Early-life Giardia Infection and Behavioral Dysregulation in Two Dogs: A Case-Based Exploration of the Gut-Brain Axis

Abstract

This case report describes two dogs exhibiting severe behavioural problems, both diagnosed with early-life giardiasis and raised in environments lacking adequate maternal care and socialisation. Both dogs experienced chronic gastrointestinal and dermatological issues, as well as prolonged early-life stress, which likely contributed to heightened arousal and insecure behavioural patterns. The combination of giardiasis and adverse early-life conditions may have interacted to affect gut microbiome–brain axis communication and exacerbate behavioural dysregulation during critical developmental periods. These cases highlight the complex interplay between infection, early adverse internal and external stimuli, and behavioural development, emphasising the need for integrated medical and behavioural interventions in high-risk dogs. Further research is needed to clarify causal relationships and the role of gut microbiota in behavioural regulation.