Neurotropic virus

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A neurotropic virus is a virus that is capable of infecting nerve tissue. [1]

Contents

Terminology

A neurotropic virus is said to be neuroinvasive if it is capable of accessing or entering the nervous system and neurovirulent if it is capable of causing disease within the nervous system. Both terms are often applied to central nervous system infections, although some neurotropic viruses are highly neuroinvasive for the peripheral nervous system (e.g. herpes simplex virus). Important neuroinvasive viruses include poliovirus, which is highly neurovirulent but weakly neuroinvasive, and rabies virus, which is highly neurovirulent but requires tissue trauma (often resulting from an animal bite) to become neuroinvasive. Using these definitions, herpes simplex virus is highly neuroinvasive for the peripheral nervous system and rarely neuroinvasive for the central nervous system, but in the latter case may cause herpesviral encephalitis and is therefore considered highly neurovirulent. Many arthropod-borne neurotropic viruses, like West Nile virus, spread to the brain primarily via the blood system by crossing the blood–brain barrier in what is called hematogenous dissemination.[ citation needed ]

Examples

Neurotropic viruses that cause infection include Japanese Encephalitis, Venezuelan Equine Encephalitis, and California encephalitis viruses; polio, coxsackie, echo, mumps, measles, influenza and rabies, as well as diseases caused by members of the family Herpesviridae such as herpes simplex, varicella-zoster, Epstein–Barr, cytomegalovirus and HHV-6 viruses. [2] All seven of the known human coronaviruses are neurotropic, the common cold viruses mainly in vulnerable populations while the more virulent SARS-CoV-1, MERS, and SARS-CoV-2 frequently attack the nervous systems (primarily in animal models). [3]

Those causing latent infection include herpes simplex and varicella-zoster viruses. Those causing slow virus infection include measles virus, rubella and JC viruses, and retroviruses such as human T-lymphotropic virus 1 and HIV.[ citation needed ]

Research use

Neurotropic viruses are increasingly being exploited as research tools, and for their potential use in treatment. In particular, they are being used to improve the understanding of the nervous systems circuits. [4] [5]

Other neurotropic infections

Several diseases, including transmissible spongiform encephalopathy, kuru, and Creutzfeldt–Jakob disease resemble a slow neurotropic virus infection—but are, in fact, caused by the infectious proteins known as prions. [2]

See also

Related Research Articles

<span class="mw-page-title-main">Encephalitis</span> Inflammation of the brain

Encephalitis is inflammation of the brain. The severity can be variable with symptoms including reduction or alteration in consciousness, headache, fever, confusion, a stiff neck, and vomiting. Complications may include seizures, hallucinations, trouble speaking, memory problems, and problems with hearing.

<span class="mw-page-title-main">Viral meningitis</span> Medical condition

Viral meningitis, also known as aseptic meningitis, is a type of meningitis due to a viral infection. It results in inflammation of the meninges. Symptoms commonly include headache, fever, sensitivity to light and neck stiffness.

<span class="mw-page-title-main">Varicella zoster virus</span> Herpes virus that causes chickenpox and shingles

Varicella zoster virus (VZV), also known as human herpesvirus 3 or Human alphaherpesvirus 3 (taxonomically), is one of nine known herpes viruses that can infect humans. It causes chickenpox (varicella) commonly affecting children and young adults, and shingles in adults but rarely in children. VZV infections are species-specific to humans. The virus can survive in external environments for a few hours.

<span class="mw-page-title-main">Shingles</span> Viral disease caused by the varicella zoster virus

Shingles, also known as herpes zoster, is a viral disease characterized by a painful skin rash with blisters in a localized area. Typically the rash occurs in a single, wide mark either on the left or right side of the body or face. Two to four days before the rash occurs there may be tingling or local pain in the area. Other common symptoms are fever, headache, and tiredness. The rash usually heals within two to four weeks; however, some people develop ongoing nerve pain which can last for months or years, a condition called postherpetic neuralgia (PHN). In those with poor immune function the rash may occur widely. If the rash involves the eye, vision loss may occur.

<span class="mw-page-title-main">Aseptic meningitis</span> Medical condition

Aseptic meningitis is the inflammation of the meninges, a membrane covering the brain and spinal cord, in patients whose cerebral spinal fluid test result is negative with routine bacterial cultures. Aseptic meningitis is caused by viruses, mycobacteria, spirochetes, fungi, medications, and cancer malignancies. The testing for both meningitis and aseptic meningitis is mostly the same. A cerebrospinal fluid sample is taken by lumbar puncture and is tested for leukocyte levels to determine if there is an infection and goes on to further testing to see what the actual cause is. The symptoms are the same for both meningitis and aseptic meningitis but the severity of the symptoms and the treatment can depend on the certain cause.

Viral pneumonia is a pneumonia caused by a virus. Pneumonia is an infection that causes inflammation in one or both of the lungs. The pulmonary alveoli fill with fluid or pus making it difficult to breathe. Pneumonia can be caused by bacteria, viruses, fungi or parasites. Viruses are the most common cause of pneumonia in children, while in adults bacteria are a more common cause.

<span class="mw-page-title-main">Neuritis</span> Inflammation of a nerve or generally any part of the nervous system

Neuritis is inflammation of a nerve or the general inflammation of the peripheral nervous system. Inflammation, and frequently concomitant demyelination, cause impaired transmission of neural signals and leads to aberrant nerve function. Neuritis is often conflated with neuropathy, a broad term describing any disease process which affects the peripheral nervous system. However, neuropathies may be due to either inflammatory or non-inflammatory causes, and the term encompasses any form of damage, degeneration, or dysfunction, while neuritis refers specifically to the inflammatory process.

<span class="mw-page-title-main">Viral encephalitis</span> Medical condition

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.

<span class="mw-page-title-main">Herpetic gingivostomatitis</span> Medical condition

Gingivostomatitis is a combination of gingivitis and stomatitis, or an inflammation of the oral mucosa and gingiva. Herpetic gingivostomatitis is often the initial presentation during the first ("primary") herpes simplex infection. It is of greater severity than herpes labialis which is often the subsequent presentations. Primary herpetic gingivostomatitis is the most common viral infection of the mouth.

<span class="mw-page-title-main">Meningoencephalitis</span> Medical condition

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 tissue.

<span class="mw-page-title-main">Mollaret's meningitis</span> Medical condition

Mollaret's meningitis is a recurrent or chronic inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. Since Mollaret's meningitis is a recurrent, benign (non-cancerous), aseptic meningitis, it is also referred to as benign recurrent lymphocytic meningitis. It was named for Pierre Mollaret, the French neurologist who first described it in 1944.

The central nervous system (CNS) 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 CNS viral diseases are caused by viruses that attack the CNS. Existing and emerging viral CNS infections are major sources of human morbidity and mortality.

<span class="mw-page-title-main">Chickenpox</span> Human viral disease

Chickenpox, or chicken pox, also known as varicella, is a highly contagious, vaccine-preventable disease caused by the initial infection with varicella zoster virus (VZV), a member of the herpesvirus family. The disease results in a characteristic skin rash that forms small, itchy blisters, which eventually scab over. It usually starts on the chest, back, and face. It then spreads to the rest of the body. The rash and other symptoms, such as fever, tiredness, and headaches, usually last five to seven days. Complications may occasionally include pneumonia, inflammation of the brain, and bacterial skin infections. The disease is usually more severe in adults than in children.

<span class="mw-page-title-main">Herpes</span> Viral disease caused by herpes simplex viruses

Herpes simplex, often known simply as herpes, is a viral infection caused by the herpes simplex virus. Herpes infections are categorized by the area of the body that is infected. The two major types of herpes are oral herpes and genital herpes, though other forms also exist.

<span class="mw-page-title-main">Herpes simplex encephalitis</span> Encephalitis associated with herpes simplex virus

Herpes simplex encephalitis (HSE), or simply herpes encephalitis, is encephalitis due to herpes simplex virus. It is estimated to affect at least 1 in 500,000 individuals per year, and some studies suggest an incidence rate of 5.9 cases per 100,000 live births.

<span class="mw-page-title-main">Cold sore</span> Herpes simplex virus infection of the lip

A cold sore is a type of herpes infection caused by the herpes simplex virus that affects primarily the lip. Symptoms typically include a burning pain followed by small blisters or sores. The first attack may also be accompanied by fever, sore throat, and enlarged lymph nodes. The rash usually heals within ten days, but the virus remains dormant in the trigeminal ganglion. The virus may periodically reactivate to create another outbreak of sores in the mouth or lip.

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.

In the United States, the National Notifiable Disease Surveillance System (NNDSS) is responsible for sharing information regarding notifiable diseases. As of 2020, the following are the notifiable diseases in the US as mandated by the Centers for Disease Control and Prevention:

References

  1. "neurotropic - WordReference.com Dictionary of English". www.wordreference.com.
  2. 1 2 Hotta H (April 1997). "神経親和性ウイルス" [Neurotropic viruses--classification, structure and characteristics]. Nihon Rinsho (in Japanese). 55 (4): 777–82. PMID   9103870. S2CID   11123404.
  3. Morgello, Susan (31 July 2020). "Coronaviruses and the central nervous system". Journal of Neurovirology. 26 (4): 459–473. doi:10.1007/s13365-020-00868-7. PMC   7393812 . PMID   32737861.
  4. Advances in Virus Research. Academic Press. October 17, 2000. ISBN   9780080524535 via Google Books.
  5. Kennedy, P. G. E. (1 August 2003). "Neurovirological methods and their applications". Journal of Neurology, Neurosurgery & Psychiatry. 74 (8): 1016–1022. doi:10.1136/jnnp.74.8.1016. PMC   1738595 . PMID   12876227.