Sequencing data could be used to prevent lyme disease

By Dr. Ananya Mandal, MDJul 25 2019

Lyme disease is caused by the bacterium and is transmitted to humans by the bites of black-legged ticks. The incidence of this disease is on the rise and now researchers have made a significant advance towards understanding this disease and preventing its transmission.

Now, a team of researchers from the University of California, Irvine, and colleagues has successfully sequenced the genome of the animal that could carry the bacteria causing Lyme disease.

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Lyme disease is characterized by headache, fatigue and fever along with a skin rash called erythema migrans. The infection is capale of spreading to the nervous system, heart and joints. Insect repellents to prevent tick bites are the only way to prevent transmission of this infection says the Centers for Disease Control and Prevention (CDC).  Treatment for this condition is a course of antibiotics.

Uncovering a ‘genetic blueprint’ for the prevention of Lyme disease

It took over four years for the researchers of the current study to decipher the genetic code of the white-footed mouse (Peromyscus leucopus), that is a known carrier of the Lyme disease-causing bacteria. These mice usually do not stay inside homes and are found in the forests and wetlands explain the researchers.

Ticks become infected with the bacteria when they bite the mice. The infection is subsequently passed on to humans when they are bitten by a tick.

Many efforts to combat Lyme disease have focused on trying to control those ticks, but they have been difficult to put in practice. So we decided that instead we should look at the animal carrying it.”

Alan Barbour, Lyme Disease Expert

Barbour is the professor of medicine and microbiology & molecular genetics for the UCI School of Medicine and was one of the co-discovers of Borreliella burgdorferi – the causative bacteria of Lyme disease.

Anthony Long, Ph.D., professor of ecology & evolutionary biology in the UCI School of Biological Sciences, along with Barbour and other researchers looked at the white-footed mice and the role they played in the life cycle of this bacteria causing Lyme disease.

They looked at the genetic sequence of these mice and found that its genome is similar in size as the human genome.

Long explained, “If you want to understand a species, knowing its genetic blueprint is invaluable. It provides a road map that makes new research approaches much faster and more efficient. While these rodents are called mice, they are more closely related to hamsters than to the house mouse and the researchers' new data emphasized this fact.”

Eliminating Lyme disease from the environment

Now that the genome of the mouse has been sequenced, the researchers will begin working on methods to prevent the transmission of Lyme disease. One of the potential methods is a humane and safe method of vaccinating the white-footed mice in the wild. This process is already in place for prevention of rabies among wild animals.

Barbour added that this study helps scientists understand why the bacteria do not cause Lyme disease in the mice but goes on to infect humans:

Understanding what shields [white-footed mice] from getting sick could guide us in protecting humans from it.”

He added that there are several such ailments which do not affect the rodents that carry them including viral encephalitis, Rocky Mountain spotted fever etc.

To allow other scientists to chip in with their research on the prevention of Lyme disease transmission, the team has allowed the full genomic sequence of the white-footed mouse to be accessed freely.

The CDC website outlines the methods by which people could protect themselves from tick bites and Lyme disease. Between 2016 and 2017, there was a 17 percent rise in the incidence of Lyme disease from 36,429 to 42,743.

Acknowledgments

The study was published in the latest issue of the journal Science Advances and was assisted by researchers from UC Santa Cruz and the University of Utah. It was supported by the National Institute of Allergy and Infectious Diseases.