Cerebral Toxoplasmosis in Striped Dolphins (Stenella coeruleoalba) Stranded Along the Ligurian Sea Coast of Italy

Abstract

This article reports the results of necropsy, parasitologic, microbiologic, histopathologic, immunohistochemical, indirect immunofluorescence, biomolecular, and serologic investigations on 8 striped dolphins (Stenella coeruleoalba) found stranded from August to December 2007 on the Ligurian Sea coast of Italy. Severe, nonsuppurative meningoencephalitis was found in 4 animals, as characterized by prominent perivascular mononuclear cell cuffing and macrophage accumulations in neuropil. These lesions were associated with mild lymphocytic-plasmacytic infiltration of choroid plexuses in 1 dolphin. Toxoplasma gondii cysts and zoites, confirmed by immunohistochemical labeling, were scattered throughout the brain parenchyma of 2 of the 4 dolphins. No viral inclusions were seen in the brain of any animal. Other findings included severe bronchointerstitial pneumonia and pulmonary atelectasis, consolidation, and emphysema. Parasites were identified in a variety of organs, including lung (Halocerchus lagenorhynchi). Microbiologic and serologic examinations for Brucella spp were negative on all 8 dolphins. The 4 animals with meningoencephalitis had serum antibodies against T gondii (titers ranging from 1:80 to 1:320) but not against morbillivirus. In contrast, the other 4 dolphins were seropositive for morbillivirus (with titers ranging from 1:10 to 1:40) but seronegative for T gondii. No morbillivirus antigen or nucleic acid was detected in the tissues of any dolphin. It is concluded that the severe lung and brain lesions were the cause of death and that T gondii was the likely etiologic agent of the cerebral lesions. Morbillivirus infection was not considered to have contributed to death of these animals.

Meningoencephalitis and Listeria monocytogenes, Toxoplasma gondii and Brucella spp. coinfection in a dolphin in Italy

“…In the cerebral cortex, scattered protozoan cysts surrounded by glial nodules and mononuclear cell aggregates were also observed. Presence of Toxoplasma gondii cysts was confirmed by IHC (Di Guardo et al 2010; Fig. 1D), while IHC labelling for Listeria monocytogenes and morbillivirus, performed with polyclonal (Dell 'Armelina Rocha et al 2013) and monoclonal (Di Guardo et al 2010) antibodies, respectively, did not demonstrate any antigen.…”

“…Presence of Toxoplasma gondii cysts was confirmed by IHC (Di Guardo et al 2010; Fig. 1D), while IHC labelling for Listeria monocytogenes and morbillivirus, performed with polyclonal (Dell 'Armelina Rocha et al 2013) and monoclonal (Di Guardo et al 2010) antibodies, respectively, did not demonstrate any antigen. The liver had multifocal necrosis and moderate chronic cholangiohepatitis (Fig.…”

“…Toxoplasma gondii meningoencephalitis has been reported in odontocetes (Di Guardo et al 2010), having been also detected in Brucella ceti-coinfected striped dolphins (González et al 2002, Alba et al 2013). Here we describe the first case of neurolisteriosis due to L. monocytogenes associated with T. gondii and Brucella spp.…”

Retrospective Study of Etiologic Agents Associated with Nonsuppurative Meningoencephalitis in Stranded Cetaceans in the Canary Islands

“…gondii, an apicomplexan protozoan parasite, infects a range of hosts worldwide, including several marine mammal species, in which it may cause abortion, lethal systemic disease (14), and nonsuppurative (NS) encephalitis (15)(16)(17)(18).…”

Toxoplasma gondii in stranded marine mammals from the North Sea and Eastern Atlantic Ocean: Findings and diagnostic difficulties

“…coeruleoalba) (Di Guardo et al, 2010;Grattarola et al, 2016), and with morbillivirus in fin whales (Balaenoptera physalus) (Mazzariol et al, 2012). Additionally, research on T. gondii in marine mammals is relevant as T. gondii acts as an indicator for marine pollution and marine mammals are sentinel species for the health of the marine ecosystems they live in (de Moura et al, 2014;Gibson et al, 2011;Moore, 2008).…”