CASE REPORT: Neurobrucellosis in a common bottlenose dolphin

7 September 2020 – News

Since the first description of Brucellosis in marine mammals in 1994, reported cases in cetaceans and pinnipeds have been increasing. While the disease has been seen in various cetaceans, pathological findings are unusual and cases of damage to the nervous system have been largely confined to striped dolphins (Stenella coeruleoalba).

This is the first reported case of neurobrucellosis in a common bottlenose dolphin (Tursiops truncatus) from the Canary Islands. Until now the pathological signs noted in this species had been blubber and lung abscesses, discospondylitis, vertebral osteomyelitis, placentitis, abortion and parasitic pneumonia. This juvenile female presented differently.

The animal was found stranded in Lanzarote and died soon after. On examination, a parasitic infestation was evident in various locations. The cerebral leptomeninges were also thickened and congested and the shoulder joints showed bilateral arthritis. Microscopic lesions were compatible with Cetacean Morbillivirus (CeMV), the most pathogenic virus threatening dolphins and whales worldwide. However, despite the histopathological identification of severe non-suppurative meningitis, encephalomyelitis and perineuritis in the CNS, morbillivirus was only detected in some areas, which supported the existence of a co-infection pathogen. Brucella spp. was then detected by immunochemistry in the CNS and in the shoulder joint.

Few cases of these pathogens co-infecting a host have been reported so far and whether there is an interaction between them is not known. It is also unclear how this animal came to be infected. It has been suggested that fish or helminth may function as reservoirs.

The zoonotic potential of Brucella ceti, particularly the strain ST27, should not be overlooked as at least four human cases of acquired infection from marine mammals have been reported. Special precautions should be taken when rescuing, rehabilitating or necropsying these marine species.

Sierra et al. Neurobrucellosis in a common bottlenose dolphin (Tursiops truncatus) stranded in the Canary Islands. BMC Veterinary Research (2019) 15:353 ttps://doi.org/10.1186/s12917-019-2089-0