Malaria hope: Bacteria that make mosquitoes resistant
Researchers have found a strain of
bacteria that can infect mosquitoes and make them resistant to the malaria
parasite.
The study, in the journal Science, showed the parasite struggled to survive in infected mosquitoes.
Malaria is spread between people by the insects so it is hoped that giving mosquitoes malaria immunity could reduce human cases.
Experts said this was a first, distant prospect for malaria control.
Malaria is a major global disease. The World Health Organization estimates that 220 million people are infected annually and 660,000 die.
Challenge
The study at Michigan State University in the US looked at the Wolbachia bacterium, which commonly infects insects.
It passes only from females to their offspring. In some insects the bug is exceptionally good at manipulating insects to boost the number of females for its own ends.
Wolbachia kills male embryos in some butterflies and ladybirds. In other situations, it can produce males that can breed only with infected females, and even allows some female wasps to give birth without mating.
Malaria-carrying Anopheles mosquitoes are not naturally plagued by Wolbachia, yet laboratory studies have shown that temporary infection made the insects immune to the malaria parasite.
The challenge was to turn a temporary infection into one that would be passed on. The research team found a strain of Wolbachia that could persist in one species of mosquito, Anopheles stephensi, for the entire length of the study - 34 generations.
Malaria parasites found it difficult to cope in these mosquitoes, with parasite levels fourfold lower than in uninfected bugs.
Research in Australia has shown that a different strain of Wolbachia can prevent the spread of dengue fever by mosquitoes. That research is more advanced and has been shown to work in large trials in the wild.
Dr Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases in the US, said this study was a proof of concept that the same could be done for malaria.
"If you can get it to survive and proliferate in the environment of mosquitoes in malaria-stricken areas, this could conceivably have an important impact on the control of malaria.
"I think the potential for this is very important. The implementation will be the challenge."
'Struggle to spread'
Commenting on the study, Prof David Conway, of the London School of Hygiene & Tropical Medicine, said: "It is interesting and is the first report of Wolbachia clearly replicating, but a number of things took away the punch."
He said the infected females produced fewer eggs than uninfected females, which meant the infection would struggle to spread in the real world.
Also he cautioned that it was in just one species, Anopheles stephensi, which carries malaria in the Middle East and South Asia. Anopheles gambiae, in Africa, is a bigger problem.
One of the researchers, Dr Zhiyong Xi, told the BBC: "We have done only one strain. If we target Anopheles gambiae we would need to apply the same technique again."
He added that if it could be shown to work then "the Wolbachia tool can complement currently available tools", such as mosquito nets and
Dhaka building collapse: Woman pulled alive from rubble
The BBC's Akbar Hossain: "People here are extremely surprised."
Photo courtesy Shariful Islam
A woman has been pulled alive from
the ruins of an eight-storey building that collapsed in a suburb of Bangladesh's
capital, Dhaka, 17 days ago.
Rescuers said the woman, named Reshma, was found in the remains of the second floor of the Rana Plaza after they heard her crying: "Please save me."
She has been taken to hospital, but is not thought to have serious injuries.
More than 1,000 are now confirmed to have died, most of them women working in clothes factories.
The authorities said 2,437 people had been rescued, of whom about 1,000 had suffered serious injuries.
Reshma: "I kept banging whatever I could with my legs but
no-one could hear me"
Dozens lost limbs as they were cut free from the wreckage.
The accident is one of the deadliest industrial disasters in history.
Crews using heavy machinery have begun removing rubble from the worst-damaged areas, and are expecting to find more bodies.
Brig-Gen Siddiqul Alam said rescuers had found a huge number of bodies under staircases.
"When the building started to collapse, workers thought they would be safe under the staircases. Each time we moved a slab of concrete, we found a stack of bodies," he said.
“Start Quote
Over two weeks after collapse, there is still no agreement on exactly how many workers and staff were present in the building”
End Quote Sabir Mustafa BBC
Bengali service
'I'm still here'
Soldiers were reported to have been preparing to break
through a large concrete slab at about 15:15 local time (10:15 GMT) on Friday
when the woman was discovered.
The worker who first discovered her told the BBC Bengali service: "I was cutting iron rods when I suddenly found a silvery stick just moving from a hole.
"I looked closer and heard someone calling 'Please save me'. I immediately called over soldiers and firefighters."
Officers ordered workers operating heavy machinery to stop, and rescuers used video and audio detection equipment to locate her exact position.
Crews saw a woman waving her hand, and she shouted "I'm still here" and told rescuers her name was Reshma.
Within minutes, hundreds of soldiers and firefighters rushed to the scene to help clear the rubble, says the BBC's Akbar Hossain in Dhaka.
The woman said that she was not badly hurt, and she was given water and biscuits while handsaws and drilling equipment were brought in to cut through iron rods and debris.
Rubble survivor records
- Naqsha Bibi - buried for 63 days in what had been her kitchen after 2005 Pakistan quake; survived on rotten food and water
- Evans Monsignac - trapped for 27 days in the rubble after 2010 Haiti tremor; stayed alive by drinking sewage water
- Park Seung Hyun - pulled from the wreckage of a supermarket in South Korea in 1995, 16 days after it collapsed; drank rainwater
- Pedrito Dy - spent 14 days in the ruins of a hotel after the 1990 Philippines tremor; drank water and urine
Rescuers worked for 40 minutes before finally pulling
her from the rubble, amid cheers from the crowd.
She was taken to an ambulance and then rushed to the nearby Combined Military Hospital for evaluation and treatment.
She later told local TV from her hospital bed that she never dreamt she would see daylight again.
"I heard voices of the rescue workers for several days. I kept hitting the wreckage with sticks and rods to attract their attention. No-one heard me," she said.
"I ate dried food for 15 days. The last two days I had nothing but water."
Her sister, Fatima, said the family had given up hope.
"When I first saw her on the TV, and when I realised that she was still alive, I was ecstatic," she told the BBC.
Prime Minister Sheikh Hasina, whose government has been criticised for lax oversight of the clothing industry, spoke to the woman on the telephone.
Ms Hasina was reportedly flying to the hospital by helicopter to meet her.
Rana Plaza had housed several factories that made clothes for companies including Western retailers.
A preliminary government report suggested the collapse was been triggered when electricity generators switched on during a blackout.
At least nine people have been arrested over the accident, including the owner of the building and several factory bosses.
Flu in pregnancy 'may raise bipolar risk for baby'
Flu during pregnancy may increase the
risk of the unborn child developing bipolar disorder later in life, research
suggests.
A study of 814 expectant women, published in JAMA Psychiatry, showed that infection made bipolar four times more likely.
The overall risk remained low, but it echoes similar findings linking flu and schizophrenia.
Experts said the risks were small and women should not worry.
Bipolar leads to intense mood swings, which can last months, ranging from depression and despair to manic feelings of joy, overactivity and loss of inhibitions.
Researchers at the Columbia University Medical Center identified a link between the condition, often diagnosed during late teens and twenties, and experiences in the womb.
In their study looking at people born in the early 1960s, bipolar disorder was nearly four times as common in people whose mothers caught flu during pregnancy.
The condition affects about one in 100 people. The lead researcher, Prof Alan Brown, estimated that influenza infection during pregnancy could lead to a 3-4% chance of bipolar disorder in the resulting children.
However, in the vast majority of cases of bipolar disorder there would no history of flu.
Seasonal vaccination
So in the list of things pregnant women have to worry about, how high should it rank?
"I wouldn't say high," Prof Alan Brown told the BBC.
"The chances are still quite small. I don't think it should raise alarms for mothers."
He said seasonal flu vaccination, which is advised for pregnant women in many countries, would reduce the chances of catching flu.
Similar studies have shown a link between flu and schizophrenia
How flu could affect the foetal brain has not been completely explained.
Influenza is not thought to directly affect the foetus, but the mother's immune response to the virus could affect development.
Dr Fiona Gaughran, lead consultant psychiatrist at South London and Maudsley NHS Foundation Trust, said: "This highly regarded group of researchers has reported similar links between schizophrenia and various maternal infections.
"If future work confirms the link reported here, policymakers may need to consider implications for flu prevention pre-pregnancy, but mothers need not be worried.
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