Could gene-edited ticks make Lyme disease an ailment of the past?

Lyme disease could become a thing of the past as scientists believe they may soon be able to stop ticks transmitting the bacterial infection.

US experts have found a way of editing the genes of the spider-like creatures, which feed on blood.

It opens the possibility to researchers being able to alter parts of a tick’s DNA that helps them carry and transmit the disease-causing bacteria. 

And the discovery could pave the way for genetically-engineered ticks, which are unable to spread illness, to be released into the wild.

A similar tactic has already been used on mosquitoes as part of trials to cut the spread of malaria and dengue fever. 

The approach involves using the CRSIPR/Cas9 system, which works like a pair of DNA scissors. 

It would see ticks injected with an enzyme that cuts off a chunk of their DNA that allows it to carry the bacteria that triggers Lyme disease.

It was thought to be impossible to use this technology on ticks because their eggs are coated in a hard wax that injections can’t get through. 

But now a team at the University of Nevada have found a way around it, by using the Crispr tool to alter the ovaries of ticks so that their eggs aren’t coated with wax but stay viable. 

This enabled scientists to inject their eggs and delete troublesome genes.

Results, published in the journal iScience, showed it worked in one in seven cases, meaning it could be used in the future. 

They also tested injecting the enzyme that cuts off Lyme disease bacteria directly into pregnant female ticks, so it interfered with their offspring’s DNA.

This was slightly less successful, working in one in nine cases.  

Professor Jason Rasgon, an epidemiologist at Penn State University and developer of the technology, said: ‘Ticks are a formidable foe to public health.

‘We are in desperate need of new tools to fight ticks and the pathogens they spread.

‘The (two gene-editing) methods can be used to develop new control methods for disease and also to further understand the biology of ticks.’

Lyme disease is a bacterial infection spread through a tick bite. Although not all ticks — which lurk in the woods and grassy areas — carry the bacteria.

It causes a round rash and can trigger flu-like symptoms but usually gets better with antibiotics within weeks or months.

However, some people develop symptoms, including tiredness, aches and a loss of energy, that can last for years.

There is currently no vaccine and existing antibiotic treatments are not always effective.

Around 900 Lyme disease cases are reported in the UK every year but the true toll is thought to be in the region of 3,000. Figures are up to 30 times higher in the US. 

Dr Monika Gulia-Nuss, co-author of the study, said: ‘Despite their capacity to acquire and pass on an array of debilitating pathogens, research on ticks has lagged behind other arthropod vectors, such as mosquitoes, largely because of challenges in applying available genetic and molecular tools.

‘Previously, no lab has demonstrated genome modification is possible in ticks. Some considered this too technically difficult to accomplish.

‘This is the first study to demonstrate that genetic transformation in ticks is possible by not only one, but two different methods.’

Other tick-borne diseases include babesiosis, which infects and destroys red blood cells and tick-borne encephalitis virus, which attacks the central nervous system. 

Only a handful of cases of each have ever been spotted in the UK. 

Both trigger flu-like symptoms, but the immunocompromised can have more severe illness and die.

Ticks can also transmit bacteria to wildlife and domestic animals. 

Experts warn climate change is allowing tickets to spread to new areas, putting more people and animals at risk of infection.