Scientists hope to mimic blood-sucker’s tricks
Patients could stand to benefit from medical study of the tick
By Lori Reid
THEY are known as a threat to both humans and animals, spreading disease to their prey.
But scientists now believe blood-sucking ticks can be helpful to humans in various medical therapies.
Ticks spread disease and paralysis to livestock and, if bitten by a tick carrying lyme disease, humans can develop arthritis and neurological problems.
Despite this, researchers now believe that ticks might help people and are studying the creatures’ saliva to see if they can harness its properties and create new blood clot drugs as well as therapies for inflammatory and auto-immune diseases.
Ticks, Biology, Disease and Control, a new book co-edited by Alan Bowman of Aberdeen University, looks into the threat and potential of ticks.
Mr Bowman said: “Ticks have this really neat trick where they feed on their host for two weeks and are able to do so unnoticed. We are trying to find the factors that allow their saliva to deliver anticoagulants, immunosuppressants, anti-inflammatories and painkillers to the host which means the animal is not aware it is being feasted on.
“If we could mimic these properties it may help us find new therapies for conditions like thrombosis, as well as new anti-inflammatory and auto-immune treatments.”
Mr Bowman also states the threat ticks have to animals.
He said: “There is a desperate need to find new control strategies for ticks, which are found on eight out of 10 cattle worldwide and have been called ticking time bombs.
“Ticks are a serious concern worrying governments across the globe and the World Health Organisation because the creatures are becoming more and more resistant to the chemicals that we are using to treat them.”
Ticking timebombs exposed in new book
The number of reported Lyme disease cases in people has risen in Scotland 25 fold over the last decade.
This is believed to be due to milder winters; a rise in the population of deer, which carry ticks; more people enjoying outdoors pursuits; changes in the Right to Roam laws, and an increased awareness of the problem.
Despite all of the above, ticks may actually help people.
Scientists are studying the creatures’ saliva to see if they can harness its properties and create new blood clot busting drugs as well as therapies for inflammatory and auto immune diseases.
The problems and potential of ticks are explored in-depth in the new book Ticks Biology, Disease and Control which is co edited by Dr Alan Bowman from the University of Aberdeen and Professor Patricia Nuttall at NERC’s Centre for Ecology and Hydrology, Wallingford.
He said: “Ticks are a serious concern worrying Governments across the globe and the World Health Organisation because the creatures are becoming more and more resistant to the chemicals that we are using to treat them.
“There is a desperate need to find new control strategies for ticks which are found on 8 out of 10 cattle worldwide and have been called ticking timebombs.”
Dr Bowman is one of the scientists involved in the race for new treatments to protect livestock.
The tick expert is also involved in collaborations which are exploring the potential of the bloodfeeder’s saliva in a pursuit coined by Wall Street as “Mining Bugs for Drugs”.
“Ticks have this really neat trick where they feed on their host for two weeks and are able to do so unnoticed,” said Dr Bowman
“We are trying to find the factors that allow their saliva to deliver anticoagulants, immunosuppressants, anti inflammatories and pain killers to the host which means the animal is not aware it is being feasted on.
“If we could mimic these properties it may help us find new therapies for conditions like thrombosis, as well as new anti-inflammatory and auto-immune treatments.
“Instead of starting from scratch in developing new drugs and re-inventing the wheel we should see how Mother Nature has tackled the problem over the millions of years that ticks have been feeding on mammals ”
Ticks provide anti-clotting drug
27 August 2009
Scientists have tapped into nature’s medicine chest to develop a new drug that can control blood flow and prevent clotting, potentially preventing a stroke or heart attack.
The UK and Slovakian research team discovered and isolated an anticoagulant, or anti-clotting agent, from the salivary glands of ticks. They believe the ticks secrete the anticoagulant to keep their host’s blood flowing while they feed.
Recognising the potential for this natural anti-clotting agent, which they called Variegin, the researchers teamed up with experts in snake venom peptides from the National University of Singapore, who used chemical synthesis to reproduce Variegin and make it more potent.
‘By synthesising and modifying the anticoagulant our partners in Singapore were really able to understand how it works and to improve its functions,’ explains Professor Patricia Nuttall from the UK’s Centre for Ecology & Hydrology. ‘As well as enabling blood to flow freely, we may now be able to stop the effect so that clotting is restored. This is an important breakthrough as it will potentially enable the development of new blood-controlling drugs with a much better performance level – and therefore fewer adverse side effects – than some of those currently available.’
Snake venom expert Professor Manjunatha Kini at the National University of Singapore thinks that, although ticks have developed very potent and specific anti-clotting molecules that allow them to freely enjoy their blood-sucking lifestyle, there is still room for improvement. ‘By understanding how Variegin works we were able to reduce its size and at the same time improve its potency with suitable modifications,’ he says.
They now have molecules of different sizes, levels of potency and duration of effect. ‘One of the molecules has 70 times more potency and anti-clotting effect than a drug that is currently on the market,’ says the National University of Singapore’s Dr Cho Yeow Koh.
To test the performance of Variegin, the scientists carried out initial tests on zebrafish. They used a model established by Dr Pudur Jagadeeswaran from the University of North Texas to see if Variegin could prevent venous thrombosis – and subsequently be used to prevent deep vein thrombosis in humans.
‘The tests were a huge success and completely inhibited thrombus formation, ‘says Nuttall. ‘We still have a long way to go but if we can get Variegin into clinical trials it could have potential applications for coronary diseases, deep-vein thrombosis and be applied during major surgery to control bleeding. There is also evidence that, by controlling blood flow and clotting, the spread of some cancers could be diminished or prevented.’