Bacillus thuringiensis attacking ticks

Tick Talk: Could Bacteria Be the Unsung Heroes of Tick Control?

Mira Elwood in Science & Nature December 2025 • 4 min read.

"New research explores the potential of Bacillus thuringiensis strains as a bio-friendly solution to combat Ixodes ricinus and Dermacentor reticulatus ticks."

Arthropod population control often relies on physical, chemical, and biological methods. Among these, biological methods are gaining traction for their eco-friendly properties, employing either micro-predators (microbiological agents) or macro-predators (vertebrates, arthropods, nematodes).

Within the realm of microorganisms, Gram-positive bacteria like Bacillus thuringiensis Berliner 1915 are commonly utilized as biological insecticides. Their pathogenic effect on arthropods is mainly linked to the production of proteins such as δ-endotoxin (crystal or Cry proteins) during sporulation.

Recent research has investigated the potential of environmental and commercial Bacillus thuringiensis strains against Ixodes ricinus and Dermacentor reticulatus ticks, both significant vectors of tick-borne diseases in Europe. This study marks a crucial step towards exploring biological methods for tick control.

The Science of Tick Control: Bacillus Thuringiensis and Its Potential

The study evaluated four environmental strains of B. thuringiensis along with a commercially available product (Vectobac) to determine their effectiveness against ticks. While Vectobac proved ineffective, two of the environmental B. thuringiensis strains demonstrated significant potential against both Ixodes ricinus and Dermacentor reticulatus. These strains exhibited mortality rates of up to 80%, with LC50 values ranging between 9.1 × 10⁶ and 1.3 × 10¹⁵ cfu/ml.

Interestingly, Dermacentor reticulatus males were found to be the most susceptible to the bacteria. Further analysis of the enzymatic profiles of both the most and least efficient B. thuringiensis strains—including lipases, phosphatases, proteases, and chitinases—suggests that these enzymes may play a limited role in the bacteria's pathogenicity profile against ticks.

Strain Variations: Different strains of B. thuringiensis exhibit varying levels of efficacy against ticks.
Mortality Rates: Some strains can achieve high mortality rates, offering a promising avenue for tick control.
Enzyme Analysis: The role of specific enzymes in the pathogenicity of B. thuringiensis against ticks appears to be limited.

The findings indicated that the B. thuringiensis QpB11 strain was the most pathogenic, with LC50 values of 10⁶ cfu/ml for D. reticulatus males and 10¹¹ cfu/ml for I. ricinus females, resulting in 30-80% mortality rates. The B. thuringiensis KpC1 strain was effective against males of both tick species, with mortality rates of up to 80% and an LC50 level of 10⁷ cfu/ml.

Looking Ahead: Future Directions in Biological Tick Control

The study's results highlight the potential of B. thuringiensis as a biological control agent for managing tick populations, particularly I. ricinus and D. reticulatus, which are primary vectors of tick-borne diseases in Europe. This approach could provide a more sustainable and environmentally friendly alternative to traditional chemical methods.

However, the precise mechanisms of B. thuringiensis's interaction with ticks, including the role of δ-endotoxins and specific enzymes, require further investigation. Understanding these factors is crucial for optimizing the effectiveness and safety of B. thuringiensis-based tick control strategies.

Further research is needed to assess the long-term effects of B. thuringiensis on tick populations and the broader ecosystem. Evaluating its impact on non-target organisms and the development of resistance in tick populations will be essential for ensuring the sustainable use of this biological control agent.

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This article is based on research published under:

DOI-LINK: 10.1007/s00436-018-6096-z, Alternate LINK

Title: Sensitivity Of Ixodes Ricinus (L., 1758) And Dermacentor Reticulatus (Fabr., 1794) Ticks To Bacillus Thuringiensis Isolates: Preliminary Study

Subject: Infectious Diseases

Journal: Parasitology Research

Publisher: Springer Science and Business Media LLC

Authors: Anna Szczepańska, Dorota Kiewra, Katarzyna Guz-Regner

Published: 2018-10-15

Everything You Need To Know

Could Bacillus thuringiensis bacteria really be a solution for controlling ticks?

Research indicates that certain environmental strains of Bacillus thuringiensis show promise in controlling Ixodes ricinus and Dermacentor reticulatus ticks. These strains, such as QpB11 and KpC1, have demonstrated significant mortality rates against these ticks, offering a potential alternative to chemical methods. However, the commercial product Vectobac was found to be ineffective in this study. Further research is needed to understand why certain environmental strains work better than commercial products.

Why are some types of Bacillus thuringiensis better at killing ticks than others?

The study found that different strains of Bacillus thuringiensis exhibit varying levels of effectiveness against ticks. For example, the B. thuringiensis QpB11 strain showed high pathogenicity, especially against Dermacentor reticulatus males and Ixodes ricinus females, while the KpC1 strain was effective against males of both tick species. This highlights the importance of strain selection when considering Bacillus thuringiensis as a biological control agent. Future studies could explore the genetic factors behind these differences.

Do enzymes like lipases or proteases from Bacillus thuringiensis play a big role in killing ticks?

The research suggests that enzymes like lipases, phosphatases, proteases, and chitinases may have a limited role in the pathogenicity of Bacillus thuringiensis against ticks. While these enzymes are typically associated with the bacteria's pathogenic mechanisms in other arthropods, their contribution to tick mortality appears to be less significant. It’s important to investigate other factors, like Cry proteins or other toxins produced by Bacillus thuringiensis, to fully understand how it affects ticks.

What are the environmental benefits of using Bacillus thuringiensis for tick control instead of chemicals?

Using Bacillus thuringiensis as a biological control agent could significantly reduce the reliance on chemical methods for tick control. Chemical methods can have adverse effects on the environment and non-target organisms. Bacillus thuringiensis offers a more sustainable and environmentally friendly approach, particularly for managing Ixodes ricinus and Dermacentor reticulatus ticks, which are vectors of tick-borne diseases in Europe. This is because Bacillus Thuringiensis is a naturally occurring bacteria and can be targeted at specific pests.

How effective is Bacillus thuringiensis QpB11 against different types of ticks?

The most pathogenic Bacillus thuringiensis QpB11 strain exhibited LC50 values of 10⁶ cfu/ml for Dermacentor reticulatus males and 10¹¹ cfu/ml for Ixodes ricinus females, resulting in 30-80% mortality rates. The B. thuringiensis KpC1 strain was effective against males of both tick species, with mortality rates of up to 80% and an LC50 level of 10⁷ cfu/ml. LC50, or median lethal concentration, is the concentration of a substance required to kill half of a test population. Lower LC50 values indicate higher toxicity.