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Updated: Jun 13, 2026
Infection of Zebrafish Larvae with Aspergillus Spores for Analysis of Host-Pathogen Interactions
Published on: May 16, 2020
Embryonated eggs as an alternative infection model to investigate Aspergillus fumigatus virulence
Ilse D Jacobsen1, Katharina Grosse, Silvia Slesiona
1Department for Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany. ilse.jacobsen@hki-jena.de
Abstract:
Infection models are essential tools for studying microbial pathogenesis. Murine models are considered the "gold standard" for studying in vivo infections caused by Aspergillus species, such as A. fumigatus. Recently developed molecular protocols allow rapid construction of high numbers of fungal deletion mutants, and alternative infection models based on cell culture or invertebrates are widely used for screening such mutants to reduce the number of rodents in animal experiments. To bridge the gap between invertebrate models and mice, we have developed an alternative, low-cost, and easy-to-use infection model for Aspergillus species based on embryonated eggs. The outcome of infections in the egg model is dose and age dependent and highly reproducible. We show that the age of the embryos affects the susceptibility to A. fumigatus and that increased resistance coincides with altered chemokine production after infection. The progress of disease in the model can be monitored by using egg survival and histology. Based on pathological analyses, we hypothesize that invasion of embryonic membranes and blood vessels leads to embryonic death. Defined deletion mutant strains previously shown to be fully virulent or partially or strongly attenuated in a mouse model of bronchopulmonary aspergillosis showed comparable degrees of attenuation in the egg model. Addition of nutrients restored the reduced virulence of a mutant lacking a biosynthetic gene, and variations of the infectious route can be used to further analyze the role of distinct genes in our model. Our results suggest that embryonated eggs can be a very useful alternative infection model to study A. fumigatus virulence and pathogenicity.
Insights
Embryonated eggs offer a reproducible, low-cost alternative for studying Aspergillus fumigatus infections. This model effectively screens fungal mutants, reducing the need for animal experiments in pathogenesis research.
Area of Science:
- Mycology
- Infectious Diseases
- Animal Models
Background:
- Murine models are standard for Aspergillus fumigatus pathogenesis studies.
- Developing alternative models is crucial to reduce animal use.
- Invertebrate and cell culture models exist but lack direct correlation to mammalian systems.
Purpose of the Study:
- To develop and validate a novel, cost-effective infection model for Aspergillus species using embryonated eggs.
- To assess the utility of the egg model in evaluating fungal virulence and pathogenicity.
- To correlate findings in the egg model with established murine models.
Main Methods:
- Infection of embryonated eggs with Aspergillus fumigatus.
- Dose- and age-dependency studies of infection outcomes.
- Histological analysis and monitoring of egg survival.
- Evaluation of fungal deletion mutant strains for virulence attenuation.
- Nutritional supplementation to assess gene function.
Main Results:
- Egg infection outcomes were dose- and age-dependent and reproducible.
- Embryo susceptibility correlated with age and chemokine production.
- Pathological analysis suggested embryonic death due to invasion of membranes and blood vessels.
- Fungal mutant attenuation in the egg model mirrored that observed in murine models.
- Nutrient addition restored virulence in a specific mutant.
Conclusions:
- Embryonated eggs provide a viable, low-cost alternative infection model for Aspergillus species.
- This model effectively recapitulates virulence differences observed in mammalian studies.
- The egg model aids in reducing rodent usage for initial screening of fungal mutants.
