A 12-year-old boy develops fever, accompanied by occasional headaches, malaise, fatigue, and nausea a month after being bitten by a dog. One day later, he experiences episodes of rigidity, hallucinations, breath-holding, and difficulty swallowing because of uncontrollable oral secretions. Dr. Louis Pasteur is consulted. He writes: "The death of this child appearing to be inevitable, I decided, not without lively and sore anxiety, as may well be believed, to try ....... the method which I had found constantly successful with dogs. Consequently, 60 hours after the bites was inoculated under a fold of skin with half a syringeful of the spinal cord of a rabbit. In the following days, fresh inoculations were made. I thus made 13 inoculations." The boy survives. Which of the following histologic findings in the brain of the dog is most likely to be present?
The child had rabies, an infectious disease in which the virus travels from the site of an infected animal bite up nerves to the CNS. Pathognomonic Negri bodies are cytoplasmic inclusions found in the hippocampal pyramidal cells and cerebellar Purkinje cells. Worldwide, unvaccinated dogs remain the most common vector for transmission of this bullet-shaped virus to man. The suspected animal must be sacrificed to identify the virus in the brain. Infected neurons generally do not undergo cell death; instead, the virus induces neurotoxin production that affects surface receptor interaction with neurotransmitters. After symptoms develop, survival is rare. Multinucleated cells may be seen in microglial nodules associated with HIV infection. Perivascular lymphocytic infiltrates are often seen with a variety of viruses, such as arboviruses or echoviruses, causing encephalitis. Toxoplasma gondii infection is characterized by finding enlarged, infected cells filled with bradyzoites. Spongiform change is characteristic of prion disease.
Multinucleate giant cells
Negri bodies
Perivascular lymphocytes
Pseudocysts with bradyzoites
Central Nervous System