Babesia: a world emerging.

Area of Science:

• Veterinary Parasitology
• Molecular Taxonomy
• Evolutionary Biology

Background:

• Babesia are tick-transmitted protozoa with significant veterinary and public health impacts.
• Diverse vertebrate hosts are susceptible, posing challenges for disease control.
• Classical taxonomy of Babesia is complex and requires molecular updates.

Purpose of the Study:

• To provide a comprehensive overview and revised molecular classification of Babesia species.
• To explore the evolutionary history of piroplasmids in relation to ticks and hosts.
• To discuss implications for understanding Babesia pathogenicity, drug resistance, and vaccine development.

Main Methods:

• Phylogenetic analyses using 18S rRNA and hsp70 genes.
• Generation of phylogenetic trees for molecular classification.
• Comparison of molecular data with classical taxonomic criteria.

Main Results:

• A revised molecular classification identifies five monophyletic Babesia lineages, one Cytauxzoon clade, and one Theileria clade.
• Phylogenetic data suggest piroplasmid evolution is linked to tick origins, predating mammalian radiation.
• Evidence points to potentially unknown piroplasmid lineages in reptiles and amphibians.

Conclusions:

• The revised molecular classification provides a framework for future Babesia research.
• The evolutionary hypothesis suggests ancient piroplasmid diversity in vertebrates.
• Understanding population genetics is crucial for addressing drug resistance and developing effective vaccines.