Diagnosis
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| Viliuisk encephalomyelitis | |
|---|---|
| Specialty | Neurological |
Viliuisk Encephalomyelitis (VE) is a fatal progressive neurological disorder found only in the Sakha (Iakut/Yakut) population of central Siberia. [1] [2] About 15 new cases are reported each year. VE is a very rare disease and little research has been conducted. The causative agents, origin of the disease, and involved candidate genes are currently unknown, but much research has been done in pursuit of the answers. Those inflicted with the disease survive for a period of only a few months to several years. VE follows three main courses of infection: an acute form, a sub-acute form subsiding into a progressive form, and a chronic form. Initially, the infected patients experience symptoms such as: severe headaches, delirium, lethargy, meningism, bradykinesia, and incoordination. [1] A small percentage of patients die during the acute phase as result of a severe coma. In all cases the disease is fatal.
As of 2007, fewer than 500 Yakut individuals have been infected with VE. [3] Viliuisk Encephalomyelitis is classified as a progressive neurological disorder that ultimately ends in the death of the infected individual. The disease has three distinguishable phases: The acute form, the progressive form, and the chronic form.[ citation needed ]
The acute form is the most rapid and most violent of all the stages. It begins with the characteristic rigidity of the muscles, accompanied by slurred speech, severe headaches, and exaggeration of cold-like symptoms. Patients usually die within weeks of the initial symptoms. Routine post-mortem examinations yield: severe inflammation of the brain lining, clusters of dead cells and tissue, and largely increased amounts of macrophages and lymphocytes. [3] [4]
The progressive form is the most common case. Patients initially experience acute-like symptoms which are not as severe, and subside within a few weeks. Following the sub-acute phase, the patients experience a few mild symptoms including some behavioral changes, incoordination, and difficulty in speech. Eventually the disease developed fully and those infected were stricken with the characteristic symptoms of rigidity, slurred speech, and deterioration of cognitive functions. [3] [4] Ultimately, brain function depreciates rapidly resulting in death.[ citation needed ]
Many patients who undergo the chronic form claim never to have had an acute attack. These patients endure varying measures of impairment and suffer mental deterioration for the remainder of their lives. Usually they live to be very old and succumb to other diseases. [3] [4]
In almost all cases there are changes characteristic of VE. Early onset shows an increased number of lymphocytes and increased protein concentration — which reduces over many years. These factors help neurologists determine the form of VE based on progression. The trademark changes in the brain include: thickened inflamed meninges, necrotic cortical lesions, increased number of lymphocytes, and neuronal death. [3] [5]
Currently the mechanism of spread and infection is unknown despite the tedious epidemiological, clinical, and neurological studies that have been conducted. [6] Recent Studies show Horizontal Disease Transmission, or the transmission of a disease from one individual to another of the same generation. It appears that VE is an infectious disease; however, the incubation period would have to be very extensive [1] (in excess of 5 years). Many infected individuals attribute the initial symptoms as a result of a plunge in frigid waters. So far, no causative agent has been found in blood, spinal fluid, or brain tissue. [1] [7]
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Research has concluded that VE has been present in the Viuli valley for many centuries among the Evenk populations of northern Siberia. [1] [8] The disease had its debut through its first Yakut diagnosis a little over a century ago in villages of the Viuli region of Siberia. Not until after World War II did the Yakut people become aware of this mysterious killer. The locals and Northern Evenks referred to this illness as “Bokhoror” or “the stiffness” because of the typical rigidity of the limbs those infected individuals experienced. Viliuisk Encephalomyelitis is currently isolated in the Yakut (Sakha) populations of Siberia, Russia. However, extensive migration might allow the disease to become a continental epidemic as it has already spread the infection radius many miles since its induction in the early 1900s. [1]
Fifty years ago it was believed that the Yakut people had extremely degraded immune systems as result of malnourishment and starvation from the World War. It was believed that this disease was docile and those with healthy immune systems could easily fight it off. This inclination appeared to be accurate until a case of a single Caucasian Russian woman. Supposedly, she infected herself as a means to end her own life. She injected herself with cerebrospinal fluid of a victim of VE, and died as a result of it. This is the first and only reported infection and death of a Caucasian.[ citation needed ]
Acute disseminated encephalomyelitis (ADEM), or acute demyelinating encephalomyelitis, is a rare autoimmune disease marked by a sudden, widespread attack of inflammation in the brain and spinal cord. As well as causing the brain and spinal cord to become inflamed, ADEM also attacks the nerves of the central nervous system and damages their myelin insulation, which, as a result, destroys the white matter. It is often triggered by a viral infection or vaccinations.
Transverse myelitis (TM) is a rare neurological condition in which the spinal cord is inflamed. Transverse implies that the inflammation extends horizontally across the spinal cord. Partial transverse myelitis and partial myelitis are terms sometimes used to specify inflammation that only affects part of the width of the spinal cord. TM is characterized by weakness and numbness of the limbs, deficits in sensation and motor skills, dysfunctional urethral and anal sphincter activities, and dysfunction of the autonomic nervous system that can lead to episodes of high blood pressure. Signs and symptoms vary according to the affected level of the spinal cord. The underlying cause of TM is unknown. The spinal cord inflammation seen in TM has been associated with various infections, immune system disorders, or damage to nerve fibres, by loss of myelin. As opposed to leukomyelitis which affects only the white matter, it affects the entire cross-section of the spinal cord. Decreased electrical conductivity in the nervous system can result.
Canine distemper virus (CDV) is a viral disease that affects a wide variety of mammal families, including domestic and wild species of dogs, coyotes, foxes, pandas, wolves, ferrets, skunks, raccoons, and felines, as well as pinnipeds, some primates, and a variety of other species. CDV does not affect humans.
Myelitis is inflammation of the spinal cord which can disrupt the normal responses from the brain to the rest of the body, and from the rest of the body to the brain. Inflammation in the spinal cord, can cause the myelin and axon to be damaged resulting in symptoms such as paralysis and sensory loss. Myelitis is classified to several categories depending on the area or the cause of the lesion; however, any inflammatory attack on the spinal cord is often referred to as transverse myelitis.
Psittacosis—also known as parrot fever, and ornithosis—is a zoonotic infectious disease in humans caused by a bacterium called Chlamydia psittaci and contracted from infected parrots, such as macaws, cockatiels, and budgerigars, and from pigeons, sparrows, ducks, hens, gulls and many other species of birds. The incidence of infection in canaries and finches is believed to be lower than in psittacine birds.
Encephalomyelitis is inflammation of the brain and spinal cord. Various types of encephalomyelitis include:
California encephalitis orthobunyavirus type strain California encephalitis virus was discovered in Kern County, California, and causes encephalitis in humans. Encephalitis is an acute inflammation of the brain that can cause minor symptoms, such as headaches, to more severe symptoms such as seizures. Mosquitoes serve as its carrier and for this reason this virus is known as an arbovirus.
Subacute sclerosing panencephalitis (SSPE)—also known as Dawson disease—is a rare form of chronic, progressive brain inflammation caused by slow infection with certain defective strains of hypermutated measles virus. The condition primarily affects children, teens, and young adults. It has been estimated that about 2 in 10,000 people who get measles will eventually develop SSPE. However, a 2016 study estimated that the rate for unvaccinated infants under 15 months was as high as 1 in 609. No cure for SSPE exists, and the condition is almost always fatal. SSPE should not be confused with acute disseminated encephalomyelitis, which can also be caused by the measles virus, but has a very different timing and course.
Viral encephalitis is inflammation of the brain parenchyma, called encephalitis, by a virus. The different forms of viral encephalitis are called viral encephalitides. It is the most common type of encephalitis and often occurs with viral meningitis. Encephalitic viruses first cause infection and replicate outside of the central nervous system (CNS), most reaching the CNS through the circulatory system and a minority from nerve endings toward the CNS. Once in the brain, the virus and the host's inflammatory response disrupt neural function, leading to illness and complications, many of which frequently are neurological in nature, such as impaired motor skills and altered behavior.
Experimental autoimmune encephalomyelitis, sometimes experimental allergic encephalomyelitis (EAE) is an animal model of brain inflammation. It is an inflammatory demyelinating disease of the central nervous system (CNS). It is mostly used with rodents and is widely studied as an animal model of the human CNS demyelinating diseases, including multiple sclerosis (MS) and acute disseminated encephalomyelitis (ADEM). EAE is also the prototype for T-cell-mediated autoimmune disease in general.
Meningoencephalitis, also known as herpes meningoencephalitis, is a medical condition that simultaneously resembles both meningitis, which is an infection or inflammation of the meninges, and encephalitis, which is an infection or inflammation of the brain.
Granulomatous meningoencephalitis (GME) is an inflammatory disease of the central nervous system (CNS) of dogs and, rarely, cats. It is a form of meningoencephalitis. GME is likely second only to encephalitis caused by canine distemper virus as the most common cause of inflammatory disease of the canine CNS. The disease is more common in female dogs of young and middle age. It has a rapid onset. The lesions of GME exist mainly in the white matter of the cerebrum, brainstem, cerebellum, and spinal cord. The cause is only known to be noninfectious and is considered at this time to be idiopathic. Because lesions resemble those seen in allergic meningoencephalitis, GME is thought to have an immune-mediated cause, but it is also thought that the disease may be based on an abnormal response to an infectious agent. One study searched for viral DNA from canine herpesvirus, canine adenovirus, and canine parvovirus in brain tissue from dogs with GME, necrotizing meningoencephalitis, and necrotizing leukoencephalitis, but failed to find any.
Kuru is a rare, incurable, and fatal neurodegenerative disorder that was formerly common among the Fore people of Papua New Guinea. Kuru is a form of transmissible spongiform encephalopathy (TSE) caused by the transmission of abnormally folded proteins (prions), which leads to symptoms such as tremors and loss of coordination from neurodegeneration.
Neuroborreliosis is a disorder of the central nervous system. A neurological manifestation of Lyme disease, neuroborreliosis is caused by a systemic infection of spirochetes of the genus Borrelia. Symptoms of the disease include erythema migrans and flu-like symptoms.
Central nervous system diseases, also known as central nervous system disorders, are a group of neurological disorders that affect the structure or function of the brain or spinal cord, which collectively form the central nervous system (CNS).
The Central Nervous System controls most of the functions of the body and mind. It comprises the brain, spinal cord and the nerve fibers that branch off to all parts of the body. The Central Nervous System viral diseases are caused by viruses that attack the CNS. Existing and emerging viral CNS infections are major sources of human morbidity and mortality. Virus infections usually begin in the peripheral tissues, and can invade the mammalian system by spreading into the peripheral nervous system and more rarely the CNS. CNS is protected by effective immune responses and multi-layer barriers, but some viruses enter with high-efficiency through the bloodstream and some by directly infecting the nerves that innervate the tissues. Most viruses that enter can be opportunistic and accidental pathogens, but some like herpes viruses and rabies virus have evolved in time to enter the nervous system efficiently, by exploiting the neuronal cell biology. While acute viral diseases come on quickly, chronic viral conditions have long incubation periods inside the body. Their symptoms develop slowly and follow a progressive, fatal course.
Neurovirology is an interdisciplinary field which represents a melding of clinical neuroscience, virology, immunology, and molecular biology. The main focus of the field is to study viruses capable of infecting the nervous system. In addition to this, the field studies the use of viruses to trace neuroanatomical pathways, for gene therapy, and to eliminate detrimental populations of neural cells.
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