With DNA test against snake venom

Identification of the snake species after a bite allows faster countermeasures

Head of a krait whose poison can be deadly. © AshLin / (CC BY-SA 2.5)
Read out

Quick help with deadly bites: A DNA test can speed up the treatment of snakebites and make them more efficient. In order to provide not only fast, but above all the right therapy after a bite, doctors in Nepal have used such a DNA test in a clinical study for the first time. The result: If snake DNA can be obtained from the bite wound, the result always leads to the correct treatment.

Snake bites are a serious threat to people in much of the world. Accurate figures are not available, but experts assume that millions of people are bitten by poisonous snakes every year. Hundreds of thousands die or survive only with severe disabilities. Fast countermeasures are therefore important - but they also have to be the right ones. However, in most cases it is not clear which type of snake caused the bite. This information is crucial for the right treatment.

Wrong antivenin can be fatal

The bites of the cobra and the krait, for example, two of the most common types of snakes in Nepal, both lead to symptoms such as dizziness, nausea and paralysis to death by respiratory arrest. However, the molecular mechanisms of action of the toxins of both snakes differ fundamentally. The usual local antidote to Kobrabisse therefore does not work against the poison of krait. Out of ignorance, some patients receive several doses of the wrong remedy, which not only does not help but can also lead to serious side effects.

A DNA test should therefore make the treatment of snake bites faster, above all, more reliable. Ulrich Kuch from the University Hospital Frankfurt am Main has developed such a test with his colleagues and tested it in a clinical study in Nepal. From around a quarter of all bite wounds, the doctors were able to isolate DNA of the snake, a total of 194 cases. In the remaining cases, patient cleanup made DNA retrieval difficult.

With the isolated DNA, however, the researchers were able to correctly identify the snake species by means of specific gene sequences. Twenty-one patients had also brought the snake that had bitten them to the clinic so that the researchers could independently test and confirm their test result. display

The Indian cobra is one of the most dangerous snakes on the Indian subcontinent. Pavan Kumar N / (CC BY-SA 3.0)

Improved diagnostics, higher chances of survival

The DNA test revealed that 87 of the identified snakes were toxic the remainder were relatively harmless. Again, this is an important finding: Snakebite victims usually stay in the hospital for 24 hours for observation. If it turns out early on that the bite is not dangerous, this relieves the clinic and costs less money. On the other hand, if a certain poisonous snake species is detected, the doctors can immediately administer the right antidote without waiting for serious and possibly irreversible symptoms of intoxication.

"The study results are an important step towards better medical care in regions where snake bites pose a significant health risk, " says Kuch. The DNA test can improve the diagnosis and thus the chances of the patients on survival and complete recovery.

Quick test for everyday life

The scientists around Kuch are currently developing a rapid procedure to make the test usable in everyday life beyond a clinical trial. This quick test is designed to work much like a pregnancy test and to detect the snake venom in the patient's blood. This would make sense especially for remote regions in developing countries: "Especially here, robust, easy-to-use, specific and sensitive rapid tests are particularly valuable, " explains Kuch, "because they help in an uncomplicated way. Patients sooner and better to treat and use the limited medical resources effectively. "

The data collected in the DANN test also allows conclusions to be drawn about the species diversity among the snakes in a region. With this information in turn, specific antivenoms could be delivered more efficiently to the right areas.

(University Hospital Frankfurt, 05.11.2014 - AKR)