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Recording the history of malaria in Africa

The largest repository of any parasitic disease in the world - a collection of malaria survey data in Africa – has been unveiled by researchers at the Kenya Medical Research Institute and the Wellcome Trust. The collection covers more than 50,000 surveys spanning 115 years since 1900, each documented by date, geolocation, number of people, and the proportion positive for Plasmodium falciparum infection.

The researchers analysed the data to estimate malaria infection prevalence for each of 520 administrative units of Sub-Saharan African Countries and Madagascar for 16 time periods since 1900 through to 2010-2015.

The biggest historical drops in malaria followed the Second World War with the discovery of DDT and chloroquine, and later in 2005 with the rolling out of insecticide treated bed nets and new drugs to treat malaria.

Malaria prevalence was low during the late 1960s, through the 1970s and early 1980s. This was a period when, despite the international community abandoning investment in malaria control in Africa, chloroquine use was widespread with repeated dosing available to the general population. Together with drought across the Sahel, this produced the perfect lull in malaria transmission.

‘People often focus on recent history in tracking malaria in Africa, to inform donors and control programmes on recent actions,’ says the study’s lead author Professor Bob Snow of Oxford’s Centre for Tropical Medicine and Global health. ‘The longer history of malaria in Africa allows us to put into context the recent decline.’

Chloroquine resistance expanded across Africa in the 1980s, and in the late 1990s unprecedented rainfall led to flooding and major malaria epidemics. Ministries of Health across the continent woke up to the perfect storm without any significant mosquito vector control in place. Malaria prevalence returned to the levels seen before the Second World War.

It took a further five years for the international community to provide free insecticide treated bed nets and effective malaria treatments. The financial response by the Global Fund and the technical revisions to policy by the World Health Organisation after 2005 led to one of the largest drops in malaria infection prevalence witnessed since 1900.

Co-author, Abdisalan Noor of the Kenya Medical Research Institute/Wellcome Trust Research Programme (KEMRI-WTRP), adds: ‘Shown in context, the cycles and trend over the past 115 years are inconsistent with explanations in terms of climate or deliberate intervention alone. The role of socio-economic development, for example, remains poorly understood.’

The current prevalence of infection, 24%, is at its lowest in 115 years but gains have stalled since 2010 and 240 million infected individuals remains a substantial burden. Little has changed in the high transmission belt across West and Central Africa. Emerging insecticide and drug resistance remain a threat, along with growing international ambivalence to funding control.

‘The history of malaria risk in Africa is complex, there have been perfect lulls when drugs worked and droughts prevented mosquito’s transmission infection; there have been perfect storms when drugs stopped working and flooding affected large parts of Africa,’ adds Snow. ‘It has been a history of long term cycles and predicting the future of malaria in Africa based on climate or intervention coverage alone is difficult.’

Clouded leopard

A new study led by Oxford scientists has produced the first robust estimate of the number of Sunda clouded leopards remaining in the state of Sabah, Malaysian Borneo.

The research also explores how changes to Sabah's forest landscape may be affecting these threatened wild cats.

The study, led by researchers from Oxford’s Wildlife Conservation Research Unit (WildCRU) in collaboration with partners from the Universiti Malaysia Sabah, Danau Girang Field Centre (DGFC), Sabah Wildlife Department and Panthera, provides the first evidence that the population density of the Sunda clouded leopard is negatively affected by hunting pressure and forest fragmentation.

The research, published in the journal Oryx, also had some positive news, showing that clouded leopards can persist after a forest is logged and that their numbers may increase over time as the forest begins to recover.

Dr Andrew Hearn from WildCRU, first author of the paper, said: 'For six years, we conducted intensive camera-trap surveys of eight protected areas in Sabah. We used the cloud-shaped markings on the coat of the animal and morphology to identify and sex individual animals and used sophisticated statistical methods to estimate their population density in different forest areas across Sabah. We also analysed our camera-trap data to provide an estimate of poaching pressure for each study area.

'We found evidence of poaching activity in all forest areas, with the lowest detection rates being in Danum and the highest in Kinabatangan. We finally estimated the size of the population of the Sunda clouded leopard to be around 750 individuals in Sabah.'

Clouded leopardClouded leopard (image credit: DGFC)

DGFC director Dr Benoit Goossens, a co-author of the study, said he hoped the results of the study, together with the action plan for the Sunda clouded leopard being launched next year, will help to manage the species in Sabah's forests. He added: 'The fact that selectively logged forests provide an important resource for Sunda clouded leopards suggests that appropriate management of these commercial forests could further enhance their conservation value. But the overriding priority for our wildlife managers is to reduce poaching pressure, both on these felids and their prey, by reducing access to the forest interior along logging roads and by increasing enforcement patrols at strategic areas.'

Professor David Macdonald, Director of WildCRU, said: 'Clouded leopards are stunningly beautiful, and as denizens of some of the most threatened forests in the world they have the potential to be iconic symbols for conservation: our findings are a big step on that road.'

Luke Hunter, President and Chief Conservation Officer at Panthera, said: 'The clouded leopard is the top cat of Sabah, playing a similar role as tigers or leopards in continental Asia. Sadly, just as for tigers and leopards elsewhere, clouded leopards are targeted by poachers. Our work emphasises yet again how saving big cats and their prey relies on strong protection and robust anti-poaching measures.'

The research was primarily funded by the Darwin Initiative, the Recanati-Kaplan Foundation, the Robertson Foundation and the Sime Darby Foundation.

Image credit: Shutterstock

What do scientists, philosophers and religious leaders all have in common? The answer may surprise you, but collectively at least, they have the power to fight climate change. 

At a recent special event during the 2017 European Capacity Building Initiative (ecbi) Oxford Seminar, leading voices from these three fields came together to discuss one of society’s most challenging questions: ‘what can we do to support the fight against global warming in the current political climate?’

Held at the University of Oxford, Museum of Natural History, the ‘We Meet Again!’ event was reminiscent of the renowned ‘Oxford Evolution Debate’ of 1860, and was intentionally named to draw comparison to that historic event.

Key speakers from the day share highlights and their thoughts on on how the problem can be best managed:

The Rt. Revd. Dr. Steven Croft, Bishop of Oxford, on the important position that faith-based communities can play in preventing climate change:

There is a myth that religious groups do not care about or believe in climate change - but the reality could not be further from the truth. Climate deniers exist in all walks of life and religious influencers such as myself, put a lot of effort into both educating their sects about the reality of environmental change and encouraging those involved in creating solutions to consider these communities.

It is vital that all involved in climate change negotiations understand and take seriously the different faith-based communities in the world, who are natural allies in carbon emission reduction and a more sustainable future.

Faith communities know how to take action for change and how to mobilise others to achieve common goals.

These groups are places where small groups of thoughtful and committed citizens are found. They have significant influence, a natural compassion for the earth and a sense of being part of a global community. They are not perfect, or uniform. But they are communities of hope whose values lead us to work for change, not against the findings of science, but in tandem, to bring about a more sustainable world.

Professor Sir Brian Hoskins, Director of the Grantham Institute for Climate Change at Imperial College London, discusses why scientists must not be intimidated:

The ferocity of Hurricane Harvey and Irma has many in the media and elsewhere saying that this is because of climate change, while others are saying they are nothing to do with climate change. Most scientists tend to be sitting somewhere in the middle, trying to stay true to their scientific, observational, evidence, theory and their projections for the future. Their message is ‘well neither of you are quite right’, instead giving a more nuanced message; that’s exactly what we have to do - and what we have to keep doing.

As scientists, we must continue to search for evidence-based answers and share the results of our work with a wide, diverse audience - not just our peers, opinion formers or politicians but ordinary people, without either exaggeration or understatement. We have to recognise that how these messages are received is directly influenced by the values and beliefs of the audience. For example, when confronted, some climate deniers approach the subject from a vested personal interest or political creed. Often the science is secondary to them and muddies the waters of what they want to believe.

As scientists, we must recognise that we are also influenced by our values and beliefs. We need to find common ground and a starting point for conversation. Then we must position the best science and research-led evidence at the fore-front of this climate change conversation.

Professor Benito Müller, Director of the ecbi, and a member of the Oxford University Philosophy Faculty, on what philosophers can do:

Philosophers have played a role in shaping popular opinion and challenging the status quo since time immemorial. John Alexander Smith, Waynflete Professor of Moral and Metaphysical Philosophy at Oxford University, opened his 1914 undergraduate lectures with the following caveat: ‘Apart from the few who go on to become teachers or dons, nothing that you will learn in the course of your studies will be of the slightest possible use to you in life, save only this, that if you work hard and intelligently you should be able to detect when a man is talking rot..’

Philosophers have an important role to play in separating truth from nonsense. 'Alternative facts' only work if one removes objective truth from what we mean by 'fact'. Yet, "2+2 = 5" is not an 'alternative fact' of mathematics. It is simply wrong, and anyone claiming the contrary is, to quote Professor Smith: 'talking rot'.

And the same applies to climate science, where assertions are objectively true or false, and not mere subjective opinions without objectively falsifiable content. To reply: “this is your opinion” when challenged about a statement in this context, and to leave it at that, is simply not good enough.

Stressing this unequivocally is one thing philosophers can do to support the fight against global warming in today’s fragile political climate. Academic thinkers and philosophers have a duty to stand up for critical thought and the truth, to counter the current tide of ‘alternative facts’ and ‘post-truth’ politics.

Professor Paul Smith, Director of the Natural History Museum and an esteemed Arctic Scientist, concludes:

As an Arctic scientist I have been travelling to the Northern Hemisphere for more than thirty years, and have seen polar melting with my own eyes. I can say with confidence that climate change is not a myth. It is very real. It is happening and it shows no signs of slowing down.

In today’s society, Arctic research is more valuable than ever. The reasons for this will vary from field to field, but climate change is currently at its most exaggerated in polar areas. For glaciologists and those interested in climate change, the Poles are therefore a rich environment to witness climate change first hand. Where as, for geologists and people in my discipline, the exposed rock is the real attraction. In the Arctic we are not hindered by vegetation. There are of course areas covered with glacial deposits, but other than that, there is just the expanse of exposed rock that you just don’t get at lower latitudes. The far north has perfect “outcrop”, as we call it.

We live in a time where the value of science is constantly being questioned and undercut, it has never been more important for us as scientists to perform our jobs well, deliver accurate research and clearly communicating the findings. The consequences of not doing so are catastrophic.

Quantum rainbows

What are quantum rainbows?

Stuart Gillespie | 5 Oct 2017

In the latest animation from Oxford Sparks, Dr Benjamin Brecht from Oxford's Department of Physics explores the 'miraculous' world of quantum physics, focusing on remarkable pieces of light known as photons.

Dr Brecht says: 'Quantum physics opens a window to a miraculous world, where extraordinary things happen that cannot be explained by our everyday experience. Things like quantum teleportation sound like science fiction, but they are being realised today in quantum laboratories. If we can harness these exciting phenomena, we can build new technologies that outperform their existing, classical counterparts. This vision of the future fascinates me and makes we want to add my small contribution to the pool of outstanding ideas.'

Oxford Sparks is a great place to explore and discover science research from the University of Oxford. Oxford Sparks aims to share the University's amazing science, support teachers to enrich their science lessons, and support researchers to get their stories out there. Follow Oxford Sparks on Twitter @OxfordSparks and on Facebook @OxSparks.

A new approach to improving hemispatial neglect after stroke

Jacinta O'Shea from the Nuffield Department of Clinical Neurosciences explains how stimulation of the brains of stroke patients can cause long-lasting improvements.

Every year thousands of people are left with debilitating symptoms after stroke. Perhaps one of the most striking is known as hemispatial neglect. This is when right-sided brain damage causes people to behave as though the left half of the world does not exist.

This problem arises when damage to the right parietal cortex disrupts the connections linking visual areas at the back of the brain with motor systems towards the front. The damage leaves the stroke survivor unable to voluntarily direct attention towards, and act on, visual objects in the space to their left.

Hemispatial neglect is very common, affecting many patients in the early months after stroke. Most recover over time, but about one-third do not, and suffer neglect as a lasting disabling condition.

The orthodox approach

To date there is no clinically established treatment, although researchers are developing promising methods to improve the condition. These methods focus either on changing patients’ brain activity or changing their behaviour.

One such approach is non-invasive brain stimulation. Damage to the right side of the brain causes the (undamaged) left side to become hyperactive. Suppressive stimulation of the (undamaged) left parietal cortex can reduce this hyperactivity. By ‘rebalancing’ brain activity in this way, neglect improves, but the effect lasts only for a few minutes.

Another approach is a behavioural therapy known as ‘prism adaptation’. Patients wear glasses containing prisms, which bend light, causing objects to appear to be shifted to the right. This results in a mismatch between where a patient sees an object and where they need to move their hand in order to touch that object. With training, patients learn to adapt to the prisms, by shifting their hand-eye coordination leftwards, towards the neglected half of space. This training improves many symptoms of neglect, such as postural imbalance and reading – but the benefit usually lasts only for 24 hours after training.

If either approach is repeated daily over several weeks the improvements can last for several weeks. However, this intensive repetition is time-consuming, labour-intensive, and costly.

A novel approach

Working with colleagues at the University of Lyon, France, we investigated whether it might be possible to use brain stimulation to improve how patients learn during prism adaptation, to make the therapy more efficient. In contrast to the traditional brain stimulation approach, which involves inhibiting brain activity in the left parietal cortex, instead we excited the left sensorimotor cortex, a brain region important for retaining newly learned motor skills. We reasoned that this might strengthen memory for prism adaptation training, which could cause longer-lasting improvements in neglect.

First, we tested this idea using tDCS (trans-cranial direct current stimulation), a mild form of non-invasive brain stimulation, in healthy volunteers during prism adaptation. We discovered that exciting the left sensorimotor cortex did indeed cause long-lasting memory of the adaptation task. Having established that this worked in healthy volunteers, we then carried out longitudinal case studies with three patients with hemispatial neglect. What we found surpassed our expectations.

In the early stage after stroke, these patients had shown improvements after prism therapy. But in the ‘chronic’ stage, over one year later, although the patients still adapted to prisms, this no longer caused any improvement. In different sessions in our study the patients performed prism therapy combined with real and fake tDCS. We then tested whether each patient’s neglect symptoms changed over time. We found that just one 20-minute session of real (but not fake) stimulation during prism therapy resulted in improvements in neglect that lasted for weeks to months and did not return to the baseline.

A new approach to improving hemispatial neglect after strokeThe patient was asked to distribute flowers equally around the garden. They are all clumped to the right, showing dramatic neglect of left space.

Our prediction that stimulation would strengthen the memory trace formed during adaptation, and cause neglect improvements to last for a long time, was proved correct. The duration of the improvement was surprising; moreover, it appeared to be cumulative, with each combined stimulation/therapy session building on the last.

Implications for stroke recovery

For these long-term ‘treatment-resistant’ stroke patients involved in the study, this was proof that they still have the capacity to make cognitive gains. We have established, for the first time, that it is possible to ‘switch back on’ or ‘reawaken’ plasticity in dormant brain circuits of patients suffering chronic neglect, more than one year after stroke, with the therapy gains lasting much longer than expected.

We’re now testing this in a larger group of patients in a randomised controlled clinical trial using a more intensive training regime. If the findings replicate, our approach will be a nice example of how we can take ideas from the neuroscience laboratory into the clinic to help improve stroke patients’ lives.

The full paper, 'Induced sensorimotor cortex plasticity remediates chronic treatment-resistant visual neglect', can be read in eLife Sciences.

This research was funded by a Royal Society Dorothy Hodgkin Fellowship to Jacinta O'Shea, with support from the Oxford Biomedical Research Centre.

Words by Jacqueline Pumphrey and Dr Jacinta O'Shea, NDCN.