Babesiosis is a potentially very serious infection, but too little known. investigators want to raise their clinical colleagues and remind fellow biologists of the importance of choosing a good molecular diagnosis so as not to give false-negative results.

Inclusion criteria:

• Major subject (≥18 years old)
• Splenectomized subject
• Subject with severe babesiosis
• Subject not having expressed, after information, his opposition to the reuse of his data for the purposes of this research

Exclusion criteria:

- Subject having expressed opposition to participating in the study

Major subject suffering from severe babesiosis