2023-08-29 08:00:39
In recent years, between 41 and 104 cases of Lyme disease per 100,000 inhabitants have been recorded annually in France, with significant annual and regional disparities. INRAE, ANSES and the National Veterinary School have recently developed an innovative vaccine capable of reducing infection by bacteria Borrelia in the event of a tick bite.
tick, Borrelia and Lyme disease
Every year, the tick bites multiply from spring to autumn, especially in the countryside and mountainous areas, frequented by hikers and campers. Beyond the discomfort caused and the often minor symptoms caused by the tick bite, the main risk is the transmission of bacteria of the genus Borreliaresponsible in particular for Lyme disease. While Lyme disease isn’t the only tick-borne illness, it’s arguably the most well-known. Eight out of 10 French people have already heard of it.
Lyme disease can manifest in several ways:
- An early localized form, erythema migrans: an inflammatory red plaque appears around the point of the bite then spreads gradually, without itching or fever. The appearance of this erythema requires consulting a doctor to set up an antibiotic treatment for the infection.
- Disseminated early forms: erythema migrans appear at the level of the sting area but also at other places of the body. Other symptoms may be present, such as fever, headache, fatigue, muscle or joint pain. Again, medical advice and antibiotic treatment are necessary.
- Variable early forms during the 6 months following the bite: arthritis, skin lesions, neurological damage, cardiac damage, ophthalmological damage. Often more difficult to link with the tick bite, the diagnosis can be more complex.
- Late forms if no antibiotics were given during the early stages of the infection. These forms appear at least 6 months after the bite and evolve over time, with skin, neurological, joint, cardiac, ophthalmological or cognitive disorders. The diagnosis is often difficult to make, but antibiotic treatment is still necessary.
A vaccine targeting the microbiota of the tick
Faced with this borreliosisand even if the adapted antibiotic treatments generally allow the cure, the researchers try to develop a vaccine to protect against infection at the time of the tick bite. Recently, researchers from INRAE, ANSES and the National Veterinary School of Alfort developed an innovative vaccine, targeting tick microbiotain which the bacteria are found Borrelia responsible for Lyme disease.
This vaccine disrupts the microbiota of the tick to indirectly protect against Lyme disease. In their studies, the researchers injected mice with a non-pathogenic bacterium. In the organism of the mouse, this bacterium leads to the production of antibodies. If the mouse is then bitten by a tick, the antibodies interact with the tick’s microbiota and modify it. This vaccination of mice reveals that vaccinated mice carry fewer bacteria Borrelia than unvaccinated mice.
The microbiota, an interesting target for other vector-borne diseases?
The vaccination method developed here is indirect since the vaccine limits contamination by bacteria Borrelia, but does not block the development of Lyme disease. This innovative vaccine therefore does not provide complete protection for mice against Lyme disease, but reduces the rate of bacterial colonization. This work confirms the key importance of the tick microbiota in the development of Borrelia in the tick, then in the transmission of Borrelia to the man during the sting. They also offer for the first time a possibility of protecting oneself, at least partially, against Lyme disease and its consequences.
For researchers, the development of a first vaccine targeting the microbiota opens up new perspectives. Indeed, other vector-borne diseases are transmitted by sting or bite, such as malaria or dengue fever. Deciphering the role of the microbiota, in which bacteria, viruses or parasites live, and modifying the microbiota to reduce the risk of transmission of pathogens to humans could be interesting approaches in the global fight against vector-borne diseases.
Posted on August 4, 2020 by Suzanne L., Pharmacist & Scientific Writer. Updated by Estelle B., Doctor of Pharmacy on August 29, 2023.
Sources
– Wu-Chuang A., Mateos-Hernandez L., Maitre A. et al. microbiomejournal.biomedcentral.com. Accessed August 8, 2023.
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