TB rates in children 'much higher than WHO estimates'

Researchers say 15 million children are living in homes with adults who have the disease

More than 650,000 children worldwide develop tuberculosis each year, research in the journal Lancet Global Health suggests.

The figure stands almost 25% higher than current predictions made by the World Health Organization.

Scientists say health officials may be missing an "enormous opportunity" to prevent the disease from spreading.

Malaria parasite 'gets down to the bone'

Mosquito with parasite sucking blood 

Parasites infected with malaria can hide inside the bone marrow and evade the body's defences, research confirms.

The discovery could lead to new drugs or vaccines to block transmission.

The research, published in Science Translational Medicine, fills a "key knowledge gap" in the biology of the disease, say scientists at Harvard.

Carried by mosquitoes, the parasite causes the most severe form of malaria, which leads to more than 500,000 deaths every year globally.

The study found that malaria-infected parasites could bury into bone marrow, where they escaped the immune system and caused disease.

The idea that they hide in the bone marrow while they mature has been around for decades.

But a team led by Prof Matthias Marti, of the Harvard School of Public Health, in Boston, pinpointed exactly where the parasites found sanctuaries in bone marrow by analysing tissue samples from autopsies.

"We have confirmed that the parasites that cause malaria can hide in the bone marrow," he told BBC News.

The discovery was "exciting" because it identified "a key knowledge gap in the biology of the parasite", he added.

The hope is that this may help scientists devise a way to target parasites hiding out in bone marrow with new drugs or vaccines. 

The most recent figures from the World Health Organization suggest malaria killed more than 600,000 people in 2012, with 90% of these deaths occurring in sub-Saharan Africa.

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Nakupa Habari: Cassini’s amazing space odyssey to Saturn Scientis...

Nakupa Habari: Cassini’s amazing space odyssey to Saturn Scientis...: Cassini’s amazing space odyssey to Saturn Scientists says Cassini is helping them undestand how our solar s...

Cassini’s amazing space odyssey to Saturn Scientists says Cassini is helping them undestand how our solar system developed.

Cassini’s amazing space odyssey to Saturn

Scientists says Cassini is helping them undestand how our solar system developed.

I like to call this 'Dressed in Purple,' ” says Essam Marouf, a Cassini radio science team member, of this 2005 image of Saturn's rings, captured by the spacecraft's radio wavelengths

 

Of the astronomically profound discoveries it’s made over a decade of circling, the startling hint this April of a new moon being formed in the rings of Saturn is merely the latest.

Indeed, the spacecraft Cassini — which inserted itself into orbit around the giant gas planet in July, 2004 — has transmitted imagery and sensory data back to Earth that has given us a new understanding of our bejewelled neighbour three doors down.

“It’s one of the most successful (space) missions probably ever,” says University of Toronto astrophysicist Hanno Rein, whose own work has been significantly informed by the tiny craft’s output.

“Fantastic … the stunning images, this is unprecedented. They’re an order of magnitude more exciting than anything we’ve seen before,” Rein says.

Rein is especially intrigued by the natal moon — tentatively named Peggy — that Cassini detected in Saturn’s outermost A Ring this spring.

Because he believes we could be witnessing in the icy satellite’s birth a small-scale version of the planetary formation that created our solar system billions of years ago.

“The kind of theories we develop for Saturn we then apply to other systems like the (ancient) disks (around the sun) in which planets formed,” Rein says.

“But for Saturn, we can observe how it forms in situ. It’s really exciting to see it in action.”

Yet the proto-moon simply joins in the metronomic output of discovery that Cassini has hurled back to Earth since reaching Saturn a decade ago — and during its seven-year, 3.5-billion kilometre journey to get there.

Jesse Rogerson, a PhD candidate in astrophysics at York University, has followed the Cassini project for years and says it’s been revolutionary for our understanding of the sixth planet.

The two NASA Voyager probes that flew past in the early 1980s were able to collect good data on the planet for only a few weeks each, Rogerson says.

“The only way to really learn about it is to have something sit there,” he says. “What Cassini has done for the Saturnian system, it’s like shining a light bulb in a darkened room.”

Speaking from NASA’s Jet Propulsion Laboratory in Pasadena, Calf., Cassini project manager Earl Maize says he’ll leave the superlatives to others.

“But … it’s been a wonderful ride,” Maize concedes. “The things that the project has discovered (it’s been) surprise after surprise over the last 10 years.”

Those surprises have fundamentally changed the scientific thinking about Saturn that began when Dutch astronomer Christian Huygens described the rings in 1655.

“In fact I would go even a little bit further and say some of the things Cassini has discovered have changed our view of our own solar system,” adds Linda Spilker, the project’s top scientist.

In particular, two moons in the Saturn system — which thanks in part to Cassini is now known to have at least 53 of them — have provided oceans of material for the craft’s camera’s and probes to explore.

The planet’s largest moon, Titan, which was also discovered by Huygens, has been obscured to astronomers by an orange haze for the 350 years since.

But beneath the fog, the Cassini mission revealed that Titan is among the most Earthlike worlds in the solar system, Spilker says.

The craft, which has made dozens of flybys of the moon, some within 100s of kilometres, also carried and released the European Huygens probe, which parachuted on to Titan’s surface in January, 2005.

Together the twined crafts have shown a moon with liquid methane seas, lakes and rivers and a vibrant, active atmosphere that have shaped its surface in very earthy ways. There’s even an occasional rain.

“We revealed that this really is … very analogous to Earth,” says Maize, who counts the exploration of Titan as the mission’s top achievement so far.

“We have rain, we have lakes, we have rivers, we have weather patterns … it’s absolutely fascinating.”

Continuing flybys will use Cassini’s radar and sensors to further map the moon’s topography, search for seasonal climate changes and attempt to confirm the presence of a huge ocean of water thought to lurk below Titan’s surface.

If Cassini showed Titan to be a topographical and atmospheric mirror of Earth, however, it showed the ice-moon Enceladus to be a tantalizing host for potential life.

Cassini pictures of the moon shocked scientists when they revealed massive geysers of salt water erupting from its southern pole, raising the possibility that Enceladus’ icy surface could be covering vast seas of water below.

With water being a prerequisite of life, tiny Enceladus — just 480 kilometres in diameter — leaped to the head of the solar system’s class of bodies where primitive organisms may one day be found.

“In Esceladus, with its icy jets, and Titan, with its methane lakes and liquid water ocean underneath, we’ve in a sense helped redefine the (solar system’s) habitable zone,” Spilker says.

“It (potential life sites) is no longer just sort of that Goldilocks zone, that place where the Earth orbits where you can have liquid water on the surface.”

In Saturn’s rings themselves, Cassini has revealed a credible analogy for the creation of the solar system’s planets, Spilker says.

Like the shifting clouds of ice, rock and dust that encircled our sun billions of years ago, Saturn’s rings are composed of materials, big and small, that are colliding and melding into larger bodies.

“We saw shadows of large mountain-sized particles that are accreting and accumulating in the rings and giving us ideas about maybe how planets formed in the solar system,” Spilker says.

“It’s just intriguing to think that maybe some of the tiny moons we see just outside the rings might have actually started in the rings themselves.”

It’s this moon-formation process that has most intrigued Rein, who believes that Saturn’s rings represent a current template for the solar system’s beginnings.

“The moons are so small that you can’t actually see the individual moons; there are maybe a few hundred that are maybe a kilometre in size,” he says. “But they create this small disturbance in the rings and because Cassini has such a good resolution you can actually see this perturbance.”

Following these ring disturbances should allow scientist to predict — applying the laws governing gravitational orbits — precisely where new moons will be when Cassini looks for them again, Rein says.

“But it turns out it’s not where (the laws) predicted it would be, it’s moved a bit. And it’s moving because there are strong interactions with the rings in which it’s embedded.”

This is the first time astronomers have seen objects in orbit change their course, Rein says.

And he says the alterations are likely caused by collisions between the tiny moons and even smaller bodies of ice and dirt within the rings. These herky-jerky pathways would be similar to the ones Earth and the other planets took during their formations.

Rein is currently running numerical simulations on the Cassini moonlet data to better understand these interrupted motions so as to better predict what may happen on a planetary scale.

“Really (however) it’s with Cassini just being there long enough to look for and discover these new things … that we’re rewriting the book not only about Saturn but about our solar system as well,” Spilker says.

In its decade at Saturn, the $3.3 billion (U.S.) Cassini mission has logged more than 3.2 billion kilometres in 206 orbits and generated more than 3,000 scientific papers back on Earth.

Some of its greatest orbital hits include:

• The discovery of seven new moons around the planet.
• The recording of a great northern storm that erupted in late 2010 and within months had grown to ring the planet in a swirling band of orange tumult. During the storm, which petered out soon after its head caught up with its tail, Cassini detected the largest temperature rise ever recorded on a planet and elements never seen before in Saturn’s atmosphere.
• The discovery of massive hurricanes at both poles of the planet.
• Photographing a shining Earth and its moon — while thousands of people on this planet waved up during the NASA’s “Earth Waves at Cassini” event — during a trip to the dark side of Saturn in July, 2013.
• The first full recording of the massive, hexagonal jet stream structure circling at Saturn’s northern pole.
• Rein speaks with awe about the ability of Cassini’s Earthbound handlers to position the craft for its orbital observations — manoeuvres that could give the term rocket science new lustre.

“The spacecraft has very little fuel … but they need to make very small changes to the spacecraft orbit with the little fuel they have,” he says. “And they’ve done a remarkable job with that.”

Instead of expending scarce fuel for orbit-altering thruster burns, Rein says, the probe’s remote pilots have plotted out close encounters with Saturn’s moons using their gravitational pull to sling the ship into desired positions above the planet.

“That they can do that is pretty amazing. It’s literally rocket science,” he says.

Its handlers employed similar gravitational strategies in guiding Cassini to its Saturn destination, using the pull of the sun and several of its other planets to manoeuvre and accelerate the craft during a journey of stupefying complexity.

The twined Cassini-Huygens package was launched from Florida’s Cape Canaveral Air Force Station atop a Titan IVB/Centaur rocket on Oct. 15, 1997.

And while the destination planet is a mere 1.5 billion miles from Earth on average, the craft had to travel more than twice that distance to get there.

The twinned Cassini-Huygens craft made two passes by Venus, where it added to already ample scientific probing of that planet.

It also made an Earth flyby on the way out to slingshot it in the right direction.

“Our biggest gravity assist (however) was Jupiter,” Maize says.

And it was at Jupiter that Cassini worked with the Galileo probe, already in orbit around that giant planet, to achieve a one-two science punch.

“While we were surfing inside and outside of the solar wind and Jupiter’s magnetic field, Galileo was deep inside,” Maize says.

“For the first time we were actually having two spacecrafts make simultaneous measurements of a giant planet’s magnetic field and that was just incredibly exciting.”

It also gave Cassini — named after Italian astronomer Giovanni Cassini — a chance to calibrate and test its 12-pack of instruments, two years before its Saturn encounter.

Later, by waking up Cassini’s propulsion system — which would insert it into Saturn’s orbit — at just the right time, the ground crew was able to take the first close-up readings and images of Phoebe, a Kuiper Belt planetoid that had been pulled into a Saturnal orbit.

If its beginnings were eventful, Cassini’s scheduled death a little more than three years hence promises to be breathtaking, Spilker says. The ship will be taken closer and closer to the planet until it’s finally plunged into its gaseous mass.

“Just imagine the great pictures we’re going to get of both the rings and the planet when we’re so close,” she says.

But before that grand finale, Maize says, he is certain of only one thing:

“We’re going to continue to be surprised.”

Ebola outbreak: West African states agree strategy.

workers, like these in Kenema, Sierra Leone, are taking blood samples to screen for the virus

Health ministers from 11 West African countries have adopted a common strategy to fight a deadly Ebola outbreak in the region.

At an emergency meeting in Ghana, ministers promised better collaboration to fight what has become the world's deadliest outbreak to date.

So far, 759 people have been infected with the virus in Guinea, Liberia and Sierra Leone and 467 of them have died.

The two-day meeting was called by the World Health Organization (WHO).

Under the new strategy, the WHO will open a sub-regional control centre in Guinea to co-ordinate technical support.

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India to provide four free vaccines, including rotavirus.

Diarrhoea from rotavirus kills nearly 80,000 children in India every year

India will provide four new vaccines free of cost as part of a programme to reduce child mortality, Prime Minister Narendra Modi has said.

They include one for rotavirus, which kills thousands of children a year.

The disease causes dehydration and severe diarrhoea. It spreads via contaminated hands and surfaces, and is common in Asia and Africa.

The move brings to 13 the number of free vaccines provided against life threatening diseases.

"The introduction of four new life-saving vaccines will play a key role in reducing childhood and infant mortality and morbidity in the country," Mr Modi said in a statement.

"Many of these vaccines are already available through private practitioners to those who can afford them. The government will now ensure that the benefits of vaccination reach all sections of society, regardless of social and economic status."

The four new vaccines will combat rotavirus, rubella, polio and Japanese encephalitis.

Diarrhoea caused by rotavirus kills nearly 80,000 children each year and results in up to a million hospital admissions in India, the statement said.

Regular outbreaks of encephalitis also kill hundreds of children every year. 

A new adult vaccine against Japanese encephalitis will now be introduced in the 179 worst-affected districts in nine states.

Though India was declared polio free in March, it will introduce an injectable polio vaccine to "provide long lasting protection to the population against the virus," the statement said.

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Scientists 'develop test for teen binge-drinking risk'.

Scientists claim to have developed a way of predicting which teenagers are likely to binge-drink.

A combination of 40 factors, including brain structure, personality and major life events, were used to produce the test.

It can predict, with 70% accuracy, which 14-year-olds are likely to binge-drink at 16.

But a simpler method would be needed to make the test practical because of the prohibitive costs of brain scans.

Studies have already looked for the differences between binge-drinking teenagers and those choosing a path of sobriety. 

However, they cannot tease out what makes someone more likely to consume copious amounts of alcohol from the changes caused by the drink.

'Bunch of little things'

An international group of scientists have now conducted the largest study of its type to find a way of predicting which teenagers will go on to binge-drink.

They looked at a huge array of variables, including family history, exposure to alcohol, neuroticism, extravagance, conscientiousness and other personality traits, a suite of genes, brain volume, how the brain responds to reward and many more.

Dr Robert Whelan, of University College Dublin, told the BBC: "There is no one really big thing. It's a bunch of little things adding up to give you this prediction.

"There are three main areas: brain activity and brain structure; personality, so seeking out new things to do increases the risk, whereas conscious tends to make you less likely to binge-drink; and then life events, such as a boyfriend or girlfriend, is highly predictive."  

However, he cautioned the test would have limited value in testing one individual as it was not accurate enough.

"It is very broad, but you could identify a group of people - say, take 1,000 kids and find the top 200 at a higher risk - to give them special intervention."

Dr Whelan added that it was important to identify those at risk of binge drinking because studies had shown alcohol has "neurotoxic effects which carry on into adulthood".

However, brain scans cost thousands of pounds per person. A simplified version of the test, focusing on relatively cheap personality and family history factors, is more likely to be used.

Hugh Perry, chairman of the Medical Research Council neurosciences and mental health board, said: "Addiction and substance misuse is a major medical, social and economic problem for the UK.

"The UK government spends more than £15bn annually in meeting the cost of drug-related social and economic harm."

He said further research could "lead to breakthroughs in this field and provide compelling evidence to inform public health policy and lay the groundwork for the design of interventions".

The findings will also be applied to other fields, including drug abuse and smoking.

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