Experimental Rabies Infection of Non-nervous Tissues in Skunks (Mephitis mephitis) and Foxes (Vulpes vulpes)

Abstract

Abstract. Non-neural tissues, from three male and four female striped skunks (Mephitis mephitis), 5 to 7 months old, and one male and two female red foxes (Vulpes vulpes), 12 to 16 months old, experimentally infected with street rabies virus, were examined by light microscopic immunohistochemical and electron microscopic methods. This is the first report of ultrastructural lesions in rabies-infected adrenal medulla, cornea, and nasal glands. Using the streptavidin biotin peroxidase technique, antigen was detected in mucous cells and interstitial neurons and their processes in the submandibular salivary gland, in chromaffin cells of the adrenal medulla, in epidermal cells of the skin, in external root sheath cells of hair follicles, and in corneal epithelial cells. Electron microscopically, matrix (viral nucleocapsid), virions, and anomalous viral products were common in most tissues examined, but their relative proportions varied. The results suggested that replication with minimal accumulation of matrix and anomalous viral growth products was characteristic of growth in tissues (submandibular salivary gland) that frequently produce high titers of virus, whereas replication with large amounts of matrix and anomalous structures occurred in tissues (adrenal gland and nasal gland) that generally contained low or moderate titers of virus. Novel findings included viral budding into secretory granules, increase in microfilaments in infected mucogenic cells, and continuity of viral convoluted membranous profiles with rough endoplasmic reticulum of chromaffin cells and nasal glandular cells. The presence of viral antigen and developing virus in extra-neural tissues constitutes a potential risk of non-bite exposure to people in certain groups/occupations.

Rhabdovirus: Rabies

“…Multiple nonneural sites have also been associated with viral antigens following centrifugal transport from the CNS [ 62 ]. Studies suggest that the relative proportions of infectious virions will vary depending on the end organ examined [ 94 ]. Typical exit portal tissues important in transmission, such as salivary glands, support high viral titers and contain only a minimal accumulation of matrix and deviant viral production products, while multiplication in other nonneural sites, such as adrenal glands and mucous glands of the nasal mucosa, produce only moderate viral concentrations but large amounts of viral nucleocapsid and anomalous structures [ 94 ].…”

“…Studies suggest that the relative proportions of infectious virions will vary depending on the end organ examined [ 94 ]. Typical exit portal tissues important in transmission, such as salivary glands, support high viral titers and contain only a minimal accumulation of matrix and deviant viral production products, while multiplication in other nonneural sites, such as adrenal glands and mucous glands of the nasal mucosa, produce only moderate viral concentrations but large amounts of viral nucleocapsid and anomalous structures [ 94 ]. Further, antigens may be found in free sensory nerve endings of tactile hair in a skin biopsy, which is one of the best diagnostic methods of confi rming an antemortem diagnosis of rabies in humans [ 95 ].…”

A peep into detection of rabies in 20 th century

“…Similarly, ultra structural quantitative analysis of lesions in the sciatic nerves has been reported [59], which included 40% degeneration of myelinated axons with only occasional degeneration of unmyelinated axons. However, electron microscopy showed no typical bullet shaped virus particles.Electron microscopy has been used to study the rabies virus transport and infection of human dorsal root ganglia neurons [60].…”

Rabies: Epidemiology, Prevention, and Future Research

“…The known distribution of GT 2-6 is described from only a few isolates and, thus far, is confined to Africa, Europe, and the former Soviet Union. Fatal rabies-like human illnesses have been associated with several of these other lyssaviruses, including Mokola virus (GT 3), isolated from insectivores (Suncus), rodents, and domestic dogs and cats in East, West, and southern Africa (Familusi et al, 1972;Foggin, 1983 (Constantine, 1967 (Balachandran and Charlton, 1994). The nervous-tissue pathway of infection may shield the virus from the immune system, thus, accounting for the lack of early antibody response.…”