AIDS in the state’s list of top contagious killer diseases. TB and AIDS together are responsible for more than 10,000 deaths in the state annually.

While annual death toll of dengue and malaria have reduced to double digits over the years, H1N1, initially called swine flu, has managed to spring a surprise almost every alternate year, killing hundreds. In the first half of 2017 alone, 247 people died of the airborne disease in Maharashtra, including 10 in Mumbai. Three deaths occurred in the last week, two of the victims being a pregnant woman and another a TB patient.

Dr A C Dhariwal, director of National Centre for Disease Control (NCDC), said HINI “has indeed changed the way we used to tackle viral fever in the country. Apart from Maharashtra, Gujarat and Kerala are also badly affected”.

In January-June this year, H1N1 claimed more lives in Maharashtra than malaria which has caused one fatality and dengue two.

The resurgence comes after a lull in 2016 when far fewer deaths (26) were reported. In 2015, the state had witnessed its worst outbreak with 905 deaths.

Experts say its mode of transmission—through infected droplets released into the air—makes control or prevention almost as challenging as in the case of tuberculosis. “In dengue and malaria, we can attack the vector and control the disease. But your combat tools are limited when the fight is against an airborne disease that provides a limited window to treat,” said Dr Satish Pawar, head of Directorate of Health Services (DHS), Maharashtra.

Pawar says tuberculosis, except the cerebral type, takes at least a few years to take a life-threatening form, whereas H1N1’s progression is exceptionally rapid. “Doctors often tend to wait for test reports, which is costing us lives,” he said, explaining why a viral disease is causing such a high number of casualties. In addition, he says, mostly people with underlying health problems are succumbing to the disease.

Infectious disease expert Dr Om Srivastava said clinical challenges of treating H1N1 are unique. “The antiviral oseltamivir works for most cases, but some patients who deteriorate despite treatment,” he said, adding dengue and malaria no longer pose the threat they did even a few years ago. “Dengue has less than 1% mortality and less than 3% hospitalisation rate if all basics of treatment are followed. In H1N1, however, mortality could go up to 20% if treatment has not been started in the first five days,” he said.

Epidemiologist Dr Pradeep Awate though feels much of the hype around H1N1 is because of enhanced surveillance. “We keep a count of every single case and death. In my personal opinion, TB is a much bigger public health problem, and if drug-resistant cases keep growing we may have to go back to the TB asylum era,” he said. “But of course it’s true that influenza surveillance began only after H1N1,” he added.

A senior physician from KEM Hospital said, “All these decades we lost countless lives to seasonal influenza, but didn’t know the magnitude. These numbers should force the government to design vaccination plans and build awareness campaigns around coughing etiquette or hand-washing,” the doctor said, adding the government needs to allocate more funds for influenza control.

Source: THE TIMES OF INDIA

Beware of repeated dengue afflictions

Docs Warn That Fatality Risk Increases Due To Reaction Between Antibodies Present In The Body From Primary & Secondary Infections
Even as dengue ravages Kerala, health experts are confused by the uncommon traits and complications that were recently observed in patients.

The pattern of dengue deaths also indicates that mortality rate was high among patients who were repeatedly diagnosed with the disease.

If a person gets dengue for the first time (type-I), proper rest and medication will help in combating fever and antibodies will be generated in the body that will give life-long immunity against the type-I variety. But, when the same person is exposed to mosquito bites and gets dengue (type-II or type-III), a new set of antibodies will be generated in the body. Antibodies generated in the primary infection and secondary infection react, resulting in grave complications that may even lead to the death of the patient.

Through virus uptake and replication, type-I antibodies will intensify and complicate the typeII virus by a process called antibody dependent immune enhancement. “When a person is tested positive for dengue, prescribed antibiotics will only treat the symptoms of fever and not the virus.Like any other viral fever, dengue virus will subside and antibodies will be generated in a week. When a person is affected by dengue twice or thrice, the reaction of subsequent antibodies will lead to internal bleeding and cause dengue haemorrhagic fever or dengue shock syndrome that may lead to death,” said associate professor of community medicine at Thiruvananthapuram medical college Dr Althaf A.

The scattered information and diagnoses are yet to be compiled and analysed by authorities. Sources in the health department said there was no proper database or research on such complexities.

“When autopsy was conducted in a suspected case of dengue death in 2013, we found that the person was suffering from West Nile fever, a mosquito-borne disease. Similarly , all reported deaths might not be due to dengue. We are unable to contain deaths as scientific analysis and research are lacking,” said Dr Althaf.

There are four different strains of dengue and for a person repeatedly afflicted with dengue, the risk factor goes up. “Severe internal bleeding or blood loss can occur due to the reaction of antibodies already present in hisher body . This is a matter we have to address through research,” said former state nodal officer (communicable diseases) Dr Amar Fettle.

Genetic mutation in disease causing virus is also suspected to be one of the major reasons for the increase in fatalities, said experts. “The spontaneous changes in genetic coding of dengue causing virus can be one of the reasons for the complications.Similar to the mutation seen in H1N1 virus, dengue causing virus is suspected to have undergone genetic mutation. H1N1 virus was seen only in animals at first, it later it was transmitted to humans and by 2008, due to mutation, H1N1 virus was transmitted from one human to another,” said Dr Althaf.

Doctors, who treat dengue, have also no ticed the change in symptoms. “Many patients who seek treatment for diarrhoea; throat pain and vomiting are later diagnosed with dengue. The symptoms were high fever, back and abdominal pain. It is not the same now,” said a doctor at the general hospital in the capital on condition of anonymity .

“The Aedes aegypti mosquitoes are responsible for the outbreak.These mosquitoes can cause chikungunya, yellow fever and Zika fever.Our environment is very receptive to these diseases and we are vulnerable,” he said.

Dengue cases have risen in Thiruvananthapuram, Kollam, Alappuzha, Palakkad, Malappuram and Kozhikode this year and the disease has become round-the-year problem over the past three years.

Source: THE TIMES OF INDIA

Mumbai:53 year old woman dies of lung infection from fungi in pigeon droppings

Last year, when 26-year-old Naitik Zota took his mother Jayshri (53) to a pulmonologist following a severe about of breathlessness, the doctor confronted him with a bizarre question: Do you have pigeons in the vicinity of your home? When Zota told him about the presence of a kabutarkhana next door, the doctor advised him to place nets on the windows of his home, and move Jayshri to a room that wouldn’t be frequented by the birds. The advice, unfortunately, came late.

A few weeks later, Jayshri died of a lung infection, which the doctor alleges was the result of harmful fungi present in pigeon droppings.

Several residents of Neelkamal Cooperative Society in Borivli East, where Jayshri lived, say they too have been victims of ill health for the last eight years since the kabutarkhana came up close to their homes. They have complained of lung infection, breathing problems and asthma. After repeated complaints to local bodies fell on deaf ears, the society members filed a complaint with the BMC health department last month, demanding immediate action against the growing menace. But, the BMC is yet to act on their complaint.

Last year, when 26-year-old Naitik Zota took his mother Jayshri (53) to a pulmonologist following a severe bout of breathlessness, the doctor confronted him with a bizarre question: Do you have pigeons in the vicinity of your home? When Zota told him about the presence of a kabutarkhana next door, the doctor advised him to place nets on the windows of his home, and move Jayshri to a room that wouldn’t be frequented by the birds. The advice, unfortunately, came late.

A few weeks later, Jayshri died of a lung infection, which the doctor alleges was the result of harmful fungi present in pigeon droppings.

At Jaslok, Dr JR Shah, consultant pulmonologist, attribute her illness to pigeon droppings. “But, by then, my mother’s lung capacity had decreased by 40 per cent,” said Zota of his mum, who succumbed a few weeks later. “In severe cases, patients develop interstitial fibrosis that causes irreversible scarring of the lungs, like it happened with Jayshri. It affects the exit and entry of air to the lungs. This happens when a person lives in close proximity to pigeons or hens. I get five to six such cases every year,” said Dr Shah, referring to what’s probably a city-wide menace.

Residents at risk
“The kabutarkhana is causing health problems and many people are suffering from respiratory diseases. The physicians to whom these people consulted have opined to get rid of the pigeon feeding that starts every morning (sic),” reads the complaint copy. More than 40 residents have also submitted a petition.

Hitesh Upadhayay, a resident of the society, said that around three months ago, his wife suddenly developed trouble breathing. “There is a Jain temple inside the society where devotees come and feed the pigeons. The feeding continues till late evening,” said Upadhayay.

Medical experts recommend that patients with low immunity or history of respiratory problems should stay away from pigeon breeding grounds.

Dr Balwant Samant, a retired professor with KEM Hospital, explained that the problem is caused due to exposure to the soil, where the pigeons leave their droppings. When the droppings dry and scatter in the soil, microscopic fragments from it break away and become airborne. “These particles contain dormant fungi and bacteria that people around end up inhaling. It gets inside the lungs and becomes a breeding ground for infectious agents.”

BMC clueless
In 2016, when the issue raised in a BMC meeting, authorities had proposed to add fertility control pills in pigeon food to control the population. There has been no progress so far.

A senior health officer from the BMC, said, “People consider feeding pigeons a religious act. Most kabutarkhanas in the city are illegal, and usually near places of worship. We have been dissuading residents from feeding pigeons.”

When mid-day reached out to Dr Padmaja Keskar, health officer, BMC, she said she would look into the matter.

Source: MidDay

Battle mosquitoes vigorously

India’s dengue deaths have long called for controlling mosquitoes through source reduction at breeding sites.

The WHO report describing the first Zika virus cases is important as it provides evidence of the virus circulating in India. While the Gujarat government says there’s no need to panic over the state’s three occurrences, it’s clear India must take greater precautions, more in areas where the Aedes mosquitoes are significantly present. The virus, which has no cure or vaccine but is not known to be deadly like dengue, was first found in India in 1964. It is known since 2015 that a virulent version, which swept the world and affected the Rio Olympics last year with some athletes withdrawing, could be headed for India as the more benign strain was within some people, and could prepare genetic grounds for the second coming.

Mosquito-borne diseases like malaria, dengue and chikungunya have taken more lives than other forms of pestilence. India’s dengue deaths have long called for controlling mosquitoes through source reduction at breeding sites. And yet the Gujarat CM took the pedantic line that there was no Zika patient in his state now as the three known cases were already treated. As none of the three had travelled abroad, it is likely the infection was picked up locally. However, the presence of Aedes aegypti and Aedes albopictus mosquitoes, which are active during daytime, and the general overcrowding, lack of hygiene and very warm summers are known to be grounds for an expanding threat. There has fortunately been no case yet of microcephaly (small head and brain in new-borns), but the war on mosquitoes must be fought with increased vigour.

Source: DECCAN Chronicle

Insects resist genetic methods to control disease spread, study finds

The research, reported in the journal Science Advances, combines advanced genetic and statistical analyses to show how certain genetic and behavioral qualities in disease-carrying insects, like mosquitoes, make these species resistant to genetic manipulation.

This resistance could complicate attempts to use CRISPR-Cas9 in the fight against malaria — a deadly mosquito-borne disease that threatens over 3 billion people worldwide — or crop blights such as the western corn rootworm, an invasive species that costs the U.S. about $1 billion in lost crops each year.

The discovery of the CRISPR-Cas9 system — or simply “CRISPR” — in the early 2010s introduced an unprecedented level of accuracy in genetic editing. Scientists can use the method to design highly precise genetic “scissors” that snip out and replace specific parts of the genome with sequences of their choosing. Two English scientists were the first to show the method could spread infertility in disease-carrying mosquitoes in late 2015.

“We found that small genetic variation within species — as well as many insects’ tendency to inbreed — can seriously impact the effectiveness of attempts to reduce their numbers using CRISPR technology,” said Michael J. Wade, Distinguished Professor of Biology at IU Bloomington. “Although rare, these naturally occurring genetic variants resistant to CRISPR are enough to halt attempts at population control using genetic technology, quickly returning wild populations to their earlier, ‘pre-CRISPR’ numbers.”

This means costly and time-consuming efforts to introduce genes that could control insect populations — such as a trait that causes female mosquitoes to lay fewer eggs — would disappear in a few months. This is because male mosquitoes — used to transmit new genes since they don’t bite — only live about 10 days.

The protective effect of naturally occurring genetic variation is strong enough to overcome the use of “gene drives” based on CRISPR-based technology — unless a gene drive is matched to the genetic background of a specific target population, Wade added. Gene drives refer to genes that spread at a rate of nearly 90 percent — significantly higher than the normal 50 percent chance of inherence that occurs in sexually reproducing organisms.

Wade, an expert in “selfish genes” that function similarly to gene drives due to their “super-Darwinian” ability to rapidly spread throughout a population, teamed up with colleagues at IU — including Gabriel E. Zentner, an expert in CRISPR-based genetic tools and assistant professor in the Department of Biology — to explore the effectiveness of CRISPR-based population control in flour beetles, a species estimated to destroy 20 percent of the world’s grain after harvest.

The team designed CRISPR-based interventions that targeted three segments in the genome of the flour beetle from four parts of the world: India, Spain, Peru and Indiana. They then analyzed the DNA of all four varieties of beetle and found naturally occurring variants in the targeted gene sequence, the presence of which would impact the effectiveness of the CRISPR-based technology.

The analysis revealed genetic variation in all four species at nearly every analyzed DNA segment, including a variance rate as high as 28 percent in the Peruvian beetles. Significantly, Wade’s statistical analysis found that a genetic variation rate as low as 1 percent — combined with a rate of inbreeding typical to mosquitos in the wild — was enough to eliminate any CRISPR-based population-control methods in six generations.

The results suggest that a careful analysis of genetic variation in the target population must precede efforts to control disease-carrying insects using CRISPR technology. They also suggest that the unintended spread of modified genes across the globe is highly unlikely since typical levels of genetic variation place a natural roadblock on spread between regions or species.

“Based on this study, anyone trying to reduce insect populations through this method should conduct a thorough genetic analysis of the target gene region to assess variation rates,” Wade said. “This will help predict the effectiveness of the method, as well as provide insight into ways to circumvent natural genetic variation through the use of Cas9 variants with an altered sequence specificity.”

Source: ScienceDaily

Fly landing on food have health risks, according to experts

They are one of the scourges of summer and have been ruining picnics since the dawn of time (probably).

Flies – harmless but incredibly annoying, most people think.

But it turns out the insects may be a lot more dangerous than we thought.

The average fly carries 200 different types of harmful bacteria, largely thanks to the various things they land on, such as rotting food and fecal matter.

Even if you swat one away as soon as it’s landed on your sandwich, the damage has already been done.

Thanks to thousands of tiny hairs on their arms and legs, the bacteria are quickly transferred to your food, which could pose a serious health risk according to a pest control expert.

“They only need to touch your food for a second for their legs or the tiny hairs all over their bodies to transfer germs from all those nasty things they eat onto what you are eating,” Ron Harrison, an entomologist and technical services director at Orkin pest control, told the Mail Online.

“And since flies can transfer serious, contagious diseases like cholera, dysentery and typhoid, it is probably best if you avoid eating things that a fly lands on.”

What’s more, flies nearly always vomit on any food upon which they land.

Unable to chew, the insects have to throw up digestive enzymes onto the food to dissolve it and allow them to slurp it up.

Of course, it’s hard to avoid any fly ever landing on your food again, so what can you do?

The best tactic is simply to cut off the part the fly has touched and throw it away. But you should be fine to continue eating the rest. Phew.

Source: INDEPENDENT

India unprepared for dengue, Chikungunya finds analysis.

India and other countries in South Asia are unprepared to address emerging vector-borne viral infections such as dengue and chikungunya, an analysis released by Centre for Disease Dynamics, Economics & Policy (CDDEP) on Wednesday revealed.

After examining vulnerability to emerging and growing infectious disease threats and the capacity to respond to outbreaks, the analysis finds the level of preparedness is inadequate to protect public health across the region.

The main burden of vector-borne viral infections in the South Asia region are dengue and chikungunya, while zika virus is also likely to emerge. Of the 390 million dengue infections that are estimated to occur annually worldwide, over 70 per cent occur in South Asia, the analysis noted. The report cites that in India, almost 95 per cent of adults by the age 40 have been infected with dengue virus, while 41 per cent have been infected with chikungunya.

At the heels of the report, JP Nadda, Union Minister for Health and Family Welfare, held a high level meeting to review the preparedness of the Ministry and central government hospitals for prevention and control of dengue and chikungunya in the country.

South Asia’s battles against viral diseases
Countries in South Asia region — Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, and Sri Lanka, is home to a significant proportion of the global burden of infectious disease. Of the 390 million dengue infections that occur annually worldwide, over 70 per cent occur in South Asia

Longstanding battles
Tuberculosis, HIV, malaria, dengue, chikungunya

Emerging infectious diseases
Zika, ebola, MERS-CoV, avian influenza, neuroleptospirosis and leptospirosis, anthrax.

Source:DNA

Ant choosiness reveals they all have different personalities

The power to imagine a better world has helped transform human societies, and it may be doing the same to ant societies.

Individual ants have differences in behaviour – something almost akin to a personality – that affect colony decisions. And some ants are so different in their personal preferences that they may act as the imagination of the colony, driving it on to a better future.

Rock ants (Temnothorax albipennis), found in coastal areas of the UK, make their homes in crevices. If a nest is wrecked, or if scouts find better digs, it often makes sense to relocate.

But not just any crevice will do. When looking for a new home, ants have a high-maintenance list of requirements, says Thomas O’Shea-Wheller at the Ant Lab of the University of Bristol, UK. They seek low light levels, an entrance gap of 1 to 1.5 millimetres, a ceiling height of roughly 2 millimetres and an internal area of about 20 square centimetres. To test how individuals’ opinions of potential nests affect a group decision to relocate, O’Shea-Wheller’s team showed artificial nests that were excellent, good or poor to 160 individual ants from 10 colonies.

In general, the better the nest, the more time the ants spent in it laying down pheromones. These pheromones make other ants more likely to join them.

But the team found a lot of variability between the amount of time individuals spent in a nest of a certain quality. “Some ants are picky, others are more liberal and will accept almost anything,” says O’Shea-Wheller. “Much like humans, not everyone wants to live in a mansion.”

And some ants never seem happy, however nice a nest is. They live there, but seem restless, and are more likely to scout. It means they are always searching for new things. “They are the imagination of the colony,” says O’Shea-Wheller.

“The ability of the colony to find new nest sites depends on there being some wanting to search,” says Anna Dornhaus at the University of Arizona in Tucson. “It’s useful to the colony to have some ants that are fussy.”

The team modelled this behaviour and found that if the colony was choosing between two poor nests, the ants with more extreme behaviour – in this case the ones that would settle for almost anything – helped make the collective decision-making process faster and more flexible (Proceedings of the Royal Society B, DOI: 10.1098/rspb.2016.2237).

“This adds to the evidence that individuality is important,” says Nathalie Stroeymeyt at the University of Lausanne in Switzerland.

However, we still don’t know what’s behind this individuality. “We’d like to know what drives personality differences, what the evolutionary benefits are,” says Dornhaus. “At least this gives us a suggestion about why personality differences could be useful – and could benefit a colony.”

Source: News Scientist

India begins outdoor caged trials of genetically modified mosquitoes

India launched a project aimed at suppressing the local Aedes aegypti mosquito population by introducing genetically modified mosquitoes, according to two companies involved in the plan.

A similar project was approved last year in Florida on the heels of the Zika virus outbreak, which has been driven primarily by A. aegypti mosquitoes. Both projects involve so-called self-limiting male mosquitoes — brand name Friendly (Oxitec) — that are genetically modified to produce offspring that do not survive to maturity.

Five open field trials of the mosquitoes in Brazil, Panama and the Cayman Islands each led to a more than 90% reduction of the wild A. aegypti populations, according to a news release from the British company Oxitec and Gangabishan Bhikulal Investment and Trading Limited (GBIT), an Indian company. Open field trials are also planned for India, pending regulatory approval, the companies said.

For now, the India project was launched on Jan. 23 with outdoor caged trials in Dawalwadi. In these trials, the genetically modified mosquitoes are released into cages to mate with wild-type A. aegypti mosquitoes, Matthew Warren, spokesman for Oxitec, explained to Infectious Disease News. The results are then compared with cages where the mosquitoes were not released, Warren said.

In November, officials in Florida authorized a plan to use Oxitec’s modified mosquitoes in a field trial in Monroe County. The decision by the Florida Keys Mosquito Control District (FKMCD) came after residents, apparently reluctant about the method at first, voted to approve the idea.

An earlier survey showed that residents did not support the use of genetically modified mosquitoes as insect control, but the survey was conducted before the Zika outbreak became headline news and prior to an FDA report that said the mosquitoes would have no significant impact on human health, animal health or the environment.

Oxitec is currently deploying the mosquitoes in the Cayman Islands and Piracicaba, Brazil, but Warren said the trial in the Florida Keys is not yet underway.

“We are working with the FKMCD to identify a new site for the trial, and are gathering and submitting additional information to the FDA,” Warren said. “At this stage I don’t have a timeline, but we’re working to ensure that it is held in the most rigorous way possible and launched as promptly as the regulatory process will allow.”

While India is not among the 76 countries that have reported evidence of mosquito-borne Zika virus transmission since 2007, WHO has said that any country with a population of Aedes mosquitoes is at risk for transmission.

The primary aim of the project in India seems to be decreasing cases of dengue and chikungunya, which also can be spread by A. aegypti mosquitoes. According to estimates published in 2014, dengue infects an average of 5.8 million people each year in India at a cost of more than $1.1 billion. The country also has seen outbreaks of chikungunya, including some last year, according to the news release.

“Increasing cases of dengue and chikungunya have been reported in recent years,” Shirish Barwale, member of the board of directors at GBIT, said in the release. “Presently available methods have not been effective against these public health hazards. We are very optimistic that this pioneering technology from Oxitec will help us to control the mosquito responsible for spreading these diseases.” – by Gerard Gallagher

Source: Healio