Leptospiral meningoencephalitis in a raccoon dog

Abstract

Neuroleptospirosis is a rare disease caused by pathogenic Leptospira interrogans in humans; however, it has not been fully studied in animals. A young wild raccoon dog was found convulsing in the recumbent position and died the next day. Histologic examination revealed nonsuppurative meningoencephalitis in the cerebrum, cerebellum, midbrain, and medulla oblongata. The lesions consisted of mixed infiltrates of Iba1-positive macrophages and CD3-positive T cells, with a small number of CD79α-positive B cells and myeloperoxidase-positive neutrophils. In the frontal cortex, perivascular cuffs and adjacent microglial nodules were distributed diffusely, especially in the molecular layer. Glial nodules were comprised of Iba1- and myeloperoxidase-positive activated microglia. Immunohistochemistry revealed leptospires in mononuclear cell perivascular cuffs, but not in glial nodules. Neuroleptospirosis was accompanied by Leptospira-related nonsuppurative interstitial nephritis, pulmonary edema and hemorrhage, and coronary periarteritis, as well as Toxocara tanuki in the small intestine and nonspecific foreign-body granulomas in the lungs and stomach.

Vector-Borne and Zoonotic Pathogens in Raccoon Dogs (Nyctereutes procyonoides) and Raccoons (Procyon lotor) from Schleswig-Holstein, Germany

“…Raccoon dogs and raccoons have the potential of being competent reservoirs of various pathogens, including rodent-borne and arthropod-borne pathogens [ 5 , 8 , 15 , 17 , 18 ]; however, there is a lack of data on the reservoir function of these neozoa in northern Germany.…”

“…Until now, Leptospira spp. were only identified in Korean raccoon dog faeces [ 62 ] and a brief report on leptospiral meningoencephalitis in a Japanese raccoon dog has been published [ 18 ]. The prevalence of Leptospira spp.…”

“…focal or diffuse interstitial nephritis and acute transient tubular injury or tubular epithelial necrosis [ 61 ] in the kidneys of 90.5% of the infected raccoon dogs. Nevertheless, raccoon dogs are susceptible to disease, as in a raccoon dog from Japan leptospiral mengingoencephalitis was diagnosed with the histologic sections of the kidneys revealing diffuse lymphoplasmacytic interstitial nephritis [ 18 ]. Raccoons are also susceptible to disease and may not only serve as asymptomatic reservoirs, as interstitial nephritis was found histologically in raccoons originating from Germany, including in the present study and in the USA [ 52 , 69 ].…”

“…and Rickettsia spp. [ 5 , 8 , 15 , 17 , 18 ]. Their host and vector potential allows pathogens to increase in the environment and to extend their geographical range [ 5 , 9 , 15 , 19 , 20 ].…”