Histopathological and molecular characterization of encephalitic listeriosis in small ruminants from northern Paraná, Brazil

Abstract

Listeriosis is a disease primarily of ruminants caused by the Gram-positive bacterium Listeria monocytogenes. Ruminants either demonstrate manifestations of the encephalitic, septicemic, or reproductive form of listeriosis. The pathological and molecular findings with encephalitic listeriosis in a 5.5-month-old, male, mixed-breed goat and a 3-year-old Texel-crossed sheep from northern Paraná, Brazil are described. Clinically, the kid demonstrated circling, lateral protrusion of the tongue, head tilt, and convulsions; the ewe presented ataxia, motor incoordination, and lateral decumbency. Brainstem dysfunctions were diagnosed clinically and listeriosis was suspected. Necropsy performed on both animals did not reveal remarkable gross lesions; significant histopathological alterations were restricted to the brainstem (medulla oblongata; rhombencephalitis) and were characterized as meningoencephalitis that consisted of extensive mononuclear perivascular cuffings, neutrophilic and macrophagic microabscesses, and neuroparenchymal necrosis. PCR assay and direct sequencing, using genomic bacterial DNA derived from the brainstem of both animals, amplified the desired 174 base pairs length amplicon of the listeriolysin O gene of L. monocytogenes. Phylogenetic analyses demonstrated that the strains associated with rhombencephalitis during this study clustered with known strains of L. monocytogenes lineage I from diverse geographical locations and from cattle of the state of Paraná with encephalitic listeriosis. Consequently, these strains should be classified as L. monocytogenes lineage I. These results confirm the active participation of lineage I strains of L. monocytogenes in the etiopathogenesis of the brainstem dysfunctions observed during this study, probably represent the first characterization of small ruminant listeriosis by molecular techniques in Latin America, and suggest that ruminants within the state of Paraná were infected by the strains of the same lineage of L. monocytogenes.

Nervous form of listeriosis in buffaloes

“…In the present study, diagnosis of listeric meningoencephalitis was based on epidemiological data and on the pathological clinical condition of the animals, and was confirmed by immunostaining for Listeria monocytogenes. The histological changes observed in the buffaloes involved in the present outbreak are similar to those described in the literature in cattle and small ruminants (Oevermann et al 2010, Headley et al 2013.…”

“…The most significant lesions occurred in the brainstem, and were found unilaterally and characterized mainly by microabscesses, areas of malacia, and perivascular cuffs, similar to what has been observed in cattle (Sanches et al 2000, Oevermann et al , Margineda et al 2012, goats (Rissi et al 2006, Headley et al 2013, and sheep (Rissi et al 2010, Headley et al 2013.…”

What is your diagnosis? Cerebrospinal fluid from a goat

“…Listeria lesions have a characteristic affinity for the brainstem, are often unilateral, and are most severe in the medulla and pons with less pronounced severity seen rostrally and caudally to these sites. Neuroparenchymal microabscesses are the cardinal CNS lesions, with secondary extension involving the meninges . The gross and histopathologic findings, in this case, are consistent with those typically observed, except for the marked suppurative inflammation involving the meninges, ependyma, and ventricles, which are less common findings …”

Listeriosis in animals, its public health significance (food-borne zoonosis) and advances in diagnosis and control: a comprehensive review

“…It is primarily a disease of ruminants, particularly sheep, and causes encephalitis and abortion. In ruminants, it also produces syndromes of septicaemia, spinal myelitis, uveitis, gastroenteritis and mastitis (Rawool et al 2007;Headley et al 2014). The encephalitic form is known as 'circling disease' due to movement of the animal in circles in one direction (OIE 2014).…”