West nile virus history and symptoms: Difference between revisions

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{{West nile virus}}
{{West nile virus}}
{{CMG}}
{{CMG}}; {{AE}} {{Ammu}}; {{Rim}}


==Overview==
==Overview==
{{CMG}}
WNV infection is considered a clinical spectrum. Infection due to WNV may have any of 3 different clinical presentations: Asymptomatic (~70-80%), mild [[febrile]] syndrome termed West Nile fever (~20%), and neuroinvasive disease termed West Nile [[meningitis]] or [[encephalitis]] (<1%). Patients who are suspected to have WNV infection should specifically be inquired about recent mosquito bites.


West nile fever, caused by Flavivirus transmitted by mosquito can present as a completely asymptomatic infection to mild fever to severe encephalitis,meningitis coma and death.
==History==
 
Patients who are suspected to have West Nile virus infection should be inquired about recent mosquito bites. In addition, important clues in the history include the time of the year, geographical location, recent travel, and outdoor activities. Patients should also be asked about virus-associated symptoms and their progression.
==History and Symptoms==
West Nile Fever is caused by Flavivirus. Birds are the natural reservoir of the virus and the virus is most commonly is trasmitted by mosquitoes. It is transmitted by many types of mosquitoes especially Culex mosquitoes. They carry the highest amount of risk of transmission in early fall and so the rate of disease is highest in late August to early September. After that the rate decreases as the mosquitoes cannot tolerate the cold. <ref name="pmidPMH0004457">{{cite journal| author=Kantrowitz ER, Lipscomb WN| title=An essential residue at the active site of aspartate transcarbamylase. | journal=J Biol Chem | year= 1976 | volume= 251 | issue= 9 | pages= 2688-95 | pmid=PMH0004457 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=4457  }} </ref> It is also found in horses and vaccines are available for the disease in horses but not for human beings. The virus may also be transmitted through contact with other infected animals, their blood, or other tissues.A very small proportion of human infections have occurred through organ transplant, blood transfusions and breast milk. There is one reported case of transplacental (mother-to-child) WNV transmission. To date, no human-to-human transmission of WNV through casual contact has been documented, and no transmission of WNV to health care workers has been reported when standard infection control precautions have been put in place.
Transmission of WNV to laboratory workers has been reported. 80% of the people infected with West Nile Virus are not aware that they are infected as it can be asymptomatic. West Nile fever can present with a variety of manifestation according to the severity of the diseases. It has three different effects on humans.
 
1) The first is an [[asymptomatic]] infection
 
2) The second is a mild [[febrile]] syndrome termed West Nile Fever;<ref>Olejnik E. "Infectious adenitis transmitted by ''Culex molestus''." ''Bull. Res. Counc. Isr.'' 1952; 2:
210-211.</ref>
 
3) The third is a neuroinvasive disease termed West Nile [[meningitis]] or [[encephalitis]].<ref>Smithburn K C, Jacobs H R. "Neutralization-tests against neurotropic viruses with sera collected in central Africa." ''Journal of Immunology'' 1942; 44: 923.</ref> In infected individuals the ratio between the three states is roughly 110:30:1.<ref>Tsai T F, Popovici F, Cernescu C, Campbell G L, Nedelcu N I. "West Nile encephalitis epidemic in south eastern Romania." ''Lancet'' 1998; 352: 767-771</ref>


==Symptoms==
==Symptoms==
===Asymptomatic variant===
===Asymptomatic===
This is found in almost 80% of the people where the patients are asymptomatic and unaware that they have been infected.
An asymptomatic course of the disease is observed among approximately 80% of individuals infected with WNV.


===West nile fever===
===West Nile fever===
The second, febrile stage has an [[incubation period]] of 3-8 days. The common symptoms found during this period in various systems are
====Constitutional symptoms====
====Constitutional symptoms====
* [[Fever]]
* [[Fever]]
* [[Chills]]
* [[Chills]]
* [[Headache]]
* [[Ache|Body aches]]
* [[Body aches]]
* [[Fatigue]]
* [[Fatigue]]
* [[Back pain]]
* [[Arthralgia]]
* [[Diaphoresis]]
* [[Diaphoresis]]
* Drowsiness
* [[Drowsiness]]
* Eye pain
* [[Anorexia]]
*[[ Insomnia]]


====Skin====
====HEENT symptoms====
* Skin [[rash]] on the trunk of the body
* [[Headache]]
* Swelling of lymph nodes
* [[Ocular pain]]
* [[Hearing impairment]]
* [[Cough]]


====GIT====
====Gastrointestinal symptoms====
* [[Nausea]]
* [[Nausea]]
* [[Vomiting]]
* [[Vomiting]]
* [[Loss of apetite]]
* [[Diarrhea]]
* [[Diarrhea]]


All symptoms are resolved within 7-10 days, although fatigue can last for some weeks and lymphadenopathy can take up to two months to resolve.
====Genitourinary symptoms====
* [[Bladder urgency]]
* [[Urinary incontinence]]
 
====Cutaneous manifestations====
* Macular or papular skin [[rash]] on the trunk
* [[Lymphadenopathy]]
 
===Neuroinvasive disease===
Neuroinvasive disease is the most severe form of WNV infection. Patients can present with fever associated with a wide range of neurological manifestations, such as flaccid paralysis, symptoms of meningitis or encephelatitis, or a combination of these conditions.


===Severe form with neurovascular disease===
====Constitutional symptoms====
The third effect is the most dangerous one with severe life threatening symptoms. It is called West Nile encephalitis or West Nile meningitis, depending on what part of the body is affected.  It is estimated that approximately 1 in 150 persons infected with the West Nile virus will develop a more severe form of disease. Serious illness can occur in people of any age, however people over the age of 50 and some immunocompromised persons (for example, transplant patients) are at the highest risk for getting severely ill when infected with WNV. The incubation period is usually 3 to 14 days.
The major symptoms are
====General====
* High [[fever]]
* High [[fever]]
* [[Pain]]
* [[Diffuse body aches]]
 
====Neurological====


It is the most severe form of the disease. They can present with a variety of manifestation in conjunction with fever like meningitis, flaccid paralysis, encephalitis or a combination of these .
====Neurological symptoms====
The most common neurological symptoms with their corresponding frequencies are tabulated below.
Shown below is a table of the most common neurological symptoms of neuroinvasive WNV disease with their corresponding frequencies.<ref name="Neurologic Complications of West Nile Virus">{{Cite web  | last =  | first =  | title = Neurologic Complications of West Nile Virus |  url = http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/neurology/neurologic-complications-west-nile-virus/ }}</ref>
{|style=" border: 0px; font-size: 90%; margin: 3px;"
{|style=" border: 0px; font-size: 90%; margin: 3px;"
! style="padding: 0 5px; width: 150px; background: #4479BA; font-weight: bold;"| {{fontcolor|#FFFFFF|Symptom}}
! style="padding: 0 5px; width: 150px; background: #4479BA; font-weight: bold;"| {{fontcolor|#FFFFFF|Symptom}}
! style="padding: 0 5px; width: 50px; background: #4479BA; font-weight: bold;" | {{fontcolor|#FFFFFF|Percentage}}
! style="padding: 0 5px; width: 50px; background: #4479BA; font-weight: bold;" | {{fontcolor|#FFFFFF|Percentage}}
|-
|-
| style="padding: 0 5px; background: #DCDCDC;" | [[Facial Palsy]]
| style="padding: 0 5px; background: #DCDCDC;" | [[Facial palsy]]
| style="padding: 0 5px; background: #F5F5F5;" | 13%
| style="padding: 0 5px; background: #F5F5F5;" | 13%
|-
|-
| style="padding: 0 5px; background: #DCDCDC;" | [[ Dhyphagia]]
| style="padding: 0 5px; background: #DCDCDC;" | [[ Dysphagia]]
| style="padding: 0 5px; background: #F5F5F5;" | 33%
| style="padding: 0 5px; background: #F5F5F5;" | 33%
|-
|-
Line 89: Line 83:
| style="padding: 0 5px; background: #F5F5F5;" | 31%
| style="padding: 0 5px; background: #F5F5F5;" | 31%
|}
|}
* Deep tendon reflexes are hyperactive at first, later diminished. There are also [[extrapyramidal disorder]]s. Recovery is marked by a long convalescence with fatigue. More recent outbreaks have resulted in a deeper study of the disease and other, rarer, outcomes have been identified.The spinal cord may be infected, marked by [[anterior myelitis]] with or without encephalitis.<ref>Sejvar J J, Haddad M B, Tierney B C, Campbell G L, Marfin A A, VanGerpen J A, Fleischauer A, Leis A A, Stokic D S, Petersen L R. "Neurologic manifestations and outcome of West Nile virus infection." ''JAMA'' 2003; 290: 511-515.</ref> WNV-associated [[Guillain-Barré syndrome]] has been identified<ref>Ahmed S, Libman R, Wesson K, Ahmed F, Einberg K. "Guillain-Barre syndrome: an unusual presentation of West Nile virus infection." ''Neurology'' 2000; 55: 144-146.</ref>
====West nile meningitis====
The main signs and symptoms  are back pain, myalgia, rash , photophobia. Usually it is aseptic meningitis and resolves without major complications.
====West nile meningoencephalitis====
It is the most common form of severe disease presenting as behavioual changes like confusion, irritability, disorientation along with focal signs like tremor, ataxia , bulbar dysfunction, or focal weakness.
====Acute flaccid paralysis====
It usually occurs in the subclinical phase presenting as lower limb weakness  with flaccid tone, areflexia or hyporeflexia.


====Multiorgan abnormality====
=====West Nile meningitis=====
* [[Headache]]
* [[Photophobia]]
* [[Neck stiffness]]
* [[Tremor]]
* [[Seizure]]
* [[Paralysis]]
* [[Rash]]


* [[Chorioretinitis]] (which has 100% specificity for identifying WNV infection in patients with possible WNV encephalitis)<ref>Abroug F, Ouanes-Besbes L, Letaief M, Ben Romdhane F, Khairallah M, Triki H, Bouzouiaia N. "A cluster study of predictors of severe West Nile virus infection." ''Mayo Clinic Proceedings'' 2006; 81: 12-16.</ref>
=====West Nile meningoencephalitis=====
* [[Confusion]]
* [[Irritability]]
* [[Disorientation]]
* [[Tremor]]
* [[Ataxia]]
* [[Bulbar dysfunction]]
* Focal weakness
* [[Sensory loss]]
* [[Memory loss]]
* [[Diplopia]]
* [[Cranial nerve palsy]]
 
=====Acute flaccid paralysis=====
* Lower limb weakness
 
====Multiorgan involvement====
* [[Chorioretinitis]]: Very specific for identifying WNV virus infection among patients with high pre-test probability<ref>Abroug F, Ouanes-Besbes L, Letaief M, Ben Romdhane F, Khairallah M, Triki H, Bouzouiaia N. "A cluster study of predictors of severe West Nile virus infection." ''Mayo Clinic Proceedings'' 2006; 81: 12-16.</ref>
* [[Hepatitis]]
* [[Hepatitis]]
* [[Myocarditis]]
* [[Myocarditis]]
* [[Nephritis]]
* [[Nephritis]]
* [[Pancreatitis]]
* [[Pancreatitis]]
* [[Splenomegaly]].<ref>Perelman A, Stern J. "Acute pancreatitis in West Nile Fever." ''American Journal of Tropical Medicine and Hygiene'' 1974; 23: 1150-1152.</ref><ref>Omalu B I, Shakir A A, Wang G, Lipkin W I, Wiley C A. "Fatal fulminant pan-meningo-polioencephalitis due to West Nile virus." ''Brain Pathology'' 2003; 13: 465-472</ref><ref>Mathiot C C, Georges A J, Deubel V. "Comparative analysis of West Nile virus strains isolated from human and animal hosts using monoclonal antibodies and cDNA restriction digest profiles." ''Res Virol'' 1990; 141: 533-543.</ref>
* [[Splenomegaly]]<ref>Perelman A, Stern J. "Acute pancreatitis in West Nile Fever." ''American Journal of Tropical Medicine and Hygiene'' 1974; 23: 1150-1152.</ref><ref>Omalu B I, Shakir A A, Wang G, Lipkin W I, Wiley C A. "Fatal fulminant pan-meningo-polioencephalitis due to West Nile virus." ''Brain Pathology'' 2003; 13: 465-472</ref><ref>Mathiot C C, Georges A J, Deubel V. "Comparative analysis of West Nile virus strains isolated from human and animal hosts using monoclonal antibodies and cDNA restriction digest profiles." ''Res Virol'' 1990; 141: 533-543.</ref>


==References==
==References==
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[[Category:Disease]]
[[Category:Disease]]
[[Category:Infectious disease]]
 
[[Category:Neurology]]
[[Category:Neurology]]

Latest revision as of 19:11, 18 September 2017

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ammu Susheela, M.D. [2]; Rim Halaby, M.D. [3]

Overview

WNV infection is considered a clinical spectrum. Infection due to WNV may have any of 3 different clinical presentations: Asymptomatic (~70-80%), mild febrile syndrome termed West Nile fever (~20%), and neuroinvasive disease termed West Nile meningitis or encephalitis (<1%). Patients who are suspected to have WNV infection should specifically be inquired about recent mosquito bites.

History

Patients who are suspected to have West Nile virus infection should be inquired about recent mosquito bites. In addition, important clues in the history include the time of the year, geographical location, recent travel, and outdoor activities. Patients should also be asked about virus-associated symptoms and their progression.

Symptoms

Asymptomatic

An asymptomatic course of the disease is observed among approximately 80% of individuals infected with WNV.

West Nile fever

Constitutional symptoms

HEENT symptoms

Gastrointestinal symptoms

Genitourinary symptoms

Cutaneous manifestations

Neuroinvasive disease

Neuroinvasive disease is the most severe form of WNV infection. Patients can present with fever associated with a wide range of neurological manifestations, such as flaccid paralysis, symptoms of meningitis or encephelatitis, or a combination of these conditions.

Constitutional symptoms

Neurological symptoms

Shown below is a table of the most common neurological symptoms of neuroinvasive WNV disease with their corresponding frequencies.[1]

Symptom Percentage
Facial palsy 13%
Dysphagia 33%
Dysarthria 33%
Diplopia 33%
Tremor 22%
Parkinsonism 16%
Ataxia 31%
Motor seizures 5%
Myoclonus 31%
West Nile meningitis
West Nile meningoencephalitis
Acute flaccid paralysis
  • Lower limb weakness

Multiorgan involvement

References

  1. ↑ "Neurologic Complications of West Nile Virus".
  2. ↑ Abroug F, Ouanes-Besbes L, Letaief M, Ben Romdhane F, Khairallah M, Triki H, Bouzouiaia N. "A cluster study of predictors of severe West Nile virus infection." Mayo Clinic Proceedings 2006; 81: 12-16.
  3. ↑ Perelman A, Stern J. "Acute pancreatitis in West Nile Fever." American Journal of Tropical Medicine and Hygiene 1974; 23: 1150-1152.
  4. ↑ Omalu B I, Shakir A A, Wang G, Lipkin W I, Wiley C A. "Fatal fulminant pan-meningo-polioencephalitis due to West Nile virus." Brain Pathology 2003; 13: 465-472
  5. ↑ Mathiot C C, Georges A J, Deubel V. "Comparative analysis of West Nile virus strains isolated from human and animal hosts using monoclonal antibodies and cDNA restriction digest profiles." Res Virol 1990; 141: 533-543.


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