26.3 Acellular Diseases of the Nervous System
3 min read•june 18, 2024
Viruses and can wreak havoc on the nervous system. From to encephalitis, these pathogens cause inflammation and damage to vital brain and spinal cord tissues. The effects can be devastating, leading to symptoms like paralysis, seizures, and altered mental states.
are particularly insidious. These misfolded proteins corrupt normal proteins in the brain, causing spongiform changes and . With long incubation periods and no cure, prions pose unique challenges in diagnosis and treatment of fatal conditions like .
Viral Infections of the Nervous System
Types of nervous system viral infections
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- Meningitis: inflammation of the protective membranes covering the brain and spinal cord (meninges) caused by viruses such as (, ), (, ), and () leading to symptoms of headache, fever, stiff neck, photophobia, and altered mental status
- Encephalitis: inflammation of the brain tissue (parenchyma) caused by viruses such as herpesviruses (, VZV), (WNV, ), and resulting in fever, headache, altered mental status, seizures, and focal neurological deficits
- Some viruses exhibit , preferentially infecting nervous system tissues
- : inflammation of the spinal cord caused by viruses such as enteroviruses (), herpesviruses (VZV, ), and leading to weakness, sensory changes, and autonomic dysfunction
- : infection of the motor neurons (anterior horn cells) of the spinal cord caused by poliovirus (an enterovirus) characterized by fever, headache, stiff neck, and asymmetric
Comparison of arboviral encephalitis diseases
- West Nile virus (WNV)
- Transmission occurs through mosquito bites ()
- Symptoms include fever, headache, muscle pain (), and in severe cases, encephalitis or
- Treatment involves supportive care, as there is no specific antiviral therapy
- ()
- Transmission occurs through mosquito bites ( species)
- Symptoms are similar to WNV, but SLEV is more likely to cause encephalitis in older adults
- Treatment involves supportive care, as there is no specific antiviral therapy
- (JEV)
- Transmission occurs through mosquito bites (Culex species)
- Symptoms include fever, headache, vomiting, and in severe cases, encephalitis with high mortality rate
- Treatment involves supportive care, as there is no specific antiviral therapy; a vaccine is available for prevention
- () and ()
- Transmission occurs through mosquito bites (, , and Culex species)
- Symptoms include fever, headache, vomiting, and in severe cases, encephalitis with high mortality rate (especially for EEEV)
- Treatment involves supportive care, as there is no specific antiviral therapy
Viral neuroinvasion and neuropathogenesis
- Viruses can enter the nervous system through various routes, including:
- Hematogenous spread: viruses cross the
- Retrograde axonal transport: viruses travel along peripheral nerves
- Olfactory route: viruses enter through the nasal cavity
- can lead to direct cellular damage, inflammation, and disruption of normal neuronal function
Prion Diseases
Prions and spongiform encephalopathies
- Prions are misfolded proteins () that induce misfolding of normal proteins () in the brain leading to accumulation and neuronal degeneration, causing spongiform changes in the brain tissue
- Prions are unique infectious agents because they lack nucleic acids (DNA or RNA), are resistant to heat, chemicals, and radiation, have long incubation periods (months to years), and can be transmitted within a species and, in some cases, between species
- Examples of prion diseases include Creutzfeldt-Jakob disease (CJD) in humans, (BSE or "") in cattle, (CWD) in deer and elk, and scrapie in sheep and goats
- Transmission of prion diseases can occur through consumption of contaminated meat (variant CJD), exposure to contaminated surgical instruments or tissue grafts (iatrogenic CJD), or inherited mutations in the prion protein gene ()
- Symptoms of prion diseases include rapidly progressive , muscle jerks (), uncoordinated movements (), and behavioral changes
- Diagnosis is based on clinical presentation, MRI findings, and detection of PrPSc in brain tissue (postmortem)
- Treatment is supportive, as there is no effective cure for prion diseases
- Prion diseases are characterized by progressive neurodegeneration due to
Key Terms to Review (102)
Acetylcholine: Acetylcholine is a neurotransmitter that plays a crucial role in muscle contraction and the transmission of nerve impulses. It is vital for communication between neurons and muscles, affecting both the central and peripheral nervous systems.
Arboviral encephalitis: Arboviral encephalitis is an inflammation of the brain caused by arboviruses, which are transmitted by arthropods like mosquitoes and ticks. It can lead to severe neurological symptoms and potentially fatal outcomes.
Arboviruses: Arboviruses are a group of viruses transmitted by arthropod vectors such as mosquitoes and ticks. They can cause significant infections in the nervous system, leading to conditions like encephalitis or meningitis.
Arboviruses: Arboviruses, or arthropod-borne viruses, are a group of viruses that are transmitted by arthropod vectors, such as mosquitoes, ticks, and sandflies. These viruses primarily infect the nervous system and can cause a variety of neurological diseases in humans and animals.
Ataxia: Ataxia is a neurological condition characterized by a lack of muscle coordination, often resulting in unsteady movements, imbalance, and difficulty with voluntary movements. It is primarily associated with diseases or injuries affecting the nervous system, particularly the cerebellum, which is responsible for coordinating movement and balance.
Attenuated vaccine: An attenuated vaccine contains live pathogens that have been weakened so they cannot cause disease in healthy individuals. These vaccines stimulate a strong and lasting immune response.
Bacterial meningitis: Bacterial meningitis is an acute inflammation of the protective membranes covering the brain and spinal cord, known as the meninges. It is caused by bacterial infections and can be life-threatening if not treated promptly.
Blood-brain barrier: The blood-brain barrier (BBB) is a selective permeability barrier that separates the circulating blood from the brain and extracellular fluid in the central nervous system. It protects the brain from harmful substances while allowing essential nutrients to pass through.
Blood-Brain Barrier: The blood-brain barrier is a highly selective semipermeable membrane that separates the circulating blood from the brain and extracellular fluid in the central nervous system. It acts as a protective barrier, regulating the passage of substances between the bloodstream and the brain.
Bovine Spongiform Encephalopathy: Bovine spongiform encephalopathy (BSE), commonly known as 'mad cow disease', is a rare and fatal neurodegenerative disorder that affects cattle. It is classified as a prion disease, which are a group of progressive conditions that affect the structure and function of the brain and nervous system.
BSE Cattle: BSE, or Bovine Spongiform Encephalopathy, is a fatal neurodegenerative disease that affects cattle. It is an acellular disease of the nervous system, caused by abnormal prion proteins that lead to the development of sponge-like changes in the brain and spinal cord of infected animals.
C. tritaeniorhynchus: C. tritaeniorhynchus is a species of mosquito known for being a primary vector of the Japanese encephalitis virus (JEV), which can cause severe infections in the human nervous system. These mosquitoes are prevalent in rice-growing regions and are most active during the night.
Cannibalism: Cannibalism refers to the act of consuming the flesh or body parts of members of one's own species. In the context of acellular diseases of the nervous system, cannibalism is a key concept related to the transmission and propagation of these infectious agents.
Chronic wasting disease: Chronic wasting disease (CWD) is a fatal, transmissible spongiform encephalopathy affecting cervids like deer, elk, and moose. It is caused by misfolded prion proteins that lead to severe neurological degeneration.
Chronic Wasting Disease: Chronic Wasting Disease (CWD) is a fatal, neurodegenerative disease that affects certain species of deer, elk, and moose. It is classified as a transmissible spongiform encephalopathy, a group of rare, incurable diseases that cause the brain and nervous system to deteriorate over time.
CMV: CMV, or Cytomegalovirus, is a type of herpes virus that can cause serious infections in the nervous system. It is an acellular disease, meaning it does not require a host cell to replicate and can directly infect and damage cells in the nervous system, leading to various neurological complications.
Coquillettidia: Coquillettidia is a genus of mosquitoes that are known to transmit various acellular diseases affecting the nervous system. These mosquitoes are found in many parts of the world and play a crucial role in the epidemiology of these neurological disorders.
Coxsackievirus: Coxsackievirus is a type of enterovirus that can cause a variety of diseases, including neurological conditions affecting the central nervous system. These viruses are commonly associated with acellular diseases of the nervous system, such as viral meningitis and encephalitis.
Creutzfeldt-Jakob disease: Creutzfeldt-Jakob disease (CJD) is a rare, fatal neurodegenerative disorder caused by prions. It leads to rapidly progressive dementia and other neurological symptoms.
Culex: Culex is a genus of mosquitoes known for being vectors of several infectious diseases affecting humans. They are particularly significant in transmitting viruses that can lead to nervous system infections.
Culex species: Culex species are a genus of mosquitoes that are known to transmit several diseases, including acellular diseases of the nervous system. These mosquitoes are found worldwide and are vectors for various pathogens that can infect the human nervous system.
Culex tarsalis: Culex tarsalis is a species of mosquito known for transmitting various arboviruses, including those that can cause encephalitis. It plays a significant role in the spread of neuroinvasive diseases to humans.
Culiseta: Culiseta is a genus of mosquitoes that can serve as vectors for the transmission of certain neurological diseases, particularly those caused by acellular pathogens. These mosquitoes are known to play a role in the epidemiology of some nervous system disorders.
Dementia: Dementia is a general term that describes a decline in mental abilities severe enough to interfere with daily life. It is a group of symptoms associated with a progressive loss of memory, thinking, behavior, and social skills, often caused by damage or changes in the brain.
Eastern equine encephalitis (EEE): Eastern equine encephalitis (EEE) is a rare but severe viral infection of the brain caused by the Eastern equine encephalitis virus (EEEV). It is transmitted to humans and horses through the bite of an infected mosquito.
Eastern Equine Encephalitis Virus: The Eastern equine encephalitis virus is a rare but serious arbovirus that can cause a potentially fatal neurological illness in humans and horses. It is primarily transmitted by infected mosquitoes and primarily affects the central nervous system, leading to swelling of the brain (encephalitis).
Echovirus: Echovirus is a type of enterovirus that primarily infects the gastrointestinal tract and can cause a variety of illnesses, including meningitis, encephalitis, and other neurological disorders. These viruses are known for their ability to persist in the body and can reactivate, leading to recurrent infections.
EEEV: EEEV, or Eastern Equine Encephalitis Virus, is an acellular pathogen that primarily affects the nervous system. It is a single-stranded RNA virus that belongs to the genus Alphavirus and can cause a rare but severe and potentially fatal disease in humans and horses.
Emerson respirators: Emerson respirators are mechanical devices designed to assist or replace spontaneous breathing, crucial in managing severe respiratory infections that may affect the nervous system. Named after John H. Emerson, these respirators play a key role in treating patients with critical conditions like polio-induced respiratory paralysis.
Encephalopathy: Encephalopathy is a general term that refers to any disease or dysfunction of the brain, often characterized by altered mental state, impaired cognitive function, and neurological abnormalities. It can have various underlying causes, including infections, toxins, metabolic disorders, and structural brain damage.
Enteroviruses: Enteroviruses are a group of viruses that primarily infect the gastrointestinal tract and can spread to other parts of the body, including the nervous system. These viruses are known to cause a variety of diseases, including acute flaccid myelitis, a serious neurological condition.
False-negative: A false-negative result occurs when a test incorrectly indicates the absence of a condition or substance. This can lead to missed diagnoses and delayed treatments.
False-positive: A false-positive occurs when a test incorrectly indicates the presence of a condition, such as an infection or disease, when it is not actually present. This can lead to misdiagnosis and unnecessary treatment.
Familial CJD: Familial Creutzfeldt-Jakob disease (familial CJD) is a rare, inherited form of the neurodegenerative disorder Creutzfeldt-Jakob disease. It is caused by a genetic mutation that leads to the accumulation of abnormal prion proteins in the brain, ultimately resulting in progressive neurological symptoms and death.
Flaccid paralysis: Flaccid paralysis is a neurological condition characterized by weakness or loss of muscle tone without other obvious causes such as trauma. It often results from damage to motor neurons, leading to an inability for muscles to contract.
Glycine receptors: Glycine receptors are inhibitory neurotransmitter receptors located predominantly in the spinal cord and brainstem. They mediate synaptic inhibition by allowing chloride ions to enter neurons, causing hyperpolarization.
Herpes: Herpes refers to a group of viral diseases caused by the herpes simplex virus (HSV) types 1 and 2, leading to infections in various parts of the body, including the nervous system. These viruses are characterized by their ability to establish latent infections that can reactivate periodically.
Herpes simplex virus type 1 (HSV-1): Herpes simplex virus type 1 (HSV-1) is a contagious virus that predominantly causes oral herpes, leading to cold sores and fever blisters around the mouth. It can be transmitted through direct contact with infected saliva or lesions.
Herpesviruses: Herpesviruses are a group of DNA viruses that can establish lifelong latent infections in their hosts and reactivate periodically, causing recurrent disease. They are known for their ability to infect the nervous system and are associated with various acellular diseases affecting the nervous system.
HSV-1: HSV-1, or Herpes Simplex Virus Type 1, is a common viral infection that primarily affects the skin, mouth, and eyes. It is a member of the Herpesviridae family and is known for its ability to establish latent infections in the host's nervous system, leading to recurrent outbreaks.
HSV-2: HSV-2, or Herpes Simplex Virus Type 2, is a highly contagious virus that primarily causes genital herpes, a sexually transmitted infection (STI) affecting the genital and anal areas. It is one of the acellular diseases that can impact the nervous system.
Human rabies immune globulin: Human rabies immune globulin (HRIG) is a medication used for passive immunization against the rabies virus. It is administered after potential exposure to provide immediate but temporary protection until the rabies vaccine can stimulate active immunity.
Iatrogenic Transmission: Iatrogenic transmission refers to the unintentional spread of a disease or infection caused by medical procedures, treatments, or interventions. It occurs when healthcare providers inadvertently transmit pathogens to patients during the course of their medical care, often due to lapses in infection control practices.
Influenza: Influenza, commonly known as the flu, is a contagious respiratory illness caused by influenza viruses. It can lead to mild to severe illness and even death in extreme cases.
Iron lungs: Iron lungs are mechanical respirators used to assist breathing in patients with paralyzed respiratory muscles, commonly due to poliovirus infection. They function by creating negative pressure around the thoracic cavity to induce inhalation and exhalation.
Japanese encephalitis: Japanese encephalitis is a viral infection that affects the central nervous system, primarily spread by mosquitoes. It can lead to inflammation of the brain and severe neurological complications.
Japanese Encephalitis Virus: Japanese encephalitis virus (JEV) is a flavivirus that causes a potentially severe form of viral encephalitis, primarily affecting the central nervous system. It is one of the leading causes of viral encephalitis worldwide, particularly in Asia, and is considered an important acellular disease of the nervous system.
JEV: JEV, or Japanese Encephalitis Virus, is a member of the Flavivirus genus that primarily causes neurological infections in humans and animals. It is a significant public health concern, particularly in Asia, where it is one of the leading causes of viral encephalitis.
JEV is an acellular disease, meaning it does not require a host cell to replicate and can exist independently outside of a living organism. This unique characteristic allows the virus to persist in the environment and be transmitted through various means, posing a significant challenge in disease prevention and control.
Kuru: Kuru is a rare, fatal neurodegenerative disorder caused by prions, primarily affecting the Fore people of Papua New Guinea. It is transmitted through the practice of ritualistic cannibalism.
Kuru: Kuru is a rare, fatal, and incurable neurodegenerative disorder that primarily affects the nervous system. It is caused by infectious proteins called prions and is closely associated with the topics of viroids, virusoids, and acellular diseases of the nervous system.
Mad cow disease: Mad cow disease, or bovine spongiform encephalopathy (BSE), is a fatal neurodegenerative disease in cattle caused by prions. It leads to brain damage and is transmissible to humans as variant Creutzfeldt-Jakob disease (vCJD).
Meningitis: Meningitis is an inflammation of the protective membranes covering the brain and spinal cord, known as the meninges. It can be caused by various infectious agents, including bacteria, viruses, and fungi, and can have serious consequences if left untreated.
Meningoencephalitis: Meningoencephalitis is the inflammation of both the meninges and the brain tissue, often caused by infections such as bacteria, viruses, fungi, or parasites. It can lead to severe neurological damage and requires prompt medical attention.
Meningoencephalitis: Meningoencephalitis is a severe inflammation of the brain (encephalitis) and the membranes (meninges) that surround it. This condition can be caused by various infectious agents, including viruses, bacteria, fungi, and parasites, and can lead to significant neurological complications if not properly treated.
Microcephaly: Microcephaly is a medical condition where an infant's head is significantly smaller than expected, often due to abnormal brain development. It can be caused by various factors including genetic anomalies and infections during pregnancy.
Mumps: Mumps is a contagious viral infection characterized by the swelling of the parotid glands, which are salivary glands located near the ears. It can also cause complications in other parts of the body, including the nervous system and reproductive organs.
Myalgia: Myalgia is a medical term that refers to muscle pain or discomfort. It is a common symptom that can occur in various diseases and conditions affecting the nervous system, including acellular diseases covered in Chapter 26.3.
Myelitis: Myelitis refers to the inflammation of the spinal cord, which can lead to varying degrees of neurological impairment. This condition is often associated with viral infections, autoimmune diseases, or other infectious agents, resulting in symptoms such as pain, weakness, and sensory disturbances. Understanding myelitis is crucial in the context of acellular diseases of the nervous system, as it emphasizes the impact of non-cellular pathogens on neural tissues and their role in eliciting immune responses.
Myoclonus: Myoclonus is a sudden, brief, involuntary muscle jerk or twitch that can occur in various parts of the body. It is a common symptom associated with several neurological disorders and acellular diseases of the nervous system.
Negri bodies: Negri bodies are intracytoplasmic inclusions found in neurons, typically associated with rabies virus infection. They serve as a diagnostic marker for the disease.
Neurodegeneration: Neurodegeneration is the progressive loss of structure or function of neurons, including the death of neurons. It is a key feature of various neurological disorders, such as Alzheimer's disease, Parkinson's disease, and prion diseases, and can be caused by a variety of factors, including genetic mutations, environmental toxins, and infectious agents.
Neuroinvasion: Neuroinvasion refers to the ability of certain pathogens, such as bacteria, viruses, fungi, and parasites, to infiltrate and invade the nervous system, causing various neurological diseases and disorders. This process is a critical factor in understanding the pathogenesis and progression of many infectious diseases that target the central and peripheral nervous systems.
Neurotropism: Neurotropism refers to the ability of certain pathogens, such as viruses, bacteria, fungi, and parasites, to specifically target and infect the nervous system. These pathogens possess the unique capability to recognize, bind, and invade nerve cells, leading to various neurological diseases and disorders.
Pasteur: Louis Pasteur was a pioneering French microbiologist and chemist renowned for his discoveries in the principles of vaccination, microbial fermentation, and pasteurization. His work laid the foundation for modern microbiology and helped disprove the theory of spontaneous generation.
Polio vaccine: The polio vaccine is a biological preparation that provides immunity against poliomyelitis, an infectious disease caused by the poliovirus. It comes in two forms: inactivated poliovirus vaccine (IPV) and oral poliovirus vaccine (OPV).
Poliomyelitis: Poliomyelitis, also known as polio, is a highly contagious viral disease that primarily affects the nervous system, leading to muscle weakness and, in severe cases, paralysis. It is caused by the poliovirus, which can invade the central nervous system and damage the motor neurons responsible for muscle function.
Poliomyelitis (polio): Poliomyelitis (polio) is a highly infectious viral disease caused by the poliovirus, which primarily affects the nervous system and can lead to paralysis. The virus spreads through fecal-oral transmission or, less commonly, through contaminated water or food.
Poliovirus: Poliovirus is a highly contagious virus that primarily infects the gastrointestinal tract and can lead to the debilitating disease polio. It is a member of the Picornaviridae family and is the causative agent of the viral infection known as poliomyelitis.
Prion: A prion is an infectious agent composed primarily of a misfolded protein that can induce other, normally folded versions of the same protein to also misfold. Prions are responsible for a group of rare and fatal neurodegenerative disorders known as transmissible spongiform encephalopathies (TSEs).
Prion Diseases: Prion diseases are a group of rare, fatal neurodegenerative disorders caused by abnormally folded proteins called prions. These misfolded proteins can trigger the transformation of normal proteins into the same abnormal shape, leading to progressive damage and destruction of brain tissue.
Prions: Prions are infectious proteins that cause neurodegenerative diseases by inducing abnormal folding of normal cellular prion proteins, mainly in the brain. They lack nucleic acids and are resistant to standard methods of decontamination.
PRNP gene: The PRNP gene provides instructions for producing a protein called prion protein, which is found predominantly in the brain and nervous system. Mutations in the PRNP gene are associated with a group of rare, fatal neurodegenerative disorders known as prion diseases or transmissible spongiform encephalopathies (TSEs).
Protein Misfolding: Protein misfolding is a phenomenon where a protein fails to adopt its proper three-dimensional structure, leading to various pathological conditions, particularly in the nervous system. This term is crucial in understanding the context of acellular diseases of the nervous system.
PrP: PrP, or prion protein, is a unique type of infectious agent that is primarily composed of misfolded proteins, rather than genetic material like DNA or RNA. These misfolded prion proteins can induce other normally folded proteins to also misfold, leading to the development of progressive, fatal neurodegenerative diseases in both humans and animals.
PrPC: PrPC, or cellular prion protein, is a normal, naturally occurring protein found in the body, particularly in the central nervous system. It is the non-pathogenic, or non-disease-causing, form of the prion protein that is implicated in a group of rare, fatal neurodegenerative disorders known as transmissible spongiform encephalopathies (TSEs) or prion diseases.
PrPSc: PrPSc, or Scrapie Prion Protein, is the misfolded, infectious form of the normal cellular prion protein (PrPC) that is responsible for causing transmissible spongiform encephalopathies (TSEs), a group of rare and fatal neurodegenerative disorders affecting the nervous system.
Rabies: Rabies is a viral disease that causes acute inflammation of the brain in humans and other mammals. It is typically transmitted through the bite of an infected animal.
Rabies Virus: The rabies virus is a zoonotic virus that primarily infects the nervous system and causes a fatal neurological disease known as rabies. It is a member of the Lyssavirus genus and belongs to the Rhabdoviridae family of viruses.
Rabies virus (RV): Rabies virus (RV) is a neurotropic virus that causes rabies, a deadly infection of the central nervous system. It is typically transmitted through the bite of an infected animal.
Reverse transcriptase PCR (RT-PCR): Reverse transcriptase PCR (RT-PCR) is a laboratory technique used to amplify and detect RNA sequences by converting them into complementary DNA (cDNA) using reverse transcriptase. This method is essential for studying gene expression and detecting RNA viruses.
RT-QuIC: RT-QuIC, or real-time quaking-induced conversion, is a highly sensitive and specific diagnostic technique used to detect the presence of misfolded prion proteins in biological samples. It is a crucial tool in the study and diagnosis of acellular diseases affecting the nervous system.
Sabin vaccine: The Sabin vaccine, also known as the oral polio vaccine (OPV), is an attenuated vaccine used to prevent poliomyelitis. It contains live but weakened poliovirus strains of all three serotypes.
Salk vaccine: The Salk vaccine is an inactivated polio vaccine (IPV) that protects against poliomyelitis. Developed by Jonas Salk, it contains killed virus particles to stimulate an immune response without causing the disease.
Scrapie Agent: The scrapie agent is an infectious, acellular pathogen that causes a fatal neurodegenerative disease primarily affecting sheep and goats, known as scrapie. It is considered the prototype of a group of similar diseases called transmissible spongiform encephalopathies (TSEs) or prion diseases that can affect both animals and humans.
Scrapie Sheep: Scrapie is a fatal, neurodegenerative disease that affects sheep and goats. It is classified as a transmissible spongiform encephalopathy (TSE), a group of rare and incurable diseases that cause the brain and nervous system to deteriorate over time.
SLEV: SLEV, or St. Louis encephalitis virus, is an acellular virus that can cause a serious neurological disease known as St. Louis encephalitis. It is a member of the Flavivirus genus and is primarily transmitted to humans through the bite of infected mosquitoes, particularly Culex species. SLEV primarily affects the central nervous system and can lead to inflammation of the brain (encephalitis) and other neurological complications.
Slow Viruses: Slow viruses are a class of viruses that cause chronic, progressive diseases in the nervous system. Unlike acute viral infections, slow viruses have an extremely long incubation period, often taking years or even decades to produce symptoms and cause significant damage to the brain and other nervous system structures.
Spongiform Encephalopathy: Spongiform encephalopathy is a group of rare, fatal neurodegenerative disorders characterized by the formation of sponge-like holes in the brain tissue, leading to progressive neurological dysfunction and ultimately, death. These disorders are associated with the accumulation of abnormal prion proteins that cause the brain to degenerate in a sponge-like pattern.
St. Louis encephalitis (SLE): St. Louis encephalitis (SLE) is a viral disease that causes inflammation of the brain and is transmitted by mosquitoes. It predominantly affects individuals in North America, particularly in the United States.
St. Louis encephalitis virus: The St. Louis encephalitis virus is a single-stranded RNA virus that belongs to the genus Flavivirus and is the causative agent of St. Louis encephalitis, a rare but potentially serious neurological disease. It is primarily transmitted to humans through the bite of infected mosquitoes, particularly Culex mosquitoes, and can lead to inflammation of the brain, known as encephalitis.
Tonsillar Biopsy: A tonsillar biopsy is a medical procedure in which a small sample of tissue is taken from the tonsils for analysis. This procedure is often used to diagnose various conditions, including infections, tumors, or other abnormalities affecting the tonsils, which are lymphoid organs located at the back of the throat.
Transmissible spongiform encephalopathies (TSEs): Transmissible spongiform encephalopathies (TSEs) are a group of progressive, invariably fatal diseases characterized by spongy degeneration of the brain tissue. They are caused by prions, which are misfolded proteins that induce abnormal folding in normal cellular proteins.
Transmissible spongiform encephalopathy: Transmissible spongiform encephalopathy (TSE) is a group of progressive, fatal neurodegenerative diseases caused by prions. These diseases are characterized by brain tissue damage that leads to sponge-like holes in the brain.
Variant Creutzfeldt-Jakob Disease (vCJD): Variant Creutzfeldt-Jakob Disease (vCJD) is a rare and fatal neurodegenerative disorder that affects the brain and nervous system. It is a type of prion disease, caused by the accumulation of abnormal prion proteins, which leads to the destruction of brain tissue and the onset of progressive neurological symptoms.
vCJD is closely linked to the consumption of beef products contaminated with the agent that causes bovine spongiform encephalopathy (BSE), also known as 'mad cow disease.' The transmission of the BSE agent to humans is believed to be the primary cause of vCJD.
Viral meningitis: Viral meningitis is an inflammation of the protective membranes covering the brain and spinal cord, caused by viral infections. It is generally less severe than bacterial meningitis but can present similar symptoms.
VZV: VZV, or Varicella-zoster virus, is a member of the herpesvirus family that primarily causes two distinct diseases: varicella (chickenpox) and herpes zoster (shingles). This virus is an important acellular pathogen that can affect the nervous system, leading to various neurological complications.
WEEV: WEEV, or Western Equine Encephalitis Virus, is a member of the Alphavirus genus and is the causative agent of the acellular disease Western Equine Encephalitis (WEE). It is primarily transmitted through the bite of infected mosquitoes and can lead to potentially severe neurological complications in humans and horses.
West Nile encephalitis (WNE): West Nile encephalitis (WNE) is a viral infection of the brain caused by the West Nile virus, primarily transmitted through mosquito bites. It can lead to inflammation of the brain, which may result in severe neurological damage or death.
West Nile virus: West Nile virus is a mosquito-borne flavivirus that can cause a range of illnesses in humans, from mild flu-like symptoms to severe neurological conditions. It is primarily transmitted through the bite of infected mosquitoes and has become a significant public health concern due to its global spread and potential for serious health consequences.
Western equine encephalitis (WEE): Western equine encephalitis (WEE) is a mosquito-borne viral infection that affects the central nervous system, primarily in horses and humans. It is caused by the Western equine encephalitis virus (WEEV), an arbovirus of the Togaviridae family.
Western equine encephalitis virus: The Western equine encephalitis virus is a single-stranded RNA virus that belongs to the genus Alphavirus and is the causative agent of the neurological disease known as Western equine encephalitis. This virus is primarily transmitted to humans through the bite of infected mosquitoes and can lead to severe inflammation of the brain, spinal cord, and meninges, potentially resulting in long-term neurological complications or even death.
WNV: WNV, or West Nile Virus, is an acellular disease that primarily affects the nervous system. It is a flavivirus transmitted to humans through the bite of infected mosquitoes, leading to a range of neurological symptoms and potentially severe complications.