Skip to main content
Advertisement
  • Neurology.org
  • Journals
    • Neurology
    • Clinical Practice
    • Genetics
    • Neuroimmunology & Neuroinflammation
    • Education
  • Online Sections
    • Neurology Video Journal Club
    • Inclusion, Diversity, Equity, Anti-racism, & Social Justice (IDEAS)
    • Innovations in Care Delivery
    • Practice Buzz
    • Practice Current
    • Residents & Fellows
    • Without Borders
  • Collections
    • COVID-19
    • Disputes & Debates
    • Health Disparities
    • Infographics
    • Null Hypothesis
    • Patient Pages
    • Topics A-Z
    • Translations
  • Podcast
  • CME
  • About
    • About the Journals
    • Contact Us
    • Editorial Board
  • Authors
    • Submit a Manuscript
    • Author Center

Advanced Search

Main menu

  • Neurology.org
  • Journals
    • Neurology
    • Clinical Practice
    • Genetics
    • Neuroimmunology & Neuroinflammation
    • Education
  • Online Sections
    • Neurology Video Journal Club
    • Inclusion, Diversity, Equity, Anti-racism, & Social Justice (IDEAS)
    • Innovations in Care Delivery
    • Practice Buzz
    • Practice Current
    • Residents & Fellows
    • Without Borders
  • Collections
    • COVID-19
    • Disputes & Debates
    • Health Disparities
    • Infographics
    • Null Hypothesis
    • Patient Pages
    • Topics A-Z
    • Translations
  • Podcast
  • CME
  • About
    • About the Journals
    • Contact Us
    • Editorial Board
  • Authors
    • Submit a Manuscript
    • Author Center
  • Home
  • Latest Articles
  • Current Issue
  • Past Issues
  • Residents & Fellows

User menu

  • Subscribe
  • My Alerts
  • Log in

Search

  • Advanced search
Neurology
Home
The most widely read and highly cited peer-reviewed neurology journal
  • Subscribe
  • My Alerts
  • Log in
Site Logo
  • Home
  • Latest Articles
  • Current Issue
  • Past Issues
  • Residents & Fellows

Share

January 27, 2015; 84 (4) Global Perspectives

Arbovirus infections of the nervous system: Current trends and future threats

Mohammad Wasay, Ismail A. Khatri, Foad Abd-Allah
First published January 26, 2015, DOI: https://doi.org/10.1212/WNL.0000000000001177
Mohammad Wasay
From the Division of Neurology (M.W.), Department of Medicine, The Aga Khan University, Karachi, Pakistan; the Division of Neurology (I.A.K.), Department of Medicine, King Abdulaziz Medical City, National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia; and the Department of Neurology (F.A.-A.), Cairo University, Cairo, Egypt.
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Ismail A. Khatri
From the Division of Neurology (M.W.), Department of Medicine, The Aga Khan University, Karachi, Pakistan; the Division of Neurology (I.A.K.), Department of Medicine, King Abdulaziz Medical City, National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia; and the Department of Neurology (F.A.-A.), Cairo University, Cairo, Egypt.
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Foad Abd-Allah
From the Division of Neurology (M.W.), Department of Medicine, The Aga Khan University, Karachi, Pakistan; the Division of Neurology (I.A.K.), Department of Medicine, King Abdulaziz Medical City, National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia; and the Department of Neurology (F.A.-A.), Cairo University, Cairo, Egypt.
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Full PDF
Citation
Arbovirus infections of the nervous system: Current trends and future threats
Mohammad Wasay, Ismail A. Khatri, Foad Abd-Allah
Neurology Jan 2015, 84 (4) 421-423; DOI: 10.1212/WNL.0000000000001177

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
Permissions

Make Comment

See Comments

Downloads
1526

Share

  • Article
  • Figures & Data
  • Info & Disclosures
Loading

Systemic viral infections are common. Symptomatic involvement of the nervous system in viral infections is uncommon.1 Encephalitis is the most worrying manifestation of nervous system involvement by viruses. Arthropod-borne viruses (arboviruses) are among the most serious international infectious threats to the human nervous system.2 The neurologic diseases that may be transmitted by arthropods to humans include meningitis, encephalitis, myelitis, encephalomyelitis, neuritis (including anterior horn cells and dorsal root ganglia), and myositis.2

Arboviruses are distributed worldwide. Different species, however, have a predilection for different geographical areas. Arboviruses are transmitted to vertebral hosts by blood-feeding arthropod vectors including mosquitoes, biting flies, mites, nits, and ticks.2,3 The table reviews some of the common arboviruses, their vectors, and their geographical distribution. Transmission pattern of arboviruses is climate-dependent and is broadly divided into 2 groups. In tropical areas, viruses circulate throughout the year, often with a broad seasonal peak. Pattern is different in temperate climates, where virus is transmitted between the vector and vertebrate host species only during the warmer months with no arboviral disease in colder months.4

View this table:
  • View inline
  • View popup
  • Download powerpoint
Table

Common arboviruses with their geographical distribution and vectors

Arboviruses that affect the nervous system are RNA viruses of several genera of the Togaviridae, Flaviviridae, Bunyaviridae, Reoviridae, and Orthomyxoviridae families.2,3,5 These arboviruses replicate in peripheral tissues, produce viremia, enter the CNS, replicate in neurons, and spread outward to other neuron populations, a process that may lead to encephalitis.6 Some of the well-known encephalitides include West Nile encephalitis (WNE), Dengue fever encephalitis (DFE), St. Louis encephalitis, Japanese encephalitis (JE), Toscana encephalitis, Crimean-Congo hemorrhagic fever, Chikungunya virus encephalitis (CHIKV), Eastern equine encephalitis (EEE), and Western equine encephalitis (WEE).

The clinical features of most encephalitogenic arboviruses include varying degrees of meningoencephalomyelitis. Fever, headache, malaise, body aches, vomiting, and nausea usually precede the neurologic manifestation and occur within days after arthropod bite.2 Disease severity varies among individuals. A virus causing severe neurologic abnormalities or death in one individual may cause little or no disease in another.

A variety of neurologic symptoms and signs can occur due to arbovirus infection. Whereas seizures are common to almost all arbovirus encephalitides, JE, La Cross virus encephalitis (LCE), and tick-borne encephalitis (TBE) may result in chronic epilepsy.2 Stroke can occur in JE and EEE.2 Parkinsonism is common in DFE, JE, WNE, EEE, and WEE.7 The cerebellum and brainstem can be affected by a number of arboviruses.2 Peripheral neuropathy is more common with DFE, JE, WNE, and TBE.2

A high index of clinical suspicion remains important for the diagnosis of an arbovirus infection as laboratory and imaging findings can be nonspecific or normal, particularly in the early stages of disease. Characteristic arboviral CSF findings include lymphocytic pleocytosis with mild protein elevation. CSF glucose is usually normal, but low or high glucose levels can be seen with certain infections. Rapid serum or CSF antibody assays are available for most of the arboviruses.

Imaging findings may be nonspecific or normal in early or mild cases. Certain viruses have a predilection for certain areas of the brain. JE virus (JEV) can affect basal ganglia, brainstem, or spinal cord. The basal ganglia may also be involved in St. Louis encephalitis, LCE, and Murray Valley encephalitis. Edema of the substantia nigra has been reported in patients with St. Louis encephalitis.8 Temporal lobe and other focal cortical involvement can be seen with JE, LCE, and EEE.2 Spinal cord involvement (myelitis) may be present in DFE.9

A variety of EEG abnormalities can be seen in arbovirus encephalitides, including periodic lateralized epileptiform discharges, status epilepticus, epilepsia partialis continua, and burst suppression. Nerve conduction and EMG abnormalities may be seen in DFE, WNE, JE, and TBE. Clinical, laboratory, radiologic, and neurophysiologic findings seen in arbovirus encephalitides are summarized in a recent review by Rust.2

There is no specific treatment of arbovirus infections. Neither steroids nor antivirals have been proven effective.2 Supportive treatment remains the mainstay.2 Treatment of seizures and raised intracranial pressure, along with maintenance of ventilatory and cardiac status, is important. Effective vaccines for prevention of viral encephalitides are available for only a few viral pathogens, including JEV. Vector control and avoiding bites remain the best available strategy for prevention.1

The keys to prevention of arboviral encephalitis include reducing prevalence of vectors, reducing host susceptibility, avoidance of the vector, and reduction of human susceptibility through the use of insect repellants or immunization.2 Effective human vaccines are available for prophylaxis of yellow fever, JE, and tick-borne encephalitis.10 Some of the widespread and dangerous encephalitides like Dengue and West Nile still lack a vaccine, although vaccines are in the development stage for Dengue virus, West Nile virus (WNV), and CHIKV.10,11 With the general resistance to chemical control of vectors, novel methods like genetic modification of vector populations are becoming increasingly important for research and development.12

Morbidity and mortality from nervous system infections due to arboviruses are substantial.13 Fatality rate ranges from <1% for LCE to as high as 70% in EEE.4 Permanent neurologic disability may result in as many as 90% of affected individuals depending on the virulence and type of the virus.1,2,4 These disabilities are myriad and include epilepsy, cognitive deficits, flaccid paralysis of limbs, focal neurologic deficits, blindness, and permanent vegetative state.1,2,4

Emergence and re-emergence of arboviral diseases are largely attributed to human behavior.4 Antropogenic changes, especially involving viral genetics, composition and dynamics of host and vector population, and envoirnmental factors, may substantially affect natural systems, leading to amplification of these arboviruses to epidemic levels.3 Modern travel and trade has facilitated the spread of arboviruses and highly efficient, anthropophilic mosquitoes throughout the globe.4

Poor living and sanitary conditions (highly prevalent in the developing world) may provide an ideal breeding ground for mosquitoes and environmental factors such as urbanization and crowded living conditions lead to increased human contact with arboviruses and their vectors.4

The geographical habitat of arboviruses has expanded in recent decades.14 WNV underwent a dramatic geographic expansion into the Americas beginning in 1999, whereas JEV from its origin in Indonesia and Malaysia has spread throughout most of Asia, as far south as Australia.3 With spread of JEV to most of the Indian subcontinent and the heavy commercial and passenger air travel from this region, Europe and Africa may be potential destinations for this life-threatening virus.3 Dengue, one of the most prevalent human arboviral pathogens with an estimated 50 to 100 million annual cases worldwide, has become one of the leading causes of hospitalization and death in children in Southeast Asia.15 Many regions in South Asia, including Pakistan, are now endemic for DFE.16 CHIKV, thought to have originated in Africa, has become endemic in many Southeast Asian countries as well as India.3,15 Toscana virus, first isolated from sand flies in the 1970s in Italy, has now become a significant pathogen, causing meningitis in the summer months in large parts of the Mediterranean region, including several European and North African countries.17

With the increasing threat from arboviruses, it is imperative that a multidisciplinary approach is used to prevent future catastrophes from these virulent pathogens. Disease surveillance is the cornerstone of response to emerging disease threats. Risk assessment and outbreak preparedness are imperative.15 Collaborative and integrated efforts are required to control vector populations through biological and nonbiological methods, avoid vector exposure, develop new vaccines, improve and implement mass vaccination programs, find effective therapies, increase surveillance, increase public awareness, and build capacity, particularly in endemic areas.14

AUTHOR CONTRIBUTIONS

Mohammad Wasay: study concept and design, manuscript writing, manuscript review. Ismail Khatri: study concept and design, manuscript writing. Foad Abd-Allah: manuscript writing, manuscript review.

STUDY FUNDING

No targeted funding reported.

DISCLOSURE

The authors report no disclosures relevant to the manuscript. Go to Neurology.org for full disclosures.

ACKNOWLEDGMENT

The authors thank Dr. Talha Vaqar and Musa Khan for help in obtaining cited articles.

Footnotes

  • Go to Neurology.org for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article.

  • © 2015 American Academy of Neurology

REFERENCES

  1. 1.↵
    1. Whitley RJ,
    2. Gnann JW
    . Viral encephalitis: familiar infections and emerging pathogens. Lancet 2002;359:507–513.
    OpenUrlCrossRefPubMed
  2. 2.↵
    1. Rust RS
    . Human arboviral encephalitis. Semin Pediatr Neurol 2012;19:130–151.
    OpenUrlPubMed
  3. 3.↵
    1. Weaver SC,
    2. Reisen WK
    . Present and future arboviral threats. Antivir Res 2010;85:328–345.
    OpenUrlCrossRefPubMed
  4. 4.↵
    1. Hollidge BS,
    2. González-Scarano F,
    3. Soldan SS
    . Arboviral encephalitides: transmission, emergence, and pathogenesis. J Neuroimmune Pharmacol 2010;5:428–442.
    OpenUrlCrossRefPubMed
  5. 5.↵
    1. Dobler G
    . Arboviruses causing neurological disorders in the central nervous system. Arch Virol Suppl 1996;11:33–40.
    OpenUrlPubMed
  6. 6.↵
    1. Griffin DE,
    2. Byrnes AP,
    3. Cook SH
    . Emergence and virulence of encephalitogenic arboviruses. Arch Virol Suppl 2004;21–33.
  7. 7.↵
    1. Channa R,
    2. Wasay M
    . CNS involvement in Dengue viral infection. Pakistan J Neurol Sci 2006;1:84–88.
    OpenUrl
  8. 8.↵
    1. Wasay M,
    2. Kojan S,
    3. Haq A,
    4. Van Ness P,
    5. Suss R,
    6. Diaz Arrastia R
    . Saint Louis encephalitis: a review of 11 cases in Dallas epidemic. Arch Neurol 2000;57:114–118.
    OpenUrlCrossRefPubMed
  9. 9.↵
    1. Wasay M,
    2. Channa R,
    3. Jumani M,
    4. Shabbir G,
    5. Azeemuddin M,
    6. Zafar A
    . Encephalitis and myelitis associated with Dengue infection. Clin Neurol Neurosurg 2008;110:635–640.
    OpenUrlCrossRefPubMed
  10. 10.↵
    1. Heinz FX,
    2. Stiasny K
    . Flaviviruses and flavivirus vaccines. Vaccine 2012;30:4301–4306.
    OpenUrlCrossRefPubMed
  11. 11.↵
    1. Brandler S,
    2. Tangy F
    . Vaccines in development against West Nile virus. Viruses 2013;5:2384–2409.
    OpenUrlPubMed
  12. 12.↵
    1. Niranjan Reddy B,
    2. Gupta B,
    3. Rao BP
    . Vector population manipulation for control of arboviruses: a novel prospect for India. Pest Manag Sci 2013;70:517–523.
    OpenUrlPubMed
  13. 13.↵
    1. Solomon T
    . Flavivirus encephalitis. N Engl J Med 2004;351:370–378.
    OpenUrlCrossRefPubMed
  14. 14.↵
    1. Ahmed J,
    2. Bouloy M,
    3. Ergonul O,
    4. et al
    . International network for capacity building for the control of emerging viral vector-borne zoonotic diseases: ARBO-ZOONET. Euro Surveill 2009;14.
  15. 15.↵
    1. Dash AP,
    2. Bhatia R,
    3. Sunyoto T,
    4. Mourya DT
    . Emerging and re-emerging arboviral diseases in Southeast Asia. J Vector Borne Dis 2013;50:77–84.
    OpenUrlPubMed
  16. 16.↵
    1. Wasay M,
    2. Channa R,
    3. Jumani M,
    4. Zafar A
    . Changing patterns and outcome of Dengue infection in Pakistan. JPMA 2008;58:488–489.
    OpenUrl
  17. 17.↵
    1. Charrel RN,
    2. Bichaud L,
    3. de Lamballerie X
    . Emergence of Toscana virus in the Mediterranean area. World J Virol 2012;1:135–141.
    OpenUrlPubMed
View Abstract

Disputes & Debates: Rapid online correspondence

No comments have been published for this article.
Comment

REQUIREMENTS

If you are uploading a letter concerning an article:
You must have updated your disclosures within six months: http://submit.neurology.org

Your co-authors must send a completed Publishing Agreement Form to Neurology Staff (not necessary for the lead/corresponding author as the form below will suffice) before you upload your comment.

If you are responding to a comment that was written about an article you originally authored:
You (and co-authors) do not need to fill out forms or check disclosures as author forms are still valid
and apply to letter.

Submission specifications:

  • Submissions must be < 200 words with < 5 references. Reference 1 must be the article on which you are commenting.
  • Submissions should not have more than 5 authors. (Exception: original author replies can include all original authors of the article)
  • Submit only on articles published within 6 months of issue date.
  • Do not be redundant. Read any comments already posted on the article prior to submission.
  • Submitted comments are subject to editing and editor review prior to posting.

More guidelines and information on Disputes & Debates

Compose Comment

More information about text formats

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
Author Information
NOTE: The first author must also be the corresponding author of the comment.
First or given name, e.g. 'Peter'.
Your last, or family, name, e.g. 'MacMoody'.
Your email address, e.g. higgs-boson@gmail.com
Your role and/or occupation, e.g. 'Orthopedic Surgeon'.
Your organization or institution (if applicable), e.g. 'Royal Free Hospital'.
Publishing Agreement
NOTE: All authors, besides the first/corresponding author, must complete a separate Publishing Agreement Form and provide via email to the editorial office before comments can be posted.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.

Vertical Tabs

You May Also be Interested in

Back to top
  • Article
    • AUTHOR CONTRIBUTIONS
    • STUDY FUNDING
    • DISCLOSURE
    • ACKNOWLEDGMENT
    • Footnotes
    • REFERENCES
  • Figures & Data
  • Info & Disclosures
Advertisement

Related Articles

  • No related articles found.

Topics Discussed

  • Bioterrorism
  • All epidemiology
  • MRI
  • Coma
  • Viral infections

Alert Me

  • Alert me when eletters are published
Neurology: 99 (1)

Articles

  • Ahead of Print
  • Current Issue
  • Past Issues
  • Popular Articles
  • Translations

About

  • About the Journals
  • Ethics Policies
  • Editors & Editorial Board
  • Contact Us
  • Advertise

Submit

  • Author Center
  • Submit a Manuscript
  • Information for Reviewers
  • AAN Guidelines
  • Permissions

Subscribers

  • Subscribe
  • Activate a Subscription
  • Sign up for eAlerts
  • RSS Feed
Site Logo
  • Visit neurology Template on Facebook
  • Follow neurology Template on Twitter
  • Visit Neurology on YouTube
  • Neurology
  • Neurology: Clinical Practice
  • Neurology: Genetics
  • Neurology: Neuroimmunology & Neuroinflammation
  • Neurology: Education
  • AAN.com
  • AANnews
  • Continuum
  • Brain & Life
  • Neurology Today

Wolters Kluwer Logo

Neurology | Print ISSN:0028-3878
Online ISSN:1526-632X

© 2022 American Academy of Neurology

  • Privacy Policy
  • Feedback
  • Advertise