13November2019

Andaman Chronicle

The Daily Diary of the Islands

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What could that crow have been saying to me?

Maneka Sanjay Gandhi

A few days ago I was on my early morning walk when a crow sitting on my gate started cawing to me. He was very agitated and I stood there trying to understand what he wanted. After two minutes I turned my back and started walking off. Immediately he flew at my head and pulled my hair. I turned around mystified and, because I didn’t know what else to do, I brought him a biscuit and water. He took a piece, honed it against the gate till it became a swallowable size, gave me one last disgusted look and flew off.

Crows and ants are my “thing”. So smart, so elegant, so sophisticated, so family minded, so disciplined, everything that humans should be and are not.  Every few months I write about them, and each time it is about a new facet of their intelligence which so outshines mine.

What is intelligence? Flying to a country several oceans away and landing in the same tree. Is that not uncommon intelligence? But we only measure intelligence by comparing it to things we do, like mimicking human speech, or adding two and two.

According to a study, published in the journal Behavioral Ecology and Sociobiology, crows have a sharp memory for human faces and can even remember which person is dangerous. Even if they meet the same person in a new place, they will recognize them. In an experiment, researchers in masks held the bodies of dead crows while laying out food for live ones. The crows rejected the food, alerted all the other crows and attacked the researchers. When the researchers returned weeks later wearing the same masks and without the dead crows, the birds continued to harass them. No food was picked up in the area for days after. When a crow encounters a mean human, it will teach other crows how to identify the human. Crows recognize cars, gaits and even timings, and they hold grudges.

Researchers captured 12 crows while wearing one face mask, and then housed them and fed them wearing another. After four weeks in captivity, the authors imaged the crow's brains and they found that, like humans, the birds have the ability to recognize people tied to their experiences. When shown the face of their captors, the threatening face "activated circuitry known in humans and other vertebrates to be related to emotion, motivation, and conditioned fear learning". In contrast, when they saw the caretaker face, it activated areas of the brain tied to associative learning, motivation, and hunger. In other words, much like humans, the crows recognize faces, and link them to emotions and memory.

How smart are they?  In 2018 a study done by Von Bayern, Danel, Auersperg, Mioduszewska and Kacelnik, Compound tool construction by New Caledonian crows, published by Nature Scientific Reports, used eight wild New Caledonian crows. In phase I, the birds were provided a long stick and a baited test box where food was within reach when using the stick, but not without it.  In phase II instead of a single long stick, they were given a hollow cylinder and a second, thinner cylinder that needed to be combined in order to generate a tool long enough to reach the food.  In phase III, the birds were given new combinable items. In the final phase, birds were presented a bait box that required the combination of more than two elements.

The birds passed the initial tool test, then combined the two elements to get the food and then used this knowledge to combine the new objects. In the final phase, one bird succeeded in making a tool that required more than two elements. These findings showed that New Caledonian crows are smarter than chimpanzees and gorillas in making compound tools. New research shows that New Caledonian crows carve thin strips of wood into skewers, and bend wires into hooks, and keep their favorite stick tools cached in “toolboxes” for further use!

In another study of Caledonian crows, the researchers set up a “vending machine” that could be operated by putting a piece of paper of a certain size into a slot, which would then release a treat. The crows quickly learned how to put the paper into the vending machine to get food. Then the crows were given paper of the wrong size for the vending machine. They had no reference of how big to make the paper, except from their memory. The crows made the paper into the right size and shape without any problem.

Aesop’s famous fable “The Crow and the Pitcher” tells of a thirsty crow who drops pebbles into a pitcher with water near the bottom, raising the water level high enough to let the bird drink. Scientists, trying to corroborate this story, found that crows given a similar problem dropped stones into a tube containing water, but not into a tube containing sand. They dropped dense objects into the water until the water came within reach. They did not select objects that would float in the water, nor did they select ones that were too large for the container. Human children gain this understanding, of volume displacement, around the ages of five to seven. Crows do indeed understand basic cause-effect relations.

A recent research collaboration, between Moscow State University and the University of Iowa, has discovered that crows are able to solve problems that require abstract thinking. For example, sameness and differentness are key abstract ideas, because two or more items of any kind—coins, cups, caps, or cars—can be the same as or different from one another. Analogical reasoning is considered to be the pinnacle of cognition and it only develops in humans between the ages of three and four.  The team trained crows to match items that were the same as each other (same colour, same shape, or same number). Next, the birds were tested to see if they could match objects that had the same relationship to each other. For example, a circle and a square would be analogous to red and green rather than to two oranges. The crows grasped the concept the first time, without any training in the concepts of "same and different."

Crows have relatively large brains for their body size, compared to other animals. Their brains have a higher neuronal density – the number of neurons per gram of brain than primates. So, they pack more processing power into their small brains.

I am still puzzled. What could that crow have been saying to me? 

To join the animal welfare movement contact This email address is being protected from spambots. You need JavaScript enabled to view it. , www.peopleforanimalsindia.org

  • Written by Denis Giles
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The Two Biggest Reasons for Climate Change

Maneka Sanjay Gandhi

Do people really understand climate change and global warming? A few days of unseasonal chill brings back the skeptic in everyone – if the earth is getting hotter then why we are experiencing low temperatures, is a common question.

That the earth is getting hotter is no longer a moot question. It is. But will the heat kill you? Yes. But not directly. You can still walk barefoot on the grass without getting your feet burnt!

You will get killed by the viruses, the insects, the tsunamis and cyclones, the jellyfish in the oceans, the lack of water.

The new kings of the earth are getting ready to take their thrones: mosquitoes.

Just as birds flock to warmer areas when winter settles in, wild creatures seek out weather that suits them. But a changing climate is moving that comfort zone for many animals, including disease-carrying mosquitoes.

Mosquitoes are the deadliest animals in the world. Their ability to carry and spread disease to humans causes millions of deaths every year. The worldwide incidence of dengue has risen 30-fold in the past 30 years, now infecting as many as 400 million people a year, with a quarter of them sick enough to be hospitalized, and more countries are reporting their first outbreaks of the disease. Zika, dengue, chikungunya, and yellow fever are all transmitted to humans by the Aedes aegypti  and Aedes albopictus mosquitoes, to name just two species. (Malaria spread by the Culex mosquito needs a whole article to itself).

And, global warming is letting them take over the world.

Published in Nature Microbiology in March 2019 , Scientists from Boston Children's Hospital, Oxford University, University of Washington, London School of Hygiene and Tropical Medicine and the Universite Libre de Bruxelles (Belgium) have combined all the available data  using climate, urbanization, migration and human travel and made prediction models  of the likely spread of two key disease-spreading mosquitoes -- Aedes aegypti and Aedes albopictus. The models forecast that by 2050, 49 percent of the world's population will live in places where these species are established, if greenhouse gas emissions continue at current rates. "We find evidence that if no action is taken to reduce the current rate at which the climate is warming, pockets of habitat will open up across many urban areas with vast amounts of individuals susceptible to infection,"

The team gathered data on the distributions of Aedes aegypti and Aedes albopictus over time, in more than 3,000 locations, starting from the 1970s. They mapped current locations which they considered suitable as mosquito habitats, then projected their suitability in 2020, 2050 and 2080, based on various climate models, projections of urban growth and other variables. They included human migration and travel patterns, using census data and mobile phone records.

Their findings : Aedes aegypti  has spread north at a relatively constant rate, about 150 miles per year. Aedes albopictus spread most quickly between 1990 and 1995. In Europe, Aedes albopictus has spread faster, advancing from 62 miles per year to 93 miles per year in the past five years.

Aedes aegypti is predicted to spread not just within its current tropical range, but also in new temperate areas in the U.S. and China, reaching as far north as Chicago and Shanghai, respectively, by 2050. Aedes albopictus, is forecast to spread widely throughout Europe over the next 30 years. It's also expected to arrive in northern U.S. and the highland regions of South America and East Africa. If climate change isn't curbed by 2050, the spread is predicted to be even greater. Zika virus started two years ago in South America and has already spread very fast, despite border control measures.

Climate change is the next great health threat, says Prof Paul Auerbach co-author of the book Enviromedics: The Impact of Climate Change on Human Health. As the globe warms, mosquitoes will roam beyond their current habitats, shifting the burden of diseases, like malaria, dengue, chikungunya and West Nile virus, to temperate and colder regions

Stanford biologist Erin Mordecai, and her colleagues from Stanford Medical School have also forecast how climate change will alter where mosquito species are most comfortable, and how quickly they spread disease. Economic development and cooler temperatures have largely kept mosquito-borne diseases out of wealthier Northern Hemisphere countries, but climate change will tip the scales in the other direction.

Their findings: malaria is most likely to spread at 25 degrees Celsius (78 degrees Fahrenheit) while the risk of Zika is highest at 29 degrees Celsius (84 degrees Fahrenheit). Carriers of dengue need the warmest climates, so will continue to plague hot regions such as sub-Saharan Africa. Mosquitoes that carry the West Nile virus, however, prefer a more temperate climate, so will migrate to cooler regions as the climate warms.

According to a study by Dr Soeren Metelmann et al of the University of Liverpool, almost all of England and Wales could be warm enough for the aedes species by the 2060s. Metelmann and colleagues created a model that combines knowledge of the life cycle of the mosquito with UK climate predictions from NASA for the period 2060–2069. So far tropical mosquitoes come with travellers to the UK in warm summer months and survive – and even breed – for a few weeks before disappearing in the winter. But his team’s research shows that in the near future such introductions could lead to the establishment of resident populations that survive the winter.

An international team, including Moritz Kraemer at the University of Oxford, has done an independent study that predicts that the mosquitos will spread throughout Europe over the next 30 years. Originally from East Asia, the insects have been spreading across Europe since the 1970s and are now found as far north as Germany and south-east England. In the last decade there have been outbreaks of chikungunya in Italy, showing that the spread of such mosquito-borne viruses within Europe is possible. By 2080 they predict that the mosquito will be in 197 countries worldwide, with 20 of those detecting its presence for the first time.

The mosquito seems to operate like a heat-driven missile of disease. Scientists say the hotter it gets, the better the mosquito is at transmitting a variety of dangerous illnesses. Mosquitoes live 10-12 days and that is how long it takes a virus to grow in its gut, making it infectious. Warmer air incubates the virus faster in the cold blooded mosquito, so the insect has more time to be infectious. Higher temperatures speed up larval development, increasing the number of adult populations, the autumnal development of the immature and consequently the increase of eggs over winter. Warmer temperatures make the mosquito hungrier, so it takes more blood meals and spreads more infection. Warmer temperatures also increase the mosquito population.

Zika, for instance, has been declared a global public health emergency after being linked to brain deformities in babies in South America. Zika outbreaks depend on temperature and drought. Recife, Brazil, the largest city in the Zika-struck region, saw its hottest September-October-November on record, about 1.2 degrees Celsius (2.2 degrees Fahrenheit) above normal, according to NASA data.

Aedes albopictus, the vector of a known vector of chikungunya virus, dengue virus and dirofilariasis, has undergone a dramatic global expansion facilitated by human activities, in particular the movement of used tyres and ‘lucky bamboo’ (single reason for its spread in Belgium and the Netherlands)– those horrible sticks they put in glasses of water and give to chief guests. It was first reported in Europe in 1979 in Albania. In 1985 it was first reported in Texas, USA . Now it is in 32 US states, including Hawaii. In Latin America it was first reported in Brazil in 1986. In Africa, it was first detected in 1990 in South Africa. It is now listed as one of the top 100 invasive species by the Invasive Species Specialist Group. This mosquito is already showing signs of adaptation to colder climates, which may result in disease transmission in new areas. It has already caused outbreaks of chikungunya in Italy and France and dengue in France and Croatia.

Its not just the spread of disease. Aedes albopictus is currently considered a serious biting nuisance for humans, where it is significantly reducing the quality of life. Adult females bite aggressively, usually during the day, both indoors and outdoors. Its prevalence has been linked to a reduction in children’s outdoor physical activity time, a factor contributing to childhood obesity.

Traditionally the aedes albopictus needs a mean winter temperature of 0 degrees C to permit egg overwintering, a mean annual temperature of 11 degrees C for adult survival and activity, and about 500 mm of annual rainfall. A summer temperature of 25‒30 degrees Celsius is required for optimum development. There are now reports of populations establishing in areas with lower mean temperatures (5‒28.5°C) and lower rainfall (290 mm annually).

Aedes albopictus can be the vector of at least 22 other viruses, including yellow fever virus, Rift Valley fever virus, Japanese encephalitis virus, West Nile virus. So, its spread is significant to human survival.

Can a mosquito carry more than one disease at the same time? Can someone get more than one disease from a single bite? Studies done in Gabon and India show that humans can be infected with chikungunya and dengue at the same time. Coinfection poses a challenge for accurate diagnosis, particularly when symptoms, such as fever and aches, can be similar.

Remember this every time you eat meat or allow a tree to be cut – the two biggest reasons for climate change. 

To join the animal welfare movement contact This email address is being protected from spambots. You need JavaScript enabled to view it. , www.peopleforanimalsindia.org

  • Written by Denis Giles
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Pets Prevent Allergies

Maneka Sanjay Gandhi

I meet so many mothers who won’t let their children walk barefoot in the house or the park, won’t let them touch snails, won’t let them grasp mud or go out in the hot rain of the monsoon, won’t let them near any animals and refuse to keep a pet because it might bring in bacteria. Their children wear socks throughout the year, have no idea what a plant is, apart from the cut flowers they see in vases at home.

And they are sicker than most children.

For decades paediatricians warned mothers that if they wanted their children allergy free they should keep animals out of the house.

By the early 2000s, a number of studies showed the opposite - that exposure to pets in the very early stages of life  confers protective benefits and prevents the development of allergic rhinitis, asthma and eczema. Of the nine studies analyzed in 2011, six detected lower levels of IgE antibodies and 15 to 21 percent less eczema in children who had been exposed to cats or dogs as soon they were born.

Allergies have been on the rise since the 20th century. Even in a country where nutrition levels are higher, like the USA, 8-10% of children have asthma, according to the Centers for Disease Control and Prevention. Asthma is a chronic lung disease that inflames and narrows the airways. It causes recurring bouts of wheezing, chest tightness, shortness of breath, and coughing. Conventional wisdom says that  reducing allergenic substances at home will help lessen asthma symptoms.

However the Urban Environment and Childhood Asthma (URECA) study, funded by the National Institute of Allergy and Infectious Diseases (NIAID), points in the opposite direction :  that exposure to certain allergens and bacteria early in life, before asthma develops, may protect children from asthma. Since 2005, URECA has tracked newborns who are at high risk for developing asthma, because at least one parent has asthma or allergies, for 7 years. Their findings were published in 2017, in the Journal of Allergy and Clinical Immunology.

Of the 442 children, 130 (29%) had asthma at age 7. The children who didn’t have it had , strangely enough, higher levels of cockroach, mouse, and cat/dog bacteria in the dust samples, collected from the children’s homes, during the first 3 years of life starting at 3 months.

“Our observations imply that exposure to a broad variety of indoor allergens, bacteria early in life may reduce the risk of developing asthma,” says URECA principal investigator. The microbes that pets carry into the home from outdoors, could mature baby’s developing immune system and train it to fend off assaults from allergens.

Researchers at Kuopio University Hospital in Finland, writing in the journal Pediatrics, say that babies who grow up in homes with a dog or a cat — have a lower risk of allergies than children who live pet-free. Their study found that living with household dust from homes with a dog, prevented infection with a common respiratory virus that is thought to increase the risk of childhood asthma.

The researchers followed 397 children, born in Finland between 2002 -5, and found that babies who grew up in homes with pets were 44% less likely to develop an ear infection and 29% less likely to receive antibiotics, compared with pet-free babies. Overall, babies who lived with a dog were 31% more likely to be healthy in their first year than babies without a dog; kids from homes with cats were 6% more likely to be healthy than those in cat-free families. The study found that children with pets were healthier overall. But this varies: the children who grew up with indoor dogs only, had more infections that than those whose dogs went out every day, suggesting that when animals are allowed to bring in more dirt and microbes from outdoors, it helps strengthen babies’ immune systems faster.

Research at the University of Alberta, published in the journal Microbiome, shows infants exposed to dirt and bacteria from furry family pets, especially dogs, showed much higher levels of two types of gut microbes associated with lower risks of obesity and allergic disease.

746 infants, in the Canadian Healthy Infant Longitudinal Development Study between 2009-2012,  also showed that those who grew up with dogs had lower rates of asthma and more diverse groups of microbes in their guts. The study also suggests having pets in the house could reduce the chances of a mother passing on a strep infection during birth, which can cause pneumonia in newborns.

Scientists at the University of San Diego Knight Lab, which is doing one of the largest studies on microbes in humans, has found that living with dogs provides the body protective benefit. Nearly a thousand species of microbes live inside the human gut and they play an important role in the health of the human by bolstering the immune system. Each species has a different impact and, without exposure to a diversity of bacteria, the body doesn’t learn how to differentiate between dangerous and harmless bacteria. This theory has emerged after more than a dozen studies showed that children born into families with significant farm animal exposure had fewer instances of asthma and allergies, compared with those that had no exposure to farm animals.

In a 2010 study, done in the University of California, researchers discovered that homes with dogs had a far greater abundance of bacteria than those with no pets. The scientists then researched on whether the dog microbe rich house dust would protect mice against allergens. It did. In 2016, the scientists went ahead to examine the faeces of 308 babies less than a year old. The results, published in Nature Medicine, showed that babies with the highest risk of developing allergies and asthma lacked dog exposure.

In the latest study, scientists from the University of Gothenburg, Sweden looked at another angle: if having more than one pet would increase the benefit.

They looked at data from two previous studies. One of them had tracked 1,029 children from infancy to age 8. 49% children, who had not had pets at home during their first 12 months of life, had allergies. This fell to 43 per cent in children who, as babies, had lived with one pet, and 24 per cent for children who had lived with three pets. Two of the children had lived with five pets – neither of them had allergies.

In another study, tracking 249 children from birth to 9 years of age, the rate of allergies was 48 per cent for children with no pets in their first year, 35 per cent for children with exposure to one pet, and 21 per cent for children who had lived with two or more pets.

This proves that more exposure to pets means more immunity Studies have found that children who grow up on a farm with livestock have a lower risk of allergies.

Can exposure to animals help pregnant  women’s growing babies ? A 2009 study in Europe showed that the umbilical cord blood in pregnant women with farm exposure had more active neonatal immune cells. This means that the microbes in the pregnant mother are doing something positive for the child.

We’ve known for years that dogs were good for our mental health. Now there is clear proof that those health benefits go even deeper. Pets prevent allergies. Exposure to an animal increases the baby’s immunity. The more cats or dogs you live with as an infant, the less your chances of getting asthma, hay fever and eczema, to name a few diseases. 

To join the animal welfare movement contact This email address is being protected from spambots. You need JavaScript enabled to view it. , www.peopleforanimalsindia.org

  • Written by Denis Giles
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