Histopathology of Negri bodies in rabies encephalitis

Negri bodies are

eosinophilic Eosinophilic (Greek suffix -phil-, meaning ''loves eosin'') is the staining of tissues, cells, or organelles after they have been washed with eosin, a dye. Eosin is an acidic dye for staining cell cytoplasm, collagen, and muscle fibers. ''E ...

, sharply outlined,

pathognomonic Pathognomonic (rare synonym ''pathognomic'') is a term, often used in medicine, that means "characteristic for a particular disease". A pathognomonic sign is a particular sign whose presence means that a particular disease is present beyond any doub ...

inclusion bodies Inclusion bodies are aggregates of specific types of protein found in neurons, a number of tissue cells including red blood cells, bacteria, viruses, and plants. Inclusion bodies of aggregations of multiple proteins are also found in muscle cells ...

(2–10 μm in diameter) found in the

cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The ...

of certain

nerve cell A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa. No ...

s containing the virus of rabies, especially in pyramidal cells within

Ammon's horn The hippocampus (via Latin from Greek , 'seahorse') is a major component of the brain of humans and other vertebrates. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is part of the limbic system, an ...

of the

hippocampus The hippocampus (via Latin from Greek , 'seahorse') is a major component of the brain of humans and other vertebrates. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is part of the limbic system, a ...

. They are also often found in the

Purkinje cell Purkinje cells, or Purkinje neurons, are a class of GABAergic inhibitory neurons located in the cerebellum. They are named after their discoverer, Czech people, Czech anatomist Jan Evangelista Purkyně, who characterized the cells in 1839. Stru ...

s of the

cerebellar cortex The cerebellum (Latin for "little brain") is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as or even larger. In humans, the cerebe ...

from postmortem brain samples of

rabies Rabies is a viral disease that causes encephalitis in humans and other mammals. Early symptoms can include fever and tingling at the site of exposure. These symptoms are followed by one or more of the following symptoms: nausea, vomiting, vi ...

victims. They consist of ribonuclear proteins produced by the virus. They are named for

Adelchi Negri Adelchi Negri (16 July 1876 – 19 February 1912) was an Italian pathologist and microbiologist born in Perugia. He studied medicine and surgery at the University of Pavia, where he was a pupil of Camillo Golgi (1843–1926). After graduation ...

History and use as a Rabies Diagnosis

Adelchi Negri, an assistant pathologist working in the laboratory of

Camillo Golgi Camillo Golgi (; 7 July 184321 January 1926) was an Italian biologist and pathologist known for his works on the central nervous system. He studied medicine at the University of Pavia (where he later spent most of his professional career) betwee ...

, observed these inclusions in rabbits and dogs with

. These findings were presented in 1903 at a meeting of the Società Medico-Chirurgica of Pavia. The American pathologist Anna Wessels Williams made the same discovery, but because Negri published his results first, the bodies bear his name. Negri was convinced the inclusions were a parasitic protozoon and the

etiologic agent Cause, also known as etiology () and aetiology, is the Causality, reason or origination of something. The word ''etiology'' is derived from the Ancient Greek, Greek , ''aitiologia'', "giving a reason for" (, ''aitia'', "cause"; and , ''wikt:-logi ...

of rabies. Later that same year, however,

Paul Remlinger Paul Remlinger (29 December 1871 – 9 March 1964) was a French physician and biologist born in Bertrange, Moselle. He studied medicine at the Val de Grâce military hospital, supporting his doctoral thesis in 1893 at the University of Lyon w ...

and Rifat-Bey Frasheri in

Constantinople la, Constantinopolis ota, قسطنطينيه , alternate_name = Byzantion (earlier Greek name), Nova Roma ("New Rome"), Miklagard/Miklagarth (Old Norse), Tsargrad ( Slavic), Qustantiniya (Arabic), Basileuousa ("Queen of Cities"), Megalopolis (" ...

and, separately,

Alfonso di Vestea Alphons (Latinized ''Alphonsus'', ''Adelphonsus'', or ''Adefonsus'') is a male given name recorded from the 8th century (Alfonso I of Asturias, r. 739–757) in the Christian successor states of the Visigothic kingdom in the Iberian peninsula. ...

Naples Naples (; it, Napoli ; nap, Napule ), from grc, Νεάπολις, Neápolis, lit=new city. is the regional capital of Campania and the third-largest city of Italy, after Rome and Milan, with a population of 909,048 within the city's adminis ...

showed that the etiologic agent of rabies is a filterable

virus A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's 1 ...

. Negri continued until 1909 to try to prove that the intraneuronal inclusions named after him corresponded to steps in the developmental cycle of a protozoan. In spite of his incorrect etiologic hypothesis, Negri's discovery represented a breakthrough in the rapid diagnosis of rabies, and the detection of Negri bodies, using a method developed by Anna Wessels Williams, remained the primary way to detect rabies for the next thirty years.

References

External links

Slide at pathmicro.med.sc.edu – see bottom

See pathology video of Negri bodies
{{DEFAULTSORT:Negri Bodies Histopathology Rabies Hippocampus (brain) Neuropathology