West Nile fever is caused by West Nile Virus, which was first recognized in the 1930s in Africa and first seen in humans in the United States in 1999. Most human infection is asymptomatic when symptoms are present, headache and fever are commonly seen and in severe case, it may progress to meningitis.
It is a vector-borne disease, transmitted by Culex mosquitoes; their biting habit is from evening to morning.
Incubation Period: 5 to 15 days
There is no specific diagnostic test.
Diagnosis of the West Nile Virus infection can be done by physical examination
Laboratory tests: Antibody test against West Nile Virus –
- IgG antibody sero-conversion (or significant increase in antibody titters) in two serial specimen collected at a one week interval by enzyme-linked immunosorbent assay (ELISA);
- IgM antibody capture enzyme-linked immunosorbent assay (ELISA);
- neutralisation assays;
- viral detection by reverse transcription polymerase chain reaction (RT-PCR) assay, and
- Virus isolation by cell culture.
Plaque-Reduction Neutralization Tests (PRNTs) can confirm acute infection but laboratories are not doing it widely
A diagnostic lumbar puncture may give signs of meningitis like elevated WBCs in CSF and antibodies of West Nile Virus (WNV specific IgM antibodies).
The EEG and MRI brain may give details about brain inflammation.
There is no specific treatment or prevention against West Nile fever. Standard precaution against mosquitoes should be taken
Health education regarding prevention of transmission and mosquito control is an important intervention
Full sleeve shirt and full leg covering pants
Use of mosquito repellents
Preventing Infection among health workers
Reducing the risk of transmission through blood transfusion, organ transplant and through vertical transmission in the area of outbreak.
Birds are believed to be natural reservoir of this virus and mosquitoes become infected when feeding on birds and can transmit the virus to animals and humans. There is no human-to-human transmission of the virus and no evidence of transfer from infected birds to humans, but it may be transmitted by infected blood transfusion. However, as a precaution, it is better to teach people in affected areas to wear gloves if handling a dead bird.
Patients are treated with fluid replacement, airway management, pain medication and standard nursing care when meningitis symptoms are present.
Interferon Therapy: Some research shows that interferon therapy is effective to early recover when comparing with people who don’t receive the drug but more studies should be needed.
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