What Do We Know About Cryptococcus spp. in Portugal? One Health Systematic Review in a Comprehensive 13-Year...

Cryptococcosis, caused by the Cryptococcus neoformans and Cryptococcus gattii species complexes (pathogenic Cryptococcus spp.), is an environmentally acquired mycosis of One Health relevance. This study integrates a PRISMA-compliant systematic review (2000-2025) of Portuguese animal, human, and environmental reports with a 13-year retrospective dataset of laboratory-confirmed veterinary cryptococcosis cases (2013-2025). Clinical specimens were cultured and identified by MALDI-TOF mass spectrometry, and associations were assessed using χ² and Fisher's exact tests. Of 1059 submissions, 48 (4.5%) were culture-positive: 6.8% of canine, 5.3% of feline samples, and 4.0% of avian samples, with no detections in other vertebrate groups (p = 0.705). Cryptococcus neoformans predominated in carnivores (73.7%), while Papiliotrema laurentii (formerly Cryptococcus laurentii) was most frequent in birds (86.2%). Infection was not associated with sex or age. Seasonality was evident, with a July peak and summer predominance (p = 0.010). Most cases were from the Centre region (62.5%), with significant regional variation of Cryptococcus spp. distribution (p < 0.001). The systematic review confirmed autochthonous C. gattii complex disease and widespread C. neoformans contamination in pigeon guano and arboreal niches. These findings demonstrate a compartmentalised eco-epidemiology, reinforcing the need for integrated molecular typing, antifungal susceptibility testing, and coordinated human-animal-environment surveillance to inform targeted prevention and control strategies in Portugal.