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Updated: Nov 21, 2025
Modeling Tuberculosis in Mycobacterium marinum Infected Adult Zebrafish
Published on: October 8, 2018
Natural resistance to worms exacerbates bovine tuberculosis severity independently of worm coinfection
Vanessa O Ezenwa1,2, Sarah A Budischak3, Peter Buss4
1Odum School of Ecology, University of Georgia, Athens, GA 30602; vezenwa@uga.edu.
Abstract:
Pathogen interactions arising during coinfection can exacerbate disease severity, for example when the immune response mounted against one pathogen negatively affects defense of another. It is also possible that host immune responses to a pathogen, shaped by historical evolutionary interactions between host and pathogen, may modify host immune defenses in ways that have repercussions for other pathogens. In this case, negative interactions between two pathogens could emerge even in the absence of concurrent infection. Parasitic worms and tuberculosis (TB) are involved in one of the most geographically extensive of pathogen interactions, and during coinfection worms can exacerbate TB disease outcomes. Here, we show that in a wild mammal natural resistance to worms affects bovine tuberculosis (BTB) severity independently of active worm infection. We found that worm-resistant individuals were more likely to die of BTB than were nonresistant individuals, and their disease progressed more quickly. Anthelmintic treatment moderated, but did not eliminate, the resistance effect, and the effects of resistance and treatment were opposite and additive, with untreated, resistant individuals experiencing the highest mortality. Furthermore, resistance and anthelmintic treatment had nonoverlapping effects on BTB pathology. The effects of resistance manifested in the lungs (the primary site of BTB infection), while the effects of treatment manifested almost entirely in the lymph nodes (the site of disseminated disease), suggesting that resistance and active worm infection affect BTB progression via distinct mechanisms. Our findings reveal that interactions between pathogens can occur as a consequence of processes arising on very different timescales.
Insights
Natural resistance to parasitic worms worsens bovine tuberculosis (BTB) outcomes in wild mammals, independent of active infection. Worm-resistant animals showed faster disease progression and higher mortality from BTB.
Area of Science:
- Ecology and Evolutionary Biology
- Immunology
- Veterinary Medicine
Background:
- Pathogen interactions, including coinfections, can worsen disease severity.
- Host immune responses shaped by past interactions can influence susceptibility to other pathogens.
- Parasitic worms and tuberculosis (TB) interactions are geographically widespread, with worms exacerbating TB during coinfection.
Purpose of the Study:
- To investigate if natural resistance to parasitic worms affects bovine tuberculosis (BTB) severity independently of active worm infection.
- To determine the mechanisms by which worm resistance and anthelmintic treatment influence BTB pathology.
Main Methods:
- Studied a wild mammal population naturally exposed to parasitic worms and bovine tuberculosis (BTB).
- Assessed the impact of natural worm resistance and anthelmintic treatment on BTB severity, mortality, and disease progression.
- Examined the pathological effects of worm resistance and anthelmintic treatment on BTB in lungs and lymph nodes.
Main Results:
- Worm-resistant individuals exhibited increased mortality and faster disease progression from BTB compared to non-resistant individuals.
- Anthelmintic treatment mitigated, but did not eliminate, the effect of worm resistance on BTB mortality.
- Worm resistance primarily affected lung pathology, while anthelmintic treatment impacted lymph node pathology, suggesting distinct mechanisms.
Conclusions:
- Host resistance to parasitic worms can negatively impact susceptibility to bovine tuberculosis, even without active worm infection.
- Pathogen interactions can occur across different timescales, influenced by historical host-pathogen evolutionary relationships.
- Understanding these complex interactions is crucial for managing wildlife diseases and public health.
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