MYCOLab Ai Logo - gold and army green

Isolation and molecular identification of pathogens causing sea turtle egg fusariosis in key nesting beaches in Costa Rica

Summary

Scientists discovered that two harmful fungi, Fusarium falciforme and Fusarium keratoplasticum, are present on sea turtle nesting beaches across Costa Rica. These fungi can infect turtle eggs and cause high mortality rates in developing embryos. The researchers used advanced genetic techniques to accurately identify these pathogens and found them widespread at important nesting sites, highlighting the need for monitoring and protection strategies to prevent this emerging disease from becoming a major threat to sea turtle populations.

Background

Sea turtle egg fusariosis (STEF) is an emerging fungal disease caused by Fusarium falciforme and Fusarium keratoplasticum that threatens endangered sea turtle populations worldwide. The disease is associated with high embryo mortality rates and poses a significant conservation challenge. Previous identifications of STEF-causing species in Costa Rica relied on single-locus analyses, which may be insufficiently informative for accurate species discrimination.

Objective

To conduct the first comprehensive molecular identification of STEF-causing pathogens across four key sea turtle nesting beaches in Costa Rica using multilocus sequence typing (MLST). The study aimed to determine the presence, distribution, and species composition of Fusarium falciforme and Fusarium keratoplasticum at important nesting sites on both Pacific and Caribbean coasts.

Results

Of 147 fungal isolates, 47 (32%) belonged to STEF-causing species: Fusarium falciforme (n=32) and Fusarium keratoplasticum (n=15). Fusarium falciforme was detected at all study locations on both coasts, while F. keratoplasticum was exclusively found in failed leatherback eggs at Pacuare on the Caribbean coast. Additional Fusarium and other fungal species were also isolated, including Aspergillus species known to produce mycotoxins.

Conclusion

This study represents the first accurate survey documenting widespread presence of STEF-causing pathogens across Costa Rica’s main sea turtle nesting beaches using robust multilocus phylogenetic analysis. While STEF is not currently severely affecting sea turtles in Costa Rica, changes in nesting beach environment and sand composition could increase disease incidence and severity, necessitating monitoring and preventive conservation strategies.
  • Published in:PLoS One,
  • Study Type:Field survey with molecular analysis,
  • Source: PMID: 40997043, DOI: 10.1371/journal.pone.0333280
Scroll to Top