From models to medicine: systematic development and evaluation of animal models for Chlamydia psittaci respiratory and genital tract infections

Chlamydia psittaci ( C. psittaci ) is a zoonotic pathogen causing severe respiratory infections and systemic complications. Animal models are a crucial approach for studying C. psittaci . They can simulate the natural infection process and reveal the interaction between the host and the pathogen. This review examines the roles and limitations of various animal models in understanding the infection mechanism, developing vaccines and therapies, and researching the evolution and transmission of the pathogen. Mouse and guinea pig models are widely used in immunological research because they have numerous advantages in terms of genetic manipulation, cost-effectiveness, and operability. Poultry, which are natural hosts of C. psittaci , are of great significance for the study of the pathogenic characteristics and transmission routes of this pathogen in birds. Compared with small rodents, the immune systems of large mammals, such as non-human primates, are more complex. This is because they have a closer physiological relationship with humans and are the gold standard for evaluating treatment efficacy. Due to the significant disparities in standardized cross-model comparison data, future efforts should focus on the following aspects. (a) Establishing a unified evaluation framework to assess respiratory and reproductive tract infections. (b) Leveraging new technologies such as tissue organ models and humanized mice to eliminate species-specific differences. (c) Prioritizing the conduct of preclinical trials based on non-human primates to ultimately bridge the critical gap between basic research and the development of effective response measures.