Dear MARMAM community, My co-authors and I are pleased to share our latest book chapter about brucellosis in aquatic mammals. Vargas-Castro, I., Hernández-Mora, G., González-Barrientos, R., & Grattarola, C. (2025). *Brucellosis in aquatic mammals*. In *Brucellosis. **The Silent Threat to Livestock and Human Health* (pp. 133-145). Academic Press. https://doi.org/10.1016/B978-0-443-30067-7.00008-5 *Abstract*: The study of brucellosis in marine mammals has become crucial due to its zoonotic risks and its effects on marine species. The bacteria *Brucella ceti* and *Brucella pinnipedialis *cause significant health issues in cetaceans and pinnipeds, respectively. While *B. ceti* is associated with severe conditions and strandings, *B. pinnipedialis* often remains asymptomatic, though some cases of disease have been noted. The zoonotic potential of marine *Brucella* strains, particularly sequence type 27, further emphasizes the need for continuous surveillance and research. While real-time PCR is useful for detecting *Brucella* DNA, it faces limitations, making it unsuitable for direct application to these samples. Bacterial culture remains the gold standard for diagnosing brucellosis, and molecular techniques should be applied to these cultures to ensure accurate strain identification. Additionally, the limitation of standardized serological tests for all marine mammals species underscores the necessity for developing reliable and accesible diagnostic tools, including ELISAs, to improve diagnostic accuracy. Please do not hesitate to contact us for any questions you may have. Kind regards, *Ignacio Vargas Castro *[image: https://orcid.org/0000-0002-8721-3150] <https://orcid.org/0000-0002-8721-3150> DVM, PhD Viral Immunology and Preventive Medicine Unit (SUAT) VISAVET Health Surveillance Centre & Animal Health Department Universidad Complutense Madrid Av. Puerta de Hierro, s/n. 28040 Madrid. Spainignavarg@ucm.eswww.sanidadanimal.info <https://www.sanidadanimal.info/en/> This message is private and confidential and it is intended exclusively for the addressee. If you receive this message by mistake, you should not disseminate, distribute or copy this e-mail. Please inform the sender and delete the message and attachments from your system, as it is completely forbidden for you to use this information, according to the current legislation. No confidentiality nor any privilege regarding the information is waived or lost by any mistransmission or malfunction. The personal data herein will be collected in the file "Correoweb", under the ownership of the Vice-Rectorate for Information Technologies, in which those interested may exercise their right to access, rectify, erasure or right to object the contents (article 15-21 of Regulation (EU) 2016/679, General Data Protection Regulation). Before printing this mail please consider whether it is really necessary: the environment is a concern for us all.