Malaria drugs' complete failure tracked

Scientists have developed a way to track the spread of a dangerous form of malaria that cannot be treated with the main therapy.

Doctors in Cambodia reported the complete failure of artemisinin and piperaquine - the key drugs taken to kill malaria - this year.

The discovery of resistance markers, reported in the Lancet, will allow scientists to track the threat.

Experts said the study was a big step forward.

Artemisinin resistance has been known about for years, but a recent rise in resistance to piperaquine as well means the main malaria treatment, taking both together, is starting to fail.

International groups of researchers analysed the DNA from hundreds of malaria parasites to find out how they learned to shrug off piperaquine.

They uncovered genetic signatures unique to the parasites that were drug-resistant.

Dr Roberto Amato, from the Wellcome Trust Sanger Institute, told the BBC News website: "Resistance is quite widespread, there has been almost complete failure in one province in the western part of the country, and it is spreading quiet fast in the north of the country.

"The problem with complete failure is this might accelerate the spread of drug-resistance to other countries and ultimately to Africa."

Resistance to the drugs would be catastrophic in Africa, where 88% of all malaria cases happen.

Get ahead

Dr Amato added: "The good news is we're starting to get clues on which treatment to use."

Curiously, these resistant parasites appear to still be susceptible to an older drug - mefloquine.

One theory is that the malaria parasites cannot resist both mefloquine and piperaquine, so doctors may be able to rotate which drugs are used.

And for Dr Amato, the long-term aim is to be able to keep one step ahead of the parasite.

He said: "They evolve every single day to escape the human immune system and the insect immune system - they're extremely good at it - and we need to understand that.

"Understanding how and in which direction is crucial, if we understand the process from most basic level then we could at some point predict the direction it is going to evolve."

Prof David Conway, from the London School of Hygiene and Tropical Medicine, said: "These studies are a big step forward in our understanding.

"This evolving parasite resistance is a major threat for malaria control internationally."

Worried well 'might boost heart risk'

Being one of the "worried well" might actually increase heart-disease risk, a study has suggested.

Norwegian researchers looked at health anxiety levels in 7,000 people who were followed for at least a decade.

The BMJ Open paper suggests that, while general anxiety is already recognised as a risk, health anxiety might also be an issue.

Heart experts said anyone who felt they were experiencing 'health anxiety' should speak to their doctor.

Health anxiety describes when people have a "persistent preoccupation" with having or acquiring a serious illness, and seeking prompt medical advice, without any symptoms of an actual disease.

Participants in this study were taking part in the Norwegian Hordaland Health Study (HUSK).

Dilemma

All were born between 1953 and 1957.

They completed questionnaires about health, lifestyle, and education and had blood tests, and their weight, height, and blood pressure measured regularly between 1997 and 1999.

They used a recognised scale called the Whiteley Index to assess anxiety levels.

The researchers also used national data to track hospital treatment and deaths in the group up to 2009.

And of the 7,000, 234 (3.3%) had a heart attack or bout of acute angina during the monitoring period.

Even after known risk factors were taken into account, the proportion of those succumbing to heart disease (just over 6%) was more than twice as high among the 710 considered to have health anxiety.

And the higher their anxiety score, the greater the risk of developing heart disease.

'Natural to worry'

Writing in BMJ Open, the researchers, led by Dr Line Iden Berge, said: "[Our research] further indicates that characteristic behaviour among persons with health anxiety, such as monitoring and frequent check-ups of symptoms, does not reduce the risk of [coronary heart disease] events.

"These findings illustrate the dilemma for clinicians between reassuring the patient that current physical symptoms of anxiety do not represent heart disease, contrasted against the emerging knowledge on how anxiety, over time, may be causally associated with increased risk of [coronary artery disease]."

Emily Reeve, a senior cardiac nurse at the British Heart Foundation, said: "It's natural for people to worry if they feel they might be unwell.

"But anxiety and stress can trigger unhealthy habits, such as smoking or eating badly, which put you at greater risk of heart disease.

"While we don't know if the 'worried well' are directly putting themselves at risk of a heart attack, it's clear that reducing unnecessary anxiety can have health benefits.

"If you are experiencing health anxiety, speak to your doctor."

Zika outbreak: The mosquito menace

This blood sucker might not be your best friend, but it loves you.

The mosquito, Aedes aegypti, is causing widespread fear in Brazil where it is spreading the Zika virus that has been linked to thousands of babies being born with birth defects.

So what do we know about it?

Grey line

It loves our cities

This is not some jungle-dwelling insect that rarely comes into contact with people.

It is one of those animals, like cockroaches, pigeons and urban foxes, that thrives in built-up areas.

It does not need natural water sources to breed as it can lay eggs in the small and plentiful pools of stagnant water, such as gutters or flower pots, found in cities .

Cities like Singapore have big problems with the mosquito.

Prof Uriel Kitron, from Emory University, said: "Aegypti is really adapted well for urban areas.

"It is becoming more and more of an urbanised world and aegypti thrives - Brazil is an extreme example going from 20% to 80% urban in 70 years."

There's also plenty of food - us.

Zika is currently getting all the attention, but Aedes aegypti has long been known as the yellow fever mosquito.

Yellow fever is a viral disease that can cause jaundice, bleeding and multiple organ failure in some cases.

And 390 million people are infected with the dengue virus each year, largely as a result of bites from Aedes aegypti.

Chikungunya, another virus causing alarm as it expands around the world, is also spread by the insects.

They do it by biting someone who is infected and then biting someone else.

Stop junk food ads on kids' apps - WHO

Children need to be protected from pervasive junk food adverts in apps, social media and video blogs, the World Health Organization says.

Its report warns parents are often unaware of the sheer volume of such adverts as they are precisely targeting children.

The WHO also criticised governments for failing to keep up with a revolution in the way people consume media.

Children's doctors said strict measures were needed to stop childhood obesity.

The report attacked the way some video bloggers - vloggers - get paid by junk food retailers to promote their food.

It quotes a US analysis that suggests vloggers are now more influential at promoting brands than film or TV because of perceived authenticity.

It also raised concern about the way fast food chains encourage kids through their doors by making restaurants important locations in augmented reality games like Pokemon Go.

And said data on children - their age, location, likes and preferences - were being collected to target them with junk food adverts.

Dr Joao Breda, the WHO programme manager for nutrition, physical activity and obesity, told the BBC News website: "It is going digital very strongly and we know that existing models of regulation have holes and gaps that don't cover the needs of our children.

"We think it's huge, but parents don't know - sometimes they don't realise their children are being exposed.

"You could argue that is it more dangerous [than traditional media like TV]."

Some countries such as the UK have introduced rules to protect children from junk-food advertising such as bans during children's television, however, the report said regulation had "failed to keep up with the pace and scope of change in the media".

On Thursday, figures in England showed nearly one-in-five children were obese when they left primary school.

"With the obesogenic environment they are living in today, it really isn't a surprise," said Prof Russell Viner, from the UK's Royal College of Paediatrics and Child Health.

He added: "It is reprehensible that children are targeted online, through billboard advertising and on television as they watch their favourite shows."

Prof Viner said there needed to be "strict measures put in place to protect" children and that governments needed to act urgently to prevent "marketers cynically targeting children online, on our streets and on television".

Dr Alison Tedstone, chief nutritionist at Public Health England, said: "Our evidence review shows that all forms of advertising and marketing - including the use of characters, advergames and digital marketing - affect the balance of children's diets."

The organisation is currently reviewing what foods and drinks can be advertised to children.