Deet doesn’t work for Dengue mozzy

BBC news report that the mosquito repellent Deet is ineffective against the Aedes aegypti mosquito. According to the study in PLOS One, mosquitoes are first repelled by the chemical on an arm, but on a second visit they ignored the Deet and went for the arm.

The  Aedes aegypti mosquito is active during the day, so bed nets are ineffective. They need only a thimbleful of water to lay their eggs – a muddy puddle will do. So if mosquitoes evolve resistance to insect repellent, they are very difficult to get rid of.

Genetically modified mosquitoes could be the solution. A British company, Oxitec, has bred male mosquitoes who produce eggs that die after their larval stage. Tests are ongoing in Brazil.

New research centre shares NTD knowledge

Community workers distribute antibiotics in Ethiopia/Community Eye Health Flickr

In January last year, the world’s biggest drug companies pledged vast quantities of drugs to treat ten neglected tropical diseases. It was a moment for celebration; cheap, effective treatments would be available in regions of the world where health systems are often sketchy.

While, a year on, the programme appears to be progressing well, there are still questions remaining for the neglected tropical diseases. “Some of us were slightly concerned at the meeting a year ago,” says David Mabey, professor of communicable diseases at the London School of Hygiene and Tropical Medicine. Drug availability is a key hurdle in tackling NTD’s, but it is by no means the only one. Who do you give the drugs to? Where are the people who need treatment? And since people are often infected with more than one NTD, is there a good way to diagnose and treat them together

To help answer these questions, Imperial College, the Natural History Museum and the LSHTM have come together to establish the London Centre for Neglected Tropical Diseases. The “centre” is a virtual hub, intended to augment existing partnerships. Scientists from these institutes, all within three miles of each other, already work together on several projects. With initial funding from GlaxoSmithKline, this centre will encourage further collaboration.

The closer collaboration should allow institutes to share expertise. Many people have not just one neglected tropical disease, but several, and Mabey stresses the importance of developing integrated programmes to tackle the diseases together. Specialists in schistosomiasis from Imperial could have much to learn from trachoma specialists at LSHTM, and so on.

Battling blindness

Trachoma, an eye infection that is endemic across much of Africa and South-East Asia, epitomises some of the research questions facing researchers.  The Chlamydia trachomitis bacteria is spread by flies. The natural human response to painful eyes is to rub them, but the infected discharge also passes the disease. The consequences can be life-changing; repeated infection scars the eyelid, which can turn inwards. Eyelashes then scar the eye itself, leading to blindness if untreated.

Fortunately, there is a treatment, in the form of the antibiotic azithromycin. Surgery can alleviate symptoms, and improved sanitation stops the spread of the disease by reducing the transfer of infected eye-juice. The number of cases worldwide has dropped from 150 million in 1995 to 21 million.

But even after treatment, even once the active infection is gone from the eye, sometimes disease still persists in the follicles. We don’t know why, or whether this will lead to blindness.

Trachoma has been eliminated from several areas, but how long should surveillance continue, and what is the best way to do so? Hopefully this question will become relevant to more and more NTDs. Monitoring infection levels can be expensive and difficult. Simon Brooker, deputy director of the new centre, has written a blog about mapping the spread of diseases within countries using mobile phones and GPS. In Africa, technology development has skipped a generation, and mobile and satellite technology rules over landlines and broadband cables. Trachoma is just one disease using mobile technology to ensure data is accurate, and the techniques can be developed and shared for all neglected tropical diseases.

The ultimate aim of research into NTDs is to make treatment cheaper and more effective.. “These diseases are attracting the attention they deserve,” says Mabey. “Integrated control of NTDs will saves money,” says Mabey. But drug companies do not want to donate drugs forever; eradicating and eliminating disease requires the collaboration encouraged by the London Centre for NTDs.

Guinea worm cases decreasing, but war threatens campaign

Guinea worm

I’m a bit late to the party with this one (I’ll go stand in the blogger naughty corner) but last week the Carter Center announced the number of cases of Guinea worm in 2012. And there’s been a marked drop from the previous year. There were only 542 cases of the parasite in 2012, compared to 1058 in 2011 and 3.5 million in 1986. But the deteriorating political situation in Mali is threatening the eradication effort. Continue reading

One year on…

Exactly twelve months ago on a chilly January morning in central London, a group of pharmaceutical companies and charities, led by Bill Gates, announced a new strategy to combat ten neglected tropical diseases.

The London Declaration promised to control, eliminate, and in the case of Guinea Worm, completely eradicate the diseases, through a program of education, improved sanitation, and billions of dollars of free drugs. The world’s biggest drugs manufacturers signed up, as did the UK and US government.

So one year on, how are they doing? Continue reading

Cows provide clues to worm and tuberculosis interactions

I’ve written a piece for Nature News this week on how liver fluke could be preventing diagnosis of bovine tuberculosis (bTB) in cattle in the UK. The research I’m reporting on looks specifically at a fluke (aka trematode worm) called Fasciola hepatica, but there are lots of other flukes around – including schistosomiasis, which affects 230 million people a year. Continue reading

ECCMID 2012: Professor Jonathan Cohen

The European Congress on Clinical Microbiology and Infectious Diseases (ECCMID) is in London this weekend, running from Saturday until Tuesday. One in seven people are there, so follow our twitter feed for live updates on what’s going on.

ECCMID is vast – there are 10,000 attendees – and covers areas from insect bites to complex immunology. I managed to nab this year’s President, Professor Jonathan Cohen, to find out more about this year’s Congress and the largest public health event of the year, the London Olympics and Paralympics. We’d just listened to the 2011 Nobel Laureate in Medicine, Professor Jules A. Hoffman, give a keynote address on phylogenetics. Continue reading

What pictures are good pictures?

Buruli ulcer has horrifying effects. The Mycobacterium ulcerans pathogen eats away skin and occasionally bone, causing huge, bloody lesions on the arms and legs.

Lymphatic filariasis is equally shocking, though less stomach churning. In women, long-term infection leaves sufferers legs swollen with fluid; in men, fluid often gathers in the testes, swelling them to many times their normal size. Continue reading