Systematic Analysis of Virtopsy Findings of Brucella ceti Infection in Cetaceans Using Post-mortem Computed Tomography (PMCT)

Participant(s)

Activity date	11 Jun 2021
Degree of recognition	International

Description

Brucellosis is a bacterial disease that affects both terrestrial and marine mammals. Brucella ceti causes brucellosis in multiple cetacean families including Delphinidae, Phocoenidae, Balaenopteridae, Ziphidae, and Physiteridae and has been increasingly reported worldwide.1,2 Brucellosis in cetaceans is associated with reproductive failure in males and females, meningoencephalitis, spinal discospondylitis, subcutaneous abscesses, among other pathological conditions.3,4,5 Isolation of the bacterium from infected organs or body fluids is required to attain a confirmatory diagnosis. Sample selection may vary depending on the clinical presentation of brucellosis in the affected animal. In marine mammals, ideal samples collected at postmorterm examination include cerebrospinal fluid, brain, reproductive organs and fluids, placenta, milk, lymph nodes, and lungs, which reflect the higher frequency of neurological and reproductive signs described in cetaceans with brucellosis.6,7,8,9 Besides isolation, brucellosis diagnostic techniques include serologic tests, conventional necropsy, histopathology, immunohistochemistry, and molecular identification methods.10 Nonetheless, diagnostic imaging techniques such as postmortem computed tomography (PMCT) are rarely utilized to aid the diagnosis of this lethal bacterial disease in stranded cetaceans. The aim of this study was to investigate the applicability of the pioneering use of virtopsy (virtual necropsy) as a complementary tool to diagnose Brucellosis in stranded cetaceans. Pathological findings of brucellosis in stranded cetaceans of the Pacific coast of Costa Rica were documented for the first time using PMCT. Special emphasis was given to postmortem findings of neurobrucellosis, establishing unique criteria for the diagnosis of brucella-related hydrocephalus and meningoencephalitis in stranded cetaceans based on the computed tomography (CT) criteria already established in human medicine. This study will aid the understanding of the pathology of brucellosis in cetaceans and will be able to provide a detailed postmortem diagnostic imagining reference guide for marine mammal veterinarians working with live or stranded specimens from which brucellosis is suspected. Our results will enhance the knowledge of bacterial infection mechanisms in stranded cetaceans, supplementing conventional necropsy for a better insight into cause of death with radiological pathology investigations.

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