A 30-year-old woman suffers a tonic-clonic seizure and presents with delirium and hydrophobia. The patient states that she was bitten on the hand by a bat about 1 month ago. The patient subsequently dies of respiratory failure. Viral paicles are found throughout the brainstem and cerebellum at autopsy. In addition to direct viral cytotoxicity, the necrosis of virally infected neurons in this patient was mediated primarily by which of the following mechanisms?

**Core Concept**
The underlying principle being tested is the pathogenesis of viral encephalitis, specifically the mechanisms of neuronal injury and death in the context of viral infection. In this scenario, the patient is likely suffering from rabies, a viral disease transmitted through the saliva of infected animals, such as bats.

**Why the Correct Answer is Right**
The correct answer is related to the role of microglial activation and the subsequent release of pro-inflammatory cytokines and chemokines, which trigger an immune response that leads to neuronal injury and death. This mechanism is known as "antiviral-induced neuronal death" or "neuroinflammation-mediated neuronal death." In the context of rabies, the virus triggers an intense immune response in the central nervous system (CNS), leading to the activation of microglia and astrocytes, which release a variety of inflammatory mediators that contribute to neuronal injury and death.

**Why Each Wrong Option is Incorrect**
**Option A:** While apoptosis is a mechanism of neuronal injury in various diseases, it is not the primary mechanism of neuronal death in the context of rabies-induced encephalitis.

**Option B:** Necroptosis is a form of programmed necrosis that can be triggered by various stimuli, including viral infection. However, it is not the primary mechanism of neuronal death in rabies.

**Option C:** Autophagy is a cellular process that can be involved in the pathogenesis of various diseases, including viral infections. However, it is not the primary mechanism of neuronal death in rabies.

**Option D:** While excitotoxicity can contribute to neuronal injury in various diseases, it is not the primary mechanism of neuronal death in the context of rabies-induced encephalitis.

**Clinical Pearl / High-Yield Fact**
Rabies is a fatal disease if left untreated, and prompt post-exposure prophylaxis (PEP) is essential to prevent the development of the disease. The incubation period of rabies can range from a few days to several months or even years, and the disease can manifest with a variety of symptoms, including fever, headache, and hydrophobia.

**Correct Answer:** .

✓ Correct Answer: B. Humoral and cellular immunity