In the past five decades, the United States has witnessed a significant rise in tick-borne diseases, prompting urgent calls from scientists at Yale University for innovative solutions. A recent review conducted by the research team highlights the alarming spread of these diseases, which can be attributed to factors such as increased deer populations and forest regrowth, as well as the dominance of the deer tick in transmissions.

According to the researchers, traditional vaccines have had limited success in combating tick-borne diseases, necessitating the exploration of new strategies that target tick-feeding processes and alert mechanisms. The proposal put forward by the team also emphasizes the expansion of these tactics to wildlife, requiring a collaborative and multidisciplinary approach akin to the Manhattan Project to effectively address this growing public health threat.

Led by Sukanya Narasimhan, associate professor in Yale's Department of Internal Medicine (Infectious Diseases), and Erol Fikrig, Waldemar Von Zedtwitz Professor of Medicine (Infectious Diseases) and professor of epidemiology (microbial diseases) and microbial pathogenesis, the team cautions that the surge in tick-borne diseases poses a significant risk to public health. Recognition of this threat only occurred in 1982 after an outbreak of arthritis-like symptoms in children in Lyme, Connecticut, caused by a bacterium transmitted by ticks.

Since then, the number of tick-borne disease cases has increased dramatically, with an estimated 490,000 people in the United States being infected annually. This rise has been fueled by the resurgence of forests and an exponential increase in the population of tick-hosting white-tailed deer. Unsurprisingly, the threat has spread from isolated areas near the New England coastline to the Midwest and other parts of the country.

Alarmingly, a single tick species, the black-legged or deer tick (Ixodes scapularis), is responsible for 97% of tick-borne diseases in the United States. While efforts have primarily focused on developing vaccines targeting the bacterium Borrelia burgdorferi, which causes Lyme disease, these endeavors have had limited success and do not address other pathogens transmitted by ticks.

In response to the rapid rise in tick-borne diseases, researchers at Yale, especially in Erol Fikrig's lab, are developing vaccines that target various infections by disrupting tick feeding processes and alerting individuals when they have been bitten. By preventing ticks from feeding, the researchers believe they can effectively control Lyme disease and other tick-borne infections.

Previous studies have shown that multiple exposures to tick bites can increase resistance to tick-borne infections. Building on this knowledge, the team at Yale has developed a vaccine containing a combination of tick salivary proteins. This vaccine has shown promise in impairing tick feeding and increasing individuals' ability to recognize when they have been bitten, leading to quicker tick removal and a reduced risk of infection.

Durland Fish, a co-author of the review and professor emeritus of epidemiology (microbial diseases) at Yale School of Public Health, suggests that such a vaccine could be delivered orally within bait consumed by deer. If successful, this approach could significantly reduce tick populations and the subsequent risk of tick-borne diseases for humans. Similar strategies have proven effective in the prevention of raccoon rabies in the United States and fox rabies in Europe, as well as the protection of cattle against tick-borne diseases.

In conclusion, the researchers stress the need for a multidisciplinary and integrated approach, known as One Health, that considers the health of humans, animals, and ecosystems in combatting tick-borne diseases. The vision of molecular biologists, entomologists, ecologists, epidemiologists, physicians, veterinarians, and vaccinologists must be harnessed to effectively address this escalating public health threat. With the urgent call for innovative solutions, Yale University researchers hope to make significant strides in mitigating the impact of tick-borne diseases on society.